A new study has found several racial disparities after mechanical thrombectomy for stroke with respect to post-procedure management and outcomes. Vineeth Thirunavu of Northwestern University Feinberg School of Medicine, Chicago, USA, presented the data at the Society of NeuroInterventional Surgery’s (SNIS) 17th Annual Meeting (4–7 August), which detailed key findings from the Neurovascular Quality Initiative-Quality Outcomes Database (NVQI-QOD) registry.
Specifically, Thirunavu explained that minority groups, including Hispanics, Asians, and African Americans, exhibited worse immediate post-procedural outcomes and a greater length of in-hospital and intensive care unit (ICU) stays.
“Race seems to be implicated in the length of treatment for acute ischaemic stroke,” he told the online audience. However, he said that the registry yielded an “interesting finding” in that in-hospital mortality for African Americans appears to be lower compared to their Caucasian counterparts. “This finding does not necessarily correlate with the findings that you would expect with longer length of stay and more ICU days.”
Discussing this finding further, Thirunavu added that in terms of outcome variables—modified Rankin scale (mRS) score and 90-day mRS—no difference in the rate of favourable outcome between races was observed, when excluding mRS scores of six.
Speculating as to why in-hospital mortality for African Americans was significantly lower, he said: “It could be a cultural thing, or not staying on the support of care, but we really have to do more research to see at what level these disparities are occurring at; is a patient level, a genetic level, or are healthcare providers treating patients differently?”.
Discussing the led the team to initially investigate racial disparities, Thirunavu said that since endovascular therapy has become the standard of care for stroke, research has focused on the disproportionate burden of stroke and cerebrovascular disease on African Americans. “Some studies have also looked into other minority groups […] but that research has focused on differences in the utilisation and access to mechanical thrombectomy; not a lot of research carried out has been on outcomes after mechanical thrombectomy, in terms of mRS scores or National Institutes of Health Stroke Scale [NIHSS] scores,” he added.
Therefore, according to Thirunavu, the current study utilised real-world evidence from the NVQI-QOD registry, enabling the team to study racial disparities in a large group of patients throughout the USA. In total, he reported that 3,261 patients from 23 US centres across 17 states, over a five year time period (January 2015–March 2020), were included.
He pointed to a slide displaying the population breakdown by race. It showed that 2,484 patients were Caucasian, 563 African American, 109 Hispanic, and 105 Asian. He admitted that there might be a slight underrepresentation of Hispanics in the cohort.
“We used a robust set of outcome variables; we were able to look up days to follow-up, and in-hospital mortality. In addition to the initial statistical analysis, we looked at regression models which controlled for demographics, comorbidities, intravenous tPA [tissue plasminogen activator] thrombolysis and pre-stroke functional measures,” Thirunavu explained.
However, he pointed to a particular caveat with the outcome variables, acknowledging that the registry contains some limited data. “Only 33% of patients that are alive at 90 days had mRS scores reported; two-thirds of the data are still up for grabs, and we do not know how those individuals faired,” he told viewers, and further emphasised that mRS, especially at 90-days, is an important outcome variable after mechanical thrombectomy.
In terms of moving forward with these findings, Thirunavu told the SNIS audience that time-to-event analyses need to be carried out. He noted that the NVQI registry has some data on this. “We also need to look into the relationship between sex and race, and think about how we can improve mRS data collection for registries, and have better outcome variables,” he concluded.
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