Troponin elevation reflects disease severity rather than cardiac injury or dysfunction in mechanically ventilated COVID-19 ARDS patients.

BACKGROUND: Cardiac troponin elevation is common in severe COVID-19 and acute respiratory distress syndrome (ARDS). OBJECTIVES: To examine the association of elevated troponin I (TnI) with cardiac function, disease severity, and survival in mechanically ventilated (MV) COVID-19 ARDS patients. METHODS: We retrospectively analyzed MV patients with COVID-19 ARDS and elevated TnI (>0.04 ng/mL) who underwent transthoracic echocardiography within 48 h of ICU admission for a previous study. Left ventricular function was assessed by left ventricular ejection fraction (LVEF), global longitudinal strain (LVGLS), and lateral mitral annular systolic velocity (LV S'). Right ventricular function and afterload were evaluated using tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP). Disease severity was assessed using APACHE II and SOFA scores. Associations of TnI with echocardiographic indices, severity scores, and survival were analyzed. RESULTS: Ninety-four patients were included. Troponin correlated positively with APACHE II (r = 0.415, p < 0.0001) and SOFA (r = 0.232, p = 0.046), and inversely with ICU survival (r = -0.506, p < 0.0001), but not with LVEF, LVGLS, LV S', TAPSE, or PASP. ICU and 28-day survival did not differ between patients with LVEF <40% and those with LVEF ≥40%. Severity scores and troponin levels were similar between groups. In patients with LVEF <40%, LVGLS showed a moderate inverse correlation with troponin (r = -0.553, p = 0.032). CONCLUSIONS: In MV COVID-19 ARDS patients, elevated troponin is associated disease severity and poorer ICU survival rather than global systolic dysfunction. In patients with severe LV impairment, troponin may remain a marker of myocardial injury.