Clinical Utility of Single Ventricular Stroke Work Index for Predicting Prognosis in Patients with Functional Single Ventricle

Stroke work of the ventricle is a parameter that integrates ventricular systolic and diastolic function. However, its clinical application in single-ventricle physiology has not been established. Thus, we defined a single ventricular stroke work index (SVSWI) and evaluated its ability to predict the prognosis of patients with single-ventricle physiology. On the basis of the results of cardiac catheterization before the Glenn procedure, we calculated the SVSWI using the following equation: SVSWI = (systemic blood flow + pulmonary blood flow)/heart rate/body surface area × (mean aortic pressure - pulmonary arterial wedge pressure) × 0.0136. We evaluated the ability of the SVSWI to predict the rate of patients completing the Fontan procedure within 2 years after the catheterization, event-free survival, and mortality. We also investigated the relationships between SVSWI and patients’ hemodynamic parameters 1 year after Fontan completion. Forty-three patients were enrolled and divided into a high-SVSWI group (Group H, SVSWI > 54.0 g·m/m 2 , N = 23) and a low-SVSWI group (Group L, SVSWI < 54.0 g·m/m 2 , N = 20). The rate of Fontan completion was significantly greater in Group H than in Group L (100% vs. 80%, p = 0.0243). Survival and event-free survival were also significantly greater in Group H (p = 0.0248 and 0.0050, respectively). The pre-Glenn SVSWI was positively correlated with cardiac output, mean blood pressure, venous oxygen saturation, and SVSWI after the Fontan procedure. In conclusion, the SVSWI is a valuable prognostic predictor for patients with single-ventricle physiology regardless of the underlying heart disease or ventricular morphology.