Myocardial 3-Dimensional Printing for Septal Myectomy Guidance in a Patient With Obstructive Hypertrophic Cardiomyopathy
A 33-year-old woman who reported syncope and dyspnea on exertion was diagnosed with hypertrophic cardiomyopathy and scheduled to undergo surgical septal myectomy to relieve a severe obstruction in the left ventricular (LV) outflow tract. On transthoracic echocardiography, asymmetrical septal hypertrophy and systolic anterior motion of the mitral leaflet were noted, and the peak velocity in the LV outflow tract was 4.4 m/s. Cardiac computed tomography (CT) was performed to evaluate geometric changes in the LV myocardium and coronary artery disease. A CT 3-chamber view (Figure A) and a color-coded myocardial thickness map (Figure B) generated by CT data showed asymmetrical thickening of the LV myocardium that predominantly involved the ventricular septum and had a maximal thickness of 26 mm.
For better visualization of LV anatomy and to improve surgical planning, 3-dimensional (3D) printing of the heart was performed by using the cardiac CT data. A stereolithography file of a myocardial 3D model (Figure C) was generated by dedicated software (A-view Cardiac; Asan Medical Center, Seoul, Korea) and transferred to a 3D printer system (Objet 500 Connex3; Stratasys, Minnesota, MN). The LV myocardium, papillary muscle, and intraventricular muscle band, including accessory papillary muscle, were generated with different colors by using rubberlike, transparent, and flexible materials (Tango Series; Stratasys; Figure D through F). The 3D printing enabled visualization of the geometric relationship among the hypertrophied myocardium, papillary muscle, intraventricular muscle band, and mitral annulus. For myectomy planning, the surgeon could handle and disassemble the myocardial 3D model (Movie I in the online-only Data Supplement). Extended septal myectomy was performed via an apical incision into the left ventricle (Figure G), and the hypertrophied septum and prominent muscle band were excised. Papillary muscle splitting with mitral valvuloplasty was performed to resolve the systolic anterior motion of the mitral valve. In a follow-up echocardiography obtained 4 days after surgery, the peak velocity of the LV outflow tract had decreased to 1.9 m/s.
Surgical myectomy is required in hypertrophic cardiomyopathy patients with severe disabling symptoms because of LV outflow obstruction.1 Although surgical myectomy performed in experienced centers shows low mortality in hypertrophic cardiomyopathy patients, a complex LV outflow tract anatomy, combined anomalies of the papillary muscle, and limited visualization of the LV cavity in the surgical field may increase the risk and technical challenge of the surgery.1 Although 3D printing of the heart has been used for surgical planning in patients with complex congenital heart disease, cardiac tumor, and LV aneurysm,2,3 the use of 3D printing is poorly established in hypertrophic cardiomyopathy patients. In our patient, the 3D printed model generated from cardiac CT provided intuitive information on the LV geometry, including the extent of the hypertrophied septum, location and length of the papillary muscle, and intraventricular muscle band, allowing preoperative simulation of the surgical myectomy.
Sources of Funding
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2013R1A1A1058711).
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.115.015842/-/DC1.
- © 2015 American Heart Association, Inc.
- Maron BJ,
- Yacoub M,
- Dearani JA
- Jacobs S,
- Grunert R,
- Mohr FW,
- Falk V