Interim results from an ongoing study demonstrated that that a higher pretreatment Alberta Stroke Program Early CT Score on computed tomography angiogram images is associated with better outcome following endovascular therapy.

“There is no standard imaging approach for endovascular therapy patient selection,” Dr. Donald Frei said at the annual meeting of the Society of Neurointerventional Surgery. “We’re trying to improve time from door to CT imaging and time from imaging to groin puncture, but we also need to be a little bit more sophisticated about patient selection. That’s what we tried to do in this study.”

Dr. Donald Frei

For the analysis, Dr. Frei, director of neurointerventional surgery for Radiology Imaging Associates/Swedish Medical Center in Denver, and his associates at 15 centers evaluated the influence of pretreatment ASPECTS from CTA source image on outcomes following endovascular therapy in the START (Stroke Treatment and Revascularization Therapy) trial, a prospective, single-arm multicenter trial that set out to study the influence of pretreatment core infarct size in 147 patients undergoing endovascular stroke therapy with the Penumbra system.

Imaging methods were at the direction of each investigator and included noncontrast CT, CTA-SI (CTA source images), CT perfusion, or MRI diffuse imaging. The current analysis focused on the preliminary CTA-SI results. ASPECTS was graded in a blinded fashion and analyzed according to a prior classification (0-4, 5-7, or 8-10) and the entire scale. Clinical outcomes were dichotomized as 90-day modified Rankin Scale (mRS) scores of 0-2 (good) vs. 3-6.

Dr. Frei reported interim results from 77 patients who met study criteria. Their mean age was 66 years, 56% were women, and their mean National Institutes of Health Stroke Scale score was 19. The majority of target vessel occlusions were in the middle cerebral artery (75.3%), followed by internal carotid artery (22.1%), and other areas (2.6%). (Dr. Frei noted that results from all 147 patients are expected to be presented at the upcoming International Stroke Conference.)

The median pre-ASPECTS on CTA-SI was 6. Of the 77 patients, 20 (26%) had a score of 0-4, 43 (56%) had a score of 5-7, and 14 (18%) had a score of 8-10.

Dr. Frei, who is also a member of the SNIS Executive Committee, reported that the rate of TIMI (Thrombolysis in Myocardial Infarction) 2-3 revascularization was 85.3%, the median time from groin puncture to aspiration discontinuation was 71.5 minutes, and 48.1% of patients achieved a good 90-day clinical outcome.

The mortality rate was 28.6%, and 32.5% suffered from intracranial hemorrhage. Of these, 20.8% were asymptomatic.

In general, the higher the pretreatment ASPECTS on CTA-SI, the better the outcome. For example, the rate of good outcomes was 20% for those with a pretreatment ASPECTS of 0-4, 56% for 5-7, and 64% for 8-10 (P = .08 for all). After adjusting for age and stroke severity, the researchers determined that a pre-ASPECTS score of 5-10 was an independent predictor of good outcome (odds ratio, 6.8; P = .006).

Univariate analysis demonstrated the following significant predictors of good outcomes: pretreatment ASPECTS greater than 4 (P = .0043), younger age (P = .01), lower pretreatment NIHSS (P = .04), shorter time from groin puncture to discontinuation of aspiration (P = .0004), and revascularization time (P = .0001).

In a prepared statement, Dr. Frei noted that although thousands of men and women suffer a stroke every day, “only a small percentage of those affected are treated with endovascular therapy. This study strongly suggests that a simple ASPECTS reading from a fast, easy-to-obtain CTA source image can guide patient selection for endovascular therapy, particularly those most likely to benefit from the Penumbra System” beyond the 3- to 4.5-hour window.

The START trial was sponsored by Penumbra Inc.

Dr. Frei said that he had no relevant financial disclosures to make.