Impact of sex-specific thresholds for low flow in assessment of prognosis in concordantly and discordantly graded aortic valve stenosis.

Objective: Sex-specific low flow was recently defined as stroke volume index (SVi) ≤40 ml/m² in men and ≤32 ml/m² in women. We tested the prognostic association of these cut-offs in patients with aortic stenosis (AS) with concordantly and discordantly graded AS (CGASEL and DGASEL) based on pressure recovery adjusted aortic valve area (energy loss, EL).

Methods: Data from 1351 patients with asymptomatic AS, peak jet velocity <4m/s and preserved left ventricular ejection fraction enrolled in the Simvastatin and Ezetimibe in AS study was used. DGASEL was defined as EL <1.0 cm² with mean aortic gradient <40 mmHg, and CGASEL as EL ≥1.0 cm² with mean aortic gradient <40mmHg. Patients were further grouped into normal and low flow. Outcome was combined all-cause death and hospitalization for heart failure.

Results: CGASEL with normal/low flow was present in 915/253 patients, and DGASEL with normal/low flow in 57/126 patients. During median 4.3 years follow-up, event-free survival was lower in patients with DGASEL irrespective of flow compared to CGASEL with normal flow (p<0.05). In Cox regression analysis, DGASEL with normal or low flow were both associated with increased risk of all-cause death and hospitalization for heart failure after adjustment for age, sex, heart rate, randomized study treatment, hypertension, aortic valve replacement and aortic valve calcification (p<0.05). No survival difference was found between patients with normal vs. low flow within groups of DGASEL or CGASEL.

Conclusions: Identification of low flow by the proposed sex-specific thresholds of SVi needs more prognostic validation before application in clinical practice.