Analysis of left ventricular function after emergency coronary artery bypass grafting for life-threatening ischaemia following primary revascularization.

OBJECTIVE

Severe ischemic injury in the first few hours following primary revascularization necessitates acute reoperation. To study the effect of emergency coronary artery bypass grafting, we followed 18 patients for up to 8 years, relating their changes of global and regional myocardial function during the acute event and after secondary revascularization to final outcome.

METHODS

A total of 16 patients with coronary artery bypass grafting (CABG) and 2 PTCA were treated for coronary heart disease between 1989 and 1993 and experienced life-threatening ischemic events (94% cardiogenic shock, 39% ventricular fibrillation, 67% ischemic electrocardiograph (ECG) changes) within 2.3+/-1.6 h after primary revascularization. Reoperation was carried out 1.0+/-1.3 h after the occurrence of acute ischemia. Serial echoes were obtained during the acute event and after reoperation as well as during the follow-up period.

RESULTS

Of the 18 patients, 8 are currently alive, 5 died within 30 days and 4 within the 1st year. There was one late death 5 years after surgery. Global and regional wall motion was evaluated using short axis views of transesophageal echoes taken during the acute event and after secondary revascularization, and compared with transthoracic echoes in long-term survivors up to 5 years after surgery. During the acute event left ventricular ejection fraction (LVEF) was reduced in 83% of the patients and improved significantly after reoperation (chi2 = 11.74, df= 2, P < 0.01). As to regional wall motion, 50% of the segments in non-revascularized areas remained abnormal. Regional wall motion after reoperation was significantly better in the surviving patients compared with patients dying in the post-operative course (chi2 = 6.23, df= 1, P < 0.05). The revascularization score ( > 75%) of abnormal contracting segments during the acute ischemic event was a significant determinant for long-term survival.

CONCLUSION

We conclude that patient outcome is determined by the severity of regional wall motion abnormality during the acute ischemic event, the aggressiveness of the attempt to revascularize these perfusion territories and their improvement after revision. Long-term survival reflects, therefore, the extent of emergency revascularization and therefore the ability to identify ischemic perfusion territories for surgical strategy planning.