Purpose: Myocardial infarction and other comorbidities contribute to complications after carotid endarterectomy (CEA). However, because the combined stroke and death rate after CEA is less than 5%, even relatively large series have small numbers of adverse events that preclude a detailed analysis of the association between the outcome and the patient factors, such as comorbidity and age. We sought to overcome this limitation by studying patients who underwent CEA in a large random sample of Medicare beneficiaries.
Methods: We used a database that contained a 20% random sample of all Medicare beneficiaries to identify patients who underwent CEA between the years 1988 to 1990 (n = 22,165), and we followed these cases until 1992. With multivariate logistic regression and Cox proportional hazards regression models, we examined the impact of age, race, gender, geographic location, hospital characteristics, and comorbidity, including acute myocardial infarction (AMI) and congestive heart failure (CHF), on the risk of stroke and death after CEA.
Results: AMI and CHF had the greatest negative impact on the long-term survival rates (adjusted hazard ratio [HR]: 2.40, P < .0001, and 2.85, P < .0001, respectively). Other variables with a significant impact on the long-term survival rates were an age of >80 years (HR, 2.16; P < .0001), an acute stroke (HR, 1.51; P < .0001), diabetes mellitus (DM; HR, 1.52; P < .0001), and male sex (HR, 1.32; P < .0001). In addition, AMI, CHF, DM, and advanced age were associated with an increased risk of perioperative stroke and death.
Conclusion: Patients with AMI, CHF, DM, and an age of >80 years have diminished perioperative and long-term survival rates after CEA. These results may alter the risk/benefit analysis for such patients, especially those with asymptomatic disease.