Effects of hyperbaric oxygen on vascular endothelial function in patients with slow coronary flow

Background: To improve therapy for slow coronary flow (SCF), the effects of hyperbaric oxygen (HBO) therapy on vascular endothelial function in SCF patients is the focus of this investigation. Methods: Ninety-eight patients who exhibited chest discomfort were retrospectively analyzed, and diagnosed with SCF by coronary artery angiography at the Third Hospital of Hebei Medical University, Shijiazhuang, China from 2014 to 2016. The patients were divided into two groups according to the following treatment: HBO group (n = 48) and the control group (n = 50). Patients in the control group were administrated with conventional treatment, while those in the HBO group were administrated HBO therapy for 4 weeks in addition to conventional treatment. To evaluate the effects of HBO on vascular endothelial functions, plasma levels of nitric oxide (NO), calcitonin gene-related peptide (CGRP), endothelin-1 (ET-1), high sensitivity C-reactive protein (hsCRP) as well as endothelial-dependent flow-mediated vasodilation (FMD) of the brachial artery were measured in both groups before and after their respective treatments. Results: There were no significant differences in plasma levels of NO, ET-1, CGRP, hsCRP nor in FMD measurements between the two groups before treatment (p > 0.05). Moreover, the levels of all the parameters measured showed no significant changes before and after treatment in the control group. However, when comparing the control group, FMD and plasma NO and CGRP levels were significantly increased in the HBO group after treatment (p < 0.01), whereas hsCRP and ET-1 levels decreased dramatically (p < 0.001). Conclusions: The HBO treatment in addition to conventional therapy may significantly improve the vascular endothelial function in SCF patients.