Dirk Lossnitzer

Use of cardiovascular magnetic resonance for risk stratification in chronic heart failure: prognostic value of late gadolinium enhancement in patients with non-ischaemic dilated cardiomyopathy

Objective Owing to its variable clinical course, risk stratification is of paramount importance in non-ischaemic dilated cardiomyopathy (DCM). The goal of this study was to investigate the long-term prognostic significance of late gadolinium enhancement (LGE) as detected by contrast-enhanced cardiovascular magnetic resonance (CE-CMR) in patients with DCM. Design Observational cohort study. Setting University hospital. Patients 184 consecutive patients with DCM. Measurements CE-CMR was performed on a 1.5 T clinical scanner. Presence, extent and patterns of LGE were determined by two independent observers. Outcome measures Patients were followed for the composite end point of cardiac death, hospitalisation for decompensated heart failure, or appropriate implantable cardioverter defibrillator discharge for a mean±SEM of 685±30 days. Results LGE was detected in 72/184 patients (39%) and was associated with a lower left ventricular (LV) ejection fraction (31% (20.9–42.2%) vs 44% (33.1–50.9%), p<0.001), higher LV end-diastolic volume index (133 (116–161) ml/m2 vs 109 (92.7–137.6) ml/m2, p<0.001) and higher LV mass (80 (67.1–94.8) g/m2 vs 65.8 (55.2–82.9) g/m2, p<0.001). Patients in whom LGE was present were more likely to experience the composite end point (15/72 vs 6/112, p=0.002). Receiver operating characteristic curve analysis revealed a LGE of >4.4% of LV mass as optimal discriminator for the composite end point. When entered into multivariate Cox regression analysis, LGE retained its independent predictive value, yielding an associated HR of 3.4 (95% CI 1.26 to 9). Conclusion The presence of LGE in this large DCM patient cohort is associated with pronounced LV remodelling, functional impairment and an adverse outcome. Further research is necessary to determine whether these findings will aid the clinical management of DCM patients.

Myocardial delayed enhancement in pulmonary hypertension: pulmonary hemodynamics, right ventricular function, and remodeling.

OBJECTIVE The purpose of this study was to assess predictors of MRI-identified septal delayed enhancement mass at the right ventricular (RV) insertion sites in relation to RV remodeling, altered regional mechanics, and pulmonary hemodynamics in patients with suspected pulmonary hypertension (PH). SUBJECTS AND METHODS Thirty-eight patients with suspected PH were evaluated with right heart catheterization and cardiac MRI. Ten age- and sex-matched healthy volunteers acted as controls for MRI comparison. Septal delayed enhancement mass was quantified at the RV insertions. Systolic septal eccentricity index, global RV function, and remodeling indexes were quantified with cine images. Peak systolic circumferential and longitudinal strain at the sites corresponding to delayed enhancement were measured with conventional tagging and fast strain-encoded MRI acquisition, respectively. RESULTS PH was diagnosed in 32 patients. Delayed enhancement was found in 31 of 32 patients with PH and in one of six patients in whom PH was suspected but proved absent (p = 0.001). No delayed enhancement was found in controls. Delayed enhancement mass correlated with pulmonary hemodynamics, reduced RV function, increased RV remodeling indexes, and reduced eccentricity index. Multiple linear regression analysis showed RV mass index was an independent predictor of total delayed enhancement mass (p = 0.017). Regional analysis showed delayed enhancement mass was associated with reduced longitudinal strain at the basal anterior septal insertion (r = 0.6, p < 0.01). Regression analysis showed that basal longitudinal strain remained an independent predictor of delayed enhancement mass at the basal anterior septal insertion (p = 0.02). CONCLUSION In PH, total delayed enhancement burden at the RV septal insertions is predicted by RV remodeling in response to increased afterload. Local fibrosis mass at the anterior septal insertion is associated with reduced regional longitudinal contractility at the base.

Assessment of myocardial deformation with cardiac magnetic resonance strain imaging improves risk stratification in patients with dilated cardiomyopathy.

