1. ¹Cardiology/Angiology Division, Hoyerswerda Hospital, Hoyerswerda, Germany
2. ²Institute for Heart and Circulation Research, Hoyerswerda, Germany
3. ³Department for Clinical Hemostasiology and Transfusion Medicine, University of Saarland, Homburg/Saar, Germany

Correspondence: Dr J-W Park, Cardiology/Angiology Division, Hoyerswerda Hospital, Maria-Grollmuss-Strasse 10, 02977 Hoyerswerda, Germany. E-mail: jai-wunpark@t-online.de

Received 11 August 2005; Revised 18 November 2006; Accepted 30 November 2006; Published online 16 August 2007.

Abstract

Despite the proven clinical efficacy of phosphodiesterase inhibitors in the treatment of erectile dysfunction (ED), some patients do not respond to the medication. By means of nailfold capillary microscopy in patients with concomitant coronary artery disease (CAD) and ED, it was evaluated whether the extent of microvascular dysregulation predicts the responsiveness to tadalafil (TAD) in terms of erectile function. The ED of each patient was assessed by the International Index of Erectile Function (IIEF). Patients presenting both, documented CAD and ED, showed a significantly reduced capillary red blood cell velocity (v_RBC) at rest and after 3 min of ischemia compared with age-matched controls. At 2 h after intake of 20 mg of TAD, a significant increase of v_RBC at rest as well as during postischemic hyperemia was found. Patients who reported no improvement of their ED after the use of TAD demonstrated no changes in the duration of postischemic (DpH) hyperemia, or even a reduction of the DpH. The majority of the patients, who reported at least one successful sexual intercourse due to TAD, had a prolongation of DpH. We conclude that assessment of microvascular regulation by nailfold capillary microscopy can predict the probability of a treatment failure with phosphodiesterase inhibitors in patients with ED. Moreover, as endothelial dysfunction is the common underlying pathophysiological process of ED and cardiovascular diseases, the test may help to identify patients at risk for the development of atherosclerosis and following cardiovascular events.