Pulmonary AVM Embolization
Table of Contents
- Case Overview
- Statement of Consent
- Special Acknowledgements
Pulmonary arteriovenous malformations (PAVMs) are rare fistulous connections between pulmonary arteries and veins that, as in our case, are commonly associated with hereditary hemorrhagic telangiectasia (HHT). Embolotherapy, the mainstay of treatment for PAVMs, is a procedure in which the feeding arteries of a malformation are endovascularly occluded under fluoroscopic guidance. Effective and well-tolerated, embolotherapy has been shown to decrease right-to-left shunting following treatment and decrease risks of paradoxical embolization and lung hemorrhage and to improve pulmonary gas exchange and lung function. Patients are selected for treatment according to clinical suspicion for the presence of a PAVM and feeding artery diameter. The occlusion of PAVMs with arteries that exceed 2-3 mm in diameter is recommended.
Diagnostic contrast-enhanced pulmonary angiography is performed via injection of contrast through a percutaneous catheter to characterize and confirm PAVMs suitable for embolization. Lesions are then treated by catheter-directed placement of embolic material— vascular plugs in our case—into the feeding artery, terminating blood flow to the area of the lesion. Although multiple PAVMs may be embolized during a single session, in patients with HHT, who may present with large numbers of PAVMs, treatment is limited by maximum contrast dosage, and additional sessions may be performed if PAVMs remain perfused.
Pulmonary arteriovenous malformations (PAVMs) are rare fistulous connections between pulmonary arteries and veins that, as in our case, are commonly congenital and associated with hereditary hemorrhagic telangiectasia (HHT).1 Acquired PAVMs may occur secondary to liver disease or systemic disease, or following palliation of complex cyanotic congenital heart disease. Lesions may progress, with significant growth believed to occur during childhood and early adulthood as well as during pregnancy, leading to hemodynamic changes and intrapulmonary shunting.2 Clinically, this may manifest as hypoxemia, leading to cyanosis, clubbing, polycythemia, and impaired exercise tolerance. Pulmonary hemorrhage and paradoxical systemic embolization with stroke and cerebral abscesses may also occur with untreated lesions.3,4
The patient in this case was a 14-year-old female with occasional nosebleeds and past medical history of HHT (diagnosed clinically and confirmed with genetic testing). The patient also had family history pertinent for HHT in the patient’s biological mother. A screening chest CT found multiple PAVMs, 2 of which met the criteria for therapeutic embolization. A lesion with a 2.5 mm feeding artery was detected in the right upper lobe and the other PAVM with a 2 mm feeding artery was visualized in the left lower lobe.
Absence of symptoms does not preclude the diagnosis of PAVM, as case series have reported that 13-55% of adult and child patients with PAVMs are asymptomatic clinically. Dyspnea on exertion, attributable to hypoxemia from right-to-left shunting, is the most common presenting symptom.3 Epistaxis, headaches, hemoptysis, palpitations, chest pain, and cough are also frequently reported, and PAVMs should always be suspected in a patient with a history of stroke or brain abscess. Presentation of symptoms often correlates with saccular size. Lesions less than 2 cm in diameter on chest radiography are typically asymptomatic.3,5
Abnormal physical findings arising from vascular malformations are reported to be present in up to 75% of patients with PAVMs and most commonly include: cyanosis, clubbing, and pulmonary vascular murmurs or bruits over the area in which the PAVM is located. Intensity of the murmurs may be increased through inspiration and when the PAVM is in a dependent position, due to increased pulmonary blood flow. Expiration and the Valsalva maneuver decrease intensity of the murmur.5 Mucosal surfaces, trunk, and fingertips should be inspected for telangiectasias as roughly 66% of HHT patients with PAVMs will also present with mucocutaneous lesions.3,6 Pulse oximetry readings may show decreased oxygen saturation at room air post-exercise and at rest due to shunting.6 Blood gasses may also provide evidence of hypoxemia.
CT has a sensitivity of more than 95% when screening for PAVMs. Many patients present with abnormal findings on CT since contrast-enhanced pulmonary angiography is not routinely used for diagnostic evaluation of suspected lesions unless they are suitable for embolotherapy. Classic diagnostic CT findings include a round or oval nodule (<3 cm) or mass (>3 cm) of uniform density representing the sac, typically 0.5-5 cm in diameter and occasionally exceeding 10 cm in diameter, with visible feeding and draining vessels. Contrast-enhanced pulmonary arterial angiography is the gold standard for defining the anatomy of a previously identified PAVM for embolotherapy or definitive diagnosis. For sacs greater than 0.5 cm, findings typically include regions of contrast-enhancement with a feeding artery leading to abnormal arteriovenous communication and drainage subsequently by a pulmonary vein. Rendered three-dimensional images of complex malformations facilitate planning for transarterial embolizations and are especially helpful in lesions involving more than one feeding vessel.7,8
The natural history of PAVMs and true estimates of morbidity and mortality associated with untreated lesions are poorly understood, as the data consists primarily of retrospective case series. In the setting of HHT, morbidity and mortality are attributed to devastating neurological sequelae, stroke and brain abscess, from paradoxical emboli of thrombotic or septic origin. Hypoxemic respiratory failure and life-threatening hemoptysis and hemothorax may also occur.9-12
When left untreated, complication rates have been reported to reach 50% and exceed this value during pregnancy.13 Diffuse forms are associated with greater complications, with neurological morbidity reaching 70% in untreated lesions.14 Resultantly, current recommendations include screening at regular intervals in HHT families. This has given rise to questions regarding protocols as they pertain to children, as the need to minimize lifetime exposure to ionizing radiation must be balanced with the need to identify and mitigate risks associated with PAVM.15,16
To minimize the risk of neurologic and other complications from PAVM, embolotherapy is currently the preferred treatment in the majority of patients. Alternative therapies include surgical excision and lung transplantation. The possibility of excision exists for patients who have had repeated failed embolization attempts as well as patients with life-threatening acute hemorrhage in a facility without access to embolotherapy. Depending on the location and extent of PAVMs, surgical treatment of PAVMs includes vascular ligation, local excision, lobectomy, and pneumonectomy via either video-assisted thoracoscopic surgery or open thoracotomy, with morbidity and mortality for surgical intervention being comparable to other forms of thoracic surgeries. Lung transplantation is reserved for patients with refractory, often bilateral and diffuse disease, and those who are at increased risk of dying from complications.9,17
Although the optimal guidelines for screening and management of PAVMs in children and adolescents remain controversial, endovascular embolization is a feasible and safe method for treating pediatric PAVMs. The first large case series of pediatric patients undergoing embolization for PAVMs in 2004 by Faughnan et al. demonstrated that embolotherapy was safe in children and young adults and that complication rates were similar to those in adult patients.14 Reperfusion rates were noted to be 15% at 7 years.14 Although reperfusion rates remain relatively high in pediatric patients undergoing embolization therapy, in comparison to surgical intervention, the parenchyma-sparing benefit of embolization therapy as well as lower morbidity and shorter hospital stay make this the treatment of choice.2,14,18
Currently, embolization therapy is the preferred treatment of PAVMs and is performed in the absence of contraindications such as severe pulmonary hypertension, renal failure, and early pregnancy.19
In 1988, White et al. documented techniques and long-term outcomes of embolotherapy in patients with PAVMs, the majority of whom had underlying HHT, and emphasized the necessity for screening in these families due to the high risk of catastrophic neurological sequelae.20 Over the course of the following 3 decades, although developments in equipment and imaging have improved interventional outcomes and permitted the embolization of multiple and bilateral PAVMs during a single session, the guiding principles of treatment have largely remained constant.1,15 Occlusion of the feeding artery is designed to eliminate flow to the lesion, allowing for thrombosis and sac retraction.15
The first component of the procedure is diagnostic. Contrast-enhanced pulmonary angiography is used to confirm and characterize the presence of PAVMs, including lesions that were missed on previous CT imaging, that are suitable for embolization. Visualization of the lesions is achieved through insertion of a percutaneous catheter through the transfemoral or transjugular veins and injection of contrast into the right and left main pulmonary arteries.15
The second component of the procedure, limited by the maximum contrast dose per patient, is therapeutic embolization. Heparin is typically provided during the procedure to minimize the risk of thrombus formation on the catheter that could result in paradoxical emboli, estimated at less than 1%.15 To further reduce the risk of paradoxical emboli formation through entry of air into the circulation, it is recommended that air filters be applied to all IV lines and that wire and catheter exchanges be performed under saline immersion.21
The process of embolization begins with the localization of lesions within the lung parenchyma through selective contrast injections. Contrast is used to guide the placement of embolic material, most commonly non-ferrous coils or vascular plugs, into the feeding artery of the malformation until flow across the connection ceases. When using coils, the initial one should be 20-30% wider than the feeding artery.22 Vascular plugs, although more expensive and time-consuming, as they take longer to occlude flow, allow for precise deployment near the sac and have a lower risk of device migration.15 Furthermore, only 1 plug is generally needed compared with multiple coils, often offsetting their greater expense.