AIMS To investigate the prognostic impact of left-ventricular (LV) cardiac magnetic resonance (CMR) deformation imaging in patients with non-ischaemic dilated cardiomyopathy (DCM) compared with late-gadolinium enhancement (LGE) quantification and LV ejection fraction (EF). METHODS AND RESULTS A total of 210 subjects with DCM were examined prospectively with standard CMR including measurement of LGE for quantification of myocardial fibrosis and feature tracking strain imaging for assessment of LV deformation. The predefined primary endpoint, a combination of cardiac death, heart transplantation, and aborted sudden cardiac death, occurred in 26 subjects during the median follow-up period of 5.3 years. LV radial, circumferential, and longitudinal strains were significantly associated with outcome. Using separate multivariate analysis models, global longitudinal strain (average of peak negative strain values) and mean longitudinal strain (negative peak of the mean curve of all segments) were independent prognostic parameters surpassing the value of global and mean LV radial and circumferential strain, as well as NT-proBNP, EF, and LGE mass. A global longitudinal strain greater than -12.5% predicted outcome even in patients with EF < 35% (P < 0.01) and in those with presence of LGE (P < 0.001). Mean longitudinal strain was further investigated using a clinical model with predefined cut-offs (EF < 35%, presence of LGE, NYHA class, mean longitudinal strain greater than -10%). Mean longitudinal strain exhibited an independent prognostic value surpassing that provided by NYHA, EF, and LGE (HR = 5.4, P < 0.01). CONCLUSION LV longitudinal strain assessed with CMR is an independent predictor of survival in DCM and offers incremental information for risk stratification beyond clinical parameters, biomarker, and standard CMR.

Strain-Encoded CMR for the Detection of Inducible Ischemia During Intermediate Stress

OBJECTIVES This study sought to evaluate the diagnostic accuracy of strain-encoded cardiac magnetic resonance (SENC) for the detection of inducible ischemia during intermediate stress. BACKGROUND High-dose dobutamine stress cardiac magnetic resonance (DS-CMR) is a well-established modality for the noninvasive detection of coronary artery disease (CAD). However, the assessment of cine scans relies on the visual interpretation of wall motion, which is subjective, and modalities that can objectively and quantitatively assess the time course of myocardial strain response during stress are lacking. METHODS Stress-induced ischemia was assessed by wall motion analysis and by SENC in 80 patients with suspected or known CAD and in 18 healthy volunteers who underwent DS-CMR in a clinical 1.5-T scanner. Quantitative coronary angiography was used as the standard reference for the presence of CAD (> or =50% diameter stenosis). RESULTS On a patient level, 46 of 80 patients (58%) had CAD, including 20 with single-vessel, 18 with 2-vessel, and 8 with 3-vessel disease. During peak stress, SENC correctly detected ischemia in 45 versus 38 of 46 patients with CAD (7 additional correct findings for SENC), yielding significantly higher sensitivity than cine (98% vs. 83%, p < 0.05). No patients were correctly diagnosed by cine and missed by SENC. During intermediate stress, SENC showed diagnostic value similar to that provided by cine imaging only during peak dobutamine stress (sensitivity of 76% vs. 83%, specificity of 88% vs. 91%, and accuracy of 81% vs. 86%; p = NS for all). Quantification analysis demonstrated that strain rate response is a highly sensitive marker for the detection of inducible ischemia (area under the curve = 0.96; SE = 0.01; 95% confidence interval: 0.93 to 0.99) that precedes the development of inducible wall motion abnormalities and already significantly decreases with moderate 40% to 60% coronary lesions. CONCLUSIONS Using SENC, CAD can be detected during intermediate stress with similar accuracy to that provided by cine only during peak stress. By this approach, patient safety may be improved during diagnostic procedures within lower time spent (Strain-Encoded Cardiac Magnetic Resonance Imaging for Dobutamine Stress Testing; NCT00758654).

Strain-Encoded Cardiac MRI as an Adjunct for Dobutamine Stress Testing Incremental Value to Conventional Wall Motion Analysis

