coronary steal
A phenomenon where vasodilation of normal coronary arteries diverts blood flow away from areas supplied by stenotic vessels.
Full Definition
Coronary steal occurs when pharmacologic vasodilation or increased metabolic demand causes blood flow redistribution from regions supplied by stenotic coronary arteries to areas with normal vessels. This phenomenon is most commonly observed during pharmacologic stress testing with agents like dipyridamole or adenosine, which cause maximal coronary vasodilation. In patients with significant coronary stenosis, the vessels distal to the narrowing are already maximally dilated at rest, while normal vessels can dilate further with pharmacologic stimulation. This creates a pressure gradient that diverts flow away from the ischemic territory, potentially worsening ischemia despite increased overall coronary flow. The concept is fundamental to understanding pharmacologic stress testing and coronary physiology.
Usage
Usage note: Most relevant in the context of pharmacologic stress testing with vasodilator agents.
In Context
- "Adenosine stress testing revealed coronary steal phenomenon with worsening perfusion to the LAD territory despite increased global flow." — Nuclear stress test report
- "The patient's chest pain during dipyridamole infusion was attributed to coronary steal from the stenotic right coronary artery." — Stress echocardiography report