Disease name:
Introduction:
Pulmonary hypertension refers to those with a mean pulmonary artery pressure >3.33 kPa (25 mmHg) or >4 kPa (30 mmHg) during exercise.
Cause:
(1) Causes of the disease
1. Increased pulmonary blood flow
(1) Congenital cardiovascular abnormalities of left-to-right shunt: atrial septal defect, ventricular septal defect, patent ductus arteriosus, permanent arterial trunk.
(2) acquired intracardiac shunt: aortic aneurysm rupture or aortic Valsalva aneurysm broke into the right ventricle or right atrium, ventricular septal perforation (defect) after myocardial infarction.
2. Increased vascular resistance around the lungs
(1) Pulmonary vascular bed reduction: pulmonary embolism caused by various causes.
(2) pulmonary artery wall lesions:
1 pulmonary arteritis: Raynaud's syndrome, scleroderma, localized intradermal calcium deposition, Raynaud's phenomenon, finger scleroderma and telangiectasis syndrome (CREST syndrome), rheumatoid arthritis, systemic erythema Lupus, polyneuritis, dermatomyositis, granulomatous arteritis, eosinophilia, arteritis.
2 primary pulmonary hypertension: plexus pulmonary vascular disease, microthrombus formation, pulmonary vein occlusion disease.
3 pulmonary artery congenital stenosis.
(3) pulmonary fibrosis or interstitial granuloma: diffuse pulmonary interstitial fibrosis, radiation pulmonary fibrosis, miliary tuberculosis, pneumoconiosis,Lung cancer,Cystic fibrosis, idiopathic hemosiderosis and so on.
(4) pulmonary vasospasm caused by hypoxemia:
1 chronic obstructive pulmonary disease: chronic bronchitis, emphysema, bronchial asthma.
2 respiratory dyskinesia: pleural disease, thoracic deformity, multiple polio, muscle atrophy, obesity.
3 plateau lack of oxygen.
(5) changes in blood viscosity: increased plasma viscosity,PolycythemiaIncreased red blood cell accumulation and increased red blood cell hardness.
3. Increased pulmonary venous pressure
(1) pulmonary vein occlusion: mediastinal tumor or granulomatosis, mediastinal inflammation, congenital pulmonary vein stenosis.
(2) Heart disease: left ventricular dysfunction, mitral stenosis or insufficiency, mitral annulus calcification, left atrial myxoma, three-female heart.
(two) pathogenesis
1. Pathogenesis The pulmonary circulation includes the right ventricle, pulmonary artery, capillaries, and pulmonary veins. Its main function is to exchange gas. Hemodynamics have the following four characteristics: 1 low pressure: pulmonary artery pressure is 19/16mmHg at normal resting, average pressure is (12±2) mmHg, systolic blood pressure is less than 25mmHg, 1/6 of aorta, lung The vascular perfusion pressure is also low, the pressure difference between the pulmonary artery and the left heart chamber is only 6mmHg, which is l/7～1/10 of the normal aortic pressure; 2 the resistance is small: due to short pulmonary vessels, thin wall, large degree of expansion, blood flow The resistance is small. Normal human pulmonary vascular resistance is 1/5 ~ l/10 of systemic resistance; 3 fast flow rate: the lung receives all the blood from the heart, but the process is much shorter than the systemic circulation, so the flow rate is fast; 4 capacity is large: pulmonary vascular bed It is large in size and can hold 900mL of blood, accounting for 9% of the whole blood.
Pulmonary artery pressure = pulmonary vascular resistance × pulmonary blood flow + left atrial pressure
Therefore, pulmonary hypertension is determined by pulmonary vascular resistance, pulmonary blood flow, and left atrial pressure. The pulmonary artery consists of three types of caliber and structural vessels, namely elastic arteries with an outer diameter of >1000 μm, muscle arteries between 100 and 1,000 μm and small arteries with an outer diameter of <100 pμm. Muscular arteries and small arteries affect pulmonary artery pressure. Important part. The formation mechanism of pulmonary arterial pressure is very complicated and can be divided into the following cases:
(1) High-dynamic pulmonary hypertension (increased pulmonary blood flow): Due to the low resistance, low pressure and high volume of the pulmonary circulation, the pulmonary blood vessels can adapt to the increase of pulmonary blood volume without causing significant fluctuations in pulmonary arterial pressure, but there are certain limits. When the blood output is increased by 2 to 3 times, the average pulmonary artery pressure is only increased by 20% to 50%. When the blood pressure is increased by 4 to 5 times, the pulmonary artery pressure can be increased by 1 time. If the long-term continuous increase in blood flow causes the blood vessels to dilate, it can cause changes in the structure of the pulmonary artery and become irreversible. Pulmonary hypertension caused by increased pulmonary blood flow is more common in congenital heart disease with left-to-right shunt or large arteriovenous fistula (Eisenmenger syndrome). At rest, the pulmonary circulation pressure is mostly normal, and the cardiac output increases significantly during exercise. If the vasospasm or vascular bed is reduced, and the compensatory expansion of the vascular volume is limited, the pulmonary artery pressure rises sharply.
