How is patent ductus arteriosus diagnosed?

How to diagnose patent ductus arteriosus? Patent ductus arteriosus is a pathological condition in which the ductus arteriosus does not close after birth and remains open. There are more female patients than male patients, but most people do not know much about this disease and do not know how to diagnose it. Therefore, it is necessary to understand the diagnostic method in order to better treat it. Let's learn how to diagnose patent ductus arteriosus!

1. X-ray examination

X-ray examinations of children with small shunts may show no abnormalities. For children with large shunts, X-rays show an enlarged heart, mainly with enlargement of the left ventricle, with the heart shadow expanding to the left and downward, and sometimes the atrium may also be enlarged, the pulmonary artery segment is prominent, the shadow of the hilar blood vessels is thickened, the lung field is congested, and pulsation can be seen under fluoroscopy. The ascending aorta is dilated, and the aortic knot shows a "funnel" sign. If accompanied by severe pulmonary hypertension, the right ventricle is also enlarged, the pulmonary artery segment is prominent, and the surrounding blood vessel shadows become thinner. At this time, the congestion of the lung field is not obvious.

2. Electrocardiogram

The ECG of a patient with a small patent ductus arteriosus can be completely normal. For patients with a small amount of left-to-right shunt, the ECG is basically unchanged. ECG changes depend on the degree and duration of the increase in left ventricular load and the increase in cardiac pressure load. ECG changes can often reflect changes in pulmonary artery pressure. When the pulmonary artery pressure increases slightly, the ECG shows left ventricular hypertrophy; when the pulmonary artery pressure increases moderately, it often shows left and right ventricular hypertrophy; when the pulmonary artery pressure increases severely or reverse shunt occurs, it shows significant right ventricular hypertrophy.

3. Echocardiography

Two-dimensional echocardiography can directly show the enlargement of the left ventricle and left atrium, the increase in the anterior-posterior diameter of the aorta, and the increase in the activity amplitude of the left ventricular posterior bifurcation and the interventricular septum. When the pulmonary artery pressure increases, the right atrial wall thickens. The short-axis section at the bottom of the heart can also directly show the patent ductus arteriosus between the main pulmonary artery and the descending aorta, and its length and diameter can be measured. In the short-axis section of the parasternal aorta of the child, a red or colorful mosaic jet can be observed from the descending aorta through the patent ductus arteriosus into the main pulmonary artery. The shunt volume and pulmonary artery pressure can be measured according to the shunt beam area.

4. Cardiac catheterization and selective angiography

Cardiac catheter examination is not necessary for general cases. If the clinical murmur is atypical or other malformations are suspected, a right cardiac catheter examination should be performed. Right cardiac catheter examination shows that the blood oxygen saturation or blood oxygen content at the pulmonary artery level is higher than that of the right ventricle. When the difference in blood oxygen content between the two exceeds 0.5 volume/cm2, it indicates that there is a left-to-right shunt at the pulmonary artery level. The greater the difference in blood oxygen content, the greater the shunt volume, and the shunt volume can be calculated. If the cardiac catheter enters the descending aorta to the level of the diaphragm through an unclosed catheter, the diagnosis can be more clearly determined.

When pulmonary hypertension occurs, blood oxygen changes are not obvious, or for diseases of left-to-right shunt in different parts, such as main

When it is difficult to differentiate between pulmonary septal defect, ruptured aortic sinus aneurysm, and ventricular septal defect combined with aortic regurgitation, retrograde aortography is required. When contrast agent is injected through the catheter, the ascending aorta and aortic arch are enlarged, the pulmonary artery is visualized at the same time, and the patent ductus arteriosus is visualized to observe the diameter, length, and shape of the ductus.

5. Electrocardiogram

The ECG may be normal in patients with a small shunt, and may show a normal electrical axis, an enlarged left atrium, high left ventricular pressure or left ventricular hypertrophy in patients with a moderate shunt, high Rvs and Rv6 waves, deep Qv5:Qv6, and high, pointed and symmetrical Tvs and TV6. When the shunt is large or the pulmonary artery pressure is high, the electrical axis may be normal or left-deviated, with biventricular hypertrophy, and the R and S waves of V3 and V4 are both tall. When the pulmonary artery pressure is equal to the systemic circulation pressure, the electrical axis may deviate to the right, and the right ventricle may show an increased systolic load.

6. Others

Routine blood and urine tests, complete biochemical test set, prothrombin time and activity, immunological tests for hepatitis B and hepatitis C, and syphilis and AIDS tests.