With ongoing follow-up from comparative TAVI vs. SAVR clinical trials in low-risk patients, the release of new evidence and its impact on future clinical guidelines. Occasionally, studies like the one presented here help challenge pre-existing, potentially biased trends. This sub-analysis from the Polish AVALON registry, conducted across three major national centers, contradicts the well-established body of evidence favoring TAVI’s non-inferiority, or even superiority in secondary outcomes, often elevated by aggregation into composite outcomes widely observed in comparative analyses of both techniques for treating severe aortic stenosis.

The evidence comparing TAVI and SAVR in low-surgical-risk patients largely derives from PARTNER 3 with the Edwards Sapien 3® prosthesis (showing a benefit for TAVI at 1-2 years in the composite endpoint of death + stroke + rehospitalization, with the latter primarily influencing the outcome) and the Evolut-Low Risk study with the Medtronic CoreValve® prosthesis (demonstrating TAVI’s non-inferiority in the composite endpoint of mortality + disabling stroke). These studies supported the FDA and CE approvals of the respective prostheses. Extended follow-up in this cohort is available from the 5-year NOTION study.

The AVALON analysis initially included 2393 patients treated between 2015 and 2019, thereby avoiding older TAVI devices. Primary prostheses used were Edwards Sapien 3®, Medtronic CoreValve Evolut®, Boston Symetis®, and Abbott Portico® for TAVI, while SAVR patients received bioprostheses with proven durability (unlike PARTNER 3 and Evolut-Low Risk, where these aspects were not specified, or NOTION, where high usage of Mitroflow/Crown® or St. Jude Trifecta® was reported, known for early structural degeneration). In total, 629 patients received TAVI exclusively via transfemoral access, and 1764 underwent SAVR, predominantly through median sternotomy, with 4% receiving minimally invasive approaches. Although both groups were broadly comparable (all low-risk patients), a propensity-matching analysis was conducted on 13 clinical variables, including age, insulin-dependent or non-insulin-dependent diabetes, renal dysfunction grades, LVEF, and NYHA, with low tolerance for intergroup differences. Patients requiring interventions beyond aortic valve replacement were excluded, controlling for the higher rate of associated procedures commonly penalizing SAVR in randomized studies. Ultimately, 329 TAVI and 593 SAVR patients comprised the final analytical set.

With comparable low-risk patient groups, procedural mortality and survival up to 2 years were similar. However, SAVR demonstrated 30% lower mortality at 6 years (p = 0.13). Subgroup analysis revealed that men, those under 75 years, smokers, those with an EuroSCORE II <2, hypertensives, patients with AF, and those with CKD, benefited more from SAVR in terms of survival.

These results may partially be attributable to post-procedural morbidity. Nevertheless, the rate of pacemaker implantation during post-procedural hospitalization was low (SAVR 1.4% vs. TAVI 3.3%; p = 0.002), as were bleeding complications (SAVR 5.2% vs. TAVI 2.7%; p = 0.08), renal failure (SAVR 4.7% vs. TAVI 2.4%; p = 0.9), and stroke (SAVR 1.9% vs. TAVI 0.3%; p = 0.1). The study did not assess echocardiographic parameters such as paravalvular leakage or residual gradients, nor the incidence of new LBBB, which could explain the survival impact during follow-up. Additionally, factors such as porcelain aorta, prior thoracic radiation, aortic valve calcification patterns, and femoral access restrictions were not considered, potentially introducing selection bias inherent to retrospective studies.

The authors conclude that, while there is no demonstrated survival difference between TAVI and SAVR in the first two post-procedural years, beyond this period, SAVR is associated with improved survival. Extended follow-up of randomized studies in low-surgical-risk patients is needed to confirm these findings and draw definitive conclusions.

COMMENTARY:

This study, published in a prestigious journal, is grounded in real-world outcomes, as captured in a registry setting, and though retrospective, benefits from a careful design focused on producing accurate and conclusive results as opposed to potentially biased studies (e.g., isolated all-cause mortality analysis, 6-year follow-up, exclusion of procedures beyond aortic valve intervention, selection of proven prostheses, and manageable rates of perioperative complications, reflecting the expertise of operators and care teams). It shows better mid-term survival for SAVR compared to TAVI, aligning with meta-analyses like that of Barili et al., which indicated that TAVI offers survival benefits only within the first few months, with outcomes equalizing at two years and SAVR outperforming TAVI beyond this period, particularly in low-surgical-risk patients.

The registry’s findings again highlight the limitations of randomized evidence in establishing reliable recommendations and guiding clinical practice. Although clinical trials continue to shape treatment standards, they are subject to a rigorous selection process that limits real-world applicability. For instance, 80% of candidates in the NOTION study were excluded, and >40% in the AVALON registry had dual aortic lesions—the most common presentation of aortic valve disease—compared to only 4% in NOTION. It is known that dual-lesion patients face worse outcomes due to more extensive myocardial remodeling resulting from both pressure overload from stenosis and some degree of volume overload from insufficiency, unlike pure stenosis cases. Consequently, real-world data, though prone to selection bias, can be a valuable resource for illuminating patient outcomes with severe aortic stenosis and aiding in better treatment allocation.

REFERENCE:

Kowalówka AR, Kowalewski M, Wańha W, Kołodziejczak M, Mariani S, Li T, et al. Surgical and transcatheter aortic valve replacement for severe aortic stenosis in low-risk elective patients: Analysis of the Aortic Valve Replacement in Elective Patients From the Aortic Valve Multicenter Registry. J Thorac Cardiovasc Surg. 2022 Oct 28(22)01148-5. doi: 10.1016/j.jtcvs.2022.10.026.

Barili F, Freemantle N, Musumeci F, Martin B, Anselmi A, Rinaldi M, et al.; Latin European Alliance of CardioVascular Surgical Societies (LEACSS) and with the endorsement of the Latin American Association of Cardiac and Endovascular Surgery (LACES), LEACSS members are the Italian Society of Cardiac Surgery (FB FM MR MdM AP), the Portuguese Society of Cardiac Surgery (MSU), the French Society of Cardiac Surgery (JFV, AA) and the Spanish Society of Cardiac Surgery (JRR) Institutions. Five-year outcomes in trials comparing transcatheter aortic valve implantation versus surgical aortic valve replacement: a pooled meta-analysis of reconstructed time-to-event data. Eur J Cardiothorac Surg. 2022 May 2;61(5):977-987. doi: 10.1093/ejcts/ezab516.