Anselmi Amedeo, Collin Sophie, Haigron Pascal, Verhoye Jean-Philippe, Flecher Erwan
Division of Thoracic and Cardiovascular Surgery, Pontchaillou University Hospital, Rennes, France; INSERM U1099, LTSI Research Unit - Laboratoire Traitement du Signal et de l'Image, University of Rennes 1, Rennes, France.
INSERM U1099, LTSI Research Unit - Laboratoire Traitement du Signal et de l'Image, University of Rennes 1, Rennes, France.
Med Hypotheses. 2016 Jun;91:67-72. doi: 10.1016/j.mehy.2016.04.003. Epub 2016 Apr 7.
Left ventricular assist devices (LVAD) are increasingly used for long-term mechanical circulatory support and are effective in improving survival and quality-of-life of patient with advanced heart failure. Nonetheless, they are associated with significant early and late morbidity rates (including pump thrombosis, thromboembolic events, and pump dysfunction). These complications are at least partially associated with suboptimal pump positioning. Currently, we are missing tools to further improve the positioning of LVAD devices in a patient-specific fashion.
We hypothesized that the analysis of the implanted device in patients presenting selected LVAD-related complications through segmentation and three-dimensional reconstruction of CT scans may provide patient-specific information into mechanical factors contributing to pump dysfunction and thromboembolic events, with potential to guide preventive interventions against development of new complications. We also hypothesized that preoperative virtual implantation and computer-assisted surgery in candidates to LVAD implantation may help in the customization of device positioning, with potential to minimize severe complications. The hypothesis was evaluated in a multidisciplinary fashion (cardiac surgeons, biomedical engineers and biomedical images processing experts). CT scans of 14 LVAD recipients were reconstructed through semi-automatic segmentation (including the whole heart, the implanted device and the chest wall). A coordinate system was built to quantify the coaxiality of the LVAD apical cannula with the mitral annulus. Patients were stratified into Group 1 (presenting complications such as thromboembolic events, pump dysfunction or thrombosis) and Group 2 (no complications). Group 1 patients presented significantly greater average rotation of the apical cannula towards the interventricular septum (p=0.015), although no difference was observed in terms of average rotation towards the anterior or posterior left ventricular wall.
Several patient-specific factors (including left ventricular morphology and chest wall conflict with the device after wound closure) may influence the effectiveness and safety of LVAD therapy, but they are difficultly managed through the current implantation techniques. We suggest that the clinical results of LVAD treatment can be improved through preoperative virtual implantation and computer-assisted surgery (in order to guide device selection, exact site of left ventricular wall coring site). Given these preliminary results, we are examining larger patient datasets in order to further test the hypothesis. Dedicated tools for virtual implantation are currently under development.
左心室辅助装置（LVAD）越来越多地用于长期机械循环支持，对改善晚期心力衰竭患者的生存率和生活质量有效。尽管如此，它们仍与显著的早期和晚期发病率相关（包括泵血栓形成、血栓栓塞事件和泵功能障碍）。这些并发症至少部分与泵的定位不理想有关。目前，我们缺乏以患者特异性方式进一步改善LVAD装置定位的工具。
我们假设，通过对CT扫描进行分割和三维重建，分析出现特定LVAD相关并发症患者体内植入的装置，可能会提供导致泵功能障碍和血栓栓塞事件的机械因素的患者特异性信息，有可能指导针对新并发症发生的预防性干预。我们还假设，LVAD植入候选者的术前虚拟植入和计算机辅助手术可能有助于定制装置定位，有可能将严重并发症降至最低。该假设通过多学科方式（心脏外科医生、生物医学工程师和生物医学图像处理专家）进行评估。通过半自动分割（包括整个心脏、植入装置和胸壁）对14名LVAD接受者的CT扫描进行重建。建立了一个坐标系以量化LVAD心尖插管与二尖瓣环的同轴度。患者被分为第1组（出现血栓栓塞事件、泵功能障碍或血栓形成等并发症）和第2组（无并发症）。第1组患者的心尖插管向室间隔的平均旋转明显更大（p = 0.015），尽管在心尖插管向左心室前壁或后壁的平均旋转方面未观察到差异。
几个患者特异性因素（包括左心室形态以及伤口闭合后胸壁与装置的冲突）可能会影响LVAD治疗的有效性和安全性，但通过当前的植入技术很难对其进行处理。我们建议通过术前虚拟植入和计算机辅助手术（以指导装置选择、左心室壁取芯部位的确切位置）来改善LVAD治疗的临床结果。鉴于这些初步结果，我们正在检查更大的患者数据集，以进一步检验该假设。目前正在开发用于虚拟植入的专用工具。
