A Physiological Controller for Turbodynamic Ventricular Assist Devices Based on Left Ventricular Systolic Pressure

Abstract

The current article presents a novel physiological feedback controller for turbodynamic ventricular assist devices (tVADs). This controller is based on the recording of the left ventricular (LV) pressure measured at the inlet cannula of a tVAD thus requiring only one pressure sensor. The LV systolic pressure (SP) is proposed as an indicator to determine the varying perfusion requirements. The algorithm to extract the SP from the pump inlet pressure signal used for the controller to adjust the speed of the tVAD shows robust behavior. Its performance was evaluated on a hybrid mock circulation. The experiments with changing perfusion requirements were compared with a physiological circulation and a pathological one assisted with a tVAD operated at constant speed. A sensitivity analysis of the controller parameters was conducted to identify their limits and their influence on a circulation. The performance of the proposed SP controller was evaluated for various values of LV contractility, as well as for a simulated pressure sensor drift. The response of a pathological circulation assisted by a tVAD controlled by the introduced SP controller matched the physiological circulation well, while over- and underpumping events were eliminated. The controller presented a robust performance during experiments with simulated pressure sensor drift.

Standardized Comparison of Selected Physiological Controllers for Rotary Blood Pumps: In Vitro Study

“…Particularly, two of the implemented controllers (described below) were selected due to their outperformance over another five controllers and the CS operation presented in the comparison study of Pauls et al . The other four controllers were selected due to their clear outperformance over the CS operation that they presented when published , while they offered a reasonable concept variability. For the case of controllers presented in , they have been previously developed in our group and, therefore, we have a deep insight of both, while they have been successfully evaluated in vivo .…”

“…The other four controllers were selected due to their clear outperformance over the CS operation that they presented when published , while they offered a reasonable concept variability. For the case of controllers presented in , they have been previously developed in our group and, therefore, we have a deep insight of both, while they have been successfully evaluated in vivo . Each principle is described below.…”

“…However, it has been proven that estimators lack robustness and accuracy (4). Recent approaches are based on invasive signals, such as the LV pressure, the aortic pressure, the LV volume, or the measured pump flow (5)(6)(7)(8)(9)(10)(11). Most of these approaches claim to aim at imitating the Frank-Starling mechanism of the healthy heart by estimating or measuring the preload condition of the LV.…”

A Starling‐like total work controller for rotary blood pumps: An in vitro evaluation

“…Starling‐like controllers have been proposed, which have been based on Guyton’s adaption of the Starling mechanism that relates ventricular preload to a target RBP flow, or have been based on the preload recruitable stroke work relationship . While these controllers have demonstrated the ability to balance circulatory volumes, they do not consider ventricular workload as a feedback and therefore result in a different cardiac output to the rest condition when left heart function deteriorates or improves . To improve on previous Starling‐like controllers and compensate for changes in ventricular workload, a superior alternative may be to implement a physiological controller that mimics the Starling stroke work response by regulating RBP hydraulic work based on measured LVSW and LVEDP.…”

“…13 While these controllers have demonstrated the ability to balance circulatory volumes, they do not consider ventricular workload as a feedback and therefore result in a different cardiac output to the rest condition when left heart function deteriorates or improves. 14,15 To improve on previous Starling-like controllers and compensate for changes in ventricular workload, a superior alternative may be to implement a physiological controller that mimics the Starling stroke work response by regulating RBP hydraulic work based on measured LVSW and LVEDP. This study therefore aimed to compare constant speed control to a Starling-like total work controller (SL-TWC) that balances circulatory volumes and compensates for changes in left ventricular workload.…”