Treatment delay in STEMI is associated with heart failure and mortality. National data from the Norwegian myocardial infarction register

European guidelines in ST-segment elevation acute myocardial infarction (STEMI) recommends a primary PCI (P-PCI) strategy if wire crossing of the occluded artery can be performed within 120 min of ECG diagnosis. A large proportion of the Norwegian population lives in remote geographical areas where P-PCI may not be performed expeditiously. Time delay from first medical contact to primary PCI is expected to be related to outcomes like heart failure and mortality. Norwegian hospitals are by law required to register clinical data for all patients treated for acute myocardial infarction in the Norwegian Myocardial Infarction. The register includes >90% of eligible patients.

The aim of the study was to investigate the association of time from first medical contact (FMC) to P-PCI with heart failure (EF <50%) and mortality.

The study includes all patients registered during 2015–2018 in the Norwegian Myocardial Infarction Registry with STEMI who were <85 years of age and had <12 hours from symptom onset to FMC. For patients with missing values, FMC was calculated as time of prehospital ECG minus 10 minutes. The primary outcome variable was heart failure (defined as ejection fraction <50% during hospitalization) or all-cause mortality within 1 year after hospitalization. We calculated ORs (95% CI) adjusted for age, gender, and history of myocardial infarction, hypertension, diabetes, and heart failure.

During 2015–2018 a total of 6398 STEMI patients <85 years of age were registered in the Norwegian Myocardial Infarction Registry with less than 12 hours from symptom onset to FMC. Time delay from FMC to P-PCI were <90 minutes, 90–119 minutes, and >120 minutes in 40%, 25%, and 35% of the patients, respectively. Compared to patients with P-PCI within 90 minutes after FMC, the multivariable adjusted OR (95% CI; p-value) for heart failure or 1 year mortality was 1.05 (1.02–1.08; p<0.01) for patients with P-PCI within 90–119 minutes after FMC, and 1.05 (1.02–1.08; p<0.001) for patients with P-PCI >120 minutes after FMC. The corresponding ORs for 1 year mortality were 1.01 (0.99–1.02) and 1.03 (1.02–1.04), respectively, and the corresponding ORs for EF<50% were 1.07 (1.04–1.11) and 1.07 (1.04–1.11).

In Norway, only 40% of STEMI patients undergo P-PCI within 90 minutes after FMC, and 35% of patients undergoes P-PCI >120 minutes after FMC. Time delays of more than 90 minutes after FMC are associated with increased risk of heart failure and mortality. A fibrinolysis strategy may be preferred over P-PCI for a substantial proportion of STEMI patients.

Type of funding source: None