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Background: Previously, we examined the difference in stent designs across different sizes for six widely used Drug Eluting Stents (DESs). Although stent post-dilatation to larger diameter is commonly done, typically in the setting of long tapering segment or left-main PCI, there is an increasing recognition that information with regard to the different stent model designs has a critical impact on overexpansion results. This study aims to provide an update on stent model designs for contemporary DES platforms as well as test overexpansion results under with oversized post-dilatation., Methods and Results: We studied 6 different contemporary commercially available DES platforms: Synergy, Xience Xpedition, Ultimaster, Orsiro, Resolute Onyx and Biomatrix Alpha. We investigated for each platform the difference in stent designs across different sizes and results obtained after post-expansion with larger balloon sizes. The stents were deployed at nominal diameter and subsequently over expanded using increasingly large post dilatation balloon sizes (4.0, 5.0 and 6.0mm at 14ATM). Light microscopy was used to measure the changes in stent geometry and lumen diameter after over-expansion. For each respective DES platform, the MLD observed after overexpansion of the largest stent size available with a 6.0mm balloon was 5.7mm for Synergy, 5.6mm for Xience, 5.2mm for Orsiro, 5.8mm for Ultimaster, 5.5mm for 4mm Onyx (5.9mm for the 5mm XL size) and 5.8mm for BioMatrix Chroma., Conclusion: This update presents valuable novel insights that may be helpful for careful selection of stent size for contemporary DES based on model designs. Such information is especially critical in left main bifurcation stenosis treatment where overexpansion to larger oversized diameter may be required to ensure full stent apposition., (Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.)

Background: Peri-stent coronary evaginations may disturb flow and have been proposed as possible risk factor for late stent thrombosis. We describe incidence, predictors, and possible mechanisms of coronary evaginations 12 months after implantation of bioresorbable vascular scaffolds (BVS)., Methods and Results: One hundred and two BVS implanted in 90 patients (age 63 ± 13 years, 71 males, 14 diabetics) were analysed with angiography and optical coherence tomography (OCT) 12 months after implantation. Evaginations were identified as any hollow in the luminal vessel contour between well-apposed struts and were classified as major when extending ≥3 mm with a depth ≥10% of the BVS diameter. Fifty-five (54%) of the BVS (50(56%) of the patients) had at least one evagination (6.1 ± 6.2 evaginations per BVS), with a mean volume of 1.9 ± 1.9 mm(3). Major evaginations were only found in one patient, and in-BVS aneurysms in three patients (4BVS). The presence of evaginations was strongly associated with that of malapposition (P = 0.003) and strut fractures (P = 0.01). No association could be shown between the presence and volume of the evaginations and any clinical variable or the presence of uncovered struts (P > 0.5). Peri-strut low-intensity areas (PSLIA) were present in 29 (53%) of the BVS with evaginations and 12 (26%) of those without (P = 0.0049); their presence was independently associated with the presence, the number (P < 0.003) and volume of the evaginations (P = 0.004) and with that of strut fracture., Conclusions: Optical coherence tomography-detected evaginations are relatively common after BVS implantation, but, as for modern drug-eluting metallic stents, major evaginations are very rare. Optical coherence tomography evidence of immature neointima and strut fractures were associated with more severe development of evaginations., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Objectives: Optical coherence tomography (OCT) was used to investigate integrity and expansion of bioresorbable drug-eluting scaffolds (BVS) after high-pressure postdilation (HPPD)., Background: Because of concerns about the risk of BVS damage, postdilation was not recommended and applied in the existing randomized studies and most registries. Recent real world data suggest incomplete BVS expansion cause higher rates of thrombosis. In vivo confirmation of the safety of high pressure postdilation is of paramount importance., Methods: Data from final OCT examination of consecutive implanted BVS, postdilated with noncompliant (NC) balloons at pressure ≥24 atm were analyzed. The following stent performance indices were assessed with OCT: mean and minimal lumen and scaffold area, residual area stenosis (RAS), incomplete strut apposition (ISA), tissue prolapse, eccentricity index (EI), symmetry index (SI), strut fractures, and edge dissections., Result: Twenty-two BVS postdilated at high pressure were analyzed. The average maximal postdilation balloon inflation (maxPD) was 28 ± 3 atm. High pressure OPN NC Balloon (SIS Medical AG, Winterthur Switzerland) was used in 41% of postdilations with a maximal PD of 30 ± 4.7 atm. Final mean and minimal lumen area were 6.8 ± 1.4 and 5.5 ± 1.4 mm(2) , respectively. OCT showed low percentage of RAS (16 ± 9.6%), and low percentage of ISA (1.8 ± 2.4%). Mean EI was 0.86 ± 0.02 and SI 0.35 ± 0.14. OCT analysis showed one edge dissection and no scaffold fractures., Conclusions: BVS deployment optimization using HPPD does not cause BVS disruption and is associated with a good BVS expansion, low rate of strut malapposition and edge dissections., (© 2015 Wiley Periodicals, Inc.)

