Objective: To determine whether adenosine could be safely administered to patients with chronic obstructive pulmonary disease (COPD) for coronary vasodilatation during perfusion scintigraphy without causing bronchospasm. Material and Methods: The study was divided into two phases. In the monitoring phase, patients with COPD were pretreated with an inhaled bronchodilator (albuterol) and had pulmonary function monitored during the infusion of a graduated dose of adenosine. Eligibility for entry into this phase of the study was determined on the basis of results of pulmonary function testing (PFT) during resting. Once we had shown that adenosine could be safely administered to patients with COPD, an implementation phase was begun. Entry did not require resting PFT, and patients were administered adenosine without monitoring of pulmonary function. Differences between patients with normal pulmonary function or mild COPD and those with more severe COPD were analyzed statistically. Results: Of 94 patients entered into the monitoring phase, none had obvious bronchospasm. The dosage of adenosine was reduced in four patients because of a decrease in forced expiratory volume in 1 second (FEV1) of 20% in comparison with baseline (FEV1 before administration of albuterol). The mean FEV1 decreased slightly from 1.83 L after administration of albuterol to 1.78 L during the maximal adenosine dose. Patients with a remote history of asthma, positive result of a methacholine challenge test, or mild COPD (FEV1 60 to 80% of the maximal predicted value for age) did not differ significantly in their response to infusion of adenosine from those with moderate or severe COPD (FEV1 30 to 59% of the maximum predicted for age). Of 117 patients in the implementation phase, 2 had bronchospasm during infusion of adenosine that was quickly terminated by stopping the administration in one patient and reducing the dose of adenosine in the other. Conclusion: This study shows that adenosine can be safely administered intravenously to selected patients with known or suspected COPD to produce coronary vasodilatation for myocardial perfusion imaging. Patients who are within the guidelines established for this study should be considered for adenosine coronary vasodilatation with use of bronchodilator pretreatment, a graduated dose of adenosine, and regular chest auscultation during the infusion.
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