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Blood viscosity may affect the mechanisms of stroke and early neurological deterioration (END). We aimed to investigate the relationship between blood viscosity, stroke mechanisms, and END in patients with middle cerebral artery (MCA) infarction. Patients with symptomatic MCA atherosclerosis (≥ 50% stenosis) were recruited. Blood viscosity was compared across patients with different mechanisms of symptomatic MCA disease: in situ thrombo-occlusion (sMCA-IST), artery-to-artery embolism (sMCA-AAE), and local branch occlusion (sMCA-LBO). END was defined as four points increase in the National Institutes of Health Stroke Scale score from baseline during the first week. The association between blood viscosity and END was also evaluated. A total of 360 patients (76 with sMCA-IST, 216 with sMCA-AAE, and 68 with sMCA-LBO) were investigated. Blood viscosity was highest in patients with sMCA-IST, followed by sMCA-AAE and sMCA-LBO (P < 0.001). Blood viscosity was associated with END in patients with MCA disease. Low shear viscosity was associated with END in patients with sMCA- LBO (adjusted odds ratio, aOR 1.524; 95% confidence interval, CI 1.035–2.246), sMCA- IST (aOR 1.365; 95% CI 1.013–1.839), and sMCA- AAE (aOR 1.285; 95% CI 1.010–1.634). Blood viscosity was related to END in patients with stroke caused by MCA disease. [ABSTRACT FROM AUTHOR]

Two different stroke mechanisms are involved in small vessel disease: branch atheromatous disease (BAD) and lipohyalinotic degeneration (LD). We compared mechanisms of stroke in lenticulostriate arteries (LSA) vs. anterior pontine arteries (APA) and verified factors associated with stroke mechanisms, including shape of middle cerebral artery (MCA) and basilar artery (BA). We retrospectively reviewed patients with acute ischemic stroke with penetrating artery territory confirmed by MRI. The mechanisms of stroke were categorized based on diffusion-weighted imaging; BAD was defined as lesion larger than 10 mm in LSA and lesions involving basal pontine in APA. Other lesions were classified as LD. The shapes of MCA and BA were classified as straight, with one angle, or with two angles (U, C or S shape, respectively) using anterior–posterior view. The study included 221 patients. LD was more common in LSA infarcts, but BAD was more common in APA infarcts (p < 0.001). Low initial National Institutes of Health Stroke Scale [Adjusted Odds ratio (aOR) = 0.78; p < 0.001], absence of hyperlipidemia [aOR = 0.31; p = 0.002], previous statin use [aOR = 4.35; p = 0.028] LSA infarcts [reference = APA territory; aOR = 11.07; p < 0.001], and S-shaped vessels (reference = straight shaped vessels; aOR = 3.51; p = 0.004) were independently associated with LD. Angulations in the mother vessels may be more associated with true small vessel disease more with LD than BAD. [ABSTRACT FROM AUTHOR]

Background: Clinical and radiological characteristics of middle cerebral artery (MCA) infarction may differ according to the location of occlusion. Objectives: We investigated the difference between proximal and distal symptomatic MCA occlusion (MCAO) in patients with ischemic stroke. The factors associated with the imaging characteristics were also analyzed. Methods: Patients with ischemic stroke due to MCAO were consecutively enrolled. The location of MCAO was determined by the ratio of the length of the ipsilesional MCA to that of the contralateral MCA and dichotomized to proximal and distal MCAO. Clinical and radiological characteristics were compared between patients with proximal and distal MCAO. Factors associated with the basal ganglia (BG) involvement, hemorrhagic transformation (HT), and neurological change during admission were investigated. Results: Among 181 included patients, MCAO location showed a bimodal peak (at the proximal [n = 99] and distal MCA [n = 82]). Proximal MCAO was more frequently associated with hyperlipidemia and large artery atherosclerosis, whereas distal MCAO was more frequently associated with hypertension, atrial fibrillation, and cardioembolic stroke. BG involvement was similar between the 2 groups (48 vs. 39%; p = 0.21), whereas HT was more frequent in distal MCAO (10 vs. 23%; p = 0.02). Among patients with proximal MCAO, hyperintense vessel sign was less frequently observed in those with a BG involvement than those without (38 vs. 60%; p = 0.03). Among those without BG involvement, the presence of HT was very low and similar between patients with proximal and distal MCAOs (1.9 vs. 2.0%). However, in patients with BG involvement, HT was more frequently observed in those with distal MCAO than in those with proximal MCAO (54.8 vs. 15.7%; p < 0.001). The presence of hyperintense vessel sign (OR 0.172, 95% CI 0.051–0.586; p = 0.005) and distal MCAO (OR 0.200, 95% CI 0.059–0.683; p = 0.011) was independently associated with improvement during admission. Conclusion: Proximal MCAO is more frequently associated with atherosclerosis, whereas distal MCAO is more frequently associated with cardioembolism. In proximal MCAO, the status of collateral flow presented by hyperintense vessel sign may affect the involvement of BG. In distal MCAO, distal migration of the embolus, which first impacted at the proximal MCA causing BG ischemia, may explain the high rate of HT by reperfusion injury. Hyperintense vessel sign and distal MCAO were independently associated with neurological improvement during admission. [ABSTRACT FROM AUTHOR]