Erythrocyte-Rich Thrombus Is Associated with Reduced Number of Maneuvers and Procedure Time in Patients with Acute Ischemic Stroke Undergoing Mechanical Thrombectomy.

BACKGROUND: Only few studies have investigated the relationship between the histopathology of retrieved thrombi and clinical outcomes. This study aimed to evaluate thrombus composition and its association with clinical, laboratory, and neurointerventional findings in patients treated by mechanical thrombectomy due to acute large vessel occlusion. METHODS: At our institution, 79 patients were treated by mechanical thrombectomy using a stent retriever and/or aspiration catheter between August 2015 and August 2016. The retrieved thrombi were quantitatively analyzed to quantify red blood cells, white blood cells, and fibrin by area. We divided the patients into two groups - a fibrin-rich group and an erythrocyte-rich group - based on the predominant composition in the thrombus. The groups were compared for imaging, clinical, and neurointerventional data. RESULTS: The retrieved thrombi from 43 patients with acute stroke from internal carotid artery, middle cerebral artery, or basilar artery occlusion were histologically analyzed. Erythrocyte-rich thrombi were present in 18 cases, while fibrin-rich thrombi were present in 25 cases. A cardioembolic etiology was significantly more prevalent among the patients with fibrin-rich thrombi than among those with erythrocyte-rich thrombi. Attenuation of thrombus density as shown on computed tomography images was greater in patients with erythrocyte-rich thrombi than in those with fibrin-rich thrombi. All other clinical and laboratory characteristics remained the same. Patients with erythrocyte-rich thrombi had a smaller number of recanalization maneuvers, shorter procedure times, a shorter time interval between arrival and recanalization, and a higher percentage of stent retrievers in the final recanalization procedure. The occluded vessels did not differ significantly. CONCLUSIONS: In this study, erythrocyte-rich thrombus was associated with noncardioembolic etiology, higher thrombus density, and reduced procedure time.

Positional Occlusion of Vertebral Artery Due to Cervical Spondylosis as Rare Cause of Wake-up Stroke: Report of Two Cases.

BACKGROUND: Positional compression of the vertebral artery (VA) owing to cervical spondylosis is an uncommon cause of stroke. We report two cases of cervical spondylosis causing wake-up stroke, which is extremely rare. CASE DESCRIPTION: The first patient was a 78-year-old woman with vertigo and vomiting lasting from waking up. Magnetic resonance imaging (MRI) and angiography documented right cerebellar infarction, and stenosis of the right cervical VA. Dynamic angiography revealed that the right VA was occluded when her neck was extended or rotated to the right. Computed tomography (CT) angiography revealed the right VA compression by the right C5 superior articular process osteophytes. The second patient was a 77-year-old man with dysarthria from waking up. MRI and angiography revealed right cerebellar infarction associated with the right VA stenosis and the left VA occlusion at C5-C6, whose cause was diagnosed as compression caused by bilateral uncovertebral osteophytes on CT angiography. Dynamic angiography showed that neck rotation to the right aggravated the right VA stenosis while recanalizing the left VA. Both patients were treated with a free radical scavenger (edaravone) and heparin, and underwent surgical decompression of VAs 14 or 18 days after onset. No recurrent ischemic events occurred thereafter. CONCLUSIONS: Magnetic resonance angiography of extracranial cervical VAs may be useful as an initial screening test for VA compression secondary to cervical spondylosis as a rare cause of wake-up stroke, especially in cases of cerebral infarction in the posterior circulation with no evidences of causative arrhythmia and intracranial lesions.