Technetium-99m sestamibi imaging to predict left ventricular ejection fraction outcome after revascularisation in patients with chronic coronary artery disease and left ventricular dysfunction: comparison between baseline and nitrate-enhanced imaging

Abstract

Acceptance of technetium-99m sestamibi as a tracer of myocardial viability is growing, particularly when nitrate-enhanced imaging is used. However, few data are available on the ability of 99mTc-sestamibi to predict the evolution of global left ventricular ejection fraction (EF). The aim of this study was to examine the ability of resting and nitrate 99mTc-sestamibi single-photon emission tomography (SPET) to predict EF changes after revascularisation in patients who have chronic coronary artery disease with left ventricular dysfunction. Using baseline resting and nitrate 99mTc-sestamibi SPET, we studied 61 patients scheduled for revascularisation because of left ventricular dysfunction. EF was estimated using two-dimensional echocardiography before and after the intervention. A post-revascularisation improvement of > or =5 EF units was defined as significant. Using a 13-segment model, 99mTc-sestamibi activity was quantified and the nitrate-induced activity changes calculated. Three different criteria for detecting viability (defined as post-revascularisation reversible dysfunction) in asynergic segments were compared: (1) resting 99mTc-sestamibi activity > or =60%; (2) nitrate 99mTc-sestamibi activity > or =65%; and (3) nitrate-induced increase >+10% or nitrate-induced increase < or =+10% and nitrate activity > or =65%. EF increased significantly in 32 patients. The number of viable asynergic segments was significantly higher in these patients than in the remaining 29 subjects, and the difference was greater (P<0.0002) using definition (3) than using either baseline (P<0.002) or nitrate activity (P<0.0005). There was a significant relationship between EF changes and number of viable asynergic segments: Spearman R=0.38, P<0.005 using baseline; Spearman R=0.39, P<0.002 using nitrate activity; and Spearman R=0.55, P<0.000005 using definition (3). According to receiver operating characteristic (ROC) curve analysis, this last criterion achieved the best results (81% sensitivity, 69% specificity and 75% accuracy), with an area under the ROC curve of 0.838; this area was significantly larger than when using either baseline (0.744, P<0.02) or nitrate activity (0.747, P<0.005). 99mTc-sestamibi SPET appears able to predict the evolution of global left ventricular EF after revascularisation, thereby confirming the value of 99mTc-sestamibi as a tracer of myocardial viability. The combination of baseline resting and nitrate imaging seems to significantly improve the diagnostic accuracy of 99mTc-sestamibi SPET for this particular purpose.

Single Photon Emission Computed Tomography (SPECT) Myocardial Perfusion Imaging Guidelines: Instrumentation, Acquisition, Processing, and Interpretation

“…Myocardial viability can be determined using SPECT ( 99m Tc and 39 In addition, evaluation of stress perfusion (ischemia implies viability), nitrate enhanced perfusion, 139 inotropic contractile reserve with changes in regional/global function with low-dose dobutamine 140 are important adjuncts to enhance the detection of myocardial viability. When available myocardial metabolic imaging with 18 F-FDG is a more sensitive means to detect viability.…”

“…Redistribution of 201 Tl on 4-hour and 24-hour redistribution images in myocardial segments with severely reduced tracer uptake on rest 201 Tl images indicates viability. 143 Hypoperfused myocardial segments with unequivocal improvement following nitrate administration 139 or contractile reserve on low-dose dobutamine 140 are viable. When performing 201 Tl stress-redistribution-reinjection protocols or 99m Tc MPI protocols, it is encouraged to administer 0.4 to 0.8 mg sublingual nitroglycerin prior to reinjection to optimize identification of ischemic viable myocardium.…”

Usefulness of dobutamine Tc-99m sestamibi-gated single-photon emission computed tomography for prediction of left ventricular ejection fraction outcome after coronary revascularization for ischemic cardiomyopathy

“…The mean number of viable asynergic segments was higher in group A than in group B (Table 2). With use of a threshold of Ͼ4 viable segments to identify patients with LV ejection fraction increase Ն5 U, 15 sestamibi activity achieved 89% sensitivity, 67% specificity, and 78% accuracy. Dobutamine-gated SPECT: During dobutamine there was a marked variation (from -3 to ϩ19 ejection fraction units) of the LV ejection fraction with respect to baseline values.…”

“…13 Significant improvement in global LV ejection fraction after revascularization was defined as an increase of Ն5 ejection fraction units in the follow-up control compared with the baseline value. 14,15 Statistical analysis: Results are expressed as mean Ϯ SD. The comparison of variables within and between groups was performed with the Student's t test for paired or independent samples as appropriate.…”

Predicting revascularization outcome in patients with coronary artery disease and left ventricular dysfunction (data from the SEMINATOR study)

“…5,8 -11,15,16 The criteria used to define the presence of myocardial viability have been demonstrated to be the most accurate, but a simplified approach based on the sole assessment of nitrateenhanced uptake could probably be equally effective. 17 Finally, it cannot be excluded that a larger number of patients would have shown LV functional recovery if the follow-up control had been delayed, 22 although the interval of 3 months has been widely used in reports on viability. …”