In 1989, the Third National Symposium on Cardiac Function in Pulmonary Heart Disease in Wuhan formulated the diagnostic criteria for pulmonary hypertension in China: that is, breathing air at sea level, the systolic pulmonary artery pressure >30 mmHg and the mean pulmonary artery pressure >20 mmHg in the resting state; the mean pulmonary artery pressure >30 mmHg in the exercise state as the national unified diagnostic criteria for pulmonary hypertension. At present, this criterion is still adopted in China. According to the degree of pulmonary hypertension, pulmonary hypertension can be divided into mild, moderate and severe levels. Treatment: Timely surgery to correct intracardiac malformations in congenital heart disease combined with pulmonary hypertension can prevent further development of pulmonary hypertension, and the original lesions can gradually subside after surgery, therefore, cardiac surgery for infants and children should be strongly advocated. If the lesion has developed to an irreversible stage, even if the intracardiac malformation is surgically corrected, pulmonary hypertension still persists and develops further, eventually forming Eisenmenger syndrome. In a study of 21 patients with Eisenmenger syndrome, Roberts et al. found that inhalation of 100 oxygen increased arterial oxygen saturation, decreased mPAP, and improved cardiac index. Whether oxygen inhalation helps prolong life is still debated. Early studies found that patients on long-term oxygen had a higher 5-year survival rate than those without oxygen. However, a study by Sandoval et al. found that long-term oxygenation did not extend the life span of patients with Eisenmenger syndrome. In addition to the many inconveniences of home oxygen, medical institutions have different opinions on whether oxygen should be used as long-term treatment.2. Anticoagulation therapy; anticoagulation therapy has an important role in the treatment of chronic pulmonary vascular embolic pulmonary hypertension. In addition, anticoagulation therapy may improve the survival rate of patients with primary pulmonary arterial hypertension. Studies have shown that without anticoagulation, the survival rate at 3 years after diagnosis of primary pulmonary hypertension is 31%, whereas with anticoagulation, the survival rate at 3 years after diagnosis of primary pulmonary hypertension increases to 62%. Therefore, anticoagulants are routinely used as adjunctive therapy in primary pulmonary hypertension. In primary pulmonary hypertension, embolic lesions are likely to occur in the pulmonary vasculature due to low patient activity, slow blood flow, increased erythropoiesis, and blood concentration. Thrombin is partially activated, coupled with endothelial hypofunction, the cyanogen monoxide and prostacyclin (PGI ) released is reduced, platelets are prone to adhesion and coagulation. The main drug used in anticoagulation therapy is warfarin. It inhibits the activity of these enzymes by competing with vitamin K and binding to enzyme proteins so that the activation of coagulation factors I, VII, IX, and X by these enzymes is inhibited. Heparoxol inhibits the action of prothrombin by enhancing the action of antithrombin III. In addition, heparin has the effect of inhibiting platelet coagulation.3. Vasodilator drugs: As in the early stages of pulmonary hypertension. Pulmonary vasoconstriction plays an important role, so vasodilator drugs can reduce pulmonary artery pressure by diastolic pulmonary vessels. The goal of treatment is to reduce both pulmonary vascular resistance and pulmonary artery pressure. The goal of treatment is to reduce pulmonary vascular resistance and pulmonary artery pressure without causing major changes in systemic hemodynamics. The main drugs used are calcium channel antagonists, prostacyclin and nitric oxide.3,1 Calcium channel antagonists: In pulmonary hypertension, the diastolic effect of calcium channel antagonists on the pulmonary vasculature is stronger than the diastolic effect on other vessels because of increased pulmonary vascular tone. Calcium channel antagonists are more effective for primary pulmonary hypertension, while for secondary pulmonary hypertension it depends on what the underlying disease is. For example, calcium channel antagonists are more effective in pulmonary hypertension caused by connective tissue disease and less effective in pulmonary hypertension caused by chronic obstructive pulmonary disease. When the pre-dose pulmonary artery pressure is higher, the efficacy of the drug is poorer. This may be due to the fact that the higher the pulmonary artery pressure, the more severe the underlying disease and the pathological changes that have developed, so that the efficacy of vasodilator drugs alone is shy. In the past, when calcium channel antagonists were applied, the same dose was often used as in the treatment of hypertension and angina pectoris. However, the short-term efficacy is still possible, but the long-term efficacy is not good. Currently, the use of high doses of calcium channel antagonists is advocated, and the doses are gradually increased from small doses to achieve the most appropriate dose for each patient (dose individualization). With this approach, calcium channel antagonists are the most effective daily drug for the treatment of pulmonary hypertension. A recent meta-trial synthesized the results of eight trials of long-term calcium channel antagonists. It was concluded that (1) seven of the eight trials showed a decrease in pulmonary artery pressure (2) a significant decrease in pulmonary artery pressure was observed when high doses were used. (3) Subjective symptom improvement was consistent with a decrease in pulmonary artery pressure Recent 5-year follow-up of 64 patients with primary pulmonary hypertension showed that 94 patients in the calcium channel antagonist group survived longer than 5 years, while only 38% of patients in the non-treatment