Stroke Alert: A Review of Current Clinical Stroke Literature
By Matthew E. Fink, MD, Professor and Chairman, Department of Neurology, Weill Cornell Medical College, and Neurologist-in-Chief, New York Presbyterian Hospital
A Simple Score Can Predict Outcome after Ischemic Stroke
Source: O'Donnell MJ, et al, for the Investigators of the Registry of the Canadian Stroke Network. The PLAN Score: A bedside prediction rule for death and severe disability following acute ischemic stroke. Arch Intern Med 2012;1-9. doi:10.1001/archinternmed.2013.30.
The investigators analyzed data from 9847 patients (4943 in the derivation cohort and 4904 in the validation cohort) hospitalized with acute ischemic stroke and included in the Registry of the Canadian Stroke Network from 2003 to 2008. Overall 30-day mortality was 11.5% in the derivation cohort and 13.5% in the validation cohort. In a multivariate model, nine clinical variables were identified as preadmission comorbidities and given a score (preadmission dependence = 1.5, cancer = 1.5, congestive heart failure = 1, atrial fibrillation = 1); reduced level of consciousness was given a score = 5, age was given 1 point/decade, and neurological deficit was scored as significant weakness of the leg = 2, significant weakness of the arm = 2, aphasia or neglect = 1. The maximum score was 25.
The PLAN score (preadmission comorbidities, level of consciousness, age, and neurologic deficit) identified patients who will have a poor outcome after hospitalization for acute ischemic stroke. In the validation cohort, the PLAN score predicted 30-day mortality (C statistic, 0.87), death or severe dependence at discharge (0.88), and 1-year mortality (0.84). The PLAN score also predicted good outcome (modified Rankin, 0-2) at discharge (C statistic, 0.80).
Mismatch Between Perfusion and Diffusion on MRI Can Identify Good Candidates for Endovascular Reperfusion Therapy
Source: Lansberg MG, et al, for the DEFUSE 2 study investigators. MRI profile and response to endovascular reperfusion after stroke (DEFUSE 2): A prospective study. Lancet Neurology 2012;11:860-867.
There is a paucity of data from randomized, place-bo-controlled trials of endovascular therapy (ET) in ischemic stroke resulting in uncertainty regarding its efficacy. In a prospective cohort study, the DEFUSE investigators, at eight centers in the United States and one in Austria, consecutively enrolled 138 patients scheduled to have ET within 12 hours of ischemic stroke onset. A baseline MRI was performed within 90 minutes of the endovascular procedure and included diffusion and perfusion measurements using a standardized quantitative imaging analysis program, and patients were divided into those who had a diffusion/perfusion mismatch and those who did not have a mismatch. Reperfusion was assessed with a repeat MRI 12 hours after ET, and reperfusion was defined as a 50% reduction in the perfusion volume compared to baseline. The primary outcome measure was favorable clinical response, defined as improvement in the NIH Stroke Scale of ≥ 8. Secondary outcome was good functional outcome as assessed by the modified Rankin scale score of ≤ 2 at day 90.
Of the total group, 99 had all imaging and clinical data and could be fully evaluated according to the protocol. Reperfusion was successful in 46 of 78 (59%) with target mismatch and in 12 of 21 (57%) patients without target mismatch. The odds ratio (OR) for favorable clinical response to reperfusion was 8.8 (95% confidence interval [CI], 2.7-29.0) in the target mismatch group and 0.2 (0.0-1.6) in the no target mismatch group (P = 0.003). Reperfusion was associated with good functional outcome at 90 days (OR, 4.0; 95% CI, 1.3-12.2) in the target mismatch group, but not in the no target mismatch group. The study results strongly support the hypothesis that diffusion/perfusion target mismatch on MRI predicts a more favorable clinical outcome in patients with ischemic stroke who undergo endovascular reperfusion therapy.
Cerebral Microbleeds May Be Associated with Elevated Vascular Endothelial Growth Factor
Source: Dassam P, et al. Association of cerebral microbleeds in acute ischemic stroke with high serum levels of vascular endothelial growth factor. Arch Neurol 2012;69:1186-1189.
Cerebral microbleeds are found in about 30% of patients with acute ischemic infarcts, often in areas remote from the region of infarction. Histologically, they are found adjacent to small vessels affected by hypertension or amyloid angiopathy. One mechanism for their formation could be a more widespread microangiopathy with leakage of the blood-brain barrier, and vascular endothelial growth factor (VEGF) has been implicated in such a mechanism. The authors measured serum VEGF within 24 hours of acute ischemic stroke in 20 patients. The median levels of VEGF in the entire group of stroke patients was significantly higher than in a non-stroke control group. Five of the 20 ischemic patients had cerebral microbleeds on MRI, and median VEGF level in those patients was significantly higher than in the group without cerebral microbleeds (P = 0.003). This study raises several issues regarding the possible role of VEGF in the genesis of intracerebral hemorrhage, both spontaneous and in the setting of thrombolytic therapies.