Product Monograph
Pharmacologic Stress in Myocardial Perfusion Imaging: Adenoscan
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 Imaging Efficacy: Comparisons With Exercise and Angiography
Numerous studies have demonstrated the efficacy of Adenoscan stress imaging compared to exercise stress imaging. In 2 crossover comparative studies that involved 319 subjects who could exercise, images were concordant for the presence of perfusion defects and vascular territories in 85.5% and 93% of cases, respectively. 13 In another study of 175 patients, overall agreement by computer quantification was shown to be similar (86%) between adenosine and exercise stress testing. 14 The study also noted comparability in assessing coronary-specific regional myocardial perfusion, with agreement ranging from 82.7% to 91.4%.
In a blinded comparison study of Adenoscan and exercise thallium-201 images, 98.7% of patients had interpretable results, 8 with excellent:
- concordance with exercise for presence of perfusion defects15
- concordance with exercise based on vascular territories14
Adenoscan also exhibits comparable specificity and sensitivity during thallium-201 single-photon emission computed tomography. 7,16,17 Further support for imaging efficacy is found in 3 separate studies that compared exercise and Adenoscan stress imaging with coronary angiography for the detection of coronary artery disease. 15,18,19
Risk Stratification
Stratifying patients with normal and mildly abnormal scans using Adenoscan stress testing may reduce the number of patients referred to catheterization after nuclear testing (Table 4). 20 Table 4 shows the correlation between worsening scan results and increasing rates of hard events and early catheterization.
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Table 4. Rates of Hard Events* per Year and Rates of Referral to Early Catheterization by Scan Result20 |
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Normal |
Mildly
Abnormal |
Moderately
Abnormal |
Severely
Abnormal |
Hard events (%/year)
(n = 1079) |
1.6% |
3.5% |
5.7% |
10.6% |
Early catheterization (%)
(n = 1159) |
3.8% |
9.7% |
23.1% |
27.2% |
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IMPORTANT SAFETY INFORMATION Intravenous Adenoscan® (adenosine injection) is indicated as an adjunct to thallium-201 myocardial perfusion scintigraphy in patients unable to exercise adequately.
Adenoscan is contraindicated in patients with 2nd- or 3rd-degree AV block, sinus node disease, and known or suspected bronchoconstrictive or bronchospastic lung disease.
Approximately 2.6% and 0.8% of patients developed second- and third-degree AV block, respectively. All episodes of AV block have been asymptomatic, transient, and did not require intervention; less than 1% required termination of adenosine infusion.
Fatal cardiac arrest, sustained ventricular tachycardia (requiring resuscitation), and nonfatal myocardial infarction have been reported coincident with Adenoscan infusion. Patients with unstable angina may be at greater risk.
Side effects that were seen most often included flushing (44%), chest discomfort (40%), and dyspnea (28%). Side effects usually resolve quickly when infusion is terminated and generally do not interfere with test results.
Despite adenosine’s short half-life, 10.6% of the side effects started several hours after the infusion terminated, and 8.4% of the side effects that began during the infusion persisted for up to 24 hours after infusion. In many cases, it is not possible to know whether these late adverse events are the result of Adenoscan infusion. Please see full prescribing information. |
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