Safety and Feasibility of an Implanted Inferior Vena Cava Sensor for Accurate Volume Assessment: FUTURE-HF2 Trial.

Background: A novel implantable sensor has been designed to measure the inferior vena cava (IVC) area accurately so as to allow daily monitoring of the IVC area and collapse to predict congestion in heart failure (HF).

Methods: A prospective, multicenter, single-arm, Early Feasibility Study enrolled 15 patients with HF (irrespective of ejection fraction) and with an HF event in the previous 12 months, an elevated NT-proBNP level, and receiving ≥ 40 mg of furosemide equivalent. Primary endpoints included successful deployment without procedure-related (30 days) or sensor-related complications (3 months) and successful data transmission to a secure database (3 months). Accuracy of sensor-derived IVC area, patient adherence, NYHA classification, and KCCQ were assessed from baseline to 3 months. Patient-specific signal alterations were correlated with clinical presentation to guide interventions.

Results: Fifteen patients underwent implantation: 66 ± 12 years; 47% female; 27% with HFpEF, NT-ProBNP levels 2569 (median, IQR: 1674-5187, ng/L; 87% NYHA class III). All patients met the primary safety and effectiveness endpoints. Sensor-derived IVC areas showed excellent agreement with concurrent computed tomography (R² = 0.99, mean absolute error = 11.15 mm²). Median adherence to daily readings was 98% (IQR: 86%-100%) per patient-month. A significant improvement was seen in NYHA class and a nonsignificant improvement was observed in KCCQ.

Conclusions: Implantation of a novel IVC sensor (FIRE1) was feasible, uncomplicated and safe. Sensor outputs aligned with clinical presentations and improvements in clinical outcomes. Future investigation to establish the IVC sensor remote management of HF is strongly warranted.