Postprocedure, patients are typically held for 2-3 hours in recovery and discharged the same day. The presence of additional PAVMs not treated in the first session may warrant additional intervention over the weeks or months following completion of the initial procedure.
The most common postprocedural complication, occurring in approximately 10% of patients, is self-limited pleuritic chest pain from thrombosis of the feeding artery and sac and/or pulmonary infarction.21 Rates of pleurisy are often higher in patients with feeding vessels measuring greater than 8 mm. Postprocedural complications related to systemic arterial embolization of clot, air, or the embolic device occur in less than 2.3% of cases and may manifest as TIAs, angina, or bradycardia.22
With regards to treatment follow-up, patients are followed longitudinally, usually through their HHT center. In the immediate postoperative period, expected physiologic and symptomatic changes are evaluated through the use of pulse oximetry and clinical observation.23 In most patients, reported immediate clinical and radiographic outcomes following embolotherapy include reduced flow across the lesion on radiographic imaging and improvement of oxygenation and symptoms such as dyspnea. Long-term benefits include decreased risk of ischemic stroke and cerebral abscess formation.15,24
The optimal regimen for follow-up is currently unknown, as more frequent follow-ups raise concerns for radiation exposure. Patients are initially seen 3-12 months at the clinic to monitor clinical improvement, including symptoms and oxygenation, and evaluate the status of the coils and feeding vessels through multi-detector contrast-enhanced chest CT with 1-2 mm thin slice formatting. Imaging findings consistent with treatment success are reductions in diameter of the draining vein, a minimum of 70% reduction in sac size, and lack of contrast enhancement. Non-contrast CT-imaging is then obtained every 3-5 years following the initial visit, unless the patient’s symptoms change and warrant additional surveillance.23
Recanalization has been estimated to occur in 10-25% of cases, with rates purported to be higher in pediatric patients, and is evidenced by findings of draining veins consistent in size when compared to preprocedure measurements and unchanging soft tissue masses associated with coils on imaging.2,6,14-15,25-28 The risk of reperfusion through recanalization of the embolized lesion is dependent upon angioarchitecture, coil-to-sac distance, coil number, and feeding artery diameter.1,21,27-28 A study by Kawai et al. reported that time-resolved MRI is more sensitive and specific than unenhanced CT when assessing for residual flow and may provide a more accurate diagnosis of reperfusion during follow-up than current methods of imaging.29
Further evaluation through pulmonary angiography is recommended for patients who present with worsening clinical features and radiographic findings, as these may be signs of recanalization or the development of new lesions.15,28
Although rates of permanent occlusion have been reported in the majority of patients undergoing embolization therapy, increased rates of patency, recanalization, and development of new lesions have served as obstacles in the successful treatment of PAVMs within the pediatric population. This has made the development of guidelines for the diagnosis and management of HHT in pediatric patients difficult and evidence for screening children has been deemed to be lacking by expert panels.23 Overall, pediatric patients have been reported to have much lower rates of neurological complications from PAVMs when compared with adults, especially those without clinical manifestations of disease.2,12,25,30 As lesions are thought to grow throughout puberty and the rate of reperfusion due to the development of secondary feeding arteries may be higher during this time, recommendations exist to delay screening and treatment of PAVMs until after the primary period of growth in childhood.2 However, although this approach may allow for the use of fewer recurrent angiograms and interventions, overall, more research is needed to evaluate the hemorrhagic and neurological outcomes of delayed intervention in asymptomatic and symptomatic HHT pediatric patients.2
Amplatzer Vascular Plug (St. Jude Medical, St. Paul, MN)
The authors have no potential conflicts of interest with respect to the research, authorship, and/or publication.
The patient and family referred to in this video article have given their informed consent to be filmed and are aware that information and images will be published online.
We would like to thank our patient for her contribution to medical education. We would like to thank the faculty and staff of Yale New Haven Health for their courtesy and expertise during the filming process.
- Pollak JS, White RI Jr. Distal cross-sectional occlusion is the ‘‘key’’ to treating pulmonary arteriovenous malformations. J Vasc Interv Radiol. 2012;23(12):1578-1580. doi:10.1016/j.jvir.2012.10.007.
- Balch H, Crawford H, McDonald J, O'Hara R, Whitehead K. Long-term treatment outcomes of embolotherapy in pulmonary arteriovenous malformations in children with hereditary hemorrhagic telangiectasia. Ann Vasc Med Res. 2017;4(4):1064. https://www.jscimedcentral.com/VascularMedicine/vascularmedicine-4-1064.pdf.
- Khurshid I, Downie GH. Pulmonary arteriovenous malformation. Postgrad Med J. 2002;78(918):191-197. doi:10.1136/pmj.78.918.191.
- Vettukattil JJ. Pathogenesis of pulmonary arteriovenous malformations: role of hepatopulmonary interactions. Heart. 2002;88(6):561-563. doi:10.1136/heart.88.6.561.
- Hosman AE, de Gussem EM, Balemans WAF, et al. Screening children for pulmonary arteriovenous malformations: evaluation of 18 years of experience. Pediatr Pulmonol. 2017;52(9):1206-1211. doi:10.1002/ppul.23704.
- Meek ME, Meek JC, Beheshti MV. Management of pulmonary arteriovenous malformations. Semin Intervent Radiol. 2011;28(1):24-31. doi: 10.1055/s-0031-1273937.
- Engelke C, Schaefer-Prokop C, Schirg E, Freihorst J, Grubnic S, Prokop M. High-resolution ct and ct angiography of peripheral pulmonary vascular disorders. Radiographics. 2002;22(4):739-764. doi:10.1148/radiographics.22.4.g02jl01739.
- Jaskolka J, Wu L, Chan RP, Faughnan ME. Imaging of hereditary hemorrhagic telangiectasia. AJR Am J Roentgenol. 2004;183(2):307-314. doi:10.2214/ajr.183.2.1830307.
- Gossage JR, Kanj G. Pulmonary arteriovenous malformations: a state of the art review. Am J Respir Crit Care Med. 1998;158(2):643-661. doi:10.1164/ajrccm.158.2.9711041.
- Guttmacher AE, Marchuk DA, White RI Jr. Hereditary hemorrhagic telangiectasia. N Engl J Med. 1995;333(14):918-924. doi:10.1056/NEJM199510053331407.
- Haitjema T, Disch F, Overtoom TTC, Westermann CJJ, Lammers JWJ. Screening family members of patients with hereditary hemorrhagic telangiectasia. Am J Med. 1995;99(5):519-524. doi:10.1016/S0002-9343(99)80229-0.
