Abstract 303: Monitoring Tissue Oxygen Dynamics With A Novel Implantable Hydrogel Sensor In Patients With Pad

Abstract

Objective: Tissue perfusion measurement remains a fundamental challenge in management of peripheral arterial disease (PAD) patients. Better measurement of baseline and dynamic changes after revascularization would aid clinical judgement. The Wireless Lumee® Oxygen System represents a novel approach to tracking tissue oxygen via a subcutaneous hydrogel that provides noninvasive optical oxygen measurements. This study’s objective was to assess the correlation of the Lumee sensor with transcutaneous oximetry (tcpO2) in PAD patients. Methods: The Lumee® Oxygen System is a subcutaneously placed hydrogel (0.5x0.5x5mm). Optical signals are captured with a skin surface reader sensing extravascular oxygenation. A pilot study assessed in vivo performance with inclusion criteria of peripheral arterial disease (Rutherford I-IV). Sensors were injected in the arm and foot and oxygenation measured before, during, and after proximal blood pressure cuff inflation (Figure) and Buerger’s Test modulation. The correlation (R) of oxygenation between tcpO2 and Lumee® was assessed following sensor placement at 2, 10, 90, 180, and 365 days. Results: Eleven subjects had 148 occlusion modulations over 199 days. Mean age was 67 years (range: 55-88), with 9% females, 45% White and 55% Black Race, Rutherford class I: 36%, II: 36%, III:27%. The median ABI was 0.83 (IQR0.69-1.14). In the arm, modulation was 56.9±24.6% (Lumee) and 84.7±9.2% (tcpO2), R:0.81. In the foot, modulation was 63.4±22.7% (Lumee) and 80.4±15.5% (tcpO2), R:0.79. No injection related adverse events occurred. Conclusion: Occlusion related changes in tissue oxygen can be detected by both tcpO2 and the Lumee sensor which strongly correlate in both the arm and foot. This pilot phase study supports expansion of the trial. The Lumee sensor shows promise for future evaluation of tissue oxygenation in PAD patients, which could be used to assess changes in tissue oxygenation over time and following revascularization.