Background—High-dose dobutamine stress MRI is safe and feasible for the diagnosis of coronary artery disease (CAD) in humans. However, the assessment of cine scans relies on the visual interpretation of regional wall motion, which is subjective. Recently, strain-encoded MRI (SENC) has been proposed for the direct color-coded visualization of myocardial strain. The purpose of our study was to compare the diagnostic value of SENC with that provided by conventional wall motion analysis for the detection of inducible ischemia during dobutamine stress MRI. Methods and Results—Stress-induced ischemia was assessed by wall motion analysis and by SENC in 101 patients with suspected or known CAD and in 17 healthy volunteers who underwent dobutamine stress MRI in a clinical 1.5-T scanner. Quantitative coronary angiography deemed as the standard reference for the presence or absence of significant CAD (≥50% diameter stenosis). On a coronary vessel level, SENC detected inducible ischemia in 86 of 101 versus 71 of 101 diseased coronary vessels (P<0.01 versus cine) and showed normal strain response in 189 of 202 versus 194 of 202 vessels with <50% stenosis (P=NS versus cine). On a patient level, SENC detected inducible ischemia in 63 of 64 versus 55 of 64 patients with CAD (P<0.05 versus cine) and showed normal strain response in 32 of 37 versus 34 of 37 patients without CAD (P=NS versus cine). Quantification analysis demonstrated a significant correlation between strain rate reserve and coronary artery stenosis severity (r2=0.56, P<0.001), and a cutoff value of strain rate reserve of 1.64 was deemed as a highly accurate marker for the detection of ≥50% stenosis (area under the curve, 0.96; SE, 0.01; 95% CI, 0.94 to 0.98; P<0.001). Conclusions—The direct color-coded visualization of strain on MR images is a useful adjunct for dobutamine stress MRI, which provides incremental value for the detection of CAD compared with conventional wall motion readings on cine images.Background— High-dose dobutamine stress MRI is safe and feasible for the diagnosis of coronary artery disease (CAD) in humans. However, the assessment of cine scans relies on the visual interpretation of regional wall motion, which is subjective. Recently, strain-encoded MRI (SENC) has been proposed for the direct color-coded visualization of myocardial strain. The purpose of our study was to compare the diagnostic value of SENC with that provided by conventional wall motion analysis for the detection of inducible ischemia during dobutamine stress MRI. Methods and Results— Stress-induced ischemia was assessed by wall motion analysis and by SENC in 101 patients with suspected or known CAD and in 17 healthy volunteers who underwent dobutamine stress MRI in a clinical 1.5-T scanner. Quantitative coronary angiography deemed as the standard reference for the presence or absence of significant CAD (≥50% diameter stenosis). On a coronary vessel level, SENC detected inducible ischemia in 86 of 101 versus 71 of 101 diseased coronary vessels ( P <0.01 versus cine) and showed normal strain response in 189 of 202 versus 194 of 202 vessels with <50% stenosis ( P =NS versus cine). On a patient level, SENC detected inducible ischemia in 63 of 64 versus 55 of 64 patients with CAD ( P <0.05 versus cine) and showed normal strain response in 32 of 37 versus 34 of 37 patients without CAD ( P =NS versus cine). Quantification analysis demonstrated a significant correlation between strain rate reserve and coronary artery stenosis severity ( r 2=0.56, P <0.001), and a cutoff value of strain rate reserve of 1.64 was deemed as a highly accurate marker for the detection of ≥50% stenosis (area under the curve, 0.96; SE, 0.01; 95% CI, 0.94 to 0.98; P <0.001). Conclusions— The direct color-coded visualization of strain on MR images is a useful adjunct for dobutamine stress MRI, which provides incremental value for the detection of CAD compared with conventional wall motion readings on cine images. Received May 3, 2008; accepted December 10, 2008. # CLINICAL PERSPECTIVE {#article-title-2}

Strain-Encoded MRI for Evaluation of Left Ventricular Function and Transmurality in Acute Myocardial Infarction

Background—Strain-encoded imaging (SENC) is a new technique for myocardial deformation analysis in cardiac MRI. The aim of the study was, therefore, to evaluate whether myocardial deformation imaging performed by SENC allows for quantification of regional left ventricular function and is related to transmurality states of infarcted tissue in patients with acute myocardial infarction. Methods and Results—Cardiac MRI was performed in 38 patients with acute myocardial infarction 3±1 days after successful reperfusion using a clinical 1.5-T MRI scanner. Ten healthy volunteers served as controls. SENC is a technique that directly measures peak circumferential strain from long-axis views and peak longitudinal strain from short-axis views. Measurements were obtained for each segment in a modified 17-segment model. Wall motion and infarcted tissue were evaluated semiquantitatively from steady-state free-precession cine sequences and contrast-enhanced MR images and were then related to myocardial strain. Comparison of peak circumferential strain assessed by SENC and MR tagging was performed. In total, 456 segments were analyzed. Peak circumferential and longitudinal strain calculated from SENC images was significantly different in regions defined as normokinetic, hypokinetic, or akinetic (P<0.001). A cutoff peak systolic circumferential strain value of −10% differentiated nontransmural from transmural infarcted myocardium, with a sensitivity of 97% and a specificity of 94%. Strain analysis of SENC and MR tagging correlated well (r=0.76) with narrow limits of agreement (−9.9% to 8.5%). Conclusions—SENC provides rapid and objective quantification of regional myocardial function and allows discrimination between different transmurality states in patients with acute myocardial infarction.

