African-American, but Not Hispanic/Latina, Women Have More MIs After Stenting Than White Women

African-American and Hispanic/Latina women who receive everolimus-eluting stents have 1-year MACE rates similar to those of white women. But for reasons that aren’t yet clear, African-American women have a threefold higher risk of MI and are nearly twice as likely to undergo TVR compared with their white counterparts, according to a new analysis of nearly 1,900 female patients.

A previous analysis from the same group that pooled data from the same sources—the PLATINUM Diversity and PROMUS Element Plus postapproval studies—showed that women and minorities experience similar rates of MACE compared with white men but are at higher risk of non-stent-related ischemic events even after adjustment for baseline characteristics.

This time, the researchers focused their lens specifically on women. Their results were recently published online in Circulation: Cardiovascular Interventions.

“We need to do a deeper dive into the interaction between race, ethnicity, gender, and risk factors to understand the full impact of these characteristics on outcome,” said senior author Wayne Batchelor, MD (Inova Heart & Vascular Institute, Falls Church, VA). “And we have to dovetail into that discussion social determinants of health.”

Historically, the focus in gauging risk has been more on comorbidities and clinical characteristics, he told TCTMD. “The reality is there are other risk factors that we’re probably missing as it relates to how patients fare after interventions, including coronary stent interventions, even in the modern era.”

That MI risk is so elevated in African-American women, Batchelor said, “is something that’s completely gone under the radar screen because we’ve never looked at them. We’ve really never studied African-American women. If we’ve done studies, they’ve always been African-Americans, men and women [but cohorts] dominated by men. And if we’ve done studies on women, they’ve been predominately Caucasian.

“There’s this really interesting double whammy of being minority and female that seems to provide incremental risk, at least in terms of myocardial infarction,” he stressed.

The Double Whammy

Lead author Roxana Mehran, MD (Icahn School of Medicine at Mount Sinai, New York, NY), and her co-investigators combined data on 1,067 women from the PLATINUM Diversity and 806 women from PROMUS Element Plus who were implanted with everolimus-eluting stents. Most (76.1%) of the patients were white, 15.9% were African-American, and 5.7% were Hispanic/Latina.

There’s this really interesting double whammy of being minority and female that seems to provide incremental risk, at least in terms of myocardial infarction. Wayne Batchelor

Compared with white patients, African-American and Hispanic/Latina patients had a higher prevalence of diabetes and hypertension. African-American women tended to be older and have larger reference vessel diameters, but to also have less lesion calcification. Hispanic/Latina women, meanwhile, tended to have more lesion calcification but less tortuosity.

Adjusted for differences in medical history, lesion characteristics, and procedural factors, the risk of MACE (death, MI, or TVR) at 1 year was similar for African-American and white patients and for Hispanic/Latina and white patients. Independent predictors of MACE were renal disease, prior MI, silent ischemia, history of stroke, and multivessel disease.

For African-American women in particular, the risk of MI was sharply elevated at 1 year (HR 3.45 vs white women; 95% CI 1.72-7.14), as was the risk of TVR (HR 1.82 vs white women; 95% CI 1.10-2.94)—this despite the fact that they maintained dual antiplatelet therapy (DAPT) just as consistently.

Batchelor pointed out that there were some small differences in DAPT adherence, with Hispanic/Latina patients being slightly less likely be discharged on DAPT (91%) compared with African-American and white patients (96% and 94%, respectively). By 12 months, DAPT rates were comparable among all three groups, hovering around 84-85%. “There are some low-hanging fruit for us to go after for everyone but in particular . . . there may be some racial and ethnic groups who are more prone to having issues with compliance and we need to consider that,” he advised.

Details on social determinants of health were only available for women who took part in PROMUS ELEMENT PLUS. African-American and Hispanic/Latina patients, on average, were more likely to report having lower levels of education, less income, and less private insurance and they were more often single. Hispanic/Latina women were more likely to report being unemployed.

Further adjustments that took social determinants of health into account did not change the patterns in 1-year outcomes, Batchelor told TCTMD.

An Impetus for Change?

The tripling of MI risk among African-Americans “may be because of the greater burden of clinical comorbidities, socioeconomic and psychosocial stressors, healthcare access/insurance status, and perhaps enhanced thrombogenicity,” the investigators suggest.

For Batchelor, the study “provides a lot of impetus for us to study the biological, social, and clinical and angiographic underpinnings of the findings that we’re seeing."

While some of the discrepancies in outcomes may relate to known socioeconomic factors, like access to care, he said, it can’t be assumed that there aren’t any biological differences. For example, a 2008 paper by Gurbel et al showed that African-American woman had particularly active platelets. “There’s a signal in the literature, but we’ve never had the granularity to study it because we have not been able to have enough minority women in trials to get our head around this,” Batchelor said.

“I’m hoping that [our study] spurs a little bit more debate about how we ensure that [people] who have less voice are included in the studies that we do and get access to the treatment modalities that seem to be safe and efficacious,” he concluded.

Note: Mehran is a faculty member of the Cardiovascular Research Foundation, the publisher of TCTMD.