[I-AEPCYIA-02] Utility of the single ventricular stroke work index for predicting the prognosis of patients with functional single-ventricle physiology
Background: The stroke work index (SWI) has been shown to reflect ventricular workload and considers both ventricular systolic and diastolic function. In this study, we evaluated the utility of single ventricular SWI (SVSWI) for predicting the prognosis of single-ventricle patients.Methods: This was a retrospective cohort study including 36 single-ventricle patients who underwent Blalock-Taussig shunt or pulmonary artery banding. Based on the results of cardiac catheterization before the Glenn procedure, we calculated SVSWI using the following equation: SVSWI = stroke volume of the single ventricle/body surface area × (mean aortic pressure - atrial pressure) × 0.0136. Using Fick’s method, stroke volume was calculated based on the sum of systemic and pulmonary blood flow. We evaluated the utility of SVSWI for predicting the rate of reaching Fontan completion within 2 years after catheterization and survival.Results: The mean age at catheterization was 0.53 ± 0.46 years. The patients were divided into a high SVSWI group (Group H, SVSWI>60, N=19) and a low SVSWI group (Group L, SVSWI<60, N=17). The rate of reaching Fontan completion was significantly higher in Group H than in Group L (100% vs. 76%, p=0.0242). The survival rate was also significantly higher in Group H (p=0.0081). The 5-year survival rates for Group H and L were 100% and 81%, and the 10-year survival rates were 100% and 65%, respectively. Conclusions: SVSWI is theoretically proportional to the area enclosed by the loop, reflecting the stroke work of the single ventricle. Our results revealed that we can simply predict the prognosis of single-ventricle patients based on SVSWI, as early as before the Glenn procedure, regardless of cardiac morphology. It has also been demonstrated that the prognosis of single-ventricle patients is determined by cardiac function before the Glenn procedure and that the first palliation and preservation of ventricular function are of critical for their prognosis.