Mitral reconstruction in cardiomyopathy.
Functional mitral regurgitation (MR) is a significant complication of end-stage cardiomyopathy, and may affect most heart failure patients as a pre-terminal or terminal event as it develops secondary to a change in the annular-ventricular apparatus and altered ventricular geometry; this results in incomplete leaflet coaptation.. Historically, surgery in MR patients was mitral valve replacement, but the adverse effects on LV systolic function of interrupting annulus-papillary muscle continuity was poorly understood. At the University of Michigan (1993-2000), 140 patients with end-stage cardiomyopathy and refractory MR underwent mitral valve repair with an undersized flexible annuloplasty ring. All were in NYHA class III/IV despite receiving maximal medical therapy, and had severe LV systolic dysfunction (ejection fraction (EF) <25%). Overall operative mortality was 5%. There were five 30-day mortalities (one intraoperative death due to right ventricular failure, one cardiac failure, one stroke, two multisystem organ failure). Five patients required intra-aortic balloon pump IABP support, but no patients required a LV assist device. Mean follow up was 38 months (range: 1-68 months); one- and two-year actuarial survival was 80% and 70%, respectively. There were 26 late deaths. At postoperative echocardiography the mean transmitral gradient was 3 +/- 1 mmHg (range: 2-6 mmHg). At two-year follow up, all patients were in NYHA class I/II, with mean EF 26%. NYHA class was improved in all patients, and all reported subjective improvement in functional status. Improvements were shown in LV EF, cardiac output, and end-diastolic volumes, with reduced sphericity index and regurgitant fraction. Though significant undersizing of the mitral annulus was used to over-correct for the zone of coaptation, no mitral stenosis was induced, nor was any systolic anterior motion (SAM) noted. SAM was avoided due to widening of the aortomitral angle and increased LV size seen in myopathic patients. In conclusion, surgical therapies of heart failure are rapidly expanding and evolving. As a result of improvements in preoperative selection, intraoperative techniques and postoperative care, high mortality and morbidity after surgical intervention in patients with end-stage heart disease no longer apply. By combining operative techniques with optimal medical management of heart failure, good outcome can avoid or postpone transplantation. This strategy will help to preserve the limited number of donor organs for those patients with no other surgical or medical alternatives.
Bolling
Steven F
SF
Cardiac Surgery, University of Michigan, USA.
D009202:Cardiomyopathies / Q000150:complications* / Q000401:mortality / Q000601:surgery*; D006801:Humans; D008943:Mitral Valve / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000209:etiology* / Q000401:mortality / Q000601:surgery*; D015996:Survival Rate