Relationship Between Blood Pressure and Stroke Recurrence in Patients With Intracranial Arterial Stenosis

Background— Many clinicians allow blood pressure to run high in patients with intracranial stenosis to protect against hypoperfusion. We sought to determine whether higher blood pressure decreases the risk of stroke in these patients. Methods and Results— Data on 567 patients in the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial were analyzed. Time to ischemic stroke and stroke in the same territory of the stenotic vessel was compared in patients grouped by mean systolic blood pressure (SBP) and mean diastolic blood pressure (DBP) during the study. Additional analyses were based on severity and location of stenosis. Ischemic stroke risk increased with increasing mean SBP and DBP on univariate analysis ( P <0.0001, P <0.0001) and after adjustment for risk factors ( P =0.0008, P <0.0001). Elevated mean SBP and DBP also resulted in increased risk of stroke in the territory in univariate ( P =0.0065, P <0.0001) and adjusted ( P =0.0002, P =0.0005) analyses. The increased risk of stroke with increasing SBP was driven largely by patients in the highest SBP group. Patients with moderate (<70%) stenosis had increased risk of stroke ( P <0.0001, P =0.003) and stroke in the territory ( P =0.0002, P =0.010) with increased SBP and DBP. Patients with severe (≥70%) stenosis had increased risk of stroke and stroke in the territory with elevated DBP ( P =0.004, P =0.004). Conclusions— In patients with intracranial stenosis, higher blood pressure is associated with increased (not decreased) risk of ischemic stroke and stroke in the territory of the stenotic vessel. These findings argue strongly against the common clinical practice of maintaining high blood pressure in patients with intracranial stenosis

Prevalence and Prognosis of Coexistent Asymptomatic Intracranial Stenosis

BACKGROUND AND PURPOSE: There are limited data on the prevalence and prognosis of asymptomatic intracranial stenosis (AIS). METHODS: Baseline cerebral angiograms and MR angiograms were used to determine AIS (50% to 99%) coexistent to symptomatic intracranial stenosis for patients enrolled in the Warfarin-Aspirin Symptomatic Intracranial Disease study. RESULTS: Coexisting AIS were detected in 18.9% (n=14/74) of patients undergoing 4-vessel cerebral angiography and 27.3% (n=65/238) of patients undergoing MR angiogram. During a mean follow-up period of 1.8 years, no ischemic strokes were attributable to an AIS on cerebral angiography and 5 ischemic strokes (5.9%, 95% CI: 2.1% to 12.3%) occurred in the AIS territory on MR angiogram (risk at 1 year=3.5%, 95% CI: 0.8% to 9.0%). CONCLUSIONS: Whereas the prevalence of coexisting AIS (50% to 99%) in patients with symptomatic stenosis is high, the risk of stroke from these asymptomatic stenoses is low

Abstract 122: Stroke Patterns And Causative Mechanisms Of Ischemia In Patients With Symptomatic Intracranial Atherosclerotic Stenosis

Background/objectives: Putative mechanisms of stroke in intracranial atherosclerotic stenosis (ICAS) include hypoperfusion, artery-to-artery embolism or perforator occlusion, each of which may be characterized by different stroke patterns on neuroimaging. Our aims are to determine: 1) the different stroke patterns in patients with ICAS; 2) the correlation of angiographic factors (collaterals, degree and location of stenosis) with stroke patterns; and 3) if the patterns of recurrent stroke in the same territory are similar to qualifying strokes. Methods: From the WASID dataset, we selected patients with a stroke at baseline who had conventional angiographic information on collaterals (n=136), and patients with a recurrent stroke in the territory during follow-up (n= 47). We categorized stroke patterns as follows: for anterior circulation-subcortical (SC), cortical (C), territorial (T), borderzone (BZ) and multiple (M); for posterior circulation,-subcortical (SC), cortical (C), cerebellar (CB) and multiple (M). We defined an embolic mechanism if C, T, CB or multiple were present. The association between stroke patterns and collateral grade assessment (ASITN/SIR), location and degree of stenosis, and treatment assignment (warfarin vs aspirin) was analyzed using Chi-Square and McNemar’s tests. Results: Anterior circulation patterns (n=72) at baseline were: 14(19%) SC, 5(7%) T, 2(29%) C, 12(17%) BZ and 20(28%) M. All isolated BZ stroke patterns were located in internal borderzone region. BZ pattern was equally distributed among patients with no collaterals (5/40=12%) vs. patients with collaterals (7/32=22%) (p= 0.29) and among patients with moderate (8/43=19%) vs. severe stenosis (4/29=14%) (p=0.59). Posterior circulation patterns (n= 64) at baseline were: 25(39%) SC, 5(8%) C, 10(16%) CB and 24(38%)M. Embolic stroke pattern at baseline was the most frequent (85/136=62.5%). Among patients with a recurrent stroke in the territory (n=47), embolic pattern was also the most frequent (32/47, 68%). The probability of having a recurrent embolic stroke pattern was related to stenosis degree (81% in severe vs 50% in moderate stenosis, p= 0.03), collateral grade (83% with collaterals vs 53% no collaterals, p= 0.09), and previous embolic stroke pattern (74 % who had baseline embolic stroke vs 25% who had baseline non-embolic stroke,p= 0.01). Having a recurrent embolic stroke pattern was not influenced by treatment assignment (67% treated with warfarin vs 69% treated with aspirin, p=0.85). Conclusions: Artery-to-artery embolism seems to be the most frequent mechanism of stroke in ICAS patients and was not modified by antithrombotic treatment. Isolated BZ infarcts were less frequent, and were not related to poor collaterals or more severe stenosis