Initial Fitting Study of a Pediatric Continuous-Flow Total Artificial Heart

Abstract

<h3>Purpose</h3> End-stage heart failure is frequently encountered in complex congenital heart disease. Currently, we are developing a pediatric continuous flow total artificial heart (P-CFTAH). Due to the variations in congenital heart anomalies, the device should be suitable for multiple inflow and outflow structures. The purpose of this study is to evaluate the fitness of a replica of the prototype of P-CFTAH in different ages, weights and morphologies. <h3>Methods</h3> The P-CFTAH pump was derived from the adult CFTAH configuration by downsizing it with a scale factor of 0.70 (1/3 of total volume, Fig. 1a). The 3D-printed models of the pump were evaluated for anatomical fit during open-heart surgery for a variety of congenital heart anatomies. A total of 23 patients were enrolled so far (3.2-30 kg) and divided into 2 groups after the fitting study: fit or non-fit group. The pre-op thoracic size (mm), heart size (mm), cardio thoracic ratio (CTR) were measured using their pre-op chest X-rays and the differences between the 2 groups were statistically analyzed. <h3>Results</h3> Among the 23 patients, 13 patients were assigned to the fit group, and 10 patients assigned to the non-fit group after the intraoperative visual assessment. There were significant differences (p < 0.0001) between fit/non-fit groups for body weight (BW), height (Ht), body surface area (BSA), thoracic and heart size (A, B, C, D in Fig. 1b). The cutoff values of each are, BW: 5.71 kg, Ht: 66.5 cm, BSA: 0.31 m², A: 148.0 mm, B: 84.0 mm, C: 57.0 mm, D: 76.0 mm, and the area under curve of all of the parameters were >0.94. The CTR (B/A in Fig.1b) showed no significant differences among groups. <h3>Conclusion</h3> This study revealed suitability of the P-CFTAH for wide range of pediatric patients, and the range of proper fit was evident. Further studies including the evaluation of the pump performance <i>in vivo</i> and the development of even smaller pumps for the patients below the cutoff line.