The effects of thromboxane A2 inhibition (picotamide) and angiotensin II receptor blockade (losartan) in primary Raynaud's phenomenon.

Objectives: To assess the role of thromboxane A2 and of angiotensin II in patients with primary Raynaud's phenomenon.

Design: After an eight-day run-in period, the patients were enrolled in a single-blind, cross-over, study.

Setting: Patients were examined at the Ambulatory for Microcirculatory Diseases of the Clinic of Internal Medicine, University Hospital, Verona.

Subjects: Fifteen subjects affected by primary Raynaud's phenomenon were included.

Main Outcome Measures: A piezoelectric plethysmography to evaluate the distensibility of the digital arteries as the ratio between peak time (PT) and total time (TT), and an oscillometric blood pressure recorder were used after the run-in period, and after a two-week course of picotamide (300 mg b.i.d., i.e. two times daily) or losartan (12.5 mg once daily) with an interval of a week of placebo between the active treatments. The tests were performed after every treatment in basal condition and during mental stress. The patients reported in a diary the number and the severity (from 0 to 4 +) of the vasospastic crises.

Results: The change in TP/TT ratio appeared statistically significant only after losartan treatment, both in basal condition and during mathematical stress. Both pharmacological treatments, with respect to placebo, showed an improvement of the scores, derived from the number and severity of vasospastic attacks, but only the therapy with losartan determined a statistically significant improvement.

Conclusions: The inhibition of the type 1 receptor for angiotensin II seems highly effective in the reduction of the vasospastic crises in the subjects with primary Raynaud's phenomenon. According to our experience, losartan could be used more extensively in the treatment of these patients besides arterial hypertension.