Clinical utility of single ventricular stroke work index for predicting prognosis in patients with functional single...

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 yr after the catheterization, event-free survival, and mortality. We also investigated the relationships between SVSWI and patients' hemodynamic parameters 1 yr after Fontan completion. Forty-three patients were enrolled and divided into a high-SVSWI group (group H, SVSWI > 54.0 g·m/m², n = 23) and a low-SVSWI group (group L, SVSWI < 54.0 g·m/m², 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.NEW & NOTEWORTHY We defined a single ventricular stroke work index (SVSWI) specifically to evaluate single-ventricle physiology, and investigated its usefulness as a prognostic predictor in patients with single-ventricle physiology. We demonstrated that the pre-Glenn SVSWI can predict the completion of Fontan surgery, survival, and avoidance of cardiac events. These findings are supported by our data showing that the pre-Glenn SVSWI is correlated with parameters associated with single ventricular function after Fontan completion.