Troponin and NT-proBNP in the prediction of impaired myocardial deformation after STEMI

Abstract

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): University of Medicine and Pharmacy “Iuliu Hațieganu” Cluj- Napoca. Introduction One adverse consequence that may follow an ST-elevation myocardial infarction (STEMI) is left ventricular (LV) remodeling. The majority of evidence indicates speckle-tracking echocardiography and global longitudinal strain may identify early changes in deformation after MI, while circumferential strain (GCS) is less extensively studied. However, since strain is thought to be afterload-dependent, the global work index (GWI), a novel afterload-incorporating parameter recently evolved. Objective The aim of this study was to determine whether the levels of high-sensitive troponin and NT-proBNP, two variables known to be of prognostic significance in STEMI, might indicate whether GCS and GWI are more impaired after STEMI. Material and methods 60 patients with STEMI and preserved LVEF who underwent PCI were included in the study. Using a Vivid E95 scanner, early echocardiography (2–4 days) was performed, and the EchoPac BT13 software (GE Vingmed ultrasound) was used for analysis. Both conventional and deformation parameters were assessed. GWI was determined by using pressure-strain loops (strain and estimated LV pressure from the peak arterial brahial cuff pressure). ROC curves were used to determine the optimal cut-off values of Troponin and NT-proBNP to predict the values below the median for each of the studied parameters (GCS and GWI). Results The mean age of the patients was of 68±13 years and 55% were male. The majority of the patients presented with anterior MI (n=29, 48.3%), followed by inferior MI (n=25, 42%). Patients frequently reported hypertension (n=45,75%), while others had dyslipidemia (n=15, 25%), diabetes (n=8, 13.3%), and smoking (n=23, 38.3%) as cardiovascular risk factors. The median values of NT-proBNP were 600 [280–1930] pg/mL and 0.52 mg/dL [0.16–1.6] for troponin, respectively. Mean values of GCS were −11.6 ± 5.1% and of GWI were 927 ± 403 mmHg%. We analysed the ROC curves of troponin and NT-proBNP to predict values below the median of −10% for GCS and of 937mmHg% for GWI (Fig.1). We found that troponin values > 0.612 mg/dL (AUC 0.674, 95% CI 0.541 to 0.790, p = 0.014, Se 66%, Sp 71%) and NT-proBNP values > 715 pg/mL (AUC 0.678, 95 %CI 0.545 to 0.793, p = 0.0117, Se 59%, Sp 74%) were able to predict more impaired GWI. Interestingly, only troponin values > 0.315 mg/dL, a threshold that was lower than in the case of GWI, were able to predict more impaired GCS (AUC 0.755, 95% CI 0.627 to 0.857, p<0.0001, Se 91%, Sp 58%). Conclusion High sensitive troponin and NT-proBNP may indicate more impaired myocardial mechanics after STEMI. Both GCS and GWI, a parameter integrating strain and afterload, may provide additional information In the early stages of remodeling following MI.