Penile erection is largely a vascular process, and the penile endothelium and smooth muscle tissue are very sensitive to functional and structural changes. Vasculogenic ED results from an impairment of endothelial dependent or independent smooth muscle relaxation (functional vascular ED, initial stages), occlusion of the cavernosal arteries by atherosclerosis (structural vascular ED, late stages), or a combination of these.3 Current data support a complex interplay between endothelial dysfunction, subclinical inflammation, and androgen deficiency (Figure 1). The relationship between ED and CAD at the clinical level is supported by this common pathophysiological basis. The ‘artery size’ hypothesis explains why patients with CAD frequently report ED before CAD detection.10 According to this hypothesis, for a given atherosclerotic burden, the smaller penile arteries suffer obstruction earlier than the larger coronary arteries (Figure 2). The same concept holds also true in the case of non-obstructing atherosclerosis: since the smaller penile artery have a greater endothelial surface and erection requires a large degree of vasodilation to occur when compared with arteries in other organs, the same degree of endothelial dysfunction will be symptomatic in these smaller vessels but subclinical in the larger ones (i.e. coronaries). In the same context, accelerated arterial ageing (as indicated by increased arterial stiffening that also affects large arteries of ED patients) may be a common background.11,12 Erectile dysfunction is associated with an incremental inflammatory and endothelial-pro-thrombotic activation.13 Interestingly, this activation is equal to that found in CAD patients with no ED, while when these two conditions are combined the burden is additive. Androgen deficiency may be also implicated in the common pathogenetic pathways of ED and CVD; however, this warrants further substantiation.2
Unfortunately, government agencies often are slow to respond to new scientific information and economic and political forces make it difficult for our population to receive clear information informing them that heart disease is nutritionally induced and totally avoidable with dietary excellence. Sadly, even the American Heart Association advocates a diet that has been shown to actually increase heart disease.
PubMed | Google ScholarSee all References This prolonged excretion half-life produces enhanced erections up to 36 hours after oral dosing, thereby potentially allowing for more spontaneous engagement of intercourse. The efficacy of tadalafil in the treatment of ED has been proved in randomized double-blind, placebo-controlled trials.78x78Porst, H, Padma-Nathan, H, Giuliano, F, Anglin, G, Varanese, L, and Rosen, R. Efficacy of tadalafil for the treatment of erectile dysfunction at 24 and 36 hours after dosing: a randomized controlled trial. Urology. 2003; 62: 121–125
When dealing with certain medical conditions, it is important to focus treatment toward the root of the problem. If you were to properly manage your high blood pressure without the use of any confounding medications and instead employ a lifestyle change, both ailments would likely disappear. While this would be the ideal case, it isn’t the reality for most patients. Medications are great for controlling high blood pressure, but it’s important to speak with your doctor about any concerns before taking them.
The development of PDE5-inhibitors is a clear example of how Western medicine approached the problem of ED differently from Eastern medicine. The erectogenic effect of sildenafil (Viagra®) was discovered by accident when patients undergoing heart clinical trials reported better erections as a side effect after taking sildenafil. This observation led to further elucidation of the NO/cGMP signalling pathway and development of PDE5-inhibitors as a first-line therapy in ED (5).
Erectile dysfunction carries an independent risk for cardiovascular events. A considerable number of studies have examined the ability of ED to predict the risk of future fatal and non-fatal cardiovascular events (myocardial infarction, stroke, revascularization) and total mortality in the general population and in high CV risk patients, in diabetics and in heart failure patients.5,19–22 In a meta-analysis of 14 prospective cohort studies involving 92 757 men followed for a mean period of 6.1 years (Figure 4), ED increased significantly and independently of traditional risk factors the risk of CV events, CV mortality, myocardial infarction, cerebrovascular events, and all-cause mortality by 44, 19, 62, 39, and 25% respectively.5 This predictive ability also extends in men with known CVD: ED increased the risk of all-cause mortality by 90%.5 Of importance, the predictive ability of ED is higher in younger ED patients5 despite the fact that probability of ED increases with age, most likely identifying a group of patients with early and aggressive vascular disease.23 Clinical implementation of ED as a biomarker relies on whether its addition on classical risk scores such as the Systematic COronary Risk Evaluation (SCORE) or the Framingham correctly reclassifies a meaningful percentage of patients into a higher or lower risk category. To this end, data are limited. Yet, in a population-based study of men 40–70 years of age, the addition of the ED status to the Framingham risk score resulted in a reclassification of 6.4% of low-risk patients to intermediate risk.19
Abstract | Full Text PDF | PubMed | Scopus (3562) | Google ScholarSee all References By 1996, fueled by the availability of the new oral agent sildenafil, the number of outpatient visits for ED as estimated by the National Ambulatory Medical Care Survey had increased to 1.3 million per year.5x5Feldman, HA, Johannes, CB, Derby, CA et al. Erectile dysfunction and coronary risk factors: prospective results from the Massachusetts Male Aging Study. Prev Med. 2000; 30: 328–338
Abstract | Full Text PDF | PubMed | Scopus (29) | Google ScholarSee all References After controlling for diabetes mellitus, tobacco use, and hyperlipidemia, hypertension was not found to be an independent predictor of vasculogenic ED in 440 impotent men as measured by the PBI.7x7Virag, R, Bouilly, P, and Frydman, D. Is impotence an arterial disorder? a study of arterial risk factors in 440 impotent men. Lancet. 1985; 1: 181–184
If not properly controlled, both type 1 and type 2 diabetes can cause complications due to high blood sugar levels. Over time, these high levels can cause irreversible nerve damage and narrow your blood vessels. While nerve damage may affect the sensitivity of your penis, blood vessel damage can affect the blood flow to your penis and make it more difficult for you to get an erection.
