Randomized Angioplasty Beta Blocker Intracoronary Trial II - RABBIT II – Presented at AHA 2006
The goal of the trial was to evaluate the use of intracoronary (IC) administration of the beta-blocker propranolol among patients undergoing percutaneous coronary intervention (PCI) also treated with glycoprotein (GP) IIb/IIIa inhibitors.
Patients Enrolled: 400
Mean Follow Up: 1 year (30 days reported to date)
Mean Patient Age: Mean age, 59 years
Elective or urgent PCI
MI within 24 hours of procedure, cardiogenic shock, New York Heart Association class III or IV heart failure, severe renal failure, second planned intervention within 30 days, or allergy to propranolol
Post-PCI MI; composite of death, MI, or ischemic driven target lesion revascularization (TLR) at 30 days
Composite of death, MI, or ischemic driven TVR at 1 year
Patients at a single center undergoing PCI were randomized to IC administration of the beta-blocker propranolol (n = 200) or saline (n = 200). All patients were also treated with GP IIb/IIIa inhibitors.
Baseline characteristics were similar between treatment groups. Heart rate and blood pressure did not change after IC injection of propranolol or placebo.
The primary endpoint of postprocedure myocardial infarction (MI) (creatine kinase-myocardial band elevation) occurred less frequently in the propranolol arm than in the placebo arm (12.5% vs. 21.5%, p = 0.016). The co-primary composite endpoint of 30-day death, postprocedural MI, clinical MI, or ischemic driven target lesion revascularization (TLR) was lower in the propranolol arm (13.5% vs. 22.5%, p = 0.01), driven by the reduction in postprocedure MI. There were no deaths in either arm, and no differences in clinical MI (2.5% for propranolol vs. 1.0% for placebo) or TLR (1.0% for propranolol vs. 1.5% for placebo).
Results were similar across a variety of subgroups, including among those on oral beta-blockers at baseline. The reduction in post-PCI MI occurred only in patients without mechanical complications during the PCI; in the small cohort with patients who had mechanical complications, there was no difference between the treatment groups.
Among patients undergoing PCI also treated with GP IIb/IIIa inhibitors, IC administration of the beta-blocker propranolol was associated with a reduction in the frequency of post-PCI MI compared with IC saline administration.
Results of the present study are very similar to those of an earlier study by the same group that was conducted without mandatory administration of GP IIb/IIIa inhibitors. The results were most successful in patients without mechanical complications during the PCI. Larger, multicenter trials of this low-cost, promising therapy are warranted to confirm the findings beyond this single center, as well as to evaluate clinical outcomes.
Presented by Dr. Barry F. Uretsky at the American Heart Association Annual Scientific Sessions, Chicago, IL, November 2006.
Keywords: Myocardial Infarction, Creatine Kinase, Propranolol, Blood Pressure, Heart Rate, Angioplasty, Balloon, Coronary, Platelet Membrane Glycoprotein IIb, Platelet Glycoprotein GPIIb-IIIa Complex
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