Benefit of thrombectomy after ischemic cerebral infarction.

As recent empirical data show, patients with occlusions of a large artery in the anterior cerebral circulation, if they have large core volumes, benefit from additional endovascular stroke therapy in which the clot is mechanically removed. The studies, published simultaneously in The New England Journal of Medicine, thus confirm the current guideline recommendations.

After an ischemic stroke, blood flow to the affected area of the brain must be restored within a few hours so that those affected suffer as little consequential damage as possible. This can be done either by drug thrombus dissolution or by vascular catheter intervention with removal of the thrombus (interventional thrombectomy) [1]. Stents are used in this process. These catheters are advanced so that they come to rest behind the thrombus. Then the mesh is unfolded at the site of the thrombus, trapping the clot inside. The catheter is then moved back and the thrombus is thus removed from the vessel in its entirety (stent retriever).

Thrombectomy after occlusion of the internal carotid ar tery or the middle cerebral artery

The international SELECT-2 trial [2] prospectively and randomly investigated in an open-label design the benefit of thrombectomy within 24 hours of symptom onset in severe ischemic cerebral infarcts, in patients with occlusion of the Internal carotid artery (internal carotid artery) or of the first segment of the Arteria cerebri media (A. cerebri media) With large ischemic core volume (3 to 5 on the Alberta Stroke Program Early Computed Tomography score or a core volume of at least 50 ml on perfusion CT or diffusion MRI). The primary endpoint was the degree of disability on the modified Rankin scale (Table 1) after 90 days. 178 patients received thrombectomy in addition to drug therapy, and 174 received drug therapy alone. There was a highly significant superiority of the additional intervention with a 51% higher chance of a better outcome (odds ratio [OR]: 1.51, p<0.001). However, 34 patients in the thrombectomy group experienced complications, including vascular perforation, dissection, or vasospasm. However, the feared intracranial hemorrhages occurred in only one person treated with thrombectomy and in two persons in the comparison group.

Intervention after occlusion of the anterior carotid artery

A very similar result was shown in a large Chinese study [3]. There, 456 patients with occlusions of the anterior cerebral artery with large ischemic core volume (3 to 5 on the Alberta Stroke Program Early Computed Tomography score or a core volume of at least 70-100 ml) had been included. 231 received thrombectomy, and 225 were treated with medication. 285 of the study participants (both groups) received thrombolysis. This study was also terminated early because of the highly significant superiority of thrombectomy. As in the SELECT-2 trial, the primary end point included the difference in outcome, assessed with the modified Rankin scale. After 90 days, the OR was 1.37 (p=0.004). However, intracranial hemorrhages occurred more frequently in the thrombectomy group than in the drug-only group in this study (symptomatic intracranial hemorrhages 14 vs. 6, hemorrhages in general 113 vs. 39).

Endovascular stroke therapy
Endovascular therapy has revolutionized the treatment of severe strokes. Treatment can significantly improve neurological symptoms (paralysis, speech impairment). This significantly reduces the likelihood of severe disability or death following a major stroke. In mechanical thrombectomy, a catheter is inserted through the inguinal artery directly to the vessel occlusion. For the reopening itself, various techniques can be used. In aspiration, negative pressure is applied to directly aspirate the blood clot. Nowadays, stent-like instruments (stent retrievers) are frequently used (in addition), with which the blood clot can be quickly and completely removed from the vessel in almost all cases. General anesthesia is not mandatory for the procedure; sedation of the patient is usually sufficient. Rarely, procedural complications may occur (cerebral hemorrhage, strokes to other regions of the brain). Thrombectomy is not appropriate in patients who reach the hospital 24 h after stroke or even later.

to [5,6]

Conclusion

The SELECT2 study supports the standard of care set forth in the German Society of Neurology (DGN) guideline [4], which states that endovascular therapy should be performed when a large artery in the anterior circulation is occluded. The recommendation that mechanical thrombectomy may also be beneficial in cases of occlusion of the anterior cerebral ar tery or posterior cerebral artery is based on expert consensus. “The Chinese study now provides data that this recommendation is correct and that we should also thrombectomize these infarcts with large core areas,” Prof. Berlit summarized.

Literature:

“Two randomized trials support evidence for thrombectomy for occlusion of large intracranial arteries,” German Society of Neurology (DGN), Feb. 20, 2023.
Sarraj A, et al: SELECT2 Investigators. Trial of Endovascular Thrombectomy for Large Ischemic Strokes. N Engl J Med 2023; 388(14): 1259-1271.
Huo X, et al: ANGEL-ASPECT Investigators. Trial of Endovascular Therapy for Acute Ischemic Stroke with Large Infarct. N Engl J Med 2023; 388(14): 1272-1283.
Ringleb P, et al: Acute therapy of ischemic stroke, S2e guideline (as of 11/9/2022), AWMF registry number 030/046 2022, www.dgn.org/leitlinien,(last accessed 04/23/2023).
“Endovascular Stroke Therapy (Mechanical Thrombectomy,” www.klinikum.uni-heidelberg.de/verfahren/endovaskulaere-schlaganfalltherapie-mechanische-thrombektomie-211635,(last accessed 04/23/2023).
“Mechanical Thrombectomy and Thrombolysis for Stroke,” www.usz.ch/fachbereich/neuroradiologie/angebot/mechanische-
thrombectomy-and-thrombolysis-for-stroke, (last accessed 04/23/2023).
Eckstein HH, et al: Surgical and endovascular therapy of extracranial carotid stenoses. Secondary data analysis of statutory quality assurance data from 2009 to 2014. Dtsch Arztebl Int 2017; 114: 729-736.