Objective: To determine whether subsets of patients referred for a clinically indicated radionuclide adenosine stress study respond differently to a standard infusion of adenosine. Material and Methods: We assessed multiple clinical and hemodynamic variables in the first 2,000 patients who underwent adenosine perfusion studies in our laboratory. A relevant clinical variable was defined as one that was significantly associated with changes in heart rate and blood pressure during adenosine infusion. Relevant clinical variables that were most significantly related to hemodynamic variables included age, gender, rhythm (atrial fibrillation), diabetes, and left ventricular function. These variables were then related to symptomatic responses (adverse effects) to adenosine infusion. To determine whether the different peripheral responses to adenosine reflected clinically important differences in coronary vasodilatation, we compared perfusion imaging with coronary angiographic findings in the 408 patients who underwent both studies within 6 months of each other. Results: The decrease in systolic b1ood pressure was greater and the reflex tachycardia was less patients 70 years of age or older and in those with insulin-dependent diabetes in comparison with younger patients and those without type 1 diabetes. Men had smaller decreases in blood pressure and smaller increases in heart rate than did women. Patients with atrial fibrillation and those with left ventricular ejection fraction less than 40% had smaller decreases in blood pressure and smaller increases in heart rate than did those in sinus rhythm or those with an ejection fraction of 40% or more. Age 70 years or older, male gender, atrial fibrillation, and left ventricular ejection fraction less than 40% were associated with fewer symptoms and less severe chest pain in comparison with patients without these variables. For patients with coronary angiograms, the relationship between coronary artery disease evident on angiography and perfusion abnormalities noted on scintigraphy was not different for any of the relevant clinical variables. Conclusion: Common clinical patient subsets are associated with different peripheral hemodynamic and symptomatic responses to infusion of adenosine. Despite these observations, however, the ability to detect coronary artery disease with perfusion imaging is not obviously altered.
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