A United States Population-Based Study on Clinical Outcomes Following Primary Carotid Endarterectomy: Who and When?

Abstract

Introduction: Carotid Endarterectomy (CEA) is widely recognized as effective in significantly reducing the risk of recurrent stroke emanating from extracranial carotid atherosclerosis and approximately 140,000 carotid endarterectomies are performed annually in the United States (US). As such, data are scarce on the prevalence and clinical outcomes of CEA across different age groups. This study aimed to determine and analyze the prevalence, demographic and clinical outcomes of CEA across six decades of life. Methods: Data on 40,276,240 patients were abstracted from discharge data obtained from the Nationwide Inpatient Sample (NIS) database, a part of the Healthcare Cost and Utilization Project (HCUP) of the Agency for Healthcare Research and Quality (2004-2008). Demographic and clinical characteristics of patients undergoing CEA as the primary procedure were abstracted including age, gender, elective or non-elective admission, comorbidities, Length of Stay (LOS), secondary procedures, NIS severity of illness and risk of mortality class, complications and mortality. CEA outcomes were compared across six decades of life starting at age 41. Categorical variables were compared using the Chi-square test, and the Student’s t-test was used to compare continuous variables. Results: 118,947 patients who underwent CEA as their primary procedure were identified. Caucasians accounted for 67.1% of the population. The overall mean age was 71.2 ± 9.5 years, with a Male: Female ratio of 1.3:1. Nineteen percent of patients had non-elective admission, with the highest percentage (29.5%) in those >91 years old. Over three percent of patients had a prior stroke. The overall number of CEA performed peaked in the 8th decade of life (38.4%). The most common co-morbidities were hypertension, diabetes mellitus, and chronic pulmonary disease. Mean LOS was 3.3 days. Forty-two percent of all cases were performed in a teaching hospital, with the percentage increasing with advancing age. The overall mortality and stroke rates were 0.4% and 0.9%, respectively, and these rates were highest in the oldest patients (>91 years). The overall myocardial infarction rate was 0.8% which was highest incidence in the 7th and 9th decades (1.1%). On multivariate analysis, age >80 years (Odds Ratio (OR), 2.9; 95% Confidence Interval (CI), 1.1 - 8.0), Non-white race (OR, 1.7; CI, 1.1 - 2.7), Charlson co-morbidity index score of 1 - 5 (OR, 1.7; CI, 1.3 - 2.4), carotid artery stenosis with stroke at presentation (OR, 1.7; CI, 1.1 - 2.5), Congestive Heart Failure (CHF) (OR, 3.7; CI, 2.8 - 4.8) and renal failure (OR, 2.2; CI, 1.6 - 3.1) were independent risk factors associated with increased CEA mortality. Conclusions: The percent of patients over 80 years is the fastest-growing segment of the US population, and CEA is an increasingly commonly procedure in elderly patients with a low mortality rate across all age groups. On a population level age >80, non-Caucasian race, the presence of specific co-morbidities (i.e., Stoke at presentation, congestive heart failure, renal failure), and a high Charlson co-morbidity index score are independent predictors of an increased CEA related mortality.