To determine the effects of myocardial revascularization on decreased left ventricular diastolic compliance consequent to chronic stable coronary artery disease, 15 patients with patent coronary artery bypass grafts (Group I) were compared with 8 patients with occluded grafts (Group II) studied before and after operation. In addition, eight normal patients served as controls. Left ventricular diastolic compliance was assessed by: (1) total observed diastolic compliance: stroke volume (V) related to left ventricular diastolic pressure (P) change (ΔV/ΔP) normalized for end-systolic volume; (2) left ventricular stiffness index of passive elastic modulus (a = slope of ΔV/ΔP related to mean left ventricular diastolic pressure); and (3) fractional pattern of left ventricular filling. All patients had normal sinus rhythm and none had preoperative or postoperative mitral regurgitation. The two groups with coronary disease were well matched preoperatively for ventricular function, volumes, mass, segmental contraction and compliance. Ejection fraction increased in Group I (0.56 preoperatively to 0.65 postoperatively, P < 0.05) but was unchanged in Group II (0.63 to 0.61, P > 0.05). Postoperative indexes of left ventricular compliance improved in Group I: (1) 0.110 to 0.150 (P < 0.05); (2) 0.030 to 0.019 (P < 0.05); and (3) 37 to 30 percent filling during last one third of diastole (P < 0.05). These indexes were unchanged postoperatively in Group II: (1) 0.109 to 0.102 (P > 0.05); (2) 0.033 to 0.039 (P > 0.05); and (3) 36 to 41 percent (P > 0.05). Compliance indexes were not altered (P > 0.05) in a subset of seven patients in Group I with preoperative or intercurrent myocardial infarction. Thus, this investigation demonstrates the relatively reversible nature of abnormal left ventricular compliance after successful coronary artery bypass surgery in certain patients with ischemic heart disease.
All Science Journal Classification (ASJC) codes
- Cardiology and Cardiovascular Medicine