What is Coronary Cameral Fistula?
Coronary artery fistula are unusual links between the heart’s arteries and nearby structures. There are two types of these links: coronary cameral fistulae, which connect arteries to the heart’s chambers, and coronary arteriovenous malformations, that link arteries to other vessels in the body. A heart ultrasound can clearly show these abnormal links. Most of these fistulae are small and do not cause symptoms or complications, and they often fix themselves over time. However, large fistulae can cause symptoms and complications.
A fistula’s starting and ending points determine its type. The most common type starts in the right coronary artery and ends in the right ventricle of the heart. Mostly, these fistulae end in the right side of the heart, like the right ventricle or the right atrium. It is rare for them to end in the left atrium or left ventricle of the heart.
What Causes Coronary Cameral Fistula?
The main reason coronary cameral fistulae develop, which is a rare heart defect, is due to abnormal development while in the womb. However, other significant causes include:
1. Physical injuries: Things like stab wounds or gunshot injuries
2. Medical procedures: These could include tests to visualize the heart vessels (coronary angiography), pacemaker implantation, or samples taken from the inside of the heart (endomyocardial biopsy)
3. Heart surgery: Specifically, a procedure called septal myomectomy
Risk Factors and Frequency for Coronary Cameral Fistula
Coronary cameral fistulae are a rare condition, found in less than 1% of people and observed in only 0.1% to 0.2% of studies involving coronary angiography. These fistulae account for 0.2 to 0.4% of all congenital heart defects. When it comes to heart issues related to the coronary vessels in children, about half are due to these fistulae. This condition can be diagnosed at any age, but it’s usually discovered in early childhood. It often comes to light when a child without symptoms or a child showing signs of heart failure has a heart murmur detected. It’s interesting to note that this condition doesn’t seem to favor any particular gender or ethnicity.
- Coronary cameral fistulae are uncommon, existing in less than 1% of the population.
- They are observed in only 0.1% to 0.2% of coronary angiographic studies.
- These fistulae are accountable for 0.2 to 0.4% of congenital heart anomalies.
- About half of coronary vessel abnormalities in children are due to these fistulae.
- Diagnosis can happen at any age, usually in early childhood.
- Detection often happens when a heart murmur is heard in a child, with or without noticeable symptoms of heart failure.
- No particular gender or ethnicity is more likely to have this condition.
Signs and Symptoms of Coronary Cameral Fistula
Coronary cameral fistula patients may experience different symptoms based on the size of the shunt, which is a passage that diverts blood flow. When the shunt is small and does not affect the heart’s blood supply, symptoms may not be noticeable. However, in some instances, blood flow to the heart’s muscle tissues may be reduced, resulting in a condition called “coronary artery steal phenomenon.”
When this happens, patients can experience angina, a type of chest pain. Infants with angina may show sweating, irritability, rapid heart rate, and rapid breathing. Adults suffering angina due to this condition may report chest pain. Additionally, coronary cameral fistula can cause heart failure symptoms. In babies, this can show up as fatigue, fast breathing, excessive sweating while feeding, and failure to grow as expected. Older adults may experience difficulty breathing, heart palpitations, tiredness, trouble breathing while lying flat, sudden difficulty breathing at night, and swelling in the lower limbs.
A clinical exam can reveal numerous findings:
- A collapsing pulse
- A large difference between the high and low points of the pulse
- A widespread apex beat
- A discernable third heart sound (S3)
- A distinct, long-lasting heart murmur that gets louder in the middle to late diastole stage of the heartbeat
- Signs of heart failure
- Elevated jugular venous pressure, an S3 gallop (an abnormal heart rhythm), sounds of fluid in the lungs, an enlarged liver, fluid build-up in the abdominal cavity, and swelling in the lower limbs.
Testing for Coronary Cameral Fistula
If your doctor thinks you might have a heart condition known as a coronary cameral fistula, there are several tests they can do to confirm the diagnosis:
1. Lab tests: Your doctor may order lab tests that look for certain cardiac enzymes, and the B-type natriuretic peptide which tends to be elevated in patients with this condition, particularly those who also have heart failure.
2. Chest X-ray: While a chest X-ray usually comes back normal, in significant cases, it might show an enlarged heart chamber. It can also detect signs of heart failure, such as fluid build-up in the lungs.
3. EKG: An electrocardiogram (or EKG) is often normal, but in serious cases, it might note irregularities caused by inadequate blood flow or an enlarged heart chamber.
4. Echocardiography: Echocardiography, or ultrasound of the heart, can be used to help identify a coronary cameral fistula. In children, a transthoracic approach-looking at the heart through the chest wall-is often most useful. In adults, an approach that uses a small probe passed down the esophagus provides a clearer image. Echocardiography can also detect problems with the heart muscle itself.
5. CT scan: A CT scan can provide detailed pictures of the heart’s arteries, and can spot coronary cameral fistulas. A study in 2014 found that it was a useful tool for spotting these fistulas.
6. Cardiac catheterization and coronary angiography: These invasive tests provide a detailed map of your heart’s blood vessels and can help your doctor determine the size of the fistula and how much it is affecting your heart’s function.
7. Nuclear imaging: Nuclear imaging is done both before and after surgical repair. This test gives information about areas of your heart muscle that aren’t getting enough blood.
Treatment Options for Coronary Cameral Fistula
Dealing with coronary cameral fistulae, or abnormal connections between the heart and blood vessels, depends on numerous factors, such as where the fistula is located, its size, its structure, the patient’s age and symptoms, any complications like heart failure or infection, and whether other invasive procedures are needed.
