Prevalence and Time Course of Microembolic Signals in Patients With Acute Stroke

Abstract

Microemboli are a frequent phenomenon in patients with acute stroke arising from a variety of causes, both in the very early stages and several days after the onset of symptoms. The prevalence of MES decreases significantly over time. MES occur more frequently in patients with carotid artery disease than in patients with a potential cardiac source of embolism. Ipsilateral MES are frequent in patients with carotid artery disease, whereas bilateral MES are suggestive of a cardioembolic origin. Anticoagulation treatment appears to decrease the prevalence of MES, but microemboli still occur in patients receiving intravenous therapy with heparin. Because MES occur intermittently, TCD examinations should be repeated several times, even in patients without MES in the first examination, and long-term monitoring equipment is necessary.

Disappearance of an Oscillating Intraluminal Thrombus in the Carotid Artery Demonstrated by Ultrasonography

“…It has been reported that MESare rarely detected in patients with cardioembolic stroke as compared to those with carotid artery disease (5), and that bilateral MESare suggestive of a cardioembolic origin (6). The MESin the present case indicated that the microemboli originated from the thrombus lodged at the carotid bifurcation rather than from the heart, because the MESwere detected unilaterally from the right MCA distal to the thrombus and no intracardiac thrombi were evident on transesophageal echocardiography.…”

Cerebral Microembolism Is Blocked by Tirofiban, a Selective Nonpeptide Platelet Glycoprotein IIb/IIIa Receptor Antagonist

“…The fact that after cessation of tirofiban infusion the MES rate in some patients did not fully return to the initial rate is in line with previous observations suggesting that the MES rate in patients with carotid artery disease is not constant but declines over time. 18 Since tirofiban is not expected to reduce embolization of atherosclerotic lipid and other matrix constituents, these factors virtually do not contribute to MES in our patients. Therefore, our results provide strong evidence that microemboli from atherothrombotic origin are solid, with platelet-fibrinogen units as predominant constituent parts.…”

A study of microemboli monitoring of atherosclerotic thrombotic cerebral infarction and artery stenosis

“…These authors found that 43% of the patients were again detected as microemboluspositive one week later, and the total frequency of microembolus-positive patients in one week was 7%, which is close to our conclusion. Studies have shown that the ratio of microemboluspositivity peaks immediately after stroke, and the ratio decreases as time goes on (Sliwka et al, 1997;Iguchi et al, 2007;Hao et al, 2010).…”