Comparison of Early Surgical or Transcatheter Aortic Valve Replacement Versus Conservative Management in Low-Flow, Low-Gradient Aortic Stenosis Using Inverse Probability of Treatment Weighting: Results From the TOPAS Prospective Observational Cohort Study.

Background No randomized comparison of early (ie, ≤3 months) aortic valve replacement (AVR) versus conservative management or of transcatheter AVR (TAVR) versus surgical AVR has been conducted in patients with low-flow, low-gradient (LFLG) aortic stenosis (AS). Methods and Results A total of 481 consecutive patients (75±10 years; 71% men) with LFLG AS (aortic valve area ≤0.6 cm/m and mean gradient <40 mm Hg), 72% with classic LFLG and 28% with paradoxical LFLG, were prospectively recruited in the multicenter TOPAS (True or Pseudo Severe Aortic Stenosis) study. True-severe AS or pseudo-severe AS was adjudicated by flow-independent criteria. During follow-up (median [IQR] 36 [11-60] months), 220 patients died. Using inverse probability of treatment weighting to address the bias of nonrandom treatment assignment, early AVR (n=272) was associated with a major overall survival benefit (hazard ratio [HR], 0.34 [95% CI, 0.24-0.50]; <0.001). This benefit was observed in patients with true-severe AS but also with pseudo-severe AS (HR, 0.38 [95% CI, 0.18-0.81]; =0.01), and in classic (HR, 0.33 [95% CI, 0.22-0.49]; <0.001) and paradoxical LFLG AS (HR, 0.42 [95% CI, 0.20-0.92]; =0.03). Compared with conservative management in the conventional multivariate model, trans femoral TAVR was associated with the best survival (HR, 0.23 [95% CI, 0.12-0.43]; <0.001), followed by surgical AVR (HR, 0.36 [95% CI, 0.23-0.56]; <0.001) and alternative-access TAVR (HR, 0.51 [95% CI, 0.31-0.82]; =0.007). In the inverse probability of treatment weighting model, trans femoral TAVR appeared to be superior to surgical AVR (HR [95% CI] 0.28 [0.11-0.72]; =0.008) with regard to survival. Conclusions In this large prospective observational study of LFLG AS, early AVR appeared to confer a major survival benefit in both classic and paradoxical LFLG AS. This benefit seems to extend to the subgroup with pseudo-severe AS. Our findings suggest that TAVR using femoral access might be the best strategy in these patients. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01835028.