[Diagnostic value of quantitative low-dose dobutamine stress echocardiography with three-dimensional speckle-tracking for non-ST-elevation acute coronary syndrome].

OBJECTIVE:To access left ventricular global deformation abnormalities during low-dose dobutamine stress test (DSE) by three-dimensional speckle-tracking echocardiography(3D-STE)in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS), and explore the diagnostic value of 3D-STE combined with DES for NSTE-ACS. METHODS:Forty-nine patients with suspected NSTE-ACS underwent DSE and coronary angiography with an initial dobutamine dose of 5 µg·kg(-1)·min(-1), which was doubled at 3-min intervals to the peak dose of 20 µg·kg(-1)·min(-1). The global longitudinal strain (GLS), global circumferential strain (GCS), territory longitudinal strain (TLS), and territory circumferential strain (TCS) of the left ventricular subendocardial myocardium were measured with 3D-STE at rest and at the peak-dose stage. Conventional echocardiography and 3D-STE parameters and their changes during DSE were evaluated, and their diagnostic values were analyzed according to the receiver-operating characteristic (ROC) curves. RESULTS:All the patients completed DSE uneventfully and 3D-STE showed a good reproducibility of the results. Compared with patients with non-NSTE-ACS, NSTE-ACS patients showed obviously reduced resting left ventricular global deformation function especially in terms of circumferential deformation (P<0.05); the ROC curves for the parameters were similar between the two groups (P>0.05). During DSE, the global deformation differences between the two groups further increased (P<0.01), and the diagnostic values of the peak-dose stage parameters were significantly greater than those of the resting parameters. ROC curves analysis showed that TLS and TCS at peak-dose stage had the highest diagnostic value for NSTE-ACS. CONCLUSION:3D-STE combined with low-dose DSE is a safe and effective noninvasive technique for accessing and identifying NSTE-ACS, and DSE can significantly enhance the diagnostic value of 3D-STE.