Long-Term Outcome and its Predictors in Giant Cell Myocarditis

Abstract Aims There are no studies focusing on prognostic factors in giant cell myocarditis (GCM). We aimed to identify predictors of transplant-free survival in GCM. Methods and results We analysed the details of 46 patients with GCM (31 women, mean age 51 ± 12 years) seen at our hospital since 1991 and followed for the occurrence of cardiac death or transplantation till May 2015. The association of transplant-free survival with patient characteristics, laboratory data on admission, and myocardial histology in the 38 patients diagnosed prior to death or transplantation was examined. Altogether 26 patients died (n = 8) or underwent transplantation (n = 18) a median of 11 months following symptom onset. The 5-year estimate of transplant-free survival was 42% [95% confidence interval (CI) 35–48%]. By Cox regression analysis, the hazard ratio for death or transplantation was 0.87 (95% CI 0.75–0.99) per +5% difference in LVEF, 1.06 (95% CI 1.03–1.10) per + 1000 ng/L difference in NT-proBNP, and 4.57 (95% CI 1.63–11.28) for cardiac troponin-T above the median of 85 ng/L at presentation. The severity of necrosis and fibrosis in myocardial biopsy, graded by the consensus of two cardiac pathologists as none, mild, moderate, or severe, predicted the outcome with a hazard ratio of 7.17 (95% CI 2.29–22.40) for the presence of either necrosis or fibrosis of at least moderate extent. Conclusions In GCM, the probability of transplant-free survival is 42% at 5 years from symptom onset. Markers of myocyte injury and cardiac dysfunction help predict the outcome.