Microembolus Detection by Transcranial Doppler Ultrasound Monitoring (P07.037)

Abstract

Objective: To evaluate the presence of Microembolic Signals (MES) in stroke and transient ischemic attacks, using Transcranial Doppler ultrasound monitoring. Background TCD is a sensitive technique for real time detection of MES which are characterized by unidirectional, high intensity, short duration, random occurrence, and a whistling sound. MES have been detected in carotid artery stenosis, aortic arch plaques, atrial fibrillation, myocardial infarction, prosthetic heart valves, patent foramen ovale, valvular stenosis, during invasive procedures (angiography, percutaneous transluminal angioplasty) and surgery (carotid and cardiopulmonary bypass). Design/Methods: Prospective, observational cross sectional study from Chennai, India of 3200 consecutive stroke or Transient Ischemic Attacks and acute stroke patients seen from 2000 till 2010 at Chennai. Bilateral TCD monitoring were done by insonation of Temporal windows, using the Mark II head frame and Power M Mode TCD machine (PMD100, Spencer Technologies, USA) to detect MES. TCD findings were correlated with magnetic resonance imaging and Angiography (MRI/MRA), computed tomography angiography (CTA), and digital subtraction angiography (DSA). Results: MES was detected in 35 % of patients with symptomatic and in 12.8 % with asymptomatic carotid stenosis. The absolute annual risk of ipsilateral stroke or transient ischaemic attack from baseline and 3 years was 12 % and 6.24 % in patients with and without symptomatic carotid stenosis. 38.4% had MES during carotid endarterectomy and 44 % during carotid angioplasty and stenting. During Sonothrombolysis, MES at the site of arterial obstruction were seen in 22 % and was associated with good outcome (modified Rankin Scale of less than 2). Intracranial stenosis with MES were detected in 22.6 %. Conclusions: Detection of MES by transcranial Doppler, indicates patients with increased risk of stroke. The prence of MES during sonothrombolysis is an indicator of good outcome. A high frequency of MES is observed during Carotid revascularization procedures and intracranil arterial stenosis. Disclosure: Dr. Sivakumar has nothing to disclose. Dr. Sivakumar has nothing to disclose.