Abstract 139: A Novel Taxonomy for Acute Myocardial Infarction in Young Women
Background: In young women, the mechanism of injury in AMI is heterogeneous. Current classification schemes may not accommodate the breadth of phenotypic presentations in this population.
Methods: We aimed to develop a new taxonomy for young women with AMI based on a random sample of patients enrolled in VIRGO, a multinational cohort study of young (≤55y) AMI patients. All met criteria for AMI with elevations of cardiac biomarkers and either chest pain or ECG changes. Five physicians abstracted data from the medical record using a structured instrument. Chart review focused on domains hypothesized to be relevant to clinical care and prognosis: clinical symptoms (e.g., chest pain, trigger, abruptness); clinical substrate for supply-demand mismatch (criteria defined in the abstraction instrument); underlying mechanism (assigned with probable/definite certainty); angiographic findings, (e.g., culprit artery); LV systolic function; and troponin elevation. We classified AMI phenotypes as Type I (plaque rupture/thrombus), Type II (supply-demand mismatch) or Type 4b (stent thrombosis), based on the 3rd Universal Definition. Using a systematic, empirical approach we developed a taxonomy by: (1) investigating heterogeneity within the current classification system, and (2) grouping patients with similar clinical characteristics into distinct classes, iteratively evaluating face validity with cardiologists.
Results: According to the 3rd Universal Definition, patients (n=598, 69% female; mean age 47y) were classified as: Type 1: 504 (84%); Type 2: 39 (7%); Type 4b: 2 (<1%). Among these types, we identified few specific clinical entities of AMI, e.g., embolism, n=2; vasospasm, n=3; takotsubo, n=4. An additional 54 (9%) patients had no identifiable mechanism and were unable to be classified; of these 51 were women. Iterative grouping of patients by clinical presentation yielded 5 phenotypes (Table).
Discussion: Nearly 1 in 10 young AMI patients are not captured by the current classification system; most are women. Moreover, there is wide heterogeneity in clinical presentation and extent of CAD among Type II AMI. A novel taxonomy may improve the complete classification of young women with AMI.
Author Disclosures: E.S. Spatz: None. L. Curry: None. C.P. Gross: None. F.A. Masoudi: None. R. Dryer: None. H. Bueno: None. J.F. Lampropulos: None. S.I. Chaudhry: None. S. Zhou: None. G. D'Onofrio: None. J.A. Spertus: None. B. Safdar: None. A.J. Lansky: None. H.M. Krumholz: None.
- © 2014 by American Heart Association, Inc.