Mechanism of ST segment depression during exercise tests in patients with liver cirrhosis

Purpose : To our experience, ST segment depression is sometimes detected in an exercise electrocardiogram (ECG) test in patients with liver cirrhosis who have no significant coronary stenosis. In this study, the mechanism of ST segment depression in liver cirrhosis was examined using 99mTc-methoxy-isobutyl-isonitrile (MIBI) myocardial scintigraphy.
Methods : Six patients with liver cirrhosis (LC group), and 15 normal subjects (N group) were examined. To evaluate the level of myocardial blood flow, a Bull’s eye display of myocardial blood flow was performed after dividing the left ventricle into 9 segments. Exercise myocardial scintigraphy with MIBI was performed to obtain the increase in % uptake. Angiographies were performed with a CAG system by inserting a 5 French Judkins catheter via the right femoral artery.
Results : No significant coronary stenosis was found in any of the LC patients. Neither a decrease in MIBI uptake nor defect was observed on Bull’s eye images from the LC group. The mean % uptake increase was 61.0 ± 5.6% in the N group. In the LC group, although neither a decrease in MIBI uptake nor a defect was visually observed on Bull’s eye images obtained during exercise, the % uptake increases (mean : 52.5 ± 5.8%) were lower than those of the N group (p<0.05).
Conclusion : These findings suggest that a disorder in coronary flow reserve occurs in liver cirrhosis patients, because the decreased MIBI uptake during exercise is due to the depression of flow-mediated vasodilatation controlled by the endothelium of the coronary artery and the estrogenic digitalis action of blood flow independency.