What is the method commonly used to check for patent ductus arteriosus?

What are the commonly used methods to check for patent ductus arteriosus? Patent ductus arteriosus brings particularly serious harm. Many babies are harmed by this disease, which will also affect the growth of the children. Therefore, this disease must be checked and treated early. What are the commonly used methods to check for patent ductus arteriosus?

(I) X-ray examination shows pulmonary congestion, thickened and strong pulsation of the pulmonary artery shadow, bulging of the pulmonary artery main trunk arc, obvious aortic arch shadow, and enlarged left ventricle in patients with large shunt volume. Nearly half of the patients can see a local funnel-shaped bulge of the aorta at the attachment of the ductus arteriosus, which is called the funnel sign. It is manifested in the frontal film as the shadow below the aortic knot does not retract, but continues to bulge to the left and then moves inward in an oblique wave shape to the shadow of the descending aorta. In the left anterior oblique film, the aorta suddenly contracts inward at the beginning of the descending aorta. Occasionally, in the left lateral film, a small piece of calcified shadow of the patent ductus arteriosus can be seen near the lower end of the aortic arch.

(B) Electrocardiogram examination may show four types of changes: normal, left ventricular hypertrophy, combined hypertrophy of both left and right ventricles, and right ventricular hypertrophy. The latter two are accompanied by corresponding degrees of pulmonary hypertension.

(III) Echocardiography can show an increase in the left ventricular internal diameter and an increase in the amplitude and velocity of mitral valve activity. Two-dimensional echocardiography may show a patent ductus arteriosus. Color Doppler blood flow imaging can detect blood flow from the descending aorta through the patent ductus arteriosus into the pulmonary artery.

(IV) Cardiac catheter examination and selective indicator dilution curve measurement The main finding of right cardiac catheter examination is that the oxygen content of pulmonary artery blood is more than 0.5% higher than that of right ventricle blood, pulmonary blood flow increases, pulmonary artery and right ventricular pressure may be normal or slightly increased, and the cardiac catheter may enter the descending aorta from the pulmonary artery through the patent ductus arteriosus. Those with significantly increased pulmonary artery pressure may have bidirectional or right-to-left shunts, at which time the arterial blood oxygen content, especially the lower limb artery blood oxygen content, is reduced. In patients with a small patent ductus arteriosus and a small left-to-right shunt, a cardiac catheter with a platinum electrode can be placed in various parts of the right heart and pulmonary artery. The patient inhales hydrogen to perform a hydrogen dilution curve measurement to find that the horizontal curve at the pulmonary artery arrives ahead of time, and the arrival time is less than 4 seconds.

(V) Selective cardiovascular angiography Selective aortography shows that the aortic arch is visualized while the pulmonary artery is also visualized. Sometimes, the patent ductus arteriosus and the local funnel-shaped bulge of the aorta at the attachment of the ductus arteriosus can also be seen. Sometimes, the proximal ascending aorta and aortic arch are dilated while the distal aorta is smaller in diameter. The ductus arteriosus connects the pulmonary artery trunk (or left pulmonary artery) and the descending aorta, and is located below the opening of the left subclavian artery. The lungs do not have respiratory function during the fetal period, so most of the blood does not enter the lungs, but is transferred from the pulmonary artery to the aorta through the ductus arteriosus.

After birth, as the lungs develop respiratory function and the pulmonary blood vessels expand, the ductus arteriosus loses its function and gradually closes. 95% of infants close within one year after birth (80% of infants close within the third month after birth). If it is still not closed at this time, it is called patent ductus arteriosus. There are three types of patent ductus arteriosus: tubular, window, and funnel. The length ranges from 2 to 30 mm and the diameter ranges from 5 to 10 mm. The window type has almost no length, and the funnel type has a narrower pulmonary artery end. This disease can coexist with other congenital heart and vascular diseases, the most common of which are aortic coarctation, great vessel transposition, pulmonary artery stenosis, atrial septal or ventricular septal defect, etc.

The above content introduces the examination methods of patent ductus arteriosus. This disease has many causes and will cause serious harm to the baby's health after the onset of the disease. Parents must have an in-depth understanding of patent ductus arteriosus and pay attention to the examination of this disease.