Treatment of coronary bifurcation lesions remains an ongoing challenge for interventional cardiologists. Stenting of coronary bifurcations carries higher risk for in-stent restenosis, stent thrombosis, and recurrent clinical events. This review summarizes the current evidence regarding application and use of biomechanical modeling in the study of stent properties, local flow dynamics, and outcomes after percutaneous coronary interventions in bifurcation lesions. Biomechanical modeling of bifurcation stenting involves computational simulations and in vitro bench testing using subject-specific arterial geometries obtained from in vivo imaging. Biomechanical modeling has the potential to optimize stenting strategies and stent design, thereby reducing adverse outcomes. Large-scale clinical studies are needed to establish the translation of pre-clinical findings to the clinical arena., (Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: A strategy of percutaneous bifurcation intervention with provisional bare-metal stent (BMS) implantation followed by drug-eluting balloon (DEB) treatment represents a valuable opportunity in patients not compliant with long-duration dual-antiplatelet therapy. We used optical coherence tomography (OCT) to assess coronary bifurcation lesions treated by BMS and DEB, and secondarily, to better explore the association between stent geometry and tissue coverage., Methods: Twelve patients underwent frequency-domain OCT 6 months after undergoing percutaneous bifurcation intervention with BMS implantation followed by kissing DEB. The same type of BMS was correspondingly implanted in silicone bifurcation models and scanned by microcomputed tomography., Results: Overall, a total 2914 struts were analyzed, revealing 0.6% malapposed struts and 3.1% uncovered struts, with neointimal thickness of covered struts measured at 0.19 ± 0.13 mm. Findings were homogeneous among patients with the exception of one outlier who presented a significant distortion of the stent geometry, suggesting proximal cell rewiring prior to kissing DEB, as supported by the microcomputed tomography model. This pattern was not present in the other cases, which showed struts optimally apposed and nicely scaffolding the side-branch ostium., Conclusion: This is the first study describing the effects of DEB in percutaneous bifurcation interventions according to OCT parameters. The results show that a strategy of kissing DEB following BMS is associated with low neointimal thickness and high rate of covered stent struts. Moreover, these results appear to be dependent on the quality of bifurcation intervention, with distal cell rewiring more favorable than proximal cell rewiring.

Advances in the understanding of healing mechanisms after stent implantation have led to the recognition of stent strut thickness as an essential factor affecting re-endothelialization and overall long term vessel healing response after Percutaneous Coronary Interventions (PCI). Emergence of Drug-eluting stents (DESs) with anti-proliferative coating has contributed to reducing the incidence of restenosis and Target Lesion Revascularization (TVR), while progress and innovations in stent materials have in the meantime facilitated the design of newer platforms with more conformability and thinner struts, producing lesser injury and improving integration into the vessel wall. Recent advances in biodegradable metal and polymer materials now also allow for the design of fully biodegradable platforms, which are aimed at scaffolding the vessel only temporarily to prevent recoil and constrictive remodeling of the vessel during the initial period required, and are then progressively resorbed thereby avoiding the drawback of leaving an unnecessary implant permanently in the vessel. The aim of this article is to review recent evolution in stent material and stent strut design while understanding their impact on PCI outcomes. The article describes the different metallic alloys and biodegradable material properties and how these have impacted the evolution of stent strut thickness and ultimately outcomes in patients., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Objectives: The aim of this study was to perform hemodynamic mapping of the entire vessel using motorized pullback of a pressure guidewire with continuous instantaneous wave-free ratio (iFR) measurement., Background: Serial stenoses or diffuse vessel narrowing hamper pressure wire-guided management of coronary stenoses. Characterization of functional relevance of individual stenoses or narrowed segments constitutes an unmet need in ischemia-driven percutaneous revascularization., Methods: The study was performed in 32 coronary arteries with tandem and/or diffusely diseased vessels. An