Author + information
- Received December 29, 1994
- Revision received May 26, 1995
- Accepted May 30, 1995
- Published online November 1, 1995.
- Hosen Kiat, MD, FRACP, FACCa,*,
- Abdulmassih S. Iskandrian, MD, FACCa,*,
- Bernard J. Villegas, MD, FACCa,†,
- Mark R. Starling, MD, FACCa,‡,
- Daniel S. Berman, MD, FACCa,a,
- for the International Arbutamine Study Groupa
- ↵*Address for correspondence:Dr. Hosen Kiat, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Room A042, Los Angeles, California 90048.
Objectives. This study sought to evaluate the efficacy and safety of arbutamine when used in conjunction with thallium-201 single-photon emission computed tomography (SPECT) in a multicenter trial and to compare arbutamine stress and treadmill exercise thallium-201 SPECT for diagnostic sensitivity and myocardial perfusion pattern.
Background. Arbutamine is a potent beta-agonist developed specifically for pharmacologic stress testing.
Methods. Arbutamine was administered by a novel computerized closed-loop device that measures heart rate and adjusts arbutamine infusion to achieve a selected rate of heart rate increase toward a predetermined limit. The cohort included 184 patients who underwent arbutamine stress testing, of whom 122 (catheterization group) had angiographically defined coronary artery disease (≥50% diameter stenosis of a major coronary artery), and 62 had a low pretest likelihood of coronary artery disease (low likelihood group). A subset of 69 patients from the catheterization group underwent both arbutamine and exercise stress testing.
Results. Hemodynamic responses during arbutamine and exercise stress testing demonstrated no significant difference in percent increase in heart rate (81% vs. 76%) or systolic blood pressure (26% vs. 30%). The sensitivity for detecting coronary artery disease (≥50% stenosis) using arbutamine thallium-201 SPECT was 87% (95% for detecting ≥70% stenoses), and the normalcy rate in the low likelihood group was 90%. In patients completing both arbutamine and exercise stress testing, thallium-201 SPECT sensitivity for detecting coronary artery disease (≥50% stenosis) was 94% and 97% (p = NS), respectively. Furthermore, SPECT segmental visual score agreement (defect vs. no defect) showed a concordance of 92% between arbutamine and exercise results (kappa 0.80, p < 0.001). The stress thallium-201 SPECT segmental scores showed 83% exact agreement (kappa 0.69, p < 0.001), and analysis of the reversibility of segments with stress perfusion defects demonstrated 86% exact agreement (kappa 0.68, p < 0.001). In general, side effects associated with arbutamine were well tolerated and resolved with discontinuation of infusion.
Conclusions. Arbutamine, administered by a closed-loop feedback system was shown to be a safe and effective pharmacologic stress agent. Arbutamine stress thallium-201 SPECT appears to be accurate for the diagnosis of coronary artery disease with a diagnostic efficacy similar to that of treadmill exercise thallium-201 studies.
This study was supported in part by Gensia, Inc., San Diego, California. It was presented in part at the 43rd Annual Scientific Session of the American College of Cardiology, Atlanta, Georgia, March 1994. A list of participating investigators and clinical sites for the International Arbutamine Study Group appears in reference 45.
- Received December 29, 1994.
- Revision received May 26, 1995.
- Accepted May 30, 1995.
- American College of Cardiology