The impact of adjunctive adenosine infusion during exercise myocardial perfusion imaging: Results of the Both Exercise and Adenosine Stress Test (BEAST) trial.

BACKGROUND: Failure to achieve an adequate heart rate limits the sensitivity of exercise myocardial perfusion imaging (MPI) for the detection of coronary artery disease. In addition, it is often not possible to discontinue medications that may blunt the heart rate response to exercise, because of conditions such as hypertension or angina. However, if pharmacologic stress testing is performed, the ability to assess functional capacity is lost. Accordingly, we developed a protocol that incorporates adenosine stress with symptom-limited exercise. METHODS AND RESULTS: As part of a multicenter study, 35 patients were enrolled prospectively and underwent both exercise MPI and exercise MPI with a 4-minute adenosine infusion on a separate day. Technetium 99m sestamibi was injected at or near peak exercise (exercise only) and at 2 minutes into the adenosine infusion (combined exercise and adenosine). The perfusion images were interpreted in a blinded fashion. The combined adenosine and exercise protocol was well tolerated. The summed stress scores and summed difference scores were greater in the exercise-plus-adenosine group than in the exercise-only group (10.0 vs 8.5, P =.02, and 4.9 vs 3.3, P =.002, respectively). Exercise time was slightly but significantly less with the exercise-plus-adenosine protocol (8 minutes 46 seconds vs 8 minutes 11 seconds, P =.027). CONCLUSION: A protocol combining 4 minutes of adenosine infusion with symptom-limited exercise was safe and well tolerated. Furthermore, this protocol resulted in a greater amount of myocardial ischemia detected on MPI while allowing for the assessment of functional capacity. A combined exercise and adenosine protocol may be a useful test for patients undergoing MPI who are unlikely to achieve an adequate chronotropic response.

Randomized double-blind safety study of enoxaparin versus unfractionated heparin in patients with non-ST-segment elevation acute coronary syndromes treated with tirofiban and aspirin: the ACUTE II study. The Antithrombotic Combination Using Tirofiban and Enoxaparin.

BACKGROUND: In comparison with treatment with unfractionated heparin (UFH) and aspirin (ASA), both tirofiban administered with UFH and ASA, and enoxaparin plus ASA have shown superiority in reducing cardiac ischemic events in patients with unstable angina and non-ST-segment elevation myocardial infarction. Replacing UFH with enoxaparin when tirofiban is administered to patients may offer further therapeutic benefit, but could also increase bleeding. OBJECTIVE: Our objective was to provide estimates of the frequency of bleeding complications, as defined by means of the Thrombolysis In Myocardial Infarction(TIMI) group, and collect data on clinical efficacy of the combination of tirofiban with enoxaparin plus ASA. METHODS: Five hundred twenty-five patients with UA/NSTEMI were treated with tirofiban coadministered with ASA and randomized to receive either UFH (n = 210) or enoxaparin (n = 315). Therapy was administered for 24 to 96 hours. Bleeding incidences were assessed until 24 hours after trial therapy was discontinued; other clinical outcomes were assessed for as long as 30 days. RESULTS: The total bleeding rate (TIMI major + minor + loss-no-site) for the UFH group versus the enoxaparin group was 4.8% vs 3.5% (odds ratio [OR] 1.4, CI 0.6-3.4). The TIMI major and minor bleeding rates for the UFH versus the enoxaparin groups were 1.0% versus 0.3% (OR 3.0, CI 0.3-33.8) and 4.3% versus 2.5% (OR 1.7, CI 0.7-4.6). There was an increase in nuisance cutaneous and oral bleeds (<50 mL of blood loss) in the enoxaparin group. Death or myocardial infarction occurred with similar frequency in the 2 groups (9.0% vs 9.2%). However, refractory ischemia requiring urgent revascularization and rehospitalization because of unstable angina occurred more frequently in the UFH group (4.3% vs 0.6% and 7.1% vs 1.6%, respectively). CONCLUSIONS: Combination therapy with tirofiban plus enoxaparin appears safe, relative to therapy with tirofiban plus UFH.