Myocardial ischaemia is caused by the reduction of coronary blood flow as a result of fixed or dynamic epicardial coronary artery stenosis, abnormal constriction or deficient relaxation of coronary microcirculation, or because of reduced oxygen-carrying capacity of the blood.56 Atherosclerosis is the major cause of myocardial ischaemia. Plaque that develops in atherosclerosis can rupture causing platelet aggregation and subsequent thrombus formation, which leads to MI. The other mechanisms of myocardial ischaemia are encountered far less than atherosclerosis. Endothelial dysfunction has an important role in the progression of atherosclerosis. Endothelial dysfunction enhances the intimal proliferation and malregulation that results in plaque destabilisation in the arteries.6 This process, coupled with paradoxical vasoconstriction, can result in major cardiovascular events such as MI.32
A considerable number of patients with ED can have psychogenic factors as the only cause, or in combination with organic causes of ED. Depression, low self-esteem and social stresses are among the psychogenic factors that can lead to ED. Depression is an independent risk factor for both ED and IHD; these three disease conditions are interlinked.51 Psychogenic ED can be managed by multiple psychological interventions such as cognitive behavioural therapy, couples counselling and guided sexual stimulation techniques.52
Crossref | PubMed | Scopus (56) | Google ScholarSee all References When matched for age, hypertension, diabetes, and tobacco use, no significant difference was noted in the presence of ED (42% in the myocardial infarction group vs 48% in the control group). However, the presence of severe congestive heart failure has been associated with increased ED. A study of 80 patients with New York Heart Association class III/IV congestive heart failure found that 40% of these patients had complete ED, and another 40% had either mild or moderate ED.15x15Taylor, HA Jr. Sexual activity and the cardiovascular patient: guidelines. Am J Cardiol. 1999; 84: 6N–10N

Another common reason for failures of oral therapy is the absence of sexual or genital stimulation prior to attempting sexual intercourse. These medicines facilitate an erection by increasing blood flow to the penis, but they do not act as an aphrodisiac or as an initiator of the erection. A man who is not “in the mood” or does not have adequate physical stimulation will not respond with an erection.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Rates of severe cardiovascular adverse effects were also similar at 1.7 per 1000 person-years of treatment with sildenafil compared with 1.0 events per 1000 personyears with placebo treatment.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
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