- Shovlin CL, Letarte M. Hereditary haemorrhagic telangiectasia and pulmonary arteriovenous malformations: issues in clinical management and review of pathogenic mechanisms. Thorax. 1999;54(8):714-729. doi:10.1136/thx.54.8.714.
- Pierucci P, Murphy J, Henderson KJ, Chyun DA, White RI Jr. New definition and natural history of patients with diffuse pulmonary arteriovenous malformations: twenty-seven-year experience. Chest. 2008;133(3):653-661. doi:10.1378/chest.07-1949.
- Faughnan ME, Lui YW, Wirth JA, et al. Diffuse pulmonary arteriovenous malformations: characteristics and prognosis. Chest. 2000;117(1):31-38. doi:10.1378/chest.117.1.31.
- Trerotola SO, Pyeritz RE. PAVM embolization: an update. AJR Am J Roentgenol. 2010;195(4):837-845. doi:10.2214/AJR.10.5230.
- Ference BA, Shannon TM, White RI Jr, Zawin M, Burdge CM. Life-threatening pulmonary hemorrhage with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia. Chest. 1994;106(5):1387-1390. doi:10.1378/chest.106.5.1387.
- Swanson KL, Prakash UBS, Stanson AW. Pulmonary arteriovenous fistulas: Mayo Clinic experience, 1982-1997. Mayo Clin Proc. 1999;74(7):671-680. doi:10.4065/74.7.671.
- Thabet A. Pediatric pulmonary arteriovenous malformations: clinical manifestations and embolotherapy [thesis]. New Haven: Yale University; 2004. https://elischolar.library.yale.edu/ymtdl/3243.
- Hsu CCT, Kwan GNC, Evans-Barns H, van Driel ML. Embolisation for pulmonary arteriovenous malformation. Cochrane Database Syst Rev. 2018;(1):CD008017. doi:1002/14651858.CD008017.
- White RI Jr, Lynch-Nyhan A, Terry P, et al. Pulmonary arteriovenous malformations: techniques and long-term outcome of embolotherapy. Radiology. 1988;169(3):663-669. doi:10.1148/radiology.169.3.3186989.
- Narsinh KH, Ramaswamy R, Kinney TB. Management of pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia patients. Semin Intervent Radiol. 2013;30(4):408-412. doi:10.1055/s-0033-1359736.
- White RI Jr, Pollak JS, Wirth JA. Pulmonary arteriovenous malformations: diagnosis and transcatheter embolotherapy. J Vasc Interv Radiol. 1996;7(6):787-804. doi:10.1016/s1051-0443(96)70851-5.
- Faughnan ME, Palda VA, Garcia-Tsao G, et al. International guidelines for the diagnosis and management of hereditary haemorrhagic telangiectasia. J Med Genet. 2011;48(2):73-87. doi:10.1136/jmg.2009.069013.
- Donaldson JW, Hall IP, Hubbard RB, Fogarty AW, McKeever TM. Peri-procedural complications associated with transcutaneous embolisation for pulmonary arteriovenous malformations: a systematic review and meta-analysis. 10th HHT Scientific Conference, Hematology Reports 2013; (Suppl 1):34–35
- Faughnan ME, Thabet A, Mei-Zahav M, et al. Pulmonary arteriovenous malformations in children: outcomes of transcatheter embolotherapy. J Pediatr. 2004;145(6):826-831. doi:10.1016/j.jpeds.2004.08.046.
- Lee DW, White RI Jr, Egglin TK, et al. Embolotherapy of large pulmonary arteriovenous malformations: long-term results. Ann Thorac Surg. 1997;64(4):930-940. doi:10.1016/s0003-4975(97)00815-1.
- Woodward CS, Pyeritz RE, Chittams JL, Trerotola SO. Treated pulmonary arteriovenous malformations: patterns of persistence and associated retreatment success. Radiology. 2013;269(3):919-926. doi:10.1148/radiol.13122153.
- Pollak JS, Saluja S, Thabet A, Henderson KJ, Denbow N, White RI Jr. Clinical and anatomic outcomes after embolotherapy of pulmonary arteriovenous malformations. J Vasc Interv Radiol. 2006;17(1):35-45. doi:10.1097/01.RVI.0000191410.13974.B6.
- Kawai T, Shimohira M, Kan H, et al. Feasibility of time-resolved MR angiography for detecting recanalization of pulmonary arteriovenous malformations treated with embolization with platinum coils. J Vasc Interv Radiol. 2014;25(9):1339-1347. doi:10.1016/j.jvir.2014.06.003.
- Giordano P, Lenato GM, Suppressa P, et al. Hereditary hemorrhagic telangiectasia: arteriovenous malformations in children. J Pediatr. 2013;163(1):179-186.e3. doi:10.1016/j.jpeds.2013.02.009.
Table of Contents
- Informed consent
- Sterilely prep and drape patient’s groin
- General Anesthesia (minor)
- Right common femoral vein is punctured under ultrasound guidance
- Use great saphenous vein as landmark in place of fluoroscopy
- Identified as placement of the wire directly to the right of the spine on imaging
- EKG monitor used to check for ectopic beats upon entry into the heart
- Positioning was considered accurate based on the pressure readings
- Pressure was recorded in the right atrium (11/8 with a mean of 9)
- Using the curved stiff back end of the Bentson wire, the catheter was then advanced into the right ventricle
- Pressure was recorded in the right ventricle (23/6 with a mean of 11)
- Distal end of the catheter was manipulated into the pulmonary artery
- Pressure was recorded in the pulmonary artery (22/13 with a mean of 17)
- Heparin 3000 units were administered intravenously
- Contrast injections with digital imaging over the left lung
- Right anterior oblique projection
- The left lower lobe contained one small PAVM previously discovered by CT (feeding artery 2 mm in diameter)
- Second lesion in the middle of the lower lobe (not suitable for embolization due to size)
- Based on size and location, feeding arteries determined to arise from the left lower lobe anterior branch
- Curved stiff back end of the Bentson wire used to return to the right pulmonary artery for angiography
- Left and right anterior oblique projections
- One simple lesion was appreciated at the right lung apex (feeding artery 2.5 mm in diameter)
- A small lesion at the right lung base (not suitable for embolization due to size)
- Pigtail catheter was exchanged over a Rosen wire
- 90 cm long 6-French sheath with a coaxial 125 cm long Berenstein catheter
- Allows access to the right upper lobe PAVM
- Consists of a Nitinol mesh
- Catheters manipulated into left pulmonary artery
- Coaxial catheter system advanced into first feeding artery within anterior lower lobe (diameter 1.7 mm), and eventually, the sac
- Location confirmed with contrast injection
- PAVM embolized with 4 mm AVP4
- Occlusion confirmed via angiography
- Cathers and sheath are removed
- Hemostasis is achieved at puncture site with manual compression 5-10 minutes
- 6-12 months, classically for repeat CAT scan
- Because patient is a minor and AVMS are relatively small, may be less agressive getting CAT scans
- 3-5 years (unless planning on getting pregnant)
So, my name is Jeffrey Pollak, and I'm the director of our Hereditary Hemorrhagic Telangiectasia Center here at Yale, which was founded by my predecessor, Dr. Robert White, as the first one internationally. Uh, and as such, we see many patients and their families with this condition.
