03/02/2023
Today's Pathology Review is all about coronary steal syndrome!
Coronary steal syndrome is a condition that occurs due to the dilation of coronary arteries in the presence of coronary artery disease.
Coronary arteries are linked to one another through teeny tiny blood vessels called collateral vessels, which are normally in an inactive state.
With coronary artery disease, there’s a decreased blood flow in a blood vessel. This means that the pressure inside this blood vessel is decreased, which causes the blood to rush in from the connected vessel (with normal pressure), through collateral circulation.
The sudden gush of blood through the collateral vessel stretches its walls and deforms the endothelial cells, which stimulates the production of growth factors that cause vasodilation and promote the proliferation of smooth muscle cells.
Coronary steal syndrome is a finding observed during a pharmacological cardiac stress test, which is used to diagnose coronary artery disease. During this test, a vasodilating medication like dipyridamole is given, which results in vasodilation of all coronary arteries, except the ones which are obstructed - because, beyond the obstruction, the coronary artery is already maximally dilated. Dilation of the non-obstructed coronary arteries decreases the pressure within them, so the pressure gradient across the collateral vessel vanishes, resulting in diminished collateral circulation.
The end result is that blood is diverted, or stolen, away from the ischemic myocardium to non-ischemic areas, which further worsens the ischemia. In severe cases, blood flow can be completely cut off, which results in myocardial infarction. Symptoms of coronary steal syndrome mimic that of myocardial infarction.
Coronary steal syndrome is diagnosed when the electrocardiogram shows an ST-segment depression during a pharmacological cardiac stress test.
Learn more about coronary steal syndrome on Osmosis: https://osms.it/path-coronary-steal-fb