Abstract text (incl. figure legends and references)

Background: Migraine is recognized as a disorder of calcitonin gene-related peptide (CGRP) pathway. CGRP test can discriminate migraine from non-migraine using CGRP-induced headache (CGRP-IH) and cerebral hemodynamic changes. We test hypothesis that hemodynamic changes related to cerebral vascular responses could discriminate between migraineurs prone to CGRP effects.

Methods: We included two groups of participants. Group A consisted of twenty healthy participants (nine females aged 37.0 ± 2.8 years, 11 males aged 41.8 ± 7.6 years). Group B consisted of twenty participants with migraine (15 females aged 41.9 ± 9.9 years, 5 males aged 38.2 ± 9.2 years). Responses in middle cerebral artery (R MCA) and posterior cerebral artery (R PCA) were determined by measuring mean arterial velocity (vm) and calculating difference between vm during CGRP stimulation and basal vm. The Et-CO2 was measured by an infrared capnograph. CGRP-IH, MO and MA were detected according to the International Classification of Headache Disorders third edition. We calculated the responses (R) of vm MCA, vm PCA, Et-CO2, HR, and MAP as differences between measuring points.

Results: We found significant differences in the frequency of CGRP-IH between migraineurs and non-migraineurs (p=0.001). We found linear positive relationship between responses R2 MCA and R2 Et-CO2 (r=0.477, p=0.002) and significant difference between product of R2 MCA Et-CO2 of migraineurs (30.3±8.7 cms-1 mmHg) and controls (4.9±2.8 cms-1 mmHg) (p=0.008).The AUC for product R2 MCA Et-CO2 is 0.750 (95% CI 0.598-0.902 p=0.007).

Conclusions: CGRP- test might discriminate between migraine susceptible to CGRP from non-susceptible CGRP migraineurs and non-migraineurs. It could be used to predict response to anti-CGRP monoclonal antibodies.