The initial step in evaluating ED is a thorough sexual history and physical exam. The history can help in distinguishing between the primary and psychogenic causes. It is important to explore the onset, progression, and duration of the problem. If a man gives a history of “no sexual problems until one night,” the problem is most likely related to performance anxiety, disaffection, or an emotional problem. Aside from these causes, only radical prostatectomy or other overt genital tract trauma causes a sudden loss of male sexual function.
Crossref | PubMed | Google ScholarSee all References The risk of myocardial infarction with sexual activity has been estimated to be less than 3% in high-risk patients with prior cardiovascular disease if they can exercise to more than 7 METs without symptoms.89x89Moss, AJ and Benhorin, J. Prognosis and management after a first myocardial infarction. N Engl J Med. 1990; 322: 743–753
Erectile dysfunction (ED) is a common disorder that affects the quality of life of many patients. It is prevalent in more than half of males aged over 60 years. Increasing evidence suggests that ED is predominantly a vascular disorder. Endothelial dysfunction seems to be the common pathological process causing ED. Many common risk factors for atherosclerosis such as diabetes, hypertension, smoking, obesity and hyperlipidaemia are prevalent in patients with ED and so management of these common cardiovascular risk factors can potentially prevent ED. Phosphodiesterase type 5 inhibitors provide short-term change of haemodynamic factors to help initiate and maintain penile erection. They have been shown to be an effective and safe treatment strategy for ED in patients with heart disease, including those with ischaemic heart disease and hypertension.
Ginseng. Korean red ginseng has long been used to stimulate male sexual function, but few studies have tried systematically to confirm its benefits. In one 2002 study involving 45 men with significant ED, the herb helped alleviate symptoms of erectile dysfunction and brought "enhanced penile tip rigidity." Experts aren't sure how ginseng might work, though it's thought to promote nitric oxide synthesis. "I would recommend ginseng [for men with ED]," says Espinosa. Discuss with your doctor before taking it since ginseng can interact with drugs you may already be taking and cause allergic reactions.
Crossref | PubMed | Scopus (539) | Google ScholarSee all References The MMAS found the total prevalence of minimal to severe ED to be 52% and estimated that more than 617,000 new cases were expected to occur annually in the United States.4x4Feldman, HA, Goldstein, I, Hatzichristou, DG, Krane, RJ, and McKinlay, JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994; 151: 54–61
Intraurethral alprostadil (Muse) provides a less invasive alternative to intrapenile injection. It is a pellet that is inserted 5–10 min before intercourse, and its effects last for 1 h. The response rate is ∼50–60%. It can be used twice daily but is not recommended for use with pregnant partners. Complications of priapism and penile fibrosis are less common than after alprostadil given by penile injection. The cost is ∼$18–24 per treatment.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Nitrates have only modest antianginal effects and offer no prognostic benefit for mild recurrent angina or unstable angina. Therefore, such anginal symptoms occurring after sildenafil use should be treated with other nonnitrate antianginal agents such as β-blockers.15x15Taylor, HA Jr. Sexual activity and the cardiovascular patient: guidelines. Am J Cardiol. 1999; 84: 6N–10N
According to the Cleveland Clinic, “because erectile dysfunction is caused by a complex set of psychosocial, neurologic, and vascular factors, a specific cause in a patient may remain ambiguous.” The root causes are often related to a blockage or dysfunction of blood vessels. For example, ED can be due to conditions like atherosclerosis or diabetes, hormonal imbalances or problems related to mental health. It’s been found that common causes typically include one or more of the following factors: (2)
Feeling fatigued, very stressed, depressed or dealing with another mood-related issue that can lower libido. Sources of stress and diminished quality of life — such as “deteriorating economic position,” unhappiness with one’s job or other aspects that lower emotional health — are believed to be major causes for sexual dysfunction in both men and women
The number of men reporting improvement was at 88% during the study. The number of men involved in the study who reported impotence dropped from 75.3 % to 11.8%. The results of this study raise hope for men who have quit taking other blood pressure medications because they interfered with sexual function. Sexual dysfunction was defined for the study as decreased libido, impotence and poor sexual satisfaction.
However, sildenafil should be used carefully with nitrates because their combination can result in severe hypotension and death.68 Both short- and long-acting nitrates are commonly prescribed to treat angina, but they have no prognostic benefit. In addition, there are numerous alternatives to treat angina, such as ranolazine and ivabradine, which do not interact with PDE5 inhibitors. As a result, patients with ED wishing to take PDE5 inhibitors can safely discontinue their nitrates and replace this treatment with the other anti-anginal agents.68

A component of the increased risk conferred by ED could be testosterone deficiency.24 Low testosterone leads to increased levels of total and LDL cholesterol, as well as to increased production of pro-inflammatory markers and mediators.25 Endothelial dysfunction and increased arterial wall thickness, stiffening, and calcification also ensue. On this basis it has been hypothesized that chronically lowered testosterone may increase CVD risk. Indeed, androgen deficiency has emerged as a predictor of CV events, as well as of all-cause and CV mortality, both in the general population and in patients with CV risk factors, with hypertension, with established CVD, and with ED.26 Viewed from the opposite angle, higher serum testosterone showed a protective role for CV events in elderly men.27 A 2010 meta-analysis limited to studies in middle-aged men found no association between total testosterone (TT) levels and CVD risk.28 However, a more recent meta-analysis involving a larger number of studies identified significant associations between androgen deficiency and increased risk of CVD and CVD mortality.29 It should be stressed, however, that the nature of these studies cannot prove causality. The possibility that low testosterone may be an epiphenomenon, marking poor general health rather than modulating CVD risk per se has to be explored.

