Myocardial oxygen supply-demand imbalance causes type 2 myocardial infarction, which is becoming more prevalent as high-sensitivity cardiac troponin testing becomes available. Despite the fact that this diagnosis is linked to poor outcomes, doctors are still unsure how to evaluate and manage this diverse group of patients with type 2 myocardial infarction. About 8,064 consecutive individuals with elevated cardiac troponin concentrations were evaluated in a prospective cohort trial to identify patients with type 2 myocardial infarction. Patients who were fragile or had renal or hepatic failure were excluded. All individuals in the research had coronary (invasive or computed tomography angiography) and cardiac (magnetic resonance or echocardiography) imaging and the underlying causes of infarction were determined separately. The prevalence of coronary artery disease was the primary outcome.
Coronary and cardiac imaging reclassified the diagnosis in 7 patients with a preliminary diagnostic of type 2 myocardial infarction (median age, 65 years [interquartile range, 55–74 years]; 43% women): type 1 or 4b myocardial infarction in 5 patients and acute myocardial damage in 2 patients. The median cardiac troponin I concentrations in patients with type 2 myocardial infarction were 195 ng/L (interquartile range, 62–760 ng/L) at presentation and 1,165 ng/L (interquartile range, 277–3,782 ng/L) on repeat testing. The prevalence of coronary artery disease was 68% (63 of 93), with 30% of cases being obstructive (28 of 93). About 42% (39 of 93) of the patients had infarct-pattern late gadolinium enhancement or regional wall motion abnormalities, and 34% had left ventricular systolic dysfunction (32 of 93). Only 10 of the patients showed normal coronary and cardiac imaging. In 60% (38 of 63) and 84% (27 of 32), respectively, coronary artery disease and left ventricular systolic dysfunction were previously undiagnosed, with only 33% (21 of 63) and 19% (6 of 32) receiving evidence-based therapy.
In patients with type 2 myocardial infarction, systematic coronary and cardiac imaging revealed coronary artery disease in two-thirds and left ventricular systolic dysfunction in one-third. Most patients with type 2 myocardial infarction have undiagnosed and untreated coronary or cardiac illness, giving opportunity for the beginning of evidence-based therapy with significant potential to enhance clinical outcomes.