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Stroke Thrombectomy: Strict Mismatch Criteria Not Necessary After 16 Hours?

— Looser imaging criteria would open door to wider eligibility

Ƶ MedicalToday
 Closeup of an endovascular thrombectomy.

Endovascular therapy (EVT) remained beneficial in late-presenting stroke whether patients met DEFUSE 3 or DAWN imaging criteria, according to an analysis of pooled patient-level data from the AURORA database.

Stroke patients presenting 6 to 24 hours after they were last known well could enjoy reductions in 90-day disability after thrombectomy whether they had qualified by clinical mismatch (OR 3.57, 95% CI 2.29-5.57) or target perfusion mismatch criteria (OR 3.13, 95% CI 2.10-4.66).

Use of either mismatch profile was associated with benefit across the entire 6- to 24-hour window, Gregory Albers, MD, of Stanford University in California, and coauthors reported in a more than 500-person study published in .

"To our knowledge, this study provides the first data on the benefits of EVT among patients with a target perfusion mismatch profile beyond 16 hours after they were last known well. The associated benefits for these patients were substantial," the authors noted.

"Applying this finding to routine care would substantially increase the currently small proportion of patients presenting more than 6 hours after stroke onset who could receive this beneficial and reasonably safe therapy. This particularly applies to the patients in the 16- to 24-hour window who fulfill the target mismatch criteria, which are more inclusive than the clinical mismatch criteria," according to Jean-Claude Baron, MD, ScD, of Université de Paris.

Forthcoming international guidelines should reflect these findings, Baron suggested in an .

The AURORA collaboration pooled individual patient data from the DAWN, DEFUSE 3, ESCAPE, RESILIENT, , and studies.

Target perfusion mismatch criteria, based on ischemic core size on MRI or CT perfusion, had been used to select patients in the DEFUSE 3 trial.

Stricter DAWN-like clinical mismatch, on the other hand, requires information regarding patient's age and baseline NIH Stroke Scale score on top of MRI or CT perfusion results.

Current guidelines recommend thrombectomy in the 6- to 16-hour window for patients with a target perfusion imaging mismatch profile, or in the 6- to 24-hour window for those with a clinical imaging mismatch profile, according to Baron.

These criteria leave out approximately 70% of potential EVT candidates (i.e., those presenting with large vessel occlusion and NIH Stroke Scale scores ≥6 or within the 6- to 24-hour window), the editorialist noted.

For the present analysis, Albers and colleagues included 505 stroke patients who presented more than 6 hours after last known well. Of these patients, 276 were assigned to EVT and 239 to the control group.

Participants had a median age of 70 years. Women constituted 54.9% of the EVT group and 47.3% of controls. At baseline, NIH Stroke Scale scores averaged 16.4 and 17.2, respectively.

By imaging criteria, 295 individuals had sufficient records for a clinical mismatch profile, and 359 could be classified as having target perfusion mismatch.

Significant treatment benefit in these subgroups were observed across all time intervals -- tercile 1 (6-9.5 hours), tercile 2 (9.6-12.7 hours), tercile 3 (12.8-24.0 hours) -- with the highest odds ratios seen in tercile 3:

  • Clinical mismatch: OR 4.95 (95% CI 2.20-11.16)
  • Target perfusion mismatch: OR 5.01 (95% CI 2.37-10.60)

No significant treatment benefit was seen among the 132 people with an undetermined mismatch profile (OR 1.59, 95% CI 0.82-3.06), though the study authors cautioned that this analysis was underpowered. There was a significant interaction between treatment effects for the clinical and target perfusion mismatch subgroups versus the undetermined profile subgroup (OR 2.28, 95% CI 1.11-4.70).

Albers and coauthors highlighted the possibility that EVT's benefit may be greater in stroke patients who qualified as having target perfusion mismatch, but not clinical mismatch, due to excessively large ischemic core volumes.

  • author['full_name']

    Kate Kneisel is a freelance medical journalist based in Belleville, Ontario.

Disclosures

The AURORA collaboration was funded by a grant from Stryker Neurovascular.

Albers reported receiving consulting fees from Genentech and owning equity in iSchemaView. Multiple coauthors reported relationships with Stryker Neurovascular and other industry entities.

Baron had no disclosures.

Primary Source

JAMA Neurology

Albers GW, et al "Assessment of optimal patient selection for endovascular thrombectomy beyond 6 hours after symptom onset: a pooled analysis of the AURORA database" JAMA Neurol 2021; DOI: 10.1001/jamaneurol.2021.2319.

Secondary Source

JAMA Neurology

Baron J "Selection of patients for thrombectomy in the extended time window" JAMA Neurol 2021; DOI: 10.1001/jamaneurol.2021.1825.