Association Between Portal Flow Pulsatility and Right Ventricular Dysfunction in the Postoperative Period of Cardiac Surgery

Overview

Right ventricular dysfunction (RVD) after cardiac surgery is associated with ischemia and myocardial injury. While echocardiographic measures like Tricuspid Annular Plane Systolic Excursion (TAPSE) are frequently used to assess ventricular function, they have limitations in terms of accuracy. The pulmonary artery catheter remains the gold standard for assessing RVD. This dysfunction is associated with an increased risk of both renal and hepatic failure, complications that significantly affect patient outcomes. Doppler ultrasound has emerged as a valuable tool in predicting these complications, particularly in monitoring portal circulation and hepatic perfusion. This study aims to explore the association between portal flow pulsatility and RVD after cardiac surgery.

The postoperative right ventricular dysfunction (RVD) after cardiac surgery has been described since the 1990s. It is associated to various pathophysiological mechanisms, including ischemia from prolonged aortic clamping, cardioplegia defects, myocardial injury, and ischemia-reperfusion phenomena. Many studies have observed reduced right ventricular function intraoperatively through transthoracic echocardiographic parameters like TAPSE, fractional area change, and longitudinal strain. However, accurately assessing RVD is challenging, as these parameters can be affected post-surgery without indicating true ventricular failure. In this context, obtaining reliable and robust invasive hemodynamic measurements is crucial for accurate assessment of RVD. The pulmonary artery catheter (PAC), or Swan-Ganz catheter remains the gold standard, providing precise information on right ventricular systolic and diastolic function, pulmonary artery pressures, left ventricular end-diastolic pressure, venous oxygen saturation, and cardiac output. In cardiac surgery, venous congestion resulting from right ventricular dysfunction is closely associated with increased mortality, leading to renal and hepatic failure. Tools like Doppler ultrasound (of renal, portal, and hepatic veins) can predict renal failure risk. Researchers developed the VEXUS score in 2020 to assess this risk, and recent research found an association between 50% portal flow pulsatility and RVD. However, some aspects remain to be clarified, such as the significant association between portal venous flow pulsatility and altered TAPSE. This prospective study aims to examine the association between portal flow pulsatility and right ventricular dysfunction after cardiac surgery.