Clinical significance of augmented fluorine-18 deoxyglucose uptake in remote normoperfused myocardium in patients with acute coronary syndrome under fasting conditions.

OBJECTIVES

We evaluated the relation between increased fluorine-18 deoxyglucose (FDG) uptake in remote normoperfused areas and acute ischemic events in patients with ischemic heart disease.

METHODS

We performed nitrogen 13 ammonia (NH3) and FDG positron emission tomography (PET) on 67 patients (46 men, mean age 65 years) with ischemic heart disease (46 with myocardial infarction, 21 with angina pectoris). PET images were analyzed in only remote normoperfused areas (excluding infarct-related areas, areas containing coronary arteries with significant stenosis and/or showing vasoconstriction, and areas showing abnormal left ventricular wall motion).

RESULTS

Seventeen patients (group 1) exhibited increased FDG uptake, as defined by our institution's guidelines, in remote normoperfused areas and 50 (group 2) did not. The plasma glucose levels (90.8+/-10.9 mg/dL vs. 94.9+/-11.8 mg/dL) and the serum insulin levels (7.3+/-2.9 IU/L vs. 8.6+/-3.4 IU/L) did not vary between the 2 groups. The serum free fatty acid levels were lower in group 1 than in group 2 (0.46+/-0.21 mEq/L vs. 0.62+/-0.29 mEq/L; P = .02). Patients were subsequently reclassified into either the acute coronary syndrome (ACS) group (n = 16), which consisted of patients exhibiting subacute myocardial infarction and unstable angina, or the non-ACS group (n = 51). A total of 11 (69%) of 16 ACS group patients but only 6 (12%) of 51 non-ACS group patients were included in group 1 (P<.0001). The serum free fatty acid levels were not different between ACS group and non-ACS group (0.52+/-0.21 mEq/L vs. 0.60+/-0.29 mEq/L; P = .17).

CONCLUSIONS

Our data suggest that increased FDG uptake in remote normoperfused areas is closely related to the acute myocardial ischemia, suggesting that myocardial ischemic events may produce acceleration in glucose utilization even in remote nonischemic myocardium.