The Recovery of Left Ventricular Function after Coronary Artery Bypass Grafting in Patients with Severe Ischemic Left Ventricular Dysfunction: Off-pump Versus On-pump

Kim, Jae Hyun; Na, Chan Young; Kim, Gun Gyk; Baek, Man Jong; Oh, Sam Sae; Kim, Chong Whan

Abstract

BACKGROUND: Adverse effects of cardiopulmonary bypass can be avoided by "Off-pump" coronary artery bypass (OPCAB) surgery. Recent studies have reported that OPCAB had the most beneficial impact on patients at highest risk by reducing bypass-related complications. The purpose of this study is to compare the outcome of OPCAB and conventional coronary artery bypass grafting (CCAB) in patients with poor left ventricular (LV) function. MATERIAL AND METHOD: From March 1997 to February 2004, seventy five patients with left ventricular ejection fraction (LVEF) of 35% or less underwent isolated coronary artery bypass grafting at our institute. Of these patients, 33 patients underwent OPCAB and 42 underwent CCAB. Preoperative risk factors, operative and postoperative outcomes, including LV functional change, were compared and analysed. RESULT: Patients undergoing CCAB were more likely to have unstable angina, three vessel disease and acute myocardial infarction among the preoperative factors. OPCAB group had significantly lower mean operation time, less numbers of total distal anastomoses per patient and less numbers of distal anastomoses per patient in the circumflex territory than the CCAB group. There was no difference between the groups in regard to in-hospital mortality (OPCAB 9.1% (n=3) Vs. CCAB 9.5% (n=4)), intubation time, the length of stay in intensive care unit and in hospital postoperatively. Postoperative complication occurred more in CCAB group but did not show statistical difference. On follow-up echocardiography, OPCAB group showed 9.1% improvement in mean LVEF, 4.3 mm decrease in mean left ventricular end-diastolic dimension (LVEDD) and 4.2 mm decrease in mean left ventricular end-systolic dimension (LVESD). CCAB group showed 11.0% improvement in mean LVEF, 5.1 mm decrease in mean LVEDD and 5.5 mm decrease in mean LVESD. But there was no statistically significant difference between the two groups.
CONCLUSION
This study showed that LV function improves postoperatively in patients with severe ischemic LV dysfunction, but failed to show any difference in the degree of improvement between OPCAB and CCAB. In terms of operative mortality rate and LV functional recovery, the results of OPCAB were as good as those of CCAB in patients with poor LV function. But, OPCAB procedure was advantageous in shortening of operative time and in decrease of complications. We recommend OPCAB as the first surgical option for patients with severe LV dysfunction.