Risk factors for complications after carotid endarterectomy--a population-based study.

OBJECTIVES: The overall benefit of carotid endarterectomy (CEA) is dependent on the outcome from the procedure. However, many reports are from selected centres and not population-based. The aim of this study was to assess the 30-day complication rate for a whole country and also to determine independent risk factors for serious complications.
MATERIALS AND METHODS: One thousand five hundred and eighteen CEA were retrospectively reviewed, covering principally all the CEAs in Sweden, during a three year period. Indications for surgery were; minor stroke 34%, TIA 34%, amaurosis fugax 18%, asymptomatic 11% and others 3%. Data were collected from the Swedish Vascular Registry (Swedvasc). Combined cohort and case-control methodology was used.
RESULTS: Registered complications were; 43 permanent strokes, 32 transient strokes (<30 days), 18 TIA/amaurosis fugax and 22 deaths (seven fatal stokes). In the cohort study, the 30-day permanent stroke and death rate were 4.3% (65/1518). Significant risk factors in multivariate analyses were the indication for surgery (minor stroke vs. other indications) (p=0.02, RR=1.38), diabetes (p=0.02, RR=1.41), cardiac disease (p<0.01, RR 1.43) and operation at a university hospital (p=0.02, RR=1.39). In the case-control study comparing the 65 cases of permanent stroke and/or death with 130 matched controls the only significant risk factor was contralateral occlusion (p<0.01, OR=5.27). One patient (1/130) with a permanent stroke was wrongly reported as a local neurological complication (facial paresis).
CONCLUSION: This national audit demonstrated population-based data on complication rates after CEA well comparable with previous randomised trials. The validity of the Swedvasc data was confirmed. Combined cohort and case-control methodology was useful in analysing risk factors for serious perioperative complications.