Impact of aortic stenosis severity and its interaction with prosthesis-patient mismatch on operative mortality...

The optimal timing of aortic valve replacement (AVR) in patients with severe aortic stenosis (AS) is a source of debate. Moreover, it has been shown previously that prosthesis-patient mismatch (PPM) is an independent predictor of operative mortality after AVR. The study aim was to assess the effect of the preoperative severity of AS and its interaction with PPM with respect to operative mortality after AVR.

The data were analyzed from 2,104 consecutive patients who had undergone AVR for severe AS. The patients were allocated to tertiles according to their preoperative indexed aortic valve area (AVAi) as: < 0.35 cm2/m2, 0.35 to 0.43 cm2/m2, and > 0.43 cm2/m2. PPM was defined as a projected postoperative indexed effective orifice area (EOAi) of the implanted prosthesis < 0.85 cm2/m2.

The operative mortality was 5.7% (n = 120). On multivariate analysis, an independent association was identified between the preoperative severity of AS and operative mortality (odds ratio [OR] = 2.00, p = 0.03 for AVAi < 0.35 cm2/m2; OR = 1.39, p = 0.32 for AVAi 0.35-0.43 cm2/m2). Notably, the impact of PPM was more important in patients with more severe AS (p = 0.046 for AVAi x EOAi interaction).

The study results confirmed that very severe AS (AVAi < 0.35 cm2/m2) is independently associated with operative mortality after AVR. The results also emphasized the importance of avoiding PPM in these patients.