Aim: Acute coronary syndrome (ACS) patients undergoing offpump coronary artery bypass (OPCAB) often require intra-aortic balloon pump (IABP) support. Indications and timing of IABP insertion are controversial. A study was done to determine criteria for predicting the use of IABP in these patients.
Method: 46 patients were operated for ACS within one week of event between January 2004 and July 2006 and categorized into, Unstable angina (UA) (n=25), with ongoing pain after late admission to emergency room (>6 hours) and acute myocardial infarction (AMI) (n=21) with AMI within 7 days of event.
Results: There was no statistical difference in the demographic data of two groups. UA group had higher incidence of mitral regurgitation preoperatively (p = 0.004) which improved postoperatively (p = 0.1). IABP was usedpreoperatively more in AMI group (10 vs. 6, p = 0.03). Multivariate analysis revealed pressure ratio of mean pulmonary and systemic arteries as a predictor of IABP use (p = 0.01, odds ratio 19.4, 95% CI 1.9-190). There is a significant positive correlation (r = 0.519) between IABP use and ratio of mean pulmonary and systemic arterial pressures (p = 0.004) with cutoff value at 0.40.
Conclusion: Ratio of mean pulmonary and systemic artery of > 0.40 indicates preoperative use of IABP to complete the operation safely.