(2) High-resistance pulmonary hypertension (increased vascular resistance around the lungs):
1 pulmonary vascular bed reduction: pulmonary vascular reserve capacity, large expansion, when the vascular bed is reduced by more than 70%, significant pulmonary hypertension will occur.
A. Extravascular compression: various diffuse pulmonary interstitial lesions such as pulmonary fibrosis, pulmonary granuloma and pulmonary infiltration, caused by bronchial tension changes, increased alveolar pressure, scar tissue contraction, lung tissue swelling or Tumor compression, etc., narrow and occlude small blood vessels in the lungs.
B. Causes of blood vessels itself: severe emphysema, alveolar septum rupture, many alveoli fuse into large bubbles, the capillaries are stretched and slender, or by the vascular wall itself inflammation or invasive lesions, small arterial intimal hyperplasia and middle layer hypertrophy.
C. Endovascular embolization: occlusion of pulmonary arterioles after arteritis, as well as pulmonary artery trunk and small vessel embolization or thrombosis.
2 pulmonary vasoconstriction: pulmonary vasoconstriction is the most important cause of increased pulmonary hypertension. Hypoxemia is a strong stimulating factor that causes pulmonary capillary contraction, which causes an increase in vascular resistance, leading to pulmonary hypertension. Pulmonary hypertension is closely related to pulmonary oxygen saturation (SaO2) in patients with chronic obstructive pulmonary disease (COPD). When SaO2<80%, 2/3 patients have elevated pulmonary arterial pressure, and SaO2<75% has 95.4. % of patients have elevated pulmonary arterial pressure. High altitude pulmonary hypertension is also caused by hypoxia. The oxygen content in the air is related to the altitude. At an altitude of 3400m, the partial pressure of oxygen in the air is 100mmHg, and the altitude of the air is 5000m. The partial pressure of oxygen in the air is 80mmHg. Acute pulmonary edema can occur in the early high altitude due to acute hypoxia, causing an increase in irreversible pulmonary hypertension. Pulmonary vasoconstriction caused by hypoxia may be related to the following factors:
A. Autonomic nervous mechanism: pulmonary vasculature is governed by adrenergic sympathetic and cholinergic parasympathetic nerves. Adrenergic alpha and beta receptors are present around the pulmonary arterioles. When the oxygen partial pressure in the blood decreases, the partial pressure of carbon dioxide rises. When the ion concentration is increased, the impulse is transmitted to the sympathetic center of the hypothalamus by stimulating the aorta and carotid sinus, and the pulmonary artery is contracted by reflex. In the case of acidosis, the vascular response to hypoxia contraction is significantly increased.
B. Humoral factors: In the absence of oxygen, the proliferation of mast cells in the lungs increases, the ability to produce histamine is enhanced, degranulation occurs, and histamine and serotonin are released, which directly affects the cell membrane, causing the loss of intracellular potassium ions. Increased calcium levels lead to increased muscle excitability. Prostaglandins are elevated in the lungs during hypoxia. Prostaglandin F2a (PGF2a) and thromboxane (TXA2) are potent pulmonary vasoconstrictors, which directly affect the excitation and contraction of calcium ions on smooth muscle and can cause platelets. Agglutination promotes thrombosis and increases vascular resistance. In the absence of oxygen, the activity of angiotensin I converting enzyme in the lung is increased, which causes angiotensin II to increase, causing pulmonary vasoconstriction. Increased systemic circulation pressure is also an important cause of increased pulmonary artery pressure;
C. Cellular factors: ATP production is reduced in hypoxia, and cell membrane ATPase activity is decreased, causing potassium sputum sodium to be lost in pulmonary artery smooth muscle, causing a decrease in negative membrane potential and increasing muscle excitability. At the same time, in the hypoxic acid poisoning, the free calcium ions in the blood increase, which promotes the entry of calcium ions into the smooth muscle cells, and initiates the contraction device, which can cause the blood vessels to contract, and the resistance increases, leading to pulmonary hypertension.
