Mitral valve replacement with chordal preservation in a rheumatic population

Background and aim of the study: Mitral valve replacement (MVR) with preser vation of the subvalvular apparatus may maintain postoperative left ventric ular (LV) function better than conventional MVR. A prospective study was un dertaken to assess the advantages of chordal preservation in rheumatic pati ents undergoing isolated MVR. Methods: Between January 1996 and January 1999, 240 patients with rheumatic etiology and normal LV ejection fraction (>50%) underwent isolated MVR usi ng a St. Jude Medical prosthesis. Patients were allocated to two groups: in group I (n = 168), both the anterior and posterior chordae were preserved; in group II (n = 72), the entire native mitral valve apparatus was excised . Patients from both groups were evaluated postoperatively (mean 12.5 month s) by echocardiography and treadmill testing. Results: Demographic and clinical profiles were comparable in both groups. There were three early deaths in group I, and one in group II. There were n o late deaths. One patient in group I required reoperation for a stuck mitr al prosthesis. LV function (ejection fraction >50%) was better in group I ( 94%) than in group II (82%) (p <0.05). No patient in either group had LV ou tflow tract obstruction on echocardiography. Patients in group I showed bet ter exercise performance on treadmill (Bruce protocol): 92% of group I pati ents versus 88% of group ZI patients (p >0.05) completed stage I; 16% of gr oup I patients, but no group II patients, were able to complete stage IV (p <0.05). Conclusion: Mitral valve replacement with preservation of the subvalvular a pparatus maintains LV function, and does not cause LV outflow tract obstruc tion.