Pulmonary artery banding (PAB) and ventriculo-arterial discordance (VAD) were reported to be risk factors of subaortic stenosis in univentricular heart. The aim of this study was to evaluate efficacy of Damus-Kaye-Stansel (DKS) anastomosis. Of all 89 patients undergoing total cavo-pulmonary connection (TCPC) in our center since April 1996, 38 had VAD with high pulmonary blood flow, and had received PAB. Twenty-one of 38 had undergone DKS anastomosis due to subaortic stenosis or due to morphological hypertrophy of the outlet septum (DKS group); the other 17 had not yet (no-DKS group). Percentage end-systolic volume of the systemic ventricle and percentage subaortic lesion in both groups significantly decreased after TCPC (P<0.01). Pressure gradient across systemic outflow tract after TCPC was low in both groups at rest. The gradient in DKS group did not differ from those in control group with ventriculo-arterial concordance (VAC) (P>0.1). Ventricular outflow tract after DKS anastomosis might behave like that of VAC even when dobutamine is loaded, suggesting that the anastomosis should be carried out in many patients with this entity even if stenosis across systemic ventricular outflow is not significant, considering possible stenosis in the future.