A clinical investigation recently
published in the journal Cephalalgia, the official journal
of the International Headache Society, suggests that migraine patients may
exhibit a systemic pathophysiological alteration. The study, entitled “Abnormal
cardiovascular response to nitroglycerin in migraine”, was conducted by Dr. Willebrordus
PJ van Oosterhout, from Leiden University Medical Centre, Department of
Neurology, Leiden, The Netherlands.
Nitroglycerin
(NTG) is a potent vasodilator and is known to induce migraine attacks in
migraine patients. Because of its vasodilating properties, NTG is used in
cardiovascular research to test cardiovascular adjustments in face of changes
in blood pressure secondary to blood venous pooling. For example, NTG is used
to test baroreflex function in individuals with vasovagal syncope, which is more
common in migraine patients.
Dr. van
Oosterhout and colleagues assessed cardiovascular parameters through
photopletismography (blood pressure, heart rate, stroke volume, cardiac output,
peripheral resistance) before (-10 min.), during the infusion of NTG
intravenously (20 min.), and after the NTG infusion (10 min.) They compared
differences between migraine patients who had NTG-triggered attacks and healthy
people. The presence of vasovagal syncope was assessed as well.
Ten healthy
participants and 16 migraine patients were included in the study. Thirteen out
of 16 patients (81.3 %) had migraine attacks following NTG infusion, against
none from the control group. No vasovagal syncope was provoked. Migraine
patients showed higher heart rate response to NTG infusion. In a subgroup
analysis with migraine patients group split into patients with early-onset
attacks (those whose attacks occurred < 270 min after NTG infusion) or with
late-onset attacks (> 270 min.), stroke volume and cardiac output were
reduced in both migraine groups compared to healthy control group, with more
pronounced reductions in the early-onset migraine attacks group.
The authors’
interpretations of these data are cautious, as the study was underpowered with
a small sample. In a speculative tone, Dr van Oosterhout says: “The enhanced
response of the systemic circulation to nitroglycerin in migraineurs suggests
that the systemic vasculature is more susceptible to its (vasodilatory)
effects”. And follows: “Sensitivity to nitric oxide (NO) may be enhanced,
possibly due to higher perivascular concentrations of NO synthase”. Finally,
although no participant had vasovagal syncope, the authors do not rule out a
common susceptibility of migraine attacks and vasovagal syncope, as some
patients in this study had also experienced vasovagal syncope in life.
Journal article: https://journals.sagepub.com/doi/10.1177/0333102419881657
Source: https://myfusimotors.com/2019/12/28/on-nitroglycerin-cardiovascular-homeostasis-and-bam-migraine/
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