I. Introduction Erectile dysfunction (ED) is a common and frequent disease in adult men. Survey shows that the incidence of ED in men aged 40 to 70 is 50%, and the number of ED patients in China can reach more than 100 million, but less than 10% of ED patients seek medical treatment. Many patients are affected by the traditional concept of thought and ashamed to speak out. Patients are afraid that treatment will bring trauma is also a factor. ED is not life-threatening, but it affects men’s physical and mental health, and affects the couple’s relationship and family harmony. Since 1998, when the safe and effective oral drug sildenafil became available, men’s erectile dysfunction has received increasing attention. Due to the lack of uniform diagnostic and treatment standards, which makes clinical work difficult, it is necessary to develop a guideline for the diagnosis and treatment of erectile dysfunction suitable for Chinese male patients. In view of this, we refer to the relevant literature and take into account the specific situation of China to prepare this guideline. This guideline only briefly explains the diagnosis and treatment methods, and the specific operation methods should be referred to the relevant literature. With the increase of clinical experience and the progress of research in this field, this guideline will be updated periodically. （Definition of Erectile Dysfunction Erectile Dysfunction (ED) refers to a man’s persistent or recurrent inability to achieve or maintain an erection of sufficient hardness to complete satisfactory sexual intercourse under sexual stimulation. Formerly referred to as “impotence”, it was replaced by the term “erectile dysfunction” due to its lack of specificity and pejorative connotations, and the term erectile dysfunction is now globally accepted. It is important to note that erectile dysfunction can only be diagnosed if the disease has been present for at least 6 months. However, in the case of traumatic or surgical erectile dysfunction, the duration of the disease may be less than 6 months. Erectile dysfunction needs to be differentiated from other male sexual dysfunctions, including decreased libido, ejaculation disorders, and orgasmic disorders. (b) Physiology of erection, etiology and classification of erectile dysfunction (1) Physiology of erection Penile erection is a process of hemodynamic changes in the corpus cavernosum of the penis under the regulation of neuro-endocrine. When sexually stimulated, non-adrenergic non-cholinergic neurons secrete nitric oxide (NO) and other neuromediators. Nitric oxide enters into the smooth muscle cells of penile corpus cavernosum and activates guanylate cyclase, which converts guanosine triphosphate to the second messenger, guanosine cyclic phosphate (cGMP). The increase in intracellular cGMP concentration leads to relaxation of cavernous smooth muscle, distension of the penile cavernous sinus, and increased arterial blood flow. The volume of the cavernous body of the penis increases, the white membrane surrounding the cavernous body of the penis is passively extended and elongated, so that the subxiphoid conduit vein, which drains blood from the corpus cavernosum, is compressed and extended and narrowed, and the resistance to venous return is increased, and the hardness of the penis increases, leading to erection of the penis. As cGMP is degraded by smooth muscle intracellular phosphodiesterase type V (PDE5) and loses its activity as well as the sympathetic nerves return to tenseness after ejaculation, the penis transitions to a state of weakness. Because PDE5 is selectively distributed in the cavernous smooth muscle of the penis, cGMP-specific PDE5 inhibitors are currently the oral drug of choice for the treatment of erectile dysfunction. Prostaglandin E1 intracavernous penile injection is used for the treatment of erectile dysfunction, and its mechanism of action is to increase cAMP synthesis through activation of adenylate cyclase, which induces relaxation of penile cavernous smooth muscle and induces penile erection. In addition, adrenergic neuromediated contraction of penile cavernous smooth muscle cells, decreased penile blood flow, and open venous return produce penile weakness. Phentolamine, an a-adrenergic receptor blocker, is used in penile cavernous injection therapy for erectile dysfunction. 2, causes and classification of erectile dysfunction The normal erectile function of the penis requires the cooperation of vascular, neurological, psychological, hormonal and cavernous factors. Abnormalities in any of these factors can lead to erectile dysfunction. Erectile dysfunction is usually categorized into three types according to the cause: organic ED (arterial, venous, neurological and endocrine, etc.), psychological ED and mixed ED (organic causes and psychological factors co-exist). In the past, it was believed that ED was mainly caused by psychological factors, and after the 1980s, more and more information showed that more than 50% of ED was caused by organic factors. In China, due to the influence of traditional concepts, ED patients are often mixed with