The angiographic step-up and step-down: a surrogate for optimal stent expansion by intravascular ultrasound

Standard high-pressure stent implantation frequently results in suboptimal stent expansion by intravascular ultrasound (IVUS) criteria. We aim to show that routine expansion of the stent to a diameter greater than the reference segment, leading to an angiographic step-up at the proximal stent edge and step-down at the distal stent edge, results in improved stent expansion.

We studied 25 patients undergoing coronary stent implantation. Twelve patients were randomized to standard sizing and 13 patients to step-up and step-down sizing as the angiographic goal. IVUS was then performed on all patients to detect incomplete stent strut apposition, dissection within the stent or a suboptimal stent expansion index (SEI). SEI was defined as the minimum stent area (MSA)/average reference lumen area x 100. Optimal SEI was defined as greater than or equal to 90% for a MSA less than or equal to 9.0 mm2 and greater than or equal to 80% for a MSA >9.0 mm2.

Four patients (33%) treated with standard stent implantation and 12 patients (92%) treated with the step-up and step-down approach (p = 0.004) achieved optimal stent expansion. No patients in either group had unapposed stent struts or instent dissection on IVUS. There were no major adverse cardiac events on 6-month follow up.

Stent deployment with an angiographic step-up and step-down approach improves the likelihood of optimal stent deployment by IVUS criteria as compared to the standard angiographic endpoint. This stenting technique is a simple and frugal alternative to IVUS-guided percutaneous coronary intervention, achieving very high rates of adequate stent apposition and expansion.