The Association of Blood Pressure and Collateral Circulation in Hyperacute Ischemic Stroke Patients Treated with Intravenous Thrombolysis

Abstract

Background: The integrity of collateral circulation is a major prognostic factor in ischemic stroke. Patients with good collateral status have larger penumbra and respond better to intravenous thrombolytic therapy. High systolic blood pressure is linked with worse clinical outcome in patients with acute ischemic stroke treated with intravenous thrombolytic therapy. We studied the effect of different blood pressure parameters on leptomeningeal collateral circulation in patients treated with intravenous thrombolytic therapy (<3 h) in a retrospective cohort. Methods: Anterior circulation thrombus was detected with computed tomography angiography and blood pressure was measured prior to intravenous thrombolytic therapy in 104 patients. Baseline clinical and imaging information were collected. Group comparisons were performed; Collateral Score (CS) was assessed and entered into logistic regression analysis. Results: Fifty-eight patients out of 104 displayed good collateral filling (CS ≥2). Poor CS was associated with more severe strokes according to National Institutes of Health Stroke Scale (NIHSS) at arrival (16 vs. 11, p = 0.005) and at 24 h (15 vs. 3, p < 0.001) after the treatment. Good CS was associated with higher systolic blood pressure (p = 0.03), but not with diastolic blood pressure (p = 0.26), pulse pressure (p = 0.20) or mean arterial pressure (p = 0.07). Good CS was associated with better Alberta Stroke Program Early CT Score (ASPECTS) in 24 h follow-up imaging (p < 0.001) and favorable clinical outcome at three months (mRS ≤2, p < 0.001). Median CS was the highest (CS = 3) when systolic blood pressure was between 170 and 190 mm Hg (p = 0.03). There was no significant difference in the number of patients with good (n = 11) and poor (n = 12) CS who received intravenous antihypertensive medication (p = 0.39) before or during the thrombolytic therapy. In multivariate analysis age (p = 0.02, OR 0.957 per year, 95% CI 0.92-0.99), time from the onset of symptoms to treatment (p = 0.005, OR 1.03 per minute, 95% CI 1.01-1.05), distal clot location (p = 0.02, OR 3.52, 95% CI 1.19-10.35) and systolic blood pressure (p = 0.04, OR 1.03 per unit mm Hg, 95% CI 1.00-1.05) predicted good CS. Higher systolic blood pressure (p = 0.049, OR 0.96 per unit mm Hg, 95% CI 0.93-1.00) and pulse pressure (p = 0.005, OR 0.94 per unit mm Hg, 95% CI 0.90-0.98) predicted unfavorable clinical outcome at three months in multivariate analysis. Conclusion: Moderately elevated systolic blood pressure is associated with good collateral circulation in patients treated with intravenous thrombolytic therapy. However, there is an inverse association of systolic blood pressure with the three-month clinical outcome. Diastolic blood pressure, mean arterial pressure and pulse pressure are not statistically and significantly associated with collateral status.

Collateral Circulation Predicts the Size of the Infarct Core and the Proportion of Salvageable Penumbra in Hyperacute Ischemic Stroke Patients Treated with Intravenous Thrombolysis

“…In our study, systolic blood pressure did not reach statistical significance in predicting good CS in contrast to the results of our previous report where moderately elevated systolic blood pressure was associated with good CS [26] . This discrepancy may be due to a smaller sample size.…”

Blood Pressure May Be Associated with Arterial Collateralization in Anterior Circulation Ischemic Stroke before Acute Reperfusion Therapy

“…Previous studies demonstrated inconclusive findings concerning the relationship between arterial blood pressure and collateral circulation [7,8,22]. Lima et al [7], Calleja et al [6], and Liebeskind et al [8] did not show significant association between blood pressure, collateral circulation and clinical outcome.…”

“…Lima et al [7], Calleja et al [6], and Liebeskind et al [8] did not show significant association between blood pressure, collateral circulation and clinical outcome. Rusanen et al [22] found favorable collateral circulation was associated with moderately elevated SBP, especially in the 170-190 mm Hg range, but not reaching statistical significance. On the other hand, induce hypertension therapy has been mentioned with potential benefit on cerebral perfusion [23] and antihypertension treatment possibly linked to higher mortality [24].…”

“…The potential explanations behind these differences involve different baseline characteristics and collateral scales. Comparing with Rusanen et al’s [22] research which included 104 patients, we had an over doubled sample size with a higher average age (74 yr vs. 68.7 yr), larger proportion of diabetes (26.7% vs. 16%) and higher NIHSS (16 vs. 14) on baseline. On the other hand, unlike our study, Rusanen et al’s result based on Souza’s25 collateral grading scale relying on CTA was limited by the shortage of the imaging technology.…”

Different levels of blood pressure, different benefit from dual antiplatelet therapy in minor stroke or TIA patients

“…The precise underlying mechanism remains unclear. Because baseline BP was measured within 24 hours after stroke onset, we considered that the protection mechanism 8–10 of stress-induced hypertension after stroke may amplify the efficacy of dual antiplatelet therapy, especially for those with large artery stenosis in cerebral or carotid arteries. Previous studies 11, 12 indicated that dual antiplatelet therapy with clopidogrel and aspirin was more effective than aspirin alone in reducing microembolic signals in patients with ischemic stroke or TIA due to extracranial or intracranial arterial stenosis.…”