NEUROLOGY (Alert)
Stroke Alert
By Matthew E. Fink, MD
Selwaness M, et al. Atheroscerotic plaque in the left carotid artery is more vulnerable than in the right. Stroke 2014;45:3226-3230.
Ischemic stroke in the distribution of the carotid arteries has been reported to occur more often in the left carotid distribution than the right, but it is unclear if this is due to the higher sensitivity of diagnosis, due to language dysfunction in the left-sided lesions, or if they are truly more common. Many right hemisphere strokes, if they are small, could be missed because of the subtlety of the clinical presentation. The authors investigated the plaque prevalence, severity, and composition of atherosclerotic lesions in the carotid arteries, and compared the left and the right.
Carotid MRI scanning was performed in 1414 stroke-free participants, older than the age of 45 years, to assess the morphology of any atherosclerotic plaques, specifically to look at the presence of a lipid core, intraplaque hemorrhage, calcification, or fibrous tissue in each carotid artery. Differences between the left and right sides were tested using paired t-tests and a generalized estimating equation analysis. The majority of participants (85%) had bilateral carotid plaques. When unilateral plaques were identified, they were more prevalent on the left side than the right side (67% vs 33%; P < 0.001). Plaque thickness was greater on the left, but degree of stenosis did not differ between right and left. Intraplaque hemorrhage was more prevalent on the left compared to the right, whereas calcification occurred more often on the right.
Carotid plaque size and composition are not symmetrically distributed, and there may be more vulnerable plaques that develop in the left internal carotid compared to the right. These observations may explain the difference in prevalence between right and left internal carotid artery distribution ischemic strokes.
Katsanos A, et.al. Recurrent stroke and patent foramen ovale: A systematic review and meta-analysis. Stroke 2014;45:3352-3359.
Patent foramen ovale (PFO) is common in both the general population, as well as in patients with cryptogenic stroke, with an estimated prevalence somewhere between 15-35%. Recurrent neurovascular events, both recurrent ischemic stroke as well as transient ischemic attacks, are frequent in these patients but it is not clear whether patients with PFOs have an increased rate of recurrent events compared to those patients who do not have PFOs. Katsanos and colleagues performed a review and meta-analysis of all available prospective studies that reported recurrent cerebrovascular events in patients who were diagnosed with cryptogenic stroke or transient ischemic attacks, and were treated medically. These were then compared to the control ischemic stroke patients who did not have PFOs. Fourteen eligible studies were identified with a total of 4251 patients. Patients with stroke and PFO did not have a higher risk of recurrent stroke/transient ischemic attacks (risk ratio, 1.18; 95% confidence interval, 0.78-1.79; P = 0.03). The authors also compared the size of the PFO with the risk of recurrent events and did not find any association.
Based on the available evidence, there does not appear to be an increased risk of recurrent cerebral ischemic events in patients with PFO compared to those without a PFO.
