Transcatheter Valve-in-Valve Implantation due to Severe Aortic Regurgitation in a Degenerated Aortic Homograft

From the Department of Cardiology, Rigshospitalet, Copenhagen, Denmark. The authors report no conflicts of interest regarding the content herein. Manuscript submitted March 5, 2009, provisional acceptance given April 30, 2009, and final version accepted May 4, 2009. Address for correspondence: Lars Søndergaard, Department of Cardiology B 2014, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. E-mail: lars.sondergaard@rh.dk

_______________________________________________ ABSTRACT: Transcatheter aortic valve implantation (TAVI) in severe aortic stenosis has proven to be a feasible and effective treatment modality for inoperable patients. Until now, neither aortic regurgitation nor degenerated bioprostheses has been an indication for TAVI. However, this article reports a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access options than the femoral arteries.

_______________________________________________

J INVASIVE CARDIOL 2009;21:E197–E200 Transcatheter aortic valve implantation (TAVI) has proven to be a safe, efficient new treatment option for inoperable patients with severe symptomatic aortic stenosis (AS). In 1992, Andersen and colleagues made an early attempt at transcatheter delivery of a valve in the aorta in a porcine model,1 and since then, two systems for aortic valve positioning have been introduced: the self-expanding CoreValve ReValving® System (Medtronic CV Luxembourg Sarl) prosthesis and the balloon-expandable Edwards SAPIEN™ transcatheter aortic heart valve prosthesis (Edwards Lifesciences, LLC, Irvine, California). Contemporary results are promising, with a considerable increase in aortic valve area and a decrease in the peak pressure gradient across the aortic valve. Most of all, there is substantial relief of symptoms such as dyspnea and angina.2 The current recommended treatment criteria for the two prosthetic systems do not include patients with degenerated bioprostheses or patients with aortic regurgitation (AR).2 This article presents the case of a valve-in-valve procedure in which a CoreValve prosthesis was inserted through the right subclavian artery into a 10-year-old degenerated aortic homograft with severe AR. Case Description The patient was an 86-year-old male who, in 1997, had undergone urgent cardiac surgery due to Type-A aortic dissection with implantation of a composite graft consisting of a 25 mm Björk Shiley mechanical aortic valve (Shiley, Inc., Irvine, California) and a 28 mm Vascutec vascular tube. In 1998, the mechanical aortic valve was infected with Staphylococcus epidermidis. Initially, the patient was treated with vancomycin and rifampicin, but after 3 weeks of treatment, he developed a severe allergic reaction with universal maculopapulous exanthema. Antibiotic treatment was put on hold for 1 week until the exanthema diminished, and was then re-established with erythromycin and rifampicin for 6 and 4 weeks, respectively. Due to positive blood cultures despite antibiotic treatment, it was decided to replace the mechanical valve with a 23 mm aortic homograft bioprosthesis with preservation of the vascular tube. Approximately 10 years later, the patient developed heart failure with dyspnea (New York Heart Association functional Class III), but no angina. On clinical examination, his blood pressure was 126/33 mmHg, and he presented with pulsus celer in addition to visible carotid and suprasternal pulsations. At stethoscopy over the aortic position, a systolic ejection murmur Grade II of IV, as well as a protodiastolic murmur II of IV, were heard. The electrocardiogram (ECG) revealed sinus rhythm with right bundle branch block. On chest X-ray, the aortic homograft and vascular tube were severely calcified, similar to a porcelain aorta. Transesophageal echocardiography showed severe AR (Figure 1) confirmed by aortography, but no AS was present. The left ventricle was moderately dilated with an inner end diastolic diameter of 64 mm and an ejection fraction of 50%. Furthermore, coronary angiography was performed, which demonstrated no significant stenoses. ECG-gated computer tomography (CT) with contrast of the great vessels and the aortic valve (Figure 2) were used to take measurements of the diameter of the aortic annulus of the aortic homograft, which was 24 mm. The patient was denied surgery based on his previous two valve replacements, advanced age, severely calcified aortic homograft and vascular tube, arterial hypertension and peripheral artery disease. Additionally, his logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 30%. After thorough multidisciplinary evaluation between cardiologists and thoracic surgeons, TAVI was offered to the patient, who consented and accepted the risks of this intervention. Procedure. The TAVI procedure was performed under general anesthesia and hemodynamic support in the form of a continuous infusion of low-dose noradrenalin. Neither a mechanical left ventricle support system nor extracorporeal bypass was used during the intervention. Vascular introduction of the CoreValve prosthesis is often performed percutaneously through one of the femoral arteries. Due to universal arteriosclerosis with severe stenoses and kinking of the ilio-femoral axis, femoral access could not be used in this patient. Consequently, the access for TAVI was created using surgical cutdown to the right subclavian artery and after end-to-side anastomizing of a 30 mm vascular Hemashield® tube (Boston Scientific Corp., Natick, Massachusetts ); an 18 Fr (6 mm) sheath was used to introduce the valve prosthesis. The right subclavian artery was chosen over the left due to anatomical conditions as well as calcification and plaque at the origin of the left subclavian artery from the aortic arch. Femoral access was used as well to measure pressure invasively. The valve used in this case was a third-generation, large-sized CoreValve nitinol porcine prosthesis, which in full expansion is 29 mm in diameter, corresponding to aortic annulus diameters between 24–27 mm3. After adjusting the position under fluoroscopy, the prosthesis was released from the introduction system. The delivery system was removed, and the subclavian artery access was surgically closed. The revalving time was 12 minutes and the total procedure time amounted to 245 minutes, primarily lengthened by the surgical vascular access. In comparison, percutaneous femoral access has an average duration of 120 minutes.3 The patient was extubated on the same day and was mobilized the following day. His daily antiplatelet regimen consisted of acetylsalicylic acid 75 mg indefinitely and clopidogrel 75 mg for 6 months. In this case, the insertion of the CoreValve prosthesis resulted in instantaneous hemodynamic improvement and a marked relief in symptoms. AR was decreased from severe regurgitation to a trivial paravalvular leak, and the dimensions of the left ventricle normalized during the