Prevalence and outcome of occluded coronary arteries in non-ST-segment elevation myocardial infarction patients in a high-volume primary percutaneous coronary intervention centre

Background Conventional electrocardiogram (ECG) changes, such as ST elevation (STEMI) or non-ST elevation (NSTEMI), have long been the cornerstone for diagnostic categorisation of acute myocardial infarction. However, this has delayed timely interventions for patients with acute occlusive myocardial infarction (MI) with no ST- segment elevation, leading to prolonged hospitalisation and worsening outcomes1. Purpose The aim of this study is to identify correlations between specific ECG patterns, cardiac biomarkers, regional wall motion abnormalities (RWMA) on echo, and past medical history findings that could help distinguish between occlusive and non-occlusive MI, and predict one-year mortality for these patients. Methods Retrospective British Cardiovascular Intervention Society (BCIS) database analysis at a high-volume primary PCI centre in England, spanning 2015 to 2025.NSTEMI patients undergoing angiography were classified by pre-procedural infarct-related artery (IRA) flow (Thrombolysis in Myocardial Infarction [TIMI] 0 vs 1). Baseline characteristics were summarised by group. Univariate logistic regression evaluated associations with TIMI 0; peak troponin was log[x+1] transformed and sparse categories collapsed. A prespecified multivariable model (age, sex, diabetes, RWMA, and log-troponin) was fitted, and the model's sensitivity and performance were assessed. Results Of 3491 NSTEMI patients, 414 with TIMI 0/1 were recorded; 291 (70%) had TIMI 0, and 123 (30%) had TIMI 1. In univariate analyses, higher injury biomarkers were associated with complete occlusion: peak troponin (log[troponin+1]) increased the odds of TIMI 0 (OR 1.21, 95% CI 1.08–1.36, p=0.001, N=349), and peak CK (log[CK+1]) showed a similar association (OR 1.54, 95% CI 1.12–2.13, p=0.008, N=141). RWMA on echocardiography was also associated with TIMI 0. Presenting ECG changes (collapsed into no acute changes, ST depression, T-wave changes, and other) were not associated with complete occlusion (TIMI 0) on univariate analysis (ST depression p=0.911; T-wave changes p=0.258; other p=0.536, vs no acute changes). In the prespecified multivariable model, RWMA remained independently associated with TIMI 0 (adjusted OR 1.93, 95% CI 1.10–3.43, p=0.023). Log-transformed troponin was borderline after adjustment (p≈0.07). Adding BMI, hypertension, hypercholesterolaemia and 1-year mortality did not materially change results. Conclusion Many NSTEMI patients' angiography results showed complete artery occlusion despite non-ST-elevation presentation, highlighting limitations of the STEMI/NSTEMI paradigm. Presenting ECG patterns were non-discriminatory, whereas biomarker magnitude and regional wall motion abnormalities independently predicted TIMI 0 flow. These findings support a multimodal, physiology-based diagnostic approach and inform prospective studies aimed at developing a risk-stratification tool for acute occlusive myocardial infarction.