24 Accuracy of computed tomography for detecting great vessel stenosis or hypoplasia in complex congenital heart disease prior to superior bidirectional cavopulmonary connection: comparison with cardiac catheterization and surgical findings

Aim This study sought to investigate diagnostic accuracy and safety of computed tomography (CT) in assessing great vessel stenosis/hypoplasia prior to superior bidirectional cavopulmonary connection (BCPC) compared with cardiac catheterisation and surgical findings. Method and results Twenty-seven patients (37% after Norwood operation) who were assessed by CT prior to BCPC between January 2010 and June 2016, at median age of 229 days (range 96 days–3.2 years), were included. Median weight at the time of BCPC was 8.3kg (4.0–13.4kg), median time from previous surgery 222days (97–885 days). Sixteen of the patients also underwent cardiac catheterisation. Patients received significantly higher radiation dose at cardiac catheterisation than at CT (median 2.6, IQR 1.6,3.5 mSv versus 1.2, IQR 1.0, 1.9 mSv; respectively;p=0.040). Four patients (25%) suffered minor complications from cardiac catheterisation. There were no complications from CT scan. All cardiac catheterisations were performed under general anaesthesia. No sedation was required for any of the patients for CT. Based on surgical findings, the accuracy of CT for detecting stenosis/hypoplasia of either pulmonary artery was 99.7%. Nine right and 11 left pulmonary artery branches were enlarged at the time of surgery. CT did not miss any stenosis/hypoplasia of branch pulmonary arteries and reported 2 cases of branch pulmonary artery hypoplasia which were considered at the time of BCPC surgery to be normal. Conclusion CT may replace cardiac catheterisation for identification of great vessel stenosis or hypoplasia in patients before BCPC. This requires less radiation, carries less morbidity and can be performed without sedation in this fragile group of patients.