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Abstract

We read the letter by Rerkpattanapipat et al and thank them for their comments regarding our study “diagnostic accuracy of cardiac magnetic resonance imaging in the evaluation of newly diagnosed heart failure with reduced left ventricular ejection fraction.” 1 Won E. Donnino R. Srichai M.B. Sedlis S.P. Feit F. Rolnitzky L. Miller L.H. Iqbal S.N. Axel L. Nguyen B. Slater J. Shah B. Diagnostic accuracy of cardiac magnetic resonance imaging in the evaluation of newly diagnosed heart failure with reduced left ventricular ejection fraction. Am J Cardiol. 2015; 116: 1082-1087 Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar First, we agree that patients with an elevated troponin are at greater risk than those without elevated cardiac biomarkers. However, patients with newly diagnosed heart failure frequently have mildly elevated troponin levels, regardless of the origin. 2 Kociol R.D. Pang P.S. Gheorghiade M. Fonarow G.C. O'Connor C.M. Felker G.M. Troponin elevation in heart failure prevalence, mechanisms, and clinical implications. J Am Coll Cardiol. 2010; 56: 1071-1078 Abstract Full Text Full Text PDF PubMed Scopus (333) Google Scholar Although 70% of our study population did have elevated troponins, the median and interquartile range was 0.21 ng/ml (0.03 to 2.93). Second, owing to the limited use of 3.0 T magnetic resonance imaging (MRI) systems for cardiac imaging at our institution during the study period, the vast majority of the MRIs in our study were acquired using 1.5 T systems. Further studies to determine if increased magnetic field strength, and/or other advancements in MRI technology, may improve the diagnostic performance of MRI in heart failure are warranted. Similarly, although the evaluation of the role of stress cardiac MRI (CMR) was beyond the scope of the present study, we agree that stress CMR may indeed provide additional value but at an increased cost, length of study time, and resources. Third, we agree that the combination of ischemic patterns on late gadolinium enhancement (LGE) and regional wall motion abnormality from cine images may not provide enough confidence to defer invasive coronary angiography. However, we also demonstrated that the absence of an ischemic pattern on LGE, together with no regional wall motion abnormalities on cine images, provides a specificity of 94% for the diagnosis of a nonischemic cardiomyopathy (NIC). 1 Won E. Donnino R. Srichai M.B. Sedlis S.P. Feit F. Rolnitzky L. Miller L.H. Iqbal S.N. Axel L. Nguyen B. Slater J. Shah B. Diagnostic accuracy of cardiac magnetic resonance imaging in the evaluation of newly diagnosed heart failure with reduced left ventricular ejection fraction. Am J Cardiol. 2015; 116: 1082-1087 Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar Additionally, the presence of midwall and/or subepicardial LGE alone provided 97% specificity for the diagnosis of NIC. 1 Won E. Donnino R. Srichai M.B. Sedlis S.P. Feit F. Rolnitzky L. Miller L.H. Iqbal S.N. Axel L. Nguyen B. Slater J. Shah B. Diagnostic accuracy of cardiac magnetic resonance imaging in the evaluation of newly diagnosed heart failure with reduced left ventricular ejection fraction. Am J Cardiol. 2015; 116: 1082-1087 Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar Thus, we concluded that a CMR pattern suggestive of NIC may call for a consideration for deferring invasive coronary angiography. Although an alternative noninvasive strategy such as coronary computed tomographic angiography (CCTA) may be considered, there are several clinical situations in which CCTA is not an ideal option. For example, patients with heart failure often have a tachycardia at rest, which may preclude adequate image quality on CCTA; some patients have a significant amount of coronary calcification which also limits CCTA accuracy; and patients with mild-to-moderate renal insufficiency are at increased risk for contrast nephropathy from iodinated contrast necessary for CCTA. In such cases, CMR would likely be the preferred noninvasive diagnostic method. Nonetheless, we agree that CCTA is an important technology that may play a significant role in the evaluation of cardiomyopathy, and further study is indeed needed to define the best cost-effective imaging strategy in this population. The Role of Cardiac Imaging in the Evaluation of Newly Diagnosed Heart FailureAmerican Journal of CardiologyVol. 117Issue 3PreviewWon et al,1 reported the potential utility of findings on late gadolinium enhancement (LGE) and cine images acquired with cardiac magnetic resonance imaging to differentiate ischemic from nonischemic cardiomyopathy in patients with newly diagnosed heart failure with reduced left ventricular ejection fraction. There are few comments on the method and finding of this study. First, 70% of study population had elevated troponin, which indicated high-risk group of patients with heart failure who might require more aggressive or invasive strategy than those without elevated troponin. Full-Text PDF