Coronary artery compression is defined as the narrowing of the left main coronary artery (LMCA) between the aorta and a dilated pulmonary artery main trunk. Recently it has been found that coronary artery compression is a vital cause of sudden death in children fitted with epicardical pacemakers.
The LMCA compression is caused by an enlarged pulmonary artery main trunk, which is a syndrome that is associated with severe pulmonary artery hypertension. This syndrome is commonly observed in cases of congenital cardiac defect, atrial septal defect, ventricular septal defect, or tetralogy of Fallot (a combination of four congenital defects including ventricular septal defect, pulmonary valve stenosis, a misplaced aorta, and right ventricular hypertrophy).
The LMCA compression is one of the main causes of chest pain associated with pulmonary artery hypertension. Apart from severe chest pain, LMCA compression is also associated with myocardial ischemia, myocardial infarction, left ventricular dysfunction, arrhythmia, and sudden death. Since the incidence of LMCA compression is not well established in pulmonary artery hypertension, clinical presentations often include cardiogenic shock and malignant arrhythmia caused by myocardial ischemia and sudden death.
Diagnosis and treatment of LMCA compression is not well defined in the literature, despite the recent advancements in therapeutic intervention. Diagnosis is mainly achieved using a computed tomography (CT) scan, coronary angiography, and intravascular ultrasound. A treatment strategy that has shown promising outcomes is percutaneous coronary intervention, which is a non-surgical process of placing a stent (a small metallic or plastic structure) using a catheter to open up the compressed segment of the artery.
Coronary Artery Compression in Children
Coronary artery compression is a serious complication in children who are fitted with epicardical pacemakers or defibrillators. The procedure of fitting the epicardical pacemaker or defibrillator frequently involves placement of the wire on the outside of a child’s heart due to the size and unique anatomy of the heart. These wires can potentially increase the risk of cardiac strangulation (a rare but potentially fatal complication caused by epicardical pacemaker leads) in children, which can ultimately result in compression of the heart muscle and coronary arteries.
Incidences of coronary artery compression are believed to be a very rare complication in children with epicardial pacemakers, this is due to lack of data in the literature and lack of awareness of the condition. A recent study has revealed that approximately 5.5% of children with epicardial pacemakers are diagnosed with coronary artery compression. Approximately 75% of these children exhibit other symptoms such as chest pain and fatigue, additionally there was one incidence of sudden death during this study.
Diagnosis of Coronary Artery Compression in Children
One of the best possible ways of detecting coronary artery compression in children is to perform a screening chest x-ray. As the position of the epicardical wire may change with child’s growth, children with epicardical devices should undergo a chest x-ray analysis every few years to avoid potential health hazards. Chest x-ray is the most recommended screening technique for children because it is highly specific, easy to perform, inexpensive, and non-invasive.
Besides chest x-ray, another important tool is Ultrafast (Cine) CT scan, which can potentially image the movement of the heart in relation to epicardical wires. This non-invasive technique is less risky for children because a very low dose of radiation is used to image the heart.
Management of Coronary Artery Compression
Although coronary artery compression is a serious health complication, it is potentially treatable if diagnosed at an early stage. To avoid its potential life-threatening consequences, surgeries are generally performed to either remove or reposition epicardical wires. It is also recommended to carefully evaluate the potential site of electrode head fixation and the route of the electrode body to the epicardical device.
It is of prime importance to increase the awareness of this condition among healthcare professionals. A greater understanding of the risk factors, symptoms, potential screening tools, and surgical interventions associated with coronary artery compression in children whom are fitted with epicardial pacemakers will greatly benefit children that suffer from this condition.