A significant proportion of patients with NSTEMI had acute coronary occlusions (ACOs), and ACO was associated with worse in-hospital outcomes among patients in the NSTEMI cohort, according to a recent study published in JACC: Cardiovascular Interventions.

Using data from ACC's CathPCI Registry, Riyad Yazan Kherallah, MD, et al., included 1,198,544 patients with STEMI or NSTEMI who underwent PCI between April 1, 2018, and June 30, 2023. Patients were categorized as STEMI (26%), NSTEMI-ACO (11%) or NSTEMI-no-ACO (63%). Overall, 15% of NSTEMI patients had ACO. The authors investigated a composite primary outcome of in-hospital stroke, myocardial infarction or cardiovascular mortality.

Patients with NSTEMI-ACO were more likely to suffer the composite primary outcome vs. patients with NSTEMI-no-ACO (adjusted odds ratio [aOR], 2.26; 95% CI:,2.18-2.34; p<0.001) but less likely compared to patients with STEMI (aOR, 0.54; 95% CI, 0.52-0.56; p<0.001). Patients with NSTEMI-ACO were also more likely to suffer cardiogenic shock, ventricular arrhythmias and in-hospital cardiac arrest compared to patients with NSTEMI-no-ACO.

"We report a substantial 15% incidence of NSTEMI-ACO when using a definition of 100% ACO, but this rose to 24% when including culprit arteries with TIMI flow grade 0 to 1, which is concordant with prior reported frequencies of 20% to 25%," note Kherallah and colleagues. "Although the 100% ACO definition is potentially more specific, it likely underestimates the true prevalence of ACO because of the dynamic nature of ACO."

In an accompanying editorial comment, Stephen W. Smith, MD, and Jose Nunes de Alencar, MD, FACC, add that "the adjusted odds ratio of 0.54 vs. STEMI is not reassuring. These patients had far more events than those with NSTEMI-no-ACO, and this invites comment on some biases. Entry into this cohort required reaching the catheterization laboratory."