Coronary Disease Morbidity and Mortality in a Population

BACKGROUND:

Cardiovascular disease remains the leading cause of death in the U.S. Despite an encouraging decline in age-adjusted coronary heart disease (CHD) mortality, prevalent CHD continues to represent a major health burden, particularly in the elderly population. Most community surveillance programs, however, cannot fully characterize this problem because they are restricted to an upper age limit of 74 years and thus do not include the events occurring in an increasingly growing part of the population. Observational studies have questioned the existence of a change over time in the prevalence of anatomic coronary disease either at post-mortem examination or at coronary angiography. This remains to be further examined in a population-based setting. In addition, the natural history of myocardial infarction (MI) in the reperfusion area is unknown; in particular, there are no population-based data on the incidence of post-MI heart failure.

DESIGN NARRATIVE:

The records of all Olmsted County residents with a hospital discharge diagnosis of MI between 1979 and 1999 were reviewed, and standard epidemiologic MI validation criteria were applied; post-MI outcome over time was determined, including post-MI heart failure, angina, 30 day case fatality and long-term survival. In parallel with the analysis of time trends in CHD mortality, the autopsy reports were reviewed to examine whether the prevalence of coronary disease at autopsy has changed over time. These studies provided an assessment of the clinical and anatomical manifestations of CHD, including the outcome of acute MI, over a time period characterized by intensified primary prevention efforts and major changes in the treatment of acute CHD.

The study was renewed in July 2002 to continue surveillance of acute coronary heart disease events in order to address issues surrounding the diagnostic precision and risk stratification potential of troponin and high sensitivity C reactive protein (CRP) and to monitor secular trends in severity and treatment modalities. Novel approaches to the procurement of carefully timed blood samples allow direct measurement of the increase in number of cases of myocardial infarction using the new biomarker, troponin. An examination will be made of the prognostic value of quantitative peak troponin measured at 24 to 36 hours and high sensitivity C reactive protein measured early after symptom onset in the myocardial infarction cohort.