Effectiveness of a patient-specific 3-dimensional printed model in Septal Myectomy of hypertrophic cardiomyopathy

OBJECTIVE: Advanced cardiovascular surgery in structural heart disease require accurate pre-operative evaluation. Most of non-invasive imaging technologies remain limited in two-dimensional and show insufficiency of visualization for procedural planning. The aim of this study was to discuss the value of patient-specific 3-dimensional (3D) printing in treatment of hypertrophic cardiomyopathy (HCM). METHODS: Patient-specific 3D-printed models were constructed preoperatively in 12 consecutive HOCM patients which come to Beijing Anzhen Hospital for surgical treatment from October 2016 to March 2017. Image files were extracted from multi-slice computed tomography images, 3D models were constructed by the Mimics 19.0 software and generated by Objet350 Connex3 3D printer. The 3D-printed models were made with soft material that can be surgically performed. The modified Morrow myectomy of the model was performed before the operation. Clinical characters and echocardiographic parameters were recorded. RESULTS: There was no significant difference in tissue volume between the models and specimens. Preoperative and postoperative echocardiography showed the septal thickness was reduced from 18.8±4.5 mm to 12.7±3.3 mm (p<0.001), the left ventricular outflow tract obstruction was adequately relieved (83.0±27.73 mm Hg to 8.7±6.5 mm Hg, p<0.001), and the SAM disappeared completely after the operation. Cardiac function was improved in all patients (New York Heart Association functional class III to class I/II). CONCLUSIONS: The proposed optimal 3D-modelled septal myectomy allows intraoperative monitoring of the shape and volume of the myocardium resection to achieve the ‘ideal’ interventricular septum. It eliminates obstruction in the LVOT and SAM, resulting in LV remodeling with an increase in LV end-diastolic volume and diameter at early follow-up.