3 pulmonary vascular elasticity is reduced: long-term hypoxia causes persistent pulmonary contraction or bronchial inflammation to affect pulmonary arterioles, which can cause organic vascular damage, especially small arteries with an inner diameter of 300 μm or less, causing smooth muscle edema, degeneration, necrosis, and elasticity. Plate rupture and endothelial cell and elastic tissue hyperplasia, fibrosis, and even luminal occlusion, resulting in thickening and stiffness of the vessel wall. The mesenteric muscle layer of the pulmonary arterioles with a diameter of less than 80 μm can reduce the compliance of the wall and increase the vascular resistance.
4 increased blood viscosity: visible in primary polycythemia or long-term hypoxia caused by secondary polycythemia to increase blood viscosity. When the hematocrit is >50%, the pulmonary vascular resistance is increased.
(3) pulmonary venous hypertension (post-capillary pulmonary hypertension): due to the characteristics of pulmonary circulation, the pressure difference between pulmonary arteries and veins is very small, only 2 ~ 10mmHg, so some diseases cause pulmonary hypertension to increase when pulmonary venous pressure is increased. Common in mitral valve disease, three-atrial heart, left atrial myxoma, can also occur in long-term left ventricular dysfunction, left ventricular responsiveness and so on. When the pulmonary venous pressure is elevated, the pulmonary arterioles are reactively contracted or occur in the basal fibrosis of the lungs, which causes the pulmonary vascular bed to be squeezed, which is also the cause of pulmonary hypertension. A slight increase in left atrial pressure has little effect on pulmonary artery pressure, and a one-fold increase will affect pulmonary artery pressure.
2. Pathological changes Pulmonary arterial hypertension caused by any cause can cause anatomical and structural changes of pulmonary arterioles and muscular small arteries, thickening of the wall and stenosis of the lumen, and partial local atrophy as long as there is sufficient severity and time. The lumen expansion, in terms of pathological morphology, is mainly divided into four categories:
(1) plexus pulmonary artery disease: this type is most common in left-to-right shunt congenital heart disease, also seen in pulmonary artery blood from the aortic branch of pulmonary isolation and typical primary pulmonary hypertension, occasionally in the liver Hardened portal hypertension, portal vein thrombosis and schistosomiasis, AIDS, etc. Histology is characterized by muscular hypertrophy of the pulmonary artery, intimal hyperplasia, formation of conjunctival fibrosis, constriction of the lumen, arterialization of the arteries, vasodilator lesions, cellulose-like necrosis and formation of plexiform lesions. The blood vessels of this site are limitedly dilated. The wall of the tube is composed of only a thin elastic membrane to form a dilated blood vessel, which is prone to thrombosis. The thrombotic endothelial cells enter the thrombus to form a cavernous hemangioma.
(2) embolic and thrombotic pulmonary vascular disease: the muscle layer of the pulmonary artery is often not obvious, there are new and old thrombosis, thrombosis after the formation of eccentric plaque-like intimal fibrosis, and then the formation of fiber spacing.
(3) pulmonary venous hypertension pulmonary vascular disease: any disease that can block venous blood flow can cause similar pulmonary vascular disease, such as mitral valve disease, left atrial myxoma, left heart failure and mediastinal fibrosis, etc. Involved pulmonary arteries, muscle arteries, arterioles, lymphatic vessels, lung tissue are also involved, muscle type of pulmonary artery hypertrophy, arterialization of the arteries, severe intimal fibrosis, thickened arterialization of the pulmonary veins and intimal fibrosis.
