Epicardial injection using a miniature crawling robotic device through a subxiphoid approach

Abstract

Objective: Cardiac cell transplantation therapy has been rapidly developed as an effective treatment for postinfarction heart failure. However, the present strategy requires a full or partial sternotomy to expose the heart. For dedicated minimally invasive epicardial injection, we have developed a miniature crawling robot (HeartLander) that navigates on the surface of a heart. We tested the epicardial injection with the HeartLander using a beating porcine heart through a closed chest subxiphoid approach.

Methods: HeartLander consists of two articulated modules that adhere to the epicardium using suction. The modules are each 6.5 mm tall and 8 mm wide, and include two working channels for instrumentation. Vacuum pressure and wire actuation for inchworm-like locomotion are provided through the tether of the robot. In 5 porcine preparations, the device was inserted into the pericardial space through a subxiphoid approach. Visualization was achieved with an on-board camera and a fluoroscopy. Epicardial injection on the ventricular wall was performed with a dedicated injection needle device through the working port of the robot. A dye was used for the injection mimicking cell transplantation therapy. The blood pressure and electrocardiogram were monitored. The heart was excised and examined after the tests.

Results: Several injections into all around ventricles (i.e. anterior, lateral, posterior ventricular wall) were successfully accomplished in all cases. The on-board camera provided adequate visualization of intrapericardial landmarks. The fluoroscopy was useful to realize the spatial location of the robot. No fatal arrhythmia and unexpected bleeding were noted during the trial. Successful dye injections were confirmed with macroscopy after excising the heart. There were no injuries to the heart and surrounding structures due to the robot locomotion. A histological study verified no epicardial damage caused by the locomotion.

Conclusions: The HeartLander demonstrated successful epicardial injection on a beating porcine heart through a closed chest subxiphoid approach. This approach will facilitate the cardiac cell transplantation therapy in the field minimally invasive surgery.