P2Y₁₂ Inhibitor Pretreatment in Non-ST-Segment Elevation Acute Coronary Syndrome: The NCDR Chest Pain-MI Registry

Background: Although high rates of P2Y₁₂ inhibitor pretreatment (defined as the administration before coronary angiography) for non-ST-segment elevation acute coronary syndrome (NSTE-ACS) have been reported, contemporary U.S. practice patterns are not well studied.

Objectives: The goal of this study was to investigate the temporal U.S. trends, variability, and clinical outcomes of P2Y₁₂ inhibitor pretreatment in NSTE-ACS.

Methods: Consecutive patients who underwent early invasive strategy for NSTE-ACS (coronary angiography ≤24 hours of arrival) in the National Cardiovascular Data Registry Chest Pain-Myocardial Infarction (MI) Registry were analyzed. A time-trend analysis was conducted on a complete cohort between January 1, 2013, and March 31, 2023. Subsequently, a more recent cohort (January 1, 2019, to March 31, 2023) with a complete set of variables was used to construct hierarchical regression models to quantify the variability in the use of pretreatment among operators and institutions. For this contemporary cohort, instrumental variable analysis, with operator preference as the instrument, was performed to compare the in-hospital outcomes between patients who received pretreatment and those who did not.

Results: Use of P2Y₁₂ inhibitor pretreatment decreased from 24.8% in 2013Q1 to 12.4% in 2023Q1. Among the contemporary cohort of 110,148 patients (2019-2023; mean age 63.9 ± 12.5 years; 33.0% female), 17,509 (15.9%) received pretreatment. Significant variability in P2Y₁₂ inhibitor pretreatment was observed (range: 0%-100%): hierarchical regression model demonstrated that 2 similar patients would have a >3-fold difference in the odds of pretreatment from 1 random operator or institution as compared with another (median OR: 3.74 [95% CI: 3.57-3.91] and 3.63 [95% CI: 3.51-3.74], respectively). Instrumental variable analysis demonstrated no significant differences in in-hospital all-cause death (1.5% vs 1.7%; P = 0.07), recurrent MI (0.6% vs 0.6%; P = 0.98), or major bleeding (2.7% vs 2.8%; P = 0.98) with pretreatment. However, in patients who underwent coronary artery bypass surgery, pretreatment was associated with a longer length of stay (11.2 ± 5.1 days vs 9.8 ± 5.0 days; P < 0.01).

Conclusions: In a national U.S. registry, we observed significant variability in the use of P2Y₁₂ inhibitor pretreatment among NSTE-ACS patients. Given the lack of clear advantages and the potential for prolonged hospital stays, our findings highlight the importance of efforts to improve standardization.