P1392 Association of iron deficiency with left ventricular longitudinal function abnormalities in patients with acute myocarditis

Abstract

Background Recent evidence suggests that iron depletion may be involved in the pathophysiology of acute myocarditis (MCD), however no data on the contribution of this mechanism to the MCD-associated cardiac performance abnormalities are available. The decrease in longitudinal deformation is an early manifestation of left ventricular (LV) dysfunction. Nonetheless, global longitudinal strain (GLS) is afterload-dependent, and the estimation of myocardial work correcting GLS for changes in systolic blood pressure may permit a more adequate assessment of LV contractility. Aim We sought to investigate the association between iron status and LV function in patients with MCD. Methods We prospectively included 30 patients (age 32 ± 8 years; 97% male) hospitalized for acute MCD in a tertiary cardiology center. MCD was diagnosed based on the following criteria: 1) new onset symptoms suggestive of myocarditis (exercise intolerance, dyspnea, palpitations or chest pain), 2) elevated high sensitivity cardiac troponin I (hscTnI), 3) exclusion of obstructive coronary artery disease, 4) confirmation of myocardial oedema based on T2 mapping in cardiac magnetic resonance. On admission, each participant underwent echocardiography with LV strain and myocardial work (global work index [GWI], global constructive work [GCW], global wasted work [GWW], global work efficiency [GWE]) analysis, and laboratory assessment including the iron status markers: ferritin and transferrin saturation (TSAT). Iron deficiency (ID) was defined as transferrin saturation (TSAT) <20%; we did not use serum transferrin to categorize iron status because of the strong association of this marker with acute inflammation, which might affect the interpretation of its values. Results ID was found in 16 (53%) enrollees. Patients with reduced TSAT demonstrated lower GCW and GWI than their peers with normal TSAT (Table). No significant between-group differences were found for GLS, LV ejection fraction, early diastolic tissue velocity (e’) and E/e’ ratio. Both subsets did not significantly differ with respect to hemoglobin, creatinine, NT-proBNP, hscTnI and CRP. Both GWI and GCW significantly correlated with TSAT (r = 0.39, p = 0.03, and r = 0.37, p = 0.04, respectively). In multivariable analysis, after adjustment for patient age, body mass index, creatinine, hscTnI and CRP, TSAT was an independent predictor of GWI (beta = 0.40; p = 0.02) and GCW (beta = 0.38; p = 0.02). Conclusion In patients with MCD, ID defined as low TSAT is associated with a worse LV longitudinal performance as assessed by GCW and GWI, which might suggest a role of this pathophysiological pathway in the development of cardiac dysfunction. Myocardial work parameters seem to outperform GLS in diagnosing LV functional impairment in this clinical setting. Abstract P1392 Figure.