Coronary artery anomalies

Definition

Congenital anomalies of the coronary arteries are diagnosed in about 1-2% of people. In cardiac surgery, they are in second place among pathologies that lead to sudden infant mortality. If there is a suspicion of the disease, it is necessary to urgently consult a doctor and undergo the prescribed examination and treatment. 

Types of coronary artery anomalies:

Among the most common coronary abnormalities, doctors cite:

• coronary arteries orifice pathology;
• arterial hypoplasia – a decrease in the diameter of the vascular bed;
• coronary fistulas – fistulas that form between an artery and one of the chambers of the heart;
• a change in the number of vessels – for example, a single right or left coronary vessel.

There are different types of coronary anomalies surgical treatment, for example, you can have a Coronary artery anomalies surgery in 21 clinics across the world (https://doctor.global/results/procedures/coronary-artery-anomalies-surgery). 

The most frequent anomaly of this group is coronary fistula, which we will discuss in more detail below.

Coronary fistula is a variant of coronary valvular anomalies in which blood drains from the coronary vessel into the heart chambers or large vessels. In early life, the condition is manifested by sweating, slow weight gain, and skin lividity. In adults with a vascular anomaly, there are signs of heart failure. The main diagnostic methods are echocardiography, selective coronarography, and CT. ECG and chest X-ray are also used. Radical malformation treatment involves transcatheter occlusion of the coronary fistula or surgical correction of the anomaly.

General information

Coronary artery fistula is a rare malformation, accounting for 0.2-0.4% of all congenital malformations of the cardiovascular system. Although the condition can be diagnosed at any age, it is more often diagnosed in newborns and early childhood. No statistically significant sex or racial differences have been found among patients with coronary fistula. Fistulas with a single communication are common, but multiple defects also occur.

Reasons

The exact etiology of the malformation has not been established. The anomaly is believed to be formed in the early period of intrauterine development. At this time, the fetus has sinusoidal messages that are needed to maintain blood flow in the myocardium. A coronary anomaly may occur if such vascular branches do not close before birth.

Another theory of fistula formation points to malformations of the distal segments of the coronary arteries. In this case, abnormal shunts exist between the coronary vessels and the ventricular cavities instead of normal vessels that feed the heart muscle. The etiologic factor of coronary vascular anomaly is various variants of blood flow obstruction, such as pulmonary atresia.

Classification

There are many classifications of coronary valvular anomaly in clinical cardiology. All fistulas are categorized into two groups:

• Congenital (98-99%), which are combined with other malformations;
• Acquired, formed after surgical interventions on myocardium or venous vessels.

The type of fistula drainage is of clinical importance in determining the severity of symptoms. Cardiologist and cardiac surgeon Hans Bankl distinguishes two types of fistulae:

• Arteriovenous fistulas. About 90% of these coronary anomalies are congenital. The coronary artery anastomoses with the right heart, coronary sinus, or pulmonary trunk.
• Arterio-arterial fistulas. This malformation involves anastomoses of vessels feeding the myocardium with the left atrium or ventricle. It is observed in 10% of patients.

More than 50% of malformations are formed in the right coronary artery, 46% – in the left, and 4% are bilateral fistulas in both coronary vessels. Single and multiple pathologic vascular anastomoses are also distinguished. According to the diameter of the formed shunt, a distinction is made between small coronary fistulas with an orifice size of less than 2 mm and large fistulas with an entrance opening of more than 2 mm.

Symptoms of coronary fistula

Most small coronary anomalies are asymptomatic. In large coronary fistulas in infants, there are attacks of increased nervous excitability and sweating. After 2-3 months of life, infants experience rapid fatigue when feeding and poor weight gain. When screaming, the skin around the mouth acquires a livid color. Sometimes, wheezing in sleep is heard.

