Longitudinal Validation of Right Ventricular Pressure Monitoring for the Assessment of Right Ventricular Systolic Dysfunction in a Large Animal Ischemic Model

Abstract

CONTEXT: Right ventricular (RV) dysfunction is a major cause of morbidity and mortality in intensive care and cardiac surgery. Early detection of RV dysfunction may be facilitated by continuous monitoring of RV waveform obtained from a pulmonary artery catheter. The objective is to evaluate the extent to which RV pressure monitoring can detect changes in RV systolic performance assess by RV end-systolic elastance (E es ) following the development of an acute RV ischemic in a porcine model. HYPOTHESIS:RV pressure monitoring can detect changes in RV systolic performance assess by RV E es following the development of an acute RV ischemic model. METHODS AND MODELS:Acute ischemic RV dysfunction was induced by progressive embolization of microsphere in the right coronary artery to mimic RV dysfunction clinically experienced during cardiopulmonary bypass separation caused by air microemboli. RV hemodynamic performance was assessed using RV pressure waveform-derived parameters and RV E es obtained using a conductance catheter during inferior vena cava occlusions. RESULTS:Acute ischemia resulted in a significant reduction in RV E es from 0.26 mm Hg/mL (interquartile range, 0.16-0.32 mm Hg/mL) to 0.14 mm Hg/mL (0.11-0.19 mm Hg/mL; p < 0.010), cardiac output from 6.3 L/min (5.7-7 L/min) to 4.5 (3.9-5.2 L/min; p = 0.007), mean systemic arterial pressure from 72 mm Hg (66-74 mm Hg) to 51 mm Hg (46-56 mm Hg; p < 0.001), and mixed venous oxygen saturation from 65% (57-72%) to 41% (35-45%; p < 0.001). Linear mixed-effect model analysis was used to assess the relationship between E es and RV pressure-derived parameters. The reduction in RV E es best correlated with a reduction in RV maximum first derivative of pressure during isovolumetric contraction (dP/dt max ) and single-beat RV E es . Adjusting RV dP/dt max for heart rate resulted in an improved surrogate of RV E es . INTERPRETATION AND CONCLUSIONS:Stepwise decreases in RV E es during acute ischemic RV dysfunction were accurately tracked by RV dP/dt max derived from the RV pressure waveform.