Assessment of global longitudinal strain and plasma natriuretic peptide in patients with asymptomatic left ventricular dysfunction

Objective    The purpose of this study was to investigate the association between global longitudinal strain (GLS) and plasma NT-proBNP for predicting left ventricular (LV) performance in asymptomatic patients after acute myocardial infarction (AMI). Material and methods    We prospectively included patients with diagnosis of AMI without clinical signs and symptoms of heart failure (HF) and followed these patients for 6 mos. Baseline echocardiography was performed at admission, and follow-up echocardiography was performed after 6 mos. A normal GLS was defined as having an absolute value of ≥16 %. According to the baseline GLS, participants were divided into two groups and compared. In all participants, blood samples of plasma NT-proBNP were obtained at admission, before discharge, and 6 mo after discharge. Results    The study population was consisted of 98 participants, of which 80 (81.6 %) were males, and the mean age was 56.0±9.3 years. Baseline echocardiography showed that most of the participants (60, 61.2 %) had abnormal GLS<16 %, whereas 38 (38.8 %) participants had normal or borderline GLS ≥16 %. Compared with the normal GLS group, participants with abnormal GLS had higher GRACE score, higher troponin I concentration, lower systolic blood pressure, lower mean LV ejection fraction, and decreased LV diastolic function. At 6‑mo follow-up, only LV systolic function remained significantly different between the two groups. Compared to baseline, there was a significant improvement of GLS in the abnormal GLS group at 6‑mo follow-up (p=0.04). Prevalence of complications after AMI was significantly higher in this group. There were significant differences between baseline and discharge NT-proBNP concentrations between the two groups (p<0.05). In the abnormal GLS group, there were significant correlations between baseline and discharge NT-proBNP concentrations with baseline LV systolic function. Discharge NT-proBNP concentration also correlated significantly with 6‑mo follow-up GLS. For determining the effect of baseline GLS abnormality, the areas under the ROC curve for baseline and discharge NT-proBNP concentrations were 0.73 (95 % CI 0.60–0.85, p=0.001) and 0.77 (95 % CI 0.66–0.87, p<0.001), respectively. Regarding early prediction of follow-up GLS abnormality, the area under the ROC curve for discharge NT-proBNP concentration was significantly higher 0.70 (95 % CI 0.55–0.84, p=0.016). The optimum cut-off value of discharge NT-pro-BNP was 688.5 pg / ml, with 72.4 % sensitivity and 65.4 % specificity to predict 6‑mon GLS abnormality following acute myocardial infarction. Conclusion    The main finding of this study is that impaired LV GLS is associated with elevated plasma concentrations of NT-proBNP in post-AMI patients. Pre-discharge NT-proBNP concentration combined with impaired initial GLS could predict worsening LV systolic function over time in asymptomatic post-AMI patients.