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

Abstract

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 cm2/m2 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]; P<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]; P=0.01), and in classic (HR, 0.33 [95% CI, 0.22–0.49]; P<0.001) and paradoxical LFLG AS (HR, 0.42 [95% CI, 0.20–0.92]; P=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]; P<0.001), followed by surgical AVR (HR, 0.36 [95% CI, 0.23–0.56]; P<0.001) and alternative‐access TAVR (HR, 0.51 [95% CI, 0.31–0.82]; P=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]; P=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.

Keywords

• aortic stenosis
• low flow
• low gradient
• surgical aortic valve replacement
• survival
• transcatheter aortic valve replacement