Image based evaluation of mediastinal constraints for the development of a pulsatile total artificial heart

Abstract

BackgroundGood anatomical compatibility is an important aspect in the development of cardiovascular implants. This work analyzes the interaction of the pump unit of an electrically driven pulsatile Total Artificial Heart (TAH) and the mediastinum. For an adequate compliance, both overall dimensions and alignment of inlets and outlets must be matched.MethodsCross-sectional medical image data of 27 individuals, including male and female patients suffering from end stage heart failure, was segmented and reconstructed to three dimensional (3D) surface models. Dimensions and orientations of relevant structures were identified and analyzed. The TAH surface model was virtually placed in orthotopic position and aligned with atrioventricular valves and big vessels. Additionally seven conventional cadaver studies were performed to validate different pump chamber designs based on virtual findings. Thereby 3D-coordinates were captured and introduced to the virtual environment to allow quantitative comparison between different individuals.ResultsSpatial parameters varied more in male patients with higher values if heart failure persists. Good correlation of the virtual analysis both to literature data and conventional cadaver studies could be shown. The full data of the 27 individuals as well as the summarized values found in literature are enclosed in the appendix. By superimposing the TAH-volume model to the anatomy, various misalignments were found and the TAH-design was adjusted.ConclusionsVirtual fitting allows implant design adjustments in realistic anatomy which has not been influenced by thoracotomy. Higher numbers of relevant individuals can be reasonably investigated in the virtual environment and quantitatively correlated. Using this approach, conventional cadaver studies can be significantly reduced but not obviated, due to the unavailable haptic feedback and immobility of potentially compressed structures.

Virtual implantations to transition from porcine to bovine animal models for a total artificial heart

“…To our knowledge, this is the first‐time virtual implantations have been used in an animal model. Other TAH developers have used virtual implantation methods for adjusting the design to fit the human patient, and to estimate the number of patients who will be within the target size . However, the shape of the thorax differs between species.…”

“…Other TAH developers have used virtual implantation methods for adjusting the design to fit the human patient, and to estimate the number of patients who will be within the target size. 11,18,19 However, the shape of the thorax differs between species. Humans have elliptical, flattened chests, whereas intermediate-sized mammals have narrower, slightly pointed chests, and large mammals, have round to downward-pointing ovular chests.…”

An Original Valveless Artificial Heart Providing Pulsatile Flow Tested in Mock Circulatory Loops

“…With the 30% loss observed on our functional model of the pump mechanism, this corresponds to a measured stroke volume of 30 mL and 170 ejections per minute are necessary to pump 5 L/min through the circuit. While the current functional model is bulky, the next iteration will be much more compact, with an internal motor, and its dimensions will be between 8 cm for its smaller dimension and 11 cm for its largest one, which will allow it to fit in most patients (19) (Fig. 2B).…”

Design and Evaluation of a Fully Implantable Control Unit for Blood Pumps

“…Anatomical fitting studies, both virtual and cadaver studies, were conducted to determine the optimal size and location of the pump unit in a former study [ 11 ]. As a result, the TAH motor unit and ventricles have a diameter of 85 mm and a height of 90 mm.…”