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
Significant Heritable Component to Risk and Size of Intracerebral Hematoma
Source: Devan WJ, et al, on behalf of the International Stroke Genetics Consortium. Heritability estimates identify a substantial genetic contribution to risk and outcomes of intracerebral hemorrhage. Stroke 2013;44:1578-1583.
In an international study of intracerebral hematoma (ICH), investigators from North America and Europe collected clinical information, imaging data, and blood samples to perform DNA extraction and genotyping with specific studies on apolipoprotein E (APOE) haplotypes. This information was analyzed using the GCTA 1.0 software package to estimate the degree of heritability based on disease traits. Heritability was assessed for three different outcomes – ICH risk, hematoma volume, and 90-day mortality.
A total of 791 ICH cases and 876 controls were eligible for inclusion. Of these, 366 cases presented with deep ICH and 338 had lobar ICH. There was a separate analysis of heritability for APOE genotypes vs the rest of the genome. Overall, ICH heritability was estimated at 29% for non-APOE loci and at 15% for APOE. Heritability for 90-day mortality was 41.5% for non-APOE loci and 10% for APOE. Heritability for hematoma volume was substantial and estimated at 60% for non-APOE loci and 12% for APOE. The role of APOE genotypes was much less than expected based on previous small studies, and this study indicates that there are other important genetic loci that play an important role and that are yet to be identified.
Spontaneous Dissections of the Vertebral Arteries and the Carotid Arteries have Different Clinical Presentations and Outcomes
Source: von Babo M, et al. Differences and similarities between spontaneous dissections of the internal carotid artery and the vertebral artery. Stroke 2013;44:1537-1542.
The authors compared potential risk factors, clinical symptoms, diagnostic delay, and 3-month outcome between spontaneous internal carotid artery dissection (sICAD) and spontaneous vertebral artery dissection (sVAD). There were 668 patients with sICAD and 302 patients with sVAD from three university hospitals. Patients with sICAD were older (43.3 vs 42.0, P < 0.001), more often men (62.7% vs 53%, P = 0.004), and presented more often with tinnitus (10.9% vs 3.4%, P < 0.001), and they had more severe ischemic strokes (NIHSS 10 vs 5, P < 0.001). Patients with sVAD more often had bilateral dissections (15.2% vs 7.6%, P < 0.001) and were more often smokers (36% vs 28%, P = 0.007). Thunderclap headache (9.2 % vs 3.6%, P = 0.001) and neck pain were more common (65.5% vs 33.5%, P < 0.001) in sVAD. Time to diagnosis was similar in both groups and improved between 2001 and 2012 compared to the previous 10-year period. In sVAD, favorable outcome 3 months after ischemic stroke (mRS, 0-2: 88.8% vs 58.4%, P < 0.001), recurrent transient ischemic attack (4.8% vs 1.1%, P = 0.001), and recurrent ischemic stroke (2.8% vs 0.7%, P = 0.02) within 3 months were more frequent. The clinical presentations of these dissections are quite different and suggest different etiologies for the disorders.