Current Management of Type 2 MI

Abstract

Background: Type 2 myocardial infarction (T2MI), or myocardial necrosis due to supply-demand mismatch, poses significant diagnostic and management challenges for clinicians. We conducted a detailed clinical characterization of management and outcomes of a large population of T2MI patients, comparing them to type 1 MI (T1MI) patients, to better characterize investigation, management and prognosis. Methods and Results: Chart review was performed on all hospitalized troponin-positive patients in the Calgary Health Region between January 2007 and December 2008, identifying those diagnosed with type 1 and 2 MI. Additional data was obtained from the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) registry and the Strategic Clinical Network for Cardiovascular Health and Stroke. Mortality was assessed at 30 days through to 4 years. After age and sex matching, 756 patients with T2MI were included and compared with patients with T1MI. Patients with T2MI had infrequent, non-specific symptoms. An initial electrocardiogram (ECG) was not performed in 6%, and 1/3 did not have subsequent ECGs performed. Investigations were performed infrequently, with no patient undergoing angiogram. Evidence-based medical therapy was seldom prescribed, with 25.5% prescribed ASA and 17.3% statin. Outcomes were poor compared to patients with T1MI, with T2MI patients experiencing significantly greater 30-day through 4-year mortality (30-day adjusted OR 6.59, 95% CI 3.47-12.53 and 4-year adjusted OR 1.65, 95% CI 1.23-2.22). Conclusions: In this large cohort of patients diagnosed with T2MI, ECG changes were common, further investigation for coronary disease was uncommon, and outcomes were worse than patients diagnosed with T1MI, even after adjustment for comorbidities. Further research is required to determine appropriate management approaches and improve clinical outcomes of this vulnerable patient population.