Residual Hypoperfusion Despite Successful Recanalization In Patients With Large Artery Occlusion Stroke: The Prevalence And Risk Factors

Background Prompt and effective recanalization of the occluded artery to revise cerebral hypoperfusion status and rescue the dying ischemic penumbra is the key therapy for acute large artery occlusion stroke.However,successful recanalization may not always promise ideal reperfusion of the affected tissues according to clinical and animal trials,which might contribute to that some patients with successful recanalization still survive severe disability or even death.Till now,the prevalence and related risk factors of residual hypoperfusion despite recanalization in real world is unclear.Methods We employed a retrospective analysis based on a prospective stroke registry of a single center and enrolled the patients with anterior large artery occlusion stroke who received stent retriever thrombectomy and acquired successful recanalization.All participants undertook multimodal magnetic resonance imaging examination before and at 24 hours after thrombectomy.hypoperfusion area was calculated as Tmax >6s region on perfusion sequence.“residual hypoperfusion”(RH)was defined as the proportion of the hypoperfusion area at 24 hours accounting for more than 10% of the baseline,and more than 50%as the “severe residual hypoperfusion”(s RH).We explored the prevalence of RH and s RH,and compared the clinical outcomes and related risk factors including age,sex,medical history,laboratory test,blood pressure,stroke severity and recanalization duration between patients of RH/s RH and respective controls.Binary Logistic regression was used to study the independent risk factors of RH and s RH.Results A total of 78 patients were enrolled into the final analysis,of whom the average age was 69.5±11.8 years old and 65.4% were male.The median of baseline NIHSS score was 14(interquartile range 9-19),the baseline systolic blood pressure was 152.4±20.4mm Hg,and the onset to recanalization duration was 340 minutes(interquartile range 285-436 minutes).After thrombectomy,55.1% and 44.9% patients acquired complete recanalization [modified Thrombolysis In Cerebral Infarction(m TICI)score 3] and major partial recanalization(m TICI 2b).Of these patients,42.3% presented RH,while 17.9%had s RH.Compared with the control group,patients of RH had fewer good outcome(modified Rankin scale 0-2)at 3 months(36.4% vs.62.2%,p=0.038)and higher intracranial hemorrhage transformation(24.2% vs.6.7%,p=0.046).Logistic regression showed that RH(odds ratios,0.30;95% confidence interval,0.10-0.84;p=0.022)and s RH(odds ratios,0.21;95% confidence interval,0.05-0.83;p=0.026)were both associated with clinical outcome after adjusting for age,sex and baseline NIHSS score,and s RH was also related to intracranial hemorrhage(odds ratio,4.46;95% confidence interval 1.05-18.94;p=0.043).Regarding risk factors,patients of RH had higher systolic blood pressure(159.5±22.5mm Hg vs.147.3±17.1mm Hg,p=0.008)than controls,while patients of s RH showed higher systolic blood pressure(164.5±21.0mm Hg vs.149.8±19.4mm Hg,p=0.013)and higher proportion of major partial recanalization(71.4% vs.39.1%,p=0.038).After adjusting for other confounders,systolic blood pressure before recanalization was associated with RH(odds ratio,1.03;95%confidence interval,1.00-1.06;p=0.030),and systolic blood pressure(odds ratio,1.05;95% confidence interval,1.01-1.09;p=0.028)and major partial recanalization(odds ratio,4.35;95% confidence interval,1.06-17.88;p=0.042)were associated with s RH.Conclusions Residual hypoperfusion,despite successful recanalization of upstream vessels,exists in part of patients with acute large artery occlusion stroke,and is associated with poor outcomes.Systolic blood pressure and major partial recanalization status may be the independent risk factors.