Clinical presentation and outcomes after transcatheter aortic valve implantation in patients with low flow/low gradient severe aortic stenosis

Objectives To identify predictors of mortality, functional status, and hemodynamical changes of patients undergoing transcatheter aortic valve implantation (TAVI) for low flow/low gradient aortic stenosis (LF/LG AS). Background There is little published data regarding the outcomes of patients with LF/LG AS following TAVI. Methods Sixty-eight patients with severe AS, left ventricular dysfunction (ejection fraction [EF] <35%) and low flow (LF) AS underwent TAVI. Patients were stratified according to the aortic mean pressure gradient (low gradient [LG]; with P_mean ≤40 mm Hg and high gradient [HG]: P_mean >40 mm Hg). The baseline parameters and clinical outcomes were subsequently compared among the two groups. Cox proportional hazards were used to identify predictors of 6-month mortality. Results There were 38 patients in the LG group and 30 patients in the HG group. There were no significant difference in 30-day mortality between the two groups. The 6-month and 1-year mortality, however, was 3.8-fold and 2.8-fold higher in the LG group than in the HG group (37.8% vs. 10.3%, P=0.01 and 37.8% vs. 13.3%, respectively, P=0.01). Univariable predictors for 6-month mortality were: STS Score, aortic valve area, and aortic mean pressure gradient. However, only STS Score (HR 1.08, 1.04-1.12, P<0.001) remained as independent predictor in the multivariable analysis. Six months after TAVI, hemodynamical (EF>50%) and clinical (NYHA class I) improvements were shown in both HG and LG groups. Conclusions LF/LG AS does not influence procedural mortality after TAVI but exhibits a strong impact on 6-month and 1-year mortality. The survivors, however, exhibit considerable hemodynamical and clinical improvements. Therefore, risk stratification and TAVI benefit should be weighted in every patient with LF/LG AS.