Different types of percutaneous endovascular treatments for acute ischemic stroke

Which type of endovascular treatment is best in terms of safety and effectiveness for people with acute ischemic stroke (AIS)?

Stroke is one of the most common causes of death and disability today. Different endovascular (inside the blood vessel) treatments (also called thrombectomy) aim to remove the blood clot causing AIS to restore blood flow and reverse the stroke symptoms. Thrombo-aspiration involves sucking the clot away using a fine catheter tube. Stent-retriever thrombectomy grabs and retrieves the clot from the blocked blood vessel. An aspiration-retriever combined technique has also been shown to be an effective way to remove blood clot. However, it is unclear which type of thrombectomy is best in AIS treatment.

Date of search
We completed the search for studies on 16 May 2022.

Study characteristics
We combined data from two randomized controlled trials (a type of study where participants are randomly assigned to one of two or more treatment groups) with a total of 651 participants who had AIS due to large vessel occlusion confirmed by imaging, such as computed tomographic angiography (CTA) and digital subtraction angiography (DSA). These trials took place in multiple centers and compared thrombo-aspiration with stent-retrieval thrombectomy. Another two studies compared the combined technique with thrombo-aspiration and stent-retriever thrombectomy alone.

Key results
There was no clear difference in safety and effectiveness of the two approaches (thrombo-aspiration and stent-retrieval thrombectomy) in the management of AIS patients.

Quality of the evidence
The quality of evidence in the review was high, although the doctors and participants knew which treatment was being given, which could have led to bias.

Authors' conclusions: 

This review did not establish any difference in safety and effectiveness between the thrombo-aspiration approach and stent-retrieval thrombectomy for treating people with AIS. Furthermore, the combined group did not show any obvious advantage over either intervention applied alone.

Read the full abstract...

Acute ischemic stroke (AIS) is the abrupt reduction of blood flow to a certain area of the brain which causes neurologic dysfunction. Different types of percutaneous arterial endovascular interventions have been developed, but as yet there is no consensus on the optimal therapy for people with AIS.


To compare the safety and efficacy of different types of percutaneous arterial endovascular interventions for treating people with AIS.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 4 of 12, 2022), MEDLINE Ovid (1946 to 13 May 2022), Embase (1947 to 15 May 2022), Science Citation Index Web of Science (1900 to 15 May 2022), Scopus (1960 to 15 May 2022), and China Biological Medicine Database (CBM; 1978 to 16 May 2022). We also searched the ClinicalTrials.gov trials register and the World Health Organization (WHO) International Clinical Trials Registry Platform to 16 May 2022.

Selection criteria: 

Randomized controlled trials (RCTs) comparing one percutaneous arterial endovascular intervention with another in treating adult patients who have a clinical diagnosis of AIS due to large vessel occlusion and confirmed by imaging evidence, including thrombo-aspiration, stent-retrieval thrombectomy, aspiration-retriever combined technique, and thrombus mechanical fragmentation.

Data collection and analysis: 

Two review authors independently performed the literature searches, identified eligible trials, and extracted data. A third review author participated in discussions to reach consensus decisions when any disputes occurred. We assessed risk of bias and applied the GRADE approach to evaluate the quality of the evidence. The primary outcome was rate of modified Rankin Scale (mRS) of 0 to 2 at three months. Secondary outcomes included the rate of modified Thrombolysis In Cerebral Infarction (mTICI) of 2b to 3 postprocedure, all-cause mortality within three months, rate of intracranial hemorrhage on imaging at 24 hours, rate of symptomatic intracranial hemorrhage at 24 hours, and rate of procedure-related adverse events within three months.

Main results: 

Four RCTs were eligible. The current meta-analysis included two trials with 651 participants comparing thrombo-aspiration with stent-retrieval thrombectomy. We judged the quality of evidence to be high in both trials according to Cochrane's risk of bias tool RoB 2.

There were no significant differences between thrombo-aspiration and stent-retrieval thrombectomy in rate of mRS of 0 to 2 at three months (risk ratio [RR] 0.97, 95% confidence interval [CI] 0.82 to 1.13; P = 0.68; 633 participants; 2 RCTs); rate of mTICI of 2b to 3 postprocedure (RR 1.01, 95% CI 0.95 to 1.07; P = 0.77; 650 participants; 2 RCTs); all-cause mortality within three months (RR 1.01, 95% CI 0.74 to 1.37; P = 0.95; 633 participants; 2 RCTs); rate of intracranial hemorrhage on imaging at 24 hours (RR 1.03, 95% CI 0.86 to 1.24; P = 0.73; 645 participants; 2 RCTs); rate of symptomatic intracranial hemorrhage at 24 hours (RR 0.90, 95% CI 0.49 to 1.68; P = 0.75; 645 participants; 2 RCTs); and rate of procedure-related adverse events within three months (RR 0.98, 95% CI 0.68 to 1.41; P = 0.90; 651 participants; 2 RCTs).

Another two included studies reported no differences for the comparisons of combined therapy versus stent-retrieval thrombectomy or thrombo-aspiration. One RCT is ongoing.