Mild fever as a catalyst for consumption of the ischaemic penumbra despite endovascular reperfusion

COmbination of Targeted temperature management and Thrombectomy after acute Ischemic Stroke (COTTIS): a pilot study

BACKGROUND

To evaluate the feasibility and safety of a fast initiation of cooling to a target temperature of 35°C by means of transnasal cooling in patients with anterior circulation large vessel occlusion (LVO) undergoing endovascular thrombectomy (EVT).

METHODS

Patients with an LVO onset of <24 hour who had an indication for EVT were included in the study. Transnasal cooling (RhinoChill) was initiated immediately after the patient was intubated for EVT and continued until an oesophageal target temperature of 35°C was reached. Hypothermia was maintained with surface cooling for 6-hour postrecanalisation, followed by active rewarming (+0.2°C/hour). The primary outcome was defined as the time required to reach 35°C, while secondary outcomes comprised clinical, radiological and safety parameters.

RESULTS

Twenty-two patients (median age, 77 years) were included in the study (14 received additional thrombolysis, 4 additional stenting of the proximal internal carotid artery). The median time intervals were 309 min for last-seen-normal-to-groin, 58 min for door-to-cooling-initiation, 65 min for door-to-groin and 123 min for door-to-recanalisation. The target temperature of 35°C was reached within 30 min (range 13-78 min), corresponding to a cooling rate of 2.6 °C/hour. On recanalisation, 86% of the patients had a body temperature of ≤35°C. The median National Institutes of Health Stroke Scale at admission was 15 and improved to 2 by day 7, and 68% of patients had a good outcome (modified Rankin Scale 0-2) at 3 months. Postprocedure complications included asymptomatic bradycardia (32%), pneumonia (18%) and asymptomatic haemorrhagic transformation (18%).

CONCLUSION

The combined application of hypothermia and thrombectomy was found to be feasible in sedated and ventilated patents. Adverse events were comparable to those previously described for EVT in the absence of hypothermia. The effect of this procedure will next be evaluated in the randomised COmbination of Targeted temperature management and Thrombectomy after acute Ischemic Stroke-2 trial.

Continued Infarction Growth and Penumbral Consumption After Reperfusion in Vaccine-Naive Patients With COVID-19: A Case-Control Study

BACKGROUND. Neurologic sequelae of SARS-CoV-2 include potentially malignant cerebrovascular events arising from complex hemodynamic, hematologic, and inflammatory processes occurring in concert. OBJECTIVE. This study concerns the hypothesis that despite angiographic reperfusion COVID-19 promotes continued consumption of at-risk tissue volumes after acute ischemic stroke (AIS), yielding critical insights into prognostication and monitoring paradigms in vaccine-naive patients experiencing AIS. METHODS. This retrospective study compared 100 consecutive COVID-19 patients with AIS presenting between March 2020 and April 2021 with a contemporaneous cohort of 282 AIS patients without COVID-19. Reperfusion classes were dichotomized into positive (extended thrombolysis in cerebral ischemia [eTICI] score = 2c-3) and negative (eTICI score < 2c) groups. All patients underwent endovascular therapy after initial CT perfusion imaging (CTP) to document infarction core and total hypoperfusion volumes. RESULTS. Ten COVID-positive (mean age ± SD, 67 ± 12 years; seven men, three women) and 144 COVID-negative patients (mean age, 71 ± 16 years; 76 men, 68 women) undergoing endovascular reperfusion, with antecedent CTP and follow-up imaging, comprised the final dataset. Initial infarction core and total hypoperfusion volumes (mean ± SD) were 1.5 ± 18 mL and 85 ± 100 mL in COVID-negative patients and 30.5 ± 34 mL and 117 ± 80.5 mL in COVID-positive patients, respectively. Final infarction volumes were significantly larger in patients with COVID-19, with median volumes of 77.8 mL versus 18.2 mL among control patients (p = .01), as were normalized measures of infarction growth relative to baseline infarction volume (p = .05). In adjusted logistic parametric regression models, COVID positivity emerged as a significant predictor for continued infarct growth (OR, 5.10 [95% CI, 1.00-25.95]; p = .05). CONCLUSION. These findings support the potentially aggressive clinical course of cerebrovascular events in patients with COVID-19, suggesting greater infarction growth and ongoing consumption of at-risk tissues, even after angiographic reperfusion. CLINICAL IMPACT. SARS-CoV-2 infection may promote continued infarction progression despite angiographic reperfusion in vaccine-naive patients with large-vessel occlusion AIS. The findings carry potential implications for prognostication, treatment selection, and surveillance for infarction growth among revascularized patients in future waves of infection by novel viral strains.

Characterizing Fast and Slow Progressors in Anterior Circulation Large Vessel Occlusion Strokes

BACKGROUND AND PURPOSE

Infarct growth rate (IGR) in acute ischemic stroke is highly variable. We sought to evaluate impact of symptom-reperfusion time on outcomes in patients undergoing mechanical thrombectomy (MT).