People with this condition have a high incidence of something called pulmonary arteriovenous malformation, and what that is is an abnormal connection between the arteries and the veins in the lungs. Um, this, uh, this condition can predispose people to certain complications. Uh, and the most worrisome is the lack of the filtering activity the lungs. So, when, uh, if people develop small clots, they can migrate to the lung arteries, and normally be trapped by normal - by the, uh, precapillary level in normal lungs. But if someone has an abnormally large connection between an artery and a vein in the lungs, uh, a particle or a small clot can migrate through, and now lodge in a systemic artery, having gotten to the left - to the pulmonary veins, now come to the left heart and get, uh, pumped out by the heart into the systemic arterial circulation. And most worrisomely, that may lodge in a brain vessel, where it could stop flow and cause an ischemic stroke. Of course, they are also predisposed to bacteria getting through, and that can cause abscess formation. Uh, and if they are numerous enough or large enough, they can, uh, produce respiratory symptoms, because you're letting low-oxygen blood migrate through the lungs without ever seeing the function of the lung. And that can cause shortness of breath and related symptoms, although most patients do tend to tolerate the lower oxygen level pretty well. The last issue that these patients may suffer is that these abnormal vessels may spontaneously bleed. So, patients can develop a hemorrhage with hemoptysis, or coughing up of blood, or hemothorax, where the blood accumulate between the lung and the chest wall.
Um, so, the patient we're going to treat today is a 14-year-old who had a family history, on her mother's side, of this condition, and she herself has this condition as well, uh, on both clinical evidence and genetic testing. Alright, so there are 3 well-known genes for HHT. 2 are prevalent, and then there's a couple of others that are a little less well described at this time. So, once we know a family's genetic variance, we can test very young children, infants, for this condition. And then we will follow them for the potential problems of this cond - of this inherited disorder. So, one of the problems that I mentioned is pulmonary AVM, uh, and, uh, at age 14 or so, which is what our patient today, that's her age, we will screen for pulmonary AVM. At a younger age we will, uh, we will tend not to screen for it, other than just oxygen saturations, which, uh, through pulse oximetry at a pediatrician's office, because anyone who has a large enough one will show up that way, but small ones will not. Nevertheless, we know that small ones in young children do not cause the problems that they cause in adults that I mentioned before. Only larger or more numerous ones will cause those problems.
This, of course, is our standard here at this HHT center, but that is not necessarily the standard at other HHT centers around the world. There isn't always consensus about exactly the right way, but this has stood us in pretty good experience here. Alright, we've not really had significant problems in following this pattern of screening here. Um, just since I'm talking about screening in the HHT population, we will screen in infancy for one of the other problems they can get which is brain arteriovenous malformation. And the problem with those, of course, is they can bleed. And that can happen at an earlier age, so we will screen for that with a brain MRI, even in infancy.
But to come back to our patient, she's now 14, and she had screening for this study - oh, excuse me, for pulmonary AVM. And the way we screen for that is a contrast echocardiogram. So, that involves an ultrasound of the heart during injection of agitated saline, where there's a small amount of air introduced into it, and that will mix very vigorously with the saline, and that creates microbubbles, which show up on ultrasound. And they should only show up in the right side of the heart on an ultrasound. They should not show up on the left side, um, in any significant numbers. There is a normal variation where they can happen, where small numbers can show up in up to about 20 to 30% of the, uh, the "normal", in quotes, population. But if it's, uh, if we see any significant numbers, we know that the patient likely has pulmonary AVM, and then we follow that - pulmonary AVM, again, being pulmonary arteriovenous malformation - we then would follow that with a chest CAT scan to look for any significant-sized ones.
Now, tiny ones we do not treat the way we're going to treat today. We just treat them with antibiotics, before procedures that may produce a bacteremia, because we know we don't want a large load of bacteria escaping through that may lodge in a brain vessel, and cause a brain abscess. Of course, that'll be indefinitely, for the rest of the patient's life. The procedure we're most worried about, actually, is dental work. Even dental cleaning, because that has a proclivity to produce a large bacteremia.
But larger ones can let clot-like material get through, right, um, and small clots that may develop in a leg vein that are totally, uh, non-significant in another population can be quite significant in this population if they travel through a pulmonary AVM. And as we age, those are more likely to happen. And so these are what may be called as asymptomatic pulmonary emboli in the general population, but may not be asymptomatic in this population, because they can migrate through the pulmonary AVM.
So, this patient had a CAT scan, and has several tiny, very small pulmonary AVMs, that are not worth going in and treating the way we're going to treat today. But she had at least 2 that we saw on the CAT scan that are just barely of a size that we worry can let something migrate through that could cause an ischemic - lack of blood flow - stroke. Alright, uh, so, one of them is in the right upper lobe, and that had about a 2.5 mm feeding artery. And the other one is in the left lower lobe, and that had a little over 2 mm feeding artery. The threshold for letting something migrate through the pulmonary AVM that may cause an ischemic stroke is in the range of 2 to 3 mm. So, the smallest size of the abnormal vessels uh, is in the range of 2 to 3 mm. And that is someone who we would like to go in and block the pulmonary AVM.
So, the procedure today is called a pulmonary AVM embolization. It’s preceded by the angiogram, a pulmonary angiogram, to identify the AVMs on angiography best. And then we would place a catheter into the artery feeding the AVM, and block it with some type of mechanical agent. So, the mechanical agents that are available to us consist of embolization coils, and these are wire threads typically with, um, uh, um, polyester threads along the wires. And they're shaped in helices when they're resting, but, you know, they can be placed through thin catheter in a stretched-out format, and then they'll form in the helix when they release at the tip of the catheter in the target vessel. Another agent we can use is, uh, are, um, what's called an Amplatzer vascular plug. And this is a Nitinol mesh that is compressed as it's delivered through the catheter, and then when it's released, it expands into a spindle-shaped structure. There's 2 different forms: one is more cylindrical, and one is shaped like 2 Hershey Kisses connected to each other. Alright, the third type of agent, which is newer, is called a microvascular plug. And that agent doesn't have as long-term data at this point, but seems to be pretty efficacious also. And what that is is a thin - a framework of Nitinol metal with a plastic cover on it, really a Gore-Tex, polytetrafluorethylene, cover on it, and it acts like a windsock. So, when you place it in the vessel, it'll block the flow through it.
Alright, and the purpose of this, again, is to block the pulmonary AVM, prevent anything from migrating through it. And it should also make the PAVM, over time, clot up, and therefore the risk, if it were to grow larger, of spontaneous bleeding goes away as well. This is not going to treat all the other little tiny ones because of- someone with HHT is very likely to have multiple tiny ones, and we know she has other tiny ones on her CT scan. Those we will watch, and, over her - she will require surveillance for, really, the rest of her life. And we'll watch them over time, and if they grow larger, which, they have a very slow growth rate, then we will treat them in the future, in this method. Otherwise, they just receive antibiotic prophylaxis before procedures prone to produce bacteremia.
Once again, this patient, though, is purely through screening. She's asymptomatic from her condition at this time. Other than occasional nose bleeds, which is another thing that patients with HHT actually get. So, that's the most common symptom in HHT. 90%, by their twenties, will have nose bleeds.
So, the name of this procedure is pulmonary angiography and pulmonary arteriovenous malformation embolization. Uh, the indication in this patient is that, on screening, she was found have pulmonary AVMs that are large enough to treat by embolization, therapeutic embolization.
The steps of the procedure will be, uh, that we will - The patient, since she is a minor, and 14 years old, she'll be done under anesthesia. Normally we would not do this in an adult under anesthesia. It could just be done with IV moderate sedation to relax people. We typically will do a femoral vein approach. So, after cleaning up with sterile liquid, the femoral vein area, the right - typically we go in through the right groin, uh, we will puncture the vein there. We will thread a catheter up under fluoroscopy, which is real-time X-ray vision, uh, into the right side of the heart and then across the right side of the heart, and we'll measure pressures in the right side of the heart, and across the right side of the heart into the pulmonary lung artery, we'll measure pressure is there, as well, since patients with the condition HHT can have a higher incidence of what's called pulmonary hypertension, abnormally high pressure in the lung artery. We will then inject contrast, radiographic contrast or X-ray dye, into one lung, the left lung, typically, first, to outline where the sizable lung AVMs may be that we should be putting our catheter in later to block. We will then move our catheter to the other lung, the right pulmonary artery, and inject contrast or X-ray dye there, to outline any pulmonary AVMs on that side that are large enough to subsequently place a catheter in to block that.