(4) Hypoxic pulmonary hypertension pulmonary vascular disease: pulmonary vascular disease is mainly limited to smaller blood vessels, the arterioles are mechanized, the intima has longitudinal smooth muscle cell bundles or layers, similar lesions can also be seen in venules, larger muscles. The type of pulmonary artery may be normal or slightly moderately thick.
symptom:
1. Symptoms include symptoms of primary disease and symptoms caused by pulmonary hypertension. Pulmonary hypertension itself is non-specific, mild pulmonary hypertension can be asymptomatic, and can progress as the disease progresses:
(1) Labor dyspnea: due to decreased pulmonary vascular compliance, cardiac output cannot increase with exercise, and dyspnea after physical activity is often the earliest symptom of pulmonary hypertension.
(2) fatigue: the result of hypoxia due to decreased cardiac output.
(3) syncope: caused by a sudden decrease in blood supply to the brain tissue, usually after exercise or sudden rise, but also due to occlusion of the pulmonary artery by a large embolism, sudden arrhythmia or arrhythmia.
(4) angina pectoris or chest pain: coronary artery perfusion is reduced due to right ventricular hypertrophy, and myocardial relative blood supply is insufficient. Chest pain may also be caused by an expansion of the main trunk or main branch of the pulmonary artery.
(5) hemoptysis: pulmonary hypertension can cause microvascular aneurysm rupture and hemoptysis at the beginning of pulmonary capillaries.
(6) hoarseness: pulmonary artery expansion caused by recurrent laryngeal nerve.
2. Signs When the pulmonary artery pressure is significantly increased, the right atrium is enlarged, and the following signs may appear in right heart failure: the jugular vein a wave is obvious, the pulmonary valve area is pulsating, the right ventricular lift pulsation, and the pulmonary valve area systolic jet murmur. Tricuspid systolic reflux murmur, right ventricular third, 4 heart sounds, right heart failure can occur after jugular vein engorgement, liver enlargement, positive jugular vein venous sign, lower extremity edema. Severe pulmonary hypertension, decreased cardiac output, weak pulse and low blood pressure.
Early clinical symptoms of pulmonary hypertension are atypical and often misdiagnosed or missed. In order to obtain early diagnosis, it is necessary to closely combine clinical manifestations, signs and laboratory tests. According to different situations, non-invasive or traumatic examination methods should be used. Firstly, there is no pulmonary hypertension, and then the severity is determined. Finally, it is determined whether it is primary or secondary. Hairy.
1. Be wary of early symptoms of fatigue, labor dyspnea and syncope can not be considered as non-specific manifestations of chronic diseases, it may be the earliest manifestations of patients with pulmonary hypertension.
2. Special signs can suggest causes such as sitting breathing, paroxysmal nocturnal dyspnea, lung squeaky squeak and pleural effusion, suggesting that pulmonary hypertension is caused by post-capillary lesions; heart murmur can determine rheumatic valvular disease or Caused by congenital heart disease; body vascular murmur may be aortitis; pulmonary vascular murmur suggests pulmonary stenosis through the bloodstream, may have thrombosis or pulmonary arteriovenous fistula in this area.
3. Full use of non-invasive examination of electrocardiogram with left atrial or left ventricular hypertrophy suggesting that pulmonary hypertension may be cardiogenic; X-ray chest radiograph shows large pulmonary venous flow redistribution or Kerley's B line reflects pulmonary venous hypertension, pulmonary hypertension Occurred in left-to-right shunt heart disease; echocardiography can accurately diagnose pulmonary hypertension caused by certain heart disease; lung function test can help identify obstructive or restrictive lung disease; blood gas analysis can distinguish whether hypoxic pulmonary hypertension Radionuclide can show thromboembolic pulmonary hypertension in the lung segment and above.
4. Right heart catheterization is the most reliable method to check the severity and reversibility of pulmonary hypertension, which is helpful for the diagnosis of etiologies, such as elevated pulmonary capillary wedge pressure, indicating post-capillary pulmonary hypertension. The blood oxygen content of the site can be found to be left to right. Thrombosis, vascular malformations, hypoplasia or stenosis can also be detected by selective pulmonary angiography.
5. Lung tissue biopsy with the above exclusion diagnosis is still unable to determine the cause of pulmonary hypertension, may be chronic recurrent pulmonary thromboembolism, pulmonary venous occlusive disease and primary pulmonary hypertension, lung biopsy can be identified.
diagnosis:
Attention should be paid to the identification of primary and secondary pulmonary hypertension:
1.Secondary pulmonary hypertension Patients who have caused right heart hypertrophy, strain or right heart failure are more likely to diagnose PH, but the patient's condition is often critical, and it has reached the late stage of the disease, treatment is difficult, and the prognosis is not good. Therefore, early diagnosis of pulmonary hypertension should be done to find the cause of pulmonary hypertension.
