| Objective: Percutaneous coronary intervention(PCI) of ostial lesions is complex and is technically very demanding. The cardiac adverse events accurance of ostial lesions is higher compared with non-ostial lesions during and after PCI. Previous study indicates that inaccurate stent deployment and inadequate stent expansion were the two main factors affect the prognosis of coronary ostial lesions. Currently, IVUS is considered as the gold standard guiding PCI of ostial lesions. However, it is limited in the clinical applications to a great extent. Stent Boost Subtract is a new developed interventional imaging technique which can not only enhance the stent visuality to judge the stent expansion, but also reveal the relationship between stent and vessel walls. Therefore, SBS can theoretically assist in guiding accurate stent deployment and identifying inadequate stent expansion during PCI of coronary ostial lesions. However, there is no special study report about the application of SBS in the PCI of coronary ostial lesions yet. The purpose of this study was to evaluate the usefulness of SBS in the intervention of coronary ostial lesions when regarding IVUS as the gold standard of accurate stent deployment and adequate stent expansion.Methods: This single-centre retrospective study analysed 55 patients confirmed with inclusion crireria who underwent ostial lesion angioplasty with the use of both SBS and IVUS before and after stent deployment from March 2012 to Dec 2014. Inclusion criteria were patients with indications of PCI of denovo coronary ostial lesions defined as a lesion occurring within 3 mm of the ostium of a native aorto-ostial(i.e. left main or right coronary arteries) or major coronary vessel(left anterior descending, left circumflex, and ramus intermedius arteries) without any extension proximally or distally into an adjacent branch vessel and clinical indication for PCI with stent implantation(figure 2). Exclusion criteria included:(1)age <18 years or >80 years;(2) bifurcation lesions involved more than 1 ostial lesion;(3)left main coronary artery with length less than 8mm or diameter greater than 5mm;(4)cross-over technique;(5)coronary artery bypass grafts ostial lesions;(6)lesions of chronic total occlusion;(7)no checking of SBS/IVUS before and/or after stent deployment;(8)poor image that affect results analysis;(9)coronary artery bypass grafting(CABG) after coronary angiography(CAG);(10) complications like no re-flow, slow flow or dissection during PCI;(11) contraindication for PCI or no PCI. We defined the SBS and IVUS criteria for accuracy of stent location and adequate stent deployment. The criteria for accuracy of stent location for SBS and IVUS was defined as the stent being deployed<1 mm proximal or distal to the true ostium. Minimum stent area(MSA)of SBS was calculated from minimum stent diameter by supposing it to be a round. MSA of IVUS was measured automatically. The criteria for adequate stent expansion of SBS was defined as :(1)no sign of focal inadequate expansion, no protrusion of the stent strut and no disappearance of continuity of stent struts.(2)stent minimum diameter>70% of reference diameter.(3)stent minimum diameter>2.0 mm. The criteria for adequate stent expansion of IVUS was defined as:(1)MSA at least≥5.0 mm2 if the reference vessel was≥2.8 mm, MSA at least≥4.5 mm2, if the reference vessel was<2.8 mm.(2)Symmetric index(minimum stent diameter/maximum stent diameter) ≥0.7.(3)lack of major dissections, intra-mural hematomas, and geographic misses.Percutaneous coronary intervention was completed according to standard guidelines by experts with extensive experiences of cardiac intervention diagnosis and treatment. SBS and IVUS were performed before and after stent deployment. We added high-pressure dilatation or additional stents based on the results of IVUS.Coronary angiography was performed using Allura Xper FD10 or FD20(Philips Healthcare, Best, The Netherlands). Prior angiographic data were retrieved from PCI database of our catheter center. Prior angiographic data was performed using automated edge-detection software(QAngio XA version 7.2, Medis Medical Imaging System, Netherlands). We analysed diameter stenosis, minimum lumen diameter(MLD), lesion length and reference diameter.SBS was performed using Allura Xper FD10 or FD20(Philips Healthcare, Best, The Netherlands)equipped with SBS analysis system. SBS images were analyzed using Image Analysis System. Minimum stent diameter(MSD) and reference stent diameter(stent edge diameter) were calculated automatically by SBS software.IVUS examination system consists of intravascular ultrasound catheter, pullback device and IVUS console. IVUS examination was performed using standard PCI technique. Data were stored digitally on DVD for off-line analysis. Prior IVUS data were retrieved from IVUS database of our catheter center. Minimum stent area(MSA) was measured by IVUS examination system as well as the accuracy of stent deployment.Statistical analysis: SPSS 13.0(SPSS Inc., USA) for windows was used for all analysis. Categorical variables were presented as numbers or percentages. Data are presented as the mean ± SD for continuous variables. Linear regression analysis was performed to evaluate the correlation between SBS-MSA and IVUS-MSA. The SBS resulting sensitivities and specificities, positive predictive value and negative predictive value of stent unexpansion were calculated while IVUS resulting as “gold standard ”. A P value of <0.05(2-sided) was considered statistically significant.Results:(1)According to prior defined criteria for accuracy of stent location by IVUS and SBS, 48(82.8%) lesions were accurate and inaccurate stent deployment in 10/58(17.2%) observations with 6/58(10.3%) too distal(>1mm) to the IVUS and SBS determined ostium and 4/58(6.9%) too proximal(>1mm) to the IVUS and SBS determined ostium.(2)According to prior defined criteria for adequate stent expansion by SBS and IVUS, SBS images showed 50(86.2%) adequate stent expansion and 8(13.8%) inadequate stent expansion. IVUS images showed 48(82.8%) adequate stent expansion and 10/58(17.2%) inadequate stent expansion. SBS predicted inadequate findings of IVUS with 100% specificity, 80% sensitivity, 100% positive predictive value and 96% negative predictive value.(3)A significant positive correlation was observed between SBS-MSA and MSA by IVUS with a regression coefficient of 0.91, P<0.001.Conclusions: As a simple and quick interventional image technology, SBS can not only guide stent positioning during PCI of coronary ostial lesions effectively, but also assist in evaluating stent expansion. |
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