Background Adenosine cardiac stress is widely used as an alternative to exe
rcise testing during myocardial perfusion imaging (MPI). Dyspnea often acco
mpanies the adenosine stress test. Although known asthmatic patients are ex
cluded from this test because of the danger of bronchospasm, there is incom
plete information regarding the role of factors such as chronic obstructive
pulmonary disease (COPD) and tobacco smoking in adenosine-induced dyspnea.
Patients and Methods A total of 122 consecutive patients (75 male, 47 femal
e; mean age 59 years, SD 10 years) undergoing pharmacologic stress testing
with an intravenous infusion of adenosine also had volume-flow spirometry (
Vitalograph Compact, Vitalograph Ltd) before, during, and after the test. T
he indices assessed were forced expiratory volume in one second, its ratio
to the forced vital capacity, and peak expiratory flow rate.
Results Mild io severe symptoms were experienced by 81% of patients during
adenosine infusion. More than half the patients had dyspnea, but there was
no associated bronchospasm. Although the patients with COPD showed paramete
rs indicative of bronchial resistance compared with those without this prob
lem, there was no further deterioration after adenosine infusion. Similarly
, patients with a history of tobacco abuse, despite showing a tendency towa
rd increasing airways resistance, had no bronchospasm during the administra
tion of adenosine.
Conclusions (1) Although dyspnea is a common problem during adenosine stres
s MPI, it is not associated with any appreciable bronchospasm. (2) COPD and
tobacco abuse do not appear to be contraindications to adenosine stress MP
I studies. However, ii is probably safe to exclude patients with severe COP
D from adenosine stress MPI until after further evaluation with larger numb
ers of patients.