True-severe stenosis in paradoxical low-flow low-gradient aortic stenosis: outcomes after transcatheter aortic valve replacement

Abstract

Aims: The ESC/EACTS guidelines propose criteria that determine the likelihood of true-severe aortic stenosis (AS). We aimed to investigate the impact of the guideline-based criteria of the likelihood of true-severe AS in patients with low-flow low-gradient (LFLG) AS with preserved ejection fraction (pEF) on outcomes following transcatheter aortic valve replacement (TAVR).

Methods and results: In a prospective TAVR registry, LFLG-AS patients with pEF were retrospectively categorized into high (criteria ≥6) and intermediate (criteria <6) likelihood of true-severe AS. Haemodynamic, functional, and clinical outcomes were compared with high-gradient AS patients with pEF. Among 632 eligible patients, 202 fulfilled diagnostic criteria for LFLG-AS. Significant haemodynamic improvement after TAVR was observed in LFLG-AS patients, irrespective of the likelihood. Although >70% of LFLG-AS patients had functional improvement, impaired functional status [New York Heart Association (NYHA III/IV)] persisted more frequently at 1 year in LFLG-AS than in high-gradient AS patients (7.8%), irrespective of the likelihood (high: 17.4%, P = 0.006; intermediate: 21.1%, P < 0.001). All-cause death at 1 year occurred in 6.6% of high-gradient AS patients, 10.9% of LFLG-AS patients with high likelihood [hazard ratio (HR)adj 1.43, 95% confidence interval (CI) 0.68-3.02], and in 7.2% of those with intermediate likelihood (HRadj 0.92, 95% CI 0.39-2.18). Among the criteria, only the absence of aortic valve area ≤0.8 cm2 emerged as an independent predictor of treatment futility, a combined endpoint of all-cause death or NYHA III/IV at 1 year (OR 2.70, 95% CI 1.14-6.25).

Conclusion: Patients with LFLG-AS with pEF had comparable survival but worse functional status at 1 year than high-gradient AS with pEF, irrespective of the likelihood of true-severe AS.

Clinical trial registration: https://www.clinicaltrials.gov. NCT01368250.

Keywords: Aortic stenosis; Low-flow low-gradient aortic stenosis; Preserved ejection fraction; Transcatheter aortic valve implantation; Transcatheter aortic valve replacement.