Coronary artery anomalies

What is Coronary artery anomalies?

Coronary artery anomalies is a group of congenital heart defects characterized by abnormal development of the coronary arteries: an unusual number of vessels, their origin and the location.

Embryology

Extramural vessels begin to develop from the base of the aorta, protruding to the apex of the heart. They have penetrating branches that enter the myocardium and connect to the primitive system of sinusoids. The same structures develop in the base of the pulmonary artery. Violation in development of the coronary arteries at any stage leads to the formation of anomalies.

Classification

1. Anomalous left coronary artery from the pulmonary artery.
2. Anomalous origin of the right coronary artery.
3. Coronary arterial fistulas.
4. Anomalous aortic origin of a coronary artery.
5. Coronary artery aneurysm in Kawasaki disease.

Anomalous left coronary artery from the pulmonary artery

Anatomy

Anomalous left coronary artery from the pulmonary artery is more common as an isolated defect, but can also be combined with other heart defects. The anomalous left coronary artery usually departs from the pulmonary sinus adjacent to the Aorta. It can also depart from any other sinus of Valsalva. Stenosis of the coronary artery may occur among some patients. The right coronary artery, which becomes the main source of blood supply to the heart, becomes significantly dilated. In the adult type of defect, coronary collaterals are formed, which lead to coronary stealing. Progressive ischemia leads to dilatation of the heart, mainly the left ventricle, severe endocardial fibroelastosis, hypertrophy and deformation of the papillary muscles and sclerosis. Often it manifests in subendocardial or transmural left ventricular myocardial infarction.

Hemodynamics

This anomaly does not have a negative effect on hemodynamics in the prenatal period, as the pressure and blood oxygen saturation in the aorta and pulmonary artery are the same. Myocardial perfusion is normal and there is no incentive for the development of collateral vessels. After birth, desaturated blood circulates in the pulmonary artery. With the natural regression of the muscle layer of the pulmonary vessels walls and a decrease in pressure in the pulmonary artery to a normal level, the left ventricle is supplied with desaturated blood at low pressure. By this time, the blood flow through the collaterals is still insignificant.

The left ventricular myocardial vessels expand to reduce their resistance and increase blood flow as the first adaptive reaction. However, the vascular reserve is soon depleted, and myocardial ischemia intensifies. Initially, ischemia is intermittent in nature and occurs only during stress situations associated with feeding and crying. 

A further increase in oxygen demand of the myocardium leads to infarction of the anterolateral wall of the left ventricle, heart weakness and mitral regurgitation due to dilatation of the left ventricle or to the infarction of the anterior papillary muscle.

Blood supply of left ventricular myocardium depends on the degree of collateral development, pressure in the left coronary artery and the severity of the phenomenon of blood leakage into the pulmonary artery (coronary steal syndrome).

Workup

• Echocardiography, CT. Visualization of the defect, anatomical characteristics.   
• ECG. The electrical axis of the heart is deflected to the left. In subcompensation and compensation, there are signs of left ventricular myocardial hypertrophy with subendocardial ischemia. In the stage of decompensation - the picture of acute myocardial infarction.
• Chest X-ray. Cardiomegaly, mainly due to the left heart, and signs of pulmonary venous hypertension.
• Cardiac catheterization with aortography. It is necessary for defect verification in most cases.

Clinical presentation

Clinical presentation depends on the collateral’s development between the two coronary systems. Two clinical and hemodynamic types reflect the age-related dynamics of coronary circulation in this pathology: infantile (with a small number of intercoronary anastomoses) and adult (a large number of intercoronary anastomoses that ensure long-term survival).

The disease manifests itself most often during the first months of life. The first signs are a violation of the general condition, lethargy, pallor of the skin, excessive sweating, vomiting, regurgitation, dyspnea, and tachycardia. Half of the patients have bouts of sudden sharp anxiety with increased dyspnea, pallor, and sweating. Dyspnea and diarrhea are typical symptoms of this defect. Many children in the stage of decompensation of the disease lag behind in physical development. The borders of the heart are expanded mainly to the left and indicate cardiomegaly. 

Heart sounds are often reduced in intensity; systolic murmur of mitral valve insufficiency and continuous soft continuous murmur in the II intercostal space on the left are often heard. Left ventricular heart failure is more common.

