BACKGROUND

Double outlet right ventricle (DORV) with two well-developed ventricles and with a remote ventricular septal defect (VSD) may present a therapeutic challenge. Echocardiographic imaging of such complex cases does not always provide all of the information required to decide on an operative approach (biventricular or univentricular) and to design an intracardiac baffle to direct left ventricular outflow through the VSD and to the aorta for biventricular repair. A three dimensional (3D) printed model of the heart based upon data derived from computed tomography (CT) or magnetic resonance imaging (MRI) may contribute to a more complete appreciation of the intracardiac anatomy.

METHODS

From April to September 2015, six consecutive patients with DORV and remote VSD underwent CT/MRI scans. Data sets from these studies were used to generate life-size 3D models using a 3D printer. We compared the assessment of 3D printed heart model findings with information obtained from echocardiography, CT, or cardiac MRI and with details of the surgeon's intraoperative direct observations when available. Quantification of the information provided by the 3D model was achieved using a unique scale that was created for the purpose of this study. The accuracy and utility of information derived preoperatively from the models were assessed.

RESULTS

Six data sets from six patients were analyzed. Five data sets could be successfully used to create sandstone models using 3D printing. The five patients ranged from 7 months to 11 years of age and weighed 6.7 to 26 kg. The spatial orientation of the heart in the thorax, the relationships of the great arteries and the semilunar valves, the size and location of the VSD were well appreciated in all models, as were the anticipated dimensions and orientation of a surgically planned interventricular baffle. Three of the five patients underwent successful biventricular repair.

CONCLUSION

The 3D printed models scored higher than conventional imaging, with respect to most aspects of the surface spatial orientation and intracardiac anatomy. The models are a useful adjunct in preoperative assessment of complex DORV. The unique scale helps quantify the advantages and limitations of the 3D heart models.