Effect of patient prosthesis mismatch on clinical outcomes following surgical aortic valve replacement

Abstract Introduction Patient prosthesis mismatch (PPM) after surgical aortic valve replacement (SAVR) occurs when the valve’s effective orifice area (EOA) does not allow appropriate cardiac output to meet demand, causing increased transvalvular gradients. The literature is conflicting regarding the effect of PPM on long-term mortality and other adverse outcomes. Purpose To characterise the effect of PPM on all-cause mortality, cardiovascular death, heart failure hospitalisation and major adverse cardiac events (MACE; a composite of cardiovascular death, myocardial infarction, and stroke) following SAVR, stratified by sex. Methods This retrospective cohort study uses data from the Western Australia Heart Valves Study linked to administrative health data and includes all patients who underwent SAVR in Western Australian public hospitals between 2010-2020. PPM was defined according to the Valve Academic Research Consortium 3 criteria. The indexed EOA was derived from body surface area and published in-vivo EOA’s calculated for each prosthesis model and size. Results During the study period 1837 patients underwent SAVR (mean age 65 ± SD 14 years, 31% female). Median follow-up was 3.76 years (IQR 1.73-6.62). A mechanical prosthesis was implanted in 579 (32%) patients. Moderate or severe PPM was present in 250 (14%) patients, whilst no significant PPM was present in 1587 (86%) patients. Compared to those without significant PPM, patients with PPM were older (69 ± 14 vs 64 ± 11 years; p<0.001); included more women (101/250; 40% vs 459/1587; 29%; p<0.001) and were more likely to have bioprosthetic SAVR (213/250; 85% vs 1045/1587; 66%; p<0.001). The presence of PPM (moderate or severe vs no significant PPM) was associated with increased all-cause death (Hazard Ratio (HR) 1.74, 95% CI 1.09-2.75), cardiovascular death (HR 2.44, 95% CI 1.33-4.48) and MACE (HR 1.89, 95 CI 1.17-3.04) in females in adjusted analyses, but not males (table). The presence of PPM was not associated with heart failure hospitalisation, overall or in either sex. Conclusion The presence of moderate or severe PPM is associated with increased all-cause death, cardiovascular death, and MACE in females only. These results highlight the importance of patient selection, valve choice and operative technique to minimise PPM, particularly in female patients.Table 1