Race Gap Closing for Stroke Thrombectomy, but Work Remains

Use of endovascular therapy (EVT) for acute ischemic stroke took off in the United States after the release of several trials establishing its safety and efficacy in 2015, yet some disparities across racial/ethnic groups remain, an analysis of the American Heart Association’s (AHA) Get With The Guidelines (GWTG) – Stroke program shows.

Before 2015, Black patients were less likely than their white peers to undergo endovascular therapy (OR 0.68; 95% CI 0.58-0.78), a difference that became smaller but remained significant in more recent years (OR 0.83; 95% CI 0.76-0.90), Faheem Sheriff, MD (Texas Tech University Health Sciences Center, El Paso), reported today during the virtual International Stroke Conference 2021.

“While there is an overall improvement in EVT utilization across all race and ethnic groups, likely corresponding with the publication of these groundbreaking trials in 2015 and guideline changes, there are disparities and these disparities persist, although they are narrowing,” he said during a media briefing. “So there is good news, but there is work that remains to be done.”

Additional research is also needed to explore why Black patients appear to have similar functional outcomes at discharge after an acute stroke compared with white patients then have worse 3-month outcomes, he said.

“There need to be concerted efforts to convert these observations of race and ethnic disparities into actions, and this has been a call to action from the AHA presidential advisory,” Sheriff stressed. “I think such a lifesaving therapy needs to be more uniformly distributed and more uniformly available to ensure that the benefits are available to all groups.”

‘An Important and Surprising Finding’

Racial/ethnic disparities in the use of acute stroke treatments, including both thrombolytic therapy and mechanical thrombectomy, have been seen before, Sheriff noted. One prior study showed that Black and Native American patients were less likely to undergo endovascular therapy compared with other groups, and a subsequent 2015 analysis of the GWTG – Stroke database confirmed the disparity among Black patients.

Sheriff said his team wanted to explore whether anything changed after 2015, a year in which several trials established mechanical thrombectomy as a safe and effective treatment for patients with acute ischemic strokes caused by large-vessel occlusions.

They, too, turned to the GWTG – Stroke database for answers. Their analysis, which used data gathered between April 2012 and June 2019, included 302,965 patients who were deemed to be potential candidates for endovascular therapy based on their arrival to the hospital within 6 hours of symptom onset and an NIHSS score of greater than 6. Overall, 14% of patients ultimately received thrombectomy.

Use of endovascular therapy increased over the study period across all racial/ethnic groups, particularly after 2015. However, both Black and Hispanic individuals were slightly underrepresented in the thrombectomy group compared with their representation in the overall acute stroke population.

There are several possible reasons for the disparity, Sheriff said, including systemic racism at the structural and provider levels; lower use of emergency medical services and later arrival to thrombectomy-capable centers, possibly related to a lack of awareness of stroke symptoms, in certain racial/ethnic groups; or mistrust of the healthcare system. “And I think this is very important, because there are historic inequalities that have led to this mistrust, and these need to be addressed,” Sheriff said.

Turning to outcomes, Black patients fared better than white patients over the short term, with a lower likelihood of discharge to hospice or inpatient mortality both before and after 2015 (OR 0.60 and 0.61, respectively). Similar trends, which became significant after 2015, were seen in Hispanic and Asian patients.

Sheriff said these findings could be related to improving access to acute stroke care across racial/ethnic groups or to differences in attitudes around end-of-life care. Non-Hispanic white patients, for instance, have been shown to have better access to and use of palliative care, as well as a greater tendency to withdraw care.

Functional outcomes and ambulation at discharge did not, however, differ by race/ethnicity, Sheriff reported, and by 90 days, the likelihood of a good functional outcome (modified Rankin Scale score of 0 to 2) was lower in Black and Asian patients, a disparity that was significant after 2015. “This is an important and surprising finding,” he said.

Closing Remaining Gaps

Sheriff said the reason for poorer 3-month outcomes among Black and Asian patients, despite better or comparable short-term outcomes, is multifactorial. Prior studies have shown that Black patients experienced delays in inpatient rehabilitation and home health services and that functional status on admission and at discharge from rehab after a stroke varies by race/ethnicity. Medication adherence might be a factor as well.

Louise McCullough, MD, PhD (University of Texas Health Science Center at Houston), told TCTMD it’s not clear what explains the discrepancy, but said it’s possible Black and Asian patients aren’t getting the same services after leaving the hospital that white patients are.

“It’s very important to follow people not just at hospital discharge, and to have very robust rehab and stroke systems of care for secondary stroke prevention,” she said. “And then you can check in on these patients 2 months after discharge to make sure that they’re going in the right direction and getting the services they need.”

McCullough cautioned, however, that a registry like the GWTG – Stroke database is best for looking at overall trends and doesn’t always have the level of detail needed to dig into what might be behind some of the observed disparities.

In this study, for example, patients were selected based on the timing of presentation and an NIHSS score greater than 6, which doesn’t necessarily mean that they were candidates for thrombectomy. Some of the differences seen in use of endovascular therapy by race/ethnicity could have been related to differential impacts of certain risk factors and the types of strokes they cause across those groups, McCullough said, noting that Black patients are more likely to have hypertension and diabetes, which are associated with small-vessel strokes that are not amendable to thrombectomy.

That said, the stroke community needs to remain vigilant to ensure that disparities in care are addressed, she stressed. “We are closing the gap, and that is a good trend, but we’ll have to watch it carefully to make sure that gap completely closes.”

Sheriff said about the findings of the study: “I think it’s a good news story, and I think we need to capitalize upon it. I also think we need to be aware of the fact that when there is good news, we try to understand why we are reaching that point and not to lose any of the gains that have been made.”