May 16 2005
Men with high blood pressure have a new reason to get their condition under control – they may be at risk for erectile dysfunction, medical experts announced at the American Society of Hypertension’s Twentieth Annual Scientific Meeting.
Two separate studies presented this week uncovered a commonly hypothesized link between the hypertension and erectile dysfunction (ED). One of these studies also demonstrated that of long-term use of sildenafil, a commonly prescribed ED treatment, was effective in improving aortic stiffness in patients suffering from the condition.
"It is estimated that at least 20 million American men have some degree of erectile dysfunction," said Dr. Michael Doumas, from the 4th Department of Internal Medicine, University of Athens, Greece. "Our research determined that for men with high blood pressure, the chances that they may be at risk for or have the devastating condition dramatically increases."
Dr. Doumas and colleagues studied 634 young and middle-aged men between the ages of 31 and 65 years, excluding those with history of diabetes mellitus, heart disease, renal failure, liver and vascular disease, as these diseases have been associated with ED. Patients were evaluated for hypertension, as well as medical history, and then were asked to complete out a questionnaire that evaluated their ED according to the International Index of Erectile Function (IIEF).
"The IIEF is widely used considered an accurate test for defining sexual dysfunction," said Dr. Doumas. "Using the IIEF’s ‘inform-then-probe’ technique of questioning, we were able to clearly demonstrate a strong link between high blood pressure and ED."
Overall, 35.2 percent of the 358 patients had some degree of ED, and 9.2 percent of these patients had severe ED (p<.0001). By contrast, only 14.1 percent of patients with normal blood pressure had some degree of the condition, and 1.5 percent of these patients had severe ED (p<.0001).
Interestingly, erectile dysfunction was more frequent even in subjects with high normal blood pressure, now included under the term "prehypertension", suggesting that we must pay special attention at this population.
In a separate study presented at the meeting, Dr. Charalambos Vlachopoulos, from the First Department of Cardiology at Athens Medical School, Greece, examined sildenafil’s long-term effect on aortic stiffness.
"Sildenafil is widely-used for treatment of erectile dysfunction, but the condition is so prevalent and closely linked to risk factors for coronary artery disease that we wanted to explore the drug’s potential beyond ED treatment," said Dr. Vlachopoulos. "We found that the drug has a beneficial long-term effect on aortic stiffness, a risk factor for isolated systolic hypertension, heart attack, stroke, and coronary artery disease."
"We have seen in previous studies that patients suffering from ED and those suffering from coronary artery disease both share a common defect, endothelial dysfunction," Dr. Vlachopoulos continued. "Because sildenafil blocks the breakdown of vasodilating substances produced by the endothelium to aid sexual function, we hypothesized that the drug may help reduce aortic stiffness, which is partly dependent on endothelial function."
The endothelium is a thin cellular layer that covers the innermost surface of all blood vessels. Endothelial function involves the cells’ secretion of important substances, such as nitric oxide, that help control vascular tone and the ability of the vessels to dilate.
In a double-blind study, Dr. Vlachopoulos and colleagues randomized 11 men with ED to either sildenafil 100 mg daily or placebo over 2 weeks. At the end of two weeks, the men receiving placebo switched to sildenafil 100 mg daily and those originally on the ED treatment switched to placebo, and the study continued for another two weeks. Pulse wave velocity was measured at baseline, 7 and 14 days, 24 hours after the last dose. The researchers concluded that arterial stiffness decreased for patients on sildenafil.
"Pulse-wave velocity is a non-invasive method to measure aortic stiffness, using the laws of physics to analyze blood flow as the heart beats," said Dr. Vlachopoulos. "To be sure we were evaluating the long-term effect of the drug, we were careful to take measurements well after the acute effects of the sildenafil had worn off."
While the implications of this study are promising, Dr. Vlachopoulos warned this study is only the beginning of more in-depth research needed in the future. "We are on the cusp of discovering new beneficial effects that seem to extend beyond sildenafil’s acute action."