Introduction
The human heart is a highly structured and regulated organ. Any form of error during the development of the heart can bring in severe cardiac abnormalities and anomalies. The cardiovascular system is the initial organ system established in a developing baby during the intrauterine (within the womb) stage. The baby's heart becomes functional within the first four weeks of pregnancy, so by then, all the heart chambers and the associated blood vessels will be formed. But in some babies, the heart develops anomalies or deviations from what is identified as normal anatomy and structure, which directly influence the way the heart functions and supports all other systems in the body.
What Is Arterial Switch Operation?
Arterial switch operation is a highly intricate surgical intervention adopted to correct a specific inborn defect called transposition of the great arteries (TGA). As the name implies, it involves switching or reversing the arteries wrongly attached to the heart due to an inborn defect. This operation is mainly done on newborn babies on an emergency basis within the first seven days of life. It is a life-saving procedure that allows infants born with TGA to survive and overcome the functional deficit. It is quite an extensive procedure, which is carried out in the form of open heart surgery. Dr. Adib Jatene first demonstrated arterial switch operation, and hence, it is also known by the name Jatene switch procedure.
What Is the Transposition of the Great Arteries?
The transposition of the great arteries is an alarming and lethal inborn heart defect, where the two key arteries stemming from the heart chambers are reversed. This reversal of the arteries impairs cardiac function.
The heart encompasses four distinct chambers, two on either side of the heart (right and left). The upper compartments are denoted as atria, while the lower ones are ventricles. To easily identify the chambers, they are often named along with the side they belong to (right atrium and left ventricle). The heart and lungs function in connection to ensure unhindered delivery of oxygen-loaded blood to every cell in the body. The heart-lung association is established through pulmonary blood vessels (pulmonary artery and pulmonary vein), which bridge the circulation across the lungs and heart. The right side of the heart gathers all the oxygen-deficient blood from across the body and presents it to the lungs via the pulmonary artery. Meanwhile, the left side gathers oxygen-loaded blood from the lungs and presents it across the body via the aorta. In normal anatomy, the pulmonary artery should stem from the right ventricle to drive out the blood for oxygen enrichment, and the aorta stems from the left ventricle, presenting the oxygen-enriched blood to the body.
In TGA, these two major blood vessels (pulmonary artery and aorta) originate wrongly. The pulmonary artery emerges from the left ventricle instead of the aorta and vice versa. As a result of this reversal, oxygen-deprived blood keeps circulating without getting enriched with oxygen molecules. Oxygen-loaded blood will be restricted to the left chamber and lungs and move around the loop without access to other cells to supply.
How Does Arterial Switch Operation Tackle the Transposition of the Great Arteries?
It is a complex procedure in newborn babies identified with the transposition of great arteries. In this procedure, wrongly emerged arteries will be detached from the wrong sites and reattached to the intended sites where they should be present so that the heart can deliver oxygenated blood. A series of intricate procedures involved in the arterial switch operations include the following:
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General Anesthesia: The baby should be given general anesthetic medications that make the child sleep and ensure that the baby remains unconscious throughout the procedure.
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Chest Incision: An incision is made in the chest region to expose the heart and to achieve proper access to the treatment site. The exposure is often made through the breast bone (sternum), which is present at the central portion of the chest.
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Cardiopulmonary Bypass: Since the surgical intervention is performed on the heart, machinery assistance is required to maintain the heart-lung functions, which is done through the cardiopulmonary bypass. It is a heart-lung bypass machine often employed during open-heart surgeries.
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Arterial Switch: This is the crucial procedure in arterial switch operations, where the wrongly stemmed aortic and pulmonary arteries will be disconnected from the cardiac attachments right from the attachment base and then engaged back to the correct position. The arteries concerned with the heart's blood vessels (coronary arteries) must also be switched to the new aorta.
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Correction of Atrial Septal Defect: Most babies diagnosed with TGA are reported to have a perforation in the wall that separates the upper right and left compartments. Such defects are medically known as atrial septal defects. In arterial switch operation, the atrial septal defect is also rectified along with the arterial reversal. In addition, if the baby's heart has another rectifiable cardiac defect, that will also be given attention.
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Monitoring the Cardiac Functions: Once all the corrections are made, the functioning of the baby's heart is monitored by slowly disengaging the machinery support (heart-lung bypass).
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Surgical Closure of the Chest Incision: After verifying and validating the heart's performance, surgical closure is achieved with sutures.
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Post-surgical Monitoring: The baby will be monitored closely following the surgery, keeping track of cardiac functioning. It aids in checking the development of complications.
What Are the Complications Associated With an Arterial Switch Operation?
Arterial switch operation offers promising results with remarkable success rates. However, it does pose certain risks and complications. Some of the complications include:
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Breathing issues.
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Arrhythmia (heart beating out of rhythm).
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Swallowing issues.
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Vomiting.
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Blood clot formation.
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Stroke (hindered blood flow to the brain).
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Trauma to the vocal cord (part of the sound box).
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Cardiac arrest (heart ceases beating).
Conclusion
Arterial switch operation is the indicated surgical repair for babies with transposition of the great arteries. It is a promising surgical intervention with a success rate of 99 percent that helps extend the longevity of TGA patients. Thorough preoperative analysis and examination of the child's health status, often carried out by a panel of specialist doctors, ensures the procedure's success. Following the procedure, the baby will be given certain medications to be continued for the long term to keep the heart functional and stable.
