Clinical Update Thirty: Prosthesis Choice

Criteria for modification of prosthesis choice

Do transapical and percutaneous aortic valve technologies represent the ideal prostheses? Will they ever?

Patients Not Treated Symptomatic AV Stenosis

Risks of increased surgical mortality and morbidity rates in elderly aortic valve replacement patients and the need to effectively treat these patients has led to new product development of less invasive treatment options. Among the leading treatment modalities being clinically tested for this population are Percutaneous Aortic Valve Replacement (PAVR) and Trans-Apical Aortic Valve Replacement (TAVR). Recent published articles estimate that 30% to 60% of symptomatic patients are not treated due to the risks associated from surgery in this group.

Mortality among untreated symptomatic patients with severe AS is extremely high adding importance to the need to identify alternative treatments such as PAVR and TAVR.

Understanding the need for treatment of these patients and in anticipation of use of PAVR and TAVR the Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgeons (AATS) and the Society for Cardiovascular Angiography and Interventions (SCAI) produced a position statement regarding the clinical development of percutaneous heart valve technology which has the following summary:

“Although percutaneous devices for repair or replacement of heart valves appear promising, they are clearly in an early stage of development. Many critical questions remain unanswered, including the durability of these devices and the potential adverse effects they may have on subsequent valve surgery. Therefore, one cannot justify the use of these experimental technologies in patients for whom published guideline indications do not exist or in situation of prophylactic therapy until data on safety and effectiveness are gathered from well-designed clinical trials. Study candidates should consist of symptomatic patients in whom long-term survival is already severely compromised. Such a strategy would allow the collection of mid-term device durability data while providing much needed clinically relevant safety and effectiveness data.

Prospective, randomized, clinical trials provide the most reliable evidence of the effectiveness of the treatment.
Without such trial, ineffective treatments (or worse, harmful treatments) may be accepted in medical practice. Our collective enthusiasm for new, less-invasive cardiovascular approaches should not divert us from the importance of evaluation these devices in the context of a controlled clinical trial environment. Success of these clinical trials ultimately depends upon a sincere commitment to collaboration between cardiology and cardiac surgery.”6

The need to maintain clinical trial focus on the patients for which the technology was developed has been emphasized by several well established cardiac surgeons and their research teams:

“In summary, we believe that based on age alone, with minimal comorbitdities (sp.), conventional primary, isolated AVR [aortic valve replacement] remains the standard of care and can be performed with low morbidity and in- hospital mortality and acceptable long-term survival. It is plausible that in patients with advanced age and additional comorbitdities, percutaneous (transfemoral or transapical) AVR may provide potential benefits in postoperative morbidity and mortality.”

Partner US Pivotal Trial Inclusion/Exclusion Criteria

Galloway, et al.8
“The development of PAVRs may offer promising treatment options for patients with severe aortic stenosis who are deemed inoperable owing to comorbid conditions. Cumulative data obtained from recent trials show that current PAVR technology has a successful implantation rate of only 80% and a mortality rate of 19% in patients after successful implantation…. Most important, PAVR must therefore be compared with conventional open-heart AVR. The data presented indicate that the EuroSCORE grossly overestimates the surgical mortality of high-risk patients undergoing isolated AVR. It is therefore not an accurate standard to select for “high-risk patients” or to determine the survival benefit of PAVR compared with conventional surgery.”

“Based upon logic and presently already available data, longterm results will be significantly inferior to conventional aortic valve replacement.”

Which patients are being considered for TAVR and PAVR trials?

The Sapien aortic valve is produced in both TAVR and PAVR configurations. The Sapien valve received CE approval in 2007 and is available for purchase in Europe. In the US, the PARTNER trial will determine Sapien valve approval by the FDA. The patient inclusion/exclusion criteria for the PARTNER trial are listed below. It is obvious that the patient population for which the TAVR and PAVR is being considered are “high risk, symptomatic patients with aortic stenosis.”

The competing transcatheter technology to Sapien is CoreValve. CoreValve has also received CE approval, but the path to FDA approval is undetermined.

Baseline and Results for Sapien11-13


  • Mean age 81.7 years
  • Mean Gradient 53.2 mm Hg
  • NYHA Class I:1.4%, Class II: 19.6%, Class III: 62.2%, Class IV 16.8% Results
  • Implant success; 96%
  • 30 day survival 92%
  • Valve gradient, valve area and NYHA functional class were improved at 6 months
  • Overall survival at six months was 90%

What are the disadvantages?

  • Permanent pacemaking requirement 8.5% to 18%
  • Vascular complications 6-7%
  • Other complications 2% (tamponade, valve embolization)
  • Post-op mitral valve incompetence
  • Bicuspid contraindication
  • Cost of PAVR or TAVR are approximately $20,000 greater than a standard valve
  • Cost associated with additional clinical personnel have not been quantified

Summary of Results to Date

“Both studies used the Sapien transcatheter aortic valve. In the first study, called SOURCE, European researchers followed 303 patients who received the valve via transfemoral implantation. The 30-day survival rate was 94% in a high-risk population with multiple co-morbidities. These patients have a predicted mortality > 10% with conventional surgery.

