Three-dimensional heart modelling of hypertrophic obstructive cardiomyopathy for in situ patient-specific simulation to optimise septal myectomy

Objective: Hypertrophic obstructive cardiomyopathy (HOCM) develops in at least 1 out of 715 young adults. Patients who are refractory to medical therapy qualify for septal myectomy. Due to anatomy, serious complications such as ventricular septal defect and heart block may occur. Establishing cardiovascular magnetic resonance (CMR)–based 3-dimensional (3D) models as part of preoperative planning and training has the potential to decrease procedure-related complications and improve results. Methods: CMR images were used to segment cardiac structures. Left ventricular wall thickness was calculated and projected on top of the in silico model. A 3D model was printed with a red layer indicating a wall thickness exceeding 15 mm and used for preoperative resection planning and patient counseling. To provide preoperative patient-specific in situ simulation, the planned resection volume was replaced with silicone in a second model. For perioperative quality control, resected silicone was compared with resected myocardial tissue. The impact of the models was evaluated descriptively through consultation of both the cardiothoracic surgeon and patients and through patient outcomes. Results: Three-dimensional in silico and 3D-printed heart models of 5 patients were established preoperatively. Since the introduction of the models in October 2020, the surgeon feels better prepared, more confident, and less difficulty with making decisions. In addition, patients feel better informed preoperatively. Conclusions: Using 3D heart models optimized preoperative planning and training, intraoperative quality control, and patient consultation. Reduction of procedure-related complications and clinical outcome should be studied in larger cohorts.</p

In situ patient-specific simulation of complex cardiac surgery: A simulation-based observational study with 3D heart models

Introduction Low volume and high complex cardiac surgery such as resection of excess heart muscle (myectomy) has proven to be effective, yet, serious complications such as a ventricular septal defect, and complete heart block leading to pacemaker implantations may occur even for experienced surgeons. In situ simulation-based practice before actual surgery might improve patient outcomes. As simulation and clinical practice becomes more and more intertwined, we aimed to develop and implement three-dimensional (3D) heart models in preoperative planning and training to improve pre-operative patient-specific anatomy insights and surgical technique in an observational study to ultimately improve surgical outcome. Methods Eight consecutive patients scheduled for surgical myectomy received cardiac Magnetic Resonance Imaging (MRI) based 3D-planning from September 2020 to August 2022. The dedicated cardiac MRI examination resulted in a high resolution 3D sequence of the heart and thoracic blood vessels. Models increased in complexity over time from a) an in silico anatomical model, to b) 3D-printed septal myectomy planning, to c) pre-operative in situ surgical practice on a silicone model, and to d) intraoperative assessment of actual heart muscle resection compared to pre-operative planning. The models were also used for patient consultation and surgical informed consent. Our small sample size was deemed too small for quantitative analysis of patient outcomes. Results & Discussion An in silico 3D anatomical model of the heart with height map is visualised in Figure 1a. Thickened heart tissue exceeding 15 mm was printed in red for visual guidance of surgical resection (Figure 1b). In situ simulated resection of excess heart tissue was simulated on the silicone model one day before the actual surgery (Figure 1c), and allowed for adjustment of the planned resection. The pre-operative surgical plan and actual resected myocardial tissue volume and size were compared intraoperatively (Figure 1d). Since introduction of the patient-specific models, surgeons feel better prepared, more confident, and feel better supported making pre- and intra-operative decisions. Additionally, patients feel better informed about the actual procedure during outpatient consultation. In situ patient-specific simulation of complex cardiac surgery has become regular surgical practice in our hospital. It is recommended to implement and evaluate the presented workflow in other cardio-thoracic surgery centres, and for other disciplines to demonstrate improvement in patient outcomes. Keywords High Fidelity Simulation Training; Heart surgery; Three-Dimensional Imaging; Just-in-time simulation References/Acknowledgements Aggarwal R. Just-in-time simulation-based training. BMJ Quality & Safety 2017;26:866-868. https://dx.doi.org/10.1136/bmjqs-2017-007122 Ralph-Edwards A, Vanderlaan RD, Bajona P. Transaortic septal myectomy: techniques and pitfalls. Annals of Cardiothoracic Surgery 2017;6(4):410-415. https://doi.org/10.21037/acs.2017.07.0