Coronary Slow Flow

Dr John Beltrame talks about the coronary slow flow phenomenon, and the angina associated with it.

Hello,

I’m Dr. John Beltrame, Senior Lecturer in Medicine at the University of Adelaide and the Queen Elizabeth Hospital Cardiology Unit. I joined the Editorial Advisory Board of the Virtual Cardiac Centre 2 years ago and today I would like to share with you my insights on the Coronary Slow Flow phenomenon.

Chest pain caused by heart disease is referred to as angina and typically arises from blockages in the large coronary arteries of the heart. Coroangiography is a technique that involves injecting dye into these coronary arteries by catheter and taking x-ray pictures to demonstrate the blockages. In patients whom the angiogram does not identify any significant blockages in the coronary arteries it is probable that the pain is not arising from the heart but may be due to other medical problems such as stomach ulcers.

However, in some patients with normal angiograms the pain may arise from the heart. One such group of patients are referred to as the Coronary Slow Flow phenomenon. Where the injected dye moves very slowly through the coronary arteries during coroangiography.

Studies of this phenomenon have discovered that these patients often undergo coroangiography after experiencing a severe episode of chest pain mimicking a heart attack. Fortunately, these patients seldom have heart attacks but it is not uncommon for the patients to continue experiencing recurring episodes of chest pain.

Further studies we, and others, have conducted demonstrate an abnormality in the microscopic blood vessels of the heart. In particular, these microscopic blood vessels develop spasm, which impairs blood flow and thus causes the angina chest pain. Moreover, the slow passage of the dye in the coroangiogram reflects the downstream resistance in these spastic microscopic vessels.

The treatment of patients affected by this condition predominantly involves preventing the recurring chest pain. Unfortunately, the standard treatments such as coronary bypass surgery, balloon therapies and stents, are not possible because of the microscopic nature of these vessels. Also, many drug therapies, which are often used in the treatment of angina have limited benefits as they target the large rather than the microscopic coronary vessels.

Although we did prove that one particular drug, mibefradil, did control the angina associated with the Coronary Slow Flow Phenomenon, this drug has unfortunately been withdrawn by the manufacturer due to its interaction with other drugs. Our ongoing research studies are directed towards finding other effective therapies for this disabling cardiac disorder.

Thank you for your interest.