What is Patent Ductus Arteriosus?

The arterial catheter was originally a normal blood flow channel between the pulmonary artery and the aorta during the fetal period. Due to the pulmonary respiratory dysfunction at this time, the pulmonary artery blood from the right ventricle entered the descending aorta through the catheter, and the blood from the left ventricle entered the ascending aorta. Arterial catheters are necessary for special circulation during the embryonic period. After birth, the lungs swell and assume the function of gas exchange. Pulmonary circulation and systemic circulation perform their respective functions. Soon, the catheter is closed due to disuse. If the artery duct is not closed continuously. Surgery should be performed to interrupt blood flow. Arterial duct patency is a more common type of congenital cardiovascular malformation, accounting for 12% to 15% of the total number of congenital heart diseases, and it is about twice that of women. About 10% of cases coexist with other cardiovascular malformations.

Basic Information

English name: patent ductus arteriosus
Visiting department: cardiology
Multiple groups: female

Common causes: Related to heredity, pregnant women with rubella, influenza, mumps, etc.
Common symptoms: Repeated upper respiratory infections, palpitations, shortness of breath, and fatigue after exertion
Contagious: no

Etiology of Arterial Catheter

Heredity is the main internal cause. Any factors that affect the development of the heart and embryo during the fetal period may cause cardiac malformations, such as rubella, influenza, mumps, coxsackie virus infection, diabetes, hypercalcemia, etc. in pregnant mothers, pregnant mothers exposed to radiation; pregnant mothers Take anticancer drugs or metinine.

Clinical manifestations of open arterial duct

The clinical manifestations of arterial duct occlusion are mainly determined by the amount of shunting blood from the aorta to the pulmonary artery, and whether secondary pulmonary hypertension and its degree are produced. Those with mild symptoms may have no obvious symptoms, and those with severe symptoms may develop heart failure. Common symptoms include palpitations, shortness of breath, and fatigue after exertion, susceptibility to respiratory infections and growth retardation. Pulmonary arterial hypertension is severe in the late stage, and cyanosis of the lower body may occur when a reverse shunt occurs. When the arterial catheter is not closed, a typical sign is a loud continuous machine-like noise heard in the second intercostal space of the left margin of the sternum, accompanied by tremors. The second tone of the pulmonary valve is hyperactive, but it is often obscured by loud noises. Diastolic murmur due to relative mitral stenosis can still be heard in the apical region in patients with larger shunts. The blood pressure measurement showed that the systolic blood pressure was mostly in the normal range, while the diastolic blood pressure was reduced, so the pulse pressure was widened, and the blood vessels in the limbs had water flushing pulses and gunshots.

Infants and toddlers can only hear systolic murmurs. When pulmonary hypertension occurs in the late stage, the murmur has a large variation, which can be only the systolic murmur, or the systolic murmur also disappears and is replaced by the diastolic murmur with pulmonary valve insufficiency.

Arterial duct open examination

ECG examination

There is no obvious abnormal change in mild cases, and the typical manifestations are left axis deviation, high left ventricular voltage or left ventricular hypertrophy. Those with obvious pulmonary hypertension showed enlarged left and right ventricles. In the later stage, right ventricular hypertrophy is predominant, with myocardial damage.

2. Chest X-ray examination

The heart shadow increases, and the left ventricle increases in the early stage, and the right ventricle also increases in the late stage. The ascending aorta and aortic arch shadows widened and the pulmonary artery segment protruded. Pulmonary artery branches thickened, and the pulmonary field was congested. Sometimes the hilar "dance" sign can be seen under perspective.

3. Echocardiography

The left atrium and left ventricle are enlarged, and the pulmonary artery is widened; if pulmonary hypertension is present, the right ventricle can also be enlarged, and abnormal duct traffic can be seen between the aorta and the pulmonary artery bifurcation; color Doppler shows the descending aorta to the pulmonary artery High-speed dual-phase shunting; continuous Doppler can measure the dual-phase continuous high-speed blood flow spectrum.

4. Ascending aortic angiography

Continuous left radiographs showed that the ascending aorta and aortic arch were widened, and the inner edge of the isthmus protruded. The contrast agent flowed into the pulmonary artery through this, and showed the shape, inner diameter and length of the catheter.

5. Right heart catheterization or retrograde aortic angiography

For those who have not been diagnosed after the above examinations, right heart catheterization or retrograde aortic angiography can be used. The former can show that the pulmonary oxygen content is higher than the right ventricle by more than 0.5% of the volume. At the same time, the pulmonary artery pressure and resistance can be measured. If intubated through the arterial catheter into the descending aorta, retrograde aortic angiography can be confirmed. The condition of entering the pulmonary artery.

