Prevalência, etiologia e características dos pacientes com infarto agudo do miocárdio tipo 2

Abstract

Background

In clinical practice, type‐1 (coronary thrombosis) and type‐2 (imbalance between oxygen demand and supply) acute myocardial infarction (AMI) are not clearly differentiated. The aim of this study was to evaluate the prevalence and etiology of type‐2 AMI and compare its profile with that of type‐1 AMI.

Methods

Patients admitted with ST‐segment elevation AMI (STEMI) < 12 hours of symptom onset, and referred for coronary angiography, from 2009 to 2013, were analyzed.

Results

There were 1,960 patients included; 1,817 were analyzed, of whom 1,786 (98.3%) had type‐1 AMI, and 31 (1.7%), type‐2. All patients with type‐2 AMI showed no significant coronary lesions, and 36% of the cases had apical dyskinesia. Type‐2 AMI patients had, in general, a clinical and laboratory profile that was similar to those with type‐1, except for the younger age, lower levels of myocardial necrosis markers, higher probability of having pre‐TIMI 3 flow and higher left ventricular ejection fraction. At 30 days, mortality (3.2 vs. 9.0%; p = 0.23) and the occurrence of death, reinfarction, or need for target‐vessel revascularization (3.2 vs. 13.0%; p = 0.09) were numerically lower in type‐2 AMI.

Conclusions

Few patients with STEMI were classified as type‐2; they had structural abnormalities, isolated or associated with the absence of significant lesions; showed little difference regarding the clinical and laboratory profile, and similar clinical outcomes at 30 days, when compared to patients with type‐1 AMI.