Global hyperperfusion after successful endovascular thrombectomy is linked to worse outcome in acute ischemic stroke

Abstract

Patients with stroke may develop hyperperfusion after a successful endovascular thrombectomy (EVT). However, the relationship between post-EVT hyperperfusion and clinical outcomes remains unclear and requires further clarification. We reviewed consecutive patients with anterior circulation occlusion who were successfully recanalized with EVT. Based on post-EVT arterial spin-labeling images, hyperperfusion was categorized as follows: global hyperperfusion (GHP), increased cerebral blood flow (CBF) in ≥ 50% of the culprit vessel territory; focal hyperperfusion (FHP), increased CBF in < 50% of the culprit vessel territory; no hyperperfusion (NHP), no discernible CBF increase. Factors associated with hyperperfusion were assessed, and clinical outcomes were compared among patients under different hyperperfusion categories. Among 131 patients, 25 and 40 patients developed GHP and FHP, respectively. Compared to other groups, the GHP group had worse National Institutes of Health Stroke Scale score (GHP vs. NHP/FHP, 18.1 ± 7.4 vs. 12.3 ± 6.0; p < 0.001), a larger post-EVT infarct volume (98.9 [42.3-132.7] vs. 13.5 [5.0-34.1] mL; p < 0.001), and a worse 90-day outcome (modified Rankin Scale, 3 [1-4] vs. 2 [0-3]; p = 0.030). GHP was independently associated with infarct volume (B = 0.532, standard error = 0.163, p = 0.001), and infarct volume was a major mediator of the association of GHP with unfavorable outcomes (total effect: β = 0.176, p = 0.034; direct effect: β = 0.045, p = 0.64; indirect effect: β = 0.132, p = 0.017). Patients presenting with post-EVT GHP had poorer neurological prognosis, which is likely mediated by a large infarct volume.

Figure 1

Representative ASL perfusion images of patients with GHP and FHP after a successful EVT. (a) Post-EVT ASL perfusion images obtained after successful recanalization of the left distal internal carotid artery occlusion in a 57-year-old man with GHP. (b) Post-EVT ASL perfusion images obtained after successful recanalization of the left middle cerebral artery M1 segment occlusion in a 72-year-old man with FHP. White arrows indicate areas of hyperperfusion. The color bar on the left side indicates the estimated cerebral blood flow. ASL arterial spin-labeling, EVT endovascular treatment, FHP focal hyperperfusion, GHP global hyperperfusion.

Figure 2

Flowchart of the patient inclusion and exclusion. AIS acute ischemic stroke, ASL arterial spin-labeling, EVT endovascular treatment, mRS modified Rankin Scale.

Figure 3

Distribution of modified Rankin Scale at 90 days according to the degree of post-EVT hyperperfusion. EVT endovascular treatment, FHP focal hyperperfusion, GHP global hyperperfusion, NHP no hyperperfusion.

Figure 4

Mediating role of infarct volume on the effect of global hyperperfusion on worse 90-day mRS. Unstandardized and standardized regression coefficients for each path of the mediation model are presented. The 95% bootstrap confidence intervals for the unstandardized coefficients are provided. ^†Controlled for age, sex, smoking, initial NIHSS score, occlusion site of M2, intravenous thrombolysis, and hemorrhagic transformation. ^‡Controlled for age, sex, hypertension, active cancer, initial diastolic blood pressure, initial NIHSS score, stroke etiology, intravenous thrombolysis, and hemorrhagic transformation. ***p < 0.001; **p < 0.01; *p < 0.05. B unstandardized coefficient, β standardized coefficient, mRS modified Rankin Scale, NIHSS National Institutes of Health Stroke Scale.