Once we have our road map angiographic pictures, we will then switch out that type of catheter for the different type of catheter that we use to select the artery into the pulmonary AVM. Once we’re an appropriate location, we like to be very close to where the actual artery-to-vein connection is located. We will then introduce something through the catheter to block up that pathway.
So once we have blocked up uh, one of the lung arteriovenous malformations, we will inject contrast to be sure it's adequately occluded. Then we will move our catheter to where the other one, or ones, are located, and do the same thing with those. At the end we will, uh, just pull out our catheter, hold pressure on the femoral vein, uh, and then the patient has to lie in bed for several hours.
Of course, we do take certain precautions during the procedure to prevent clots forming around our catheters that, of course, could migrate through the pulmonary AVMs. We will give some anticoagulation, blood thinners. Not a full dose, but a moderate dose to try and prevent that. And we will also - while we do the procedure under complete sterility, we also play it safe by giving an antibiotic.
The, uh procedure is an outpatient procedure. The patient will be at bed rest for approximately 3 hours afterwards, then be able to arise, walk around, and go home.
Alright, so the first thing we're going to do is uh, puncture the right common femoral vein. And we can do that under ultrasound, and we can use the great saphenous vein as a landmark for it on ultrasound, thereby avoiding fluoroscopy in this area, to confirm where we are that way. So, I'm just using ultrasound to look at the common femoral vein, right there. And then I’m going to puncture under ultrasound guidance.
Okay. So, we'll advance our wire through now. We'll do a quick look, and that looks like it's in the IVC. Alright, so, on the right side of spine is the inferior vena cava, so we know the wire is in the correct location.
Alright, so I'm just going to make a small incision, so we can get our catheter in place later. Okay. Now, we have our dilators to upsize from this thin access system to the slightly larger catheters we'll use for the procedure. If you could put that away. All our sharps go into a foam on the back table, so we don't have anyone getting stuck. Do we have our pigtail on the table?
So, um... The antibiotic's given, correct? Alright, in one moment I'll ask you to give the heparin.
Alright, so we're going to go with our pigtail catheter. Right, and you can see these little side holes here that'll diffuse a high-pressure injection, so the catheter will not whip that much inside. Okay. I should introduce Dr. Elias, who's my assistant. One of our fellows, finishing up the end of this week.
So, we're threading the 5 French catheter over wire, into the blood vessel. It's an interesting thing, um, if you go back to the early days of angiography, it was a big issue how to figure out how to get a catheter into a blood vessel. And then there was a landmark, uh, invention back in the '50s, by a Swedish radiologist named Seldinger. You put a needle in, you put a wire through the needle, you get the needle out, and you put your catheter over wire. But before that, for decades before that, it was actually a struggle to figure out how the best way to get a catheter into a blood vessel.
Look, they’re - the way they're positioned, I can see their EKG. Because when we move our catheter through the heart, we can cause some, uh, ecto - ectopic beats. And we need to know that. So, we need to adjust our catheter if we have too many of those. Alright, so, we'll get that out, we'll get our pressure here. This we don't need to do under water, because it's a multi-side hole. We shouldn't really let air get sucked in. So, when we do this procedure, it's, uh - we have to be super cautious about not letting any air get injected, because that could become a paradoxical embolus, something that migrates through the pulmonary AVM just the way a small clot could.
So, we are now obtaining pressures in the right atrium. And we’re going to record that. And we have 11... 8, 9. Let's just make sure our... Looks like we're reasonably positioned with our... with our deucer. Are you - we're not low, do you think? Okay, I think we're pretty good in terms of the right atrial position. Alright, so, 11/8/9, I'm going to take. 11/8/9.
You have the curve? Looks good. So, we'll use the curved back end of the wire to stiffen up the catheter, and turn it from the right atrium to the right ventricle, which is a right-angle turn. The catheter is a straight catheter, wouldn't do it on itself - by itself. So, you see, this can angle it towards - from the right atrium to the right ventricle. We might need a little bit more of a curve on it. Oh, maybe not. So now, it should be in the right ventricle, uh, and our ectopy scale... We're doing okay, we don't have much. Looks like there's not much cardiac irritability.
And so now, we're going to obtain a right ventricular pressure. Have to be careful of the air bubbles, there. So, 23/6/11. So, you can see the red numbers, and you can see the, uh, the waveform below that. 22/6/11, we'll take. No. 23/6/11, we'll take.
Now we're going to advance our catheter into the pulmonary artery. We're hitting the end of the table, so we need to move things up. Alright, now we're in the pulmonary artery, and catheter distal end is actually in the left pulmonary artery. So, we'll obtain another pressure here. So, it's 21/13 - 22/13/17. 22/13/17. Okay.
Right, now we're going to do a test injection. Okay.
Alright, and then we're going to hook up to our injector. So that was the catheter in the left pulmonary artery. We're going to hook up to our power injector, to be able to inject quickly in the fast flow of the left pulmonary artery. Forward, please. Back, please. Towel. Forward. Alright, we have no bubbles, we look good.
So, roughly half the cardiac output will go to each lung, correct? So we have to inject at a reasonable speed in order to, uh, fill the vessels with contrast, or X-ray dye, and visualize these - any of the abnormal vessels well.
You want to go with the heparin?
You can give that now, 3000.
And then we'll make sure our field is set, because, you know, her lungs will expand, and I don't want them to come off the field of view at this point in time. The endotracheal tube looks fine, right, above the carina. Thank you.
Alright, I think - you can, uh, if you can just hold for another moment - you know, you can already see we need to demag a little bit, right, so we'll raise the table up to do that. Okay, you can let her breathe while we get everything else set up, okay.
Alright, so we're going to inject, um... Let's go - I think we'll go our usual, 12/4/18, make a 0.3 rise. Okay, hold. Alright, and Alyssa, you go ahead. Stop. You can, you can breathe her.
Alright, we'll review our images, we'll clean them up a little bit. Okay, so, um, we can see in the left lower lobe over there is a small pulmonary arteriovenous malformation. It's not large, but definitely that could permit a small clot to get through it, that could potentially cause a stroke. And I've seen that happen in a couple of people in their twenties, so it really is, it can be quite serious. There's another tiny pulmonary AVM in the middle of the lower. That's too small to block. That - maybe in 10 years it'll grow and may need to be blocked, but that is too small at this time to block.
Alright, let's see if we, uh, have the best route to it there. So that's going to - that's probably an image we should store, right. Well, let's look at it unsubbed. Maybe we'll look at it on landscape, too, and work it backwards to see where the exact originating vessel is to it. Looks like it's coming from up there, it almost... It's odd, because in the CT scan we know it's the left lower lobe, but here it almost looks like it's a lingula artery supplying it. You know? We'll have to explore it. There may be a little bit of overlap. Alright, so let’s store... Could it be coming from the low - It could be coming from the lower branch, actually. It could be coming from that left lower lobe anterior branch. Right? Yeah, it could be, alright. So, let's store that. So, I can store some reference images for myself over there that I can review more easily than just reviewing the entire sequence of images. Uh, let's go back to the proper mask.
And just to review, you’ll see there's an artery that comes down, fills it. And then there'll be - that's the vein coming back. But you see that straight oblique line going back up. So, that's an early filling vein. That may be a little telangiectatic type of AVM, over there in the mid-lung linugla. Maybe. Alright, so I think we have this lung sorted out.
