Objective: Perioperative myocardial infarction (PMI) is a well-described complication of coronary artery bypass grafting (CABG). Data on its effect on patients' subsequent health-related quality of life (QOL) and on other related consequences is deficient. The aim here was to evaluate in a prospective follow-up design the risk factors for and consequences of PMI and especially its possible impact on health-related QOL.
Methods: Comprehensive data, including preoperative risk profile, perioperative variables and postoperative morbidity up to discharge were collected of 501 CABG patients in the Heart Center of Tampere University Hospital and in all eighteen postoperative care hospitals. Eighty patients (16%) fulfilled ECG or cardiac enzyme criteria for PMI and they were compared to patients with no PMI. The RAND-36 Health Survey (RAND-36) was used as an indicator of QOL. The primary outcomes were change in physical component summary (PCS), mental component summary (MCS) and the eight dimensions of health-related QOL from the RAND-36. Symptomatic status was estimated according to New York Heart Association (NYHA) class. Assessments were made preoperatively and repeated 12 months later.
Results: Multivariate logistic regression analysis identified long cardiopulmonary bypass time (P=0.006) and high age (P=0.049) as independent predictors for PMI. Thirty-day mortality was adversely affected by PMI (6.3 vs 1.0%, P=0.001). In discharged patients, the occurrence of PMI did not affect 1-year survival adversely (98.7 vs 98.6%). The PMI patients showed significant (P<0.05) improvements in six of the eight dimensions of RAND-36, but they presented with a negative change in their 'general health' scores at the follow-up. All QOL scores improved significantly (P<0.001) among the patients without PMI. A highly significant (P<0.001) pattern of change was seen in the RAND-36 PCS and MCS scores in both groups although PMI patients showed significantly (P=0.002) smaller change in their PCS scores. Both groups showed similar freedom from anginal symptoms at 1 year (89.6 vs 90.1%) but in the PMI group later readmissions due to cardiac-related causes were more common (23 vs 10%, P=0.002).
Conclusions: PMI increases 30-day mortality and affects also adversely on later health-related QOL following CABG.