Erection is a neurovascular event that involves spinal and supra spinal pathways. The final common pathway involves the release of nitric oxide (NO) from both endothelial cells and neurons, which acts as a vasodilator causing penile engorgement and erection. NO is degraded by the enzyme phosphodiesterase (PDE) type 5 in the penis. Erectile dysfunction (ED), defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance, results when the neurovascular pathway is interrupted by medical conditions or drugs. A 15-item self-administered questionnaire, the International Index of Erectile Function (IIEF), is one of the most useful tools to evaluate erectile function (EF) in clinical trials, although of much less use in routine clinical practice. The MMAS (Massachusetts Male Aging Study) was the first major epidemiological investigation to study the prevalence of ED. The study found that ED was three times more common in patients with diabetes mellitus. The aetiopathogenesis of ED in diabetes is multifactorial, with vascular and neural factors being equally implicated. Hyperglycaemia is believed to give rise to biochemical perturbations that lead to these microvascular changes. In the MMAS, ED in diabetes was strongly correlated with glycaemic control, duration of disease and diabetic complications. The incidence increased with increasing age, duration of diabetes and deteriorating metabolic control, and was higher in individuals with type 2 diabetes than those with type 1.ED in men with diabetes often affects their quality of life and, as patients are often reluctant to come forward with their symptoms, a carefully taken history is one of the most useful approaches in identifying affected individuals. The PDE inhibitors have revolutionised the management of ED and oral drug therapy is currently first-line therapy for the condition. These agents act by potentiating the action of intracavernosal NO, thereby leading to a more sustained erection. Sildenafil was the first PDE5 inhibitor to undergo evaluation and has been studied extensively. More recently two other agents, vardenafil and tadalafil, have been introduced. All the drugs have been shown to be effective across a wide range of aetiologies of ED, including diabetes. The drugs have been shown to improve EF domain scores, penetration and maintenance of erection, resulting in more successful intercourse. Their effects are greater at higher doses. Sildenafil and vardenafil are shorter-acting agents, while tadalafil has a longer half-life allowing the user more flexibility in sexual activity. Common adverse effects include headache, nasal congestion and dyspepsia, all actions related to inhibition of PDE5. The drugs are generally well tolerated and withdrawal from the clinical studies as a result of drug-related adverse effects were rare. The use of PDE5 inhibitors in the presence of oral nitrates is absolutely contraindicated. The clinical studies to date have not evaluated the use of one drug in the case of treatment failure with another agent. Sublingual apomorphine, which stimulates central neurogenic pathways, is a new agent and may be a suitable alternative in those patients in whom PDE5 inhibitors are ineffective or contraindicated. In clinical trials, all IIEF domains except sexual desire were found to have improved after apomorphine. The median times to erection in these studies were 18.9 and 18.8 minutes for the 2 and 3mg doses, respectively. Intraurethral and intracavernosal alprostadil may be a useful alternative when oral drug therapy is ineffective or contraindicated. The management of ED in the diabetic patient may often involve a multidisciplinary approach where psychosexual counselling and specialist urologist advice is required in addition to the skills and expertise of the diabetologist. Finally, the introduction of the new oral agents have completely revolutionised the management of ED and allowed more individuals to come forward for treatment.
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
Abstract | PubMed | Scopus (136) | Google ScholarSee all References Attainment and maintenance of a firm erection requires good arterial inflow of blood and efficient trapping of venous outflow. Therefore, disease processes that affect the function of the arterial and venous systems would be expected to negatively affect erectile function. Unfortunately, cardiovascular disease is also prevalent in the male population and is especially evident with increasing age. The interplay of cardiovascular health and sexual function includes the risk of cardiac events precipitated by the physical exertion of sexual activity and by some medications, such as sildenafil, on the cardiovascular system. An estimated 500,000 patients survive a myocardial infarction each year in the United States, and an estimated 11 million patients have existing cardiovascular disease, making the issue of sexual function and cardiac disease relevant to many patients.8x8Muller, JE, Mittleman, A, Maclure, M, Sherwood, JB, Tofler, GH, and Determinants of Myocardial Infarction Onset Study Investigators. Triggering myocardial infarction by sexual activity: low absolute risk and prevention by regular physical exertion. JAMA. 1996; 275: 1405–1409
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Sildenafil is taken orally 1 hour before anticipated sexual intercourse and enhances the normal response to sexual stimulation; however, it has no effect on erections in the absence of stimulation.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
The wide range of prevalence rates noted among the studies can be attributed to a number of factors. First, prevalence rates are affected by the sensitivity and specificity of methods used to assess ED.1 In addition, a number of these studies used medical record review to identify patients with ED, as opposed to anonymous patient reports. It has been shown in other disease states that patients tend to underreport ED when questioned directly by their providers.3 Therefore, the use of validated questionnaires that are either self-administered in an anonymous, neutral setting or administered by an objective third-party interviewer are preferred.
