In-Vivo Optical Spectroscopy (INVOS) as a Prognostic Tool for Peripheral Artery Disease During Endovascular Intervention: A Pilot Study.

Introduction: Peripheral arterial disease (PAD), including intermittent claudication (IC) or critical limb ischemia (CLI), can be treated with endovascular revascularization; however, tools for intraoperative prognostication are limited. The In-Vivo Optical Spectroscopy (INVOS) system, a non-invasive near-infrared spectroscopy device, measures tissue oxygenation. This pilot study aims to investigate the use of INVOS during endovascular surgery for PAD as a prognostic tool for endovascular PAD treatment. This study is intended as a feasibility and hypothesis-generating pilot, rather than one designed to draw definitive conclusions.

Methods: Thirty patients with PAD undergoing endovascular treatment were prospectively enrolled. In-Vivo Optical Spectroscopy sensors were applied to the treated foot preoperatively. Measurements were recorded preoperatively, postoperatively, and at 1, 2, and 3 hours post-surgery. Raw INVOS values and INVOS/systolic blood pressure (SBP) ratios were calculated and normalized to baseline values to determine fold changes. Clinical outcomes were assessed at 30 days.

Results: No significant changes in raw INVOS or SBP values were observed before or after the procedure in both IC and CLI groups. However, the normalized INVOS/SBP ratio was significantly higher in IC patients at 1 and 2 hours postoperatively (p<0.05). A fold change greater than 1.25 was associated with better clinical outcomes, including fewer complications and higher rates of patient- and physician-reported improvement.

Conclusion: An INVOS/SBP ratio fold change greater than 1.25-fold is associated with improved outcomes following endovascular intervention for PAD. In-Vivo Optical Spectroscopy may serve as a valuable intraoperative prognostic tool, particularly in IC patients. Further studies are needed to validate these findings.Clinical ImpactThe clinical impact of the current work is to improve the knowledge in the application of INVOS measurements peri operative in clinical practices and improve patients care. Post operative surveillance with INVOS could be used to confirm surgical success. INVOS ratio lower than 1.25-fold after first revascularization should be reassessed and improve blood flow towards the limb. Although limited, this pilot study shows that the use of INVOS can be an adjuvanted tool in monitoring surgical outcomes in patients with PAD.