A Beating Heart Testbed for the Evaluation of Robotic Cardiovascular Interventions

The improved natural hemodynamics offered by mitral valve (MV) repair strategies aims to prevent heart failure and to minimize the use of long-term anticoagulant. This combined with the reduced patient trauma offered by minimally invasive surgical (MIS) interventions, requires an increase in capabilities of MIS MV repair. The use of robotic catheters have been described in MIS applications such as navigational tasks, ablation and MV repair. The majority of the robotic catheters are evaluated in testbeds capable of partially mimicking the cardiac environment (e.g., beating heart motion or relevant anatomy), while the validation of robotic catheters in a clinical scenario is associated with significant preparation time and limited availability. Therefore, continuous catheter development could be aided by an accessible and available testbed capable of reproducing beating heart motions, circulation and the relevant anatomy in MIS cardiovascular interventions. In this study, we contribute a beating heart testbed for the evaluation of robotic catheters in MIS cardiovascular interventions. Our work describes a heart model with relevant interior structures and an integrated realistic MV model, which is attached to a Stewart platform in order to reproduce the beating heart motions based on pre-operative patient data. The beating heart model is extended with an artificial aortic valve, a systemic arterial model, a venous reservoir and a pulsatile pump to mimic the systemic circulation. Experimental evaluation showed systemic circulation and beating heart motion reproduction for 70 BPM with a mean absolute distance error of 1.26 mm, while a robotic catheter in the heart model is observed by ultrasound imaging and electromagnetic position tracking. Therefore, the presented testbed is capable of evaluating MIS robotic cardiovascular interventions such as MV repair, navigation tasks and ablation

Model predictive control of a robotically actuated delivery sheath for beating heart compensation

Minimally invasive surgery (MIS) during cardiovascular interventions reduces trauma and enables the treatment of high-risk patients who were initially denied surgery. However, restricted access, reduced visibility and control of the instrument at the treatment locations limits the performance and capabilities of such interventions during MIS. Therefore, the demand for technology such as steerable sheaths or catheters that assist the clinician during the procedure is increasing. In this study, we present and evaluate a robotically actuated delivery sheath (RADS) capable of autonomously and accurately compensating for beating heart motions by using a model-predictive control (MPC) strategy. We develop kinematic models and present online ultrasound segmentation of the RADS that are integrated with the MPC strategy. As a case study, we use pre-operative ultrasound images from a patient to extract motion profiles of the aortic heart valve (AHV). This allows the MPC strategy to anticipate for AHV motions. Further, mechanical hysteresis in the steering mechanism is compensated for in order to improve tip positioning accuracy. The novel integrated system is capable of controlling the articulating tip of the RADS to assist the clinician during cardiovascular surgery. Experiments demonstrate that the RADS follows the AHV motion with a mean positioning error of 1.68 mm. The presented modelling, imaging and control framework could be adapted and applied to a range of continuum-style robots and catheters for various cardiovascular interventions