Impact of echocardiographic and computed-tomography assessment of Sano shunt stenosis on need for percutaneous intervention.

The decision for Sano re-intervention is made on the patient's clinical condition and imaging suggestive of conduit stenosis; however, no consensus exists on what imaging parameters best identify patients requiring re-intervention. We undertook a single center retrospective cohort study of patients who underwent a Norwood-Sano procedure to understand which echocardiographic and CT parameters were associated with intervention prior to second-stage palliation. Proximal and distal Sano Doppler velocity and peak gradients (PG) were recorded from TTE performed prior to Sano stenting or second-stage palliation if no intervention performed. Measured CT parameters included minimum and maximum diameter (mm), perimeter (mm), and cross-sectional area (mm²). Seventy-seven were identified. All had echocardiographic conduit assessment and 44 (57%) had a CT. Thirty-one (40%) required Sano stenting: 5 (16%) proximal, 16 (52%) distal and 10 (32%) both. Higher mean proximal Sano velocity and PG was associated with proximal Sano intervention (2 vs. 3 m/s, p = 0.001; 18 vs. 41mmHg, p = 0.001) while lower mean proximal Sano velocity and PG was associated with distal intervention (2.4 vs. 3.4 m/s, p = 0.03; 25 vs. 49mmHg, p = 0.03). Smaller distal Sano CT measurements were associated with distal stenting (minimum diameter: 4.1 vs. 4.9 mm,p = 0.007; maximum diameter: 5 vs. 6.2 mm, p = 0.003; perimeter: 14.8 vs. 17.7 mm, p = 0.003; CSA: 17.2 vs. 24.1mm², p = 0.003). Higher median reduction in Sano conduit minimum diameter from nominal (22% vs. 5%, p = 0.01), perimeter (25% vs. 13%, p = 0.001), and CSA (44% vs. 26%, p = 0.006) was seen if stenting was required. Though Doppler-derived gradients remain a useful screening tool, obtaining cross-sectional CT imaging in patients demonstrating clinical concern regarding Sano shunt stenosis can be beneficial in identifying patients with distal Sano stenosis.