Improvement in diastolic left ventricular function after coronary artery bypass grafting as assessed by recordings of mitral annular velocity using Doppler tissue imaging

Abstract

The aim of the study was to evaluate the changes in diastolic function after coronary artery bypass grafting (CABG), using pulsed-wave Doppler tissue imaging (DTI). Fifty-three patients with coronary artery disease were studied before and 3 and 12 months after CABG. Using pulsed-wave DTI, the mitral annular velocities were determined at 4 sites in the left ventricle (LV). Patients were also examined with dobutamine stress echocardiography and myocardial scintigraphy before and 3 months after CABG. The conventional transmitral velocity profiles were unchanged after CABG. DTI showed a marked improvement in diastolic LV function after CABG (early diastolic velocity: 7.5+/-1.9, 8.2+/-1.7 and 9.3+/-2.7 cm/s before and 3 and 12 months after CABG, respectively, P < 0.01). The improvement in early diastolic velocity was more pronounced in patients showing no sign of residual ischemia in comparison to those with residual ischemia determined by myocardial scintigraphy (7.41+/-2.04 vs. 9.25+/-2.61 cm/s, P < 0.01 in the nonischemic group; 7.29+/-2.16 vs. 8.41+/-2.55 cm/s, n.s., in the ischemic group). Before CABG, a significant increase in the systolic velocity (6.4+/-1.3 vs. 8.7+/-2.5 cm/s, P < 0.001), but not the early diastolic velocity (7.6+/-1.9 vs. 8.0+/-2.2 cm/s), was noted during stress echocardiography. Three months after CABG, both the systolic (6.5+/-1.3 vs. 9.3+/-2.8 cm/s, P < 0.001) and the early diastolic velocities (8.1+/-1.8 vs. 10.3+/-2.2 cm/s, P < 0.001) improved during stress echocardiography. The results of the present study show that diastolic function improves at rest and under stress in patients after CABG. The improvement was seen only in patients without postoperative signs of reversible ischemia.