Stroke

Regardless of whether patients undergo mechanical thrombectomy or medical therapy, meeting this metric after treatment is a good sign.

Complete revascularization 24 hours after stroke treatment predicts good outcomes, while any level of recanalization is associated with smaller infarct volume, according to new analysis of data from the REVASCAT trial.

While this link is seen in both arms of the trial, researchers say, it is notable that higher rates of revascularization were achieved with mechanical thrombectomy than medical therapy.

Randomized clinical trials have demonstrated that evidence of complete revascularization on CT or MRI is more likely to be detected in stroke patients who undergo thrombectomy rather than best medical therapy. It remains unclear, however, what the clinical impact is of sustaining complete revascularization of the target vessel through 24 hours after treatment.

In the REVASCAT trial, 24-hour revascularization rate was included as a secondary outcome measure. For their paper published online March 14, 2017, in stroke, Mònica Millán, MD, PhD (Hospital Germans Trias, Barcelona, Spain), and her fellow REVASCAT investigators used an independent core laboratory to adjudicate vessel status at 24 hours using a modified arterial occlusive lesion classification system based on CT (94.2%) or MRI (5.8%). They also evaluated 24-hour infarct volume on CT imaging among 95 of the 103 patients in the thrombectomy arm and 94 of the 103 patients in the control arm of the REVASCAT trial.

Complete revascularization, defined as modified arterial occlusive lesion grade 3, was achieved in 70.5% of patients who underwent thrombectomy, compared with only 22.3% of controls (P < 0.001). A significantly greater rate of complete revascularization was seen with thrombectomy compared with medical therapy for lesions of the terminus internal carotid artery, M1, and tandem occlusions, but not for M2 occlusions.

In the thrombectomy group, two out of 63 patients (3.1%) with a modified TICI score 2b/3 after intervention showed arterial reocclusion, defined as a modified arterial occlusive lesion grade 0/1, at 24 hours.

Complete revascularization was associated with overall improvement in mRS score at 90 days in both the thrombectomy and control groups.

Association Between Complete Revascularization and Improved 90-Day Outcome

Any type of recanalization, defined as a modified arterial occlusive lesion grade 2/3, was associated with smaller infarct volumes in both arms of the trial.

Predictors of Outcome

“Importantly, patients who achieved complete revascularization in both thrombectomy and control group had similar distribution of the Rankin scores at 90 days, with equivalent proportion of patients with favorable outcome and mortality,” the researchers stress. They say this supports the notion “that revascularization within 24 hours poststroke onset is a powerful independent predictor of favorable functional outcome irrespective of treatment modality.”

Yet “excellent outcome,” amounting to an mRS of 0-1 at 90 days, “was only significantly higher in those patients with complete revascularization after mechanical thrombectomy,” they report. “Although the precise time when revascularization occurred in control arm cannot be determined, it is likely that higher rates of early revascularization in the intervention group compared with control group could explain this finding because longer onset to reperfusion time has been associated with a reduced likelihood of good outcome in most trials examining the clinical benefit of reperfusion (intravenous or endovascular).”

Additionally, Millán and colleagues note that the phenomenon of arterial reocclusion after successful endovascular revascularization—which occurred here at an incidence of 3.1%—is not well understood. “A potential underlying intracranial atherosclerotic disease has been hypothesized as reason of delayed arterial reocclusion, especially when residual stenosis remains at the target vessel immediately after thrombectomy,” they explain, adding that reocclusion’s effects on functional recovery should be studied through further meta-analysis of trial data.

Based on the current findings, the researchers conclude: “Regardless whether patients are treated with thrombectomy or best medical therapy, complete revascularization at 24 hours is a powerful predictor of favorable clinical outcome while revascularization of any type results in reduced infarct volumes.”

Source:

Millán M, Remollo S, Quesada H, et al. Vessel patency at 24 hours and its relationship with clinical outcomes and infarct volume in REVASCAT Trial (Randomized trial of revascularization with Solitaire FR device versus best medical therapy in the treatment of acute stroke due to anterior circulation large vessel occlusion presenting within eight hours of symptom onset). Stroke. 2017;Epub ahead of print.

Disclosures:

Millán reports no relevant conflicts of interest.

Related Stories:

• SWIFT PRIME Analysis Underscores Importance of ‘Time Is Brain’ Concept in Acute Stroke
• Study Offers More Evidence That Timing Matters for Mechanical Thrombectomy Outcomes
• REVASCAT: Thrombectomy’s Impact in Acute Stroke Extends to 1 Year

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