Evaluating the Postoperative Complications of Coronary Artery Bypass Graft Surgery in the Elderly

Abstract

Background: Higher life expectancy and increased ischemic heart disease (IHD) have resulted in increasing number of the elderly patients undergoing cardiac surgeries. Age along with many other comorbidities influence the outcome of major surgeries in the elderly patients; hence, case selection before major surgeries is challenging. Objectives: The pure effect of age after adjusting for other major preoperative risk factors is on the center of debate in literature. Materials and Methods: In this retrospective study, 1377 patients who had undergone coronary artery bypass graft surgery (CABG) from June 2006 to August 2012 were included. Patients were categorized in two age groups: group A, < 70 and group B, ≥ 70 years old. Preoperative and postoperative variables were evaluated between these groups. Sex, diabetes mellitus (DM), hypertension (HTN), left ventricular ejection fraction (LVEF), and glomerular filtration rate (GFR) were assessed as preoperative factors. Postoperative complications such as sternal wound infection, nosocomial pneumonia, prolonged ventilation, atrial fibrillation (AF), and operation for rebleeding were registered to evaluate their association with age groups and preoperative comorbidities. Results: Patients in group B were more likely to have DM, HTN, and GFR < 60. In binary logistic regression, age ≥ 70 years was significantly associated with postoperative AF (OR = 2.26, 95% CI, 1.33-3.83) and prolonged ventilation (OR = 2.38, 95% CI, 1.2-4.5) while it was not associated with other complications. Nonetheless, the age was not a major risk factor for prolonged ventilation after adjustment for other main risk factors in multivariate analysis. AF was the most common complication of CABG in the elderly (age ≥ 70 years old). There was not a significant sex predilection in two age subgroups. In logistic regression, GFR > 60 mL/min/1.73 m2 was significantly associated with all complications except reoperation for bleeding, and it was a protective factor in those complications. After adjustment for age, in binary logistic, GFR < 60 mL/min/1.73 m2 was significantly associated with prolonged ventilation (P value = 0.036, OR = 2.2) and sternal wound infection (P value = 0.022, OR = 7.7). In multivariate analysis, the effect of GFR < 60 mL/min/1.73 m2 on AF was not significant. Left ventricular dysfunction (EF < 40%) was significantly associated with postoperative pneumonia (OR = 2.95; 95% CI, 1.2-7.6) and reoperation for bleeding (OR = 1.74, 95% CI: 1.09-2.85). Conclusions: CABG in the elderly patients is accompanied with higher morbidity. In addition, comorbidities are also major determinants of postoperative outcomes even after adjustment for age. Age alone is not a strong predictor of complications and preoperative health status of the elderly patient is also a major factor.