Congenital heart disease and chronic lung disease are common causes of pulmonary hypertension. Heart murmurs can help determine congenital heart disease or rheumatic valvular disease, but the original heart murmur may be reduced or disappeared during pulmonary hypertension. The pulmonary electrocardiogram of the pulmonary hypertension is characterized by excessive systolic load in the right ventricle. If there is a left atrial or left ventricular hypertrophy, the cause of pulmonary hypertension may be cardiogenic. X-ray examination is also characteristic and helps to find the cause of pulmonary hypertension. X-ray diagnosis of lung parenchymal disease is evident, large pulmonary venous blood redistribution and Kerleys B line reflecting pulmonary venous hypertension. Pulmonary blood increase is mainly seen in left to right shunt congenital heart disease. Mitral stenosis, enlargement of the left atrium and valvular calcification. Echocardiography can accurately determine the extent of pulmonary hypertension and changes in cardiac structure. Right heart catheterization measures the extent of pulmonary hypertension and estimates whether it is reversible. Selective pulmonary angiography (including DSA) to find thrombosis, vascular malformations, hypoplasia or stenosis. Lung biopsy is also feasible for unexplained pulmonary hypertension to further confirm the diagnosis.
2. Primary pulmonary hypertension Any patient with unexplained exercise dyspnea, fainting during exercise, should be suspected of the disease. If P2 is reluctant, combined with X-ray, electrocardiogram, echocardiography and cardiac catheterization, the diagnosis can be confirmed after the exclusion of congenital heart disease.
complication:
Chronic obstructive emphysema, chronic pulmonary heart disease, right heart failure and other complications may occur. pulmonary hypertension
treatment:
(a) treatment
1. Etiology treatment In addition to a small number of primary pulmonary hypertension, the vast majority of pulmonary hypertension is secondary. Pulmonary hypertension is reversible after the primary disease is cured in the early stages of pulmonary hypertension. In the advanced stage, pulmonary hypertension was reduced after primary disease control. Such as COPD should actively control infection, use bronchodilator drugs, drainage and drainage, improve ventilation; pulmonary thromboembolism should be treated with anticoagulant; pulmonary connective tissue disease or collagen disease should be treated with corticosteroids; mitral valve may be feasible valve replacement or valve Dilatation; septal defect or patent ductus arteriosus defect repair or catheter ligation and suture, active correction of heart failure are the key to the treatment of pulmonary hypertension.
2. The purpose of vasodilator therapy is to reduce the pulmonary artery pressure, increase the cardiac output, relieve symptoms, and enhance physical strength. The ideal pulmonary vasodilator should be selective relaxation of pulmonary vascular smooth muscle and relieve bronchospasm, improving ventilation and increasing PaO2. However, the current clinical application of vasodilator drugs have a strong effect on systemic circulation, thus affecting arterial blood pressure, and even causing PaO2 to decline. Therefore, it is best to perform cardiac catheterization before determining long-term application of vasodilators to observe blood flow in acute drug trials. The kinetic effect, if the pulmonary vascular resistance is reduced by more than 20%, the cardiac output is increased or unchanged, the pulmonary artery pressure is decreased or unchanged, and the systemic blood pressure is not changed or decreased enough to cause side effects, and can be taken for a long time. After 3 to 6 months of treatment, the cardiac catheter or non-invasive examination should be reviewed to understand the long-term effects of the drug. If the indications should be used early, the pulmonary vascular resistance can be significantly reduced. When most of the pulmonary stenosis or occlusion is advanced, At that time, the use of vasodilator drugs can only reduce the resistance of the systemic circulation and is more likely to cause hypotension.
(1) Drugs for direct expansion of pulmonary vascular smooth muscle: commonly used drugs are hydralazine (pyridazine), sodium nitroprusside, nitroglycerin and long-acting nitrate preparations.
