Prediction of hemodynamics after atrial septal defect closure using a framework of circulatory equilibrium in dogs

Abstract

In patients with heart failure, atrial septal defect (ASD) closure has a risk to induce life-threatening acute pulmonary edema. The objective of this study was to develope a novel framework for quantitative prediction of hemodynamics after ASD closure. The generalized circulatory equilibrium comprises right and left cardiac output (CO) curves, and pulmonary and systemic venous return surfaces. We incorporated ASD into the framework of circulatory equilibrium by representing ASD shunt flow (QASD) by the difference between pulmonary flow (QP) and systemic flow (QS). To examine the accuracy of prediction, we created ASD in six dogs. Four weeks after ASD creation, we measured left atrial pressure (PLA), right atrial pressure (PRA), QP and Qs before and after ASD balloon occlusion. We then predicted post-occlusion hemodynamics from measured pre-occlusion hemodynamics. Finally, we numerically simulated hemodynamics under various ASD diameters while changing left and right ventricular function. Predicted post-occlusion PLA, PRA and QS from pre-occlusion hemodynamics matched well with those measured [PLA: coefficient of determination (r2) = 0.96, standard error of estimate (SEE) = 0.89 mmHg, PRA: r2 = 0.98, SEE = 0.26 mmHg, QS: r2 = 0.97, SEE = 5.6 ml·min-1·kg-1]. A simulation study demonstrated that ASD closure increases the risk of pulmonary edema in patients with impaired left ventricular function with normal right ventricular function indicating the importance of evaluation for the balance between right and left ventricular function. ASD shunt incorporated into the generalized circulatory equilibrium accurately predicted hemodynamics after ASD closure, which would facilitate safety management of ASD closure.