Orthostatic hypotension and vasodilatory peptides in bronchial carcinoma

To determine whether inappropriately secreted vasodilatory peptides have a role in the pathogenesis of orthostatic (postural) hypotension, a recognised paraneoplastic effect of bronchial malignancies usually attributed to immune mediated destruction of autonomic ganglia.

Serum concentrations of three vasodilatory peptides, atrial natriuretic peptide (ANP), vasoactive intestinal polypeptide (VIP) and calcitonin gene related peptide (CGRP), were measured in 111 patients with bronchial carcinoma and 35 controls prospectively screened for orthostatic hypotension (> 20 mmHg drop in systolic blood pressure on repeated occasions on standing from the supine position) and in whom other causes of this condition were excluded.

Twenty two (20%) patients with carcinoma and two (6%) controls had orthostatic hypotension according to the criteria used. Serum concentrations of ANP, VIP and CGRP were elevated above normal in, respectively, 25 (23%), 10 (9%) and eight (7%) patients with carcinoma and in six (18%), zero and three (9%) controls. There was no correlation between orthostatic hypotension and concentrations of any of the vasodilatory peptides.

Elevated serum concentrations of ANP and CGRP were no more frequent in subjects with bronchial carcinoma than in controls and could not be attributed to the tumour, although there was a possible association for VIP. Orthostatic hypotension was more common in patients with carcinoma, but there was no evidence that the peptides measured played a role in its pathogenesis.