Isolated Aortic Valve Replacement: The Impact of Patient-Prosthesis Mismatch on Early Mortality

Patient-prosthesis mismatch (PPM) occurs when the effective orifice area (EOA) of a prosthetic heart valve is too small relative to the patient's body size, leading to elevated postoperative gradients and potentially adverse clinical outcomes. It remains a significant topic of concern despite advances in prosthesis manufacturing technologies.  The primary objective of this study was to determine the prevalence of PPM and assess its impact on early (in-hospital) mortality following isolated surgical aortic valve replacement (AVR).  This retrospective study included 491 adult patients (≥18 years) who underwent isolated surgical AVR at University Hospital Center "Mother Teresa" in Tirana, Albania, from January 2007 to December 2023. Patients undergoing concomitant procedures (e.g., coronary artery bypass grafting (CABG), mitral surgery) were excluded. Both mechanical and bioprosthetic valves were included. Data were collected on general demographic characteristics, important intraoperative and postoperative times, and postoperative outcomes. Early mortality was defined as any in-hospital death occurring after the intervention. The indexed EOA (EOA-i) was used to classify PPM as severe (EOA-i < 0.65 cm²/m²), moderate (0.65 ˂ EOA-i  ≤ 0.85 cm²/m²), or none (EOA-i > 0.85 cm²/m²). EOA-i was calculated using prosthesis-specific reference EOAs provided by valve manufacturers. Mortality were assessed in relation to PPM severity.  Our study included 491 patients with a mean age of 62.28 ± 10.76 years. The majority of patients group (63.3%) were male, and 91.8% of the procedures were elective. Among them, 44.4% had moderate PPM and 11.0% had severe PPM. A total of eight early deaths (1.6%) occurred. Early mortality was significantly higher in the severe PPM group (3.7%) compared to the moderate (1.8%) and no PPM groups (0.9%) (p = 0.048, Fisher's exact test). In multivariate logistic regression, severe PPM was associated with increased odds of early mortality (odds ratio (OR) 15.62, 95% confidence interval (CI) 9.004-21.10, p = 0.050) after adjusting for valve type, body size, age and New York Heart Association (NYHA) class.  Severe PPM is strongly associated with increased short-term mortality following AVR. Implementing strategies to prevent PPM such as CT-based annulus sizing and annular enlargement during surgery is crucial for reducing postoperative mortality risks.