psychological factors. Second, the diagnosis of erectile dysfunction and assessment of key points (Table 3) (a), medical history 1, sexual history The diagnosis of erectile dysfunction is mainly based on the patient’s complaints, but most patients are difficult to speak. Choose a relaxed and privacy-protecting environment to inform patients that ED is a common disease, explaining that ED often shares many risk factors with cardiovascular disease, such as hypertension, dyslipidemia and smoking, etc., and that the diagnosis and treatment of ED may reveal clues to clinically asymptomatic but progressing diseases (e.g., coronary artery disease, etc.), and emphasize that there are many effective and simple methods available for the treatment of ED. Enable patients to discuss erectile dysfunction openly. A sexual function questionnaire (CIEF-5, Table 1) can also be given to patients with a certain level of education (junior high school or above) so that the patient has time to come forward individually to answer the questions before talking to the physician, facilitating further understanding of the patient’s sexual history. The patient’s needs, expectations, and preferences for various treatments should be understood through contact with the patient. Also, the patient’s spouse should be involved in the diagnosis, evaluation, and treatment of the ED patient whenever possible. Table 2 lists some of the questions commonly used to ask about sexual life history for reference. Sexual history should focus on: ED onset, duration, progression and severity, objective feedback from the spouse about his/her ED, nocturnal or morning erection status, self-stimulation and visual and auditory sexual stimulation induced erection status. Sexual desire, erection hardness and erection duration, whether ejaculation is too fast or too slow, whether there is orgasm, genital pain caused by sexual intercourse, spouse’s sexual function 2, past medical history, medication history, and poor lifestyle Recent studies have shown that most of the ED is closely related to some common systemic diseases, medications, and lifestyle, and that in some cases, several etiological factors or risk factors may be present at the same time. Systemic diseases Systemic diseases: cardiovascular disease, hypertension, diabetes mellitus, liver and kidney dysfunction, etc. Neurologic disorders: multiple sclerosis, cerebral atrophy, etc. Penile disorders: painful penile sclerosis, etc. Psychological disorders: depression, tension and anxiety, etc. Endocrine abnormalities: abnormal thyroid function, hypogonadism, hyperprolactinemia, etc. Surgery and trauma Neurological injuries: spinal cord injury. Pelvic injury: injury, surgery, pelvic radiotherapy. Perineal injuries: radical prostatectomy, TURP, etc. Drugs and poor lifestyle Prescription drugs: antihypertensives, cardiac drugs, central nervous system drugs, hypoglycemic drugs, tricyclic antidepressants, nonsteroidal anti-inflammatory drugs, etc. Smoking Alcoholism Drug abuse (2) Physical examination Every patient with ED should undergo a comprehensive physical examination. Physical examination should be combined with medical history, the key examination should include: general condition, body type and secondary sexual characteristics; external genitalia and genitourinary system: focus on the penis, scrotum, testicles and anorectal examination. Cardiovascular system: check the cardiovascular function (including blood pressure and heart rate, etc.), as well as the blood supply of the lower extremities, such as dorsalis pedis arterial pulsation, etc.; Neurological system: via the system check should pay particular attention to the lumbosacral region, lower extremities, perianal and perineal sensations and other parts of the content; (C), laboratory tests 1, basic laboratory tests Basic laboratory tests for the mandatory inspection items. Blood routine. Urine analysis and microscopy. Blood biochemistry: including blood glucose, liver and kidney function and blood lipids. Endocrine laboratory examination According to the risk factors suggested by the patient’s medical history and combined with the patient’s specific situation and local medical conditions to choose the relevant examination. Hypothalamic-pituitary-gonadal axis function test. Measurement of blood testosterone, prolactin (PRL), follicle stimulating hormone (FSH) and luteinizing hormone (LH), etc.; glucose tolerance test; thyroid function measurement. (d) Special tests and evaluation Since the introduction of the safe and effective oral drug sildenafil (Viagra), most patients can choose to use the oral drug sildenafil first line of treatment before the implementation of special tests. Special investigations are often used when oral medications are ineffective and the cause needs to be identified, when vascular surgery is required, when the patient asks for the cause to be identified, or when a legal traffic accident assessment is involved, and special investigations are performed selectively as needed. The attending physician should consider the need to consult relevant specialists (e.g., psychological, diabetic, cardiovascular, etc.). The rationale for the special examination and the significance of a positive result should be explained to the patient, and the examination should be carried out on the basis of a full understanding of the patient’s goals and informed consent. In addition, the conditions of the hospital should be taken into account. It is recommended that special tests be performed by a specialist. Special tests include: assessment of psychosomatic factors; nocturnal erection test; penile cavernous injection drug test; penile color Doppler ultrasound; dynamic drug penile cavernous perfusion and contrast; penile arteriography; penile cavernous nuclear imaging; neurological examination: such as penile sensory threshold, bulbocavernosus reflex threshold, penile cavernous electromyography, somatosensory evoked potentials, and sphincter electromyography. Neurological examination: such as penile sensory threshold measurement, bulbocavernosus reflex threshold measurement, penile cavernosus electromyography, somatosensory evoked potentials and sphincter electromyography. The main points of erectile dysfunction treatment (Table 4) Ideal ED treatment principles: safety, effectiveness, simplicity and economy. The choice of ED treatment should take into account personal, cultural, ethical, religious, and financial affordability factors. The first step in treatment is to inform the patient and his/her spouse about the ED and test results, and to determine the needs, preferences, etc. of the patient and his/her spouse. Emphasis should be placed on the presence of organic etiology and psychological factors related to ED. In addition, the sexual function of the spouse should be considered before starting treatment. Whenever possible, patients and their spouses should be informed of all treatments suitable for them, as well as their respective advantages and disadvantages and costs, so that patients and their spouses can actively participate in the choice of treatment. This specification adopts a graded approach to treatment, with the principles of grading based on: convenience; reversibility; invasiveness; and cost. All treatments should be followed up over time to determine their effectiveness and safety. In addition, when a new treatment method emerges, it should be compared with existing treatments in terms of effectiveness and safety as well as price ratio. (i) Correcting risk factors and strengthening primary treatment Usually, before taking direct treatment, the first step is to correct modifiable risk factors and primary diseases (diabetes mellitus, hypertension, dyslipidemia, etc.), which is more useful for some patients. Modifiable risk factors include: lifestyle and psychosocial factors. Lifestyle such as smoking, alcoholism, drug dependence etc. need to be managed accordingly. Psychosocial factors include gender-related problems such as dysphoria, lack of sexual knowledge and experience, and depression and anxiety. Sexual skills and knowledge of sexual medicine Prescription and over-the-counter medications Certain anti-hypertensives, anti-arrhythmics, and psychotropic medications such as antidepressants, anti-androgens, and steroids may affect erectile function. Changing the dosage or type of medication may be very helpful for some patients, but this needs to be addressed in consultation with the physician treating the primary condition. Hormone Replacement Therapy Hormone replacement therapy is indicated for recognized hormone deficiencies such as androgen deficiency and hypogonadism. However, hormone supplementation does not necessarily improve erections. Elderly people should be thoroughly screened for signs of prostate cancer by rectal fingerprinting, ultrasound, and blood PSA test before androgen replacement therapy, and followed up regularly. (ii) Sex counseling and sex education Sex counseling and sex education, such as psychosexual therapy or couple therapy, can be used for patients with psychological factors that may affect sexual function. （Oral medications Oral medications have the advantages of being non-invasive, easy to use, efficacious and easily accepted by most patients, and are currently used as the first line of treatment for erectile dysfunction. However, attention should be paid to certain specific contraindications, such as sildenafil is contraindicated with nitrate drugs. According to the mechanism of action, oral drugs can be divided into: central triggering agent: the main effect of the central nervous system to induce erection, such as apomorphine, testosterone preparations. Peripheral inducers: mainly act in the periphery to induce erection, such as yohimbine, phentolamine, etc.. Central modulators: improve the internal environment of the central nervous system and enhance erection, e.g. Methuselah and Phentolamine. Peripheral modulators: improve the local/systemic internal environment and enhance erection, e.g. sildenafil analogs and methotrexate. Selective phosphodiesterase type V inhibitors: Phosphodiesterase type V (PDE5) is the phosphodiesterase isoform distributed mainly in the smooth muscle of the penile corpus