Semiquantitative histomorphometric analysis of myocardium following partial left ventriculectomy: 1-year follow-up.

Background: Although partial left ventriculectomy (PLV) may have beneficial clinical effects in patients with dilated cardiomyopathy (DCM), there are no reports on effects of PLV on myocardial histology. The objective of this study was to assess histological properties of the LV myocardium 1 year following PLV as compared to histology at the time of the operation. Methods: The study group consisted of 15 consecutive PLV survivors, predominantly male (13/15), aged 45±12 years. Surgical specimens and endomyocardial biopsies, taken 12 months postoperatively, were processed routinely and stained with Masson-trichrome. The following morphometric parameters were assessed semiquantitavely: (1) degree of hypertrophy and attenuation; (2) nuclear evidence of hypertrophy; (3) myofibrillar volume fraction; (4) degree of degenerative vacuolar changes; and (5) fibrosis volume fraction. Results Both New York Heart Association (NYHA) functional class and ejection fraction (EF) improved 12 months following surgery as compared to preoperative values (2.40±0.69 vs. 3.33±0.49, p<0.001, and 33.21±12.05% vs. 20.21±9.07%, p<0.001, respectively). Morphometric analysis demonstrated postoperative decrease in the degree of attenuation as compared to preoperative values (1.40±0.51 vs. 2.47±0.64, p<0.01), as well as a decrease in fibrosis volume fraction (2.07±0.80 vs. 2.67±0.49, p<0.001) and nuclear hypertrophy (1.27±0.46 vs. 1.67±0.62, p<0.05). On the other hand, postoperative increase in myofibrillar volume fraction (1.87±0.61 vs. 1.40±0.61, p<0.01) was noted. Conclusion One year postoperatively, PLV has favourable effects on myocardial morphology that parallels improvement in the patient's functional status and LV systolic function.