When it comes to scientific development, in Western medicine, an analytic approach is often used to identify and resolve medical challenges. A hypothesis is first derived through general observations of a phenomenon. A research plan is then carefully designed and data collected. Once sufficient data is collected, critical statistical evaluations are done and conclusions are drawn (4). Every aspects of a disease entity are studied from macroscopic to microscopic views, down to the cellular and molecular levels. The deep understanding of the role of cGMP-specific phosphodiesterase type 5 enzymes in ED and the use of phosphodiesterase-5 inhibitors in treatment of ED exemplifies the success of this approach.
The common associations between cardiovascular disease and ED have led some researchers to explore whether onset of ED can be an effective predictor of the presence of cardiovascular disease. A study of 40 patients with cardiac disease found an association between sexual dysfunction and the presence of cardiovascular disease, as well as a correlation between the severity of ED and the number of coronary arteries with extensive atherosclerosis.16x16Greenstein, A, Chen, J, Miller, H, Matzkin, H, Villa, Y, and Braf, Z. Does severity of ischemic coronary disease correlate with erectile function?. Int J Impot Res. 1997; 9: 123–126

Abstract | Full Text | Full Text PDF | PubMed | Scopus (46) | Google ScholarSee all References The Princeton Consensus Panel provided guidelines (Table 4) for physicians regarding patients who are being evaluated for their level of risk in resuming sexual activity.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


Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Since then, several other oral PDE-5 inhibitors have been developed, including vardenafil and tadalafil, which generated considerable interest in both the scientific and lay communities. There was also much concern about their safety, especially in men with cardiovascular disease. Compared with the 2 newer PDE-5 inhibitors vardenafil and tadalafil, sildenafil has been available for a much longer time; therefore, the vast majority of published cardiovascular safety studies have been performed on this medication. Recommended starting and maximum doses of oral PDE-5 inhibitors are shown in Table 1.
Abstract | Full Text PDF | PubMed | Scopus (16) | Google ScholarSee all References These medications cause intracavernosal pressure changes in animal models, and human studies have noted deleterious effects on erectile function, decreased libido, and ejaculatory problems.42x42Weiss, RJ. Effects of antihypertensive agents on sexual function. Am Fam Physician. 1991; 44: 2075–2082
Gazzaruso C,  Solerte SB,  Pujia A,  Coppola A,  Vezzoli M,  Salvucci F,  Valenti C,  Giustina A,  Garzaniti A. Erectile dysfunction as a predictor of cardiovascular events and death in diabetic patients with angiographically proven asymptomatic coronary artery disease: a potential protective role for statins and 5-phosphodiesterase inhibitors, J Am Coll Cardiol , 2008, vol. 51 (pg. 2040-2044)https://doi.org/10.1016/j.jacc.2007.10.069

