Occlusion Site, Thrombus Length Are Good Predictors of ENDi in Minor Stroke, LVO

Pierre Seners, MD, PhD

Data from a recent study suggest that an easily accessible score based on occlusion site and thrombus length can reliably predict early neurological deterioration of ischemic origin (ENDi) in patients with minor stroke and large vessel occlusion (LVO).

A 4-point score derived from occlusion site and thrombus length showed good discrimination for ENDi (C statistic = 0.76; 95% CI, 0.70-0.82) which was validated in an additional cohort (C statistic = 0.78; 95% CI, 0.70-0.86). Scores of 0, 1, 2, and 3 corresponded to ENDi probabilities of approximately 3%, 7%, 20%, and 35%, respectively.

“Two independent predictors of ENDi emerged from the present study. The first was more proximal occlusion site, in line with... earlier studies in patients with minor stroke not treated with intravenous thrombolysis (IVT) and patients with nonminor stroke treated with IVT. The second independent predictor of ENDi was thrombus length, such that the longer the thrombus, the higher the odds of ENDi,” first author Pierre Seners, MD, PhD, neurology department, GHU Paris psychiatrie et neurosciences, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, and colleagues wrote. “To our knowledge, this is the first study to report such an association.” 

Seners and colleagues analyzed data from the MINOR-STROKE collaboration that collected data from 45 French stroke centers between 2006 and 2018 and formed 2 cohorts. The derivation cohort consisted of 729 patients with a mean age of 70 years (standard deviation [SD], 15), 335 (46.0%) of which were men. The validation cohort consisted of 347 patients with a mean age of 69 years (SD, 15), 190 (54.8%) of which were men. 

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Patients in the derivation cohort had a median National Institutes of Health Stroke Scale (NIHSS) score of 3 (interquartile range [IQR], 1-4). Occlusion sites were the internal carotid artery in 97 patients (13.3%), M1 in 207 (28.4%), M2 in 395 (54.2%), and the basilar artery in 30 (40.1%). ENDi occurred in 88 patients (12.1%; 95% CI, 9.7-14.4). 

Patients that experienced ENDi had a median NIHSS score increase of 8 (IQR, 5-14). ENDi occurred within 2 hours of IVT start in 42 patients (48%), between 2 to 6 hours after in 11 (13%), 6 to 12 hours in 7 (8%), and 12 to 24 hours in 28 (32%). Rescue mechanical thrombectomy (MT) was performed in 49 (56%) patients with ENDi, with groin puncture occurring at a median delay of 95 (IQR, 70-150) minutes following ENDi and successful reperfusion (mTICI grade of 2b to 3) obtained in 40 patients (82%).

Excellent functional outcome (defined as modified Rankin scale [mRS] score less than 2) was achieved in 28 patients (34%) with ENDi and 466 patients (77.5%) without ENDi (P <.001). With rescue mT, 22 (48%) of patients achieved excellent functional outcome and 6 (16%) achieved this without rescue MT. Twenty-two patients (48%) with ENDi and rescue MT achieved excellent functional outcome as compared to 466 (77.5%) without ENDi (P <.001).

Overall, ENDi was strongly associated with poorer 3-month outcomes (common odds ratio [OR], 7.37; 95% CI, 4.79-11.35; P <.001) in patients with and without MT, although patients with MT were more likely to have better functional outcomes than those without (common OR, 3.72; 95% CI, 1.67-8.32; P = .001). 

Through multivariate analysis, researchers determined that a more proximal occlusion site and a longer thrombus were independently associated with ENDi. They derived a 4-point score from these variables, assigning 1 point for thrombus length and 3 points for occlusion site. The C statistic of the score was 0.76 (95% CI, 0.70-0.82) and the ENDi score showed good discrimination (C statistic = 0.78; 95% CI, 0.70-0.86) and calibration (Hosmer-Lemeshow test P = .78) in predicting ENDi in the external validation cohort.

“Our study documents a substantial rate of ENDi in patients with minor stroke and LVO treated with IVT, fueling the current debate on whether bridging therapy should be carried out in this population. Second, we demonstrate that the odds of post-IVT ENDi are strongly determined by occlusion site and thrombus length. Lastly, the straightforward score derived from these associations and successfully validated in an independent cohort affords good discriminative power for ENDi prediction, which may eventually help clinicians for decision-making,” Seners and colleagues concluded.

REFERENCE

Seners P, Hassen WB, Lapergue B, et al. Prediction of early neurological deterioration in individuals with minor stroke and large vessel occlusion intended for intravenous thrombolysis alone. JAMA Neurol. Published online January 11, 2021. doi:10.1001/jamaneurol.2020.4557