A systematic review of contralateral carotid stenosis progression after carotid endarterectomy

Objective: Progression of contralateral carotid artery stenosis after carotid endarterectomy (CEA) has been described by several authors. The aim of this study is to determine such disease progression and its related transient ischemic attacks (TIAs) or strokes by reviewing the existing literature. Methods: We performed a systematic literature review to select randomized controlled trials and observational studies reporting outcomes of patients treated by CEA and with concomitant contralateral carotid stenosis, regardless its degree of stenosis. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO registration number: CRD42019127595). The primary study end point was the progression of contralateral carotid artery stenosis after CEA, and the secondary end point was incidence of TIAs and strokes owing to contralateral carotid stenosis. Results: Seventeen studies were retrieved, reporting data on a total of 7679 patients who had undergone CEA, in particular they were one post hoc analysis of a randomized controlled trial, nine prospective, and seven retrospective observational studies. Among these patients, follow-up information on the contralateral carotid artery was available for 5454 cases. Disease progression was observed in 18% of patients: single class progression from mild (<50%) and from moderate (50%-70%) stenosis was observed in 15% and 23% of cases, respectively. We found 105 TIAs (4%) and 88 strokes (3%) among 2781 patients with stenosis progression, based on result from 11 studies. Conclusions: We found a progression of contralateral carotid stenosis in a significant number of patients treated with CEA and with baseline carotid stenosis. This systematic literature review suggests that patients with moderate contralateral carotid stenosis demonstrate more rapid progression to significant or symptomatic stenosis than patients with mild contralateral stenosis.