DAPT Underused for Minor Stroke, TIA

DALLAS — Fewer than half of patients were prescribed a dual antiplatelet therapy (DAPT) regimen after minor stroke or transient ischemic attack (TIA), a population-based registry showed.

For strokes with an NIH Stroke Scale (NIHSS) score of 3 or less, 41% got guideline-recommended DAPT, Jonathan Solomonow, MD, of the University of Maryland Medical Center in Baltimore, reported at the American Stroke Association’s International Stroke Conference.

Women, normal weight patients, and those without modifiable risk factors were more likely to get antiplatelet monotherapy.

“As for the overall undertreatment across the population, the possible speculation could be provider hesitancy to initiate DAPT due to concern for bleeding risks — instead opting for monotherapy, despite proven benefits outweighing potential risks,” he said.

While such minor stroke and TIA patients generally speaking should be on DAPT, the data didn’t provide enough detail to conclude that the prescribing rate was inappropriately low, cautioned session moderator Stuart M. Fraser, MD, of UT Health Houston McGovern Medical School.

Specifically, the etiology wasn’t clear, he told MedPage Today.

Following the CHANCE and POINT trials, the American Heart Association updated its guidelines with a Class Ia recommendation for a 21-day course of aspirin plus clopidogrel DAPT for patients with noncardioembolic ischemic stroke and NIHSS scores of 3 or less who didn’t get IV thrombolytics.

“It’s possible that that information has not spread out to every provider,” Fraser noted.

Clinical decision tools or electronic health record prompts could help, he suggested, “but I think we’re a long way off from having that kind of tool that is sort of a catchall for people who maybe see a stroke patient once a week instead of it being their only job.”

The study utilized the stroke clinical network of the University of Maryland Medical System’s nine primary stroke centers, of which one is a comprehensive stroke center. It’s a geographically diverse system spanning rural and urban settings. Querying the system’s Get With The Guidelines stroke registry data turned up 2,440 patients over age 18 (average 67) who had a TIA or acute ischemic stroke with an NIHSS of 3 or less on admission to the hospital network from January 2018 through December 2021, and who were not prescribed an anticoagulant on discharge or who were discharged without any antiplatelet.

Of those with an NIHSS of 3 or less, 995 (41%) were discharged on DAPT.

The major demographic predictor of DAPT prescription was gender, with 43% of men but 39% of women getting DAPT (P<0.04).

While women, on average, have strokes at later ages than men, elderly females were still prescribed DAPT less than were elderly males, suggesting the disparity for women was not due to age alone, Solomonow told attendees.

Another contributor could be that “we classically think that females have a higher chance of having a cardioembolic stroke, in which case you wouldn’t use DAPT,” Fraser added.

However, “this is not an isolated finding,” Solomonow said. “Rather, we know that there’s an extensive body of literature showing that women with cardiovascular disease tend to be undertreated. For example, women have higher rates of atrial fibrillation but are less likely to be started on anticoagulation and get ablation less often. Furthermore, women are also less likely to be started on statin therapy and less likely to reach targeted lipid goals.”

Patients with stroke risk factors were also significantly more likely to get DAPT, including patients with hypertension, hyperlipidemia, obesity or overweight, and diabetes (all P<0.01 or less). The same was true for those with prior TIA or stroke and those with coronary artery disease (P<0.001).

“In patients with fewer vascular risk factors there might be an unconscious bias and misconception that these patients are overall healthier and do not warrant aggressive targeted therapy,” Solomonow suggested.

The researchers also looked at a somewhat broader categorization of “minor” stroke, to encompass NIHSS scores as high as 5.

Among the 3,173 patients with an NIHSS of 5 or less on admission, 1,283 patients (40%) were prescribed DAPT on discharge.

“Very few differences existed when comparing the [NIH] Stroke Scale 5 versus 3 subgroups, meaning that there’s a large cohort of patients, those with an admission NIHSS of 4 and 5, that are being prescribed DAPT outside of guideline criteria, including by the POINT and CHANCE trials,” Solomonow said.

Limitations included data stemming from only one statewide hospital system and registry based on user input.