ANIMAL-BASED CFD ANALYSIS OF HEMODYNAMICS IN PULMONARY ARTERY WITH AN IMPLANTED PRESSURE SENSOR

Objectives: Pulmonary artery pressure sensors (PAPS) are proposed for the monitoring of heart failure patients. Methods: To proof an ability of an in-silico study to assess a risk of the sensor thrombogenicity a chronic animal study using pigs was conducted. Computed tomography (CT) data was acquired before and immediately after implantation, as well as one month follow-up. Devices were implanted into 10 pigs, each one in the left and right pulmonary artery (PA). The implantation procedure aimed at facilitating favorable and non-favorable positioning of the devices to increase chances of thrombus formation. Eight devices were positioned non-optimally. Pre-interventional PA geometries were reconstructed from the respective CT images, and the devices were virtually implanted at the exact sites and orientations indicated by the follow-up CT. Transient intra-arterial hemodynamics were calculated using computational fluid dynamics. Wall shear stresses (WSS) and oscillatory shear indices (OSI) before and after device implantation were compared. Results: Simulations revealed no relevant changes in any investigated hemodynamic parameters due to device implantation. Even in cases, where devices were implanted in a non-favorable manner, no marked differences compared to devices implanted in an optimal position were found. Before implantation WSS was 2.35 ± 0.47 Pa, whereas OSI was 0.08 ± 0.17. Areas affected by low WSS magnitudes were 2.5 ± 2.7 cm², whereas the areas affected by high OSI were 18.1 ± 6.3cm². After device implantation, WSS and OSI were 2.45 ± 0.49 Pa and 0.08 ± 0.16. Surface areas affected by low WSS and high OSI were 2.9 ± 2.7 cm², and 18.4 ± 6.1 cm². Conclusions: The results indicates that no clinically relevant differences in hemodynamics are occurring after device implantation, even at non-optimal positioning of the sensor. Simultaneously, no embolic events were observed, suggesting that the risk for thrombus formation after device implantation is low.