Differential diagnosis of open arterial duct

There are many intracardiac malformations that diverge from left to right. The same continuous machine-like murmur or nearly continuous biphasic murmur can be heard at the left edge of the sternum, which is difficult to identify. Identification must be made before establishing an arterial duct open diagnosis for treatment:

High ventricular septal defect with aortic valve prolapse

When the high ventricular septal defect is large, it is often accompanied by aortic valve prolapse deformity, which results in aortic valve insufficiency and causes corresponding signs. Clinically, a biphasic murmur is heard at the left margin of the sternum. The diastole is water-spraying and does not conduct upward, but it is sometimes similar to a continuous murmur and difficult to distinguish. At present, color echocardiography has been included in the routine examination of heart disease. This disease can show aortic valve prolapse deformity and aortic blood flow back into the left ventricle, while at the same time through the ventricular septal defect from the left ventricle to the right ventricle and pulmonary artery shunt. To further confirm the diagnosis, retrograde ascending aorta and left ventricle angiography can be performed. The former can show the reverse flow of ascending aorta into the left ventricle, while the latter shows that the left ventricle contrast agent flows into the right ventricle and pulmonary artery through the ventricular septal defect. Based on this, it is not difficult to make a differential diagnosis.

2. Rupture of aortic sinus tumor

This disease is not uncommon in our country. The clinical manifestations of congenital arterial duct patency are similar to those of arterial duct patency. Continuous cardiac murmurs of the same nature can be heard, but the location and conduction direction are slightly different. Those who broke into the right ventricle were lowered to the outside and conducted to the apex; those who broke into the right atrium were transmitted to the right. Such as color Doppler echocardiography showing aortic sinus deformity and its shunt to the ventricular and pulmonary or atrial cavity can be identified, coupled with retrograde ascending aorta angiography can establish a diagnosis.

3. Coronary artery fistula

This kind of coronary artery malformation is rare. You can hear the same continuous murmur with tremor as the arterial duct is not closed, but the location is low and it is biased to the inside. Doppler ultrasound can show the atrioventricular cavity in which the arterial fistula is located. Retrograde ascending aorta angiography is more able to show enlarged lesions of the main branch of the coronary arteries, or branch branches and fistulas.

4. Coronary artery opening

The right coronary artery originates from the pulmonary artery and is a relatively rare congenital heart disease. The heart murmur is also continuous, but lighter and superficial. Doppler ultrasound can help with differential diagnosis. Continuous imaging of retrograde ascending aorta angiography shows abnormal opening and direction of coronary arteries and collateral circulation of tortuous varices, which can be clearly diagnosed.

Arterial duct patency treatment

After the diagnosis of arterial catheter is established, if there is no contraindication, surgery should be selected to interrupt the blood flow at the catheter. At present, most patients with open arterial catheters can be cured by transcatheter catheterization (blocked with Amplatzer mushroom umbrella or coil). For too large or premature arterial ducts can be considered open thoracotomy.

In recent years, premature infants with respiratory distress syndrome due to arterial duct occlusion can be treated first with pro-catheter closure drugs. If the effect is not good, surgical treatment can be advocated.

Arterial catheter closure surgery is generally appropriate before school age. If the partial flow is large and the symptoms are severe, surgery should be performed early. After being too old and having pulmonary hypertension, the risk of surgery increases and the effect is poor. Surgery should be postponed when suffering from bacterial endometritis; however, if the drug does not control the infection well, surgery should still be pursued, and the drug treatment should be continued after the operation, and the infection is often quickly controlled.

Arterial duct complication

There may be complications such as major hemorrhage during operation, left recurrent laryngeal nerve palsy, catheter recanalization, pseudoaneurysm, and chylothorax.

Prognosis of arterial duct

The surgical mortality caused by major bleeding during arterial catheter closure depends on the texture of the catheter wall, the surgical method using the closed catheter, and the skill of the operator, and should generally be within 1%. Recanalization of the catheter is possible after simple catheter ligation or clamping. The recanalization rate is generally above 1%, and the recanalization rate after padding is lower than the previous two. The long-term effect of arterial catheter closure depends on whether there are secondary pulmonary vascular lesions and their extent before surgery. Patients who have undergone surgery before pulmonary vascular disease has fully recovered and live as normal. Pulmonary vascular disease is severely irreversible. Pulmonary vascular resistance is still high after operation, and the right heart load is still heavy. The effect is poor.