The stentless quadrileaflet bovine pericardial mitral valve: Echocardiographic assessment

Background ann aims of the study: Recently, a stentless chordally supported quadrileaflet mitral valve (QMV) bioprosthesis made of selected tanned bov ine pericardium treated to minimize calcification, has become available for clinical trial. The aim of this study was to report both the echocardiogra phic appearance and hemodynamic performance of this valve by means of echoc ardiography. Methods: The QMV was implanted in 22 patients (mean age 38 +/- 12 years) re quiring isolated mitral valve replacement for valve lesions not deemed suit able for repair. Echocardiography was performed preoperatively, and at one and three months postoperatively. Transthoracic echocardiography (TTE) was used to monitor mean instantaneous pressure gradient as calculated from the long modified Bernoulli equation, cardiac index (CI), pressure half-time a nd effective orifice area (EOA) using the Hatle and continuity equations. R egurgitation patterns were sought by color Doppler transesophageal echocard iography in all valves intraoperatively following valve implantation, and b y TTE in the outpatient clinic at follow up. Results: After a mean follow up of 8.3 months (range: 1 to 18 months), all patients were well and symptomatically improved. At three months postoperat ively, the mean pressure gradient ranged from 1.7 to 2.2 mmHg. The EOA was larger using the Hatle as compared with the continuity equation (2.4 +/- 0. 7 cm(2) versus 1.8 +/- 0.5 cm(2), respectively; p < 0.005). Mitral regurgit ation was trivial in 77% and mild in 14% of patients at 3 months after surg ery; moderate mitral stenosis was noted in one patient. The CI improved sig nificantly postoperatively (p < 0.005), and left ventricular function was m aintained. Conclusions: The hemodynamic performance of this novel prosthesis is favora ble. Although follow up is too short to assess durability, it is hoped that the unique design and improved valve preservation technique of this device will enhance long-term durability.