Serial changes in left ventricular function after correction of chronic aortic regurgitation: Dependence on early changes in preload and subsequent regression of hypertrophy

Abstract

Surgical correction of chronic aortic regurgitation generally results in a substantial decrease in left ventricular (LV) volume and mass. To assess the functional significance of these structural changes, serial noninvasive tests of LV function from 23 patients were examined after aortic valve replacement. Three independent tests of LV function were used: (1) the ratio of the LV preejection period (PEP) to the LV ejection time (LVET), (2) the echocardiographic fractional increase in LV wall thickness (FT), and (3) the mitral E point to septal separation (ESS). Studies were performed before surgery and at 0.3 (early), 3 to 6 (mid), and 9 to 12 (late) months after surgery. In the early postoperative studies, LV end-diastolic dimension decreased to normal or near-normal and the PEP/LVET ratio increased substantially in 17 patients. Ten of the 17 (group 1) had complete regression of LV hypertrophy and the average values for all 3 indexes of LV function were normal at the time of the late postoperative study (PEP/LVET = 0.41 ± 0.05, FT = 73 ± 14%, ESS = 6.2 ± 0.9 mm). Seven patients (Group 2) with incomplete regression of LV hypertrophy showed borderline to moderately abnormal function indexes at the late study. Six patients had persistent LV enlargement and no postoperative regression of hypertrophy (Group 3). These patients did not show the substantial early changes in the function indexes observed in Groups 1 and 2; moreover, the indexes remained markedly abnormal at the time of the late postoperative study (PEP/LVET = 0.52 ± 0.10, FT = 47 ± 13%, ESS = 22.3 ± 7.2 mm). Patients in Group 3 had preoperative evidence of abnormal LV function which was more marked than that observed in Groups 1 and 2. Thus, the early postoperative changes in LV preload and the subsequent regression of LV hypertrophy are associated with evidence of early LV dysfunction and subsequent improvement. Postoperative LV enlargement and persistent LV hypertrophy are associated with persistent LV dysfunction. These serial data provide a framework for the rational timing and interpretation of postoperative ventricular function tests.