Reducing the incidence and mortality from myocardial infarction

The past three decades have witnessed major gains in outcomes of patients with acute myocardial infarction owed largely to the implementation of systems of care prioritising timely reperfusion, advances in antithrombotic and antiplatelet therapies, and the development of post-myocardial infarction heart failure therapies.1Collet JP Thiele H Barbato E et al.2020 ESC guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation.Eur Heart J. 2021; 42: 1289-1367Google Scholar, 2Ibanez B James S Agewall S et al.2017 ESC guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation: the task force for the management of acute myocardial infarction in patients presenting with ST-segment elevation of the European Society of Cardiology (ESC).Eur Heart J. 2018; 39: 119-177Google Scholar, 3O'Gara PT Kushner FG Ascheim DD et al.2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines.J Am Coll Cardiol. 2013; 61: e78-140Google Scholar, 4Lawton JS Tamis-Holland JE et al.Writing Committee Members2021 ACC/AHA/SCAI guideline for coronary artery revascularization: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.J Am Coll Cardiol. 2022; 79: e21-129Google Scholar, 5Reed GW Rossi JE Cannon CP Acute myocardial infarction.Lancet. 2017; 389: 197-210Google Scholar Preventative measures like smoking cessation, adoption of healthy aerobic lifestyles, and intensified treatment of risk factors including hypertension, diabetes, and hypercholesterolaemia have further contributed to reducing the burden of atherosclerotic coronary artery disease and decreased the incidence of age-adjusted myocardial infarction. Despite these successes, acute myocardial infarction remains a leading cause of death in industrialised countries,5Reed GW Rossi JE Cannon CP Acute myocardial infarction.Lancet. 2017; 389: 197-210Google Scholar and there remains much progress to be made. Central to guiding providers and public health policies in the pursuit of this progress is an understanding of the relative contributions of myocardial infarction event and case fatality rates to these secular trends in myocardial infarction mortality burden. These data are crucial when deciding how to invest, target, and implement preventive and interventional therapies among the general population. It is with this appreciation that the study by Ximena Camacho and colleagues in The Lancet Public Health is of importance.6Camacho X Nedkoff L Wright FL et al.Relative contribution of trends in myocardial infarction event rates and case fatality to declines in mortality: an international comparative study of 1·95 million events in 80·4 million people in four countries.Lancet Public Health. 2022; 7: e229-e239Google Scholar In one of the largest samples of any study of acute myocardial infarction to date, the authors analyse contemporary trends in event and case fatality rates for myocardial infarction across four jurisdictions with national health-care systems from 2002–15.6Camacho X Nedkoff L Wright FL et al.Relative contribution of trends in myocardial infarction event rates and case fatality to declines in mortality: an international comparative study of 1·95 million events in 80·4 million people in four countries.Lancet Public Health. 2022; 7: e229-e239Google Scholar This large sample size provides perhaps the most accurate estimation of event and case fatality rates of myocardial infarction to date, and allows for granularity when examining differences between demographic subgroups, which is often lacking from other studies. This adds meaningfully to our knowledge base and sets a high standard for evidence for epidemiological studies of cardiovascular disease moving forward. There are several valuable messages from Camacho and colleagues' work. First, consistent with other studies,3O'Gara PT Kushner FG Ascheim DD et al.2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines.J Am Coll Cardiol. 2013; 61: e78-140Google Scholar the authors report a marked decrease in the incidence and mortality from acute myocardial infarction among these geographically and politically disparate jurisdictions from 2002–15. Although significant heterogeneity in incidence and case fatality rates across regions were noted, the overall trend was consistent, and should be both a cause for celebration and an impetus to continue to invest in these favourable trends. Second, the overall reduction in mortality from myocardial infarction was attributable to both an improvement in case fatality rates, and a reduction in event rates to various degrees across locations, age, and sex. This is illustrative that both intensive primary and secondary prevention efforts contribute to these tangible gains. These data might further be informative when forming public health policy and guidelines. Among older people, case fatality appears to be the largest driver of total myocardial infarction mortality; targeted strategies to improve the acute management of older adults would be most effective. In contrast, in younger adults, particularly women, targeting myocardial infarction event rates with preventative efforts might make the largest difference in myocardial infarction-related mortality. Despite these messages, there are certain study limitations that deserve mention. Although this study describes gross trends in the incidence and outcomes of myocardial infarction, it is not able to assess which specific preventative efforts or treatments are most helpful, because it used administrative hospital and mortality records, which lack granularity. Additionally, although the study supports the uniform interpretation of coding definitions in individual jurisdictions, there remains a risk that systematic differences in documentation, coding, and interpretation might account, in large part, for differences in observed incidence and case fatality rates across different geographic regions. In addition, stratification of acute myocardial infarction by ST-elevation myocardial infarction or non-ST-elevation myocardial infarction, and even further by type I or type II, would be particularly insightful at an epidemiological level.4Lawton JS Tamis-Holland JE et al.Writing Committee Members2021 ACC/AHA/SCAI guideline for coronary artery revascularization: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.J Am Coll Cardiol. 2022; 79: e21-129Google Scholar, 7Thygesen K Alpert JS Jaffe AS et al.Fourth universal definition of myocardial infarction (2018).Circulation. 2018; 138: e618-e651Google Scholar Importantly, the authors are unable to adjust for patient characteristics and risk factors, or stratify based on intensity of illness. An adjusted analysis of mortality is necessary to properly compare case fatality across regions. Furthermore, these data should not be generalised to other nations, given that the authors found heterogenous trends even between these four high-income countries. Future studies should build on Camacho and colleagues' study, and address these opportunities. In the interim, we now have a pragmatic, contemporary analysis of event and case fatality that can serve as a foundation for progress, which is still direly needed. Guideline documents and policy makers might find this information useful in their efforts. Providers can take solace knowing that primary and secondary prevention truly makes a difference, as does acute interventional care of patients with myocardial infarction. Although certain demographic groups appear to benefit more from a prevention or acute treatment strategies than others, maximum investment on both fronts seems the most effective strategy to improve both event and case fatality rates from acute myocardial infarction. GWR and VM declare no competing interests. Relative contribution of trends in myocardial infarction event rates and case fatality to declines in mortality: an international comparative study of 1·95 million events in 80·4 million people in four countriesWhile the mortality burden of myocardial infarction has continued to fall across these four populations, the relative contribution of trends in myocardial infarction event rates and case fatality to declining mortality varied between jurisdictions, including by age and sex. Understanding the causes of this variation will enable optimisation of prevention and treatment efforts. Full-Text PDF Open Access