Medical Student University of British Columbia Victoria, British Columbia, Canada
Background: Myocardial infarction (MI) remains a leading cause of morbidity and mortality worldwide, significantly impacting patients, families, and healthcare systems. MI can be treated by optimal medical therapy alone (OMT), by percutaneous coronary intervention (PCI) or by surgical coronary artery bypass graft (CABG). Unfortunately the 5-year mortality for MI in Canada reportedly exceeds 20%. Furthermore, over 7% of patients are said to experience recurrent MI within one year.
METHODS AND RESULTS: We accessed the British Columbia Chronic Disease Registry incidence reports, Vital Statistics Agency records of deaths, and Medical Services Plan billing records, spanning 2000-2023 using the provincial Ministry of Health Data Platform. We included 80,113 patients aged 20-79 that experienced their first MI over 2000-2022 and received diagnostic angiograms. We used a 10 year follow-up period. Outcomes were classified as one of the following, in this order: Death, Recurrent MI treated by CABG, PCI, or OMT, PCI for reasons other than MI, (Invasive) Diagnostic Angiogram, or None. The data are visualized in Figure 1.
Among the initial MIs 12,178 (15.2%) were treated by CABG, 15,154 (18.9%) by OMT, and 52,781 (65.9%) by PCI. The all-cause mortality was 3.0% at 1-year follow-up,10.0% at 5 years, and 21.4% at 10 years. Recurrent MI occurred in 1.9% of cases within 1 year, 8.4% within 5 years, and 15.1% within 10 years. Among patients who experienced a recurrent MI, initial MI was treated by CABG in 12.4% of cases, OMT in 18.7%, and by PCI in 68.8%. Recurrent MI was treated by CABG in 8.2% of cases, OMT in 42.0%, and PCI in 49.9%.
Among patients who underwent PCI for reasons other than recurrent MI, the initial MI had been treated by CABG in 8.7% of cases, by OMT in 11.4%, and by PCI in 79.8% (Figure 2).
Of the patients with no defined events, 17.0% had initial MI treated by CABG, 21.3% OMT, and 61.7% PCI.
Conclusion: The morbidity and mortality of initial MI patients treated at catheterization and CABG-capable centers in BC are significantly lower than previously reported national averages for undifferentiated MI populations. It was significantly (Chi-Squared P<.001) more common to undergo PCI at any time subsequent to the primary MI if the initial MI was treated with PCI.
