A Novel Implantable Inferior Vena Cava Sensor: Validation of Remote Monitoring Derived Area with Computerized Tomography

Intravascular volume shifts assessed by inferior vena cava (IVC) size are associated with adverse outcomes and hospitalization in patients with heart failure (HF). A novel implantable IVC sensor was developed to provide remote daily assessment of IVC area and its collapsibility index (in response to respiration) as a measure of volume status in patients with HF. Daily assessment of these biomarkers of volume status in HF enables early detection of fluid overload and proactive HF management. This study was designed to validate the accuracy of IVC area derived from the sensor as adjudicated against concurrent Computerized Tomography (CT) recorded at 3-months after implantation (N=56; across two global clinical studies) using a validated graphical user interface (GUI), which demonstrated 90% confidence and reliability in CT annotation. CT-derived IVC area was compared to sensor-derived IVC area. The results demonstrated strong correlation (r=0.99, p<0.001), excellent agreement, with a mean absolute error of 12.94mm2 (relative error: 3.35%), and Bland-Altman analysis demonstrating a mean difference of 5.85mm2 with narrow limits of agreement (-24.0 to 35.7 mm2). These findings confirm the high accuracy of the remotely transmitted data, supporting its potential role in continuous, ambulatory congestion monitoring in HF. This study builds upon previous bench and preclinical findings, reinforcing the robustness of the system and suggest that this sensor can be potentially integrated clinically for the management of HF.