The use of Tricuspid Annular Plane Systolic Excursion and Tissue Doppler Imaging Velocities for the Estimation of Pulmonary Hypertension and Right Ventricular Function in Mechanically Ventilated Patients

Abstract

Right ventricular (RV) function can be seriously compromised due to either left ventricular (LV) failure or severe pulmonary hypertension (PH) and pulmonary vascular dysfunction of extra-cardiac origin, especially in critically ill patients, and can be associated with worse prognosis. Echocardiography in the Intensive Care Unit (ICU) can provide significant information to the caregivers, when confronted with a patient with unexplained hemodynamic instability. However, right ventricular echocardiographic assessment can be a challenge in day-to-day clinical practice in the ICU, mostly because of complex interactions between mechanical ventilation, fluid balance and critical illness per se, whereas right-to-left interdependence can lead to significant hemodynamic collapse in patients with severe respiratory diseases, septic cardiomyopathy or pulmonary embolism. Finally, the complex geometry of the chamber in association with lack of optimal visualization may limit the accuracy of conventional variables, which have bee proven to be reliable in other clinical settings. For the above reasons, novel indices have been adopted for easier, highly reproducible and less variable evaluation of RV function, such as the tricuspid annular plane systolic excursion (TAPSE) and the Tissue Doppler Imaging (TDI) velocities of tricuspid valve. Their accuracy has already been tested in patients with cardiovascular diseases. Nevertheless, their adoption as monitoring tools in critically ill patients under mechanical ventilation remains to be established. In this chapter we will review the different areas of application of TAPSE and TDI velocities and try to discuss their possible potential as accurate and reproducible diagnostic and prognostic techniques in adult critical care.