Testosterone Therapy on Angina Threshold and Atheroma in Patients With Chronic Stable Angina

In the past 4 years the investigators' research group has completed 2 studies on the effect of testosterone therapy on exercise induced coronary ischaemia (clinically manifest as angina pectoris). We, the investigators at Sheffield Teaching Hospitals, have shown that testosterone replacement therapy improved exercise duration on the treadmill and prolonged time to ischaemia (ischaemic threshold). Moreover, we demonstrated a dose response relationship between the increase in exercise duration and the baseline testosterone level so that men with lower baseline testosterone level derived the greatest symptomatic benefit from replacement therapy. Importantly we have also demonstrated that the effects of testosterone are maintained in the presence of concomitant anti-anginal drug therapy and at physiological levels of testosterone therapy. (English et al. 2000; Malkin 2004)

Furthermore we have found the prevalence of men with coronary disease and low serum testosterone levels to be approximately 25%. This represents a large population of men with low testosterone levels that may benefit symptomatically from testosterone therapy. These men qualify for androgen replacement therapy per se simply to relieve hypogonadal symptoms and maintain bone mineral density and there are clinical guidelines recommending physiological testosterone replacement in this cohort. (Morales and Lunenfeld 2002) The safety issues relating to testosterone treatment which comprise a theoretical increased risk of prostate neoplasia and increased erythropoiesis are of limited relevance in this population because replacement therapy only returns the testosterone level to the physiological range. Indeed, there is no evidence that appropriate testosterone therapy increases the risk of prostate cancer. More importantly, prostate cancer can be identified early by screening for prostate specific antigen allowing careful surveillance during replacement therapy.

This study aims to address the following questions on the effects of testosterone therapy in men with coronary ischaemia:

• Does the anti-anginal effect persist long term? Many of the published studies are acute single dose trials and none of the chronic studies have assessed patients formally beyond a few months. Our earlier studies were limited to 3 months.
• Does testosterone therapy in men affect the levels of measurable atheroma? There is currently no in-vivo human evidence that androgen therapy inhibits or reduces levels of atheroma, although there is abundant evidence in animals to suggest a potential improvement.

This study addresses the two issues and would be of one-year duration but would be the longest trial of testosterone therapy in men with cardiovascular disease.

The primary endpoint is change in time to ST- segment depression of > 1mm during exercise testing.