Speckle-tracking global longitudinal strain as a predictor of clinical outcomes in patients with idiopathic inflammatory myopathies

Abstract Background Idiopathic inflammatory myopathies (IIM) are systemic immune-mediated diseases that involve the skeletal muscle and several other organ systems, including the heart. Nonetheless, cardiac involvement in IIM is frequent and initially subclinical. Previous studies have demonstrated how speckle-tracking-derived global longitudinal strain (GLS), as a measurement of the subclinical systolic ventricular dysfunction, is significantly lower in IIM compared to healthy controls. Purpose To assess the progression of myocardial deformation in patients with IIM and test GLS as a prognostic marker of death and cardiovascular events. Methods We enrolled all consecutive patients with a diagnosis of IIM sent to our Cardiology Clinic. The diagnosis of definite idiopathic polymyositis or idiopathic dermatomyositis as made according to the Bohan and Peter criteria and confirmed by muscle biopsy. Patients with inclusion body myositis, necrotizing autoimmune myositis, overlap myositis, and juvenile myositis were excluded from our study. All patients underwent full evaluation, including clinical, ecg and echocardiographic assessment as well as GLS calculation both at baseline and follow up appointments. Primary endpoint was a composite of death and cardiovascular events. Results 41 consecutive patients (28 females, 58±15 years) with IIM were consecutively enrolled and followed up for a median of 8 years (4-11 years). During follow-up, a progressive worsening of LVEF (-4%; p=.03) and left GLS (LGLS: +3%; p=.04) was shown, along with an increase in atrial volumes (iLAV: +8 cm2/m2; p=.02; iRAV: +10 cm2/m2; p=0.01) and estimated filling pressures (E/e': +2; p=.01). A left GLS (LGLS) > -16% predicted the composite endpoint with a sensitivity of 80% and a specificity of 67% (AUC 0.74). Estimated survival from the composite endpoint was 85% for the normal LGLS group and 35% for the impaired LGLS group (Figure 1). Right GLS was not significantly associated with the primary endpoint. Conclusions Heart involvement is becoming a major cause of death in patients with myositis. Data reported that subclinical heart involvement, characterized by biochemical and instrumental modifications, is estimated to affect around 70% of patients with myositis. Cardiac involvement in IIM is often subclinical in the early stages of the disease. GLS has been proven to be an effective tool to predict heart disease. Our results show that GLS worsens over time and can be used as a possible predictor of death and cardiovascular events in this population.Figure 1