DS-MRI can accurately identify patients who are at increased risk for cardiac death and myocardial infarction, separating them from those with normal findings, who have very low risk for future cardiac events. (Prognostic Value of High Dose Dobutamine Stress Magnetic Resonance Imaging; NCT00837005).

Abstract. Andrassy M, Volz HC, Riedle N, Gitsioudis G, Seidel C, Laohachewin D, Zankl AR, Kaya Z, Bierhaus A, Giannitsis E, Katus HA, Korosoglou G (University of Heidelberg, Heidelberg, Germany). HMGB1 as a predictor of infarct transmurality and functional recovery in patients with myocardial infarction. J Intern Med 2011; 270: 245-253.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 firsttime 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) curvederived 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. 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.

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 ≥ 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.

Purpose: To investigate regional strain response during high-dose dobutamine stress cardiac magnetic resonance imaging (DS-CMR) using myocardial tagging and StrainEncoded MR (SENC). Materials and Methods:Stress induced ischemia was assessed by wall motion analysis, by tagged CMR and by SENC in 65 patients with suspected or known CAD who underwent DS-CMR in a clinical 1.5 Tesla scanner. Coronary angiography deemed as the standard reference for the presence or absence of CAD (Ն50% diameter stenosis) in all patients.Results: SENC and conventional tagging detected abnormal strain response in six and five additional patients, respectively, who were missed by cine images and proved to have CAD by angiography (P Ͻ 0.05 for SENC versus cine, P ϭ 0.06 for tagging versus cine and p ϭ NS for SENC versus tagging). On a per-vessel level, wall motion analysis on cine images showed high specificity (95%) but moderate sensitivity (70%) for the detection of CAD. Tagging and SENC yielded significantly higher sensitivity of 81% and 89%, respectively (P Ͻ 0.05 for tagging and P Ͻ 0.01 for SENC versus wall motion analysis, and p ϭ NS for SENC versus tagging), while specificity was equally high (96% and 94%, respectively, P ϭ NS for all). Conclusion:Both the direct color-coded visualization of strain on CMR images and the generation of additional visual markers within the myocardium with tagged CMR represent useful adjuncts for DS-CMR, which may provide incremental value for the detection of CAD in humans. HIGH-DOSE DOBUTAMINE stress cardiac magnetic resonance (DS-CMR) is a sensitive modality for the diagnosis of inducible ischemia in patients with suspected or known coronary artery disease (CAD) (1-4). Cine-MR sequences allow the delineation of the endocardial borders and offer the reproducible assessment of left ventricular wall thickening. With these sequences regional wall motion abnormalities (WMA), which precede the development of ECG changes and of anginal symptoms (5) in the ischemic cascade, can readily be detected based on the evaluation of the movement and thickening of the myocardium (2-4). However, the assessment of cine images relies on the visual assessment of myocardial motion by the human eye, which is subjective and depends on the experience of the readers.CMR tagging provides estimation of regional myocardial function with high accuracy (6 -8). In previous clinical trials, myocardial tagging was shown to detect myocardial viability in combination with lowdose dobutamine stimulation (9 -11). However, little information exists on the ability of this technique to detect inducible ischemia during high dose dobutamine stress testing. Furthermore, Strain-Encoded MR (SENC) has been recently proposed for the objective color-coded evaluation of circumferential and longitudinal myocardial strain. The ability of SENC to quantify myocardial strain has been validated in experimental and in clinical settings (12-15) and this technique favorably compares over more conventional CMR tagging sequences in terms of temporal resolution...

Strain-encoded MRI aids the accurate identification of patients at high risk for future cardiac events and revascularization procedures, beyond the assessment of conventional atherogenic risk factors and resting or inducible WMA on cine images. (Strain-Encoded Cardiac Magnetic Resonance Imaging as an Adjunct for Dobutamine Stress Testing; NCT00758654).