What is the recommended maximum number of valve-in-valve Transcatheter Aortic Valve Replacement (TAVR) procedures in an aortic tissue valve originally implanted via open heart surgery?

Maximum Number of Valve-in-Valve TAVR Procedures in Aortic Tissue Valves

There is currently no established maximum number of valve-in-valve TAVR procedures that can be performed in an aortic tissue valve originally implanted via open heart surgery, but a single valve-in-valve TAVR is the standard approach with insufficient evidence supporting multiple sequential procedures.

Understanding Valve-in-Valve TAVR

Valve-in-valve (ViV) TAVR has emerged as an important treatment option for patients with failing bioprosthetic aortic valves. According to the 2012 ACCF/AATS/SCAI/STS expert consensus document, this approach is particularly valuable for patients at high risk for reoperative conventional AVR 1.

Key Considerations for ViV TAVR:

1. Anatomical Requirements:

   • The original bioprosthetic valve must be large enough to prevent patient-prosthetic mismatch with the TAVR valve 1
   • Coronary anatomy must be carefully defined to minimize the risk of coronary obstruction 1

2. Risk Assessment:

   • Initially recommended only for patients at high or prohibitive surgical risk
   • More recent guidelines have expanded indications to include intermediate-risk patients 1

Evidence on Multiple ViV TAVR Procedures

The current guidelines and literature do not specifically address the maximum number of sequential ViV TAVR procedures that can be performed. However, several important factors limit the feasibility of multiple procedures:

Limiting Factors:

1. Progressive Reduction in Effective Orifice Area:

   • Each subsequent valve implantation reduces the effective orifice area
   • This increases the risk of severe patient-prosthesis mismatch and poor hemodynamics

2. Coronary Access Concerns:

   • Multiple layers of valve stents can progressively obstruct coronary ostia
   • This creates both acute risk during the procedure and eliminates future coronary intervention options

3. Durability Considerations:

   • Limited long-term data exists even for a single ViV TAVR procedure
   • The PARTNER IA trial showed no structural valve deterioration requiring repeat AVR at 5 years 1
   • However, no robust data exists on durability beyond this timeframe or for multiple ViV procedures

Clinical Decision-Making Algorithm

For patients with a failing surgical bioprosthetic valve:

1. First Intervention for Valve Failure:

   • For high or prohibitive surgical risk: ViV TAVR is recommended 1
   • For low surgical risk: Surgical re-replacement remains the standard of care

2. Second Valve Failure (after ViV TAVR):

   • Comprehensive evaluation of:
     • Residual valve area (must be sufficient to accommodate another valve)
     • Coronary height (to avoid obstruction)
     • Patient's overall risk profile
   • Consider surgical explantation of all prostheses if feasible
   • A second ViV TAVR may be considered in highly selected cases where surgery is contraindicated

3. Beyond Second Valve Failure:

   • Surgical intervention should be strongly considered if at all possible
   • Multiple (>2) ViV TAVR procedures have not been well-studied and carry theoretical risks of:
     • Severe hemodynamic compromise
     • Coronary obstruction
     • Uncertain durability
     • Technical challenges with deployment

Important Caveats

1. Size of Original Surgical Valve:

   • Larger surgical valves (≥23mm) allow for better hemodynamics after ViV TAVR
   • Small surgical valves may not be suitable even for a single ViV TAVR due to risk of severe patient-prosthesis mismatch

2. Patient Life Expectancy:

   • For younger patients, surgical re-replacement may be preferred to preserve future options
   • For elderly patients with limited life expectancy, a single ViV TAVR may be sufficient

3. Valve Design Considerations:

   • Supra-annular valve designs may provide better hemodynamics for ViV procedures
   • Newer TAVR valve iterations may eventually allow for more favorable outcomes in multiple ViV scenarios

Conclusion

While valve-in-valve TAVR is an established procedure for failing bioprosthetic valves in high-risk patients, there is insufficient evidence to support multiple sequential ViV TAVR procedures. A single ViV TAVR should be considered the standard approach, with careful evaluation of anatomical and hemodynamic factors before contemplating any additional transcatheter interventions.