Effect of coronary bypass surgery and valve replacement on left ventricular function: assessment by intraoperative two-dimensional echocardiography.

Intraoperative two-dimensional echocardiography (2DE) was performed in 15 patients during coronary artery bypass grafting (CABG) and in 14 patients during aortic (AVR) or mitral valve replacement (MVR) before and immediately after cardiopulmonary bypass by means of a 3.5 MHz transducer. Left ventricular ejection fraction (LVEF), end-diastolic (LVEDV) and end-systolic (LVESV) volumes were measured by a light pen system and biplane Simpson's rule from short-axis and apical two-chamber views. In seven patients with CABG and new abnormal Q waves or greater than 5% MB to total CPK ratio postoperatively, the mean LVEF decreased significantly (from 52 +/- 10 to 43 +/- 12%, p = 0.005). Patients undergoing MVR for mitral regurgitation showed, a significant decrease in LVEF (from 63 +/- 10 to 42 +/- 23%, p less than 0.025) and LVEDV (from 166 +/- 34 to 147 +/- 44 ml, p less than 0.05). Mean LVEF also decreased after AVR for aortic regurgitation (from 46 +/- 16 to 26 +/- 15%, p less than 0.05). Six patients with valve replacement and postoperative hypotension had the greatest decrease in intraoperative LVEF (from 50 +/- 12 to 24 +/- 10%, p less than 0.005). It is concluded that: Intraoperative 2DE can be used to assess immediate changes in left ventricular function after CABG or valve replacement. LVEF decreases significantly immediately after AVR for aortic regurgitation and MVR for mitral regurgitation. Intraoperative 2DE may identify those patients who can benefit from inotropic support in the immediate postoperative period after valve replacement.