Treatment

There are several surgical methods for this defect:

1. Reimplantation of the coronary artery in the aorta.
2. Takeuchi surgery (creating a tunnel inside the pulmonary trunk). This operation is performed in the absence of favorable conditions for direct reimplantation of the left coronary artery into the aorta.
3. Modified Takeuchi surgery. The modified technique involves the construction of a tunnel using a Gore-Tex. This modification is especially useful if the output part of the coronary artery is located on the left edge of the pulmonary trunk.

Shunting procedures for creating antegrade blood flow through the left coronary artery.

Anomalous origin of the right coronary artery

1. Anomalous origin of the right coronary artery or its branches from the left sinus of Valsalva.

Anomalous origin of the right coronary artery from the left sinus of Valsalva is about 30% of all anomalies of the coronary arteries. The artery passes between the aorta and the outflow tract of the right ventricle.

2. Anomalous origin of the right coronary artery originating from the pulmonary trunk.

An abnormal origination of the right coronary artery from the pulmonary trunk is much less common than of the left coronary artery. The right coronary artery originates from the right pulmonary sinus, passes in the right atrioventricular sulcus, and branches normally. Usually, in such an anomaly, collateral vessels are well developed, the left coronary artery is usually dilated. The course of the defect is worse with the right type of blood circulation. Clinically, this defect proceeds asymptomatic, without any clinical signs or ECG signs of ischemia. In this situation, surgical treatment is indicated not for all patients.

Coronary arterial fistulas

Anatomy

The coronary arterial fistulas are rare as an isolated defect, most often they are associated with atresia of the pulmonary artery with an intact interventricular septum. Anatomically, a fistula is a dilated convoluted vessel that communicates with heart chambers, the coronary sinus or heart veins.

Hemodynamics

Usually, fistulas do not significantly affect hemodynamics, but can lead to coronary stealing.

Diagnostics

• Coronary angiography, echocardiography, CT, MRI. Visualization of defects.
• Chest X-ray. Changes appear in the presence of a pronounced shunt in the form of cardiomegaly due to dilatation of the left ventricle and the cavity of the heart into which the blood is shunted.
• ECG. There may be signs of ventricular hypertrophy, ischemic changes.

Clinical presentation

The clinical presentation of the coronary fistulas ranges from asymptomatic to severe heart failure. Symptoms are usually absent until approximately 20 years of age. At a young age, atrial fibrillation, fatigue, dyspnea during physical exertion, ischemic pain appear, myocardial infarction develops.

Auscultation: a continuous systolic-diastolic murmur is well heard on the left and right edges of the middle part of the sternum.

There is a definite connection between auscultatory manifestations and the fistula inflow. If the fistula opens into the right or left atrium, then the systolic component of the murmur with a medium-systolic amplification prevails. 

If it opens into the left ventricle, there is a loud diastolic component (blood shunt goes mainly to the diastole). If the fistula opens into the right ventricle, the middle diastolic component is louder than the middle systolic.

Treatment

Surgical treatment is indicated for all symptomatic patients. The feasibility of surgical treatment for the patients with minor coronary fistula is currently under discussion, as a progressive increase in the size of the fistula is possible. The modern development of interventional cardiology allows closing small fistulas, regardless of the volume of shunted blood. Larger fistulas must be removed surgically.

Anomalous aortic origination of a coronary artery

Anatomy

The following abnormalities of the coronary arteries extending from the aorta are distinguished:

1. A tangential course of the coronary arteries from the aorta.
2. Anomalous coronary artery course between the aorta and pulmonary artery.
3. Anomalous origin of the left main coronary artery from the right sinus of Valsalva.
4. Anomalous origin of the right coronary artery from the left sinus of Valsalva.
5. A single coronary artery.
6. Intramural coronary arteries.
7. Myocardial «bridges».

Workup

Diagnostics carried out by cardiac catheterization, angiocardiography, echocardiography, CT, MRI.

Treatment

Treatment options include coronary plastic or relocation.

Coronary artery aneurysm in Kawasaki disease

In Kawasaki disease, aneurysms, thrombosis, and arterial panvasculitis are observed. Both coronary arteries can be affected. The disease may be asymptomatic until the development of ruptured aneurysms or myocardial infarction. Such patients need surgical intervention: resection of the aneurysm, coronary artery bypass grafting or ligation of the affected artery.