Why doesn't the duct close?
The closure of the duct begins after birth: the oxygen content in the blood increases, the level of prostaglandins decreases, and the muscle wall of the vessel contracts. In premature babies, these mechanisms are immature, so the duct remains open much more often. In full-term infants, the preservation of the duct is usually associated with the structural features of its wall. A separate situation is heart defects, in which the duct is vital, and, on the contrary, it is specially kept open before surgery.
- Prematurity and low birth weight
- Respiratory disorders and hypoxia in the first days
- Rubella and other infections in the first trimester
- Childbirth at high altitudes
- Genetic syndromes and familial predisposition
How it manifests itself
The clinic depends on the diameter of the duct. The narrow duct often does not reveal itself in any way, except for the characteristic continuous noise that the doctor hears under the left collarbone. A wide duct causes excessive blood flow to the lungs: shortness of breath, tachycardia, sweating, difficulty feeding, and weight loss. In premature infants, a large duct aggravates respiratory problems and prolongs the need for respiratory support. In adolescents and adults, untreated ductus causes shortness of breath and fatigue.
- Continuous systole-diastolic murmur
- Rapid breathing and heart rate
- Sweating and fatigue when feeding
- Low weight gain
- Frequent respiratory tract infections
- High pulse pressure, “jumping” pulse
What are the dangers of an untreated duct?
The constant discharge of blood from the aorta into the pulmonary artery overloads the blood vessels of the lungs. Over time, irreversible changes develop in them and pulmonary hypertension is formed: when the pressure in the small circle exceeds the systemic one, the direction of discharge changes, the lower half of the body appears blue, and the closure of the duct becomes dangerous. A patent duct also increases the risk of infective endocarditis. That is why a significant duct is closed in advance.
- Left heart overload
- Pulmonary hypertension
- Heart failure
- Infective endocarditis
- In premature infants, worsening of lung and intestinal diseases
Diagnostics
The main method is echocardiography with Doppler study: it shows the duct itself, its diameter, direction and speed of flow, overload of the heart chambers and indirect signs of pressure in the pulmonary artery. An ECG and chest x-ray complete the picture. In premature infants, echocardiography is performed directly in the department and repeated over time, assessing the hemodynamic significance of the duct. Angiography is performed before endovascular closure.
- EchoCG with Doppler, in infants - EchoCG of newborns
- ECG with interpretation
- X-ray of the chest organs
- Pulse oximetry on the arm and leg
- Angiography before intervention
Treatment
In premature babies with a significant duct, the doctor may prescribe drugs that suppress the synthesis of prostaglandins - they help the duct close. In full-term infants and adults, medications are ineffective and the duct is closed mechanically. Today, this is most often done endovascularly: a catheter is passed through the femoral vessel and a spiral or occluder is installed, without an incision in the chest. Surgical clipping or ligation is used in small premature infants and unsuitable anatomy. A small asymptomatic duct may be observed.
- Observation of small duct without cardiac overload
- Medical closure in premature infants as prescribed by a neonatologist
- Endovascular occlusion with a coil or occluder
- Surgical ligation or clipping of the duct
- Control echocardiography after closure
- Oral hygiene and endocarditis prevention