Date Published: June 20, 2019
Publisher: Public Library of Science
Author(s): Misato Chimura, Shinichiro Yamada, Yasuyo Taniguchi, Yoshinori Yasaka, Hiroya Kawai, Vincenzo Lionetti.
Late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is limited in its ability to detect diffuse interstitial fibrosis, which is commonly found in idiopathic dilated cardiomyopathy (DCM). On the other hand, Washout rate (WR) by cardiac 123I- metaiodobenzylguanidine (123I-MIBG) scintigraphy which evaluates cardiac sympathetic nervous function, is a useful tool for predicting the prognosis in DCM. We investigated the predictive value of the combination of two different types of examinations, LGE on CMR and WR by 123I-MIBG scintigraphy for outcomes in DCM compared with LGE alone. One-hundred forty-eight DCM patients underwent CMR and 123I-MIBG scintigraphy. Patients were divided into 4 groups according to the presence or absence of LGE and WR cut-off value of 45% for predicting prognosis based on receiver operating characteristic curve analysis. Cardiac deaths, re-hospitalization for heart failure, implantation of a left ventricular assist device, and life-threatening ventricular arrhythmias were defined as clinical events. Forty-two DCM patients reached the clinical events during the median follow-up for 9.1 years (interquartile range, 8.0–9.2 years).Multivariable Cox regression analysis identified WR≥45%+LGE positive group as an independent predictor of cardiac events (HR 3.18, 95%CI 1.36–7.45, p = 0.008). Notably, there was no significance in the cardiac event-free survival rate between the WR<45%+LGE positive and WR≥45%+LGE negative groups (p = 0.89). The combination of WR by 123I-MIBG scintigraphy and LGE on CMR, which evaluate different type of cardiac deterioration, serves as a stronger predictor of long-term outcomes in DCM patients than LGE alone.
Cardiac magnetic resonance (CMR) is well established as the reference imaging method for the assessment of cardiac anatomy and function . The late gadolinium enhancement (LGE) on CMR by using gadolinium contrast agents, evaluates the myocardial properties and provides the prognostic information about nonischemic cardiomyopathy. However, in LGE on CMR image contrast relies on the difference in signal intensity between normal and fibrotic myocardium, so it is difficult to assess the diffuse interstitial fibrosis which is a characteristic fibrotic pattern of dilated cardiomyopathy (DCM) . Therefore the high risk DCM patients for cardiac events may have been missed in evaluating the presence of LGE alone.
Of 158 DCM patients, 8 with inappropriate CMR images and 2 who were lost to follow-up were excluded, resulting in a final cohort of 148 patients (Fig 1). Cardiac events occurred in 42(28%) DCM patients including 12 cardiac deaths, 2 implantations of LV assist device and 28 re-hospitalizations including 10 life-threatening arrhythmic events during a median follow-up of 9.1 years (interquartile range, 8.0–9.2 years). According to the ROC curve analysis, the WR cut-off value for developing cardiac events was 45%. In response to this result, we divided all 148 DCM patients into 4 groups with the WR cut-off value and the presence or absence of LGE as follows: WR<45%+LGE negative (n = 18), WR≥45%+LGE negative (n = 30), WR<45%+LGE positive (n = 37) and WR ≥45%+LGE positive (n = 63) (Table 1). The main results are as follows: (Ⅰ) The findings of 123I-MIBG scintigraphy, such as delayed H/M and WR are not associated with the LGE status. (Ⅱ) The combination of WR by 123I-MIBG scintigraphy and LGE on CMR in DCM patients is a relevant prognostic marker of long-term cardiac events compared with either the presence of LGE or WR by 123I-MIBG scintigraphy alone. This study is the first clinical study to demonstrate that the combination of WR by 123I-MIBG scintigraphy and LGE on CMR serves as a strong predictor of very long-term outcomes in DCM patients. In DCM patients, the combination of WR by 123I-MIBG scintigraphy and LGE on CMR, which have different properties, might be useful to stratify the future cardiac events than LGE on CMR alone. Source: http://doi.org/10.1371/journal.pone.0217865