first week following valve insertion. His left ventricular ejection fraction increased from 50% to 55%. ECG-gated CT of the aortic valve was preformed again post intervention (Figure 3), showing the CoreValve prosthesis correctly positioned inside the aortic homograft and vascular tube. The submission period amounted to 16 days, extended due to a right subclavian artery thrombosis, which was removed surgically and did not cause sequelae. Furthermore, due to third-degree atrioventricular block, the patient received a pacemaker 10 days after the valve insertion. Discussion The existing indication for applying TAVI is inoperable, severe AS, and the results are promising.2,3 Along with forthcoming results from long-term studies on the treatment of patients with inoperable AS and randomized studies comparing surgical aortic valve replacement (AVR) and TAVI, the indications for TAVI are expected to be expanded to include operable high-risk patients with AS and degenerated bioprostheses. When considering expansion of the indications for TAVI, it is key to distinguish between patients who are operable and those who are inoperable. If the patients are operable and have a well-documented, efficient alternative treatment option to TAVI, randomized studies must be established before making TAVI an equal choice of treatment. On the contrary, if the patients are inoperable and have a poor prognosis, TAVI has to be considered as an alternative to conservative treatment. This case of an inoperable patient presents three intriguing and challenging aspects. Firstly, the patient had a degenerated aortic bioprosthesis; secondly, the indication was AR; and thirdly, the vascular access was the right subclavian artery. Aortic Bioprostheses. The benefit of bioprostheses compared to mechanical valves is that anticoagulation treatment is not needed.4 Currently, the guidelines from the American Heart Association recommend bioprostheses in surgical AVR for patients > 65 years of age. Additional indications for the use of bioprostheses include: acute endocarditis, where a homograft is preferred, and contraindication for anticoagulation treatment.4 Nevertheless, the final choice of either a mechanical valve or a bioprosthesis is based on several considerations such as the age of patient, long-term complications from chronic anticoagulant therapy and the expected valve durability. Valve durability and long-term anticoagulant therapy are opposing aspects when deciding whether to use a mechanical valve or a bioprosthesis. In younger patients, the progression of valve deterioration in bioprostheses is increased compared to elderly patients. The 10-year valve deterioration rate is 60% in patients aged 16–39 years at the time of insertion of a bioprosthesis,5 making the choice of a mechanical valve more obvious in younger patients. On the contrary, the 10-year valve deterioration rate is 70 years of age at the time of AVR with a bioprosthesis.5 Furthermore, anticoagulant treatment of elderly patients presents a higher risk of bleeding than in younger patients,6 which makes bioprostheses the better choice in elderly patients. Nevertheless, structural valve deterioration5 in the elderly is a complication that must be considered, especially in light of the advancing age of the general population.7 Durability of aortic bioprostheses is, however, at times exceeded by the potential lifespan of an otherwise vigorous and healthy elderly patient. In some cases, a high estimated operational risk could compromise surgical AVR of degenerated bioprostheses due to advanced age and comorbidities. Therefore, there is a significant need of an effective alternative treatment option for inoperable patients with degenerated bioprostheses, which TAVI may offer. TAVI has been shown to be a promising method for first-time valve insertion due to AS.2,3 Moreover, the concept of this method applied to “valve-in-valve” procedures has been established in the mitral position,5 and has also shown strong possibilities in the pulmonary valve position.6 Until now, there has only been one reported case of TAVI-“valve-in-valve” within a bioprosthesis in the aortic position.7 Aortic Regurgitation. The onset of angina or significant dyspnea is usually an indication for surgical AVR, thus there are no contemporary large studies of the natural history of symptomatic patients with AR. Previous reports of the natural history of AR showed greatly varied 5-year mortality rates between 2% and 62%.11,12 Nevertheless, it has been established that conservatively managed AR has a 10-year mortality rate of 34%, and a 10-year heart failure morbidity rate of 47%.13 It can therefore be anticipated that inoperable patients with symptomatic severe AR due to degenerated bioprostheses are in need of an effective treatment option. AR in degenerated bioprostheses has thus far not been an indication for TAVI. A concern about applying TAVI in AR within native aortic valves has been that a lack of calcification would not leave an anchor for the valve prosthesis. However, this may not be a problem in bioprostheses due to the high frequency of calcification in bioprostheses.8 As shown in this case, the radial force of the CoreValve prosthesis was well accommodated within the calcified homograft. Subclavian Access. The CoreValve introduction system is 6 mm in diameter, which is consequently the minimally required diameter for vascular access.3 The most frequently used vascular access for introduction of the CoreValve prosthesis is percutaneously through one of the femoral arteries. Even patients with challenging aorto-iliofemoral access can often be treated through the femoral pathway.9 The subclavian arteries can otherwise be used, as in this case, where it was not possible to pass through the iliofemoral vasculature.10 However, this requires surgical cutdown, which lengthens the process. If there is no calibrated vascular access, TAVI can be performed via transapical access through a mini-thoracotomy.2 Perspectives This case exemplifies the potential application of TAVI on challenges other than purely inoperable AS such as degenerated bioprostheses. The indications criteria are still in the developing phase, and cases like the one presented here may push the limits and expand the treatment possibilities. The recommended greater usage of bioprostheses,8 along with the aging population, will require more valve implantations as well as replacements of valve prostheses, which combined with the frequent comorbidities in the elderly population, make TAVI an attractive treatment modality. The size of the cohort of inoperable patients with degenerated bioprostheses or AR, in addition to the high-risk operable patients with AS, has yet to be estimated. However, the perspectives of expanding the treatment indication are within reach and the cohort is expected to be very large. Acknowledgement. We wish to thank Dr.Thomas Kristensen, Department of Radiology, Rigshospitalet, Copenhagen, Denmark, for his assistance.

