EVT Shows Benefit in Large Vessel Occlusion Stroke Despite Late Presentation

Beom Joon Kim, PhD

Results from a case-control study suggest that patients with anterior circulation large vessel occlusion (LVO) presenting very late (>16 hours to 10 days) from their last well known (LKW) time may still benefit from endovascular treatment, despite previous notions of the therapy only being effective during a window less than 16 to 24 hours from LKW.

Of the included 150 patients who had an acute ischemic stroke (AIS) with internal carotid artery or middle cerebral occlusion and arrived 16 hours or more from time LKW, 24 (16%) received EVT. A modified Rankin Scale (mRS) score of 0 to 2 at 3 months after score occurred in 55 patients (37%)—13 of 24 patients who received EVT (54%) and 42 of 126 patients who received medical treatment (33%).

EVT was associated with better odds of a 90-day mRS of 0 to 2 (adjusted odds ratio [OR], 11.08; 95% CI, 1.88—108.60) as were the odds of having a favorable 90-day mRS score shift (common adjusted OR, 5.17; 95% CI, 1.80–15.62).

Additional results of the study, which was led by Beom Joon Kim, PhD, stroke neurologist, Seoul National University Bundang Hospital, showed that EVT was associated with a favorable mRS shift (common adjusted OR, 10.54; 95% CI, 2.18—59.34) among a subgroup of 109 patients who were 24 hours from time LKW.

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“Patients with acute ischemic stroke and anterior circulation LVO may harbor substantial salvageable tissues in the very late period from 16 to 24 hours after the time LKW,” Kim and colleagues noted. “Endovascular treatment in this population increased the chance of being independent after stroke, and the benefit remained constant over the inclusion period, but with a nonsignificant increase in hemorrhages. However, this was a small observational study.”

Type 2 parenchymal hemorrhage was seen in 7 participants (5%), including 3 of the 24 (13%) patients in the EVT subgroup and 4 of the 126 patients (3%) in the medical treatment subgroup (adjusted OR, 4.06; 95% CI, 0.63—26.30). Symptomatic hemorrhage with an increased in the National Institute of Health Stroke Scale (NIHSS) score of 4 points or more occurred in 2 patients, both of whom received EVT.

Multivariable logistic regression models with propensity score (PS) matching also showed significant associations for having an mRS score of 0 to 2 (adjusted OR, 7.89; 95% CI, 2.25—32.42) or a favorable shift in mRS score (common adjusted OR, 5.91; 95% CI, 2.42–14.77) after adjustment for relevant covariates.

Additional post-hoc analysis measured the final infarcts in 138 patients (92%) using magnetic resonance imaging (125 patients) or CT scan (13 patients), at a median of 93 hours (interquartile range [IQR], 66—120 hours) after arrival. In total, 40 patients who had follow-up imaging performed had a smaller final infarct volume than the baseline ischemic core (6 of 24 [25%] in the EVT subgroup and 34 of 114 patients [30%] in the best medical management group; P = .82). Kim and colleagues noted that the final infarct volume was not different from the baseline ischemic core according to the treatment subgroup, but patients who received EVT showed a tendency toward a higher proportion of reperfused penumbra.

Baseline characteristics of those included in the study showed a mean age at onset of 70.1 (standard deviation [SD], 13.0) years, with 81 male patients (54%), a median NIHSS score of 12 (IQR, 8—18) and a median duration between the time LKW to onset time of 43.5 hours (IQR, 22.8–76.9). Additionally, the median penumbra volume (>6 seconds) was 55.0 mL (IQR, 15–128 mL), and the median mismatch ratio was 4.0 (IQR, 0.9–18.3).

REFERENCE

Kim BJ, Menon BK, Kim JY, et al. Endovascular treatment after stroke due to large vessel occlusion for patients presenting very late from time last known well. JAMA Neurol. Published August 10, 2020. doi: 10.1001/jamaneurol.2020.2804