Cyanotic CHD: Increased Pulmonary Flow

Introduction:

Cyanosis refers to abnormal bluish discolored skin occurring as a result of poor blood flow or insufficient oxygenation in the blood. Infants with systemic cyanosis are the major cases in daily hospitalizations. There are various causes of cyanosis in infants and neonates, including toxic, cardiac, pulmonary, and hematologic causes. Generally, congenital heart defects might result in cyanosis.

The apparent cardiac-related cause of cyanosis can be decreased pulmonary blood flow. Nevertheless, certain congenital heart defects could cause cyanosis with increased pulmonary blood flow. So, physical examination is significant in the suspected cases, as neonates are discharged right after birth. It is essential to remain alert and monitor the infant who has signs of increased pulmonary blood flow, with or without cyanosis.

What Is Cyanotic Congenital Heart Disease?

Cyanosis congenital heart disease (CCHD) is a condition that is typically present at birth. This condition results from significantly low oxygen levels or defective blood circulation. The common characteristic feature of CCHD includes a bluish skin tint known as cyanosis. Certain birth defects can cause this cardiac disease in neonates and infants.

• Defective formation or issue with the heart valves. Valves are the flaps that help the blood flow in the right direction within the heart.

• Any interruption in the aorta, whereas the aorta is known to be the largest artery in the body.

• Any abnormalities or anomalies in the larger blood vessels that lead from or to the heart.

What Are the Symptoms of Cyanotic Congenital Heart Disease?

Cyanosis primarily manifests as a bluish discoloration of the fingers, toes, and lips, resulting from decreased oxygen levels in the blood. Cyanosis can occur either during rest or when the child is active. Certain children experience dyspnea and may adopt a squatting position after physical activity to alleviate shortness of breath. Other symptoms include anxiety, hyperventilation, syncope, chest pain, reduced appetite, puffy face, etc.

How Is Cyanotic Congenital Heart Disease Diagnosed?

Some of the diagnostic modalities include:

• Physical examination.

• Chest X-ray.

• ECG.

• Pulse oximeter.

• Complete blood count, etc.

Is Cyanotic Congenital Heart Disease Associated With Increased Pulmonary Flow?

Infants and neonates born with heart defects (congenital heart defects) have changes in the way and direction of the blood flow through the heart (systemic) and lung (pulmonary). This can either decrease or increase the blood flow within the heart and lungs. Such congenital heart defects could cause cyanosis in neonates and infants. So, The apparent reason in most cases can be attributed to decreased or increased pulmonary blood flow.

How Is Cyanotic Congenital Heart Disease Associated With Increased Pulmonary Flow?

Cyanotic congenital heart disease is not a single condition. A great number of entities generally present as cyanotic congenital heart disease. Such integrities can be divided into two major classes: increased or decreased pulmonary blood flow (vascularity).

The conditions associated with increased pulmonary blood flow or increased pulmonary plethora (an appearance detected in the chest radiograph showing increased pulmonary blood flow) are listed below.

• Total Anomalous Pulmonary Venous Return (TAPVR): TAPVR is a typical cyanotic congenital heart defect where the complete pulmonary venous system has an abnormal drainage framework as an anomaly. This TAPVR differs from partial anomalous pulmonary venous return (PAPVR) in that a partial defect shows an abnormality in only a part of the pulmonary venous framework.

Due to abnormal pulmonary anatomy in TAPVR, all the blood concerning systemic and pulmonary circulation enters the right atrium, but none gets drained into the heart's left atrium. The treatment for total anomalous pulmonary venous return includes a right-to-left shunt for the individual's survival. The right-to-left shunt allows the blood to flow from the right aspect to the left aspect of the heart.

• Transposition of the Greater Arteries: The transposition of the great arteries (TGA) is also called the transposition of great vessels. TGA is known to be the most common cyanotic congenital heart anomaly seen in newborns. Cyanosis, in this case, is usually detected in the first 24 hours after birth or the first 24 hours of life. It occurs due to a change or transposition in the greater blood vessels of the heart. Ventriculoarterial discordance (disharmony) is the primary concern in this case. So, here, the aorta arises from the right ventricles, while the pulmonary trunk is from the left ventricle. This can be further divided into two subtypes according to the positional relationship between the aortic and pulmonary valves.

• Large Atrioventricular Septal Defect: An atrioventricular septal defect is also referred to as an atrioventricular canal defect and an endocardial cushion defect. This can represent about two to seven percent of the total congenital heart defects. Atrioventricular septal defects (AVSDs) include various cyanotic congenital defects involving the ventricular septum, atrial septum, and either one or both valves (mitral or tricuspid valve). AVSD results when there is a deficient development in the anatomy of the apex portion of the atrial septum, the basal part of the ventricular septum, and the atrioventricular valves. Here, there will be communication between the chambers of the heart. Both right-to-left shunts and left-to-right shunts could happen.

• Truncus Arteriosus: A less common cyanotic congenital heart defect accounting for up to two percent of the cases. This defect is generally categorized as conotruncal cardiac anomalies, whereas conotruncal anomalies refer to defects with the significant involvement of great vessels and outflow trunks. Here, a single trunk is known to supply both the pulmonary and systemic circulation rather than separate pulmonary and aorta trunks. Truncus arteriosus mostly occurs associated with ventricular septal defect (VSD) for making allowances for blood flow circuit completion.

• Single Ventricle With the Absence of Pulmonary Stenosis: A single ventricle without pulmonary stenosis can represent cyanotic congenital heart disease with increased pulmonary blood flow in most cases. Pulmonary valve stenosis is a kind of valvular cardiac disease characterized by the narrowing of the pulmonary valve opening within the right ventricle and pulmonary trunk.

Conclusion:

The common cyanosis congenital heart defect could increase pulmonary blood flow. The lesions associated with the increased pulmonary blood flow include total anomalous pulmonary venous connection, single ventricle, tricuspid atresia, truncus arteriosus, and transposition of the greater arteries. Increased pulmonary blood flow complications and their associated underlying causes are examined. With new advances in hemodynamics, diagnosis, and treatment strategies, corrective procedures can be done at any age for congenital heart diseases. The intervention includes both medical and surgical management of the lesson presented.