Eight-year outcomes for patients with aortic valve stenosis at low surgical risk randomized to transcatheter vs. surgical aortic valve replacement

Selected in European Heart Journal by S. Brugaletta

Read more about the Nordic Aortic Valve Intervention (NOTION) trial to compare clinical outcomes and durability of bioprosthetic aortic valves 8 years after TAVI and SAVR.

Reviewer

Salvatore Brugaletta

@sbrugaletta

Interventional cardiologist / Cardiologist

Barcelona, Spain

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My Comment

Why this study? – the rationale/objective

Transcatheter aortic valve implantation (TAVI) has expanded rapidly for the treatment of symptomatic severe aortic valve stenosis (AS) after multiple randomized clinical trials have demonstrated TAVI to be either non-inferior or superior to surgical aortic valve replacement (SAVR) in short- and mid-term outcomes.

The limited data on long-term clinical outcome after TAVI compared to SAVR, as well as the durability of transcatheter heart valves (THV), have been raised as a concern for expansion of TAVI to patients with longer life expectancy.

Expanding on previous mid-term follow-up data from the NOTION trial, the aims of the present study were to report clinical outcomes and durability of bioprosthetic aortic valves 8 years after TAVI and SAVR.

How was it executed? – the methodology

The Nordic Aortic Valve Intervention (NOTION) trial randomized patients with symptomatic severe aortic stenosis at lower surgical risk to TAVI or SAVR between 2010 and 2013.

Clinical status, echocardiography, structural valve deterioration, and failure were assessed using standardized definitions. In total, 280 patients were randomized to TAVI (n = 145) or SAVR (n = 135). All-cause mortality, stroke or myocardial infarction, as well as structural valve deteriorations, were evaluated at 8-year follow-up.

What is the main result?

Baseline characteristics were similar, including mean age of 79.1 ± 4.8 years and a mean STS score of 3.0 ± 1.7 %.

At 8-year follow-up, the estimated risk of the composite outcome of all-cause mortality, stroke, or myocardial infarction was 54.5 % after TAVI and 54.8 % after SAVR (P = 0.94). The estimated risks for all-cause mortality (51.8 % vs. 52.6 %; P = 0.90), stroke (8.3 % vs. 9.1 %; P = 0.90), or myocardial infarction (6.2 % vs. 3.8 %; P = 0.33) were similar after TAVI and SAVR. The risk of structural valve deterioration was lower after TAVI than after SAVR (13.9 % vs. 28.3 %; P = 0.0017), whereas the risk of bioprosthetic valve failure was similar (8.7 % vs. 10.5 %; P = 0.61).

Critical reading and the relevance for clinical practice:

Use of TAVI in low-risk patients is limited by lack of evidence in the long-term follow-up about duration of TAVI prosthesis, as compared to surgical biological prosthesis.

The 8-year follow-up of the NOTION trial gives us some insights about this long-term durability, showing specifically persistence of a good valve function without any loss of function.

Some points should be highlighted:

1. This follow-up was not powered for any endpoint, so it should be considered as hypothesis-generating for a future powered study or for a meta-analysis.
2. Second, it is surprising to see a 30 % structural valve deterioration in the SAVR group: as suggested by the authors, it may be due to the high use of Mitroflow and Trifecta prostheses, which have been reported to have a higher risk of earlier deterioration.
3. Eventually, permanent pacemaker in the TAVI group and new-onset atrial fibrillation in the SAVR group should be considered when these procedures are offered to the patient.

Please share your view about the future use of TAVI in low-risk patient.