Implications of Site Selection Evaluated in United States Coronary Stent PMA Studies

May 11, 2026—The American College of Cardiology (ACC) announced the publication of an investigation of the enrollment implications of site selection in premarket approval (PMA) studies for coronary stents.

“Aligning Coronary Stent Trial Enrollment With the U.S. Intended-Use Population: Implications of Site Selection,” was published by Wayne B. Batchelor, MD, et al in JACC, the Journal of the American College of Cardiology. (2026; 87:2163–2176).

According to ACC, the investigators—including Dr. Batchelor; Robert M. Califf, MD; Roxana Mehran, MD; and colleagues—used pooled data from nine coronary stent PMA studies submitted to the FDA from 2003-2018. They identified 8,859 study participants across 196 sites in the United States. The sites were classified by United States region, surrounding county demographics, teaching status, Veterans Administration affiliation, trial volume, female principal investigator (PI) involvement, and number of acute hospital beds.

The PMA studies were found to not fully reflect the intended-use population (IUP) because of significant underrepresentation of minority patients and modest underrepresentation of women, noted ACC.

Among the total patient population, median age was 64 years, 30% were women, and 88% self-identified as non-Hispanic White compared with 12% as racial or ethnic minorities, including 6.0% who identified as Black and 4.1% as Hispanic.

As summarized by ACC, the results showed the following:

• Minority patients and women were underrepresented with participant-to-prevalence ratios (PPRs) of 0.48 and 0.77, respectively (with 0.80 considered the threshold for adequate representation). This did not change significantly across the 15-year study period.
• Racial and ethnic minority enrollment varied between sites and was predicted by West and South regions, county minority population, population density and per-capita income (R² = 0.5; P < .001).
• Female enrollment showed less variation and was poorly predicted by any research site characteristics, including presence of female PI involvement (non-VA status only, R² = 0.095; P < .001), although this was so rare (<6%) that the investigators noted the study may be underpowered to report on a possible relationship.

The investigators also found that using modeling estimates that reallocated enrollment from low to high minority enrolling sites could move PPRs within the 0.80 adequate representation threshold, stated ACC.

As quoted by ACC, the investigators stated, “A site selection strategy that accounts for regional and county-level demographics may normalize minority representation without compromising that of non-Hispanic Whites. However, the effect on enrollment of women would be minimal, underscoring the need for additional targeted interventions to enhance representation of women in cardiovascular device trials.”

James C. Blankenship, MD, and Carolina Ponce-Orellana, MD, discussed the study in an accompanying editorial comment, “A Step Toward Diversity and Inclusion in Cardiovascular Research Trials,” in JACC (2026;87:2177–2179). They stated, “[T]he responsibility to include adequate representation of all patient groups in research extends to the entire scientific community.”

According to ACC, Dr. Blankenship and Dr. Ponce-Orellana suggest that study sponsors could limit enrollment to minority populations, prioritize site selection on past enrollment performance, and focus on sites with female or minority PIs as additional ways to improve PPR—all answers to "a question that has not only been a thorny problem for decades, but that takes on new relevance in the current social climate of the [United States].”