Complete pulmonary venous return

Introduction to complete pulmonary venous return Complete pulmonary venous return refers to the venous system that does not enter the left atrium but enters the right atrium or systemic circulation. It often coexists with atrial septal defect. The incidence rate accounts for 1.5 to 2% of congenital heart disease. basic knowledge The proportion of the disease: 0.0001% - 0.0005% (1.5 to 2% in congenital heart disease) Susceptible people: no special people Mode of infection: non-infectious Complications: pulmonary edema, pulmonary hypertension, arrhythmia, malnutrition

Complete pulmonary venous return

The origin of the lung is derived from the foregut. The pulmonary vascular plexus is derived from the visceral venous plexus and flows into the main vein, the umbilical vein and the yolk vein. When the atrium is not separated, the common pulmonary vein protrudes from the middle of the posterior wall of the atrium into two branches, each of which C1 is divided into two, respectively, into the left and right lungs, the venous post-expanded common pulmonary vein is absorbed into the enlarged left atrium, so the four pulmonary veins are all open in the left atrium, and are separated from the systemic veins, and the lungs appear. The junction of the common vein and the left atrium is not developed, but is connected to the main vein, umbilical vein or yolk vein, causing various types of pulmonary malformation connections, the most common being the inflow into the innominate vein or the coronary sinus.

pathology

According to the connection site of pulmonary vein malformation, Darling divides complete pulmonary venous venous return into four types: 1 cardiac type accounts for 55%. The pulmonary veins merge in the posterior left atrium and then drain through the vertical vein to the left innominate vein, sometimes into the superior vena cava or odd. Venous, vertical veins enter the innominate vein in front of the left pulmonary artery and the left common bronchus, where compression can cause venous return obstruction; 2 intracardiac type accounts for 30%, all pulmonary veins are directly introduced into the right atrium or drained through the pulmonary vein to the coronary Intravenous sinus, obstruction may occur between the total trunk of the pulmonary vein and the coronary sinus; 3 subcardiac type accounts for 12%, all pulmonary veins meet at the back of the heart and then pass through the vertical vein to pass through the diaphragmatic esophageal hiatus into the portal vein, inferior vena cava or venous catheter. The returning blood passes through the high-resistance hepatic vascular bed to reach the right atrium or the vertical vein, which can cause pulmonary venous obstruction; 4 mixed type accounts for 3%, all pulmonary veins enter the right atrium through various channels, subcardiac type and mixed type Most of them die in infants and young children. About 75% of patients with complete pulmonary venous return have patent foramen ovale, 25% have In the atrial septal defect, the right atrium, the right ventricle often enlarges hypertrophy, the pulmonary artery enlarges, the pressure increases, the left atrium is smaller, and the pulmonary vein obstruction is most common in the sub-cardiac type, which is second to the heart type, and its incidence can be as high as 50%, and other coexisting Cardiac vascular malformations include patent ductus arteriosus, aortic coarctation, permanent arterial trunk, aortic dislocation, single ventricle, pulmonary atresia, tetralogy of Fallot and double outlet of right ventricle.

Pathophysiology

In patients with complete anomalous pulmonary venous drainage, all pulmonary vein blood enters the right atrium, and the blood in the right atrium needs to flow into the left atrium through the patent foramen ovale or atrial septal defect. Otherwise, it is very dead after birth, and the right atrium receives the pulmonary circulation. All of the blood flow to the heart, the blood flow is extremely increased, and the patient with the patent foramen ovale has a small passage between the atrium, and the blood from the vena cava and the pulmonary vein is mixed into the left atrium and then into the left atrium. Systemic circulation, so there is mild purpura in the clinic, but the blood flow in the right heart chamber and pulmonary circulation is large, and the pulmonary artery pressure is increased. Most of them die from right heart failure within a few months after birth. The atrial septal defect is large, and the left atrium enters the left. The blood flow in the atria is more, the purpura is obvious, and the pulmonary circulation hypertension is delayed. Most patients can survive for more than 1 year. Those with pulmonary venous reflux obstruction have severe purpura, pulmonary vascular stagnation and pulmonary edema, and most of them die several weeks after birth.

Complete pulmonary venous return prevention

90% of patients with complete pulmonary venous return have died within 1 year after birth. Immediately after the diagnosis of pulmonary venous obstruction is confirmed, surgical treatment is needed immediately. Patients with pulmonary vein obstruction are treated with internal medicine and with a balloon catheter to enlarge the atrial septal channel to make congestive If heart failure is controlled, the radical surgery can be suspended for a short time.

Complete pulmonary venous return complications Complications pulmonary edema pulmonary hypertension arrhythmia malnutrition

Complete anomalous pulmonary venous drainage is a rare type of cyanotic congenital heart disease. If not treated, 75% of the children die within 1 year after birth, but the prevention and treatment of postoperative complications is to improve the success rate of surgery. One of the keys, the postoperative complications that are easily complicated by the disease include the following:

1, pulmonary edema

Pulmonary edema may be caused by left heart failure, small left heart development, excessive fluid in the body, too small anastomotic stoma, effects of extracorporeal circulation and pulmonary venous obstruction. The size of the anastomosis is an important factor affecting postoperative outcome. It is 1~4cm, 4~6cm for older children and adults. Once the clinical postoperative children have pink bloody sputum, the oxygenation index decreases, and the bedside chest radiograph shows the increase of double lung density, it indicates the presence of pulmonary edema. .

