Af. Khoury et al., ADENOSINE TL-201 TOMOGRAPHY IN EVALUATION OF GRAFT PATENCY LATE AFTERCORONARY-ARTERY BYPASS GRAFT-SURGERY, Journal of the American College of Cardiology, 29(6), 1997, pp. 1290-1295
Objectives. We sought to ascertain the utility of adenosine thallium-2
01 tomography for assessing graft stenoses late after coronary artery
bypass graft surgery. Background. Although pharmacologic perfusion ima
ging has been increasingly used in the assessment of patients with cor
onary artery disease, the value of this stress modality for detecting
coronary artery bypass graft stenosis late after surgery is unknown. M
ethods. We studied 109 patients who underwent both adenosine thallium
201 tomography and coronary angiography at 6.7 +/- 4.8 (mean +/- SD) y
ears after coronary artery bypass graft surgery. Adenosine thallium-20
1 tomography was assessed quantitatively by computer-generated polar m
aps of the myocardial thallium-201 activity. Results. On coronary angi
ography, significant graft stenoses were present in 68 patients, 65 of
whom had a corresponding perfusion defect as shown by thallium-201 to
mography (sensitivity 96%). Significant stenoses were present in 107 (
37.8%) of 283 grafts. The overall specificity by quantitative tomograp
hy was 61%. Seventy percent of the apparently false positive perfusion
defects could be explained on the basis of unbypassed native disease
or by the presence of fixed defects in patients with previous myocardi
al infarction. Conclusions. Thus, results of adenosine thallium-201 to
mography are nearly always abnormal in patients with late coronary gra
ft stenosis. Most of the false positive defects appear to be due to ei
ther unbypassed native disease or a previous myocardial infarction. (C
) 1997 by the American College of Cardiology.