1 肼 嗪 :: can directly relax smooth muscle, reduce peripheral resistance, reduce cardiac afterload, cardiac output increased. Its advantages: oral and injection effects are almost the same, long-term use of patients with better effect, increased cardiac ejection, mitral regurgitation, increased ejection fraction, decreased mitral regurgitation, increased pulmonary capillary wedge after exercise The pressure is reduced. In patients with chronic pulmonary heart disease, not only the cardiac output increased, but also the arteriovenous oxygen pressure difference decreased, and the mean pulmonary artery pressure decreased. The usage is 10 ~ 25mg, 3 times / d, then increased to 50mg, once every 6 hours; intramuscular injection or intravenous injection dose of 20mg each time as appropriate, not more than 200mg per day is appropriate.
2 Sodium nitroprusside: is a potent, short-acting, fast-acting, low-toxic vasodilator that relaxes arteries and veins, reduces systemic circulation and pulmonary circulation resistance, and increases myocardial perfusion and oxygen supply. Usage To avoid low blood pressure, start with a small dose, first intravenous infusion of 15μg / min, every 5 ~ 10min increase ineffective, each increase of 5 ~ 10μg / min, the general dose of 25 ~ 250μg / min, the highest The dose was 300 μg/min. Because the decrease of body arterial pressure is more obvious than the decrease of pulmonary artery pressure, the action time is short, and it must be administered intravenously, which limits the clinical application.
3 Nitroglycerin: It is a powerful dilating agent for smooth muscle. It has obvious effects on the veins, the pulmonary vascular bed is dilated, and the pulmonary artery pressure is decreased. Usage is sublingual, 0.3mg / time, according to the condition can also be intravenous infusion, the effect of pulmonary hypertension with coronary heart disease or hypertension is good.
(2) α-blockers: commonly used drugs are phentolamine, tolazoline (tortazone), phenoxybenzamine, etc., which can selectively block α receptors, cause blood vessels to dilate, blood pressure drops, Pulmonary artery and peripheral vascular resistance are reduced and can relieve bronchospasm.
Phentolamine is mainly used to dilate arteries, and it also dilates veins. It has a short duration of action and can be used for reversible pulmonary hypertension. Acute attacks with hypertension are more effective. After Marcelle gave this drug to 10 patients with pulmonary heart disease, the mean pulmonary artery pressure decreased by 35% and pulmonary vascular resistance decreased by 22%.
(3) β-receptor stimulants: commonly used drugs such as isoproterenol, terbutaline (t-butanthine), dobutamine and the like. The main role is to excite the myocardium, increase cardiac output, bronchial spasm, and dilated vasculature, so it has a better effect on pulmonary hypertension caused by bronchial asthma or wheezing bronchitis.
(4) Calcium antagonists: nifedipine (nifedipine), diltiazem (thiazepinone), verapamil, nicardipine, which can block the Ca2 channel of vascular smooth muscle cell membrane and relax vascular smooth muscle In order to reduce pulmonary vascular resistance and pulmonary hypertension, it can also relax bronchial smooth muscle, reduce airway resistance, improve ventilation function, and therefore better effect on hypoxic pulmonary hypertension. Commonly used amount: nifedipine l0mg, diltiazem 30mg, verapamil 40 ~ 80mg, both times / d.
(5) Angiotensin converting enzyme inhibitor:Captopril(巯甲丙脯酸),Enalapril(Phenyl butyl phthalate) and the like. By inhibiting the activity of angiotensin-converting enzyme, the adrenergic-angiotensin-aldosterone system is blocked, the production of angiotensin II and aldosterone is reduced, the peripheral blood vessels are dilated, the resistance is reduced, and long-term administration does not produce drug resistance. Captopril (caprolactam) is usually used in an amount of 25 mg, 3 times / d, and the maximum dosage is not more than 150 to 400 mg per day.
(6) Prostaglandins: alprostadil (prostaglandin E1), E2 (PGF2), epoprostenol (Prostacyclin) is a strong peripheral vasodilator that reduces peripheral vascular resistance. In addition, anti-platelet aggregation can reduce pulmonary vascular resistance and pulmonary arteriolar resistance, and decrease pulmonary artery pressure.
(7) Others: aminophylline, acetylcholine, salvia miltiorrhiza, ligustrazine, and tetrandrine (Halfrolactam) can also reduce blood viscosity, improve microcirculation, and reduce pulmonary vascular resistance.
