gms | German Medical Science

Background: Current methods evaluating tissue ischemia are based mainly on evaluating blood flow and not blood perfusion. This is suitable for evaluating big artery disease, however, blood flow evaluation is less valuable in below the knee (BTK) arteries. To this day, there is no golden standard method to measure blood perfusion intraoperatively. The aim of the trial was to evaluate the feasibility of NIRS in measuring perfusion changes during chronic total occlusion (CTO) revascularization in BTK arteries. Primary hypothesis stating that blood perfusion increase could be detected using NIRS during revascularization of BTK arteries was placed. Moreover, it was hypothesized that an intraoperative increase of NIRS rSO2 could predict wound healing.

Methods: A prospective observational study was performed. During the endovascular revascularization procedure, blood perfusion changes were measured using two NIRS sensors placed near the wound. Baseline was recalculated to a third sensor placed on the chest. Postoperative angiographies were performed and afterwards assessed by an independent physician. Wound healing was evaluated during follow-up visits 30 days post revascularization.

Results: The study enrolled 30 patients with chronic limb threatening ischemia, occluded below the knee arteries, Rutherford 5. Mean age was 74.7 ± 11.2 years, 16 (53%) of the patients had diabetes mellitus, 10 (33%) had end-stage renal disease. A statistically significant NIRS rSO2 increase was observed on sensors near the wound after the revascularization (paired samples T-test, p=0.001). Technical angiographic success was independently evaluated as suboptimal in 12 patients and optimal in 18 patients. NIRS rSO2 increase difference between the two groups was statistically insignificant. Follow-up visits included 27 patients. Wound healing was evaluated as poor in 9 patients and good in 18 patients. Comparing good wound healing group with poor wound healing group intraoperative NIRS rSO2 increase difference was statistically significant, p=0.017.

Conclusion: The study confirmed blood perfusion increase could be detected using NIRS during revascularization of BTK arteries. A statistically significant NIRS rSO2 increase after the revascularization was found. An intraoperative increase of NIRS rSO2 proved to predict wound healing results. In this setting, NIRS rSO2 increase as a predictive marker for wound healing outperformed independent angiographic evaluation of revascularization.