Three-Dimensional Printing as an Aid in Transcatheter Closure of Secundum Atrial Septal Defect With Rim Deficiency
In Vitro Trial Occlusion Based on a Personalized Heart Model
A 54-year-old woman was admitted with systolic murmur and exertional dyspnea. ECG demonstrated right ventricular hypertrophy with an rsR’ pattern in the leads on the right side of the chest. Chest x-ray revealed cardiomegaly, increased pulmonary arterial vascularity, and prominent main pulmonary artery segment. The cardiothoracic ratio was 57%. Transthoracic echocardiography showed a large secundum atrial septal defect (ASD) with left-to-right shunt, and the maximal diameter was 30 mm. Doppler-calculated systolic pulmonary arterial pressure (SPAP) was 76 mm Hg. The transesophageal echocardiography was absent because of contraindications, and coronary arterial disease was excluded with multislice computed tomography (MSCT). Furthermore, MSCT demonstrated that the size of ASD was 28×35 mm and that a partial defect occurred in the posterior-inferior rim of ASD with normal pulmonary vein anatomy (Figure 1). Because of the large size and poor septal rim, surgical repair was suggested for the patient. However, she resisted the surgery intensely and insisted on transcatheter closure.
On the basis of the MSCT imaging, a personalized heart model was produced with 3-dimensional printing (Figure 2A and Movie I in the online-only Data Supplement). Subsequently, in vitro trial occlusion was performed in the elastic rubber model for preoperative evaluation. The model showed that a 38-mm Amplatzer septal occluder (St. Jude Medical) would cover the ASD successfully (Figure 2B and 2C). Three days later, informed consent was obtained, and the patient underwent right-sided heart catheterization and transcatheter closure successfully, as illustrated by the use of the rapid prototyping. Right-sided heart catheterization demonstrated that the SPAP was 70 mm Hg, ratio of pulmonary to systemic flow (Qp/Qs) was 2.2, and pulmonary vascular resistance was 3.7 Wood units. During inhalation of oxygen, the SPAP decreased to 56 mm Hg, Qp/Qs increased to 2.8, and pulmonary vascular resistance was 2.4 Wood units. After implantation of the device, the immediate postocclusion SPAP was further reduced to 40 mm Hg. Transthoracic echocardiography verified the correct position of the occluder without abrasion of surrounding tissue (Figure 3). Furthermore, no residual shunt was detected. At the 1-year follow-up, the patient’s symptoms were relieved greatly, and no complications occurred. There was a significant decrease in right ventricular size (basal dimension, 5.5–4.2 cm), and the Doppler-calculated SPAP was 36 mm Hg. Repeat MSCT confirmed complete occlusion of the ASD (Figure 4).
In transcatheter closure of an ASD, the surrounding rim dimension is a crucial parameter that determines the placement of the device. Unfortunately, some of the large ASDs are usually associated with deficient rim, which makes device implantation difficult and increases the risk for device embolization. Although successful transcatheter closure has been reported in some ASDs with deficient posterior-inferior rim, it is still difficult to predict successful closure in these patients.1,2 The transcatheter closure has been regarded as the preferred strategy in patients with ASD, but the potential complications should be considered preoperatively. Therefore, it is necessary to develop a feasible method to identify the appropriate candidates, especially for large ASDs with rim deficiency.
MSCT can provide the high-quality imaging for anatomic evaluation of an ASD, including maximal defect size and surrounding rim morphology. From the MSCT images, a personalized heart model can be produced with 3-dimensional printing,3 which contributes to the preoperative evaluation of ASD with rim deficiency. The trial occlusion in the model can prevent unnecessary transcatheter closure in patients and thus decrease related complications. To the best of our knowledge, this is the first application of 3-dimensional printing in the transcatheter closure of an ASD with rim deficiency. In this patient, our findings suggested that 3-dimensional printing has the potential to screen the appropriate candidates.
Sources of Funding
The research was supported by Beijing Natural Science Foundation (7162160) and National Natural Science Foundation of China (81341045).
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.115.020735/-/DC1.
- © 2016 American Heart Association, Inc.