Hemodynamic instability during carotid artery stenting: the relative contribution of stent deployment versus balloon dilation

Hemodynamic instability may complicate carotid angioplasty and stenting in up to 40% of patients. The authors have previously demonstrated that primary self-expanding stent placement alone can gradually dilate severely stenosed carotid arteries without the use of balloons. The authors hypothesized that eliminating the balloon would reduce carotid baroreceptor stimulation, thereby decreasing the incidence of hemodynamic instability. Ninety-seven high surgical risk patients with symptomatic, severely stenosed carotid arteries were treated with the intention of using a self-expanding stent alone. Seventy-seven arteries (79%) were treated with stenting alone, and 20 required angioplasty (21%). Intraprocedural bradycardia (heart rate < 60 bpm) developed in 29 patients (38%) and hypotension (systolic blood pressure < 90 mm Hg) occurred in 1 patient (1%) treated with stenting alone. Fourteen patients (70%) who underwent angioplasty and stenting had bradycardia, and hypotension developed in 4 (20%). Atropine, glycopyrrolate, or vasopressors were required in 8% of patients who received stenting alone, compared to 30% of patients who underwent angioplasty. In the first 24 hours after treatment, hypotension or bradycardia developed in 25 patients (32%) who had undergone stent placement alone, and in 15 patients (75%) after stent placement and balloon angioplasty. There was no difference in the occurrence of intra- or postprocedural hypertension (systolic blood pressure > 160 mm Hg) between patients treated with stenting alone or stenting and balloons. Factors independently associated with hemodynamic depression included baseline heart rate and balloon use. Hemodynamic instability during and after carotid artery stenting was observed more frequently when balloon angioplasty was required than when stent placement was performed without concurrent balloon angioplasty.