Effect of the Asymptomatic Carotid Atherosclerosis Study on carotid endarterectomy in Veterans Affairs medical centers

Objective: To examine the effect of the Asymptomatic Carotid Atherosclerosis Study on the volume of carotid endarterectomies (CEAs) performed in Veterans Affairs medical centers. Design: The data were retrospectively extracted from the Veterans Affairs Patient Treatment File for all patients undergoing CEA using the International Classification of Diseases, Ninth Revision, Clinical Modification procedural code 38.12. Data were classified into patient management categories to identify complications and to quantify the severity of illnesses and comorbidities. Setting: All 172 US Veterans Affairs medical centers. Patients: Veterans undergoing CEA during fiscal years 1993 through 1995. Main Outcome Measures: Procedural volume, mortality, and morbidity. Results: There was a 43.4% increase in the volume of CEAs performed in fiscal year 1995 despite a 4.6% decrease in the served inpatients and an 8.8% decrease in the inpatient surgical procedures. The monthly volume of CEAs increased (P<.001, r(2)=0.78) at the onset of the fiscal year (October 1994) immediately after the Asymptomatic Carotid Atherosclerosis Study clinical advisory. The volume of CEAs increased in every region of the country for all nonpsychiatric hospital classifications and for almost every surgeon subspecialty. Despite the increased volume, the operative mortality rate, the International Classification of Diseases, Ninth Revision, Clinical Modification-and patient management categories-based complication rates, and the patients' comorbidity and severity of illness indexes all remained unchanged. Conclusion: The dramatic increase in CEAs following the Asymptomatic Carotid Atherosclerosis Study clinical advisory suggests that the conclusions of the trial have been accepted by the medical community throughout the Veterans Affairs medical centers.