Carotid sinus reactions during carotid artery stenting: predictors, incidence, and influence on clinical outcome.

Carotid sinus reactions (CSR), defined as asystole >/= 3 sec and hypotension (systolic blood pressure </= 90 mm Hg), are frequent events during carotid artery stenting (CAS). Factors predisposing a patient to CSR as well as the impact of CSR on periprocedural complications have not yet been investigated in a prospective manner. The relationship between various clinical, morphologic, and procedural variables and the occurrence of CSR was examined among 105 consecutive patients undergoing successful CAS. After predilatation with a compliant balloon, tubular-slotted stents were used in all patients. No CSR occurred in 63 (60%) patients, whereas CSR developed in 42 (40%) patients. The most common type of CSR was asystole in combination with short-term hypotension without clinical symptoms. The most important predictor of CSR was bifurcation location of carotid stenosis (bifurcation > ostial > isolated internal carotid artery; P < 0.001). The other independent predictors were presence of contralateral stenosis (P < 0.02), length of stenosis (P < 0.03), and balloon-to-artery ratio (P < 0.02). Occurrence of CSR was unrelated to periprocedural cerebral or cardiovascular complications (7.1% vs. 9.5%; NS). We conclude that CSR occurs frequently (40%) during CAS. Bifurcation location of stenosis is the most important predictor of CSR. CSR does not increase the risk of periprocedural complications. Copyright 2003 Wiley-Liss, Inc.