While we're here, let's take a tape measure and we'll figure out what length guide catheter we'll need. So, this is a 100 cm catheter. And that's, uh, 35. So, we'd need 65, it - That only gets us to the left main, not to a branch. So, I think we'd have an issue, uh, but we could potentially go with the 690 and the 125. So, I may go with that, because the selection, I don't think, will be that hard.
Alright, so now, we're going to go to the right side, so let's get the back end of the Bentson wire to direct ourselves. So, the left pulmonary artery is the natural continuation of the left main - of the main pulmonary artery. The right pulmonary artery is a right-angle turn. So, we have to move a straight catheter across a right-angle turn into the right pulmonary artery to look at that side now.
Alright, we call in our image, so we, uh, minimize our radiation exposure. We're also on low-dose radiation for the time being, so very low-dose fluoroscopy. We have different flavors we can use for that.
Could I see the curve on that? So, we might need to have this a little tighter, and somewhat, you know, smaller like this - than this. Alright, so the back end of this wire has a curve on it and lets us angle the 90 degrees over into the right pulmonary artery.
Okay, we'll see that fine.
We're going to hook up again, please. Same rate? Uh, yes it'll be the same rate and volume. Forward. So, we hook up to our pow - Back. We hook up to our power injector again, so we can deliver that fast rate of injection, that gets closer to the natural flow of the vessel. Forward. We're clear, no bubbles.
We'll start with this oblique. Although a frontal may turn out to be very good for the right upper lobe. But we'll see. This oblique often is not bad as well. So, we'll do the same thing. We're going to ask you to hold the breath in when we're all out, okay.
Okay, Alyssa, are you ready for the injection? Yes. Okay, so we can hold the breath. Stop. Okay, we can let her breathe naturally, now.
This one looks a little richer, huh. So, and there's something - Is there something down the right lower lobe, there? I'll have to look a little closer at that. So, we can see, uh, in the right lung, if we go up, we can see there's a vessel that goes to a little tortuous vessel right at the apex of the lung up there. And then you see the vein coming back. So, you see more faintly the artery, and the vein is a little more dense in this little later-phase image. That's an arteriovenous malformation of the apex of the right lung.
And I've got to get a little better look at what's going down at the base, there, because there's another little something down here. Ah, that could be an artifact. Let's look at it unsubbed. And then there's a little stain out there. See, there's something there before. So, it could just be a, maybe a little rib, or something. I don't know. Might need to do another view to sort that out better.
Alright, let's, uh... Let's try a bit of an RAO, we'll just make sure we're not missing something at the right base. Okay. Can you do that breath hold for a moment, so I can just see my field of view? Thank you. Okay, you can breathe her.
Alright, so, let's do another injection here. You're stepping out for this one? Okay. You figured out how to - You put a clamp on it, or something? Yeah, it's fine. She's not - her breath is stable. Stop. You can let it go at whatever your machine setting is.
So, we did this second one because I had a little concern that there was something at the lower lung. There is a faint stain there. I suspect it's a very tiny lesion that, again, is not going to be worth us to block, to embol - therapeutically embolize. But we have a very nice view of the right upper lobe AVM on this. But we could take a little closer look. We may catheterize to take a little closer look at that right lower lobe, down here.
This actual view may lay out the catheterization better, huh? For the upper lobe. Maybe even for the lower lobe, oddly enough.
I'm going to try the, um... Can you give me the the 6 guide catheter, please? I'm going to try that system. Yeah, and I'm going to measure that, and see if I need the 125, or I can get away with the 100. I think I'm going to need the 125 from past experience, but we'll see. So, you know, the width of her pulmonary arteries is not as large as a full adult, so this may work fine. And then if we could just lay that out over the table. Let the water run out into the bowl.
Alright, so, that's, uh, 61. And, so it's like, uh, 61 and 35. That's 96. I don't think it'll be enough. So, let me have the 125 Merit and a 6 French sheath. So, one of the reasons I also want to use this system is I thought the 6 French inner catheter from the 8/6 Lumax - white Lumax guide catheter might a little big for her. So that's why I also wanted to do this. Now, this catheter should fit through that 6. We'll find out in a moment. Okay, thank you for leaving that in the bowl. That way we won't have a mess all over the place.
Alright, so we're using a double catheter system, here. Uh, and that gives us more stability in the lungs. You have to realize that the lungs are moving, and you're also going through the heart, so you have the added motion of the heart. And so that means that can kind of move your catheters back and forth. And so, to have 2 catheters actually gives you more stability in there. Can we have the 260 Rosen, please?
Make me look bad.
Alright, so we're going to - once we get a sheath in, we'll hook up the sheath drip to that, correct? Also, the tighter the system, the less chance, you know, blood can migrate into it and clot formation. Alright, so this is a longer wire than we used before. It's to exchange one catheter to another. A set of catheters, in this case. Maintaining our access into the right pulmonary lung artery. Alright, I'm going to let you take over while I, uh, I hold here. You need a towel to put the back end of the wire underneath?
Uh, yes please.
Okay, and I have wire. I'll wipe and loop, and we're going to go with the 6 French sheath, next.
One problem with this system is the pigtail won't - If you wanted to do a global pulmonary angiogram, the pigtail won't quite be far enough out.
You can pull the wire. I'm holding the front tightly.
Okay, we're going to put our sheath in. Okay, we're going to keep our wire in, of course, because we have to get our selective catheters to embolize in place. So, the sheath is just an introducer into the femoral vein, so we don't have to worry about moving directly through the vein with our selective catheters. And we didn't put it into begin with because I wasn't sure what size sheath I was going to use.
Once again, we have to be very cautious of any air bubbles. We're going to let the sheath drip go in one moment. It's open to the syringe, so we can just let the sheath drip, uh, go. Thank you. Alright, and you can let it be a slow drip to the patient, now.
So, once we have a wire in, you know, the- This doesn't work, so we have to do this. If you could just, um... Just get the loop further away. Great. Now we'll just stabilize our sheath so it doesn't slide in and out as we're making motions with our catheter through it.
Okay, now we're going to go with our coaxial catheter system, our double catheters. Okay. Now, with one hand you're going to have to hold the wire, the other hand, you're going to have to hold the 2 of these as a unit, so I don't slide one over the other, right. Because we don't have a - We didn't use a Y-adapter on it, right?
Okay, we're having some resistance. Let's move this catheter a little further in, see if that helps. Counter 2 on the wire, please. Alright, so we're having... It's not wanting to go. Why are we having resistance? Okay, it's going now. Now let's get the guide in. Okay, it's going. I don't know why we had resistance before, but it's going very easily now.
Alright, so now, we're going to, uh... So, this is an end-hole catheter. And it could suck air in around the wire as we pull it out if it's up again - if the tip is up against the wall, so we put it underwater to prevent that. Okay. Okay, now we have blood return. Let's go back into this 40-degree, see if that helps us. Alright, so we're going to have to come back. I don't like having that air in there. Good, better.
So... This doesn't have the multi-purpose shape of the other one. If we have trouble, we'll switch to the 8. But I thought keeping to a slightly smaller size in the 14-year-old might be preferable. Okay. Okay, now we have to, uh... So, it's not quite reaching up there. Alright, so I think that's the vessel there.
I'm debating whether to use the Bentson wire to help us out a little bit. The front end of the Bentson wire. Okay. Because when I advance it, it walks past that, right. Alright, and you can see the origin of the vessel there. So, maybe take the Bentson wire... Let's, uh, let's take the Bentson wire, the front end, the soft end. But if I put a little curve, I wonder if it may actually tend to point there. That looks promising, right.
Alright, so you can see our catheter is moving up that - most on our right side, the patient’s more left side. That vessel going straight up is the one I believe is supplying the pulmonary AVM. And you can see we’re matching the catheters, matching that image. Right? So it looks like it's in the location of the artery feeding the arteriovenous malformation. We'll confirm that with some contrast.
