Isolated Middle Cerebral Artery Stenoses: A Serial Follow-up Study using Transcranial Doppler Ultrasonography
Background: Whereas the natural history of extracranial arterial disease is well known, the course of intracranial vascular lesions has not been well investigated. We prospectively evaluated the prognosis and long-term course of isolated middle cerebral artery (MCA) stenosis by using transcranial Doppler ultrasonography (TCD).
Methods: Forty-seven MCA stenoses in 32 patients were assessed at entry by TCD, MR angiography and/ or conventional angiography. We excluded patients with potential cardiac embolic source. We also excluded patients who had atherosclerotic lesions in the other intracranial arteries and proximal internal carotid arteries to select isolated MCA stenosis. Fifteen patients had bilateral MCA stenoses and 12 had only asymptomatic MCA lesions. All patients were treated with antiplatelet agents (n=26) or anticoagulants (n=6). Follow-up TCD was done at 3 to 12 month intervals.
Results: The mean duration of follow-up was 29.7 months (3-70 months). During follow-up, new cerebral ischemic events developed in only 2 patients with initially symptomatic stenosis. Progression and regression on follow-up TCD were found more often in symptomatic lesions than in asymptomatic ones (12/20 vs. 5/27, p<0.01). Progression was observed more often in patients with bilateral stenoses than those with unilateral lesions (4/15 vs. 0/17, p<0.05). Focal short segmental stenoses on angiographies showed more regression than diffuse long segmental lesions (11/13 vs. 2/34, p<0.001).
Conclusions: These findings suggest that isolated MCA stenoses are dynamic lesions. Symptomatic stenosis seems to be relatively unstable with a higher frequency of progression and regression than asymptomatic one. Regression of stenosis in some cases may be due to partial lysis of lodged emboli.
Jae Guk Kim, Hanna Choi, Do-Hyung Kim, Sung-Yeon Sohn and Soo Joo Lee
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