3. Long-term oxygen therapy Long-term oxygen therapy means that the daily oxygen supply is >15h, for several months or several years, and the nasal congestion method or intratracheal oxygen supply method can be used. COPD is the main cause of hypoxic pulmonary hypertension. Oxygen therapy can correct hypoxemia. As PaO2 rises, pulmonary artery spasm caused by hypoxia relieves, pulmonary artery pressure decreases, pulmonary blood flow increases, and hypoxia correction also relaxes the bronchus. Function can improve ventilation. Weitzenblum et al observed the effect of long-term oxygen therapy on pulmonary hypertension induced by COPD. The mean pulmonary artery pressure increased (1.47±2.3) mmHg per year before oxygen therapy. After 1 year of oxygen therapy, the mean pulmonary artery pressure decreased (2.15±4.5) mmHg per year. It can be seen that long-term oxygen therapy has a special effect on reversible pulmonary hypertension.
4. Anticoagulant therapy is the key to anticoagulant therapy for pulmonary hypertension caused by pulmonary embolism. Correct and timely use of anticoagulant therapy can reverse pulmonary hypertension and prevent recurrence of pulmonary embolism, pulmonary hypertension caused by primary and congenital heart disease, anticoagulant therapy. There is also a certain effect.
5. Inhalation of nitric oxide In recent years, the relationship between nitric oxide (NO) and pulmonary hypertension has been deepened, providing a new means for the treatment of pulmonary hypertension. NO, endothelium-derived relaxing factor (EDRF), is mainly produced in vascular endothelial cells and is highly lipophilic and easily passes through the cell membrane. When it enters the smooth muscle cell membrane, it activates guanylate activating enzyme, which increases cGMP, and thus the pulmonary blood vessels dilate and the pulmonary artery pressure decreases. When acute or chronic hypoxia causes damage to the vascular endothelium, NO production is reduced, causing an increase in pulmonary arterial pressure. Inhalation of NO can also achieve pulmonary vasodilatation. Due to the short half-life of NO (2~4s), it is easily inactivated by hemoglobin. Therefore, only the pulmonary vessels are dilated after inhaling NO, and there is no effect on systemic circulation. Inhalation of NO only dilates the blood vessels in a well-ventilated area, thereby correcting the V/Q ratio and increasing the oxygenation ability. The effect is fast, and it takes effect when inhaled for lmin. Excessive concentration may cause lung injury, and the inhalation concentration is preferably 5 to 80 mg/L (5 to 80 ppm). The combination of NO and O2 will form toxic N02. In the application, the NO tube will be inserted into the end of the trachea to reduce the time of contact with O2 and reduce the oxygen concentration. Long-term efficacy, drug resistance, and safety are yet to be further studied.
6. Gene therapy is late, and cell technology and molecular biology studies have found that some growth factors and cytokines are involved in the pathogenesis of pulmonary hypertension. Gene transfer technology and antisense technology are new methods for treating pulmonary hypertension. The antisense endothelin or angiotensin gene is introduced to inhibit the overexpression of endothelin and angiotensin to inhibit vasoconstriction. For example, the regulation of various growth factors at the genetic level is expected to control the development of the disease.
(two) prognosis
The prognosis of pulmonary hypertension depends on the successful treatment of underlying disease. In general, the prognosis of primary pulmonary hypertension is poor, and the survival time is less than 3 years from the time of diagnosis. However, reports of long-term survival with calcium channel blockers and prostacyclin have also been reported. At present, there is too little experience with endothelin antagonists, and it is impossible to conclude the survival improvement. Patients who are not actively treated may eventually die of worsening right heart failure unless they are transplanted.
prevention:
Secondary pulmonary hypertension is associated with congenital heart disease, and the current cause of primary pulmonary hypertension is still unclear. The occurrence of congenital heart disease is a comprehensive result of various factors. In order to prevent the occurrence of congenital heart disease, publicity and education of popular science knowledge should be carried out, and key populations should be monitored to give full play to the role of medical staff and pregnant women and their families.
1. Get rid of bad habits, including pregnant women and their spouses, such as smoking, alcohol and so on.
2. Actively treat diseases affecting fetal development before pregnancy, such as diabetes, lupus erythematosus, anemia, etc.
3. Actively do prenatal checkups to prevent colds. Try to avoid using drugs that have been proven to have teratogenic effects and avoid contact with toxic and harmful substances.
4. For elderly women, family history of congenital heart disease, and serious illness or defects in couples, it should be monitored.
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