Most common form of erectile dysfunction is cardiovascular disease

Penile erection occurs because blood fills penile muscle when called upon, therefore, causing the needed ''hydraulic'' pressure for the organ to function. 

This volume of blood is brought in by small pipes, called arteries, which are branches of the large central arteries that bring oxygenated blood from the heart. These are part of the large arterial tree, which is reputed to be so extensive that connected end to end, from the largest to the smallest arteries, can reach the surface of the moon from the earth. 

The arterial system is extensive because each and every cell in the body has to be close to the capillary system to receive adequate oxygenation and nutrition and remove undesired products through the venous system.

The causes

The most common form of erectile dysfunction in men over 40 years of age is inadequate delivery of blood through those arteries into the penis. There are other causes of erectile dysfunction in men, such as psychogenic causes, injury to nerves supplying the organ, and also some medications used to treat some diseases such as high blood pressure, among others. 

These other causes are less common in men over 40, compared to erectile dysfunctions (ED) caused by damaged arteries. This form of ED is also described medically as ''vasculogenic''. This word comes from the Latin word ''vascular'', hence placing this form of ED properly as a cardiovascular disease (CVD).

In the last 120 years or so, the world has moved from virtually no diseases of the arteries such as heart attacks to a situation today where artery related heart and brain diseases are the leading cause of death in low and middle income countries (LIMC). 

In the high income countries of the North, one in two men and women die from disease of the arteries, mainly heart attacks and strokes. With this increase in arterial diseases comes a corresponding increase in artery related ED, pushing it to be the most common in men over 40 years old.

The damage to the arterial system, leading to heart attacks, stroke and erectile dysfunction, is brought about by a process of damage to the arteries called atherosclerosis, which means deposition of hard and also glue-like material inside the wall of the arteries over time, hence stiffening them and also narrowing them so that adequate blood cannot pass through. 

Risk factors

This is caused by a complex process which is brought about by what we now call risk factors for arterial damage. These risk factors are the same whether we are talking about heart attacks, strokes or erectile dysfunction. 

The main ones are diabetes, high blood pressure, elevated cholesterol, smoking, obesity, excess alcohol use, low physical activity, excess stress and also older age particularly over 40 years. 

These adverse risk factors initially interfere with the key inner lining of the arteries called the endothelium. The endothelium is the one that makes the arteries expand or narrow depending on whether the organ they supply needs more or less blood. 

When these factors cause endothelial dysfunction, then blood flow to the organ starts to diminish, therefore reducing function gradually. 

This loss in endothelial function leads to deposition of fats, minerals and other materials in the inner lining of the artery, leading to what are called plaques which block the arteries with devastating consequences.

The arteries of the penis are very small compared to the coronary arteries of the heart. They measure between 0.5mm and 1mm, compared to coronary arteries measuring in average around 3mm. 

This means that when damage occurs in the whole arterial tree, its effects will be felt where arteries are smaller first. This means that most men, who get heart attacks, may have noted early ED or established ED 3 to 5 years before they got the heart attack or stroke. 

It is, therefore, a warning sign. Development of new ED should, therefore, lead a man over 40 years to go for a heart check, because when blockages in arteries are diagnosed early, they can be treated and heart attacks and strokes averted. 

The other reason to seek a medical evaluation is so as to establish if the ED is artery related, because there is a good chance that this type of ED can be treated and even in some cases cured. 

The blood flow in the penis is measured and the damaged arteries visualised in a non-invasive and painless test and, if confirmed, a new treatment called Low Intensity Extracorporeal Shock Wave Therapy (LI-ESWT) can be applied. 

Unlike popular medications that have been in use, but with no hope of cure ESWT has a cure rate of 60 pc to 70 pc in the studies available on the technique. The treatment involves directing focused pulses of ultrasound energy into the penile muscles, in a completely non-invasive and painless way. 

The ultrasound energy results in what is called microtrauma which stimulates the penile muscle to develop new small blood vessels which ultimately increase and restore blood flow in the penis. The treatment comprises 12 sessions of treatment each lasting about 20 minutes and spread over a nine-week period.

The first six sessions are done over three weeks, twice a week for three weeks, followed by a three week treatment free brake, followed by a final six sessions over another three weeks. Treatment is done in an outpatient setting. This treatment is currently available in Nairobi.  

For patients whose reduced blood supply to the penis is due to blockages in the larger arteries in the pelvis, the procedure of balloon angioplasty and stenting, that is commonly applied to the coronary arteries of the heart, can be used with great success.

It is crucial that men with artery based ED modify the risk factors that initially damaged their arteries. They need to exercise regularly, reduce weight if overweight, stop smoking, stop excess use of alcohol, reduce stress and identify early such medical conditions as high blood pressure and diabetes and have them adequently controlled.

For men on treatment for high blood pressure, and who develop ED, it is also important to review medications they are using to see if they could be causing ED, particularly where other causes of ED cannot be found.