AN EXTRA-AORTIC SOFT ROBOTIC CARDIAC SUPPORT DEVICE: PATIENT-SPECIFIC IN-VITRO AND IN-VIVO EVALUATION

• Published in: International journal of artificial organs 2023-07, Vol.46 (7), p.413
• Main Authors: Dual, S A, Rohan, S, Arduini, M, Kight, A, Pirozzi, I, Chen, I, Hiesinger, W, Ennis, D B
• Format: Article
• Language: English
• Subjects: Actuation; Aorta; Blood flow; Blood pressure; Blood vessels; Cardiac output; Congestive heart failure; Coronary vessels; Deformation; Design; Heart failure; Hemodynamics; Hypertension; Low flow; Magnetic resonance imaging; Physiology; Pressure reduction; Pulsation; Robotics; Soft robotics; Systolic pressure; Thrombosis
• ISSN: 0391-3988; 1724-6040

Objectives: Heart failure is a serious cardiac condition currently treated with continuous flow implantable pumps that are blood contacting, dampen blood flow pulsatility, and lack patient-specific design. Here, we report the design and function of a soft robotic counter pulsation device that smoothly conforms externally to the aortic vessel wall. Cuff geometry and size was scaled to subject aortic diameter. Methods: In a patient-specific mock loop, we accurately recreate hemodynamic conditions of a patient with high blood pressure and clinically diagnosed diastolic heart failure (cardiac output: 5.17 L/min, peak flow: 266 mL/s, blood pressure: 150/69 mmHg) in interaction with a compliant model of the patient's aorta. We assessed intra-vessel systolic pressure reduction resulting from various actuation paradigms and we recorded time-resolved blood flow as well as wall deformations using magnetic resonance imaging (MRI). The device was subsequently implanted on the ascending aorta of two healthy pigs to assess the physiological response of the healthy heart to counter-pulsation support. Results: In vitro, the soft robotic device decreased afterload in the simulated patient by 10mmHg, while preserving blood flow pulsatility. High resolution MRI experiments showed anatomically favorable deformations of the vessel wall, efficient physiological flows, and minimal flow disturbance. In vivo, aortic pressure reduction was 3mmHg, and cardiac output increased instantaneously by 64% and 4% in the two animals respectively upon aortic counter-pulsation support. Conclusions: In this proof-of-principle study, soft robotic extra-vascular support effectively lowers afterload, which is expected to reduce strain on the heart. The device has low risk for thrombus due to no blood contact and low flow disturbances. The soft design renders the device adaptable to different vessel sizing and implantable using minimally invasive surgery. Further studies are necessary to elucidate the physiological mechanisms of counter-pulsation as means to increase cardiac output and for assessing applicability as durable support for patients with heart failure.