Patent ductus arteriosus



The arterial catheter is the normal blood flow channel between the pulmonary artery and the aorta during the fetal period. Because of the pulmonary respiratory dysfunction, the pulmonary blood from the right ventricle enters the descending aorta through the catheter, while the blood in the left ventricle enters the ascending aorta. Arterial catheters are required for special circulation in the embryonic period. After birth, the lungs swell and bear the function of gas exchange. The pulmonary circulation and the systemic circulation perform their duties. Soon, the catheter is closed due to waste, and the patent ductus arteriosus is formed if it is not closed. Surgery should be performed to interrupt its blood flow. Patent ductus arteriosus is a more common congenital cardiovascular malformation, accounting for 12% to 15% of the total number of congenital heart diseases.



Genetics is the main internal cause. Any factors affecting the development of heart embryo during the fetal period may cause cardiac malformations, such as pregnant women with rubella, influenza, mumps, Coxsackie virus infection, diabetes, hypercalcemia, etc. The mother is exposed to radiation, and the pregnant mother takes anticancer drugs or drugs such as carnosine.


an examination

1, ECG sub-flow can have different degrees of left ventricular hypertrophy, occasional left atrial hypertrophy, lung buying pressure significantly increased, left and right ventricular hypertrophy, severe cases only see right ventricular hypertrophy.

2, X-ray examination of the arterial catheter fine cardiovascular shadow can be normal. The ratio of heart to chest increased, the left ventricle increased, the apex dilated downward, and the left atrium also increased slightly. Pulmonary blood increased, the pulmonary artery segment was prominent, and the hilar vascular shadow was thickened. When the baby has heart failure, the lungs and blood stasis can be seen, and the left ventricle and aorta beat under the sling. In pulmonary hypertension, the total trunk and branches of the pulmonary artery at the hilar are enlarged and the pulmonary arterioles in the distal lung field are narrow, and the left ventricle has signs of enlarged hypertrophy. The aortic node is normal or bulging.

3, echocardiography is very helpful for diagnosis. Two-dimensional echocardiography can directly detect unclosed arterial catheters, often using the parasternal pulmonary dynamics or the long axis of the upper sternum. Pulsed Doppler can also detect typical systolic and diastolic continuous sputum retention spectra at the opening of the arterial catheter. Superimposed color Doppler visible red flow column from the descending aorta, through the forbidden catheter along the extrapulmonary wall, in the case of severe pulmonary hypertension, when the pulmonary artery pressure exceeds the aorta, visible blue flow from the pulmonary artery through the patent ductus Enter the descending aorta.


Differential diagnosis

There are many left-to-right shunt intracardiac malformations that can be heard on the left sternal border of the same continuous machine-like murmur or near-continuous two-phase heart murmur, which is difficult to identify. It must be identified before the diagnosis of patent ductus arteriosus is established. The main malformations are now discussed as follows.

(1) High ventricular septal defect combined with aortic valve prolapse

When the high ventricular septal defect is large, it is often accompanied by aortic valve prolapse, resulting in aortic regurgitation and corresponding signs. Clinically, two-stage murmurs are heard on the left sternal border. The diastolic phase is water-like and does not conduct upwards, but sometimes it is similar to continuous murmurs and difficult to distinguish. At present, color echocardiography has been routinely examined for heart disease. In this disease, aortic valve prolapse and aortic blood flow back into the left ventricle can be shown, while the ventricular septal defect is diverted from the left ventricle to the right ventricle and pulmonary artery. To further confirm the diagnosis, retrograde ascending aorta and left ventricular angiography can be performed. The former can show that the ascending aorta contrast agent flows back into the left ventricle, while the latter shows that the left ventricular contrast agent diverts the right ventricle and pulmonary artery through the ventricular septal defect. According to this, it is not difficult to make a differential diagnosis.

(two) rupture of aortic sinus

This disease is not uncommon in China. The clinical manifestations are similar to those of patent ductus arteriosus. Continuous heart murmurs of the same nature can be heard, but the location and conduction direction are slightly different. Those who have broken the right ventricle are biased to the apex, and the right atrium is deflected to the right. Side conduction. For example, color Doppler echocardiography shows aortic sinus malformation and its diversion to the ventricular and pulmonary or atrial cavity can be identified

(C) coronary artery fistula

This type of coronary artery malformation is rare and can be heard with the same continuous murmur as the patent ductus arteriosus with tremor, but with a lower part and a medial side. Doppler color ultrasound can show the chamber cavity where the arterial fistula is located and communicates with it. Retrograde ascending aorta angiography is more likely to show enlarged coronary artery main branches, or branching and sputum.

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