Feasibility of a novel implantable device to provide heart failure therapy and left atrial pressure monitoring in a chronic animal study

Abstract Introduction Pulmonary Artery Pressure Monitoring (PAPM) has been shown to reduce rehospitalization in heart failure (HF) patients. Interatrial Shunting Therapy (IST) is in clinical studies for similar purposes. However, current available devices provide either PAPM or IST, but not both in the same device. Purpose A novel implantable device system has been developed to provide IST and Left Atrial Pressure (LAP) monitoring. The system consists of an implant, a delivery system, and an external Monitoring Unit (MU). The MU works with the battery-less MEMS pressure sensor, as part of the implant, to provide the measured LAP to user. The aim of this study is to assess the feasibility of the system and accuracy of measured LAP as compared to the Swan-Ganz measured Pulmonary Capillary Wedge Pressure (PCWP) in a chronic canine study. Methods The implant is designed to integrate the interatrial shunting and LAP sensing. It is designed to be placed on the atrial septum with the fixation by three pairs of nitinol anchors. The device was implanted in 10 healthy dogs (Labrador, 30-35 Kg), with 4 observed for 1 month and 6 for 3 months, all under general anesthesia. Procedure success, safety outcome, shunt patency (via TEE) and pressure accuracy were evaluated. In order to achieve various pressure levels, phenylephrine (0.05-2.00 mg) was injected during implant and at the end of each follow up (FU) before termination. Pressure waveforms of PCWP and LAP from the device sensor were recorded for more than 10 seconds simultaneously by PowerLab (PLC01) and MU respectively. Correlation and agreement between LAP and PCWP from implant and FU were assessed with Pearson’s correlation analysis and Bland-Altman plots. Results The implant was successful in all dogs and the shunt was patent at 1 or 3 months. No device related adverse event was observed during FU periods and gross anatomical findings at termination at 1 or 3 months were all acceptable. Pressure points were obtained at each time for each dog, with a total of 42 pairs of pressure measurements ranging from 0 to 22 mmHg from all dogs. Fig. 1a shows an example of the gross anatomy of encapsulation of the device by a thin layer of endothelium at 3 months. Representative simultaneous waveform recordings, correlation and Bland-Altman plot are shown in Fig.1b-d. The PCWP and LAP measurements correlated well (R²=0.87), with an average difference of 0.33±1.80 mmHg. In the Bland-Altman plot, 40 of 42 pairs fell inside the 95% limit of agreement, indicating good agreement between PCWP measured by Swan-Ganz and LAP by the MEMS pressure sensor of the device. Conclusions This preliminary chronic canine study demonstrated the feasibility of this implantable device and the accuracy of LAP from the MEMS sensor as compared to PCWP. Further studies are warranted. This novel device with interatrial shunting therapy and hemodynamics may provide clinicians with more options for managing HF patients.Fig.1