PubMed | Google ScholarSee all References However, other studies have noted that, when blood pressure levels are monitored after initiation of antihypertensive therapy, changes in blood pressure level are not correlated with sexual function.38x38Rosen, RC, Kostis, JB, Jekelis, A, and Taska, LS. Sexual sequelae of antihypertensive drugs: treatment effects on self-report and physiological measures in middle-aged male hypertensives. Arch Sex Behav. 1994; 23: 135–152
The wide range of prevalence rates noted among the studies can be attributed to a number of factors. First, prevalence rates are affected by the sensitivity and specificity of methods used to assess ED.1 In addition, a number of these studies used medical record review to identify patients with ED, as opposed to anonymous patient reports. It has been shown in other disease states that patients tend to underreport ED when questioned directly by their providers.3 Therefore, the use of validated questionnaires that are either self-administered in an anonymous, neutral setting or administered by an objective third-party interviewer are preferred.

Second-generation cardioselective beta-blockers (atenolol, metoprolol, bisoprolol, etc.) can also lead to ED. Atenolol was shown to cause significant reduction of sexual activity compared with placebo in a double-blind, parallel-arm study.22 The same study also showed a significant reduction in testosterone levels with atenolol versus valsartan. An open, prospective study of hypertensive men treated with atenolol, metoprolol and bisoprolol for at least 6 months showed high prevalence of ED – approaching 66 % – in these patients.23
A penile prosthesis is another treatment option for men with erectile dysfunction. These devices are either malleable (bendable) or inflatable. The simplest type of prosthesis consists of a pair of malleable rods surgically implanted within the erection chambers of the penis. With this type of implant the penis is always semi-rigid and merely needs to be lifted or adjusted into the erect position to initiate sex. Today, many men choose a hydraulic, inflatable prosthesis, which allows a man to have an erection whenever he chooses and is much easier to conceal. It is also more natural.
Several drugs can produce erectile difficulties, but blood pressure drugs are near the top. ED is an occasional side effect of BP drugs like thiazide diuretics, loop diuretics, and beta-blockers, all of which can decrease blood flow to the penis and make it difficult to get an erection. However, other BP drugs, such as alpha-blockers, ACE inhibitors, and angioten-sin-receptor blockers, rarely cause ED.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (272) | Google ScholarSee all References Most adverse effects are mild and are related primarily to vasodilation (headache, flushing, nasal congestion), gastrointestinal disturbances (dyspepsia), or retinal effects such as vision changes.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
Crossref | PubMed | Scopus (47) | Google ScholarSee all References Because of this perceived increase in risk, many couples are concerned about resuming sexual activity in the setting of cardiac disease. A study that monitored male patients after coronary artery bypass grafting found that 17% of patients and 35% of their partners were afraid of resuming sexual activity.1x1Muller, JE. Sexual activity as a trigger for cardiovascular events: what is the risk?. Am J Cardiol. 1999; 84: 2N–5N
Evaluation of functional capacity is the mainstay for the management of patients with ED.30 However, it should be kept in mind that in men with heart failure sexual activity may affect the heart differently from physical activity of similar METS due to differences in psychological anticipation and sympathetic activation.30,49 Cardiac echocardiography may offer valuable information for left ventricular performance and valvular function. For risk categories of heart failure patients and their management, please refer to Table 3 and Figure 5.
• Medications: About 25 percent of ED cases are caused by drugs. Many medications, including common medicines prescribed for diabetes and its complications, can cause ED. The most common offenders are blood pressure drugs, antihistamines, antidepressants, tranquilizers, appetite suppressants, and cimetidine (an ulcer drug). In addition, over-the-counter medications, including certain eye drops and nose drops, have been associated with ED. That does not mean you should stop taking these medications! Rather, you should discuss them with your doctor to determine whether a different dosage, an alternate medicine, or additional treatments will resolve the ED.