Levine GN,  Steinke EE,  Bakaeen FG,  Bozkurt B,  Cheitlin MD,  Conti JB,  Foster E,  Jaarsma T,  Kloner RA,  Lange RA,  Lindau ST,  Maron BJ,  Moser DK,  Ohman EM,  Seftel AD,  Stewart WJ. Sexual activity and cardiovascular disease: a scientific statement from the American Heart Association, Circulation , 2012, vol. 125 (pg. 1058-1072)
The blood supply to your penis starts in your heart and flows through arteries in the belly to even smaller arteries that branch off to carry blood into the penis. With sexual stimulation, these blood vessels need to rapidly increase blood flow. If these blood vessels are blocked (atherosclerosis) by coronary artery disease, you may not be able to achieve or maintain an erection.11
Normal male sexual function requires a complex interaction of vascular, neurological, hormonal, and psychological systems. The initial obligatory event is acquisition and maintenance of an erect penis, which is a vascular phenomenon. Normal erections require blood flow into the corpora cavernosae and corpus spongiosum. As the blood accelerates, the pressure within the intracavernosal space increases dramatically to choke off penile venous outflow. This combination of increased intracavernosal blood flow and reduced venous outflow allows a man to acquire and maintain a firm erection.
Having chronically high blood pressure can affect overall satisfaction with sex and affect men’s ability to achieve a firm erection. Due to constant vessel damage as a result of high blood pressure, linings of the arteries begin to harden and narrow, a process called atherosclerosis. Because blood flow is limited to the affected regions of the body, arterial blood circulation to various organs—including the heart muscles, brain, and even the groin—can be compromised, with myocardial infarctions, strokes, and erectile difficulty being common in hypertensive patients. Studies show that approximately 30 percent of hypertensive patients reported having erectile dysfunction, and approximately 49 percent of men aged 40 to 79 had both high blood pressure and ED.
There have been some studies to suggest that a placebo effect that improves ED may work for some men. One study found that men taking an oral placebo pill showed as much improvement in ED symptoms as men who took actual medication to improve ED. Conversely, men who were given therapeutic suggestions to improve ED did not see signs of symptom improvement.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (66) | Google ScholarSee all References However, some researchers have questioned whether the strain of sexual activity can be compared accurately with standard types of physical activity and whether sexual activity is more closely related to episodes of anger or fear.85x85DeBusk, RF. Evaluating the cardiovascular tolerance for sex. Am J Cardiol. 2000; 86: 51F–56F

Relaxation of erectile tissue requires nitric oxide from nonadrenergic-noncholinergic neurons and the endothelium.21 Penile tissue from diabetic men with ED demonstrates impaired neurogenic and endothelium-mediated relaxation of smooth muscle,22 increased accumulation of advanced glycation end products (AGEs),23 and upregulation arginase, a competitor with nitric oxide synthase for its substrate L-arginine.24 Normal responses to direct smooth muscle relaxants in most of these studies implies that the impairments are due to decreased synthesis, release, or activity of nitric oxide. The fundamental mechanisms mediating these changes are thought to be the same as for other diabetic complications: increased polyol pathway flux, intracellular accumulation of AGEs, activation of protein kinase C, and increased flux through the hexosamine pathway.25
The links between hypertension and ED are increasingly recognized and the 2009 re-appraisal of European guidelines includes relevant statements.35,47 Erectile dysfunction is almost twice as frequent in hypertensive as in normotensive individuals and appears to be of higher severity. The relative risk of developing ED in hypertensive patients compared with normotensive individuals ranges from 1.3 to 6.9. Regarding pathophysiology, hypertension appears to cause ED per se, through a multitude of mechanisms that include prolonged exposure to elevated levels of systemic blood pressure, endothelial dysfunction, and circulation of vasoactive substance (with a pivotal role of angiotensin II) that lead to structural and functional alterations in the penile arteries. The largely unfounded (see earlier paragraph) notoriety of antihypertensive treatment for causing ED is one of the most predominant causes for non-adherence and discontinuation of antihypertensive therapy, and therefore, patients should be properly informed by physicians. Phosphodiesterase type 5 inhibitors are effective in hypertensive patients with ED and they can safely be co-administered with antihypertensive medication.39 Specifically for alpha-blockers, low starting doses of PDE5 inhibitors are preferred in patients already on alpha-blocker treatment, and likewise, low starting doses of alpha-blockers are encouraged in patients taking PDE5 inhibitors. Of clinical significance is that hypertensive men with ED are more likely to comply with their antihypertensive medication when under PDE5 inhibitors.
There are so many potential reasons a man might develop erectile dysfunction (ED), it's nearly impossible to generalize the best ways to treat it. What works for one man may not work for another simply because they are having problems for different reasons. That said, it may encouraging to hear that there are a variety of options that may be considered, from psychological counseling to lifestyle changes, medications to treatments and devices.
Abstract | PubMed | Scopus (136) | Google ScholarSee all References Other candidate mechanisms linking ED and cigarette smoking include hypercoagulability and increased platelet aggregation, increased release of free fatty acids and catecholamines, changes in NO synthetic pathways, and a possible direct toxic effect on vascular endothelium.13x13Chung, WS, Shim, BS, and Park, YY. Hemodynamic insult by vascular risk factors and pharmacologic erection in men with erectile dysfunction: Doppler sonography study. World J Urol. 2000; 18: 427–430
Erectile dysfunction is a common occurrence in men with diabetes. The incidence of erectile dysfunction increases progressively with age, from 5% in men age 20 to 75% in men over age 65. The cause of erectile dysfunction in men with diabetes is usually related to a decrease in the blood supply to the penis as well as to injury to the nerves that are responsible for the erection mechanism. A decrease in testosterone production has also been identified as the cause in some men with diabetes.