group survived longer than 5 years. In the treatment of pulmonary hypertension – the most commonly used drug is nifedipine. Recent results have shown that long-acting calcium channel antagonists (e.g., amlodipine, felodipine) are also effective in the treatment of pulmonary hypertension. When using calcium channel antagonists, attention should be paid to their side effects, such as hypotension, negative muscle effects, etc. 3.2 Prostacyclin: Prostacyclin is a metabolite of arachidonic acid and is mainly produced by the vascular endothelium. Prostacyclin binds to its receptor and activates adenylate cyclase. The concentration of intracellular cyclic adenosine monophosphate (cAMP) increases, thus exerting a vasodilating effect. Prostacyclin also inhibits platelet coagulation and vascular smooth muscle proliferation] Studies have shown that prostacyclin production by the vascular endothelium is reduced in pulmonary hypertension. Therefore, exogenous application of prostacyclin is actually an alternative therapy. Prostacyclin is mainly used in primary pulmonary hypertension to reduce pulmonary vascular resistance and pulmonary artery pressure, improve right heart function and pulmonary artery pathology, improve exercise tolerance, and increase survival rates. Procyclidine is also effective in some secondary pulmonary hypertension, such as persistent pulmonary hypertension in newborns, adult respiratory distress syndrome, and pulmonary hypertension caused by connective tissue disease. However, it is less effective in pulmonary hypertension due to chronic obstructive pulmonary disease. Due to the short half-life of prostacyclin (only 2-3 minutes). Therefore, it needs to be administered continuously by intravenous drip or by means of a buried pump. The starting dose of prostacyclin is 2ng/(kg/min), which is increased by 2ng/(kg/min) every 1O-15 minutes until the maximum dose []5~20ng/(kg-min)] or side effects occur. When the pulmonary artery pressure returns to normal, prostacyclin can be gradually discontinued and the efficacy of the treatment can be maintained with the application of calcitriol antagonists. To overcome the disadvantages of continuous intravenous infusion, daily analogues of prostacyclin and prostacyclin are now available in the form of nebulized inhalation. 3.3 Inhaled nitric oxide: Nitric oxide is an endothelial-derived vasodilator. In primary pulmonary hypertension and secondary marshal hypertension from various causes, endothelial production of nitric oxide is reduced. Nitric oxide inhalation may act as a replacement therapy. Krypton monoxide exerts a vasodilating effect by activating guanylate cyclase, which increases the concentration of guanosine cyclophosphate (cGMP). When nebulized, nitric oxide is highly lipid soluble, so it reaches the pulmonary circulation through the alveoli and is inactivated before it reaches the body. Therefore, nitric oxide inhalation has the effect of selective pulmonary vasodilatation. Nitric oxide inhalation can be used for the treatment of secondary pulmonary hypertension, persistent pulmonary hypertension in newborns, and pulmonary hypertension caused by extracorporeal circulation surgery, etc. In adult patients with respiratory distress syndrome, nitric oxide inhalation can reduce pulmonary artery pressure and increase pycnogenic oxygen content. Nitric oxide inhalation can also be used before and after cardiopulmonary surgery to reduce pulmonary vascular resistance. Nitric oxide inhalation commonly used wattle amount is 10~40×IO (ppm). >There is no greater benefit than 8O×10 (ppm). Problems to be noted are: (1) The drug may increase the bleeding time (by inhibiting platelet adhesion and coagulation). (2) The drug has some negative inotropic effects. (3) Harmful toxic metabolites may be formed. 3.4 Phosphodiesterase inhibitors: Phosphodiesterase inhibitors increase cAMP concentration by inhibiting cAMP breakdown. The drug has the effect of reducing pulmonary artery pressure and pulmonary vascular resistance. The representative drugs are amrinone and milrinone. The drug has a positive inotropic effect and lower blood pressure.3.5 Endothelin receptor antagonists: endothelin 1 (ET- 1) is by far the most powerful vasoconstrictor known. Studies have shown that increased plasma ET levels in patients with PAH are negatively correlated with prognosis. Bosentan, a dual blocker of endothelin receptors, is the first FDA-approved endothelin receptor antagonist for the treatment of pulmonary arterial hypertension. Recent studies have found that the oral formulation of bosentan. It is easy to use. It is safe and effective in the treatment of pulmonary hypertension. It can effectively improve endurance and improve hemodynamic indices. 3.6 Sildenafil: Sildenafil is a type 5 phosphodiesterase inhibitor, which can selectively dilate the pulmonary artery, and was approved by the FDA in June 2005 for the treatment of pulmonary arterial hypertension. A number of studies have confirmed that sildenafil can effectively improve the clinical symptoms of patients with pulmonary hypertension. It is a highly selective pulmonary vasodilator, which can effectively reduce pulmonary artery pressure and pulmonary circulatory resistance, increase cardiac output and cardiac index, and improve cardiac function without adversely affecting the body circulation. Sildenafil also has the advantages of oral administration and relatively low cost of treatment. In addition, digitalis preparations and diuretics can increase cardiac output with short-term sedation of digitalis preparations, but the efficacy of long-term use in pulmonary arterial hypertension is not yet certain, and diuretics can control the development of tissue edema in patients. In conclusion, although many new advances have been made in the treatment of pulmonary hypertension in recent years, there is still a lack of very effective means (lack of valid evidence-based medical evidence).