Background: The aim of the current study was to compare hemodynamic performances of the Carbomedics^® and On- X^® mechanical bileaflet heart valves in the early postoperative period in patients undergoing mitral valve replacement (MVR).

Methods: Thirty patients who underwent MVR operations were randomly divided into two groups. Carbomedics^® and On-X^® mechanical bileaflet mitral valves were implanted in the first group (n=15) and the second group (n=15) of patients, respectively. Hemodynamic measurements were done by echocardiography in the preoperative period and three months after the operation.

Results: There were no statistically significant differences between the two groups regarding pre- and postoperative changes that occured in left ventricular end diastolic diameter, left ventricular end sistolic diameter, left atrium diameter, pulmonary artery pressure, ejection fraction and fractional shortening (p>0.05). However, performance index in the Carbomedics^® group was higher than that in the On-X^® group (0.96±0.15 vs 0.73±0.10) and the difference was statistically significant (p<0.05). Transvalvular peak pressure gradient in the Carbomedics^® group was higher than that in the On-X^® group (14.20±3.14 vs 11.07±2.89) and the difference was also statistically significant (p<0.05). There was no statistically significant difference for effective orifice area and transvalvular mean pressure gradient between the two groups postoperatively (p>0.05).

Conclusions: When echocardiographic data of the On-X^® and Carbomedics^® mitral mechanical heart valves were compared in the early postoperative period, similar hemodynamic performances were found. We propose that the On-X^® heart valve, which has been introduced into clinical use more recently than Carbomedics^®, can be used safely in MVR operations.

Keywords : Heart valve diseases/surgery; heart valve prosthesis implantation