Endocrine Abstracts

Background and Aims: Studies have revealed increased vascular mortality, particularly cerebrovascular mortality in hypopituitary adults. Cranial radiotherapy has been implicated. This study was designed to assess the impact of cranial irradiation upon cerebrovascular function in patients with pituitary disease.

Methods: Three groups were studied: - Group 1- (n=12), patients with pituitary disease who have had cranial radiotherapy, Group 2- (n=10), patients with pituitary disease who have not had cranial radiotherapy and Group 3- (n=24),normal controls.

Patients with acromegaly, Cushing’s and idiopathic pituitary disease were excluded.

The blood velocity in the middle cerebral artery (MCA) was assessed with a Scimed QVL 120 transcranial doppler. Velocities were measured whilst breathing air and then after 3-minute inhalation of 5% carbon dioxide (CO₂). Using these results the vasomotor reactivity was calculated as the change in velocity in the MCA per unit change in CO₂ before and after inhalation. Expired CO₂ concentration was determined using a Datex TC6 capnograph. The study was approved by Local ethics committee.

Results: Independent t-tests were performed with SPSS ver 10.0, comparing patient group with controls. There was a significant difference in the vasomotor reactivity between the group 1 and group 3, mean difference 14.87 (95% C.I. 5.40–24.35, P=0.003). No significant difference between groups 2 and 3, mean difference 9.26 (95% C.I. 24.03–5.40, P=0.210). No significant difference between groups 1 and 2, mean difference 5.61 (95% C.I. −3.73–14.45, P=0.200).

Conclusion: Cranial irradiation possibly contributes to reduced cerebral vasomotor reactivity in patients with pituitary disease.