Association between minor and major surgical complications after carotid endarterectomy: Results of the New York Carotid Artery Surgery study

Objective: Most studies on outcomes of carotid endarterectomy (CEA) have focused on the major complications of death and stroke. Less is known about minor but more common surgical complications such as hematoma, cranial nerve palsy, and wound infection. This study used data from a large, population-based cohort study to describe the incidence of minor surgical complications after CEA and examine associations between minor and major complications. Methods: The New York Carotid Artery Surgery (NYCAS) study examined all Medicare beneficiaries who underwent CEA from January 1998 to June 1999 in NY State. Detailed clinical information on preoperative characteristics and complications ≤30 days of surgery was abstracted from hospital charts. Associations between minor (cranial nerve palsies, hematoma, and wound infection) and major complications (death/stroke) were examined with χ² tests and multivariate logistic regression. Results: The NYCAS study had data on 9308 CEAs performed by 482 surgeons in 167 hospitals. Overall, 10% of patients had a minor surgical complication (cranial nerve (CN) palsy, 5.5%; hematoma, 5.0%; and wound infection, 0.2%). Cardiac complications occurred in 3.9% (myocardial 1.1%, unstable angina 0.9%, pulmonary edema 2.1%, and ventricular tachycardia 0.8%). In both unadjusted and adjusted analyses, the occurrence of any minor surgical complication, CN palsy alone, or hematoma alone was associated with 3 to 4-fold greater odds of perioperative stroke or combined risk of death and nonfatal stroke (P < 0.0001). Patients with cardiac complications had 4 to 5-fold increased odds of stroke or combined risk of death and stroke. Conclusion: Minor surgical complications are common after CEA and are associated with much higher risk of death and stroke. Patient factors, process factors, and direct causality are involved in this relationship, but future work will be needed to better understand their relative contributions.