Disparities in MCS Use for STEMI-Related Shock Seen Across the US

For STEMI patients who develop cardiogenic shock, there are substantial disparities in the use of mechanical circulatory support (MCS) across the United States, according to a retrospective analysis.

Usage appears to be driven by social determinants of health—specifically sex, race, and type of insurance—and hospital characteristics, patterns that the study’s authors say “underscore the need for targeted interventions to address healthcare inequities and improve outcomes in this high-risk population.”

Lead author Abdul Rasheed Bahar, MD (Wayne State University, Detroit, MI), said what motivated the team to pursue this study was the knowledge that while MCS use is on the rise at many hospitals, not every center universally offers it to every candidate. With the advent of shock teams to comprehensively manage the acute condition, he told TCTMD, “we wanted to know: are there access gaps?”

This growing adoption of MCS doesn’t come cheap, Bahar noted. “That’s why health systems are being asked to measure equity as part of the quality of care they provide.”

Bahar said that, unfortunately, their findings follow a long line of studies showing sex and racial/ethnic imbalances in various aspects of cardiovascular medicine. “If you look at the literature, at least historically, there have been tremendous disparities in treatments and interventions in the United States. . . . That’s why performing these types of studies is important,” he stressed.

Behnam N. Tehrani, MD (Inova Schar Heart and Vascular, Falls Church, VA), who commented on the new data for TCTMD, described the study as “very impactful.” With more than 140,000 patients, it provides a window into how STEMI with cardiogenic shock is managed across the United States. “It’s probably the most contemporaneous one that I’ve seen, . . . and the takeaways of it are pretty stark,” he said.

These patients are “in the throes of illness, in extremis,” said Tehrani. “What it shows is that there are truly, on a national level, disparities in utilization [of] and access to mechanical circulatory support for [this indication].” That treatment gap is especially concerning, he added, given the positive findings of the DanGer Shock trial pointing to a survival benefit with support, at least in select patients.

“The onus is on us as physicians, as healthcare system leaders, and as national leaders to identify how we can bend this curve, because unfortunately it is an uneven playing field in this space,” he stressed. For Tehrani, shock networks are key in addressing disparities, such that MCS can be implemented “truly on the basis of need.”

Unequal Access

As outlined in a paper published online recently in JSCAI, Bahar and colleagues used ICD-10 codes from the Nationwide Inpatient Sample to identify 140,820 patients with STEMI complicated by cardiogenic shock between 2016 and 2021. In all, 18.8% of these individuals received MCS: extracorporeal membrane oxygenation (6.5%), intra-aortic balloon pump (62.8%), or the Impella percutaneous left ventricular assist device (Abiomed; 30.6%).

The MCS recipients, as a group, were significantly younger (mean 63.7 vs 67.2 years), more often male (74.2% vs 65.1%), and more likely to be treated at urban teaching hospitals (81.8% vs 75.0%) or large hospitals (63.9% vs 56.1%) than those not given MCS. They also were more likely to have private insurance (33.1% vs 26.1%) or self-pay (7.5% vs 5.7%) but less likely to have Medicare (47.4% vs 57.2%) compared with the no-MCS group. MCS-treated patients also had a lower prevalence of hypertension, dyslipidemia, smoking, prior MI, pulmonary disease, and prior CABG at baseline but a higher prevalence of protein-energy malnutrition and acute kidney injury.

Regionally, the highest use of MCS among STEMI patients with cardiogenic shock was in the South (41%). MCS was more common among patients transferred from another acute care hospital than among those who didn’t transfer (25.7% vs 20.5%), and when admissions occurred on weekdays versus weekends (29.0% vs 26.9%).

After adjusting for baseline demographic characteristics and comorbidities, female patients were less likely than male patients to be treated with MCS, as were African-American and Asian/Pacific Islander patients compared with white individuals. MCS use was less common for patients who had Medicaid as insurance and those admitted on a weekend, but it was more common at urban teaching hospitals. There was a nonsignificant trend toward more MCS in the southern United States, but no difference based on income level.

Likelihood of MCS for STEMI Patients With Cardiogenic Shock

Among men, African-American patients had a lower likelihood than white patients of receiving MCS (adjusted OR 0.79; 95% CI 0.67-0.93), as did Asian/Pacific Islander patients (adjusted OR 0.65; 95% CI 0.53-0.81). The same racial disparities weren’t seen among women.

The gaps identified by the study can be addressed at various levels, Bahar and Tehrani each suggested, pointing to efforts like ensuring speedy transfer to expert centers, removing obstacles like prior authorization, and including equity as a quality measure, among other things.

“As a first step, this should serve as a call to action to develop centralized shock networks, in which centers across various regions in the country work together to help implement standardized care for these patients, to identify who could potentially benefit the most, and to do it in a safe and then also a cost-effective manner.” said Tehrani.

Recently, as reported by TCTMD, the American College of Cardiology released clinical guidance with the hopes of encouraging best practices in cardiogenic shock.

Another example of a unified approach is the Society for Cardiovascular Angiography and Interventions’ new initiative focused on lactate clearance. The “very simple” metric, Tehrani said, “doesn’t require a lot of effort and time and financial resources, but it allows you to identify that there’s shock and then, using standardized protocols, identify the best mechanism to facilitate clearance.”

The American Heart Association also has launched a Cardiogenic Shock Registry, which Tehrani pointed out is currently seeking research proposals.

Given that their own analysis was retrospective, Bahar said there is a need for prospective studies to look at social determinants of health in shock. Of special interest is how these factors impact transfer patterns, with an eye toward what barriers are standing in the way of sending patients to expert centers, he said. Qualitative research that involves emergency medical services, clinicians, families, and patients could prove useful in understanding how decisions are being made as well.

And finally, Bahar added, “there could also be cost-effectiveness analyses by subgroup, so policymakers can invest where equity and outcome gains are greatest.”