Assessing Right Ventricle Pulmonary Artery Coupling and Uncoupling Using Echocardiography and Cardiopulmonary Exercise Test in Post Operative TOF Patients

Abstract

Right ventricular-pulmonary arterial (RV-PA) coupling is an important determinant in the development of right ventricular dilatation. RV-PA coupling is defined as the ratio of pulmonary arterial elastance (an index of arterial load) and right ventricular end-systolic elastance (an index of contractility). A retrospective study of postoperative 135 TOF patients who underwent for pulmonary valve replacement was conducted. RV-PA coupling was calculated noninvasively using Ea/Emax (cardiac magnetic resonance) = ventricular end-systolic volume/ventricular systolic volume, equation and patients were divided into coupling and uncoupling group and compared the results on the basis of echocardiography and cardiopulmonary exercise test. Lower tricuspid annular plane systolic excursion, percentage predictive peak VO₂, VE/VCO₂ at anaerobic threshold, (AT), VE/VCO₂ at peak, Minute ventilation, (VE) Volume of Carbondioxide output, (VCO₂) slope, volume of oxygen output (VO₂) work rate (WR) slope, and WR at VO₂ peak were identified as risk factors for uncoupling of RV-PA. In RV-PA coupling combination of echocardiography and cardiopulmonary exercise test revealed the most important modality to identify risk factor and may be useful for therapeutic decision making by identifying patients of especially high risk for inadequate therapy.