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Quantitative assessment of coronary stenosis by harmonic power Doppler with a simple pulsing sequence and vasodilator
Yuichiro Takagi1, Koji Ohmori, Kazushi Yukiiri
1Second Department of Internal Medicine, Kagawa Medical University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, Japan 761-0793.
Insights
Myocardial contrast echocardiography (MCE) with harmonic power Doppler (HPD) can assess coronary artery stenosis severity. Shortening the pulsing interval (PI) during vasodilator stress improves accuracy in detecting significant blockages.
Area of Science:
- Cardiovascular imaging
- Echocardiography
- Interventional cardiology
Background:
- Myocardial contrast echocardiography (MCE) intensity depends on myocardial blood flow velocity (MBFV) and pulsing interval (PI).
- Accurate assessment of coronary artery stenosis is crucial for patient management.
Purpose of the Study:
- To evaluate if MCE with harmonic power Doppler (HPD) and a simple ultrasound pulsing sequence can estimate coronary artery stenosis severity.
- To determine the correlation between MCE-derived parameters and quantitative coronary angiography (QCA) or fractional flow reserve (FFR).
Main Methods:
- Developed an MBFV index based on contrast intensity decay during PI shortening.
- Acquired HPD images during intravenous Levovist infusion in 68 coronary territories.
- Compared MCE-derived MBFV index and MBFV reserve with QCA and FFR under baseline and hyperemia conditions.
Main Results:
- MCE-derived MBFV index and MBFV reserve showed significant negative correlations with stenosis severity (r = -0.56, r = -0.64).
- MBFV reserve positively correlated with FFR (r = 0.89).
- Combined MCE parameters accurately identified >75% stenoses (77.3% sensitivity, 93.4% specificity).
Conclusions:
- Shortening PI during MCE with intermittent HPD imaging under vasodilator stress allows for patient coronary artery stenosis assessment.
- This technique offers a non-invasive method for evaluating coronary artery disease severity.
Objectives:
We examined whether myocardial contrast echocardiography (MCE) with harmonic power Doppler (HPD) employing a simple ultrasound pulsing sequence enables estimation of the severity of coronary artery stenosis in patients.
Background:
Contrast intensity (CI) during MCE with intravenous microbubble infusion is dependent on the myocardial blood flow velocity (MBFV) and pulsing interval (PI).
Methods:
Based on an in vitro experiment, we devised the MBFV index calculated as the reciprocal of the magnitude of CI decay produced by abrupt PI shortening during intermittent imaging. In 68 coronary artery territories from 49 patients, myocardial HPD images were acquired during intravenous infusion of Levovist, while the long PI with 1:10 electrocardiographic gating was shortened to 1:1, both at baseline and during adenosine triphosphate infusion. The MBFV index in each coronary territory and MBFV reserve as the ratio between hyperemia and baseline were compared with the severity of corresponding coronary artery stenosis assessed by quantitative coronary angiography (QCA) or by pressure guide wire as the fractional flow reserve (FFR).
Results:
Both the MCE-derived MBFV index during hyperemia and MBFV reserve exhibited significant negative correlations with the QCA-derived stenosis severity (r = -0.56 and r = -0.64, respectively). The MBFV reserve positively correlated with FFR (r = 0.89). By combining the cutoff values of the MBFV index during hyperemia and MBFV reserve, > or =75% of stenoses defined by QCA were determined, with a sensitivity of 77.3%, specificity of 93.4%, and accuracy of 88.3%.
Conclusions:
Shortening of PI during intravenous MCE with intermittent HPD imaging under vasodilator stress enables assessment of coronary artery stenoses in patients.
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