Have to be able to aspirate, of course. Alright, we're getting return now, good. Alright, you can see, there's the AVM. Can you get a 5 mm AVP 4 ready for me? No no, a 5 mm AVP - Amplatzer vascular plug, version 4, 5 mm. So, we want to get a little more distal than that. We want to be right against the connection. So you see, we're right in the connection, right, of the AVM, there.
And now we're going to introduce something through this catheter that will plug up the pathway. So a 5 mm AVP 4. Alright, so this is a Nitinol plug. It's a single unit, but it looks like 2 Hershey's Kisses back to back. And we'll show you the actual plug. You can actually deploy it and retrieve it on the table here, so we can show you that. And this will block up through the bulk of metal, plus clot formation on, on the plug itself. Or within the plug itself.
So, this is the delivery system for the plug. It's a retrievable device, meaning it has a - it's connected on the back end to a cable that's screwed into it. And then you unscrew it to release it once you're happy with its positioning. So there, you can see the plug. What's a good surface? How's that? And you'll see it'll collapse into a catheter, or in this - you know, this is the casing to intro - the cartridge to introduce it into the catheter. Alright, and I flushed it with contrast. I want no air in the system, I don't want to introduce any air, I want everything wet. No air bubbles.
If you could make a flush hook-up there, please. Keep going. Okay, now Dr. Elias is going to advance the plug through our catheter. You want another towel to put that under? Yes, please. We'll confirm that we haven't migrated. I'm going to shift our position a little bit, like that. Maybe I'll go a little frontal to get it off the, um... Not too much, though, right? It separates the artery and the vein better if we're a little bit this oblique. I'll mag it up so we can see it best.
Okay, you're coming through. So, you can see that little dot. That little blacker dot. And you see 2 little blacker dots. That outlines the distal and the proximal ends of the plug. Keep going. Now unsheath it, by pulling the catheter back over it, from back here. Oh, you don't have enough room. Okay, so let's do it over here then. That's because we're using the 125 cm catheter.
Push forward on the plug a tiny bit. Good, keep going, unsheathing. Alright, so you can see the released plug there. I'm going to try and get it off the clavicle a little bit better. Alright. So, you can see the plug is released. It's held in the vessel by radial force. You oversize the plug to your estimated size of the vessel by 50 to 100%. I estimated this vessel size at about 2.5 mm, and this is a 5 mm plug. For this particular plug, you oversize 50 to 100%.
So, it looks good, we’re going to release it, because it's still connected to the delivery cable until we unscrew it from it. So, Dr. Elias is now unscrewing the delivery cable. I'm going to pull this back a little bit to separate the two more. And you'll see it release - Ah, and now you can see it's separated. So there's nothing on the back end of the plug now.
Now, this doesn't occlude immediately. It generally - it can take 5 to 10 minutes to actually occlude the vessel, but the experience with these plugs is excellent, they will eventually occlude.
I'm going to have to pull the guide, I think the guide - I'm glad I didn't go with the 8 system because it would have been too tight in there. Okay. So, I got the guide out of the feeding - you know, the more proximal feeding artery.
Okay, we have return. So, you can see there's still flow through that plug, but it... I'm highly confident that it will go on to totally occlude, with time. It's probably not worth spending that time now, probably during that time, we should go treat the other side.
Alright, so let's get our images up for the other side. So, my first guess is that the supplying vessel is not the lingula but truly the lower lobe, as it looked like - since the lesion did look like it was in the lower lobe anteriorly on the CT scan. So, I think it's going to the most anterior of the lower lobe, which is what we should try to select first. And if we're wrong, then we'll have to go try and select the lingula. And it would have to be crossing the fissure.
Alright, so... Generally we treat the right side first when we're going to treat bilaterally, because it's very - it's generally easier to get back over to the left than the right, because you don't have that right-angle turn issue, right.
That's a nice view of the plug in the frontal projection. And you can already see the flow through it is much slower. It barely is getting through. There was just a bare stain there.
Okay, so let's go back over to the left side. Okay, we're in the left lung now. I'm going to go this oblique. Back into the right anterior oblique projection. 38. Alright, now we're selecting off an upper lobe artery. And then when I go back to the right we may decide whether we search out that lower lobe and take a better look at the lower lobe or just forget about it, because I'm not too concerned. You know, that right lower lobe thing. But this is the most, you know, the 2 most important, clearly, are the... There's a tendency to select out the superior segment, which is where I think we are. Now that is going to the lower lobe. Okay, let's get our guide down a little bit, so we don't have to struggle there again. Now, this could be, uh, this could be in the vicinity of what we want.
No. So, but that may be one step lower than we need to be. The anatomy looks like it could be one step low - there may be one more anterior left lower lobe branch. Alright, so let's move our guide back a little bit. And then we move the 5 French inner catheter back a little bit.
Okay, now this is the vessel we need to try - to look at. Come back. Okay. There it is. We can see it, right. Oh, there's 2 things there. You see that? Let’s get our 6 guide in to help us. Let's get a better view of this. Alright, so you could see there's actually, uh, there's the small one here and some other tiny little thing over there. So, the bigger one is obviously more, the one in the corner. And that we definitely need to block, but you know, since we're there, we'll just probably block up both.
But you can see the smaller one that's closer to the catheter tip, and the slightly - the larger - still not large, but larger one, further down. Now we always want to block these close to the connection, so I want to get really further down onto that. Okay, there we are.
What do you think, a 4 mm here? The - This is, this is, uh... So this, in terms of the size of the catheter, was barely larger than the catheter. The catheter is 1.7 mm. So, it's going to be in the- So it's not going to be really much more than 2. You know, 4 would be close to twice the size. It would be certainly the 50 to 100%. So, I think an AVP 4, 4 mm. So, a 4 mm AVP 4, guys. And then we'll have to figure out what to do with that more proximal one. Alright, you know, while we're there, we should just take it so we don't have to worry about it 10 or 15 years from now.
So, this is the same device we used to block up the right upper lobe. It's just a slight - it's a 4 mm diameter instead of a 5 mm. Let's leave that connected, so that we can, uh, have everything flush - in the flush hook-up, right. Okay, flush. Okay, again, we avoid air that way. We have only fluid connections, all fluid connections. Because air migrating through a pulmonary AVM in a solid bubble can also go to a cerebral vessel and cause a vapor lock, and cause a stroke that way. Or, hopefully, it would dissolve in time and not cause a real permanent stroke.
You should be getting close, huh. Okay, there you go. So, we can see the 2 blacker dots outlining the distal and proximal ends. Why don't you unsheath it. Okay, go ahead, do what you've got to do. Okay, that looks pretty good. And it looks pretty stable to me. So, uh, you want to release it. So, if we didn't like the position, we could pull this whole thing out. This plug. Oh, okay, there it goes, and it's released.
Now, we're going to have to figure out - We may need to put - I don't know that we'll get into to the other one or not, or we're just going to go later, because this is a short feeding artery, and that's kind of off a side branch feeding artery, so we may have to just block across it.
Alright. Let's, uh - bowl? So, I prefer to use the plugs, if possible, because they seem to have a lower, uh, recanalization, or leak, rate. So it looks occluded with the coils, those threads of wire, and those have a higher incidence that later on they could reopen, have a leak develop through them. Whereas the plugs, the leak rate through plugs is extremely, it seems to be extremely low in the, uh, current published literature. And that fits with my experience as well, of course.
Alright, so I think we're just going to wind up putting another plug here, and, uh, should we go with another 4? Or another 4 - maybe a 5. Yeah. Do you have another 5 mm AVP 4?
