The Source for Neurovascular News and Education

March 29, 2024

 

Key Points:

  • Imaging findings predict clinical, imaging outcomes in patients with acute stroke
  • Endovascular therapy plus IV thrombolysis particularly beneficial in patients with target mismatch profile

 

Patients with the target mismatch (TMM) profile appear to be particularly good candidates for endovascular therapy following acute stroke, according to a preplanned analysis of the SWIFT PRIME study published online August 27, 2015, ahead of print in Stroke. Moreover, imaging findings were good predictors of imaging and clinical outcomes. 

Initially, enrollment was restricted to patients with the TMM profile, defined as MRI- or CT-assessed ischemic core lesion volume of ≤ 50 mL, Tmax > 10s lesion ≤ 100 mL, mismatch volume (hypoperfusion volume–ischemic core) ≥ 15 mL, and mismatch ratio (hypoperfusion/ischemic core) > 1.8. After 71 patients were enrolled, the protocol was changed to make perfusion imaging optional, but most patients continued to undergo perfusion imaging before randomization.SWIFT PRIME included 195 patients with acute stroke who were randomized to IV tissue-type plasminogen activator (tPA) alone or tPA plus endovascular therapy using the Solitaire device (Covidien). Baseline ischemic core lesions and hypoperfusion volumes were generated in real time using fully automated RAPID software (iSchemaView, Menlo Park, CA).

A prior analysis showed that baseline ischemic core volumes predicted 27-hour infarct volumes in patients who achieved reperfusion. In patients who did not reperfuse, baseline Tmax > 6s perfusion lesion volumes were associated with with 27-hour infarct volumes.

In this additional preplanned analysis, Gregory W. Albers, MD, of Stanford University School of Medicine (Palo Alto, CA), and colleagues evaluated how well baseline and follow-up imaging assessments predicted clinical and imaging outcomes in SWIFT PRIME.

Successful reperfusion and infarct volume measured at 27 hours both predicted functional outcome at 90 days, defined by the modified Rankin Scale (mRS) score. As infarct size increased, so did mRS score (P < .001). And as the degree of reperfusion improved, the percentage of patients who achieved a favorable clinical outcome at 90 days (mRS score 0-2) increased (P < .00001).

Patients with the TMM profile at baseline were more likely to achieve reperfusion, had less infarct growth and smaller infarct volumes, and were more likely to be functionally independent at 3 months in the endovascular therapy vs IV tPA-alone group.

There was also a trend toward a better response to endovascular therapy among patients with larger mismatch volumes at baseline (≥ 50 mL) compared with patients who had smaller mismatch volumes.

Call for Rapid Reperfusion

“These findings demonstrate that achieving successful reperfusion as quickly as possible is paramount to maximize the likelihood of attaining a good clinical outcome at 90 days in patients with acute ischemic strokes due to large vessel occlusions,” Josser E. Delgado Almandoz, MD, of Abbott Northwestern Hospital and St. Francis Regional Medical Center (Minneapolis, MN), told WLNCMD in an email. “Further, those patients who have a large ischemic penumbra at presentation, demonstrated by perfusion imaging, may derive the biggest benefit of prompt and successful reperfusion with mechanical thrombectomy.”

The imperative to achieve rapid reperfusion, continued Dr. Delgado Almandoz, “requires prompt transfer of these patients to comprehensive stroke centers with the capability to perform mechanical thrombectomy after intravenous tPA administration. Further, performing perfusion imaging should be strongly considered by operators to select those patients most likely to benefit from mechanical thrombectomy.”

Dr. Delgado Almandoz recommended that future studies focus on “determining whether patients who do not have a large mismatch by perfusion imaging at presentation may still derive some benefit from mechanical thrombectomy as well. In addition, further studies are needed to determine the efficacy of different mechanical thrombectomy techniques.”

 


Source:
Albers GW, Goyal M, Jahan R, et al. Relationships between imaging assessments and outcomes in Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke. Stroke. 2015;Epub ahead of print.

Disclosures:

 

  • SWIFT PRIME was funded by Covidien.
  • Dr. Albers reports having equity in and serving as a consultant for iSchemaView and having been a consultant for Covidien.
  • Dr. Delgado Almandoz reports serving as a consultant for Medtronic Neurovascular and Penumbra.