cavernosum, which has the ability to degrade the second messenger of intracellular NO ~ cyclic guanosine monophosphate (cGMP) and reduce its concentration, so as to make the penis turn into a weak state. Therefore, inhibiting the activity of PDE5 can increase the concentration of cGMP and enhance the erectile function of the penis. Sildenafil is effective only in the presence of sexual stimulation because sexual stimulation induces the release of N from the corpus cavernosum of the penis to promote the biosynthesis of cGMP. Numerous clinical trials have demonstrated that sildenafil (Viagra) is a selective PDE5 inhibitor that is safe and effective in clinical use, and is currently the oral drug of choice for the treatment of erectile dysfunction. There are also Cialis and Vardenafil currently in clinical trials. Sildenafil produced by Pfizer Pharmaceutical Company has been approved by many countries for the treatment of erectile dysfunction, and was listed on the market in China in June 2000 under the trade name of “Wan Ai Ke”. Phase II clinical studies have shown that Wan Ai Ke is effective for patients with ED of various etiologies, different degrees, and different ages, with a clinical effectiveness rate of about 85%. The clinical effectiveness of Viagra is about 85%. Doctors should instruct patients to start with 50mg and adjust the dose to 100mg or 25mg if necessary; however, it should be emphasized that sildenafil is contraindicated in combination with nitrates, as severe hypotension and adverse events may occur. Side effects include transient headache, facial flushing, dyspepsia, nasal congestion, and transient visual abnormalities (due to inhibition of phosphodiesterase type VI), all of which are transient in nature and occur in no more than 10% of cases. Apomorphine Hydrochloride Container Tablets Apomorphine is a dopamine receptor agonist in the central nervous system and enhances penile erectile function. UPRIMA 2-3 mg sublingually before intercourse has an onset of action usually in 20 minutes and is reported to be 50%-60% effective in erectile dysfunction. The main side effect is nausea, but it is less severe at lower doses (2mg and 4mg). Other side effects include dizziness, sweating, drowsiness, and yawning, which occur in about 10% of cases. Fainting occurs in rare cases. The drug is currently marketed in the EU under the trade names Uprima (Abbott) and Ixense (Takeda), and the domestic drug (Hainan Dahua Pharmaceuticals) is under Phase II clinical observation. Phentolamine Phentolamine is an alpha-adrenergic receptor blocker with both central and peripheral effects, suitable for mild to moderate ED treatment, with a reported efficacy rate of about 50%. Side effects include dizziness, nasal congestion and tachycardia, which can be tolerated at the 40mg dose. Several domestic pharmaceutical companies produce such drugs and have been on the market. The combination of oral drugs may have additive or synergistic effects, and side effects may be aggravated, so further clinical observation is needed to fully consider its efficacy and safety. Other drugs. At present, there are a variety of Chinese medicinal preparations on the domestic market, including those used in the treatment of ED, but the exact pharmacological mechanism of these drugs is still unclear, and there is a lack of large-sample randomized, double-blind, placebo-controlled multi-center clinical research data. (D) topical drugs Currently domestic marketed topical drugs named Bifar, containing prostaglandin E1 1mg plus special transdermal agent mixture made of cream, the drug absorbed through the urethra into the cavernous body of the penis, by increasing the concentration of cAMP in the cavernous body of the penis smooth muscle and induced penile erection. Clinical studies have proved that the clinical effectiveness of Bifal cream 0.3-1.0mg dropped through the urethra 10-20 minutes before sexual intercourse is about 70%. Side effects include penile distension, urethral burning sensation, no systemic side effects. (E) Vacuum negative pressure erection device and narrowing ring Vacuum negative pressure narrowing ring device is suitable for patients who do not want to use medication and contraindication of drug treatment. The use of hollow cylinders at the root of the penis through the negative pressure of the blood into the cavernous body of the penis, and then use a rubber band at the root of the penis to block the venous return to maintain penile erection. Side effects include: penile pain, numbness, bruising and difficulty in ejaculation. Advantages: non-invasive, economical, can be used repeatedly. Disadvantages: more troublesome to use. (F), penile cavernous body drug injection therapy One or more of the first-line therapy failure, poor efficacy and side effects of patients, but also due to patient preference and the use of penile cavernous body drug injection therapy as a second-line treatment. The main methods include: intracavernous injection of vasoactive drugs to induce an erection to complete sexual intercourse, which was widely used in the past, but with wide variations in