title: The impact of adenosine pharmacologic stress combined with low-level exercise in patients undergoing myocardial perfusion imaging (BIWAKO adenosine-Ex trial).
abstract: BACKGROUND
  The combination of adenosine infusion with low-level exercise has become a common approach for inducing stress during stress myocardial perfusion imaging (MPI). We investigated stress MPI performed by combined low-level exercise and adenosine infusion. This combined protocol can decrease adverse reactions and reduce the effect of scattered rays from the liver.
  
  
  RESULTS
  Subjects were clinically referred for a 53-min rest-stress Tc-99m Sestamibi MPI procedure using BIWAKO PROTOCOL. Ninety-eight patients (44.5%) underwent adenosine infusion with ergometer exercise testing and 122 patients (55.5%) underwent adenosine infusion without exercise testing. We evaluated the liver/heart (L/H) uptake ratio, background activity in the upper mediastinum, and adverse reactions.
  
  
  RESULTS
  The L/H ratio and background activity were lower in the adenosine-exercise group than in the adenosine-non-exercise group (1.8 ± 0.54 vs. 2.1 ± 0.62, P < 0.0056; 43.1 ± 12.2 vs. 61.5 ± 15.4, P < 0.0001). The adenosine-exercise group had fewer adverse reactions than the adenosine-non-exercise group (11.2 vs. 19.7%). All of the adverse reactions were minor, with the exception of severe back pain in one case. The incidence of adverse reactions in our study was lower than that in previous studies for unknown reason.
  
  
  CONCLUSIONS
  Adenosine infusion in combination with low-level exercise seems to result in higher-quality images and fewer adverse reactions than adenosine infusion without exercise. The combined protocol decreases adverse reactions and improves the quality of myocardial perfusion images by decreasing background activity.
authors.affiliation: Department of Radiology, Otsu Red Cross Hospital, 1-35 Nagara, Otsu, Shiga, 520-8511, Japan. hmrky77@u01.gate01.com
authors.forename: Hajime
authors.initials: H
authors.lastname: Monzen
authors.forename: Masatake
authors.initials: M
authors.lastname: Hara
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirata
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Makoto
authors.initials: M
authors.lastname: Ogasawara
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Higuchi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Hisato
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Rumio
authors.initials: R
authors.lastname: Yuki
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Hirose
mesh_terms: D000241:Adenosine / Q000009:adverse effects / Q000494:pharmacology*; D000368:Aged; D015444:Exercise; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D008482:Mediastinum; D055414:Myocardial Perfusion Imaging / Q000009:adverse effects / Q000379:methods*; D009206:Myocardium / Q000378:metabolism; D011786:Quality Control; D012449:Safety; D013312:Stress, Physiological / Q000187:drug effects*
chemical_list: D000241:Adenosine