Heterogeneous immediate effects of partial left ventriculectomy on cardiac performance.

Abstract

Partial left ventriculectomy (PLV) is a novel surgical treatment for severe heart failure consisting of resection of a large wedge of myocardium to reduce wall stress and restore the normal mass-volume ratio. Although ejection fraction (EF) has been shown to improve after PLV, few other physiological data describing its immediate effects on left ventricular (LV) performance are available. Eight patients, 58+/-5 years old, with severe clinical heart failure and EF of 12+/-3% were studied before and immediately after PLV. LV performance was assessed by the predominantly load-insensitive measures of pressure-area relations with high-fidelity pressure catheters and transesophageal automated echocardiographic measures of cross-sectional area as a surrogate for volume. LV end-diastolic volume decreased from 200+/-60 to 89+/-17 mL, EF increased from 12+/-3% to 41+/-8%, and right ventricular (RV) fractional area change increased from 24+/-12% to 37+/-16% (all P<.05 versus before). Changes in pressure-area relations were variable: end-systolic elastance, 6.5+/-3.4 to 4.3+/-2.5 mm Hg/cm2 and preload recruitable stroke work, 33+/-16 to 34+/-19 mm Hg (P=NS versus before). End-diastolic stiffness increased from 0.13+/-0.06 to 0.19+/-0.07 mm Hg/cm2 (P<.05 versus before). Improvement in LV performance was inversely correlated with semiquantitative histological assessment of myocardial fibrosis and positively correlated with nuclear enlargement and hyperchromasia, indicative of myocyte hypertrophy. No long-term follow-up data were available. PLV resulted in reductions in LV volumes, increases in EF and RV ejection, but increases in LV stiffness. Estimates of LV performance revealed variable results associated with the degree of myocardial fibrosis. Further study of these effects in relation to patient outcome is warranted.