efficacy, greater side effects, higher costs, and high rates of treatment interruption. Vasoactive drugs, direct relaxation of the penile cavernous smooth muscle and make the penis erect, commonly used drugs are prostaglandin E1 (listed drugs are Caverject, Kaiser, etc.), poppy and phentolamine, etc. Recently, more use of prostaglandin E1, can be a single drug, but also a combination of drugs, the efficacy of the majority of patients with accurate and safe and reliable, but the rate of interruption of the higher. Side effects include pain at the injection site (around 30%), abnormal erections and possible cavernous fibrosis after prolonged use. Abnormal erection is the most serious complication, therefore, this treatment must be used under the supervision of an experienced physician. This treatment is contraindicated in patients with sickle cell anemia and other patients who are prone to abnormal erection and should be treated urgently if abnormal erection occurs. Advantages of the treatment include: efficacy, safety and rapid onset of action. Disadvantages include: invasive treatment and high cost. (G) Surgical treatment of erectile dysfunction 1, vascular surgery, including penile artery reconstruction and vein ligation surgery, is suitable for the treatment of vascular ED in some young people, but it is necessary to strictly control the indications for surgery. Generally, these patients need special examination. Currently, the success rate of vascular surgery is reported to be between 40% and 70% in the near future, but the long-term effect is not good. 2, penile prosthesis implantation Penile prosthesis implantation surgery through the penile cavernous body surgical implantation of erection device, to assist penile erection to complete sexual life of semi-permanent treatment, applicable to various methods of treatment is ineffective in patients with severe ED. This kind of traumatic treatment method, for irreversible final treatment options, in addition to preoperative consideration of surgical complications (infection, erosion and collateral damage, etc.) and mechanical complications, but also take into account the patient’s ability to afford the price, the complication rate of about 5% -10%. (H), review and follow-up Each ED patient receiving treatment should be regularly reviewed and follow-up. Follow-up visits include: doctor-patient communication, relieve the patient’s concerns, sex education, adjusting the treatment of comorbidities and medication, discovering other sexual dysfunctions, verifying the use of medication and adjusting the dose of medication, and changing the appropriate treatment method. Systemic examination to identify other underlying conditions associated with ED Psychosocial assessment. P.S. Treatment of patients with ED associated with cardiovascular risk factors ED significantly affects quality of life, but is not life threatening. It is recognized that a significant proportion of ED patients have comorbid cardiovascular disease. Since sexual activity is an excitatory physical activity, which is inappropriate for some patients with cardiovascular disease, patients with cardiovascular disease should be emphasized to carefully assess the overall cardiovascular function status of the patient before treatment and when restoring sexual function. Generally, patients can be categorized into patients with low-risk factors, patients with medium-risk factors and patients with high-risk factors according to their cardiovascular function status and then treated accordingly. Patients with low-risk factors and treatment Low-risk factors are: Asymptomatic, <3 cardiovascular risk factors (age, hypertension, diabetes mellitus, obesity, smoking, and dyslipidemia) Accompanied by poor lifestyle Controlled hypertension Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild/stable angina Mild heart valve disease Mild/stable angina Mild/stable angina Mild/stable angina Primary treatment ED first-line therapy Regular follow-up Patients with intermediate risk factors and treatment recommendations Intermediate risk factors are defined as: More than 3 cardiovascular disease risk factors (excluding gender) Moderate/stable angina pectoris Infarction at 2-6 weeks Heart failure (cardiac NYHA class II) Other atherosclerotic diseases such as cerebrovascular accidents, peripheral vascular disease Treatment recommendations Specific cardiovascular investigations (e.g., exercise testing, echocardiography) are performed. Based on the results of the cardiovascular examination, patients will be categorized as low-risk or high-risk and treated accordingly. Patients with high-risk factors and treatment recommendations High-risk factors refer to: Unstable angina Uncontrolled hypertension Heart failure (cardiac function NYHA class III/IV) Cardiac infarction within 2 weeks (cerebrovascular accident) Severe arrhythmia Hypertrophic or other cardiomyopathies Moderate cardiac valvular disease Treatment recommendations Cardiovascular disease treatment is the first priority Cardiac function stabilization can be considered only after expert assessment of the sexual function of treatment