MRI profile and response to endovascular reperfusion after stroke (DEFUSE 2): a prospective cohort study

Abstract

Background It is uncertain if endovascular stroke therapy leads to improved clinical outcomes due to a paucity of data from randomized placebo-controlled trials. The aim of this study was to determine if MRI can be used to identify patients who are most likely to benefit from endovascular reperfusion. Methods Consecutive patients, scheduled to undergo endovascular therapy within 12 hours of stroke onset, were enrolled in a multi-center prospective cohort study. Aided by an automated image analysis software program, investigators interpreted the baseline MRI. They determined, prior to endovascular treatment, if the patient had an MRI profile (Target Mismatch) that suggested salvageable tissue was present. Reperfusion was assessed on an early follow-up MRI and defined as a >50% reduction in the volume of the baseline perfusion lesion. A favorable clinical response was defined as a ≥8 point improvement on the NIH Stroke Scale (NIHSS) between baseline and day 30 or an NIHSS score of 0–1 at 30 days. Findings Following endovascular therapy reperfusion occurred in 46 of 78 (59%) Target Mismatch patients and in 12 of 21 (57%) No Target Mismatch patients. The adjusted odds ratio for favorable clinical response associated with reperfusion was 8·5 (95% CI 2·6 – 28) in the Target Mismatch group and 0·2 (95% CI 0·0 – 1·6) in the No Target Mismatch group (p=0·003 for difference between odds ratios). Reperfusion was associated with an increased odds of good functional outcome at 90 days (OR is 5.2, 95% CI 1.4–19) and attenuation of infarct growth at 5 days (30 ml of median growth with reperfusion vs. 73 ml without reperfusion, p=0·01) in the Target Mismatch group but not in patients without Target Mismatch. Interpretation Target Mismatch patients who achieved early reperfusion following endovascular stroke therapy had more favorable clinical outcomes and less infarct growth. No association between reperfusion and favorable outcomes was present in patients without Target Mismatch. These data support a randomized controlled trial of endovascular treatment in patients with the Target Mismatch profile.

CTA Collateral Status and Response to Recanalization in Patients with Acute Ischemic Stroke

“…18 In our study, patients with poor collateral status who did not recanalize had more infarct growth than did patients with poor collateral status who recanalized. Our results do not support the reperfusion injury hypothesis.…”

“…Similar to previous studies supporting the use of a "mismatch"-based para- digm on perfusion imaging, our study provides evidence for the use of a "CTA collateral assessment-based paradigm" in selecting patients for IAT. 18 We did not have data on every procedural time metric; approximately 30% of follow-up clinical data (mRS at 90 days) was ascertained by telephone. We were also underpowered to do a secondary analysis on the effect of time to recanalization on clinical outcomes stratified by collateral status.…”

“…Collateral status by use of the rLMC score (0 -20) was trichotomized into 3 groups: good (17)(18)(19)(20), intermediate (11)(12)(13)(14)(15)(16), and poor (0 -10), according to previously published literature. 3 Differences between these 3 groups were assessed by means of the Fisher exact test for proportions, 1-way ANOVA for parametric data, and a rank sum test for nonparametric data.…”

MRI before Intraarterial Therapy in Ischemic Stroke: Feasibility, Impact, and Safety

“…11 Furthermore, a recent study has suggested the value of perfusion imaging (PI) for selecting patients for IAT. 12 Despite the promise of MRI, there are few data concerning IAT outcomes after MRI-based selection. In most centers, patients are selected for intraveneous tPA and IAT on the basis of a CT scan.…”

Performance and Predictive Value of a User-Independent Platform for CT Perfusion Analysis: Threshold-Derived Automated Systems Outperform Examiner-Driven Approaches in Outcome Prediction of Acute Ischemic Stroke

“…Appropriate patient selection may thus prove paramount, and identification of a subpopulation most likely to benefit has been the subject of extensive inquiry. 1,2 While the precise profile of this target population remains to be conclusively defined, recent work has highlighted the potential strengths of stratification by using the ischemic penumbra formalism defining an irreversibly injured infarct core and putative penumbra of at-risk tissues. 1,3 Despite promising results, penumbral imaging has met with skepticism and inconsistent outcomes, particularly because the broad array of imaging and computational approaches and interpretive parameters has precluded formulation of generalizable conclusions.…”