For the interventionalist, proper sizing of coronary stents is critical. While imaging via angiography has been the standard for years, newer intravascular imaging technologies, such as IVUS and OCT, are becoming more widely used, as evidence accrues that these modalities make a difference in outcomes. For example, IVUS (Intravascular Ultrasound) not only allows the measurement of the exact open diameter of the vessel, as seen on angiography, but it shows the “invisible to angiography” layer of plaque. plaque that will be compressed, so that a more accurate post-PCI diameter can be determined. Under-expanded stents have been associated with increased stent thrombosis and restenosis.
The issue then is determining the optimum final diameter of the vessel and choosing the correct size drug-eluting stent to be used in a specific case. You definitely want to pick a size DES that has the ability to be expanded to the optimal diameter.
Dr. Ajay Kirtane of the New York Presbyterian/Columbia University Medical Center recently posted on Twitter a sizing chart that shows the range of nominal sizes and post-dilatation limit sizes for four major drug-eluting stents: the Synergy, Onyx, Sierra, and Elunir . This chart is posted on the wall in all of their cath labs.
We are making available a hi-res image of this chart here – free to download and print out, courtesy of @AjayKirtane and the NYP/CU cath labs, who created it with assistance from the NYC representatives of device manufacturers: Boston Scientific (Synergy), Medtronic (Resolute Onyx), Abbott Vascular (Xience Sierra), and Cordis/Medinol (Elunir).