Determining appropriate small vessels for stenting by intravascular ultrasound.

To re-evaluate outcomes of stenting in small vessels, we studied 176 patients successfully treated with several types of stent by way of intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA). These lesions were divided into 3 subgroups according to reference diameter (RD) by QCA, and vessel diameter (VD) by IVUS (group I: pre-RD 2.5 mm; group II: pre-RD < 2.5 mm and pre-VD 4.0 mm; group III: pre-RD < 2.5 mm and pre-VD < 4.0 mm). Post-procedure percent diameter stenosis (4 +/- 3%), post-procedure percent plaque area (42 +/- 3%), and loss index (39 +/- 11%) in group II were not significantly different from those in group I (7 +/- 2%, 37 +/- 2%, 45 +/- 5%, respectively). The rates of restenosis and target lesion revascularization in group II (24.0% and 16.0%, respectively) were not different from those in group I (25.9% and 21. 2%, respectively), and were significantly favorable compared to group III (66.7% and 39.4%, respectively; p < 0.05). By the use of IVUS, we not only identified those vessels which would normally go unstented when only using QCA, but also documented excellent long-term outcome in these patients.