Adult patients gradually develop symptoms of heart failure. One of the first signs is shortness of breath and palpitations that occur during physical exertion. Constant weakness and decreased efficiency are characteristic. Patients notice swelling of the legs, which increases in the evening. Sometimes, there is pain in the precardiac region, which resembles an attack of angina pectoris.

Complications

Small fistulas rarely produce complications, but they dilate over time, increasing the risk of coronary aneurysm formation. Large undiagnosed shunts are associated with an increased risk of sudden cardiac death in young adults aged 20-35 years. The incidence of complications increases with age. 80-90% of patients gradually develop chronic myocardial ischemia, which, if untreated, leads to ischemic cardiomyopathy.

A dangerous complication is the rupture of the aneurysmal extension of the fistula, which is accompanied by hemopericardium and cardiac tamponade. Chronic overloading of the heart with blood volume causes congestive heart failure. Coronary fistulas in 20-30% of patients are a predisposing factor for early onset of venous artery atherosclerosis. Sometimes, myocardial infarction occurs due to thrombosis of the fistula.

Diagnosis

Children are examined by a pediatrician and a pediatric cardiologist; adult patients require consultation with a general practitioner-cardiologist. In small anomalies, there are no objective symptoms of the disease. With large fistulas, pathologic heart murmurs and muffled tones are detected. To confirm the malformation, instrumental studies are used:

• Echocardiography. Cardiac ultrasound is the “gold standard” of diagnosis, showing dilatation of the affected coronary artery and the presence of a pathologic shunt. Mapping is performed to measure the volume of blood flow through the fistula.
• Electrocardiography. Specific changes are noted in large-diameter anastomoses. Left atrial and ventricular overload is indicated by a double-humped P wave, a deviation of the heart’s electrical axis to the left. Occasionally, signs of myocardial ischemia are registered on the cardiogram.
• CT. Computed tomography is the best noninvasive method for a three-dimensional reconstruction of the heart and the vessels that feed it. It can detect even distally located coronary fistulas.
• Coronarography. Selective coronary angiography with a contrast agent allows one to examine the course of the coronary vessel, the degree of its dilation, and the diameter of the fistula. Cardiac catheterization is additionally performed to assess the nature of blood flow.

Treatment of coronary fistula

Conservative therapy

Patients with small-sized fistulas without clinical manifestations are recommended to be monitored. If symptoms of coronary insufficiency appear during physical activity, symptomatic treatment is indicated. Considering the leading clinical symptoms, several drugs are prescribed: diuretics, beta-blockers, vasodilators, and others.

Surgical treatment

Surgical intervention is a method of radical treatment of coronary fistula with an orifice greater than 2.0 mm, as well as in cases of coronary dilatation greater than 5.0 mm. When choosing the optimal surgical technique, the number of fistula holes, the degree of hemodynamic disorders, and the coronary anomaly localization are considered. The main types ofsurgical interventions:

• Transcatheter occlusion. The technique is indicated in children with single fistulas without other cardiac defects. Occluders, spirals, or removable balloons are used to close the abnormal vascular communication.
• Surgical correction. Open surgery is recommended for multiple coronary fistulas in the presence of large vascular aneurysms. The operation aims to eliminate abnormal vascular passages and shows promising results even in combined cardiac pathologies.

All these types of treatment are available in more than 630 hospitals worldwide (https://doctor.global/results/diseases/coronary-artery-fistula). For example, Coil embolization of intracardiac shunts and fistulas can be done in 29 clinics across India for an approximate price of $3,8K (https://doctor.global/results/asia/india/all-cities/all-specializations/procedures/coil-embolization-of-intracardiac-shunts-and-fistulas). 

Prognosis and prevention

Patients with small coronary artery fistulas have no impairment in quality of life, and the risk of complications is minimal. The prognosis is also favorable after successful surgical correction of large shunts. Given the congenital nature of the disease, primary prevention measures have not been developed. To prevent complications, dispensary monitoring of patients with incidentally detected asymptomatic vascular anomalies is required.