Using virtual reality simulated implantation for fit-testing pediatric patients for adult ventricular assist devices

Abstract

Central MessageVirtual implantation of adult intracorporeal devices into children enables successful implantation and use in small children.See Commentaries on pages 138, 140, and 142. Virtual implantation of adult intracorporeal devices into children enables successful implantation and use in small children. See Commentaries on pages 138, 140, and 142. Technological advancements in ventricular assist device (VAD) support have resulted in progressive decreases in device size. This has allowed centers to push the lower limits of size for use in pediatric patients.1O'Connor M.J. Lorts A. Davies R.R. Fynn-Thompson F. Joong A. Maeda K. et al.Early experience with the Heartmate 3 continuous-flow ventricular assist device in pediatric and congenital heart disease patients: a multi-center registry analysis.J Heart Lung Transplant. 2020; 39: 573-579Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar,2Conway J. Miera O. Adachi I. Maeda K. Eghtesady P. Henderson H.T. et al.Investigators PVADWorldwide experience of a durable centrifugal flow pump in pediatric patients.Semin Thorac Cardiothorac Surg. 2018; 35: 679-681Google Scholar These limits remain uncertain, however. Although the use of virtual implantation has been described with a total artificial heart in smaller adult patients,3Ferng A.S. Oliva I. Jokerst C. Avery R. Connell A.M. Tran P.L. et al.Translation of first North American 50 and 70 cc total artificial heart virtual and clinical implantations: utility of 3D computed tomography to test fit devices.Artif Organs. 2016; 41: 727-734Crossref PubMed Scopus (10) Google Scholar the application to pediatric patients undergoing systemic VAD implantation is less clear. We have used virtual reality (VR) simulated implantation from 3-dimensional (3D) reconstruction of cross-sectional imaging (either cardiac magnetic resonance imaging or computed tomography scans) to evaluate intrapericardial placement of the HeartWare VAD (HVAD; Medtronic, Dublin, Ireland) and the HeartMate3 (Abbott, Chicago, Ill) intrapericardial pumps in children. Our criteria for a pump “fitting” is that the tip of the pump inflow lies below the atrioventricular (AV) valve annulus (fully within the ventricle) when the pump is placed inside the chest wall. This should preserve AV valve function and result in less distortion of cardiac structures, which may be especially important when trying to preserve right ventricular function on VAD support. We provide 3 images of similar-sized children (patient 1: 17 kg, 0.67 m2 with a single systemic right ventricle; patient 2: 14.3 kg, 0.66 m2 with dilated cardiomyopathy; patient 3: 14.6 kg, 0.65 m2 with pacemaker-induced cardiomyopathy following repair of an AV septal defect and mechanical left AV valve replacement). Despite being heavier than the other 2 patients, patient 1 had the shortest distance between the AV valve and chest wall (∼5 cm vs ∼7 cm) (Figure 1). Patients 2 and 3 underwent successful HVAD implantation (Figure 2). Patient 1 was not felt to be a candidate for HVAD implantation, because during VR placement of the pump within the chest, the pump inflow would have been located within the system AV valve annulus. She had an extracorporeal device placed instead.Figure 2Coronal cross-sectional imaging of patient 2 (A) and patient 3 (B). The tip of the ventricular assist device (VAD) inflow cannula is indicated by the white arrow. The position of the left atrioventricular valve annulus is indicated by the red arrow and either the dashed red line in the native valve annulus (A) or the radioopaque mechanical valve prosthesis (B). In both cases, there is sufficient room between the inflow to the VAD and the annulus.View Large Image Figure ViewerDownload (PPT) VR implantation allows for a more accurate assessment of pump position within the chest, including the angle of the inflow cannula toward the AV valve, the impact of chest wall anatomy, and the relationship between the 3D volume of the pump and the dimensions of the ribcage (Figure 3, Videos 1 and 2). This has informed the location of pump fixation to the chest wall (which we commonly perform in smaller patients). Virtual fit-testing has enabled successful implantation of the HeartMate3 in 2 of the smallest patients described in the literature to date (both with a body surface area <.8 m2), as well as one of the smallest HVAD patients (14.3 kg).Video 2Three-dimensional video of virtual fit-testing with simultaneous audio commentary and explanation. The heart is reconstructed using a shell placed around the blood pool on cross-sectional imaging. This allows for visualization of the cardiac chambers and some assessment of the location of large trabeculations, which can be especially useful in systemic right ventricles. Colors are applied to the reconstructed image to assist with placement. The shell around the blood pool is light blue, the rib cage is yellow, and the atrioventricular (AV) valve annulus is shown in red. Surgical implantation will displace the ventricle from the chest wall and rib cage, so the implantation cannot determine the precise positioning of the device within the ventricle. However, we view the position of the AV valve annulus as relatively immobile in the short term and place a premium on preserving systemic AV valve function whenever possible. Therefore, by placing the VAD within the rib cage in a position with the inflow directed at the AV valve and clear of the largest trabeculations, we