Assessment of left ventricular function during off-pump coronary artery bypass surgery

Left ventricular function is commonly impaired following cardiopulmonary bypass and cardioplegic arrest. Off-pump coronary artery bypass surgery (OPCABG) offers promise of better myocardial protection, although the effect of multiple regional ischemic events on global myocardial function is unknown. Twenty-eight patients undergoing multivessel OPCABG were assessed with transesophageal echocardiography and pulmonary artery catheterization prior to and following revascularization. Both load-dependent and relatively load-independent measurements of systolic and diastolic performance were measured. Mean +/- SD age was 62+/-8.3 years, grafts performed were 3.8+/-1.6, and 28% of patients had fractional area change (FAC) <50%. Blood pressure was lower following OPCABG associated with a fall in systemic vascular resistance. There was no difference in measurements of systolic functional FAC, cardiac index, or afterload-corrected FAC. Diastolic function appeared to improve based on mitral inflow and pulmonary vein Doppler measurements, but this occurred at a significantly lower pulmonary capillary wedge pressure and end-diastolic area. No change in diastolic function was found using less load sensitive indices of diastolic function (color M-mode Doppler, tissue Doppler and instantaneous end-diastolic stiffness). Left ventricular systolic and diastolic function is preserved following multivessel OPCABG.