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Comparison of 3- versus 6-minute infusions of adenosine in thallium-201 myocardial perfusion imaging
B J Villegas1, R C Hendel, S T Dahlberg
1Myocardial Isotope Research Laboratory, University of Massachusetts Medical Center, Worcester 01655.
Insights
A shorter adenosine infusion (3 minutes) during stress testing reduces side effects without compromising diagnostic accuracy for coronary artery disease detection. This finding optimizes patient comfort and test efficacy.
Area of Science:
- Cardiology
- Nuclear Medicine
- Pharmacology
Background:
- Adenosine thallium stress testing is valuable for diagnosing coronary artery disease.
- Optimal adenosine dosage for diagnostic efficacy and minimal side effects requires evaluation.
Purpose of the Study:
- To compare the diagnostic efficacy and side effect profiles of 3-minute versus 6-minute adenosine infusions in stress testing.
- To determine the impact of infusion duration on hemodynamic changes, arrhythmias, and image analysis.
Main Methods:
- A randomized trial involving 11 subjects comparing 3-minute and 6-minute adenosine infusions (140 mcg/kg/min).
- Assessment of side effects, hemodynamic parameters, and occurrence of dysrhythmias.
- Analysis of segmental agreement and delayed scan agreement between stress images.
Main Results:
- The 6-minute infusion protocol resulted in significantly more side effects (p < 0.05).
- No significant differences in hemodynamic changes or dysrhythmia occurrence were observed between infusion durations.
- High agreement was found for segmental stress images (89%) and delayed scans (79%).
- A higher incidence of redistribution was noted after the 6-minute infusion (p = 0.014).
Conclusions:
- A 3-minute adenosine infusion is effective for diagnosing coronary artery disease, with fewer side effects than a 6-minute infusion.
- Diagnostic results can be achieved even if a 6-minute infusion is stopped early (after 2-3 minutes) due to side effects.
- Early discontinuation of a 6-minute infusion may lead to underestimation of viable myocardium.
Abstract:
Adenosine thallium stress testing has a demonstrated utility in the detection of coronary artery disease. The optimal dose for diagnostic efficacy with minimal side effects has not been critically evaluated. A randomized 3- and 6-minute infusion of adenosine (140 micrograms/kg/min) was performed in 11 subjects. Subjects reported more side effects during the 6-minute infusion protocol (p < 0.05). Hemodynamic changes were not different during either infusion duration. All dysrhythmias began within 2 minutes and therefore the duration of the infusion did not influence their occurrence. Segmental comparison of the stress images demonstrated an 89% agreement. Delayed scans demonstrated a 79% agreement. There was a higher incidence of redistribution following the 6-minute infusion (p = 0.014). We conclude that when side effects necessitate the discontinuation of a 6-minute adenosine infusion, a diagnostic test can still be achieved if 2 to 3 minutes of adenosine have been administered before the thallium injection; however, the amount of viable myocardium may be underestimated.