Urologists need to consider the increased cardiovascular morbidity in men with erectile dysfunction.
Erectile dysfuction (ED), defined as the inability to reach or maintain an erection sufficient for satisfactory sexual performance, is age-related and an extremely prevalent medical condition. It is estimated to affect more than half of all men over the age of 60, and in the United States alone, ED will develop in more than 600,000 men aged 40-69 annually.1
Recent epidemiologic studies have solidified the relationship between ED, endothelial dysfunction, and cardiovascular disease (CVD). Although it is well accepted that these entities have common risk factors such as diabetes, obesity, hypertension, dyslipidemia, smoking, and metabolic syndrome, the role of ED as an early indicator of future cardiovascular morbidity is emerging. The urologic community stands at the forefront in promoting to medical colleagues the concept that ED is the “canary in the coal mine” for cardiovascular health.
Vital message for patients
Moreover, it is vital that we convey this message to ED patients. If they understand the link between ED and endothelial dysfunction and CAD, patients may be more willing to seek medical attention for ED, initiate proactive strategies to improve overall cardiovascular health, and ad-here to chronic phosphodiesterase-5 (PDE-5) therapy if its beneficial effects on endothelial dysfunction and CAD is further established.
There are two mechanisms by which CVD and ED are interrelated. In one model, the uniform vascular obstruction occurring secondary to atherosclerosis has a demonstrable clinical effect on the smaller penile arteries prior to the larger-diameter coronary arteries. In the second model, diffuse endothelial dysfunction defined as impaired nitric oxide (NO)-mediated smooth muscle relaxation occurs throughout the body and one of its early clinical manifestations is ED.
Pritzker et al2 were the first to demonstrate that a substantial number of “healthy” men with ED when further examined were discovered to have silent CAD. Fifty-six percent of his study population of 50 men with ED and no prior diagnosis of CAD had a positive cardiac stress test. In a pooled analysis of similar subsequent publications 22% of men with ED and no prior CVD had a positive stress test; of greater concern is the fact that 94% of these men had significant coronary stenosis at angiography.
Substantive epidemiologic data recently have further established ED as an independent and significant risk factor for future cardiac events such as MI and stroke. In men with symptomatic CAD and ED, Montorsi et al3 observed that the symptoms of ED were present on average three years prior to MI.
Furthermore, long-standing ED (more than 30 months) was more significantly associated with multiple vessel disease at the time of the initial MI. In a large retrospective analysis of 25,000 men, Blumentals et al4 demonstrated that after adjusting for confounding variables (age at ED diagnosis, smoking, obesity, and medication usage), men with ED had twice the risk of a heart attack as those without ED. On further analysis, men older than 40 years with ED had a three to four times greater risk of a heart attack compared with a younger cohort of men (age 30-39) without ED.
Gazzaruso et al5 recently defined the relationship between ED, silent significant myocardial ischemia, and type 2 diabetes. ED was present in 33.8% of diabetics with silent significant CAD compared to only 4.7% in men with no significant CAD. After adjusting for confounding variables, ED was found to be the most accurate predictor of silent CAD in this population.
In a study published in the Journal of the American Medical Association (2005;294:2996-3002), Ian M. Thompson, MD, and his colleagues illuminated the fact that ED is an independent and significant risk factor for future cardiovascular events. The researchers analyzed data on 4,247 men who participated in the Prostate Cancer Prevention Trial, which compared finasteride and placebo. The men were older than 55 years with no ED at study entry.
After five years, 2,420 men (57%) reported ED. After adjusting for all covariates, men with incident ED had a significantly increased risk of angina, MI, and stroke compared to those without ED. The study also highlighted that the longer the duration of ED, the higher the likelihood that these men will experience a cardiovascular event. In their conclusion, ED was cited as an independent risk factor for subsequent cardiovascular events at the same or greater magnitude than a family history of premature CAD, smoking, or hypercholesterolemia.