Phosphodiesterase type 5 inhibition is a novel therapeutic option in Raynaud disease

Raynaud disease (RD) is a common disorder affecting 3% to 5% of the healthy population, and occurs in more than 90% of patients with connective tissue diseases. The therapeutic options remain limited, particularly in patients with secondary RD due to connective tissue disease. Theoretical considerations lead to the expectation that phosphodiesterase type 5 inhibitors may improve clinical symptoms and digital blood flow in patients with RD.

We conducted an open-label pilot study in 40 patients with RD, 33 (82%) of whom had secondary and 7 (18%) of whom had primary RD. Digital blood flow was measured by laser-Doppler flowmetry at room temperature and during the cold-exposure test before medical treatment, 1 hour after the initial intake, and after 2 weeks of continuous treatment (10 mg twice a day) with the novel phosphodiesterase type 5 inhibitor vardenafil. Clinical symptoms were recorded by a patient questionnaire and summarized as the Raynaud condition score.

Laser-Doppler flowmetry revealed that vardenafil improved digital blood flow in 28 (70%) patients, whereas 12 (30%) did not respond. In individuals responding, digital blood flow significantly increased by a mean +/- SEM of 21.0% +/- 4.9% and 30.0% +/- 5.7% at 1 hour and 2 weeks of treatment at room temperature, respectively, and by 18.8% +/- 4.4% and 35.1% +/- 7.5% at 1 hour and 2 weeks during the cold-exposure test, respectively (P < .01 for all). Consistently, clinical symptoms improved in 27 (68%) of the 40 patients, and the Raynaud condition score declined from a mean +/- SEM of 5.05 +/- 0.38 to 3.54 +/- 0.31 (P < .001).

Our data indicate that phosphodiesterase type 5 inhibition significantly improves peripheral blood flow and clinical symptoms in a large subset of patients with RD and, thus, may provide a novel therapeutic approach in such individuals.