COMMENTARIES

Asymmetric Development of Peripheral Atherosclerosis in Patients with Erectile Dysfunction: an Ultrasonographic Study

C. Foresta and N. Caretta, Section of Clinical Pathology, Center for Male Gamete, Cryopreservation, Department of Histology, Microbiology and Medical Biotecnology; University of Padova, via Modena 9, 35128 Padova, Italy, Tel: (+39) 0498517, Fax: (+39) 498218520, Email: carlo.foresta@unipd.it

C. Foresta

Introduction

Erectile dysfunction (ED), defined as the consistent inability to obtain and maintain an erection for satisfactory sexual intercourse, has a strong impact in the adult male population, affecting approximately 20 million men in the U.S.A. [1] and about 3 million men in Italy [2]. The pathophysiology of ED is multifactorial, but it mainly involves a vascular disorder related to a reduction of the endothelial function [3]. Increasing evidence suggests the importance of ED as a reliable predictive parameter of cardio-vascular diseases [4]. The co-morbidity of ED with vascular disorders as coronary artery disease [5] and carotid wall damage [6] have been exhaustively addressed, but data on the arterial wall of lower-limbs in patients with ED are still lacking. The increase of intima-media thickness (IMT) is the earliest morphological alteration of arterial wall detectable with ultrasonography (US) and, together with the presence of non-stenotic plaques, it has been related to the presence of vascular ED [6], cardiovascular risk factors (CVRFs) [7], previous cardiovascular events [8], as well as effects of lowering lipid therapies [9]. The large majority of vascular studies in ED patients focused on carotid atherosclerotic lesions, whereas few of them considered also femoral wall alterations. This is likely due to a higher reproducibility of measurements at carotid level, given its favorable superficial site and straight course. Actually, studies evaluating the utility of femoral US study in ED patients are lacking. Nevertheless, femoral arteries are anatomically closer to cavernous arteries (same origin from common iliac artery) with respect to the carotid district. Femoral atherosclerotic wall alterations, therefore, may be linked to an impairment of cavernous peak systolic velocity (PSV), as measured by penile colour doppler ultrasonography (P-CDU), usually observed in ED of vascular origin.

 

Asymmetric Development of Peripheral Atherosclerosis

A large body of evidence recently suggested an asymmetric development of peripheral atherosclerosis. In the general population femoral atherosclerosis seems to be more frequent than carotid atherosclerosis independently from CVRFs [10], and in some defined categories of patients, a preferential site of plaque occurrence in the femoral district was found. In particular, Danese et al. [11] found a significantly higher prevalence of femoral versus carotid plaques in patients affected by type 2 diabetes mellitus and a non-significant trend of carotid with respect to femoral plaques in hypertension. Moreover, Vaudo et al. [12] showed a significant increase of atherosclerotic lesions at femoral site in patients affected by metabolic syndrome. Furthermore, there are studies addressing femoral atherosclerotic lesions as early predictors of coronary atherosclerosis. For example, Lekakis et al. [13] found a positive correlation between femoral district IMT and the extent and severity of coronary artery disease, better than at common carotid and carotid bulb sites. Lisowska et al. [14] found that the presence of plaques at femoral site, more faithfully than at carotid site, strongly correlated with the three vessels coronary disease. In the same study, the significantly different frequency of wall alterations between carotid and femoral site was theoretically explained with an anatomical hypothesis: the course of common femoral artery, which is less straight than at common carotid site, facilitates nonlinear flow that in turn leads to thickening of artery walls and, later, to plaque formation.

 

Prevalence of Carotid and Femoral Atherosclerotic Lesions in ED Patients

Possible relationships between different districts involved in the atherosclerotic process and ED have not been previously investigated, and data on the common femoral artery in ED are lacking. Our results are consistent with a link between femoral atherosclerosis and ED. In fact a heterogeneous sample of 238 ED patients presented with a significantly higher prevalence of femoral plaques with respect to the control group, independently from the presence of CVRFs. Moreover, in ED patients the femoral district was absolutely more frequently damaged with respect to the carotid district. We found no difference in the prevalence of increased IMT between ED and controls: this result seems to be in contrast with previous studies [15] showing a higher prevalence of increased IMT in ED patients. However, in these studies plaque occurrence was not analyzed, whereas we separately evaluated carotid and femoral plaques and classified all subjects on the basis of the advancement of atherosclerotic lesions. In this way, and in order to evaluate the prevalence of early atherosclerotic lesions, we considered subjects with increased IMT, at carotid or femoral site, only after excluding the presence of plaques. Therefore, in order to better analyze early atherosclerosis in patients without plaques, we focused on IMT at carotid and femoral site, observing that only in ED patients was femoral IMT significantly higher than carotid IMT. This result further suggests that in ED patients atherosclerosis develops asymmetrically. Penile mean PSV was significantly lower when atherosclerotic lesions were present, irrespectively of the district involved. Only one study [16] correlated penile PSV and peripheral atherosclerotic lesions, showing significantly lower mean penile PSV values in ED patients with alterations at carotid, femoral, or both sites with respect to ED patients without peripheral atherosclerotic lesions. Our data confirm these findings in a larger group of patients and also reveal a negative correlation with the IMT and the severity of vessel stenosis at both carotid and femoral site. Moreover, we showed a site-dependent difference: penile PSV was significantly lower if plaques occurred at isolated carotid or at combined carotid and femoral sites with respect to isolated femoral site. The lower penile PSV in patients with isolated carotid atherosclerosis could be explained with a significant difference in patients’ age: subjects with carotid plaques are significantly older than subjects with femoral plaques. This difference also suggests that atherosclerotic plaques seem to arise earlier at femoral than at carotid site, even if further studies with a larger number of patients are required to confirm our hypothesis.

 

Conclusion

We showed for the first time that the prevalence of femoral artery atherosclerosis (both isolated and simultaneously associated with carotid artery plaques) is significantly higher in ED patients with respect to controls, irrespectively of other CVRFs. Furthermore, in ED patients the femoral district is the more frequently damaged arterial site, showing a possible early development of atherosclerosis.

          Taken together, our data confirm the strong relation between atherosclerosis and ED and suggest an asymmetric development of atherosclerotic lesions in ED patients. Therefore, in order to check atherosclerosis development in ED patients, irrespective of CVRFs, we suggest performing both carotid and femoral ultrasonographic examination [17].

References

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  17.    Foresta C, Palego P, Schipilliti M, Selice R, Ferlin A, Caretta N. 2008. Asymmetric development of peripheral atherosclerosis in patients with erectile dysfunction: an ultrasonographic study. Atherosclerosis 197(2): 889-95. Epub 2007 Sep 14.

 

 

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