Friday, February 12, 2010

Penile stress test:window to hearts of men

Many people are hesitant to consult for erectile dysfunction(ED) in their mid 50 s.They think it is a part of ageing.But erectile dysfunction in middle ages can be because of generalised endothelial dysfunction.It could be a presursor of future heart problems.That is the reason many andrologist would call erectile dysfunction as a “wake up call” to coronary artery disease.It has been found that after adjustment for age, ED correlated with the presence of heart disease, hypertension, Diabetes Mellitus, smoking and inversely with protective Lipids(HDL).

Penile erection is caused by a series of actions: relaxation of cavernosal arteries and cavernosal sinuses leads to increased blood flow into the penis, pooling of blood in the sinuses, and an increase in corpus cavernosum pressure.The same NO-cGMP pathway that is critical to erectile function was discovered years earlier as a key endothelium derived dilator of arteries in the systemic, coronary, and
pulmonary vasculatures.In the clinical setting, loss of endothelial NO occurs in the earliest stages of atherosclerosis. In fact, it has been linked to each of the known atherogenic risk factors, such as various forms of dyslipidemia, hypertension, diabetes, cigarette smoking, aging, menopause, hyperhomocystinemia, and a family history of premature atherosclerosis.Although atherosclerosis in its early stages tends to be focal, preferentially localizing to sites of abnormal hemodynamic stresses, loss of endothelium-derived NO in the setting of risk factors is much more generalized and affects nearly all arterial beds, including the arterial blood supply to the penis and the endothelium lining cavernosal sinuses.
Because the arteries supplying penis are smaller than the coronary arteries.So the process causing decereased flow in penile arteries is an harbinger of decreased flow in heart and brain vessels in the future.
So, 57% of men undergoing coronary artery bypass grafting and 64% of men with acute myocardial infarction had preceding ED of some duration. Interestingly, subjects with ED have evidence of endothelial dysfunction in systemic arteries, and an impairment in the NO-cGMP pathway is present before any other evidence of atherosclerotic process is detectable by sophisticated testing. It has been suggested that a deficiency of NO manifests early as ED because erection requires a comparatively large, perhaps 80%, dilation of penile arteries, and hence, this system can ill-afford a loss of NO.Thus, ED, just as endothelial dysfunction, appears to be a sensitive forerunner of atherosclerosis and its complications.

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