In the second study, called PARTNER EU, the transfemoral arm had a 30-day survival rate of 96.3% and a six-month survival rate of 90%. At six months, patients continued to show improvement in valve gradient, valve area and NYHA functional class. Mean EUROSCORE (European System for Cardiac Operative Risk Evaluation) was 25.3%. Patients in the transapical arm, which involves a small thoracotomy incision, were higher risk, with a mean EUROSCORE of 33.5%; these patients had a six-month survivla rate of just 55%.

While the valve is currently on the market in Europe, it is still being studied in the United States in the PARTNER trial. The valve is expected to be approved in the U.S. by 2011. While valve replacement surgery is currently the standard, the new data suggest that percutaneous valve replacement is a viable *AMI = acute myocardial infarction treatment option for high-risk patients.”

Freedom from Explantation for Structural Valve Deterioration

Points to consider for TAVR/PAVR

  • All transcatheter valves are made of animal tissue.
  • The best possible durability will be similar to existing stented tissue valves – structural deteriation begins at 5-7 years and is approximately 50% within 15 years for patients less than 65 years old.14. (Figure 2)
  • The actual durability for these valves has not been determined.
  • When failures occur, especially in small sizes, a strategy for replacement must be developed.


It presently appears that PAVR and TAVR technologies may prove to be acceptable valve choice options for the very elderly patient who are otherwise poor surgical risks and have high mortality if untreated.

The effectiveness, suitability and cost rationale of these new treatments in younger, healthier patients remain undetermined until clinical studies for this group have been instituted and completed.



  1. Mohr F. Aortic valve disease 2020, a surgeon’s view. Presented at Dallas-Leipzig International Valve Congress. Dallas, Texas USA, April 23-25, 2009
  2. Charlson E, Legedza ATR, Hamel MB. Decision-making and outcomes in sever symptomatic aortic stenosis. J Heart Valve Dis 2006;15:312-21
  3. Pellikka PA, Sarano ME, Nishimura RA, et al. Outcome of 622 adults with asymptomatic, hemodynamically significant aortic stenosis during prolonged follow-up. Circulation 2005; 111: 3290-95
  4. Iung B, Baron G, Butchart EG, et al. A prospective survey of patients with valvular heart disease in Europe: The Euro Heart Survey on Valvular Heart Disease. European Heart J 2003;24:1231-43
  5. Bouma BJ, van den Brink RBA, van der Meulen JHP, et al. To operate or not on elderly patients with aortic stenosis: the decision and its consequences. Heart 1999;82:143-48
  6. American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA), Thomas A. Vassiliades, Jr, Peter C. Block, Lawrence H. Cohn, David H. Adams, Jeffrey S. Borer, Ted Feldman, David R. Holmes, Warren K. Laskey, Bruce W. Lytle, Michael J. Mack, and David O. Williams The clinical development of percutaneous heart valve technology: A position statement of the Society of Thoracic Surgeons (STS), the American Association for Thoracic Surgery (AATS), and the Society for Cardiovascular Angiography and Interventions (SCAI). J Thorac Cardiovasc Surg 2005; 129:970-76
  7. Thourani VH, Myung R, Kilgo P, et al. Long-term outcomes after isolated aortic valve replacement in octogenarians: A modern perspective. Ann Thorac Surg 2008;86:1458-65
  8. Grossi EA, Schwartz CF, Yu PJ, et al. High-risk aortic valve replacement: Are the outcomes as bad as predicted? Ann Thorac Surg 2008; 85:102-07
  9. Robicsek F (editorial). Will the use of percutaneous aortic valves remain compassionate? Eur J Cardiothorac Surg 2008;34:9-10
  10. Partner Trial: Placement of aortic transcatheter valve trial. Sponsored by Edwards Lifesciences.
  11. Cohn LH. In 10 years all aortic stenosis will be treated with a catheter. Presented at Dallas-Leipzig International Valve Congress. Dallas, Texas USA, April 23-25, 2009
  12. Makkar RR, Fontana G. Why is Edwards-Sapient THV a better valve? Presented at Dallas-Leipzig International Valve Congress. Dallas, Texas USA, April 23-25, 2009
  13. Kalia S. Percutaneous heart valves, is it time yet? SMH Capital, Houston, Texas 2009;49
  14. Smedira NG, Blackstone EH, Roselli EE, et al. Are allografts the biologic valve of choice for aortic valve replacement in nonelderly patients? Comparison of explantation for structural valve deterioration of allograft and pericardial prostheses. J Thorac Cardiovasc Surg 2006;131:558-64


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