2, pulmonary hypertension

Postoperative pulmonary hypertension often has different degrees of clinical manifestations, which can be manifested as hepatomegaly, decreased urine output, cold limbs, increased heart rate, simultaneous increase in pulmonary arterial pressure and systemic circulation pressure; once pulmonary artery pressure exceeds systemic circulation pressure, then systemic circulation pressure Decline, that is, the occurrence of pulmonary hypertension crisis, therefore, measures should be taken as soon as possible to prevent, when the child supports the ventilator, especially within 48 hours after surgery, the suction should be carried out under full muscle relaxation and sedation, the action must be Gentle, try to reduce irritation, blood gas should be maintained in a proper hyperventilation state (PCO2 25~35mmHg), prevent hypoxia, timely correct acidosis, and reduce pulmonary arterial pressure drugs with tolazoline, alprostadil and so on.

3, arrhythmia

There may be many types of arrhythmia in children after operation. The possible causes are improper operation, myocardial edema, acid-base imbalance and electrolyte imbalance. Incorrect operation in the atrium can cause arrhythmia with heart rate slowing as the main manifestation. Therefore, the cardiac pacing lead should be placed routinely during the operation, and the arrhythmia with slow heart rate can be temporarily pacing.

4, low cardiac output (low cardiac output syndrome)

Possible causes of low cardiac output after operation are poor intraoperative myocardial protection, myocardial ischemia-reperfusion injury, small left heart development and excessive cardiac load. When blood pressure is low or unstable, peripheral circulation is poor and urine output Should reduce the appearance of low cardiac output when reducing the performance, should promptly strengthen the support of cardiac function, such as routine use of dopamine and dobutamine, low-dose adrenaline or milrinone for children with poor cardiac function; appropriate control The amount of fluid, according to central venous pressure and left atrial pressure to replenish, if necessary, strengthen diuretic to reduce cardiac load; use polarized fluid and 1,6-diphosphate fructose to protect the heart muscle and improve myocardial metabolism.

5, lung infection

The main cause of postoperative pulmonary infection is related to long-term ventilator support, malnutrition and low resistance. Therefore, after the postoperative care function is stable, the ventilator should be evacuated as soon as possible, and nutritional support should be strengthened to prevent lung infection. important.

Symptoms of complete anomalous pulmonary venous reflux Common symptoms Intravenous persistent blood flow, shortness of breath, rapid growth, systolic murmur, pulsating, pulsating, purpura (toe), cardiac malformation, right heart failure

In patients with complete pulmonary venous return, the pulmonary circulation pressure was significantly increased. All patients, regardless of age, showed obstructive pathological changes in the pulmonary arterioles.

The patient's symptoms depend on the presence or absence of obstruction of the pulmonary veins, the size of the heart chamber and other co-existing cardiac malformations. Pulmonary hypertension and right heart failure occur early in the heart chamber. The symptoms develop rapidly and the disease is severe. The lungs are not obstructed. Larger pulmonary hypertension occurs later, but cyanosis is obvious, the disease develops slowly, the baby grows slowly, the breathing is short, the heart beats and the mild cyanosis, and is misdiagnosed as pneumonia and respiratory distress syndrome, the physical examination can be no specific noise, sometimes In the second intercostal space of the left sternal border, there is a squeezing hair-like jet-type murmur. The second sinus of the pulmonary valve has a split and hyperthyroidism. The left lower edge of the sternum may hear a diastolic rumbling noise, and the heart sound zone is enlarged. Lifting pulsation, the clubbing (toe) is generally lighter.

Complete pulmonary venous return

(1) X-ray films showed increased pulmonary vascular shadow, total pulmonary stenosis, right ventricle, right atrium enlargement, and malformation into the left superior vena cava. The upper mediastinum shadow was widened and the entire heart shadow was "8" shaped.

(2) Electrocardiogram examination showed that the electric axis was right-biased, the right ventricle and right atrium were hypertrophy, and sometimes there was incomplete right bundle branch block.

(3) Right heart catheter and selective pulmonary angiography showed that the blood oxygen content of the pulmonary venous blood into the venous blood increased, the peripheral arterial blood oxygen content decreased, the right atrial pressure increased or normal, and the cardiac chamber channel was smaller. The atrial pressure gradient is higher than that of the left atrium. Patients with pulmonary venous obstruction have a significantly increased right ventricular and pulmonary artery pressure. The pulmonary capillary pressure is higher than the left atrial mean pressure. Selective pulmonary angiography can show the abnormal pulmonary veins and abnormal reflux. Pulmonary vein obstruction and combined cardiac vascular malformations.

(4) Cut-to-face echocardiography and Doppler examination can be found that the left atrium does not show pulmonary venous ostium, the right ventricular diastolic volume is overloaded, and the echo of the interatrial septum is interrupted. It can also show abnormal pulmonary vein trunk and combined cardiac vascular malformation. The Pulot examination can show abnormally connected blood flow and right atrium to left atrial shunt.

Diagnosis and diagnosis of complete pulmonary venous return

The diagnosis of this disease is clear, and it needs to be differentiated from other congenital heart diseases when necessary. The most important clinical diagnosis is the diagnosis of atrial septal defect. The reason why this disease is easily misdiagnosed as atrial septal defect is as follows:

1. Complete anomalous pulmonary venous return is very rare, which is easy for clinicians to consider. It is reported that this is not enough for heart surgeons to know about some abnormal signs (such as cyanosis after activity, widening of heart shadow in upper mediastinum, etc.). It is also related to the lack of experience of physicians.

2. There are similarities between the two diseases in the symptoms and signs, especially in the case of atrial septal defect with small opening and obvious cyanosis. X-ray examination has no typical "8" shaped heart shadow, and the inexperienced clinician is easy. Misdiagnosis, ultrasound should be reviewed at this time to prevent misdiagnosis.

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