METHODS

A prospectively maintained database from January,2012-August,2020 was reviewed. All patients with isolated MCA-M1 occlusion who achieved complete reperfusion(mTICI2C-3), had a witnessed symptom onset and follow-up MRI were included. IGR was calculated as final infarct volume (FIV)(ml)/symptom onset to reperfusion time(hours) and was dichotomized according to the median value into slow-(SP) versus fast-progressors (FP). The primary analysis aimed to evaluate the impact of symptom-reperfusion time on 90-day mRS in SP and FP. Secondary analysis was performed to identify predictors of IGR.

RESULTS

A total of 137 patients were eligible for analysis. Mean age was 63 ± 15.4 years and median IGR was 5.13ml/hour. SP(n = 69) had higher median ASPECTS, lower median rCBF<30% lesion volume, higher proportion of favorable collaterals and hypoperfusion intensity ratio (HIR)<0.4, higher minimal mean arterial blood pressure before reperfusion, and lower rates of general anesthesia compared to FP(n = 68). Symptom-reperfusion time was comparable between both groups. SP had higher rates of 90-day mRS0-2(71.9%vs.38.9%,aOR;7.226,95%CI[2.431-21.482],p < 0.001) and lower median FIV. Symptom-reperfusion time was associated with 90-day mRS0-2 in FP (aOR;0.541,95%CI[0.309-0.946],p = 0.03) but not in SP (aOR;0.874,95%CI[0.742-1.056],p = 0.16). On multivariable analysis, high ASPECTS and favorable collaterals in the NCCT/CTA model, and low rCBF<30% and HIR<0.4 in the CTP model were independent predictors of SP.

CONCLUSIONS

The impact of symptom-reperfusion time on outcomes significantly varies across slow-versus fast-progressors. ASPECTS, collateral score, rCBF<30%, and HIR define stroke progression profile.

Association between hyperpyrexia and poststroke outcomes in patients with recanalization after mechanical thrombectomy: a retrospective cohort study

BACKGROUND

Limited data are available for evaluating the relationship between the prognosis and body temperature (BT) in patients treated with mechanical thrombectomy (MT), especially in those with successful recanalization. We aimed to explore the prognostic value of BT in predicting outcomes of stroke recovery at 3 months poststroke.

METHODS

We retrospectively analyzed the relationship among BT levels as a continuous variable, with fever (BT ≥ 37.5℃) as a binary variable, and obtained several outcomes of interest. Subjects were stratified according to successful recanalization (thrombolysis in cerebral infarction scores of 2b-3) following MT. Functional independence was defined as a modified Rankin scale (mRS) score of 0-2.

RESULTS

In total, 258 patients were included. The proportion of patients with functional independence was significantly lower among patients with BT ≥ 37.5℃ than among those with BT < 37.5 °C (45.3 % versus 23.0 %; P < 0.001). In the multivariate analysis, hyperpyrexia (especially BT ≥ 38 °C) was significantly associated with poor 3-month outcomes in patients treated with MT. Subgroup analysis was conducted by comparing the successful recanalization group with the non-recanalization group, showing that BT ≥ 37.5 °C was associated with a significantly lower proportion of functional independence in the recanalized patients. Besides, the Kaplan-Meier model showed that the fever group had significantly lower survival rates than the non-fever group during the 3-month follow-up.

CONCLUSIONS

In patients treated with MT, hyperpyrexia is an independent predictor of poststroke outcomes at 3 months, particularly in those with successful recanalization.

Penumbra Consumption Rates Based on Time-to-Maximum Delay and Reperfusion Status: A Post Hoc Analysis of the DEFUSE 3 Trial

BACKGROUND AND PURPOSE

In patients with acute large vessel occlusion, the natural history of penumbral tissue based on perfusion time-to-maximum (T_max) delay is not well established in relation to late-window endovascular thrombectomy. In this study, we sought to evaluate penumbra consumption rates for T_max delays in patients with large vessel occlusion evaluated between 6 and 16 hours from last known normal.

METHODS

This is a post hoc analysis of the DEFUSE 3 trial (The Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke), which included patients with an acute ischemic stroke due to anterior circulation occlusion within 6 to 16 hours of last known normal. The primary outcome is percentage penumbra consumption, defined as (24-hour magnetic resonance imaging infarct volume-baseline core infarct volume)/(T_max 6 or 10 s volume-baseline core volume). We stratified the cohort into 4 categories based on treatment modality and Thrombolysis in Cerebral Infarction (TICI score; untreated, TICI 0-2a, TICI 2b, and TICI3) and calculated penumbral consumption rates in each category.

RESULTS

We included 141 patients, among whom 68 were untreated. In the untreated versus TICI 3 patients, a median (interquartile range) of 53.7% (21.2%-87.7%) versus 5.3% (1.1%-14.6%) of penumbral tissue was consumed based on T_max >6 s (P<0.001). In the same comparison for T_max>10 s, we saw a difference of 165.4% (interquartile range, 56.1%-479.8%) versus 25.7% (interquartile range, 3.2%-72.1%; P<0.001). Significant differences were not demonstrated between untreated and TICI 0-2a patients for penumbral consumption based on T_max >6 s (P=0.52) or T_max >10 s (P=0.92).

CONCLUSIONS

Among extended window endovascular thrombectomy patients, T_max >10-s mismatch volume may comprise large volumes of salvageable tissue, whereas nearly half the T_max >6-s mismatch volume may remain viable in untreated patients at 24 hours.