When these drugs don't work, there are other options. Medications that dilate blood vessels, such as alprostadil, can be injected or deposited in the penis; they work in more than 80 percent of men with diabetes. Beyond that, penile implants can be an effective surgical solution. Implants are either malleable rods, which can be manually adjusted to the desired position, or inflatable cylinders that fill with fluid when a pump under the skin of the scrotum is pressed.
Erections also require neural input to redirect blood flow into the corpora cavernosae. Psychogenic erections secondary to sexual images or auditory stimuli relay sensual input to the spinal cord at T-11 to L-2. Neural impulses flow to the pelvic vascular bed, redirecting blood flow into the corpora cavernosae. Reflex erections secondary to tactile stimulus to the penis or genital area activate a reflex arc with sacral roots at S2 to S4. Nocturnal erections occur during rapid-eye-movement (REM) sleep and occur 3–4 times nightly. Depressed men rarely experience REM sleep and therefore do not have nocturnal or early-morning erections.
SOURCES: American Urological Association, "AUA Guideline on the Management of Erectile Dysfunction: Diagnosis and Treatment Recommendations." Barksdale, J. Pharmacotherapy, May 1999; vol 19: pp 573-581. Ferrario, C. Journal of Clinical Hypertension, November/December 2002; vol 4: pp 424-432. Fogari, R. American Journal of Hypertension, January 2001; vol. 14: pp 27-31. Grimm, R. Hypertension, January 1997; vol 29: pp 8-14. Llisteri, J. American Journal of the Medical Sciences, May 2001; vol. 321: pp 336-341. WebMD Medical Reference provided in collaboration with The Cleveland Clinic: "Hypertension: Treatment With ACE Inhibitors."
To date, there are no studies directly comparing the effectiveness of these three agents among diabetic men with ED, so it is impossible to state that one agent is superior to another in terms of effectiveness in diabetic patients. However, there are an number of studies that compare the individual agents to placebo in diabetic men with ED. For example, Boulton et al.41 completed a 12-week double-blind, placebo-controlled randomized clinical trial of the effectiveness of sildenafil in 219 men with ED and type 2 diabetes. They found that sildenafil resulted in a significant improvement in the ability to both achieve and maintain an erection adequate for sexual intercourse in men with type 2 diabetes. In a similar study, Rendell et al.42 randomized 268 diabetic men with ED to receive either sildenafil in a dose-escalation manner or placebo. At the conclusion of the 12-week study, 56% of the patients in the sildenafil arm reported improved erections, compared to 10% in the placebo arm (P < 0.001). Additionally, 61% of patients in the diabetic arm reported at least one successful attempt at sexual intercourse in the final month of the study, compared to 22% in the control arm (P < 0.001). Similar randomized studies have documented the effectiveness of both tadalafil43 and vardenafil44 in the treatment of diabetes-related ED.
As a primary care doctor, my most important job is to tailor treatment for my patients while still making decisions based on the medical literature. So when patients tell me their treatment is causing undesired side effects—like ED—I work with them to create a plan to treat the condition while also finding a way to relieve those side effects. Fortunately, there are ways to deal with medically induced ED.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Sildenafil has a 4000-fold increased selectivity for PDE-5 over PDE-3, has negligible effects on heart rate, and has only a modest effect on blood pressure level in healthy persons, with an average systolic pressure decrease of 10 mm Hg with a single dose of 100 mg.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
A deficiency of L-arginine, however, does not generally disrupt nitric oxide synthesis because L-arginine availability is not the rate-limiting step in this process. In fact, research over the past five years has identified an endogenous (occurs in the body naturally) inhibitor called “asymmetric dimethylarginine” or ADMA, an amino acid which blocks the production of nitric oxide. By acting as an L-arginine mimic, this damaging look-alike effectively elbows out L-arginine and pushes it off to the side in the biochemical pathway leading to the synthesis of nitric oxide. ADMA is relatively elevated in patients with hypertension, high levels of cholesterol, triglycerides, homocysteine and low-density lipoprotein (LDL), and low levels of high-density lipoprotein (HDL), as well as with aging itself. This inhibitor of nitric oxide synthesis may very well be the common factor shared by all of these abnormal conditions. Increased levels of this detrimental inhibitor (ADMA) block nitric oxide production, leading to endothelial dysfunction.

How common is impotence? According to findings from several studies, including “The Massachusetts Male Aging Study,” overall prevalence for men between 40–70 years old is around 52 percent (or around 30 percent of all men between 18–60 years old). That’s right — nearly half of all men over 40 experience erectile dysfunction symptoms at some point. Not surprisingly, research demonstrates that impotence is increasingly prevalent with age. Around 40 percent of men in their 40s experience sexual dysfunction. Up to 70 percent of men in their 70s experience ED. (1) Every year more than 617,000 new cases of impotence occur in the United States alone.
Erections also require neural input to redirect blood flow into the corpora cavernosae. Psychogenic erections secondary to sexual images or auditory stimuli relay sensual input to the spinal cord at T-11 to L-2. Neural impulses flow to the pelvic vascular bed, redirecting blood flow into the corpora cavernosae. Reflex erections secondary to tactile stimulus to the penis or genital area activate a reflex arc with sacral roots at S2 to S4. Nocturnal erections occur during rapid-eye-movement (REM) sleep and occur 3–4 times nightly. Depressed men rarely experience REM sleep and therefore do not have nocturnal or early-morning erections.
Older age. A man’s risk increases past the age of 40, as age is the variable most strongly associated with impotence. This is due to changing hormones, higher risk for heart problems and those affecting circulation, and decreased sexual desire that often occurs with increasing age. For example, based on findings from the National Health and Social Life Survey, it’s been found that “men between 50–60 years old are more than 3 times as likely to experience erection problems and to report low sexual desire compared to men aged 18 to 29 years.” (3)
But closer questioning often revealed a very different story—men would admit that struggles to achieve an erection usually preceded a heart attack or other cardiac event by one, two, or three years. Back then, the pattern of erectile dysfunction and cardiac disease was so widespread, that most in the medical profession attributed it to simple “aging,” as common as wrinkles and constipation.

Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Sildenafil is absorbed rapidly, and peak plasma levels of 127 to 560 ng/mL are seen in a fasting state approximately 1 hour (range, 0.5-2 hours) after ingestion.3x3Zusman, RM, Morales, A, Glasser, DB, and Osterloh, IH. Overall cardiovascular profile of sildenafil citrate. Am J Cardiol. 1999; 83: 35C–44C
Diabetes doubles or even triples the chance that you’ll have erectile dysfunction (ED) and that you could develop it a decade earlier than other men. In fact, the two conditions are so closely linked that some experts believe that for men younger than 45, impotence, or ED, could be an early warning sign of diabetes. The good news is that diabetes treatment, especially if you identify type 2 diabetes early, can also ease ED.
If you’re taking medication to treat blood pressure, depression, pain, allergies, inflammation, seizures, or heart conditions, you’re one of the tens of millions of people at risk for medically induced erectile dysfunction. It’s just the nature of drug side effects. Yet erectile dysfunction is one of the least talked about side effects of prescription medication.
Crossref | PubMed | Scopus (539) | Google ScholarSee all References The MMAS 9-year follow-up study has shown that a body mass index of 28 kg/m2 or higher was an independent predictor for ED, with an adjusted odds ratio of 1.96.5x5Feldman, 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
Chlamydia and erectile dysfunction: What's the link? Some people who have chlamydia also experience erectile dysfunction (ED), which involves problems getting or maintaining an erection. Chlamydia can infect the prostate gland, leading to prostatitis, pain, and ED. In this article, learn more about the link between this common infection and ED, and treatments for both. Read now
Abstract | Full Text | Full Text PDF | PubMed | Scopus (395) | Google ScholarSee all References Sildenafil has no effect on bleeding time or prothrombin time when used either alone or in patients taking aspirin or warfarin.61x61Nehra, A, Colreavy, F, Khandheria, BK, and Chandrasekaran, K. Sildenafil citrate, a selective phosphodiesterase type 5 inhibitor: urologic and cardiovascular implications. World J Urol. 2001; 19: 40–45
Yohimbe. Before Viagra and the other prescription erectile dysfunction drugs became available, doctors sometimes prescribed a derivative of the herb yohimbe (yohimbine hydrochloride) to their patients suffering from ED. But experts say the medication is not particularly effective, and it can cause jitteriness and other problems. "It's not a great drug," says McCullough. "And I suspect the herb is not as potent as the pharmaceutical version." What's more, evidence shows that yohimbe is associated with high blood pressure, anxiety, headache, and other health problems. Experts discourage its use.
The aetiology of predominantly psychogenic ED is multifactorial, and components may include psychiatric disorders (especially depression), interpersonal problems with the sexual partner or misconceptions about normal sexual activity. Identifying and getting treatment for those patients with psychogenic causes of ED such as depression that may also increase CVD risk is also important.
A follow-up study from the ExCEED database compared men with ED and prostate cancer to men with ED without prostate cancer and found that the prostate cancer survivors had worse erectile function but reported better quality of life than those without prostate cancer.37 The authors hypothesized that the prostate cancer survivors were able to “rationalize” away their sexual dysfunction with the knowledge that they may have been “cured” of their prostate cancer. Clearly, diabetic men could not use the same rationale.
The Epimedium plant is a flowering perennial found throughout Asia and parts of the Mediterranean. Horny Goat Weed’s active ingredient is icariin, a falvonol glycoside and reputed to improve cardiovascular function, hormone regulation, modulation of immunological function and antitumor activity (44). Icariin has also been shown to have a PDE5i effect. Animal studies have been carried out showing improvements in penile hemodynamic parameters. There is one report of tachyarrhythmia and hypomania with the use of this herb (45).

Relation between erectile dysfunction prevalence and type of coronary syndrome (A). Time interval (months) between erectile dysfunction and coronary artery disease symptom onset in chronic coronary syndrome according to the number of vessels involved (B). ACS, acute coronary syndrome; CCS, chronic coronary syndrome, G1: ACS and 1-VD; G2: ACS and 2-,3-VD; G3: CCS. VD, vessel disease; C: the control group with normal coronary angiography. With permission from Montorsi et al.15
Despite its limitations in detecting CVD without significant stenosis, EST (with or without imaging) can further define the cardiovascular risk in patients with ED and no overt CAD and may be particularly helpful for identifying silent CAD in patients with diabetes. Chemical stress tests are appropriate for patients who cannot complete an EST or in whom ECG is non-interpretable. In patients with established CVD, an interpretable EST is mandatory in the indeterminate risk category and is at the discretion of the cardiologist in the low risk category (Table 3B), since it determines exercise ability and estimates cardiovascular risk associated with sexual activity.
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