Clinical research: echocardiography
Assessment of the physiologic significance of coronary disease with dipyridamole real-time myocardial contrast echocardiography: Comparison with technetium-99m sestamibi single-photon emission computed tomography and quantitative coronary angiography

This work was presented in part at the 73rd Annual Meeting of the American Heart Association, New Orleans, Louisiana, November 2000.
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Abstract

Objectives

The purposes of this study were to test whether quantitative real-time myocardial contrast echocardiography (RT-MCE) can detect coronary disease during pharmacologic stress and to compare this approach with single-photon emission computed tomography (SPECT).

Background

Assessing myocardial perfusion during stress is important for the diagnosis and risk stratification of patients with coronary disease.

Methods

Thirty-five patients referred for coronary angiography underwent RT-MCE and technetium-99m methoxyisobutylisonitrile (MIBI) SPECT at baseline and after 0.84 mg/kg dipyridamole. The modalities of RT-MCE and SPECT were analyzed both qualitatively and quantitatively. For this purpose, myocardial flow reserve was calculated from microbubble replenishment curves, and regional MIBI uptake was measured on circumferential profiles. Segments and vascular territories were categorized into five groups with increasing stenosis severity by quantitative coronary angiography.

Results

With dipyridamole, beta and A × beta increased in all but the highest stenosis severity group. The increase in beta and A × beta was significantly lower in territories supplied by stenotic arteries than in those supplied by arteries with <50% stenosis. Graded decreases in beta and A × beta reserves were noted with increasing stenosis severity. Using the cutoff value of 2.00 for beta reserve, quantitative RT-MCE correctly identified 97% of the territories supplied by significant stenoses and 82% of those supplied by normal arteries. In contrast, quantitative SPECT correctly identified only 71% of the territories supplied by significant stenoses and 81% of those supplied by normal arteries.

Conclusions

This study shows that RT-MCE, with dipyridamole, can define the presence and severity of coronary disease in a manner that compares favorably with quantitative SPECT.

Abbreviations

CAD
coronary artery disease
LV
left ventricular
MBF
myocardial blood flow
MI
mechanical index
MIBI
methoxyisobutylisonitrile
QCA
quantitative coronary angiography
ROC
receiver-operating characteristics
RT-MCE
real-time myocardial contrast echocardiography
SPECT
single-photon emission computed tomography
99mTc
technetium-99m

Cited by (0)

This work was supported in part by grant no. 3-4563-98 from the “Fonds National de la Recherche Scientifique et Médicale” and grant no. 01/06-199 from the “Action de Recherche Concertée.” Dr. Peltier is supported by the “Société Française de Cardiologie,” Paris, France, and Dr. Ay by the “Damman Foundation,” Louvain-la-Neuve, Belgium.