What is Tricuspid Atresia?

Tricuspid atresia is a type of congenital heart disease with a incidence of 1% to 5%. Ranked third after traumatic congenital heart disease with Fallot tetralogy and transposition of the aorta. The main pathological changes are tricuspid valve atresia or absence of tricuspid valve, oblong foramen ovale or atrial septal defect, left ventricular enlargement, and right ventricular dysplasia. Under normal development of the embryo, the endocardial cushion is fused, and the atrioventricular tube is divided into two left and right orifices, which participate in forming the ventricular septum of the membrane and closing the first hole of the atrial septum. It is generally believed that the fusion site of the endocardial cushion before and after the embryonic period is biased to the right, the ventricular septum is shifted to the right to cause uneven atrioventricular openings, and the right atrioventricular occlusion will form a tricuspid valve atresia in the future.

Basic Information

English name: Tricuspid Atresia
Visiting department: Cardiology, Cardiac Surgery
Common locations: heart

Common causes: Embryonic abnormalities
Common symptoms: Those with small atrial septal passages have systemic venous congestion, jugular vein irritation, and peripheral edema; cyanosis in newborns, shortness of breath after exertion; fingers (toe) over 2 years old

Causes of tricuspid atresia

Under normal development of the embryo, the endocardial cushion is fused, and the atrioventricular tube is divided into two left and right orifices, which participate in forming the ventricular septum of the membrane and closing the first hole of the atrial septum. It is generally believed that the fusion site of the endocardial cushion before and after the embryonic period is biased to the right, the ventricular septum is shifted to the right to cause uneven atrioventricular openings, and the right atrioventricular occlusion will form a tricuspid valve atresia in the future.

Clinical manifestations of tricuspid atresia

Symptoms

The survival time of patients with tricuspid atresia is closely related to pulmonary blood flow. Those with close to normal pulmonary blood flow can survive for more than 8 years; those with a lot of pulmonary blood flow generally can only survive for 3 months after birth; those with less than normal pulmonary blood flow live in the above two conditions after birth between. In patients with small atrial septal channels, clinically presenting systemic venous congestion, jugular vein distension, hepatomegaly, and peripheral edema. Due to the small amount of blood in the pulmonary circulation, most cases can show cyanosis, shortness of breath after exertion from the neonatal period, and can adopt squatting position or hypoxic syncope. Patients over 2 years old often have clubbing fingers (toes). In patients with increased pulmonary blood flow, cyanosis is reduced, but often shortness of breath, rapid breathing, prone to lung infections, and often congestive heart failure.

2. Signs

The left margin of the sternum can often hear systolic whistle-like murmurs caused by pulmonary valve stenosis or ventricular septal defects, and those with arterial duct occlusion can hear continuous machine-like murmurs. Those with increased pulmonary blood flow can hear roller-like noise during middle diastole. In addition, there may be signs of hepatomegaly, edema, jugular vein distension, and pulmonary edema.

Tricuspid atresia

ECG examination

In 90% of cases, the electrical axis was left-biased, and the aorta was displaced. Pulmonary arterial enlargement is normal or right. Leads in the precardiac area showed left ventricular hypertrophy and T wave inversion. 80% of the cases showed P-wave height or broadening with notches.

2.X-ray inspection

There are many variations in chest X-rays. Heart shadow is normal or slightly enlarged in patients with reduced pulmonary blood flow, and heart shadow is significantly enlarged in patients with increased pulmonary blood flow. Typical chest X-ray signs are a straight right edge of the heart, a blunt left heart edge, an elevated apex, and a depressed heart waist. Heart shadow of aortic transposition can be egg-shaped. In patients with low pulmonary blood flow, the lung texture was significantly reduced, and those with pulmonary congestion showed increased lung texture.

3. Cardiac Catheter and Cardioangiography

The right atrial catheter can enter the left atrium through the atrial defect, and the pressure in the right atrium is higher than that in the left atrium. The pressure difference is inversely proportional to the diameter of the atrial defect. The defect is small and the pressure difference is large. The arterial blood oxygen content was reduced, and the left atrium, left ventricle, pulmonary artery, and aorta were the same.

4. Selective right atrial angiography

It is shown that the contrast agent enters the left atrium, the left ventricle from the right atrium, and then enters the pulmonary and aorta. Below the heart shadow, an undeveloped triangular area, namely the right ventricle window, is located between the right atrium, the left ventricle, and the diaphragm. Sometimes angiography can show ventricular septal defect, right ventricular cavity and outflow tract and pulmonary artery. In addition, the relationship and location of the two aorta can be displayed, and left ventricular angiography can determine whether there is mitral regurgitation.

5.M echocardiogram

It showed that the tricuspid valve bimodal curve disappeared, the tricuspid valve examination failed to see the tricuspid valve leaflet opening and closing activity, the atrial septal echo was interrupted, and the upper ventricular septal echo was interrupted. Echocardiography and Doppler examination revealed blood flow from the right atrium to the left atrium before entering the left ventricle. Mitral valve activity increased, the right atrium, left atrium, and left ventricular cavity all increased, and the right ventricle was small or disappeared.

Diagnosis of tricuspid atresia

Symptoms such as cyanosis, shortness of breath, and fatigue are present clinically, and the electrocardiogram shows the left side of the electrical axis and left ventricular hypertrophy, and the P wave is high and wide. It is highly suspected that there may be tricuspid valve atresia. Right heart catheterization, cardiovascular angiography, and echocardiography can clearly diagnose the disease.

