Results of the OBSERVANT study: clinical characteristics and short-term outcome of the enrolled population treated with transcatheter versus surgical aortic valve implantation

Abstract

OBSERVANT represents the first national observational study on the comparative effectiveness of transcatheter aortic valve implantation (TAVI) vs surgical aortic valve replacement (SAVR) at short, medium and long term, in a patient population with severe aortic stenosis (AS). The aim of this paper is to describe patient characteristics and short-term outcomes of the enrolled population. OBSERVANT is an observational prospective multicenter cohort study that enrolled AS patients undergoing SAVR or TAVI from December 2010 to June 2012 in the participating hospitals. Information on demographic characteristics, health status prior to intervention, therapeutic approach, intraprocedural and 30-day outcomes was collected. An administrative follow-up was set up to collect data on long-term outcomes. The enrolled population included 7618 patients undergoing transfemoral/transubclavian TAVI (TF/TS-TAVI, n=1652), transapical TAVI (TA-TAVI, n=259) or SAVR (n=5707). SAVR patients were younger and with a lower risk profile than TAVI patients (logistic EuroSCORE: SAVR 6.4 ± 7.3%, TF/TS-TAVI 14.1 ± 12.1%, TA-TAVI 15.5 ± 11.0%; p<0.001). When 30-day mortality rates were stratified by logistic EuroSCORE, a statistically significant difference was found only in the patient subgroup with logistic EuroSCORE ≤5% (SAVR 1.0%, TF/TS-TAVI 4.7%, TA-TAVI 0.0%; p=0.005). Findings from the OBSERVANT study confirm that patients undergoing TAVI are older and sicker than patients undergoing SAVR. Nevertheless, the logistic EuroSCORE shows that, in Italy, also patients at intermediate surgical risk are treated with TAVI. Stratifying by logistic EuroSCORE, SAVR seems to be superior to TAVI in the subgroup of patients at very low risk. More sophisticated analyses on patient subgroups with comparable risk profile and on long-term follow-up will allow to obtain valuable information on the effectiveness of TAVI and SAVR procedures.