Comprehensive assessment of morphology and severity of atrial septal defects in adults by CT

Background: Cardiac CT is an excellent tool for evaluating the anatomy of a secundum atrial septal defect (ASD). However, a comprehensive assessment of its usefulness, including measurement of the pulmonary to systemic blood flow ratio in secundum ASD patients, has not been performed. Objective: Therefore, this study was designed to evaluate the usefulness of CT for assessing the hemodynamics of secundum ASD in adults compared with transesophageal echocardiography (TEE), transthoracic echocardiography, and invasive catheterization. Methods: Fifty adult patients with secundum ASD were enrolled. Cardiac CT scans (128-slice multidetector CT instrument) were acquired. These were followed by 2-dimensional reconstruction of the secundum ASDs to determine the defect size, the rim length between the outer edge of the defect, and the pulmonary to systemic blood flow (Qp/Qs) ratio. Results: The maximum sizes of the secundum ASDs derived from CT and TEE studies were comparable (21.2 ± 8.0 vs 20.0 ± 7.3 mm; P = .41; r = 0.960; P < .001). The rim lengths for the aortic, mitral, and tricuspid valves; the inferior vena cava; and posterior atrium were also comparable between CT and TEE measurements. The mean Qp/Qs ratio that was derived from CT measurements was comparable with that found by invasive catheterization (2.3 ± 0.7 vs 2.3 ± 0.8; P = .73; r = 0.786; P < .001). Conclusion: Cardiac CT is feasible for assessing pathology and the severity of secundum ASD in adults.