Differential diagnosis of tricuspid atresia

It needs to be distinguished from tetralogy of Fallot, Ebstein's deformity, transposition of aorta, double outlet of right ventricle, and single ventricle.

Tricuspid atresia treatment

The prognosis of tricuspid atresia is poor, and the survival time is very short. About 70% of sick children die within one year after birth. Neonatal cases show severe cyanosis due to reduced pulmonary blood flow. If there is a pressure difference between the right atrium and the left atrium, the following palliative surgery can be performed to increase pulmonary blood flow.

(1) Palliative surgery

Systemic pulmonary circulation shunt

Commonly used is the left subclavian artery-pulmonary end-to-side anastomosis or a Gortex artificial blood vessel connected between the subclavian artery and the pulmonary artery. A descending aorta-left pulmonary artery lateral anastomosis or ascending aorta-common pulmonary artery lateral anastomosis can also be performed. The latter two procedures may result in a twisted pulmonary artery or an excessively large anastomosis of the pulmonary blood flow.

2. Enlarged atrial septal defect with closed catheter or closed partial atrial resection

In the tricuspid atresia, two-thirds of the interventricular interventricular intervertebral space is closed, and 1/3 is the atrial septal defect. Examination of the right atrial catheter revealed that the right atrial pressure was higher than the left atrial pressure> 5 mmHg, and the channel between the atria needed to be enlarged. A balloon catheter could be used to expand the balloon defect through the atrial septal defect. This method can be performed during cardiac catheterization and is often used to reduce symptoms in infants and young children. In addition, a closed method can be used to create a defect in the atrial septum, relieve high blood pressure in the right atrium and vena cava, and relieve right heart failure.

3. Right superior vena cava anastomosis

The surgical effect is good, and its advantages are that it does not increase the left ventricular load and does not produce pulmonary vascular disease. However, the mortality rate of patients under 6 months is relatively high, and the operation is very difficult in the future reconstruction surgery.

4. Pulmonary artery cerclage

Excessive pulmonary blood flow leads to congestive heart failure and is prone to pulmonary vascular obstruction. It is difficult to control heart failure after medical treatment. Pulmonary arterial ligation can be used to reduce pulmonary blood flow, improve heart failure and prevent pulmonary vascular disease.

(Two) corrective surgery

In 1968, Fontan performed right atrial-pulmonary anastomosis and sutured atrial septal defect to treat tricuspid atresia successfully. The goal of the Fontan operation is to introduce all the blood that returns from the systemic circulation into the right atrium into the pulmonary arteries, and perform oxygenation in the lungs without relying on the right ventricle to pump blood. Retain anatomical deformities. Surgical indications are: mean pulmonary arterial pressure <15mmHg; pulmonary vascular resistance m2; left ventricular ejection index> 0.6; left ventricular end-diastolic pressure 2 to 3 years old; iliac sinus rhythm; aortic pulmonary artery diameter ratio 0.75.

Fontan surgery has the following methods:

Right atrium-pulmonary artery junction

It is suitable for tricuspid atresia of large vessel transposition or pulmonary artery stenosis, but the left and right pulmonary arteries develop well. During the operation, the root of the common pulmonary artery was severed, and the proximal end was closed. The common pulmonary artery turned to the right after passing through the aorta and coincided with the top of the right atrium. The common pulmonary artery and left and right pulmonary arteries need to be fully free during the operation to prevent postoperative stretch and cause anastomotic stenosis. When closing the atrial defect with a pericardial patch, separate the top of the left atrium into the right atrium to ensure the diameter of the anastomosis. The diameter of the anastomosis within 2 years of age must not be less than 2cm, and the age of 3 years and older should be 2.5 ~ 3cm. In addition, an extravalvular tube was placed between the right atrium and the pulmonary artery, and the atrial septal defect was closed with a patch through the right atrium incision. Before closing the chest, you must check whether the external catheter is compressed. If it is compressed, you should remove part of the sternum posterior plate.

2. Right atrial-right ventricular outflow tract anastomosis

Suitable for right ventricular outflow tract without stenosis, pulmonary artery annulus and common pulmonary artery without stenosis, or no space between the aorta and superior vena cava. In the surgical method, a -shaped incision is made in the right atrium, the atrial wall is turned to the right ventricular outflow tract incision, and anastomosis is made with the lower edge of the incision. In addition, by placing an external catheter between the right atrium and the right ventricle, a right ventricular incision can be made under extracorporeal circulation, the hypertrophic muscles in the funnel cavity are removed, and the ventricular septal defect is directly sutured or repaired with a patch. The right atrial incision was used to close the atrial septal defect with a patch. Finally, the right atrium and right ventricular funnel were anastomosed with a polyester woven sheet or Gortex outer tube.

3. At present, modified Fontan surgery and total vena cava-pulmonary anastomosis are mostly used.

The development of this type of surgery has made tricuspid atresia surgical treatment good results. Especially in the past 5 years, an extracardiac duct total vena cava-pulmonary anastomosis has been carried out. This operation has no intracardiac operation, no cardiac arrest, or even extracorporeal circulation. The operation is so simplified that it has gradually become the most suitable surgical treatment of tricuspid atresia Technique.

Tricuspid atresia prevention

Tricuspid atresia is a complex cyanotic congenital cardiovascular malformation with a poor prognosis and a short survival time. About 70% of sick children die within one year after birth. At present, there are no effective preventive measures. The main clinical diagnosis is to distinguish from other types of congenital heart disease in diagnosis, in order to timely and correctly treat children.