Sishir Mannava, MD

Mohamed GA, Aboul Nour H, Nogueira RG, Mohammaden MH, Haussen DC, Al-Bayati AR, Nguyen TN, AbdalkaderM, Kaliaev A, Ma A, et al. Repeated Mechanical Endovascular Thrombectomy for Recurrent Large Vessel Occlusion: A Multicenter Experience. Stroke. 2021.

In this article, Mohamed et al. report on the outcome of repeat mechanical thrombectomy (rMT) for patients who have recurrent LVO in a multicenter retrospective cohort study involving 6 tertiary institutions in the United States over a period of four years. The study collected patients who had MT via various interventional approaches, (e.g., aspiration catheters, stent retriever devices, stents, angioplasty balloons, or combinations thereof) depending on each participating hospital’s protocols. Out of their large cohort of 3,059 patients who underwent MT, 56 patients (1.8%) had at least one rMT. Fifty patients (93%) had one rMT, three (6%) underwent two rMT procedures, and one (2%) had rMT performed three times. Of these patients, 54 of 56 patients (96%) were analyzed. Of note, the interval between index MT (iMT) and rMT was 2 days, and 35 patients (65%) had recurrent LVO (rLVO) during the index hospitalization.

A final modified Thrombolysis in Cerebral Infarction (mTICI) recanalization score of 2b or 3 was achieved in all 54 patients during iMT (100%) and in 51 of 54 patients (94%) of those patients who underwent rMT, mostly with the combination of stent retrieval and aspiration. Mechanism of stroke in rLVO was cardioembolism in 30 patients (56%), intracranial atherosclerosis in four patients (7%), extracranial atherosclerosis in two patients (4%), and other causes in 18 patients (33%).

The majority, 32 out of 54 patients (59%), of those patients who experienced rLVO had it of a previously treated artery, with most (73%) affected the pre-treated left middle cerebral artery. Median NIHSS at presentation was 14 for index LVO (iLVO) and 16 for rLVO (P=0.96). However, post mechanical thrombectomy NIHSS scores were worse after rMT compared to iMT (median 12 vs. 7, P= 0.008), and worse when rMT was performed during the same hospitalization compared to those with re-occlusion after discharge (median 7 vs 5, P= 0.028).

50 of the 54 patients studied had a discharge modified Rankin score (mRS) documented after rMT and 15 patients (30%) had minimal or no disability (mRS ≤2), 25 patients (50%) had moderate to severe disability (mRS 3-5), and 10 patients (20%) died. The rate of ICH was not substantially different with rMT compared to the iMT. In terms of limitations of the study, the low rate of rLVO requiring rMT and the retrospective nature of this study limit interpretation, and there may have been a selection bias regarding selecting rLVO patients for rMT, which may have provided better outcomes. In addition, the outcome data was only collected at discharge, so long-term outcomes are unknown.

The authors concluded that based on their findings, approximately 2% of patients with MT experience rLVO usually of a previously treated artery during the index hospitalization and rMT appears to be safe and effective for recanalization with good outcome (mRS ≤2) expected in about 30% of patients. The authors also found that cardioembolism and atherosclerotic large vessel disease were the common etiologies associated with re-occlusion after iMT, suggesting that providers should have a higher index of suspicion for rLVO in these populations, and that inadequate anticoagulation or antiplatelet therapy and a cardioembolic source may be risk factors for early rLVO.

Assuming that clinicians are able to better detect these cases of rLVO, which can be challenging to detect in the very early period following iMT, this study has made a significant step in terms of providing how often this occurs and the outcomes possible when rMT route is pursued.