Early changes in myocardial stunning and biomarkers after ST-elevation myocardial infarction compared to the takotsubo syndrome

Abstract

Background Takotsubo syndrome (TS) and ST-elevation myocardial infarction (STEMI) are both characterized by sudden cessation of myocardial contractions (myocardial stunning) as well as elevation of cardiac troponins and B-type natriuretic peptides (BNP). Whereas STEMI results in variable degrees of necrosis and persistent cardiac dysfunction, TS results in little to any necrosis and full recovery of cardiac function. No “head-to-head” comparison of the temporal resolution of myocardial stunning and serum biomarkers in STEMI versus takotsubo has been done. Purpose To compare the time course of the recovery of cardiac function and serum biomarkers over the acute and subacute phases of takotsubo and STEMI, with patients with STEMI further subdivided into anterior and non-anterior STEMI. Method The Stunning In Takotsubo and Acute Myocardial Infarction (STAMI) study is a prospective, multi-center study that enrolls patients with TS or STEMI without known pre-existing cardiac dysfunction. Echocardiography, laboratory testing (including troponins and NT-proBNP), and ECG are acquired within 4 hours after acute coronary angiography and at 24±6, 48±12, 72±12 hours and 7±1, 14±2, and 30±2 days. The primary endpoint is the proportion of reversible myocardial akinesia resolved after 72 hours (Figure 1), as determined by echocardiography. Secondary endpoints include troponin-I, troponin-T, and NT-proBNP. Results Preliminary results from 155 patients with STEMI (78 anterior STEMI and 77 non-anterior STEMI) and 32 patients with TS are presented in Figure 1. Mean (SD) age was similar for patients with takotsubo (67±14), anterior STEMI (68±11), and non-anterior STEMI (68±10). All 3 groups showed substantial recovery of cardiac function over the course of the study, with the most pronounced recovery of cardiac function in TS. Compared to both STEMI groups, the TS group also had lower troponin-I to troponin-T ratio, and higher NT-proBNP (Figure 2). The proportion of reversible akinesia that had recovered at 72 hours was similar in patients with TS, anterior STEMI and non-anterior STEMI (p=0.8414). Conclusion The STAMI study will provide the comprehensive assessment of cardiac function and serum biomarker profile of patients with takotsubo and STEMI over the early course of the disease. Preliminary data from the study suggest that early myocardial functional recovery is more substantial but follows a similar time-course in takotsubo and STEMI. The differences in the magnitude of troponin elevation after takotsubo versus STEMI were more pronounced for troponin-I than T. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): ERC - European Research Council