Stroke Alert: A Review of Current Clinical Stroke Literature
By Matthew E. Fink, MD, Interim Chair and Neurologist-in-Chief, Director, Division of Stroke & Critical Care Neurology, Weill Cornell Medical College and New York Presbyterian Hospital
How Frequently is Atrial Fibrillation Detected in Patients with Stroke or TIA?
Source: Alhadramy O, et. al. Prevalence and predictors of paroxysmal atrial fibrillation on Holter monitor in patients with stroke or transient ischemic attack. Stroke 2010; 41:2596-2600.
Cardiologists at the university of alberta reviewed the records of 1,128 consecutive patients at the stroke clinic and identified 426 with a definite TIA or stroke. They reviewed clinical data and cardiac and brain imaging and performed a logistic regression analysis to determine the predictors of atrial fibrillation as identified on a 24-hour Holter monitor. Overall, 413 of the 426 patients underwent Holter monitoring, and paroxysmal atrial fibrillation (PAF) occurred in 39 patients (9.2%), all older than 55 years. The presence of multiple acute or chronic brain infarcts on CT scan (OR = 1.7 for each lesion seen), number of chronic infarcts on MRI (OR = 3.0 for each lesion increase), or any acute cortical infarct on imaging (OR = 5.8) were associated with PAF.
Magnetic Resonance Imaging Can Predict Malignant Middle Cerebral Artery Infarction Within 6 Hours of Symptom Onset
Source: Thomalla G, et. al. Prediction of malignant middle cerebral artery infarction by magnetic resonance imaging within 6 hours of symptom onset: A prospective multicenter observational study. Ann Neurol 2010;68:435-445.
Malignant middle cerebral artery (mca) infarction carries a high mortality (> 70%), but survival is dramatically improved with early hemicraniectomy (Vahedi, Lancet Neurol 2007). In spite of its efficacy, hemicraniectomy is rarely performed and often is delayed until it is too late to benefit the patient. The clinical symptoms and signs of herniation are inconsistent and unpredictable, and opportunities to treat may be missed. A reliable imaging marker would be very helpful to select appropriate surgical candidates at an early time in their course.
Thomella et al prospectively observed 140 patients with acute ischemic stroke and MCA main stem occlusion, and obtained brain MRI, including diffusion-weighted imaging and MR-angiography within 6 hours of symptom onset. Of the 140 patients studied, 27 (19.3%) developed malignant MCA infarction. They found the following parameters to be significant predictors of malignant MCA infarctionlarger DWI lesion volume (per 1 ml odds ratio = 1.04), combined MCA and internal carotid artery occlusion (OR = 5.8), and severity of neurological deficit on admission based on NIHSS (OR per 1 point = 1.1.6). Based on these criteria, close monitoring and repeated imaging should be performed on high-risk patients to identify candidates, early, for hemicraniectomy.
Stroke During Pregnancy Does Not Increase Risk to the Newborn
Source: Kang JH, et. al. Stroke during pregnancy: No increased risk of preterm delivery and low birth weight, a nationwide case-controlled study. J Neurol Neurosurg Psychiatry 2010;81:1211-1214.
In this population-based, case-controlled study from China, 161 women having singleton births who had strokes during their pregnancy were compared to 1,288 mothers matched in age and year of delivery for comparison. Logistic regression analyses were performed to examine the odds of complications to the newborn.
The authors found that mothers with stroke were more likely to have lower family incomes (P = 0.031), gestational hypertension (P = 0.004), anemia (P < 0.001), and pre-eclampsia/eclampsia (P = 0.039) than the non-stroke comparison group. The results also showed that in several measures of newborn health, including prevalence of preterm birth, low birth weight, and small-for-gestational-age babies, there were no differences between mothers who had strokes during pregnancy compared to normal women who did not.