High-sensitive cardiac troponin T in patients with idiopathic inflammatory myopathies

Introduction Patients with idiopathic inflammatory myopathies (IIM) may have positive blood tests of cardiac troponin in absence of clinically detected cardiac disease. This situation is more common using high-sensitive cardiac troponin T (hs-cTnT) but there is limited information of the expected results according to type of IIM and prognostic value of this test in this group of patients. Methods Prospective study with 32 healthy controls and 61 patients with IIM without known cardiac condition. These patients with IIM were followed for 25 months. High-sensitive cardiac troponin T (Roche Elecsys hs-cTnT) was measured at baseline in both groups and a value of 14 pg/ml was the percentile 99th and considered the upper limit of normality (ULN). Results The median value of hs-cTnT was higher in patients with myopathies [12.0 (5.0; 35.0) vs. 5.0 (4.0; 6.2) P< 0.001] and the frequency of abnormal values were also more common in patients with IIM compared to controls (45.9% vs 6.2%, p<0.001). The frequency varied according to the type of myositis: Inclusion Body Myosytis (75%), Polymyositis (66.7%) , Dermatomyositis (42.1%) and Antisynthetase syndrome (38.5%). In terms of magnitude, 57% had mild elevations (1 to 3 x ULN) while 11% had levels 3 to 5 times ULN and 32% had troponin values > 5x ULN (Figure 1). Among patients with IIM, elevated levels of hs-cTnT were not associated with left ventricle global longitudinal strain < 18% or lower ejection fraction and was not associated with cardiovascular events during 25 months of follow-up (Figure 2). Conclusion Abnormal values of high-sensitive cardiac troponin T are common in patients with idiopathic inflammatory myopathies including levels similar to myocardial infaction. This elevation was not associated with echocardiographic abnormalities or cardiovascular events in patients with IIM.Figure 1Figure 2