Isolated anterior cerebral artery territory infarction: dissection as an etiological mechanism.

BACKGROUND

Intracranial arterial lesions are important causes of ischemic stroke, particularly in the Asian population. Of the intracranial lesions, the etiology of isolated anterior cerebral artery (ACA) territory infarction is not fully elucidated. The purpose of this study was to determine the etiological and clinical characteristics of patients with isolated ACA territory infarction, especially those with ACA dissection.

METHODS

Of 3,115 consecutive patients with acute ischemic stroke, 42 patients (1.3%, 30 men, 38-88 years old) having an isolated ACA territory infarction were studied. Infarcts were principally verified by diffusion-weighted MRI, and vascular lesions were identified by MRA, CTA, or digital subtraction angiography. Three-dimensional rotational angiography was performed if needed.

RESULTS

Eighteen patients (43%) were diagnosed as having ACA dissection. The stroke subtypes of the other 24 patients included cardioembolism for 6 patients and large-artery atherosclerosis for 8. Patients with dissection were younger (p < 0.001) and heavier (p = 0.026), less commonly had heart disease (p = 0.002) and previous stroke (p = 0.002), and had lower initial systolic blood pressure (p = 0.029) and lower levels of D-dimer (p = 0.041) than patients without dissection. Stroke onset more commonly followed physical exertion (p = 0.013) and headache (p = 0.041) in patients with dissection than in patients without dissection. At hospital discharge, the modified Rankin scale score was lower in patients with dissection than in patients without dissection (p = 0.005).

CONCLUSIONS

Arterial dissection was the most common vascular lesion underlying an isolated ACA territory infarction in our Japanese cohort. Patients with ACA dissection had unique baseline characteristics and unique conditions at stroke onset.