Undoubtedly, heart disease is and will continue to be one of the major health problems of modern society. Approximately one death every forty seconds occurs due to cardiovascular (CV) disease in the United States alone and arterial hypertension is one of the greatest culprits for it[1]. Considering the fact that around 25% of the global population suffer from arterial hypertension, predicted to reach 1.5 billion people in the foreseeable future, it is easily deducted that a respectful part of the general population is under major and constant CV risk[2,3].
Eastern medicine should be fully exploited, and integrated with modern medicine to combine the advantages of both TCM and Western medicine. More research should be conducted into the efficacy and safety of TCM, and integration of TCM and Western medicine may provide promising breakthroughs in future clinical treatment. This strategy may allow for the development of new therapeutic strategies based on concepts of TCM and integrated medicine. There is a need for multimodal therapy and holistic approach to treat men (and their partners) with ED through complementary use of herbal supplements and modern drug to optimize underlying medical comorbidities; acupuncture, exercise or massage to reduce stress and strengthen the body; introduction and escalation of various medical therapy with use of mechanical therapy to further enhance penile erection; and lastly surgical intervention in suboptimal or refractory ED cases.
Due to their vasorelaxing effect, administration of PDE-5 inhibitors in hypertensive individuals was initially confronted with great suspicion. A wealth of clinical data however has proven that PDE-5 inhibitors are associated with few side effects and provoke a small and insignificant reduction in blood pressure with minimal heart rate alterations in both normotensive and hypertensive patients as well. As a matter of fact, they can be safely and effectively administered to hypertensive individuals even when they are already taking multiple antihypertensive agents[51-56]. The sole exception to the rule is co-administration with organic nitrates, which is an absolute contraindication due to profound and possibly hazardous hypotension effect[57,58]. Moreover, precaution should be taken when PDE-5 inhibitors are combined with a-blockers where, due to possible orthostatic hypotension effect, lower starting doses should be implemented in the therapeutic regime[59-62].
Diabetes mellitus is associated with both decreased erectile function and increased cardiovascular risk. The MMAS found that the age-adjusted probability of complete impotence was 3 times higher in patients with diabetes mellitus than in those without the disease.6x6Kloner, RA. Erectile dysfunction and cardiovascular risk factors. Hosp Pract (Off Ed). 2001; 36: 41–44 (49-51.)

Patients who use this therapy should be trained under the guidance of a urologist, and sterile technique must be used. The drugs must be injected into the shaft of the penis and into one of the penile erectile bodies (corpus cavernosum) 10–15 min before intercourse. Most patients do not complain of pain upon injection. Sexual stimulation is not required, and resulting erections may last for hours. Side effects include penile pain and priapism. The cost is about $12–20 per injection.
Montorsi P,  Ravagnani PM,  Galli S,  Rotatori F,  Veglia F,  Briganti A,  Salonia A,  Dehò F,  Rigatti P,  Montorsi F,  Fiorentini C. Association between erectile dysfunction and coronary artery disease. Role of coronary clinical presentation and extent of coronary vessels involvement: the COBRA trial, Eur Heart J , 2006, vol. 27 (pg. 2632-2639)https://doi.org/10.1093/eurheartj/ehl142
Abstract | PubMed | Scopus (136) | Google ScholarSee all References In a prospective review of 3250 men aged 26 to 83 years without ED at their first examination, total cholesterol and high-density lipoprotein (HDL) cholesterol levels were found to be strongly predictive of onset of ED after controlling for age, diabetes mellitus, stress level, cardiovascular disease, and prostate disease.25x25Wei, M, Macera, CA, Davis, DR, Hornung, CA, Nankin, HR, and Blair, SN. Total cholesterol and high density lipoprotein cholesterol as important predictors of erectile dysfunction. Am J Epidemiol. 1994; 140: 930–937

• Blood Vessels: Diabetes damages blood vessels, especially the smallest blood vessels such as those in the penis. Diabetes can also cause heart disease and other circulatory problems. Proper blood flow is absolutely crucial to achieving erection. “Erection is a hydraulic phenomenon that occurs involuntarily,” says Arturo Rolla, MD, of Harvard University School of Medicine. “Nobody can will an erection!” Anything that limits or impairs blood flow can interfere with the ability to achieve an erection, no matter how strong one’s sexual desire.
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