Acupuncture improves exercise tolerance of patients with heart failure: a placebo-controlled pilot study

Background Congestive heart failure (CHF) is a complex clinical syndrome with autonomic dysbalance and increased plasma levels of inflammatory cytokines, which further worsen the syndrome. Experimental data have shown that stimulation of certain acupoints decreases autonomic dysbalance. Objective To test the therapeutic potential of acupuncture for life-threatening diseases such as CHF. Methods 17 stable patients with CHF (New York Heart Association class II–III, ejection fraction <40%) receiving optimised heart failure medication were randomised into a verum acupuncture (VA) and placebo acupuncture (PA) group. Cardiopulmonary function, heart rate variability and quality of life were explored. Results No improvements of the cardiac ejection fraction or peak oxygen uptake were observed, but the ambulated 6 min walk distance was remarkably increased in the VA group (+32±7 m) but not the PA group (−1±11 m; p<0.01). Accordingly, post-exercise recovery after maximal exercise and the VE/VCO2 slope, a marker of ventilatory efficiency, were improved after VA but not PA. Furthermore, heart rate variability increased after VA, but decreased after PA. The ‘general health’ score and ‘body pain’ score of the quality-of-life questionnaire SF-36 tended to be improved after VA. Conclusion Acupuncture may become an additional therapeutic strategy to improve the exercise tolerance of patients with CHF, potentially by improving skeletal muscle function.

Strain-Encoded Magnetic Resonance Imaging for Evaluation of Left Ventricular Function and Transmurality in Acute Myocardial Infarction

Background—Strain-encoded imaging (SENC) is a new technique for myocardial deformation analysis in cardiac MRI. The aim of the study was, therefore, to evaluate whether myocardial deformation imaging performed by SENC allows for quantification of regional left ventricular function and is related to transmurality states of infarcted tissue in patients with acute myocardial infarction. Methods and Results—Cardiac MRI was performed in 38 patients with acute myocardial infarction 3±1 days after successful reperfusion using a clinical 1.5-T MRI scanner. Ten healthy volunteers served as controls. SENC is a technique that directly measures peak circumferential strain from long-axis views and peak longitudinal strain from short-axis views. Measurements were obtained for each segment in a modified 17-segment model. Wall motion and infarcted tissue were evaluated semiquantitatively from steady-state free-precession cine sequences and contrast-enhanced MR images and were then related to myocardial strain. Comparison of peak circumferential strain assessed by SENC and MR tagging was performed. In total, 456 segments were analyzed. Peak circumferential and longitudinal strain calculated from SENC images was significantly different in regions defined as normokinetic, hypokinetic, or akinetic (P<0.001). A cutoff peak systolic circumferential strain value of −10% differentiated nontransmural from transmural infarcted myocardium, with a sensitivity of 97% and a specificity of 94%. Strain analysis of SENC and MR tagging correlated well (r=0.76) with narrow limits of agreement (−9.9% to 8.5%). Conclusions—SENC provides rapid and objective quantification of regional myocardial function and allows discrimination between different transmurality states in patients with acute myocardial infarction.

Increased right ventricular Septomarginal trabeculation mass is a novel marker for pulmonary hypertension: comparison with ventricular mass index and right ventricular mass.

Objective:To prospectively evaluate the cardiac magnetic resonance (MR) imaging-derived measurement of right ventricular (RV) septomarginal trabeculation (SMT) mass as a noninvasive marker for pulmonary hypertension (PH), compared with the ventricular mass index (VMI = RV mass/left ventricular mass) and RV mass. Materials and Methods:A total of 49 patients (60 ± 12 years; 35 female) with suspected PH underwent cardiac MR and right heart catheterization on the same day. Eighteen normal volunteers were also included. The performance of SMT mass, VMI and RV mass measurement, with regard to PH detection, was analyzed using receiver operating characteristic curves. Logistic regression analysis was used to assess the association between SMT mass, RV mass, VMI, and PH. Results:The area under the receiver operating characteristic curve for SMT mass/body surface area (BSA), VMI, and RV mass/BSA in diagnosing the presence or absence of PH was 0.88, 0.87, and 0.73 respectively. In multivariable models, both SMT mass/BSA (P = 0.005, odds ratio: 8.6) and VMI (P = 0. 012, odds ratio: 1.1) were found to be significant, independent predictors of PH. Conclusion:Compared with right heart catheterization measurement, SMT mass and VMI are reproducible and noninvasive MR imaging markers for the diagnosis of PH.

Strain-encoded cardiac MR during high-dose dobutamine stress testing: comparison to cine imaging and to myocardial tagging.

To investigate regional strain response during high‐dose dobutamine stress cardiac magnetic resonance imaging (DS‐CMR) using myocardial tagging and Strain‐Encoded MR (SENC).