P-022 Association of smoking with increased risk of stroke or transient ischemic attack in the treated vessel territory following angioplasty and stenting for intracranial atherosclerotic disease

Purpose Intracranial atherosclerotic disease (ICAD) is one of the leading causes of ischemic stroke worldwide. Percutaneous transluminal angioplasty (PTA) and stenting has emerged as a treatment for ICAD since there is a significant risk of recurrent ischemic stroke with medical management. We present data of our experience with PTA and stenting for ICAD and demonstrate an association between past or current smoking and risk of recurrent stroke or transient ischemic attack in the treated vessel territory. Materials and Methods A retrospective review was conducted of 29 patients with symptomatic ICAD >70% who failed medical management and underwent angioplasty and stenting between July 2005 and August 2010. Patients were classified as symptomatic or asymptomatic. Symptomatic patients were defined as having a recurrent ischemic stroke or transient ischemic attack in the vascular territory of the treated vessel. Rates of in-stent restenosis, hypertension, history of smoking or current smoking, diabetes, hyperlipidemia and location of stenosis were compared in symptomatic vs asymptomatic patients. The effects of past or current smoking, hypertension, diabetes and hyperlipidemia on rates of in-stent restenosis were also compared. Results 29 patients with symptomatic intracranial stenosis >70% underwent angioplasty and stenting of intracranial lesions; 26 returned for clinical follow-up. The procedural success rate, defined as more than 50% endoluminal revascularization of the stenotic lesion after stent deployment was 97%. There were no procedural complications. The average period of clinical and radiographic follow-up was 1.8 years. Three patients had strokes (11.5%) and two patients had a transient ischemic attack (7.7%) in the territory of the affected vessel over the follow-up period. The risk of ischemic stroke, transient ischemic attack, intracerebral hemorrhage or death at 30 days was zero. The incidence of ischemic stroke in the treated vessel territory was 7.7% at 6 months and 11.5% at 1 year. The incidence of ischemic stroke or TIA in the affected vessel at 1 year was 15.4%. From 1 year after the procedure to the end of the follow-up period there were no further strokes and only one TIA in the affected vessel territory. Of the modifiable risk factors, only past or current smoking had a statistically significant association with the symptomatic group (p=0.020). Diabetes, hypertension and hyperlipidemia were not associated with symptomatic patients. In-stent restenosis was also associated with the symptomatic group (p=0.028). There was no association of past or current smoking, hypertension, diabetes or hyperlipidemia with in-stent restenosis. Conclusions Of the vascular risk factors studied, past or current history of smoking was associated with recurrent ischemic stroke or transient ischemic attack in a treated vessel territory following successful PTA and stenting in ICAD. There was no association of smoking, hypertension, diabetes or hyperlipidemia with in-stent restenosis. Despite the relatively small number of patients, this study emphasizes the importance of smoking cessation in patients with ICAD undergoing angioplasty and stenting and also demonstrates that former smokers have higher risk of recurrent ischemia and should be risk-stratified accordingly.