are able to assess the distance between the annulus and the tip of the inflow. Video available at: https://www.jtcvs.org/article/S2666-2507(20)30597-6/fulltext.View Large Image Figure ViewerDownload (PPT)Figure 3Screen captures of the virtual implantation in 3-dimensional (3D) virtual reality (VR). The fit-testing is performed in 3D VR space using an HTC Vive virtual reality headset (HTC, Taoyuan City, Taiwan) and I2I (Imager to Interventionalist) virtual reality software (VARYFII Imaging, Dallas, Tex). Shown are 2-dimensional (2D) screen captures of the live 3D fitting process to demonstrate the components present in the VR space. A, Placement of the virtual ventricular assist device (VAD; white) into the reconstructed heart (light blue) and rib cage (yellow) of patient A. B, View of the tricuspid valve annulus (red) within the heart (light blue) and VAD (white).View Large Image Figure ViewerDownload (PPT) The need for informed consent regarding the publication of the study data was waived by the UT Southwestern Medical Center's Institutional Review Board. https://www.jtcvstechniques.org/cms/asset/036a4657-939a-403c-b341-8dc8aac08168/mmc1.mp4Loading ... Download .mp4 (65.14 MB) Help with .mp4 files Video 1Two-dimensional video of virtual fit-testing with simultaneous audio commentary and explanation. The heart is reconstructed using a shell placed around the blood pool on cross-sectional imaging. This allows for visualization of the cardiac chambers and some assessment of the location of large trabeculations, which can be especially useful in systemic right ventricles. Colors are applied to the reconstructed image to assist with placement. The shell around the blood pool is light blue, the rib cage is yellow, and the atrioventricular (AV) valve annulus is shown in red. Surgical implantation will displace the ventricle from the chest wall and rib cage, so the implantation cannot determine the precise positioning of the device within the ventricle. However, we view the position of the AV valve annulus as relatively immobile in the short term and place a premium on preserving systemic AV valve function whenever possible. Therefore, by placing the VAD within the rib cage in a position with the inflow directed at the AV valve and clear of the largest trabeculations, we are able to assess the distance between the annulus and the tip of the inflow. Video available at: https://www.jtcvs.org/article/S2666-2507(20)30597-6/fulltext.https://www.jtcvstechniques.org/cms/asset/cd26c0c3-bb12-49cf-81d1-3b7b1b878c65/mmc2.mp4Loading ... Download .mp4 (160.78 MB) Help with .mp4 files Video 2Three-dimensional video of virtual fit-testing with simultaneous audio commentary and explanation. The heart is reconstructed using a shell placed around the blood pool on cross-sectional imaging. This allows for visualization of the cardiac chambers and some assessment of the location of large trabeculations, which can be especially useful in systemic right ventricles. Colors are applied to the reconstructed image to assist with placement. The shell around the blood pool is light blue, the rib cage is yellow, and the atrioventricular (AV) valve annulus is shown in red. Surgical implantation will displace the ventricle from the chest wall and rib cage, so the implantation cannot determine the precise positioning of the device within the ventricle. However, we view the position of the AV valve annulus as relatively immobile in the short term and place a premium on preserving systemic AV valve function whenever possible. Therefore, by placing the VAD within the rib cage in a position with the inflow directed at the AV valve and clear of the largest trabeculations, we are able to assess the distance between the annulus and the tip of the inflow. Video available at: https://www.jtcvs.org/article/S2666-2507(20)30597-6/fulltext. Commentary: One size might not fit all: Planning ventricular assist device implantation in young childrenJTCVS TechniquesVol. 6PreviewOften the most complex situations in pediatric cardiothoracic surgery involve intraoperative decision making while utilizing unconventional techniques under time pressure. Thoughtful preoperative surgical planning can facilitate ventricular assist device (VAD) implantation in children. Full-Text PDF Open AccessCommentary: Virtual reality in presurgical planning: The future is already hereJTCVS TechniquesVol. 6PreviewThe study by Davies and colleagues1 in this issue of the Journal highlights the utility of virtual reality (VR) in the presurgical assessment of implantation of adult-sized ventricular assist device (VAD) in pediatric patients. The authors demonstrate the application of this innovative technology for intrapericardial placement of the Heartware HVAD and Heartmate3 in 3 patients with body surface area ranging from 0.65 to 0.67 m2. Full-Text PDF Open AccessCommentary: Virtual fit reality and tailored approach in ventricular assist device implantationJTCVS TechniquesVol. 6PreviewRecent technical advances in medicine have made several new tools available to surgeons in the preoperative and intraoperative care of patients for more precise diagnosis, planning, and execution of surgical procedures. The application of 3-dimensional (3D)-printing, computer modeling, high-resolution computed tomography CT scan and reconstruction, 3D echocardiography, and, more recently, virtual reality are examples of these sophisticated technological advances used by surgeons toward a personalized patient approach. Full-Text PDF Open Access

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