Durability of transcatheter and surgical bioprosthetic aortic valves in patients at lower surgical risk

Selected in JACC by E.W. Holy , S. Brugaletta

The NOTION trial is among the first to provide comparative data regarding bioprosthetic valve durability for TAVR and SAVR from a randomised clinical trial in patients with low surgical risk for mortality.

Reviewers

Erik Walter Holy

Interventional cardiologist / Cardiologist

Andreas Grüntzig Catheterization Laboratories, University Heart Center Zurich -

Salvatore Brugaletta

@sbrugaletta

Interventional cardiologist / Cardiologist

Barcelona, Spain

Our Comment

This joint review is part of the PCRonline GLOBAL Journal Club Initiative by selected members of the EAPCI/PCR Journal Club and PCR NextGen, and is based on the underlying idea of “Bringing peers together, exchanging ideas, towards a common standard of care”.

Why this study – the rationale/objective?

Long-term data about durability of TAVR prosthesis, especially in comparison with surgical bioprostheses are lacking. The present study compares the durability of transcatheter and surgical bioprosthetic aortic valves at 6 years follow-up.

How was it executed – the methodology?

In the NOTION (Nordic Aortic Valve Intervention) trial all-comer patients with severe aortic stenosis and lower surgical risk for mortality (mean STS Score 3.0 for both groups) were randomised to TAVR using the self-expanding CoreValve (Medtronic) bioprosthesis (n=139) or SAVR using any commercially available surgical bioprosthetic aortic valve (n=135).

Durability of transcatheter and surgical bioprosthetic aortic valves was assessed at 6-year follow-up, according to standardised definitions. Moderate/severe structural valve deterioration (SVD) was defined as a mean gradient ≥20 mm Hg, an increase in mean gradient ≥10 mm Hg from 3 months post-procedure, or more than mild intraprosthetic aortic regurgitation (AR) either new or worsening from 3 months post-procedure.
Nonstructural valve deterioration (NSVD) was defined as moderate/severe patient-prosthesis mismatch at 3 months or moderate/severe paravalvular leakage. Bioprosthetic valve failure (BVF) was defined as: valve-related death, aortic valve reintervention, or severe hemodynamic SVD.

What is the main result?

• At 6 years, the rates of all-cause mortality were similar for TAVR (42.5%) and SAVR (37.7%) patients (p = 0.58). 
• The rate of SVD was higher for SAVR than TAVR (24.0% vs. 4.8%; p < 0.001), whereas there were no differences in NSVD (57.8% vs. 54.0%; p = 0.52) or endocarditis (5.9% vs. 5.8%; p = 0.95). 
• BVF rates were similar after SAVR and TAVR through 6 years (6.7% vs. 7.5%; p = 0.89).

Critical reading and the relevance for clinical practice

In line with previously published studies, the current analysis confirms overall a long-term favourable hemodynamic performance of the self-expanding CoreValve™ with low rates of BVF and its overall non-inferiority compared to surgical aortic valves.

The NOTION trial is among the first to provide comparative data regarding bioprosthetic valve durability for TAVR and SAVR from a randomised clinical trial in patients with low surgical risk for mortality. At 6-year follow-up the study demonstrated that in low-risk patients with severe symptomatic aortic stenosis the rate of structural valve deterioration of bioprosthetic valves according to current definitions is greater after SAVR than TAVR, while the rates of bioprosthetic valve failure, endocarditis, thrombosis and all-cause mortality were low and similar. 

Despite these encouraging results several limitations need to be considered:

• as for all currently available studies on durability of transcatheter heart valves it is important to emphasize on the paucity of data available due to low numbers of patients with an available follow-up beyond 5 years. While follow-up was available at 5 years with 100% compliance in all survivors, data was provided for barely 50% of the participants at 6 years;
• lack of adjudication of echocardiography data by a core laboratory;
• transcatheter heart valve durability is reported only in one type of transcatheter aortic prosthesis in this particular study. Hence, favourable results may not apply to other valve types.
• TAVR was associated with significantly higher rates of moderate para-valvular leaks.