CT Angiography Following Alteplase May Reduce Avoid Surgeries

September 27, 2018

Clinical and imaging biomarkers were associated with intracranial thrombus recanalization among patients with acute ischemic stroke.

Computed tomography angiography (CTA) scans show if alteplase is effective among patients with acute ischemic stroke, reducing referrals for surgery, according to a study published in the Journal of the American Medical Association.

Researchers from Canada, Saudi Arabia, Spain, Korea, the Czech Republic, the United States, Turkey, and Australia performed a prospective cohort study of 575 patients with acute ischemic stroke to examine recanalization over time across a range of intracranial thrombus occlusion sites and clinical and imaging characteristics in patients with ischemic stroke treated with intravenous alteplase or not treated with alteplase.

All patients, median age 72 years, had acute ischemic stroke and intracranial arterial occlusion demonstrated on CTA; 51.5 percent of the patients were male. The researchers identified the demographics, clinical characteristics, time from alteplase to recanalization, and intracranial thrombus characteristics (location and permeability) defined on CTA. The main outcomes and measures included recanalization on repeat CTA or on first angiographic acquisition of affected intracranial circulation obtained within 6 hours of baseline CTA, defined using the revised arterial occlusion scale (rAOL) (scores from 0 [primary occlusive lesion remains the same] to 3 [complete revascularization of primary occlusion]).

The results showed that the median time from patient last known well to baseline CTA of 114 minutes (IQR, 74-180). A total of 275 patients (47.8 percent) received intravenous alteplase only, 195 (33.9 percent) received intravenous alteplase plus endovascular thrombectomy, 48 (8.3 percent) received endovascular thrombectomy alone, and 57 (9.9 percent) received conservative treatment. The median time from baseline CTA to recanalization assessment: 158 minutes (IQR, 79-268) and median time from intravenous alteplase start to recanalization assessment: 132.5 minutes (IQR, 62-238).

Successful recanalization occurred at an unadjusted rate of 27.3 percent (157/575) overall, including in 30.4 percent (143/470) of patients who received intravenous alteplase and 13.3 percent (14/105) who did not (difference, 17.1 percent).

Among patients receiving alteplase, the following factors were associated with recanalization:

• Time from treatment start to recanalization assessment
• More distal thrombus location, e.g., distal M1 middle cerebral artery (39/84) vs internal carotid artery (10/92)
• Higher residual flow (thrombus permeability) grade, e.g., hairline streak (30/45) vs none (91/377)

The researchers concluded that among patients with acute ischemic stroke, three signs (more distal thrombus location, greater thrombus permeability, and longer time to recanalization assessment) were associated with recanalization of arterial occlusion after administration of intravenous alteplase; among patients who did not receive alteplase, rates of arterial recanalization were low. These findings may help inform treatment and triage decisions in patients with acute ischemic stroke, they wrote.