RT Journal Article
SR Electronic
T1 Effect of Caffeine Intake on Myocardial Hyperemic Flow Induced by Adenosine Triphosphate and Dipyridamole
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 730
OP 738
VO 45
IS 5
A1 Shigeto Kubo
A1 Eiji Tadamura
A1 Hiroshi Toyoda
A1 Marcelo Mamede
A1 Masaki Yamamuro
A1 Yasuhiro Magata
A1 Takahiro Mukai
A1 Haruhiro Kitano
A1 Nagara Tamaki
A1 Junji Konishi
YR 2004
UL http://jnm.snmjournals.org/content/45/5/730.abstract
AB The aims of this study were (a) to compare absolute myocardial blood flow (MBF) during adenosine triphosphate (ATP) infusion with that after dipyridamole administration without caffeine intake and (b) to evaluate the effect of caffeine intake on the hyperemic flow induced by these coronary vasodilator agents. Methods: MBF was quantified with 15O-labeled water and PET at rest, during ATP infusion (0.16 mg/kg/min for 9 min), and after dipyridamole administration (0.56 mg/kg over 4 min) after a 24-h abstinence from caffeine (baseline evaluation) in 10 healthy volunteers. Within 2 wk, the same PET studies were repeated after caffeine intake to evaluate the effect of caffeine on the hyperemic flow induced by these pharmacologic agents (caffeine study). Myocardial flow reserve (MFR), defined as the ratio of hyperemic to resting blood flow, was also evaluated. Results: Resting MBF in baseline and caffeine studies did not differ significantly (0.79 ± 0.29 vs. 0.75 ± 0.31 mL/min/g, P = 0.88). Without caffeine intake, MBF during ATP infusion was significantly higher than that after dipyridamole administration (3.70 ± 0.67 vs. 3.00 ± 0.79 mL/min/g, P = 0.003), whereas there was no significant difference in MFR between ATP and dipyridamole stress (5.15 ± 1.64 vs. 4.11 ± 1.44, P = 0.07). After caffeine intake, the hyperemic flows induced by ATP and dipyridamole were not significantly different (1.68 ± 0.37 vs. 1.52 ± 0.40 mL/min/g, P = 0.50). MFR estimated by ATP and dipyridamole also did not differ significantly in the caffeine studies (2.44 ± 0.88 vs. 2.25 ± 0.94, P = 0.73). MBF during ATP infusion and after dipyridamole administration were significantly lower in the caffeine studies than that in the baseline evaluation (1.68 ± 0.37 vs. 3.70 ± 0.67 mL/min/g, P < 0.0001, and 1.52 ± 0.40 vs. 3.00 ± 0.79 mL/min/g, P < 0.0001, respectively). Conclusion: This study demonstrates that ATP has the potential to induce greater hyperemia than dipyridamole, whereas hyperemic responses to ATP and dipyridamole are similarly attenuated after caffeine intake. These findings suggest that abstinence from caffeine before ATP stress testing may be needed.