Scintigraphic assessment of regional cardiac sympathetic nervous system inpatients with single-vessel coronary artery disease

In coronary artery disease, the cardiac sympathetic nervous system is close ly associated with myocardial ischemia. I-123 metaiodobenzylguanidine (MIBG ) imaging allows us to assess the cardiac sympathetic nervous system region ally. One-hundred and eleven patients with single-vessel disease underwent regional quantitative analysis of MIBG imaging before successful percutaneo us transluminal coronary angioplasty (PTCA), and repeat angiography 6 month s after PTCA. Based on the results of the follow-up left ventriculogram, pa tients were divided into 3 groups: 39 angina pectoris (AP), 48 prior myocar dial infarction without asynergy (MI without asynergy) and 24 prior myocard ial infarction with asynergy (MI with asynergy). AP and MI without asynergy had significant correlations between uptake parameters and regional washou t in the territory of diseased vessels, among which the severity score in A P was the most closely correlated with regional washout (r = 0.79, p < 0.00 01). These correlations disappeared in MI with asynergy. To compare regiona l MIBG parameters in the territory of the diseased vessel as well as in the territories of the other major coronary arteries among the 3 groups, we ex amined MIBG parameters in 57 patients with left anterior descending artery (LAD) disease selected from among the study patients. Regional washout in t he territory of the LAD was significantly higher in the MI without asynergy group than in the other two groups. The left circumflex artery (LCX) regio n showed significantly reduced MIBG uptake and an increased extent score in the MI with asynergy group compared with the AP group, although only a dif ference in the extent score existed between the MI with asynergy group and the AP group in the right coronary artery (RCA) region. In addition, the gl obal ejection fraction before PTCA showed a significant negative correlatio n with each regional washout rate. In this way, regional quantitative analy sis of MIBG imaging can detect the regional differences in the cardiac symp athetic nervous system in coronary artery disease, which may be associated with the degree of regional left ventricular dysfunction due to myocardial ischemia.