Ventricular diastolic stiffness predicts perioperative morbidity and duration of pleural effusions after the Fontan operation

Background-We validated the clinical relevance of ventricular stiffness by examining surgical morbidity in children with univentricular hearts undergoing Fontan operation. We hypothesized that ventricular stiffness affects Fontan morbidity, particularly duration of pleural effusions. Methods and Results-Sixteen children with right ventricular (RV) (n=11) or left ventricular (LV) (n=5) dominance were studied intraoperatively at a median age of 3.3 years (1.8 to 5.1). Transesophageal long-axis echocardiograms and ventricular pressure by micromanometer provided end-diastolic pressure (P) area (A) relations during initiation and conclusion of cardiopulmonary bypass. Curve fitting to the equation P=alpha e(beta A) defined the ventricular stiffness constant, beta. Changes in beta and clinical correlations were examined. Ventricular stiffness increased after bypass in patients with complete pre-bypass and post-bypass data (n=11, P=0.023, mixed models methodology). Pre-bypass beta correlated well with duration of chest tube (CT) drainage (r=0.90, n=16), net perioperative fluid balance (r=0.71, n=14), and length of stay (LOS) (r=0.81, n=16). CT duration and LOS also correlated significantly with post-bypass beta (r=0.77 for both, n=11), but insignificantly with preoperative catheterization pressures. Conclusions-Intraoperative beta predicts duration of CT drainage, net perioperative fluid balance, and LOS after the Fontan operation. These observations could improve risk stratification and clinical management of children at high-risk undergoing the Fontan operation.