Endovascular Thrombectomy for Mild Strokes: How Low Should We Go?

Abstract

Background and Purpose: Endovascular thrombectomy (EVT) is effective for acute ischemic stroke with large vessel occlusion (LVO) and NIHSS ≥6. However, EVT benefit for mild deficits LVOs (NIHSS<6) is uncertain. We evaluated EVT efficacy and safety in mild strokes with LVO. Methods: A retrospective cohort of patients with anterior circulation LVO and NIHSS<6 presenting within 24hours from last-seen-normal were pooled. Patients were divided into 2 groups: EVT or medical management. 90day mRS=0–1 was the primary outcome; mRS=0–2 was the secondary. Symptomatic intracerebral hemorrhage (sICH) was the safety outcome. Clinical outcomes were compared through a multivariable logistic regression after adjusting for age, presentation NIHSS, time-last-seen-normal-to-presentation, center, IV-alteplase, ASPECTS, and thrombus location. We then performed propensity score matching as a sensitivity analysis. Results were also stratified by thrombus location. Results: 214 patients (EVT-124, medical management-90) were included from 8 US and Spain centers between January/2012 and March/2017. The groups were similar in age, ASPECTS, IV-alteplase rate and time-last-seen-normal-to-presentation. There was no difference in mRS=0–1 between EVT and medical management (55.7% versus 54.4%, respectively, aOR=1.3, 95%CI=0.64–2.64, p=0.47). Similar results were seen for mRS=0–2 (63.3% EVT versus 67.8% medical management, aOR=0.9, 95%CI=0.43–1.88, p=0.77). In a propensity matching analysis, there was no treatment effect in 62 matched pairs (53.5%EVT, 48.4% medical management; OR=1.17, 95%CI=0.54–2.52, p=0.69). There was no statistically significant difference when stratified by any thrombus location; M1 approached significance (p=0.07). sICH rates were higher with thrombectomy (5.8% EVT versus 0% medical management, p=0.02). Conclusions: Our retrospective multicenter cohort study showed no improvement in excellent and independent functional outcomes in mild strokes (NIHSS<6) receiving thrombectomy irrespective of thrombus location, with increased sICH rates, consistent with the guidelines recommending the treatment for NIHSS≥6. There was a signal towards benefit with EVT only in M1 occlusions; however this needs to be further evaluated in future RCTs.

Bridging Therapy or IV Thrombolysis in Minor Stroke with Large Vessel Occlusion

“…Second, occlusion site significantly modified the effect of bridging therapy, namely the latter was associated with better functional outcome in proximal or distal M1 occlusions, and with worse functional outcome and higher odds of any ICH or sICH for M2 occlusions. The present work differs from previous observational studies in several key points, [3][4][5][6][7][8][9][10] precluding direct comparison of the results. First, it is the first to specifically assess the effect of EVT added on IVT-as compared to IVT alone, the currently recommended therapy in patients with disabling minor stroke 1 -in this population, as all the previously published observational studies mixed patients treated with and without IVT, with range of IVT-treated patients varying from 31 to 78%.…”

“…First, it is the first to specifically assess the effect of EVT added on IVT-as compared to IVT alone, the currently recommended therapy in patients with disabling minor stroke 1 -in this population, as all the previously published observational studies mixed patients treated with and without IVT, with range of IVT-treated patients varying from 31 to 78%. [3][4][5][6][7][8][9][10] Second, and most importantly, we elected to assign patients to the treatment group in which they were intended on decision making, at variance with most earlier studies. [5][6][7]9,10 Accordingly, almost 1 in 10 patients in the intended IVT alone group eventually underwent rescue EVT, whereas 1 in 3 patients in the intended bridging group eventually did not receive EVT mainly because of early post-IVT recanalization.…”

“…Several observational studies have compared clinical outcome from EVT added on medical treatment versus medical treatment alone in this population. [3][4][5][6][7][8][9][10] However, an "intention-to-treat" design comparing intended EVT added on medical treatment (ie, including those patients who eventually did not receive EVT, because of, eg, post-IVT early recanalization) to intended medical treatment alone (ie, including those patients who eventually received EVT because of early neurological deterioration) was used in only three of the above studies. 3,4,8 Yet, using the intention-to-treat design is the only way to directly address the equipoise that faces the treating physician at the time of decision making.…”

Reperfusion therapy for minor stroke: A systematic review and meta‐analysis

“…Recently, a multicenter cohort study reported that thrombectomy did not increase the likelihood of excellent functional outcomes in mild strokes (NIHSS < 6) irrespective of thrombus location, with rising symptomatic intracerebral hemorrhage rates in these patients (Sarraj et al, 2018). For minor stroke or TIA, it is difficult to distinguish those patients who have the chance to attain spontaneous recanalization within the time window.…”

“…For minor stroke or TIA, it is difficult to distinguish those patients who have the chance to attain spontaneous recanalization within the time window. Recently, a multicenter cohort study reported that thrombectomy did not increase the likelihood of excellent functional outcomes in mild strokes (NIHSS < 6) irrespective of thrombus location, with rising symptomatic intracerebral hemorrhage rates in these patients (Sarraj et al, 2018).…”