P4574Marked changes in the incidence of subendocardial and ST elevation myocardial infarctions: a twenty-one year study

Abstract Background/Introduction The use of new biomarkers, pharmacologic and interventional therapies have resulted in marked changes of the type of myocardial infarction. Purpose The purpose of this study is to report on the changes in the incidence of subendocardial and ST elevation myocardial infarctions (STEMI) in the state of New Jersey from 1994 to 2015 and describe possible explanations for this secular change. Methods The rate of occurrence of ST elevation myocardial infarction (ICD9 410.00) and of subendocardial (NSTEMI, ICD9 410.70 to 410.72) myocardial infarction was studied using the Myocardial Infarction Data Acquisition System (MIDAS), a statewide database of all admissions for acute myocardial infarction in New Jersey with more than 30 years longitudinal follow up. Admissions for myocardial infarction and unstable angina as well as for conditions associated with troponemia (heart failure ICD9 418.XX, chronic kidney disease ICD9 584.XX, 585.XX, 403.XX, diabetes ICD9 250.XX) were also identified. Associations among variables were examined using logistic regression and linear error in variables (LEIV) models. Results During the time period under consideration, there was a decrease in the total number of MIs in New Jersey by 17.5%, the number of STEMIs decreased by 67.4%, while the rate of NSTEMIs increased by 85.8% (top panel). There was a complementary relationship between the annual number of admissions for unstable angina to the annual number of admissions for NSTEMIs (bottom panel). The effect was more pronounced between 1994 and 2002 and plateaued thereafter corresponding to widespread use of troponins in the diagnosis of acute coronary syndromes. Conclusions The marked change in the type of myocardial infarction was due in part to the use of troponins that resulted in the classification of patients with unstable angina as patients with subendocardial infarction. These data support regionalization of facilities specializing in immediate intervention in STEMI patients.