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The Penis as a Barometer of Endothelial Health
Andrew R McCullough, MD, FACS
Department of Urology, New York University School of Medicine, New
York, One of the aspects of erectile dysfunction which has been clarified by the introduction of phosphodiesterase-5 inhibitor therapy is the close relationship between the health of the cardiovascular endothelium and erectile dysfunction. Clearly, therefore, erectile dysfunction needs to be seen as not only a sexual issue but possibly as an indicator of a life-threatening disease. Masters and Johnson were the first researchers who introduced the idea that ED was mostly psychological in origin and could be cured with psychological therapy and behavior modification. It was only from the 1970s onwards that the association between ED and diabetes, spinal cord injury, pelvic surgery, traumatic injury and so on was recognized. A whole series of tests including psychiatric examination, hormonal profiles, ultrasonography, penile angiography, and cavernosometry were developed in response to the concerns that arose when the field of penile implant surgery developed. Unfortunately these tests did not clarify the origin of ED, but they did make it very clear that there was a strong association between ED and cardiovascular disease. There is an increasingly clear link being demonstrated between erectile dysfunction and the risk factors for atherosclerotic disease. For example, one recent study of men with erectile dysfunction revealed that just under half had hypertension, round about a fifth had diabetes mellitus, almost a fifth were smokers, and almost four fifths had a body mass index greater than 26 kg/m2, while almost exactly two thirds had low-density lipoprotein cholesterol at a level greater than 120 mg/dL. Further epidemiological findings which have demonstrated a clear link between ED and cardiovascular risk have been obtained from the Massachusetts Male Aging Study. The
new therapies for erectile dysfunction of intracavernosal injection and
intraurethral application of MUSE pellets might have been interpreted As we have already seen from the pages of this website, the penis is a very complicated and hydraulic system which response to both sympathetic and parasympathetic nervous system, with the mechanism of erection that involves both arterial pressure and veno-occlusion. You may also recall that the process of erection is dependent on the presence of both neuronal and endothelial nitric oxide, which is present because of the activity of an enzyme known as nitric oxide synthase (NOS). Any disease process which reduces the level of NOS obviously will reduce the potential for erection, and make a man more subject to the vagaries of erectile failure. The significant point here is that reduction in the level of NOS in the endothelial tissue is associated with cardiovascular disease and endothelial dysfunction. And damage to the endothelium is often seen well in advance of the development of clinically apparent to vascular disease. At this point it's well worth emphasizing that in men under 35 most ED is undoubtedly psychological in origin: it's usually a manifestation of performance anxiety. And in fact it's also worth keeping in mind that because of the close association between performance anxiety and erectile dysfunction, even men who have a clearly organic basis for their dysfunction will undoubtedly have a level of performance anxiety that undermines the foundation of whatever erectile function they have left. That is why a treatment approach that focuses on the physical aspect of arousal and reduces the anxiety level of the man concerned can have a major impact on his erectile capacity even when he is dysfunction has an organic cause. Anyway, the point is this: since there is such a close association between endothelial dysfunction and erectile dysfunction, could ED be used as an indicator of heart problems and circulatory system disorder? The answer to this is a very clear "yes". ED manifests itself much earlier than critical arterial stenosis of the coronary arteries, or indeed before diabetic peripheral neuropathy or hypertensive cardiomyopathy. In short, ED is an early warning sign, which may indicate that a man's cardiovascular system is in desperate need of attention and that an aggressive approach to the control of, for example, dyslipidaemia may be required. Furthermore, enquiring about the level of a man's erectile dysfunction provides an easy opportunity to work out how serious his endothelial disease might actually be. One complicating factor in this whole syndrome is that many of the drugs used for antihypertensive therapy can in fact induce erectile dysfunction. It appears that up to 45% of men with hypertension who also have ED blame the drug regime for hypertension as the cause of their ED. If a man has a regular sex life and he has come to the conclusion that his ED is the product of drugs which is taking, he is likely to stop taking the drugs whenever he wishes to have sex. Whatever the reasoning, the outcome is the same: that his compliance with the drug regime is poor. It's certainly true that many drugs do in fact have an association with erectile dysfunction, although often the effect can be reduced by using different drugs, or by amending the drug regime. Once again, the active involvement of the man's doctor is essential to ensure that both the underlying condition of which he is receiving treatment is satisfactorily addressed, and his erectile dysfunction is minimized. Doctors should constantly monitor the conditions for which they are responsible in their patients: this may be hypertension or dyslipidemia, both of which are associated with cardiovascular disease. Obviously in the case of diabetes, a tight glycaemic control regime will lead to fewer retinal and neurological symptoms. One of the most powerful tools in understanding how patients are responding to treatment, or how their symptoms are developing, is the patient history. So, for example, when talking to a diabetic patient, a doctor may well enquire about chest pain, urinary frequency or claudication, but they should also enquire about one of the most obvious symptoms of endothelial disease, which is the presence of erection problems. In one study, only 14% of diabetic patients were actually asked about their sexual history. Obviously a man always knows his sexual health, even if he takes steps to disguise it from others. But in an interview with the doctor, a question about a man's sexual capacity provides an opportunity for both the patient and the doctor to discuss the relationship between ED and cardiovascular disease. This can remove shame and ensure that the man understands the connection between his physiology and the appearance of symptoms of ED. Although we have gained the impression that Viagra and its counterparts are effective medication, therapeutic efficiency of these drugs is actually around 75 to 80%. This means that a significant number of men have erection problems due to relationship issues that are not dealt with by establishing sexual capacity through drug therapy. In other cases, the man's endothelium may be so damaged that PDE-5 inhibitors simply do not have any effect, which again can be useful indicator: if there are no relationship issues and Viagra does not produce an improvement in erectile capacity, then clearly it is a matter of urgency that man should be investigated for serious vascular disease. And despite the fact that only 25% of men seek treatment for their erectile dysfunction, we should remember that it was not so long ago that fewer than 6% of men were receiving treatment for ED. So great strides have been made in the treatment of ED, but its stigma is still strong. There's a lot of shame around the issue, and doctors and patients alike frequently avoid discussing it. It's important that a man's general practitioner is fully educated in the management of ED and that patients are questioned about their ED to ensure that it is not a manifestation of some much more serious underlying issue. |
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