While additional investigation is usually necessary, the medical and sexual history is essential and frequently the most revealing aspect of the ED assessment process. Questionnaires are an integral part of the history. The International Index of Erectile Function (IIEF), a 15-item, self-evaluation questionnaire is a validated instrument for assessing erectile function, orgasmic function, desire and satisfaction after sexual relations.8 An abridged version of the IIEF is a 5-item questionnaire the Sexual Health Inventory for Men (SHIM) or IIEF-5 (Table 2). Responses to the five questions range from 1 (worst) to 5 (best). Questions 2 to 4 may be graded 0 (if there is no sexual activity, or no sexual intercourse attempt) and the final score ranges from 1 to 25 points; a descending score indicates worsening of erectile function, with values ≤21 being diagnostic of ED.8 Importantly, validated questionnaires correlate with the extend of CAD9 and improve the predictive value of ED for total cardiovascular events compared with a single-question ED diagnosis.5 It cannot be overemphasized that the SHIM can be effectively used not only by andrologists and urologists but by a wide array of medical specialists, such as cardiologists, diabetologists, primary care physicians, etc.
Testosterone therapy in hypogonadism modulates metabolic components associated with CV risk. The majority of prospective clinical studies indicates that treatment achieving testosterone levels within physiological limits has beneficial or neutral effects on a lipid profile other than HDL-C, beneficial or neutral effects on inflammatory mediators, and generally beneficial effects on glycaemic state.25 The lean body mass is typically increased in hypogonadal subjects, and visceral adiposity is decreased in several studies and unchanged in the remainder. Such metabolic effects have raised interest on the potential impact on cardiovascular health. Regarding symptoms in patients with pre-existing cardiovascular conditions (angina or heart failure) TTh has been either neutral or beneficial.25 Regarding CVD risk, available clinical trial data indicate that the use of testosterone in middle-aged to elderly men does not increase cardiovascular risk25 with the exception of one study in very frail (substantial limitation of mobility and a high rate of comorbidities) elderly subjects that used an off-label high, and rapid escalation, dosing regimen.46 Prospective data from large, well-designed, long-term trials of TTh are warranted.
Crossref | PubMed | Scopus (174) | Google ScholarSee all References This study concluded that patients who have stable coronary artery disease who can exercise to 4.5 metabolic equivalents (METs) with a negative or mildly positive stress test and without angina or hypotension can safely take sildenafil. Physicians who prescribe sildenafil should counsel their patients that, if they have chest pain or other cardiac symptoms with sexual intercourse, they should not take nitrates and should immediately call their physician.66x66Jackson, G. Sexual intercourse and stable angina pectoris. Am J Cardiol. 2000; 86: 35F–37F
Erectile dysfunction (ED) can be treated by urologists or other specialists or even by your general practitioner. Your doctor may recommend medication that works by relaxing penis muscles and increasing blood flow into the penis. Other treatments include therapy, implants, surgery and lifestyle changes, like exercising regularly, losing weight and eating right.
Before taking any medication for erectile dysfunction, including over-the-counter supplements and herbal remedies, get your doctor's OK. Medications for erectile dysfunction do not work in all men and might be less effective in certain conditions, such as after prostate surgery or if you have diabetes. Some medications might also be dangerous if you:
Unlike intraurethral suppositories, intracavernosal injection (IC) injection of vasoactive agents such as PGE-1 has consistently been shown to be effective in the treatment of ED in men with diabetes. In a study of 336 men with diabetes-related ED, 83% of patients reported erections satisfactory for intercourse after IC injection of PGE-1.55 Unfortunately, 24% of these patients also reported penile pain, one of the most common side effects of IC injection therapy. Other studies have noted similar effectiveness rates.56,57
In the early years of my cardiology practice, I was surprised by the number of men with heart disease who also suffered from impotence. In fact, being incapable of having an erection was the norm rather than the exception after heart attack. In those days, impotence was widely attributed to the psychological depression that often followed heart attack.
In diabetic patients who fail medical management of ED, penile implantation surgery remains a viable therapeutic option. In a recent review of 372 men who underwent implantation of a three-piece inflatable penile implant, 86% reported that the device was still functional 5 years after implantation, and 79% reported that they used the device at least twice monthly.59

For those patients who cannot take erectile dysfunction medications, the authors counsel that an exercise training regimen may be an appropriate substitute therapy to enhance sexual function and quality of life. The authors stress that clinicians should focus on the sexual activity history of chronic heart failure patients and not ignore it, since addressing this element can substantially improve their quality of life.


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
Crucial to the understanding of the relationship between ED and CVD and the management of ED patients within the context of the (potential) CVD were the consecutive Princeton Consensus Recommendations (I: 2000, II: 2005, and III: 2012). The reader is strongly encouraged to refer to the most recent, third (2012) Princeton Consensus.30 Key notions in the assessment and management of the patient with organic ED are that (i) he should be considered at increased CVD risk until recommended checks suggest otherwise, and (ii) ED identifies increased CVD risk in the presence or absence of CVD symptoms or history.

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.
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