HMGB1 as a predictor of infarct transmurality and functional recovery in patients with myocardial infarction.

OBJECTIVES: High-mobility group box 1 (HMGB1) protein is an innate danger signal for the initiation of host defence and tissue repair. The aim of this study was to analyse serum HMGB1 concentration and its correlation with infarct transmurality and functional recovery in patients with ST-elevation (STEMI) and non-ST-elevation myocardial infarction (NSTEMI). DESIGN: We prospectively examined patients with first-time STEMI (n = 46) or NSTEMI (n = 49), treated according to current guidelines. Contrast-enhanced cardiac magnetic resonance imaging was performed 2-4 days after infarction for the estimation of infarct transmurality and was repeated after 6 months for the estimation of residual left ventricular function. HMGB1 was measured 2-4 days after infarction. RESULTS: High-mobility group box 1 concentration was related to infarct size and to residual ejection fraction in patients with STEMI (r(2) = 0.81 and r(2) =0.40, respectively, P < 0.001 for both) and NSTEMI (r(2) = 0.74 and r(2) = 0.25, respectively, P < 0.001 for both). Receiver operating characteristic (ROC) curve-derived cut-off values of 6.2 and 5.9 ng mL(-1) for patients with STEMI and NSTEMI, respectively, were predictive of infarct transmurality greater than 75% (STEMI: area under the curve (AUC) = 0.93, standard error (SE) = 0.04, 95% confidence interval (CI) = 0.81-0.98; NSTEMI: AUC = 0.96, SE = 0.04, 95% CI = 0.86-0.99). HMGB1 cut-off values of 7.2 and 6.4 ng mL(-1) for patients with STEMI and NSTEMI, respectively, were predictive of residual ejection fraction 6 months after myocardial infarction (MI) (STEMI: AUC = 0.81, SE = 0.07, 95% CI = 0.66-0.91; NSTEMI: AUC = 0.81, SE = 0.09, 95% CI = 0.68-0.91). CONCLUSION: High-mobility group box 1 serum levels represent a highly valuable surrogate marker for infarct transmurality and for the prediction of residual left ventricular function after MI.

Strain-encoded cardiac magnetic resonance for the evaluation of chronic allograft vasculopathy in transplant recipients.

The aim of our study was to investigate the ability of Strain-Encoded magnetic resonance imaging (MRI) to detect cardiac allograft vasculopathy (CAV) in heart transplantation (HTx)-recipients. In consecutive subjects (n = 69), who underwent cardiac catheterization, MRI was performed for quantification of myocardial strain and perfusion reserve. Based on angiographic findings subjects were classified: group A including patients with normal vessels; group B, patients with stenosis <50%; and group C, patients with severe CAV (stenosis >or= 50%). Significant correlations were observed between myocardial perfusion reserve with peak systolic strain (r =-0.53, p < 0.001) and with mean diastolic strain rate (r = 0.82, p < 0.001). Peak systolic strain and strain rate were significantly reduced only in group C, while mean diastolic strain rate and myocardial perfusion reserve were already reduced in group B and A. Myocardial perfusion reserve and mean diastolic strain rate had higher accuracy for the detection of CAV (AUC = 0.95, 95% CI = 0.87-0.99 and AUC = 0.93, 95% CI = 0.84-0.98, respectively) and followed peak systolic strain and strain rate (AUC = 0.80, 95% CI = 0.69-0.89 and AUC = 0.78, 95% CI = 0.67-0.87, respectively). Besides the quantification of myocardial perfusion, the estimation of the diastolic strain rate is a useful parameter for CAV assessment. In combination with the clinical evaluation, these parameters may be effective tools for the routine surveillance of HTx-recipients.