PERKAT RV: first in vivo data of a novel right heart assist device

Artificial Muscles and Soft Robotic Devices for Treatment of End-Stage Heart Failure

Medical soft robotics constitutes a rapidly developing field in the treatment of cardiovascular diseases, with a promising future for millions of patients suffering from heart failure worldwide. Herein, the present state and future direction of artificial muscle-based soft robotic biomedical devices in supporting the inotropic function of the heart are reviewed, focusing on the emerging electrothermally artificial heart muscles (AHMs). Artificial muscle powered soft robotic devices can mimic the action of complex biological systems such as heart compression and twisting. These artificial muscles possess the ability to undergo complex deformations, aiding cardiac function while maintaining a limited weight and use of space. Two very promising candidates for artificial muscles are electrothermally actuated AHMs and biohybrid actuators using living cells or tissue embedded with artificial structures. Electrothermally actuated AHMs have demonstrated superior force generation while creating the prospect for fully soft robotic actuated ventricular assist devices. This review will critically analyze the limitations of currently available devices and discuss opportunities and directions for future research. Last, the properties of the cardiac muscle are reviewed and compared with those of different materials suitable for mechanical cardiac compression.

Mechanical Circulatory Support for Right Ventricular Failure

Right ventricular (RV) failure is associated with significant morbidity and mortality, with in-hospital mortality rates estimated as high as 70–75%. RV failure may occur following cardiac surgery in conjunction with left ventricular failure, or may be isolated in certain circumstances, such as inferior MI with RV infarction, pulmonary embolism or following left ventricular assist device placement. Medical management includes volume optimisation and inotropic and vasopressor support, and a subset of patients may benefit from mechanical circulatory support for persistent RV failure. Increasingly, percutaneous and surgical mechanical support devices are being used for RV failure. Devices for isolated RV support include percutaneous options, such as micro-axial flow pumps and extracorporeal centrifugal flow RV assist devices, surgically implanted RV assist devices and veno-arterial extracorporeal membrane oxygenation. In this review, the authors discuss the indications, candidate selection, strategies and outcomes of mechanical circulatory support for RV failure.

Concept and Design of a Novel Pulsatile Left Heart Assist Device-The PERKAT Left Ventricle System

Cardiogenic shock is associated with high mortality. Patients often require temporary mechanical circulatory support. We aimed to develop a percutaneously implantable, assist device that unloads the left ventricle (LV) in a pulsatile way. The PERkutane KATheter pump technologie (PERKAT LV) device consists of a nitinol pump chamber, which is covered by foils carrying outflow valves. A flexible tube with a pigtail-shaped tip and inflow holes represents the distal part of the pump. The system is designed for 16F percutaneous implantation. The nitinol chamber is placed in the descending aorta while the flexible tube bypasses aortic arch and ascending aorta with its tip in the LV. An intra-aortic balloon pump is placed into the chamber and connected to a console. Balloon deflation generates a blood flow from the LV into the pump chamber. During balloon inflation, blood leaves the system through the outflow foil valves in the descending aorta. Under different afterload settings using a 30 cc intra-aortic balloon pump and varying inflation/deflations rates, we recorded flow rates up to 3.0 L/min. Based on this, we believe that PERKAT LV is a promising approach for temporary LV support. The proposed design and its excellent performance give basis for in vivo tests in an animal model.

Future Devices for Percutaneous Mechanical Circulatory Support

Percutaneous mechanical circulatory support options include intra-aortic balloon pump, transvalvular axial flow pumps, left atrial to femoral artery pumping, and oxygenated right atrium to femoral artery circuits. Percutaneous mechanical circulatory support devices providing greater support have not proven superiority over the intra-aortic balloon pump. Novel counterpulsation devices target durability and ambulatory capability and direct unloading of left ventricle (LV) and right ventricle. Device innovations in transvalvular axial pumping include miniaturization of partial-support devices and development of larger self-expanding devices for near-complete LV support. Aortic entrainment pumping is a novel mode of blood displacement with potential benefits beyond reduced LV afterload.

Acute right heart failure: future perspective with the PERKAT RV pulsatile right ventricular support device

Acute right heart failure is associated with impaired prognosis in cardiogenic shock. Since most pharmacological therapies are not evaluated for the failing right ventricle, or even contraindicated, there is a need for rapid minimal invasive circulatory right heart support. The PERKAT RV is such a device for acute therapy in congestive heart failure. It reduces the central venous pooling by pumping blood from the inferior vena cava into the pulmonary artery with flow rates of up to 4 litres/min. The device was evaluated in an animal model of acute pulmonary embolism after careful in vitro tests. PERKAT RV increased cardiac output by 59% in sheep suffering from acute right heart failure. We await the first human implantation in the near future. Based on the PERKAT concept, future devolvement will also focus on left heart support.

Concept, Evaluation, and Future Perspectives of PERKAT® RV-A Novel Right Ventricular Assist Device

Right heart failure (RHF) is a life-threatening condition. Mechanical right heart support offers an option for critically ill patients. The PERKAT® RV device is designed for percutaneous implantation in acute RHF. It consists of a nitinol chamber covered by foils containing inflow valves. An outlet tube is attached to its distal tip. Using an 18F sheath, it is implanted in the inferior vena cava while the tube bypasses the right heart with its tip in the pulmonary trunk. Then, an IABP balloon is inserted in the pump chamber. Balloon deflation generates blood inflow into the chamber; during inflation, blood is pumped into the pulmonary arteries. The device is capable of achieving flow rates of up to 3.5 l/min under in vitro conditions. In vivo, we were able to increase cardiac output by 59% in a sheep model of acute pulmonary embolism. Based on this, our further research will focus on first-in-human implants.