| Objective1. To investigate the relationship between coronary slow flow and myocardialischemia by dobutamine stress real-time myocardial contrast echocardiography with myocardialblood flow （MBF） and MBF reserve.2. To explore vascular endothelial function in patients withcoronary slow flow. Methods1. Forty patients who underwent coronary artery angiographydue to chest pain were divided into CSF group（n=20） and control group（n=20） according to theircoronary artery angiography findings.2. The two groups referred for myocardial contrastechocardiography at baseline and after low dose dobutamine stress test. The images were analyzedand the time-amplitude curves were plotted by using the auto-tracking contrast quantification software. The maximal amplitude score A, the mean ascending slope of the curve β and the product ofA·β were measured. The reserve of A·β were also calculated.3. Electrocardiogram samples drawnat rest and each stage of dobutamine stress.4. Blood samples were drawn at rest and immediatelyat the end of Dobutamine stress test. Results1. Patients with coronary slow flow revealed higherframe counts in native coronary arteries than control subjects （P<0.01）.2. At baseline, the A, β andA·β were no significant differences between patients with coronary slow flow and control subjects.After Dobutamine stress test, the change of contrast score A in two groups was not significant.Both β and A·β were increased significantly in two groups. The β of the patients with coronaryslow flow were lower than control subjects (0.89±0.42s-1vs1.31±0.54s-1，P＜0.01), theA·β and A·β reserve （CFR） of the patients with coronary slow flow were also lower （5.82±2.69dB/s vs8.07±2.76dB/s，P＜0.05;1.82±0.85vs2.60±0.98，P＜0.05）.3. Electrocardiogram ofthe patients with coronary slow flow was normal at rest, but the electrocardiogram positive ratewas higher than control subjects after Dobutamine stress test （60%vs10%，p<0.01）. Patientswith more coronary arteries involved in slow flow phenomenon are more likely to have positiveelectrocardiogram than single coronary artery.4. The baseline plasma ET-1concentrations of thepatients with CSF were higher than control subjects, the difference was not significant（25.11±6.85pg/ml vs21.55±5.98pg/ml, P>0.05）,and this difference increased after Dobutaminestress test（37.60±6.93pg/ml vs14.16±5.73pg/ml,P<0.01）.The baseline serum NO concentrations ofthe patients with CSF were lower than control subjects （42.36±9.72μmol/L vs 50.39±9.77μmol/L， P<0.05）. The serum NO concentrations of the patients with CSFsignificantly reduced after Dobutamine stress test （24.88±9.28μmol/L，P<0.01）,but the controlsubjects increased（61.06±8.20umol/L， P<0.01）. Conclusions1. Coronary slow flowphenomenon may lead to myocardial perfusion abnormalities and true myocardial ischemia.2.there is a relationship between coronary slow flow and positive electrocardiogram stress test.3.The patients with CSF exist ET-1and NO imbalance at rest and after Dobutamine stess test,especially after Dobutamine stess test. The results of this study show that vascular endothelialfunction were abnormal of the coronary slow flow patients. |
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