Is patient-prosthesis mismatch a predictor of survival or a surrogate marker of co-morbidities in cardiac surgery?

Patient-prosthesis mismatch (PPM) has ignited much debate and no definite conclusions have been drawn on the outcome of these patients. Therefore, additional large studies with long-term follow-up are required to help the cardiologist and surgeon outline the best therapeutic strategy for patients with high risk for PPM.Patients who underwent aortic valve replacement (AVR) from 2000 to 2013 were identified. Baseline and operative data was extracted and indexed effective orifice area calculated for each patient. The presence of PPM was defined in those patients with an iEOA ≤0.85cm(2)/m(2). Regression analyses were performed to determine the association of PPM with operative mortality, post-operative complications and survival. Predictors for PPM were evaluated based on clinical and operative data.From 2023 patients who underwent AVR, PPM was present in 64.6%. These patients had increased age, more coronary artery bypass procedures, increased risk of diabetes, hypertension, higher creatinine values and higher Euroscore. Age, body surface area, prosthesis type and size were found to be predictors of mismatch. Operative mortality (8.1% vs 5.7%, p=0.05), stroke (3.9% vs 2.4, p=0.02) and acute kidney injury (47.6% vs 35.1%, p=<0.001) were more frequent in patients with PPM and mean 10-year survival was reduced (6.6years, 95% CI: 6.3-6.8 vs 7.3, 95% CI: 6.9-7.2, p<0.001). After adjusting for confounders, PPM was not found to be associated to either adverse outcome or survival.Patients with PPM have worse operative mortality, post-operative complications and survival mainly due to the fact that they represent a higher risk population based on age and co-morbidities.