IVUS-Guided Balloon Angioplasty References In the Upsize Preliminary Investigation of Local Therapy Using Porous PTCA Balloons and Low Molecular Heparin (PILOT) trial, pre-intervention IVUS was used to guide percutaneous transluminal coronary angioplasty (PTCA) in an attempt to produce stent-like late outcomes but avoid routine stent implantation.[3] The lesion site external elastic membrane (EEM) diameter was measured and discounted by 10% to select the PTCA balloon size. Only flow-limiting dissections (those with TIMI flow grade <3) were stented. Exclusions included severe angulation, total occlusions, vein graft lesions, vessels <2.0 mm by angiography, and acute ischemic syndromes. Three hundred forty-six patients were enrolled. Fifty-five percent of the lesions were in the left anterior descending artery. Although angiographic reference dimensions averaged 2.84 mm, the PTCA balloon size averaged 4.0 mm because the IVUS lesion site EEM dimensions averaged 4.67 mm. Dissections were common (64% by angiography and 73% by IVUS), but stent and glycoprotein IIb/IIIa use was infrequent. Acute complications included death (0.9%), Q-wave MI (2.1%), coronary artery bypass grafting (0.6%), and repeat PTCA (0.9%), with some patients having more than 1 complication. At 1 year, 0.9% of patients had died, 2.6% had an MI, and 10% had target lesion restenosis. The rate of freedom from death or MI was 94% and freedom from death, MI, or revascularization was 81%. Seventy-six percent of the patients had angiographic follow-up, and among these patients, the restenosis rate was 21%. Thus, IVUS-guided "adaptive" PTCA allowed safe use of "oversized" balloons (compared with conventional standards), yielding long-term results comparable to those of stenting. Dissections do not have to be treated unless they are flow-limiting.