Clinical research Low-gradient aortic stenosis: impact of prosthesis-patient mismatch on survival

Aims To assess the prognostic impact of prosthesis-patient mismatch (PPM) in a large consecutive series of patients operated for low-gradient aortic stenosis (AS). Methods and results Outcomes after surgery for low-gradient AS were prospectively assessed in 152 consecutive patients from seven institutions. There were 113 men (74%); mean age was 72 years (64–76); valve area, 0.7 cm2 (0.6–0.8); left ventricular (LV) ejection fraction 0.31 (0.25–0.37) and base-line mean transaortic pressure gradient (MPG), 30 mmHg (25–35) Among 139 patients with available prosthetic valve effective orifice area (EOA), PPM (defined by an indexed EOA 0.85 cm2/m2) was present in 79 patients (57%) and had no significant impact on post-operative mortality. Independent pre-dictors of overall mortality were LV contractile reserve [hazard ratio (HR) 0.52; 95 % confidence interval (CI) 0.35–0.78; P 0.002], associated coronary artery bypass grafting (HR 1.87; 95 % CI 1.24–2.82; P 0.003), baseline MPG (per 1 mmHg decrease to 10 mmHg; HR 1.03; 95 % CI 1.01–1.06; P 0.021), previous cancer (HR 2.13; 95 % CI 1.05–4.29; P 0.037), and logistic EuroSCORE (per 1 % increase; HR 1.02; 95 % CI 1.01–1.04; P 0.040). Conclusion In this large multicentre series of patients with low-gradient AS, we found that PPM (moderate in most cases) had no influence on post-operative mortality. Therefore, the performanc