Feasibility of right ventricular longitudinal systolic function evaluation with transthoracic echocardiographic indices derived from tricuspid annular motion: a preliminary study in acute respiratory distress syndrome.

INTRODUCTION: Assessment of right ventricular (RV) function in patients with acute respiratory distress syndrome (ARDS) remains challenging. Transthoracic echocardiographic (TTE) indices based on longitudinal systolic RV function are now considered as a reliable evaluation of RV function. We investigated feasibility of two methods in ARDS patients.
METHODS: Prospective observational study. TTE was performed after 12-36 hours of mechanical ventilation. Feasibility of tricuspid annular motion (S(t) ), tricuspid annular plane systolic excursion (TAPSE) was compared to usual two-dimensional (2D) study: fractional area change (RV(FAC) ) and ratio of right to left ventricular end-diastolic area (RVEDA/LVEDA).
RESULTS: Fifty patients were investigated, with TTE possible in all but two patients. Feasibility was 62% for RV(FAC), 72% for RVEDA/LVEDA, and 96% for TAPSE and S(t). RV dilatation (RVEDA/LVEDA ≥ 0.60) was found in 16 patients, including 4 patients with acute cor pulmonale. A longitudinal RV dysfunction (TAPSE < 12 mm or S(t) < 11.5 cm/sec) was suspected in 30% of patients. Relation between both longitudinal indices was modest (r(2) = 0.36, P < 0.001). TAPSE (but not S(t) ) was found poorly related to RV(FAC) (r(2) = 0.27, P = 0.03). Both indices were related to LV function (S(t) : r(2) = 0.27, TAPSE: r(2) = 0.17, both P < 0.05).
CONCLUSION: Despite a superior feasibility than 2D study, our results suggest that both indices may not bring identical information to echo study. TAPSE may be more adapted to ICU use than S(t) . Both should be further investigated in terms of analysis of RV function and ventricular interdependence. Their relations with LV function may limit their use as sole markers of RV function in this population.