Partial left ventriculectomy: which patients can be expected to benefit?

BACKGROUND: Although some patients with end-stage heart disease will benefit from a partial left ventriculectomy, no criteria have been found for identifying this group preoperatively. Our experience with partial left ventriculectomy at two institutions-the Texas Heart Institute in Houston, TX, USA, and Dedinje Cardiovascular Institute in Belgrade, Yugoslavia-showed a higher survival rate and better postoperative myocardial function in the Yugoslavian patients. METHODS: We reviewed data from 42 patients (21 at each center) who had idiopathic cardiomyopathy, a left ventricular end-diastolic dimension of more than 70 mm, wall thickness of 1 cm or greater, and New York Heart Association class III or IV symptoms. The only significant difference in preoperative status between the two groups was duration of symptoms. Histologic specimens, blinded as to origin, were graded with regard to myocyte hypertrophy, cytoplasmic vacuolation, and fibrosis. Computer-assisted myocyte and nuclear morphometry was also performed. RESULTS: Immediately postoperatively, there were no significant intergroup differences in the reduction in cardiac dimension or in corrections of mitral regurgitation. During 6-month follow-up, however, the Texas Heart Institute patients had a lower cardiac index (1.8 versus 3.0 L x min(-1) x m(-2); p = 0.001) and left ventricular ejection fraction (24% versus 34%; p = 0.006) than the Dedinje Cardiovascular Institute patients. The Texas Heart Institute patients differed from the Dedinje Cardiovascular Institute patients in the degree of severe or moderate changes in myocyte hypertrophy (90% versus 29%; p = 0.0003) and fibrosis (71% versus 29%; p = 0.006), as well as in the measurements of median myocyte diameter (35 +/- 7 microm versus 27 +/- 4 microm; p = 0.0002) and median nuclear size (15 +/- 4 microm versus 12 +/- 2 microm; p = 0.0029). CONCLUSIONS: In the Texas Heart Institute patients, the significant intergroup difference in clinical outcome may have been related to increased myocyte hypertrophy and fibrosis. Further studies should be performed to determine the usefulness of these criteria in selecting patients for partial left ventriculectomy.