Propensity score-matched analysis of patients with severe aortic stenosis undergoing surgical aortic valve replacement

OBJECTIVE: Severe aortic stenosis (AS) is one of the most serious valve conditions. Patient demography and the aetiology of AS have substantially changed in the past several decades along with a drastic improvement of surgical aortic valve replacement (SAVR) and its associated procedures. Contemporary patients with severe AS have multiple comorbidities and live much longer. We aimed to elucidate the treatment effects of SAVR on long-term outcome in propensity score (PS)-matched and the entire patient populations. METHODS: We retrospectively reviewed 570 patients with severe AS defined as an aortic valve area of 1.0 cm(2) or less. Systemic differences in 39 baseline characteristics between non-SAVR and SAVR groups were adjusted using PS matching method. The endpoints included all-cause mortality and cardiovascular events that included heart failure, non-fatal stroke, syncope and acute coronary syndrome. RESULTS: Overall, 55% of the entire population (mean age 78 years; males 41%) were symptomatic. During 3.9 years of the median follow-up, 210 (36%) patients underwent SAVR and 231 (41%) died. Cumulative incidences of mortality and both mortality and cardiovascular events were significantly higher in the non-SAVR group than in the other group (p<0.001, each). Among 101 PS-matched pairs, SAVR correlated with a lower mortality risk (HR 0.35; 95% CI 0.21 to 0.59; p<0.001)) and mortality and cardiovascular events combined (HR 0.62; 95% CI 0.42 to 0.92; p=0.02). However, survival difference between both groups was markedly smaller among asymptomatic patients in the subgroup of matched patients. CONCLUSION: Patients with AS undergoing SAVR exhibit a lower incidence of all-cause mortality and major cardiovascular events than those not undergoing surgical interventions, even after the baseline characteristics are balanced by the PS matching. The correlation between SAVR and survival from cardiovascular events is less evident among asymptomatic patients.