Document Detail

Effects of adenosine and a selective A2A adenosine receptor agonist on hemodynamic and thallium-201 and technetium-99m-sestaMIBI biodistribution and kinetics.
MedLine Citation:
PMID:  19833310     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: The purpose of this study was to compare a selective A(2A) adenosine receptor agonist (regadenoson) with adenosine in clinically relevant canine models with regard to effects on hemodynamics and thallium-201 ((201)Tl) and technetium-99m ((99m)Tc)-sestaMIBI biodistribution and kinetics. BACKGROUND: The clinical application of vasodilator stress for perfusion imaging requires consideration of the effects of these vasodilating agents on systemic hemodynamics, coronary flow, and radiotracer uptake and clearance kinetics. METHODS: Sequential imaging and arterial blood sampling was performed on control, anesthetized closed-chest canines (n = 7) to evaluate radiotracer biodistribution and kinetics after either a bolus administration of regadenoson (2.5 microg/kg) or 4.5-min infusion of adenosine (280 microg/kg). The effects of regadenoson on coronary flow and myocardial radiotracer uptake were then evaluated in an open-chest canine model of a critical stenosis (n = 7). Results from ex vivo single-photon emission computed tomography were compared with tissue well-counting. RESULTS: The use of regadenoson compared favorably with adenosine in regard to the duration and magnitude of the hemodynamic effects and the effect on (201)Tl and (99m)Tc-sestaMIBI biodistribution and kinetics. The arterial blood clearance half-time was significantly faster for (99m)Tc-sestaMIBI (regadenoson: 1.4 +/- 0.03 min; adenosine: 1.5 +/- 0.08 min) than for (201)Tl (regadenoson: 2.5 +/- 0.16 min, p < 0.01; adenosine: 2.7 +/- 0.04 min, p < 0.01) for both vasodilator stressors. The relative microsphere flow deficit (0.34 +/- 0.02%) during regadenoson stress was significantly greater than the relative perfusion defect with (99m)Tc-sestaMIBI (0.69 +/- 0.03%, p < 0.001) or (201)Tl (0.53 +/- 0.02%, p < 0.001), although (201)Tl tracked the flow deficit within the ischemic region better than (99m)Tc-sestaMIBI. The perfusion defect score was larger with (201)Tl (22 +/- 2.8% left ventricular) than with (99m)Tc-sestaMIBI (17 +/- 1.7% left ventricular, p < 0.05) on ex vivo single-photon emission computed tomography images. CONCLUSIONS: The bolus administration of regadenoson produced a hyperemic response comparable to a standard infusion of adenosine. The biodistribution and clearance of both (201)Tl and (99m)Tc-sestaMIBI during regadenoson were similar to adenosine vasodilation. Ex vivo perfusion images under the most ideal conditions permitted detection of a critical stenosis, although (201)Tl offered significant advantages over (99m)Tc-sestaMIBI for perfusion imaging during regadenoson vasodilator stress.
Choukri Mekkaoui; Farid Jadbabaie; Donald P Dione; David F Meoli; Kailasnath Purushothaman; Luiz Belardinelli; Albert J Sinusas
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  JACC. Cardiovascular imaging     Volume:  2     ISSN:  1876-7591     ISO Abbreviation:  JACC Cardiovasc Imaging     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-10-16     Completed Date:  2010-01-19     Revised Date:  2010-04-12    
Medline Journal Info:
Nlm Unique ID:  101467978     Medline TA:  JACC Cardiovasc Imaging     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1198-208     Citation Subset:  IM    
Division of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8017, USA.
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MeSH Terms
Acute Disease
Adenosine / administration & dosage,  diagnostic use,  pharmacology*
Blood Flow Velocity / drug effects
Chronic Disease
Coronary Circulation / drug effects*
Coronary Stenosis / metabolism,  physiopathology,  radionuclide imaging*
Disease Models, Animal
Hyperemia / physiopathology,  radionuclide imaging
Infusions, Intravenous
Injections, Intravenous
Metabolic Clearance Rate
Myocardial Perfusion Imaging / methods*
Myocardium / metabolism,  pathology
Predictive Value of Tests
Purines / administration & dosage,  diagnostic use,  pharmacology*
Pyrazoles / administration & dosage,  diagnostic use,  pharmacology*
Radiopharmaceuticals / blood,  diagnostic use,  pharmacokinetics*
Receptor, Adenosine A2A / agonists*,  metabolism
Technetium Tc 99m Sestamibi / blood,  diagnostic use,  pharmacokinetics*
Thallium Radioisotopes / blood,  diagnostic use,  pharmacokinetics*
Tissue Distribution
Tomography, Emission-Computed, Single-Photon*
Vasodilator Agents / administration & dosage,  diagnostic use,  pharmacology*
Reg. No./Substance:
0/Purines; 0/Pyrazoles; 0/Radiopharmaceuticals; 0/Receptor, Adenosine A2A; 0/Thallium Radioisotopes; 0/Vasodilator Agents; 0/regadenoson; 109581-73-9/Technetium Tc 99m Sestamibi; 58-61-7/Adenosine
Comment In:
JACC Cardiovasc Imaging. 2009 Oct;2(10):1209-12   [PMID:  19833311 ]

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