Detection of coronary stenoses at rest with myocardial contrast echocardiography

Area of Science:

• Cardiovascular imaging
• Echocardiography
• Coronary artery disease

Background:

• Autoregulatory changes in arteriolar blood volume (aBV) distal to coronary stenosis are hypothesized to be measurable.
• Current methods often require stress for coronary stenosis detection.

Purpose of the Study:

• To evaluate myocardial contrast echocardiography (MCE) for detecting coronary stenosis at rest.
• To assess if changes in aBV distal to stenosis can be measured non-invasively.

Main Methods:

• High-mechanical-index MCE at 15 Hz was used in patients with varying degrees of coronary artery stenosis.
• Phasic changes in aBV in intramyocardial vessels were measured using Definity or Imagent contrast agents.
• Systolic/diastolic aBV signal ratios were calculated and correlated with stenosis severity.

Main Results:

• Significant increases in aBV were observed distal to coronary stenoses.
• A systolic/diastolic aBV ratio >0.34 showed 80% sensitivity and 71% specificity for >75% stenosis (Definity).
• A ratio >0.43 showed 89% sensitivity and 74% specificity for >75% stenosis (Imagent).

Conclusions:

• Coronary stenosis presence and severity can be detected at rest using MCE.
• Measuring increased aBV distal to stenosis via MCE provides a non-stress diagnostic tool.
• This technique allows for coronary stenosis detection without the need for stress protocols.