Changes in Coronary Artery Aneurysms Following Treatment with Abciximab

Background: Previously Etheridge et al reported rapid resolution of large coronary artery aneurysms(CAA) after treatment with abciximab(Abc), an antibody to platelet GP IIb/IIIa receptors. We report our experience with this treatment on 8 pts from Southern California and Arizona. Patients and Methods: These pts either presented with CAA prior to IVIG or developed giant CAA despite IVIG. All pts received a standard recommended dose of Abc: 2.5 mg/kg IV bolus followed by continuous infusion of 0.125 mcg/kg/min for 12 to 24 hrs. Largest CAA diameters were echographically measured in each pt before Abc, and at various time points after Abc. Available coronary angiograms were also reviewed. All pts remained on low-dose aspirin. Platelet aggregation study immediately after Abc showed effective inhibition. Additionally, those pts with CAA greater than 7 mm received warfarin. Results: Average duration of follow-up was 215 days (14 to 351). Initially, 7 pts had aneurysms in right coronary artery (RCA) and 8 pts in LCA. At the end of follow-up greater than 50 % reduction in CAA diameter was noted in only in 1 pt, increase in CAA size in 2 pts and no change in the rest. Intracoronary thrombus was noted in 1 pt before Abc with subsequent resolution. Compared to echo, angiographic CAA measurements were slightly smaller. No CA stenosis or thrombotic occlusion was seen. Conclusions: (1) Abc at current dosage is well tolerated by KS pts. (2) Abc has failed to produce dramatic CAA regression. (3) Abc may prevent thrombotic complications in giant CAA. Speculation: The optimum dose of Abc in KS is unknown, and may be higher than the adult dose in order to counter systemic platelet activation.