Association of Hyperbaric Oxygen Therapy with Platelet Reactivity in Patients with Advanced Peripheral Arterial Disease: A Prospective Observational Study

Objective: Peripheral arterial occlusive disease (PAOD) is characterized by impaired tissue perfusion, chronic ischemia, and increased platelet reactivity. Hyperbaric oxygen therapy (HBOT) is used as adjunctive treatment in advanced PAOD, but its effect on platelet function remains insufficiently studied. This study examined the association between HBOT and platelet aggregation. Methods: This prospective observational study included 90 patients with Fontaine stage IV PAOD and chronic ulceration, assigned to an HBOT group (n = 60) or waiting-list control group (n = 30). Patients were predominantly male; mean age was 66.82 ± 9.42 years in the study group and 63.00 ± 8.31 years in controls, and diabetes mellitus was present in 55.0% and 63.3%, respectively. Prior revascularization included open surgery in 33.3% and 30.0%, endovascular treatment in 36.7% and 43.3%, and no option for revascularization in 30.0% and 26.7%, respectively. HBOT was administered over 4 weeks (20 sessions, 2.0–2.5 ATA). Platelet aggregation was measured by impedance aggregometry using arachidonic-acid-induced aggregation (ASPI), adenosine-diphosphate-induced aggregation (ADP), and thrombin-receptor-activating peptide-induced aggregation (TRAP) agonists. Changes were analyzed using generalized estimating equation models adjusted for antiplatelet therapy, diabetes mellitus, smoking, and C-reactive protein (CRP). Results: Significant group × time interactions were observed for all platelet activation pathways, indicating greater reductions in the HBOT group than controls: ASPI (β = −290.5; p < 0.001), ADP (β = −243.6; p < 0.001), and TRAP (β = −330.9; p < 0.001). No significant change was observed in controls. HBOT was associated with reduced pain intensity, while CRP and platelet-to-lymphocyte ratio (PLR) remained stable. Ulcer size showed no significant change after 4 weeks. Conclusions: In patients with PAOD, HBOT was associated with reduced platelet reactivity independent of antiplatelet therapy. Further randomized studies are needed to determine its clinical significance.