Taxonomy for Young Women With Acute MI
Do current acute myocardial infarction (AMI) classifications accurately define clinical phenotypes of young women?
Data from the VIRGO (Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients) study were used to develop a novel taxonomy for young adults (<55 years) with AMI. The VIRGO study is a prospective cohort study of 2,009 women and 976 men, aged 18-55 years, diagnosed with AMI. A subset of patients (n = 600) was initially classified using the Third Universal Definition of MI. Heterogeneity was found to exist within type 2 AMI. Thus, 54 patients were unclassified. Patients were then grouped by shared clinical characteristics to distinguish unique clinical phenotypes. In classifying the entire cohort, those with no catheterization data, missing medical records, or who had received fibrinolytic therapy were excluded.
A total of 2,802 VIRGO participants were included in this study, of which 67.6% were women. Using the current universal classification system, 504 patients were classified as type 1, 40 as type 2, and 2 as Type 4b. More than 50% of those classified as type 2 had no significant coronary artery disease upon coronary angiography. The final VIRGO taxonomy classified the 2,802 participants into classes including; Class 1, plaque-mediated culprit lesion (82.5% of women; 94.9% of men); Class 2, obstructive coronary artery disease with supply-demand mismatch (2a: 1.4% women; 0.9% men); and without supply-demand mismatch (2b: 2.4% women; 1.1% men); Class 3, nonobstructive coronary artery disease with supply-demand mismatch (3a: 4.3% women; 0.8% men) and without supply-demand mismatch (3b: 7.0% women; 1.9% men); Class 4, other identifiable mechanism: spontaneous dissection; vasospasm; embolism (1.5% women; 0.2% men); and Class 5, undetermined classification (0.8% women; 0.2% men).
The investigators concluded that approximately one in eight women under the age of 55 years with an AMI are not able to be classified by the current Universal Definition of MI. The investigators, using data from a large study of young adults presenting with AMI, proposed a novel taxonomy that may advance current understanding of AMI, particularly among women.
This new taxonomy uses clinical variables, easy obtained at the time of admission. Furthermore, as the authors point out, studies already completed as well as registries would likely be able to reclassify their participants based on commonly collected factors available. Further research to understand this taxonomy, in particular among women presenting with AMI, is warranted.
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