The impact of third-generation cardioselective beta-blockers such as carvedilol and nebivolol has also been investigated. Fogari et al. investigated the effect of carvedilol on erectile function in a double-blind crossover study involving 160 men newly diagnosed with hypertension and found chronic worsening of sexual function in those treated with carvedilol compared with valsartan and placebo.24
If you have symptoms of ED, it’s important to check with your doctor before trying any treatments on your own. This is because ED can be a sign of other health problems. For instance, heart disease or high cholesterol could cause ED symptoms. With a diagnosis, your doctor could recommend a number of steps that would likely improve both your heart health and your ED. These steps include lowering your cholesterol, reducing your weight, or taking medications to unclog your blood vessels.
In another study, 60 patients underwent stress exercise cardiovascular testing and Doppler ultrasonography for measurement of their cavernosal artery peak systolic velocity (PSV).17x17Kawanishi, Y, Lee, KS, Kimura, K et al. Screening of ischemic heart disease with cavernous artery blood flow in erectile dysfunctional patients. Int J Impot Res. 2001; 13: 100–103
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The authors observe that multiple factors may be involved. In addition to decreased exercise capacity, patients with chronic heart failure have blood vessel and circulation abnormalities that can reduce blood flow into the penis and interfere with the ability to maintain an erection. And erectile dysfunction can be caused or worsened by many of the medications that are commonly prescribed to treat chronic heart failure.
Arginine. The amino acid L-arginine, which occurs naturally in food, boosts the body's production of nitric oxide, a compound that facilitates erections by dilating blood vessels in the penis. Studies examining L-arginine's effectiveness against impotence have yielded mixed results. A 1999 trial published in the online journal BJU International found that high doses of L-arginine can help improve sexual function, but only in men with abnormal nitric oxide metabolism, such as that associated with cardiovascular disease. In another study, published in 2003 in the Journal of Sex & Marital Therapy, Bulgarian scientists reported that ED sufferers who took L-arginine along with the pine extract pycnogenol saw major improvements in sexual function with no side effects. Arginine can be helpful, says Geo Espinosa, ND, director of the Integrative Urological Center at NYU Langone Medical Center. Espinosa says that men with known cardiovascular problems should take it only with a doctor's supervision; L-arginine can interact with some medications.
Crossref | PubMed | Scopus (165) | Google ScholarSee all References Typically, the response to sexual activity is no more than an increase in heart rate to 130 beats/min and an increase in systolic blood pressure level to 170 mm Hg.51x51DeBusk, R, Drory, Y, Goldstein, I et al. Management of sexual dysfunction in patients with cardiovascular disease: recommendations of the Princeton Consensus Panel. Am J Cardiol. 2000; 86: 62F–68F
Whereas management of sexual dysfunction in previously untreated hypertensive patients can be a challenging procedure, confronting the same clinical condition in individuals under antihypertensive regime can be even more demanding. In such cases there will always be a question hovering over physicians head. Is hypertension per se, antihypertensive medication or both, the causative factors provoking sexual dysfunction?
Abstract | Full Text | Full Text PDF | PubMed | Scopus (30) | Google ScholarSee all References Erections result from relaxation of the corpora cavernosa, which is mediated either by increasing intracellular cyclic guanosine monophosphate (cGMP) or cyclic adenosine monophosphate or by inhibition of their degradation. Increased parasympathetic tone results in a decrease in norepinephrine release and an increase in the release of acetylcholine; subsequently, NO synthase activity increases, which releases NO from both endothelial cells and nonadrenergic, noncholinergic neurons.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
Three longitudinal studies have estimated incidence rates of ED in men with diabetes. Unfortunately, none of these studies specifically examined men with type 2 disease. In a cohort of 278 diabetic men with type 1 or type 2 diabetes potent at study entry, the proportion of patients reporting ED at 5-year follow-up was 28%.7 A follow-up analysis of the Massachusetts Male Aging Study, a community-based cohort of men between 40 and 70 years of age, found that the incidence of ED in the diabetic men was 51/1,000 population-years.8 This figure was similar to the 68/1,000 person-years crude incidence rate of ED reported in a study of 1,010 men with diabetes.5 However, new studies need to be carried out in well-characterized populations of men with diabetes in order to better determine the incidence of ED and potential effects of interventions to reduce complications.
The discovery in 1992 of the second messenger of cavernosal smooth muscle relaxation was the critical step that led to the era of nonhormonal oral drug therapy for ED. In 1998, the multicenter trial of sildenafil in the treatment of ED was published in the New England Journal of Medicine, and the era of the phosphodiesterase type 5 (PDE-5) inhibitor began.1 For 5 years, sildenafil was the primary therapy for men with EDDM. Recently, 2 new PDE-5 inhibitors, vardenafil and tadalafil, were introduced.
The great majority of ED cases in diabetic men have a physical cause, such as neuropathy or circulatory problems. In some cases, however, the cause of ED is psychological, including depression, guilt, or anxiety. With a thorough exam, the doctor should be able to determine whether the ED is psychological or physical in nature. If the cause is psychological, your doctor may refer you to a psychiatrist, psychologist, sex therapist, or marital counselor. Do not view such a diagnosis as an insult. Most psychologically-based ED is easily and successfully treated.