Good outcome associated with blood-brain barrier disruption and lower blood pressure after endovascular therapy

Hyperemia detection on arterial spin labeling is associated with final infarct volume in stroke post-endovascular therapy

BACKGROUND AND PURPOSE

Patients with acute ischemic stroke (AIS) treated with endovascular therapy (EVT) may develop hyperemia due to loss of relative cerebral blood flow (rCBF) autoregulation. Hyperemia can be detected on two types of MRI perfusion weighted imaging: dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL). The aim of this study was to compare hyperemia on ASL-rCBF to DSC-rCBF post-EVT and explore the association between hyperemia and final infarct volume (FIV).

METHODS

This is a retrospective analysis of the GUARDS cohort in the ongoing prospective Natural History of Stroke study (ClinicalTrials.gov Identifier: NCT00009243). Patients with AIS who met the following criteria were eligible for this analysis: (i) ≥ 18 years, (ii) no contraindication to 3T MRI, (iii) large vessel occlusion in the anterior circulation, (iv) attempted EVT, and (v) 3T MRI obtained at 24 hours, including DSC-rCBF and ASL-rCBF, and at 5 days post-EVT. Qualitative imaging analysis for hyperemia detection was performed by consensus between two independent raters. Quantitative imaging analysis assessed hyperemic tissue volume, FIV, and Dice coefficients between hyperemia and FIV masks.

RESULTS

Forty patients with median (IQR) age of 70 (62-81) years and admission NIHSS 16 (10-21) were included. Hyperemia was identified on ASL-rCBF in 40 % (16) of patients and on DSC-rCBF in 30 % (12). For 9 patients with hyperemia on both modalities, the ASL-rCBF and DSC-rCBF median volumes were 85.7 (19.4-144.9) and 58.1 (26.2-74.0) (p = 0.10). The Dice coefficient for hyperemia on ASL-rCBF and FIV was higher compared to DSC-rCBF, 0.60 (0.54-0.69) versus 0.39 (0.34-0.49).

CONCLUSION

Hyperemia volumes measured on ASL-rCBF, compared to DSC-rCBF, at 24 hours were more associated with FIV at 5 days. Hyperemia may be an indicator of impaired cerebral autoregulation and potential target for adjunctive therapy to mitigate infarct growth.

Procedural blood pressure and contrast extravasation on dual energy computed tomography after endovascular stroke treatment

BACKGROUND

Blood brain barrier disruption (BBBD) can be visualized by contrast extravasation (CE) after endovascular treatment (EVT) in patients with acute ischemic stroke. Elevated blood pressure is a risk factor for BBBD. However, the association between procedural blood pressure and CE post-EVT is unknown.

METHODS

In this single-center retrospective study, we analyzed 501 eligible patients who received a dual energy CT (DECT) immediately post-EVT for acute ischemic stroke. Procedural blood pressure values (SBPmean, SBPmax, SBPmax-min, and MAPmean) were collected. CE was quantified by measuring the maximum parenchymal iodine concentration on DECT iodine overlay map reconstructions. As a measure for the extent of BBBD, we created CE-ASPECTS by deducting one point per hyperdense ASPECTS region on iodine overlay maps. The association between blood pressure and CE was assessed using multivariable linear regression.

RESULTS

The procedural SBPmean, SBPmax, and MAPmean were 150 ± 26 mmHg, 173 ± 29 mmHg, and 101 ± 17 mmHg, respectively. The median maximum iodine concentration on post-EVT DECT was 1.2 mg/ml (IQR 0.7-2.0), and median CE-ASPECTS was 8 (IQR 5-11). The maximum iodine concentration was not associated with blood pressure. SBPmean, SBPmax, and MAPmean were significantly associated with CE-ASPECTS (per 10 mmHg, β = -0.2, 95 % CI -0.31 to -0.09, β = -0.15, 95 % CI -0.25 to -0.06, β = -0.33, 95 % CI -0.49 to -0.17, respectively).

CONCLUSION

In acute ischemic stroke patients undergoing EVT, particularly in patients achieving successful recanalization, SBPmean, SBPmax, and MAPmean are associated with the extent of BBBD on immediate post-EVT DECT, but not with maximum iodine concentration.

MR Imaging Techniques for Acute Ischemic Stroke and Delayed Cerebral Ischemia Following Subarachnoid Hemorrhage

Acute ischemic stroke (AIS) is a leading cause of death and disability worldwide, and its prevalence is expected to increase with global population aging and the burgeoning obesity epidemic. Clinical care for AIS has evolved during the past 3 decades, and it comprises of 3 major tenants: (1) timely recanalization of occluded vessels with intravenous thrombolysis or endovascular thrombectomy, (2) prompt initiation of antithrombotic agents to prevent stroke recurrences, and (3) poststroke supportive care and rehabilitation. In this article, we summarize commonly used MR sequences for AIS and DCI and highlight their clinical applications.

Deviation From Personalized Blood Pressure Targets Correlates With Worse Outcome After Successful Recanalization

BACKGROUND

Personalized blood pressure (BP) management for patients with acute ischemic stroke after successful endovascular thrombectomy lacks evidence. We aimed to investigate whether the deviation of BP from cerebral autoregulation limits is associated with worse outcomes.

METHODS AND RESULTS

We determined autoregulation by measuring mean velocity index and calculated the percentage of time and the burden (defined as the time-BP area) with BP outside the autoregulatory limits of each subject within 48 hours after endovascular thrombectomy. In total, 91 patients with large vessel occlusion stroke who had achieved successful recanalization were prospectively enrolled between May 2020 and February 2022. The burden with BP outside the autoregulatory limits was associated with poor outcome (modified Rankin Scale score 3-6) at 90 days (adjusted odds ratio, 1.28 [95% CI, 1.03-1.59]). The percentage of time with BP out of the autoregulatory limits was correlated with early neurological deterioration (National Institute of Health Stroke Scale scores increased ≥2 at 7 days) (adjusted odds ratio, 1.38 [95% CI, 1.04-1.83]). The burden of BP that decreased below the autoregulatory lower limit was associated with significant infarct growth (volume of infarct growth >11.6 mL) at 7 days (adjusted odds ratio, 1.21 [95% CI, 1.01-1.44]). The percentage of time that BP exceeded the autoregulatory upper limit was associated with symptomatic intracranial hemorrhage within 48 hours (adjusted odds ratio, 1.55 [95% CI, 1.02-2.34]).

CONCLUSIONS

Both the percentage of time and the burden of BP that deviates from the autoregulation-preserved range are associated with unfavorable clinical outcomes. This study highlights the potential benefits of autoregulation-guided BP management strategy after successful recanalization.