Aim: To test whether quantitative stress echocardiography using contrast-based myocardial blood flow (MBF, ml.min−1.g−1) measurements can detect coronary artery disease in humans.
Methods: 48 patients eligible for pharmacological stress testing by myocardial contrast echocardiography (MCE) and willing to undergo subsequent coronary angiography were prospectively enrolled in the study. Baseline and adenosine-induced (140 μg.kg−1.min−1) hyperaemic MBF was analysed according to a three-coronary-artery-territory model. Vascular territories were categorised into three groups with increasing stenosis severity defined as percentage diameter reduction by quantitative coronary angiography.
Results: Myocardial blood flow reserve (MBFR)—that is, the ratio of hyperaemic to baseline MBF, was obtained in 128 (89%) territories. Mean (SD) baseline MBF was 1.073 (0.395) ml.min−1.g−1 and did not differ between territories supplied by coronary arteries with mild (<50% stenosis), moderate (50%–74% stenosis) or severe (⩾75% stenosis) disease. Mean (SD) hyperaemic MBF and MBFR were 2.509 (1.078) ml.min−1.g−1 and 2.54 (1.03), respectively, and decreased linearly (r2 = 0.21 and r2 = 0.39) with stenosis severity. ROC analysis revealed that a territorial MBFR <1.94 detected ⩾50% stenosis with 89% sensitivity and 92% specificity.
Conclusion: Quantitative stress testing based on MBF measurements derived from contrast echocardiography is a new method for the non-invasive and reliable assessment of coronary artery disease in humans.
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Funding: This work was supported by grants from the Swiss National Science Foundation (No 32-58945.99, to CS) and the Swiss Heart Foundation. The ultrasound equipment Acuson Sequoia was provided by Siemens Medical Solutions, Switzerland.
Competing interests: None.
Ethics approval: The study protocol was approved by the ethics committee of the Kanton of Bern, Switzerland, and written informed consent was obtained from all patients.