Fill, yeah, drip away. Okay, let's go. You having a little trouble? Oh, you have to go here. Alright, so try and just pop it at the distal end and then uncover it. I wouldn't try to - Because you're going to perforate the vessel if you try to push it out beyond it, right. Good, so I wouldn't go any further. Okay, push it in a little - Uh, here let me... Okay, I know it's a little tight pushing it through, right. Okay, go ahead, try from there. We're back there. Okay. Oh, let's pull the whole thing back a little. Here, I'll pull this back. If you have to pull it into the catheter, so be it. Okay, how's that? Why don't you just release it there. Good. Okay. That's very nice. That looks good. Alright, you're released.
Okay. So, uh, the distal one looks like it's, you know, occluded pretty much already. The proximal will go on to occlude. I'm not too concerned. Okay. So let's start pulling things back, and maybe we'll take another look at the right side.
Now, let me have the, uh - Is this the Bentson or the Rosen?
That's the Bentson. The Rosen's here.
So, I'm going to need, um - I'm going to try - I have to get over to the right side with relatively str - you know, they're not very angled catheters. But, uh, with this, sometimes if you - you can flip yourself over with the, um, the front end of the Bentson, the soft end of the Bentson.
Oh, doing this, I should probably review, uh, what we want to look at in the right lung.
Well, first, maybe, we can just use the hook of the - this. Can you pull the wire back and try to advance it? Let me turn it to the right first. Go ahead, alright. Okay, go. Alright, you know what? Just - if it happens again, just let it go, maybe you can bounce us - oh. Okay, keep going. Keep going. Keep going. Alright, let me see if I can follow you a little bit. Come on, go, go, go, go - There we go, okay. And let me follow with the guide. Alright.
See, with a soft floppy catheter, you can let it buckle and help take you places. Problem is it, uh, pulled us back - There you go. Bowl here. Oh, you have the bowl? Alright. Nothing impressive down there. Nothing there, right, and, and this looks like it's probably the more lateral channel, correct? So, and that would be the one supplying it all the way to the edge of the lung, I would think, if there was anything - Again, I didn't - I thought it was just a little stain. Nothing major. Right, so, there's nothing there. This has got it - that's covering that entire corner. The other branch doesn't come into that corner. So, it was right over the, uh, cable. There's nothing there.
Then maybe we should just take a look at the right upper lobe, while we're here. We might need to front end of the Bentson for that, right. I may not be back enough. Alright, maybe we should just, uh, do a run. A hand run, right. That may - from this location, that may be good enough. You can drop the rate down to, um, 2 a second for the beginning, alright. Okay, yeah. Can you stop her breathing, please? Thank you - it's done, yes? No, 2 for the first, and everything else the same. Alright, okay, I'm going to do the run.
So, you see, it's completely blocked. You see the flow up to the plug, and then it stops. You can breathe her. So, just a little time, and it does occlude. So, here's the vessel that went up to the plug, over here. And then you can see the slow flow at the back end of the plug, but nothing through the plug or filling the AVM, so I think we're fine there. The vein still fills from her surrounding capillaries, so that's not surprising.
And then we could take another look at the left lung, if it's been enough time, you think? Although frankly, I'm not sure it's really worth it. We'll make a very brief attempt just to confirm occlusion on that side, but we're not going to spend a lot of time.
See, again, there's a proclivity to select out superior segment branches, which is what's happening right now. When you go on the left side, at least. So, we take the front end of the Bentson, we can probably just let it bounce down into the lower lobe. And there it bounces down into the lower lobe. We might even be in the correct branch, huh. No, we have to go one up. Let's get our guide in, to help - No. Secure our position. And now we're in this branch. No, didn't like that. And it popped us back into the superior segment. Alright. Let's have the Bentson, we'll try that one more time. Really wrapped up, huh. It's not quite a wrap, though.
Alright, so we're in the left lower lobe. I think we're in that anterior branch of the left lower lobe, now. Alright. Okay, um, can we, uh, can we just stop the breathing? I'm going to do one more, uh, run here. Thank you. Okay. Alright, so that looked good, so we're, uh, done. We'll have to just pull out and compress. We'll just review that. Thank you, you can breathe, I should have said that.
Alright, so you can see the 2 plugs, and there's - and you see the flow, the contrast up to the back of the... well, proximal one, and nothing beyond.
Okay. So now, we're just going to compress for, uh, a few minutes. Okay. Uh, and it's 12/12 on the, uh, or 12/10 on the Mac-Lab. So, we'll just compress for 5 to 10 minutes, uh, until the veins seal up the puncture into it. And then we'll have her on bed rest for 3 hours so I assume that will be until around 3- 3:20 or 3:30. And then we'll let her get up.
So, our follow-up, at this point, would be to see her in 6 to 12 months. And the classic follow-up would be to repeat a CAT scan to see if the AVMs have shrunk down. Because if they're blocked up, they should shrink down. However, you know, she's 14 years old, and there's a concern about, over her lifespan, giving her radiation exposure from a bunch of CAT scans over her life. So, I am trying to limit that, and very small ones- like, she had pretty small AVMs, I've not been of highly aggressive about getting CAT scans, uh... So, on her, with small ones where I think the chance of, even if there's a leak, that it wouldn't let a clot get through that's any size, I've been holding off and maybe waiting a little longer, maybe going out to the 5-year mark.
So, the classic would be 6- to 12-month follow-up CAT scan, and then every 5 years. Some people might drop it down to 3 years, another CAT scan, and certainly, you would want to reassess someone - Let's say she was 22, you blocked up one, and you saw her at 22.5, 23, and then she was going to get pregnant at age 25. You'd want to - you wouldn't wait 5 years, because pregnancy can enlarge the AVMs. So, you really need to know before someone gets pregnant, they should only have planned pregnancies. And you need to really kind of assess people before pregnancy, because the increased blood volume, and the hormonal changes, it can definitely enlarge the pulmonary AVMs, and there's a higher risk at the time of pregnancy.
So, uh, what we just saw is, uh, a 14 year old who underwent a pulmonary AVM embolization. We explained the reasons why we did that before. Uh, to prevent a paradoxical emboli, that can result in a stroke. Or, it doesn't really necessarily protect as much from paradoxical bacterial emboli, because still tiny pulmonary AVMs can remain that can cause that. That will require antibiotic prophylaxis. But it, overall, can decrease that risk , not eliminate it. Alright, and also, the risk of potentially hemorrhage, spontaneous bleeding, from one of these AVMs. And if there's larger numerous ones, the risk of the- of having, um, hypoxemia, low oxygen, and shortness of breath from that.
So what we used in this patient, uh, is Amplatzer vascular plugs, which is a device that's been around a few years now. And these are Nitinol mesh plugs that will expand when they're released from the catheter and occlude the vessel, right, and thereby prevent any flow through it that may cause, uh, these problems, and the AVM beyond it should go on to thrombose, or clot up.
So, the follow-up for this patient is - the next thing is, once these patients - once you meet these patients, really, they're your patients for life. They need to be followed longitudinally. Uh, and, uh, generally, since they have the underlying condition of hereditary hemorrhagic telangiectasia, it's best that they're followed through an HHT center, as we are here. So, for her, we would - I would like to see her in 6 to 12 months, and we'll do, possibly some imaging studies, or possibly not, depending upon my concerns about radiation exposure, uh, and then every 5 years thereafter.
Of course, the other part of this is that since it's a familial disorder, we have to check all the family members. And her parents are well-connected on that, and, uh, and are aware of that. So that's - that, of course, has happened in this family, which is how, of course, we found her, as well, since the parents were very on top of things, and made sure their daughter was screened for the presence of HHT, which she indeed had, and then for the potential manifestations of HHT, which can be silent, such as a pulmonary AVM, until a problem occurs.
Just to put it in perspective, if someone goes through life with a significant-sized pulmonary AVM, and you don't block it up, the rates of having a stroke from that vary in the literature, but it's probably, at the low end, 11%, but probably as high as 30 to 33%. So that really, I think, puts it in perspective, that over one's life span, this can be a significant issue.