Acute endovascular stroke therapy

Autopsy findings after intracranial thrombectomy for acute ischemic stroke: a clinicopathologic study of 5 patients

BACKGROUND AND PURPOSE

Endovascular thrombectomy is an increasingly used treatment for arterial occlusion in acute stroke. Various devices (including most extensively the Mechanical Embolus Removal in Cerebral Ischemia [MERCI] Retriever device) have been used for this.

METHODS

We review the neuropathologic findings in 5 patients (age range, 59 to 87 years) who died acutely or as late as 38 days after procedures using the MERCI (4 patients) and Penumbra (1 patient) devices were carried out to remove thromboemboli from the middle cerebral artery. Partial recanalization was achieved by thrombectomy in all 5 patients.

RESULTS

All patients showed extensive cerebral infarcts, 3 of 5 with clinical hemorrhagic transformations of the infarct or frank intraparenchymal hemorrhage after thrombectomy; in 1 case, this was judged to be at least partly on the basis of concomitant hypertensive microvascular disease. With 1 exception, basal arteries examined in detail by immunohistochemistry showed prominent, although usually nonocclusive (and generally nonulcerated), atheromata, often with significant luminal stenosis. One patient showed a subintimal dissection with resultant occlusion of the middle cerebral artery.

CONCLUSIONS

In this highly selected group of patients, the vascular pathological abnormalities affecting basal arteries were variable, but complicated atherosclerosis was a common finding. Extensive irreversible brain necrosis before therapeutic procedures may have contributed to deaths.

Endovascular treatment of an acute left middle cerebral artery >6 h post stroke in a patient presenting with dysphasia and dense right hemiplegia

This paper describes the case of a 32-year-old man presenting with dense right hemiplegia and global aphasia caused by an acute left middle cerebral artery infarct that underwent successful endovascular therapy after being determined ineligible for intravenous tissue plasminogen activator. Clot transversion and balloon disruption followed by intra-arterial Alteplase resulted in successful re-canalization of his middle cerebral artery at 7 h 30 min. At 3 months post stroke, the patient had moderately severe expressive dysphasia but was mobilizing independently with normal right upper and lower limb strength. In conclusion, the 3 month outcome suggests that the therapeutic time window for endovascular therapy might exceed 6 h post stroke.

Occlusion length is a crucial determinant of efficiency and complication rate in thrombectomy for acute ischemic stroke

BACKGROUND AND PURPOSE

Although mechanical thrombectomy (MT) has an encouragingly high recanalization rate in treating stroke, it is associated with severe complications of which the underlying factors have yet to be identified. Because MT is a mechanical approach, the mechanical properties of the thrombus might be crucial for its success. The present study assesses the effect of thrombus length on the in vivo effectiveness and complication rate of MT.

MATERIALS AND METHODS

Angiography and embolization of 21 cranial vessels with radiopaque whole-blood thrombi 10, 20, and 40 mm in length (7 occlusions each) were performed in 7 swine. MT was carried out using a distal snarelike device (BCR Roadsaver) with proximal balloon occlusion. A total of 61 retrievals were attempted.

RESULTS

In the group of 10-mm occlusions, 77.8% of the attempts achieved complete recanalisation. For longer occlusions, the success rates decreased significantly to 20% of attempts for 20-mm occlusions (odds ratio [OR], 14; 95% confidence interval [CI], 2.2-89.2) and 11.1% for 40-mm occlusions (OR, 28; 95% CI, 3.9-202.2; P < .005). The low success rates were largely due to complications associated with thrombus compaction during retrieval. Similarly, the rate of thromboembolic events increased from 0% in 10-mm occlusions to 14.8% in 40-mm occlusions.

CONCLUSIONS

MT using a distal device proved to be a fast, effective, and safe procedure for recanalizing short (10-mm) occlusions in the animal model. However, occlusion length emerged as a crucial determinant for MT with a significant decrease in recanalization success per attempt and increased complication rates. These findings suggest limitations of MT in the clinical application.