# Real-Time Perfusion Assessment with Hyperspectral Imaging After Revascularization in Peripheral Artery Disease

## TL;DR

This study compares hyperspectral imaging and transcutaneous oxygen pressure to assess tissue perfusion after revascularization in peripheral artery disease patients.

## Contribution

The study evaluates HSI's validity against TcPO2 in a larger cohort with repeated measurements and clinical outcomes.

## Key findings

- StO2 and NIR showed significant perfusion improvement after revascularization.
- TcPO2 improved significantly and correlated with clinical outcomes, unlike HSI parameters.
- Many HSI measurements showed no improvement despite successful revascularization and higher TcPO2.

## Abstract

Background/Objectives: Hyperspectral imaging (HSI) facilitates noninvasive assessment of tissue perfusion in patients with peripheral arterial disease. However, available studies are either based on small cohorts and provide no comparison to standard methods or only one-time measurements. Methods: In this prospective cohort study, assessment of tissue perfusion with transcutaneous oxygen pressure (TcPO2) measurement and HSI before (1 day) and after revascularization (1–3 days) in patients with Rutherford category 3–6 was performed. The primary endpoint was change in tissue perfusion evaluated with the different methods. HSI and TcPO2 were correlated with clinical improvement after revascularization. Results: Significant improvement in the perfusion was detected by tissue oxygenation in the microcirculation (StO2; improvement +12%, mean difference 5 ± 15.9, p < 0.001) and near-infrared spectroscopy (NIR; improvement +9%, mean difference 3.7 ± 7.1, p < 0.001), but not with the tissue hemoglobin index (THI; mean difference +0.8 ± 10.3, p = 0.428). A high number of worse or unchanged HSI measurements despite successful revascularization was detected. A significant improvement of TcPO2 after revascularization (mean difference +16.2 ± 27.7 mmHg, p < 0.001), consistent with clinical improvement, was detected. No correlation of the HSI parameters with TcPO2 or clinical symptoms could be seen. Conclusions: Significant improvement of StO2, NIR and TcPO2 values was detected after successful revascularization; however, no correlation of HSI parameters with TcPO2 or clinical results could be observed. Furthermore, the substantial rate of lower or unchanged HSI parameters despite clinical improvement and higher TcPO2 values calls the validity and clinical relevance of TIVITA®-based HSI measurements for postoperative tissue perfusion improvement into question.