First-in-Human Study Uses Micro-Oxygen Sensors During Endovascular Therapy for Limb-Threatening Ischemia

May 22, 2015—Miguel F. Montero-Baker, MD, et al published the results of the first-in-human “Si Se Puede” study to assess the feasibility of using micro-oxygen sensors (MOXYs; Profusa, Inc) in the feet of patients with limb-threatening ischemia during endovascular therapy in the Journal of Vascular Surgery (2015;61:1501–1510). The background of the study is that in such patients, there can be uneven patterns of perfusion in the foot, which makes it challenging to determine adequate topographic perfusion by angiography alone.

As reported in the Journal of Vascular Surgery, the investigators tested the use of MOXYs to report dynamic relative oxygen indices and tissue oxygen concentration from multiple locations on the foot. A prospective, 28-day, single-arm, observational study was performed in 10 patients who underwent endovascular therapy for limb-threatening ischemia (50% male; 30% Rutherford class 4, 70% Rutherford class 5; mean age, 70.7 years [range, 46–90 years]).

Four MOXYs were injected in each patient at least 24 hours before therapy: one in the arm and three in the foot intended for treatment. A custom detector on the skin surface was used to measure the signals from the MOXYs continuously and noninvasively. The optical signal from the MOXYs corresponded to tissue oxygen concentration, and the oxygen data were collected throughout the revascularization procedure. Oxygen data collection and clinical evaluation were performed immediately postoperatively and on days 7, 14, 21, and 28.

MOXYs were compatible with intraoperative use in the interventional suite and postoperatively in an office setting. The sensors were read successfully 206 of 212 times (97.2%) in all patients in the course of the study. In nine of 10 procedures, at least one of the three MOXYs showed an immediate change in the dynamic relative oxygen index, correlating to deployed therapy. No adverse events occurred related to the MOXY materials, and there was a statistically significant increase in the concentration of oxygen in the foot postoperatively.

This MOXY approach appeared to be safe in these patients and effective in reporting local tissue oxygen concentrations over the course of 28 days, and further testing is needed to determine its potential effect on clinical decision making both acutely and as a surveillance modality, concluded the investigators in the Journal of Vascular Surgery.