2. Vahanian A, Alfieri OR, Al-Attar N, et al. Transcatheter valve implantation for patients with aortic stenosis: A position statement from the European Association of Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur J Cardiothorac Surg 2008;34:1–8.

3. Piazza N, Grube E, Gerckens U, et al. Procedural and 30-day outcomes following transcatheter aortic valve implantation using the third generation (18 Fr) CoreValve ReValving System: Results from multicentre, expanded evaluation registry 1-year following CE mark approval. EuroInterv 2008;4:1–8.

4. American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Society of Cardiovascular Anesthesiologists; Society for Cardiovascular Angiography and Interventions; Society of Thoracic Surgeons, Bonow RO, Carabello BA, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients with Valvular Heart Disease): Developed in collaboration with the Society of Cardiovascular Anesthesiologists: Endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. Circulation 2006;114:84–231.

5. Kempfert J, Blumenstein JM, Borger MA, et al. Minimally invasive off-pump valve-in-a-valve implantation: The atrial transcatheter approach for re-operative mitral valve replacement. Eur Heart J 2008;29:2382–2387.

6. Nordmeyer J, Coats L, Lurz P, et al. Percutaneous pulmonary valve-in-valve implantation: A successful treatment concept for early device failure. Eur Heart J 2008;29:810.

7. Wenaweser P, Buellesfeld L, Gerckens U, Grube E. Percutaneous aortic valve replacement for severe AR in degenerated bioprosthesis: The first valve in valve procedure using the CoreValve ReValving System. Catheter Cardiovasc Interv 2007;70:760–764.

8. Schoen FJ, Levy RJ. Calcification of tissue heart valve substitutes: progress toward understanding and prevention. Ann Thorac Surg 2005;79:1072–1080.

9. Jilaihawi H, Spyt T, Chin D, et al. Percutaneous aortic valve replacement in patients with challenging aortoiliofemoral access. Catheter Cardiovasc Interv 2008;72:885–890.

10. Ruge H, Lange R, Bleiziffer S, et al. First successful aortic valve implantation with the CoreValve ReValving™ System via right subclavian artery access: A case report. Heart Surg Forum 2008;11:E323–E324.