Patent Ductus Arteriosus – Symptoms, Diagnosis And Treatment
Persistence from fetal life of the communication between the pulmonary artery and descendant aorta is called patent ductus arteriosus. Prevalence is higher in immature newborns, about 20%, of whom 12% are hemodynamically unstable. The incidence is 1 to 2500 -5000 of newborns to term. The ductus arteriousus is located between the left pulmonary artery and descendant aorta, distal to the origin of left subclavian artery.
Pathophysiology of patent ductus arteriosus:
At birth, the ductus arteriosus functionally closes under the action of oxygenated blood, of the decrease level of prostaglandin E2, leading to its constriction and then will appear the anatomical closure by fibrosis. Patent ductus arteriosus, depending on the size, cause a left-right shunt from the aorta to the pulmonary artery, which is leading to a volume and pressure overloading of the pulmonary circulation. Patent ductus arteriosus is a unique structure whose presence can lead to severe cardiac decompensation, but in other situations (transposition of great arteries without left-right shunt) may be saving and should be maintained until the disease is resolved by surgery. Patent ductus arteriosus in premature infants, where development is incomplete must be destinguished from infants at term with patent ductus arteriosus, which is a congenital cardiac malformation.
Symptoms of patent ductus arteriosus:
Symptoms of patent dustus arteriosus are variable, from asymptomatic state to cardiovascular shock and death. The magnitude of symptoms depends on the size of ductus arteriosus and peripheral pulmonary vascular resistances. The clinical examination may reveal a trill on auscultation, a systolic-diastolic murmur, wide apexian shock, tachycardia, hypotension. Large patent ductus arteriosus gives a murmur that sounds slowly or is absent. The left atrium and left ventricle are dilated due to increased volume of blood which is returning from the lungs. The result of this left-right shunt, is the appearance of pulmonary and systemic signs: manifestations of heart failure, tachycardia, gallop rhythm, pulmonary edema and hepatomegaly. By decreasing of the aortic blood flow, distal from ductus arteriosus, abdominal organs perfusion will be inadequate and will appear oliguria, ileus and acidosis.
Diagnosis of patent ductus arteriosus:
A high degree of suspicion must exist in premature infants with cardio-circulatory imbalance immediately after birth.
- ECG – shows signs of the left ventricle and left atrium overloading, right ventricular hypertrophy occurs later with the increasing of pulmonary vascular resistance.
- Chest radiography – In large patent ductus arteriosus, radiography is showing signs of pulmonary overloading, signs of pulmonary edema and cardiomegaly due to left atrial and left ventricle dilatation.
- Echocardiography – Doppler color method is showing the shunt between the large vessels and its direction. With this exploration can be examined the heart cavities left ventricle, left atrium and cardiac valvular function. Echo can exclude associated anomalies like, ventricular septal defect, interatrial septal defect, Ebstein disease.
- Cardiac catheterization – is used more as a treatment method than as a diagnose method. Is indicated when are suspected other injuries or when pulmonary hypertension is problematic.
Natural evolution of patent ductus arteriosus:
Eisenmenger syndrome may be the final stage of a untreated patent ductus arteriosus, which evolves into irreversible pulmonary vascular disease. In this case heart-lung transplantation remains the only therapeutic solution.
Treatment of patent ductus arteriosus:
Once the diagnosis of patent ductus arterosus is suspected or confirmed, the treatment should be established. Thus, exist medical and surgical methods of treatment. Planning an intervention or other type of treatment is controversial, generally remaining three indicative directions: symptomatic patent ductus arteriosus must be treated, presymptomatic treatment and prophylactic treatment.
Prophylactic treatment – administration of indomethacin in premature newborns showed a success rate of closing the ductus arteriosus in 90% of cases. It is administered 10 mg/kg for 3 days. Echocardiography control can help to establish the success or the failure of the treatment.
Patent ductus arteriosus ligation – is indicated in all cases of symptomatic or asymptomatic patent ductus arteriosus, with left-right shunt that does not close spontaneously after drug theraphy. This treatment is done to avoid cardio-pulmonary decompensation, irreversible vascular pulmonary disease or infection. This can be done surgically or videoscopic.
Interventional treatment – consists in placing a special device at the level of patent ductus arteriosus, thus obtaining a thrombosis in most cases, local inflammatory reaction and closure of the ductus arteriosus. Although, these techniques are less invasive than surgical technique, the success rate is not 100% because there are specific complications (embolization of the device into lungs or into descending aorta).