Dr Arvind Kohli
Cyanotic congenital heart disease (CCHD) is a condition present at birth that results in low levels of oxygen in the blood. The classic symptom of cyanotic congenital heart disease is cyanosis, the bl ue coloring of the skin, which occurs particularly in the lips, toes, and fingers. Another common symptom is difficulty breathing, especially after physical activity. Some children also experience spells during which oxygen levels are very low and they get anxious, exhibit blue skin, and may hyperventilate.
Risk Factors for Cyanotic Congenital Heart Disease
In many cases, an infant will be born with cyanotic heart disease because of a genetic factor. An infant is more at risk when there is a family history of congenital heart diseases. Certain genetic syndromes can be accompanied by defects that cause cyanotic heart disease, such as Down, Turner, Marfan, and Noonan syndromes. In fewer instances, outside factors can cause cyanotic heart disease. Exposure of a pregnant mother to toxic chemicals and illegal drugs may lead to heart defects in the infant. Infections, during pregnancy are also a factor, as is gestational diabetes that is poorly controlled.
Defects that cause cyanotic congenital heart disease
There are many physical defects in the heart that can cause cyanotic congenital heart disease. Some infants may be born with several defects. A few of the defects that are common causes of cyanotic congenital heart disease include:
Tetralogy of Fallot (TOF)
TOF is the most common cause of cyanotic heart disease. It is a actually a combination of four different defects- which is why it is called “tetralogy’’ (four) of Fallot.TOF includes a hole between the right and left ventrices of the heart, a narrow pulmonary valve, a thickening of the right venticle muscles, and a misplaced aortic valve. The defects lead to blood with and without oxygen getting mixed together and pumped throughout the body.
Transposition of the Great Arteries (TGA)
In infants with TGA, the pulmonary and aortic valves and their arteries have switched positions. The result is that low-oxygen blood, which should go to the lungs through the pulmonary artery, gets pumped out to the rest of the body through the aorta.
Tricuspid Atresia
In this type of defect, the tricuspid heart valve has developed abnormally or is missing entirely. This causes disruption to the normal blood flow, resulting in low-oxygen blood being pumped out to the body.
Total Anomalous Pulmonary Venous Connection (TAPVC)
TAPVC occurs when veins that bring high-oxygen blood from the lungs to the heart are connected to the right atrium. They should be connected to the left atrium. This may also be accompanied by a blockage in the vein between the lungs and the heart.
Ebstein anomaly and hypoplastic left heart syndrome
Diagnosis :
Babies developing severe cardiovascular and respiratory distress/collapse require urgent hospital admission, CXR, blood gases, assessment of renal function and electrolytes and assessment of other possible causes of cardiovascular collapse, e.g full infection screen.
Most cyanotic heart defects are identified through the use of an echocardiogram. Sound waves are used to visualize the structures of the heart. The presence of a right to left shunt as seen in tetralogy of Fallot of tricuspid atresia can easily be visualized. In some instances a cardiac catheterization may be necessary to better clarify the heart anatomy.
Complications :
There may be failure to thrive or just difficulty in joining in games and sports with other children.
A right to left shunt can permit paradoxical embolism that may present with a systemic embolism such as a stroke.
A left-to-right shunt does not cause cyanosis but the high volume pumped by the right side may result in pulmonary hypertension and, if this builds up and exceeds systemic pressure, the shunt may reverse from right to left. This is called Eisenmenger’s complex and it may not develop until the child is an adolescent or adult.
Cyanosis results in polycythaemia; a haemoglobin value as high as 20 g/dL may cause additional difficulty as the blood is so viscous.
Treatment
Most of all cyanotic heart defects ultimately require surgery for definitive treatment. Prior to surgery, medication may be necessary to stabilize the patient. In patients with severe cyanosis,a medication called prostaglandin may be used to keep the ductus arteriosus open to allow blood to enter the lungs.
Atrial Septostomy.
In cases of life threatening cyanosis and/or pulmonary hypertension a ballon atrial septostomy is done by threading a wire through the foramen ovale and inflating a balloon to open the foramen ovale, this allows adequate mixing in case of ransposition of great arteries and relieves pre right sided pressures in setting of pulmonary hypertension.
Surgery for cyanotic heart defects may often initially involved placement of a shunt as a means for blood to enter the lungs (Blalock Taussig shunt). This often is followed by either definitive repair or further palliation, such as seen with a Fontan procedure. With everyday advancement in pediatric cardiothoracic anesthesia and cardiopulmonary bypass the neonatal surgeries are more safe. The management of congenital heart disease has improved so much over the years that many affected children are now adults.
Outlook for Cyanotic Congenital Heart Disease
The outlook for cyanotic congenital heart disease is varies based on the severity of the underlying defects present in the child. In mid cases, the child may be able to live a normal lifestyle with minimal medications or other treatments. In the most severe cases, when surgery is needed soon after birth, the outlook is not as good. The prognosis for children with congenital heart disease has improved dramatically over a 20-year period. It is predicted that 78% of the babies born with congenital heart disease today will survive into adulthood.
(The author is Cardiac Surgeon SSH, Jammu)
Follow our WhatsApp channel
