Critical Care Management of the Acute Postimplant LVAD Patient.

Left ventricular assist devices (LVADs) improve survival and quality of life in refractory end-stage heart failure. However, the therapy itself is associated with some degree of morbidity and mortality at highest risk during the first 30 days postimplantation. Management of the patient with a freshly implanted LVAD requires an in-depth understanding of the acute postimplant period and common critical care issues including coagulopathy, hemodynamic lability, and metabolic derangements. This requires meticulous hemostatic control and a firm understanding of hemodynamic principles that focus on optimizing end-organ perfusion, right-ventricular function, and measured LVAD titration. This contemporary practical guide to management of the acute postimplant LVAD patient includes a focused approach to troubleshooting common LVAD issues that may arise from the operating room to discharge from critical care.

Surface-Based CT-TEE Registration of the Aortic Root.

Transcatheter aortic valve implantation (TAVI) is a minimally invasive alternative to conventional aortic valve replacement for severe aortic stenosis in high-risk patients in which a stent-based bioprosthetic valve is delivered into the heart via a catheter. TAVI relies largely on single-plane fluoroscopy for intraoperative navigation and guidance, which provides only gross imaging of anatomical structures. Inadequate imaging leading to suboptimal valve positioning contributes to many of the early complications experienced by TAVI patients, including valve embolism, coronary ostia obstruction, paravalvular leak, heart block, and secondary nephrotoxicity from excessive contrast use. Improved visualization can be provided using intraoperative registration of a CT-derived surface to transesophageal echo (TEE) images. In this study, the accuracy and robustness of a surface-based registration method suitable for intraoperative use are evaluated, and the performances of different TEE surface extraction methods are compared. The use of cross-plane TEE contours demonstrated the best accuracy, with registration errors of less than 5 mm. This guidance system uses minimal intraoperative interaction and workflow modification, does not require tool calibration or additional intraoperative hardware, and can be implemented at all cardiac centers at extremely low cost.

2D ultrasound augmented by virtual tools for guidance of interventional procedures.

Many intracardiac procedures can currently be performed on the heart only after it has been arrested, and the patient has been placed on cardio-pulmonary bypass. We have developed a new method for operating on multiple targets inside the beating heart, and describe a procedure for accessing them under virtual-reality (VR)-assisted image guidance that combines real-time ultrasound with a virtual model of tools, and the surgical environment acquired from pre-operative images. This paper presents preliminary results aimed at assessing the operator's ability to accurately position and staple an artificial valve to a "valve orifice" within a cardiac phantom when guidance is performed via ultrasound alone, and with US augmented by the VR environment.