Usefulness of dobutamine stress myocardial contrast echocardiography for assessing coronary artery disease.
BACKGROUND
Quantitatively assessing myocardial perfusion and its reserve is of great importance for the diagnosis and stratification of patients with coronary artery disease (CAD), and represents an important goal of myocardial contrast echocardiography. In this study we sought to test the usefulness of low dose dobutamine stress real-time myocardial contrast echocardiography (RT-MCE) in the assessment of CAD, and to explore the relationship between perfusion reserve and contractile reserve.


METHODS
Twenty-six patients with suspected or clinical diagnosed CAD were enrolled and underwent RT-MCE at baseline and under low dose dobutamine stress, and subsequent coronary angiography. RT-MCE images were analyzed quantitatively from microbubble replenishment curves for myocardial perfusion and its reserve.


RESULTS
At baseline, significant differences in beta (0.28 +/- 0.12, 0.25 +/- 0.09, 0.22 +/- 0.06, 0.20 +/- 0.07 respectively, P < 0.01) and A x beta (1.37 +/- 0.46, 1.28 +/- 0.47, 1.13 +/- 0.37, 0.91 +/- 0.32, respectively, P < 0.01) were observed among four segment groups with graded coronary artery stenosis severity (normal; 30% - 69% stenosis; 70% - 90% stenosis; and beyond 90% stenosis), but not observed in parameter A. When under stress, significant differences in A (5.73 +/- 1.28, 5.63 +/- 1.01, 4.96 +/- 0.81, 4.57 +/- 0.62, respectively, P < 0.01), beta (0.67 +/- 0.17, 0.55 +/- 0.19, 0.32 +/- 0.13, 0.25 +/- 0.08, respectively, P < 0.01) and A x beta (3.81 +/- 1.20, 3.11 +/- 1.17, 1.59 +/- 0.82, 1.12 +/- 0.37, respectively, P < 0.01) were observed among the formerly mentioned groups. Graded decreases in A reserve (1.20 +/- 0.53, 1.11 +/- 0.16, 0.98 +/- 0.12, 0.99 +/- 0.13, respectively, P < 0.01), beta reserve (2.65 +/- 1.07, 2.32 +/- 0.82, 1.44 +/- 0.40, 1.29 +/- 0.34, respectively, P < 0.01) and A x beta reserve (3.05 +/- 1.63, 2.59 +/- 1.01, 1.42 +/- 0.44, 1.27 +/- 0.34, respectively, P < 0.01) could also be observed with increasing coronary stenosis severity. In five segments groups scored by WMS (1 - 5), concordance between contractile function and myocardial perfusion could be found both at rest (beta: 0.28 +/- 0.11, 0.22 +/- 0.08, 0.21 +/- 0.05, 0.17 +/- 0.05, 0.19 +/- 0.06, respectively, P < 0.01; A x beta: 1.29 +/- 0.48, 0.98 +/- 0.45, 0.94 +/- 0.29, 0.76 +/- 0.30, 0.92 +/- 0.32, respectively, P < 0.01) and under stress (beta: 0.59 +/- 0.20, 0.35 +/- 0.15, 0.27 +/- 0.08, 0.17 +/- 0.05, 0.20 +/- 0.05, respectively, P < 0.01; A x beta: 3.07 +/- 1.38, 1.62 +/- 0.82, 1.28 +/- 0.40, 0.78 +/- 0.24, 0.93 +/- 0.22, respectively, P < 0.01). This concordance is also valid in terms of the reserves, and the MCE parameters in segments with ameliorated contractile function are significantly higher than in those without.


CONCLUSIONS
Quantitative RT-MCE in conjunction with dobutamine stress shows promise in identifying and stratifying CAD and in exploring the perfusion-contractile correlation.
Guo
Shi-zun
SZ
Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
Shu
Xian-hong
XH
Pan
Cui-zhen
CZ
Li
Yan-lin
YL
Ge
Jun-bo
JB
Chen
Hao-zhu
HZ
D000328:Adult; D000368:Aged; D003287:Contrast Media; D017023:Coronary Angiography; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D015203:Reproducibility of Results
D003287:Contrast Media; D004280:Dobutamine