Rest technetium-99m sestamibi tomography in combination with short-term administration of nitrates: feasibility and reliability for prediction of postrevascularization outcome of asynergic territories.
OBJECTIVE
This study investigated the role of nitrate technetium-99m sestamibi imaging in predicting the postrevascularization outcome of chronically hypoperfused asynergic territories.


BACKGROUND
Rest technetium-99m sestamibi myocardial scintigraphy underestimates the presence of viable myocardium in asynergic territories. Stimulation that improves coronary blood flow could increase tracer uptake in hibernating territories.


METHODS
Nineteen patients with a previous myocardial infarction and left ventricular dysfunction scheduled for revascularization underwent quantitative technetium-99m sestamibi tomography under baseline conditions and during isosorbide dinitrate infusion. Global and regional function were assessed, respectively, before and after revascularization by radionuclide angiocardiography and two-dimensional echocardiography.


RESULTS
Seven patients (group A) showed postrevascularization regional function recovery, and 12 (group B) showed no significant changes. In group A, nitrate infusion induced a decrease in the extent of the global uptake defect ([mean +/- SD] -37.4 +/- 21.6% of baseline value); in group B, no change or a slight increase was observed (+5.8 +/- 8.4%, p < 0.0005 vs. group A). The nitrate-induced changes in the extent of uptake defect correlated with postrevascularization changes in ejection fraction (r = -0.94, SEE 7.6). After revascularization, 11 asynergic vascular territories showed improvement (hibernating), and 34 remained unchanged (fibrotic). With administration of nitrates, 10 hibernating territories had a decrease in the extent of uptake defect, whereas only 4 of 34 of the fibrotic territories showed a nitrate-induced uptake improvement.


CONCLUSIONS
Short-term administration of isosorbide dinitrate immediately before injection of technetium-99m sestamibi increases tracer uptake in some chronically hypoperfused asynergic territories. This finding correlates with the observation of post-revascularization functional recovery. Nitrate technetium-99m sestamibi myocardial scintigraphy could be a promising method for the noninvasive detection of viable hibernating myocardium.
Bisi
G
G
Department of Clinical Pathophysiology, University of Florence, Italy.
Sciagrà
R
R
Santoro
G M
GM
Fazzini
P F
PF
D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007548:Isosorbide Dinitrate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery; D009204:Myocardial Revascularization; D011237:Predictive Value of Tests; D017256:Technetium Tc 99m Sestamibi; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*; D015646:Ventriculography, First-Pass
D017256:Technetium Tc 99m Sestamibi; D007548:Isosorbide Dinitrate