According to the ACC/AHA 2008 guidelines for managing adults with inborn heart diseases, the recommendations for handling artery fistulae are:
1. If patients have a continuous murmur, the exact location and end of the fistula should be confirmed by echo scan, CT scan, or MRI.
2. Large fistulae, whether causing symptoms or not, should be closed either through a catheter or surgically after defining the precise structure of the fistula.
3. Fistulae of small to moderate size, causing complications such as reduced blood flow, irregular heartbeat, abnormal heart function, or inflammation of the artery should be closed either with a catheter or surgically after ascertaining the precise structure of the fistula.
As a general rule, small coronary cameral fistulae should be observed only with thorough echo or angiographic monitoring to track the expansion of the supplying vessels over time. These small fistulae are typically harmless, cause no symptoms, and may even close on their own. Conversely, large fistulae require closure through one of two methods: closure using a catheter or closure through surgery. Which technique to use for these fistulae will depend mainly on the medical team’s expertise caring for the patient. The surgical method might be more suitable for patients with large fistulae, multiple openings, abnormal enlargement, or sharp bends that do not permit catheterization.
Moderate-to-large fistulae, even without symptoms, are managed based on the fistula’s location. For proximal fistulae, closure through catheterization or surgery is recommended, followed by antiplatelet therapy for at least one year. However, for distal fistulae, two management approaches are possible. The first one is monitoring, combined with lifelong antiplatelet therapy, while the second one suggests fistula closure, followed by a year of antiplatelet therapy.
Importantly, it is not recommended to use preventive antibiotics against infection in isolated coronary cameral fistulae before procedures linked with causing blood-borne bacterial infection. However, preventive antibiotics would be appropriate if there is an existing inborn heart disease that increases cyanosis, or blueness due to lack of oxygen.
What else can Coronary Cameral Fistula be?
When doctors are trying to diagnose a heart condition called coronary cameral fistula, there are other conditions they have to rule out because they have similar symptoms. These include:
- Coronary arteriovenous malformation – an abnormal connection between the arteries and veins in the heart
- Pulmonary arteriovenous malformation – an abnormal connection between the arteries and veins in the lungs
- Intrathoracic systemic fistulae – abnormal connections between different parts of the body inside the chest
- Congenital systemic fistulae to the pulmonary veins – abnormal connections that are present from birth between the body’s main blood vessels and the veins in the lungs
- Ruptured aneurysm of the sinus of Valsalva – a bulging area in the major arteries of the heart that has burst
- Vasculitides such as Takayasu arteritis or Kawasaki disease – inflammation of the blood vessels resulting from certain medical conditions
It’s crucial for the doctors to differentiate between these conditions and ensure they arrive at the correct diagnosis.
What to expect with Coronary Cameral Fistula
People with a coronary cameral fistula generally live as long as those without the condition. Studies show that procedures using catheters or surgery to manage the condition are usually successful. Only a small fraction, about 4% of patients, might require extra surgery due to the recurrence of the condition.
Possible Complications When Diagnosed with Coronary Cameral Fistula
There are several complications related to coronary cameral fistulae, a heart condition. These can include:
- Cardiac ischemia (heart muscle damage due to lack of blood flow)
- Congestive heart failure (when the heart can’t pump enough blood to meet the body’s needs)
- Cardiac arrhythmia (irregular heartbeats)
- Infective endocarditis (infection of the heart’s inner lining)
- Rupture of coronary cameral fistula (a tear in the heart artery)
The management of coronary cameral fistulae involves procedures like transcatheter embolization and surgical closure. However, these also come with their own complications.
For transcatheter embolization, possible complications include:
- Coronary artery spasm (a sudden tightening of the heart muscle that temporarily decreases blood flow to the heart)
- Ventricular arrhythmia (an irregular heart rhythm that starts in the lower chambers of the heart)
- Coronary artery perforation or dissection (damage or tearing of the coronary artery)
- Cardiac ischemia from coronary artery thrombosis or improper positioning of occlusive devices (heart muscle damage due to a blood clot or the improper placement of a device that blocks blood flow)
For surgical closure, potential complications are:
- Cardiac ischemia or myocardial infarction (heart muscle damage or heart attack)
- Recurrence of coronary cameral fistula (the heart condition reoccurring)
Preventing Coronary Cameral Fistula
After leaving the hospital, it’s crucial for patients to have regular check-ups to monitor for any signs of heart problems or a recurring coronary artery fistula. Those who have had a procedure called transcatheter embolization or surgery to repair a coronary fistula will need to continue therapy with medications called antiplatelets. Sometimes, medications called anticoagulants may also be needed. This usually continues for the first 6 months after the procedure until the surface where the operation was done is fully healed. Patients with ongoing enlargement of the artery may benefit from extended antiplatelet therapy.
Patients who have had surgery should have frequent tests to measure stress levels on the heart and repeated imaging of the arteries, especially if there was loss of heart tissue due to the surgery.
Patients should also know about their disease, the different ways it can be managed, and the possible complications tied to the disease and its treatments. Understanding the need for regular check-ups after leaving the hospital is of utmost importance. Crucially, they should also know when to seek immediate medical care if their symptoms come back. If needed, it should be clearly explained to the patient on why sticking to the prescribed antiplatelet or anticoagulant therapy is a must. Being aware of the necessity to go under regular stress tests and repeated imaging of the arteries post-treatment is equally important.
