Clinical results of three-time-balloon-inflation method performed in elective PCI cases

Percutaneous coronary intervention (PCI) for ischemic heart disease became a common therapy. The improvement of treatment results was caused by invention of drug-eluting stent (DES) but its implantation procedure for pressure and inflation time has not been discussed. 3-time-balloon-inflation method is proved to be an effective method for inflation in in vitro experiments and it was practiced in the clinical field. The purpose of this study is to determine the effectiveness of the 3-time-balloon-inflation method and investigate the factors that cause suppression of stent expansion. From January 2011 to March 2012,PCI with drug-eluting stent (XIENCE V) were performed to 169 patients by a single-operator with 3-time-ballon-inflation method. Minimal lumen area (MLA), vessel cross-sectional area, and plaque cross-section in the MLA were measured by intravascular ultrasound (IVUS) before stent implantation. Minimum stent area (MSA) was measured after stent implantation. Stent expansion ratio (SER) was calculated from assumed area and MSA. Area acquisition ratio (AAR) was calculated from MSA and MLA. Subsequently, the ratio of calcification in the lesion was measured using the color mapping function mounted on the IVUS. The stent diameter used in this study was 2.89±0.35[mm](mean±SD), stent length was 20.5±6.2[mm] (mean±SD), and the stent expansion pressure was 10.3±2.4[atm] (mean±SD). There was no difference in SER by stent size, target vessels, and MLA. Significant difference was seen in the calcification ratio between the group without pre-dilatation (n=27) and the group with pre-dilatation (n=142), but no difference in SER between the two groups. It was suggested that calcification ratio is one of the factors that causes the suppression of stent expansion because significance of calcification ratio came out in AAR.