CMR Imaging Predicts Death and Other Adverse Events in Suspected Cardiac Sarcoidosis
What is the prognostic significance of myocardial fibrosis on cardiac magnetic resonance (CMR) in patients with suspected cardiac sarcoidosis?
The authors retrospectively reviewed CMR studies from 155 patients at multiple centers, mostly in Germany, with systemic sarcoidosis proven by biopsy or diagnosed with clinical criteria, who were referred for initial evaluation of cardiac involvement. Subjects were categorized as having or not having late gadolinium enhancement (LGE), which may represent fibrosis. Subjects were followed for a median of 2.6 years, with a follow-up rate of 98.7% for the primary endpoint of fatal and potentially fatal events (death from any cause, aborted sudden cardiac death, or appropriate implantable cardioverter-defibrillator [ICD] discharge), and a broader secondary composite endpoint of potentially fatal events and sustained or nonsustained ventricular tachycardia (VT).
LGE was seen in 39/155 patients (25.5%). A total of 12 first fatal and potentially fatal events occurred (3% per year). Twenty subjects experienced the composite of potentially fatal events and VT. The presence of LGE was associated with a 44-fold increase in risk of potentially fatal events (hazard ratio [HR], 44.4; 95% confidence interval, 5.5-358.4). Multivariate Cox proportional hazards regression including the presence of LGE, initial left ventricular ejection fraction (LVEF), initial LV end-diastolic volume, and initial presentation as heart failure demonstrated that LGE was the most powerful predictor of both composite endpoints, with an HR of 31.6 (p = 0.001) for fatal and potentially fatal events and 33.9 for all events (p < 0.001).
The authors concluded that the presence of LGE on CMR is a powerful independent predictor of prognosis in patients with known systemic sarcoidosis and clinical concern for cardiac involvement.
This is the first large multicenter prognostic study of CMR in patients with suspected cardiac involvement of proven systemic sarcoidosis. The study demonstrated that although the absolute event rate for the entire cohort was quite low (3% per year), among those with LGE on CMR imaging, >35% went on to experience a fatal or potentially fatal event. Consequently, these data have important implications for selection of patients who will benefit from ICD therapy. There are a few critical limitations, however. The authors do not report the rate of ICD implantation among those with and without LGE on CMR imaging. It is possible and likely that the rate of ICD implantation was markedly higher among those with LGE given that they had lower LVEF, more heart failure symptoms, and were generally considered higher risk on the basis of prior data. The presence of an ICD may lead to a higher sensitivity for detection of sustained and nonsustained VT. Furthermore, prior randomized trials of defibrillator therapy have demonstrated that many appropriate ICD shocks occur for events, which would not have been fatal. As a result, the HRs reported in this study are likely to be overestimated.
Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure
Keywords: Risk, Myocardial Infarction, Defibrillators, Follow-Up Studies, Shock, Biopsy, Gadolinium, Germany, Hirudins, Tachycardia, Prognosis, Sarcoidosis, Cardiomyopathies, Heart Failure, Recombinant Proteins, Stroke Volume, Ventricular Function, Confidence Intervals, Fibrosis, Magnetic Resonance Spectroscopy
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