LETTER TO THE EDITOR
Impaired vascular reactivity in patients with erectile dysfunction
Piero Montorsi, MD
Institute of Cardiology, University of Milan, Centro Cardiologico Mozino, IRCCS, Milan, Italy 20132
Alberto Briganti, MD and
Andrea Salonia, MD
Department of Urology and Sexual Medicine, Università Vita Salute, Ospedale San Raffaele, Milan, Italy 20132
Alberto Margonato, MD
Department of Cardiology, Università Vita Salute, Ospedale San Raffaele, Milan, Italy 20132
Francesco Montorsi, MD
Department of Urology and Sexual Medicine, Università Vita Salute, Ospedale San Raffaele, Via Olgettina, 60, Milan, Italy 20132
(Email: montorsi.francesco{at}hsr.it).
In the January 21, 2004 issue of the Journal, Kaiser et al. (1) reported about endothelial function in patients with erectile dysfunction (ED) and no vascular risk factors. They found this group as having significantly less vasodilation to both ischemia (endothelium dependent) and nitroglycerin (endothelium independent) stimuli than normal subjects. These data led the investigators to conclude there was a peripheral vascular defect occurring before the development of overt vascular disease, thus reinforcing the concept of ED as an early marker for systemic vascular disease (1).
We believe that one major point needs clarification. Patients were classified as having ED according to the International Index of Erectile Function (IIEF) (2). This is a 15-item validated self-administered questionnaire that explores five domains of sexual function: erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction. Erectile function is specifically addressed by six questions, 1, 2, 3, 4, 5, and 15, which form the so-called "erectile function domain" of the questionnaire. Each question is scored 0 (or 1) to 5 with a minimum and maximum score of 1 and 30, respectively. Erectile dysfunction is defined as any value <26. Below this cut-off point, ED is further defined as mild (22 to 25), mild-to-moderate (17 to 21), moderate (11 to 16), and severe (<10) (3). In the Kaiser et al. (1) study, "normal" subjects had a mean (±SD) score of the IIEF erectile function domain of 21.3 ± 5.3. Assuming a normal distribution, this means that almost 80% of normal subjects were below the cut-off for ED, of whom 40% likely had an IIEF score <20 (mild-to-moderate ED) and 10% <15 (moderate ED). Thus, many "normal" subjects were actually impotent, although to a lesser degree than the true ED group. However, penile color Doppler sonography (the only test that might have further differentiated the two groups) was not performed in normal subjects, and this makes any comment conjectural.
If this observation holds true, differences in the vascular response between groups should be reconsidered. In fact, if the dilation response of "normal" patients with ED is combined with dilation response of the real ED group, one would expect to obtain a higher mean value of percent vascular dilation. For example, percent dilation at 60 s after cuff release was 2.4 ± 0.5 versus 3.7 ± 0.5 in the ED and normal group, respectively. If combined, a mean value of 3% would reasonably become evident. This result, to still be significantly lower, would require normals to show an even higher dilation response, about 4% to 4.5%. This figure seems to be a rather unusual response after wrist occlusion (4).
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References
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- Kaiser DR, Billups K, Mason C, Wetterling R, Lundberg JL, Bank AJ. Impaired brachial artery endothelium-dependent and -independent vasodilation in men with erectile dysfunction and no other clinical cardiovascular disease J Am Coll Cardiol 2004;43:179-184.[Abstract/Free Full Text]
- Rosen RC, Riley A, Wagner G, Osterloh IH, Kirkpatrick J, Mishra A. The International Index of Erectile Function (IIEF): a multidimensional scale for assessment of erectile dysfunction Urology 1997;49:822-830.[CrossRef][Medline]
- Cappelleri JC, Rosen RC, Smith MD, Mishra A, Osterloh IH. Diagnostic evaluation of the erectile function domain of the International Index of Erectile Function Urology 1999;54:346-351.[CrossRef][Medline]
- Betik AC, Luckham VB, Hughson RL. Flow-mediated dilation in human brachial artery after different circulatory occlusion conditions Am J Physiol Circ Physiol 2004;286:H442-8.
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