AbstractTo evaluate whether preventive treatment can modify endothelial and oxidative biomarkers of vascular disease risk in patients with high-frequency episodic and chronic migraine. In this observational, prospective pilot study, 88 prophylactic treatment-naïve patients with episodic and chronic migraine and 56 healthy sex/age matched controls underwent ultrasonography exams and blood tests at baseline, and again in the migraine patients after 3 months’ treatment with metoprolol or topiramate. Biomarkers for endothelial function and oxidative stress were analyzed. At baseline, patients with migraine in the low-frequency episodic group had differences exclusively in nitrates 17.6 versus 27.33 µM; p = 0.046 compared to the controls. However, when comparing the group comprised of patients with high-frequency episodic migraine and chronic migraine versus controls, statistically significant differences appeared in hsCRP 2.68 versus 1.64 mg/dL; p = 0.049, vWF antigen (133% vs. 110%; p = 0.020, vWF activity (111% vs. 90%; p = 0.010) and isoprostane levels (181 vs. 238 µM; p = 0.05). Only in the chronic migraine subgroup did we found statistically significant differences in CIMT (0.60 vs. 0.54 mm; p = 0.042) which were significantly greater than in the controls. After treatment, patients who respond to preventive treatment exhibited significantly higher levels of nitrates (24.2–13.8 µM; p = 0.022) and nitrites (10.4–3.43 µM; p = 0.002) compared than non-responders. Moreover, biomarker levels improved in treatment-responsive patients with migraine; hsCRP levels decreased from 2.54 to 1.69 mg/dL (p < 0.05), vWF activity levels decreased from 124 to 103 IU/dL (p = 0.003) and prothrombin activity decreased from 1.01 to 0.93 (p = 0.01). These differences were also observed in the high-frequency and chronic migraine subgroup and reach statistical significance in the case of hsCRP, which decreased from 2.12 to 0.83 mg/dL (p = 0.048). Patients with migraines have differences in biomarker levels compared to controls, suggesting endothelial and oxidative dysfunction. The greatest differences in biomarker levels compared to controls are observed in migraine patients in the high-frequency and chronic migraine subgroups. Based on our results, preventive treatment is capable of modifying markers of endothelial dysfunction and oxidative stress in migraine patients, even in cases of chronic and high-frequency migraine.