Early results of optimal septal myectomy using 3-dimensional printed models

Introduction
The completeness of septal myectomy (SM) is the key to surgery of hypertrophic obstructive cardiomyopathy (HOCM), but its planning is still based on echocardiographic findings. The need to perform radical SM requires the development of new cardio-visualisation techniques for monitoring myectomy quality.

Aim
To improve results in centres treating few patients with HOCM using a new method of optimal SM with the help of 3-dimensional models to achieve an ‘ideal’ interventricular septum (IVS) thickness of 10–11 mm.

Material and methods
Between 2017 and 2018, 30 patients underwent optimal SM after computed tomography angiography, creation of a virtual 3-dimensional model of the IVS, computer-aided mapping, virtual SM and 3-dimensional printing of models of the ‘ideal’ IVS and the fragment to be removed.

Results
Initial isolated extended SM (n = 29, 97%) was effective in 23/29 (79%) patients. Four non-fatal complications were observed. A permanent pacemaker was implanted in three patients. No patients required mitral valve replacement. The mean postoperative left ventricle (LV) resting systolic gradient was 7.5 ±4.4 mm Hg, and at the latest follow-up this value was 7.1 ±4.2 mm Hg. The average weight of the excised myocardium was 12.0 γ (range: 5.8–22.5 g). At follow-up both volumetric and dimensional LV echocardiography parameters increased compared with preoperative values (p ≤ 0.007).

Conclusions
The proposed optimal SM provides intraoperative monitoring of the shape and volume of the myocardium resected to achieve the ‘ideal’ IVS, true radicality and an increase in the volumetric and dimensional parameters of the LV.