Abstract 3711: Impact of Valve Prosthesis-Patient Mismatch on Short-Term Mortality After Aortic Valve Replacement with a Stentless Bioprosthesis
Background and objective: Several studies have reported that PPM is associated with worse hemodynamics, more cardiac events, and lower survival after aortic valve replacement (AVR). However, these studies included predominantly stented bioprostheses and mechanical valves. Because stentless bioprostheses have superior hemodynamic performance, they are generally associated with a lower prevalence of PPM (20–30%) compared to stented bioprosthesis (30–70%). However, there has been no study regarding the impact of PPM on postoperative outcomes in the subset of patients receiving a stentless bioprosthesis.
Methods and results The indexed valve effective orifice area (EOA) was estimated for each size of prosthesis being implanted in 409 consecutive patients who underwent AVR with a Medtronic Freestyle bioprosthesis. PPM was defined as not clinically significant if the projected indexed EOA was >0.85 cm2/m2, as moderate if it was >0.65 cm2/m2 and ≤0.85 cm2/m2 and as severe if was ≤0.65 cm2/m2. Thirty-day mortality was 6.4 % (26/409) for the whole cohort. Moderate PPM was present in 19 % (76/409) of patients and only 2 patients had severe PPM. Thirty-day mortality was significantly (P,0.001) higher (19.2%) in patients with moderate or severe PPM than in those with not clinically significant PPM (3.2%). On multivariate analysis the strongest independent predictors for operative mortality were female gender (P<0.0003), previous cardiac surgery (P<0.004), history of stroke (P<0.03), valve implantation as root replacement (P<0.001), and moderate or severe PPM (P<0.0001).
Conclusion: Although the prevalence of PPM is lower in this series of patients with a stentless bioprosthesis compared to what is generally reported in patients with a stented bioprosthesis, PPM remains a frequent and powerful risk factor for short-term mortality after AVR with a stentless bioprosthesis. Hence, the projected indexed EOA should be systematically calculated in these patients at the time of operation to estimate the risk of PPM and if anticipating PPM, alternative options should be considered in light of patient’s overall clinical conditions and risk-benefit ratio.