automated iFR physiological map, integrating pullback speed and physiological information, was built using dedicated software to calculate physiological stenosis severity, length, and intensity (ΔiFR/mm). This map was used to predict the best-case post-percutaneous coronary intervention (PCI) iFR (iFRexp) according to the stented location, and this was compared with the observed iFR post-PCI (iFRobs)., Results: After successful PCI, the mean difference between iFRexp and iFRobs was small (mean difference: 0.016 ± 0.004) with a strong relationship between ΔiFRexp and ΔiFRobs (r = 0.97, p < 0.001). By identifying differing iFR intensities, it was possible to identify functional stenosis length and quantify the contribution of each individual stenosis or narrowed segment to overall vessel stenotic burden. Physiological lesion length was shorter than anatomic length (12.6 ± 1.5 vs. 23.3 ± 1.3, p < 0.001), and targeting regions with the highest iFR intensity predicted significant improvement post-PCI (r = 0.86, p < 0.001)., Conclusions: iFR measurements during continuous resting pressure wire pullback provide a physiological map of the entire coronary vessel. Before a PCI, the iFR pullback can predict the hemodynamic consequences of stenting specific stenoses and thereby may facilitate the intervention and stenting strategy., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to compare the acute performance of the PLLA ABSORB bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) with second-generation metal drug-eluting stents (DES) in complex coronary artery lesions., Background: Thick polymer-based BVS have different mechanical properties than thin second-generation DES. Data on the acute performance of BVS are limited to simple coronary lesions treated in trials with strict inclusion criteria., Methods: Fifty complex coronary lesions (all type American College of Cardiology/American Heart Association B2-C) treated with a BVS undergoing a final optical coherence tomography (OCT) examination were compared with an equal number of matched lesions treated with second-generation DES. The following stent performance indexes were assessed with OCT: mean and minimal area, residual area stenosis (RAS), incomplete strut apposition (ISA), tissue prolapse, eccentricity index, symmetry index, strut fracture, and edge dissection., Results: One hundred lesions from 73 patients were analyzed. A higher balloon diameter/reference vessel diameter ratio was used for predilation in the BVS group (p < 0.01). Most of the BVS and DES were post-dilated with short noncompliant (NC) balloons of similar diameter. OCT showed in the BVS group a higher tissue prolapse area (p = 0.08) and greater incidence of ISA at the proximal edge (p = 0.04) with no difference in the overall ISA. The RAS was 20.2% in the BVS group and 21.7% in the DES group (p = 0.32). There was no difference in the eccentricity index. The minimal and mean lumen areas were similar in the 2 groups. Two cases of strut fractures occurred after the BVS, whereas none was observed in the DES., Conclusions: Based on OCT, the BVS showed similar post-procedure area stenosis, minimal lumen area, and eccentricity index as second-generation DES. The different approach for lesion preparation and routine use of OCT guidance during BVS expansion may have contributed to these results., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: Stent fracture (SF) is an uncommon complication following percutaneous coronary intervention. Previous studies of SF have either been small single-center studies or have reported data mainly from first generation platforms. The FDA MAUDE database was used to identify cases of SF to gain mechanistic insight into procedural and anatomical factors predisposing to this complication, to define treatment and associated clinical outcomes in contemporary and first generation stent platforms., Methods and Results: Using defined search terms, 376 unique reports of SF were identified in the FDA MAUDE database of which 336 (89.4%) occurred in first generation stent platforms with 96.1% occurring in the Cypher platform. The remaining 40 reports (10.6%) occurred with a similar distribution of cases across different contemporary platforms. Common vessel characteristics associated with SF included calcification, tortuosity, stent overlap, and significant angulation with the most common modality of presentation being in-stent restenosis or stent thrombosis., Conclusions: SF occurs most commonly in first generation Cypher stents with a similar distribution of cases across different contemporary platforms. Optimal treatment strategy remains unclear with the decision to treat and the modality of treatment utilized depending on the type and severity of SF., (Copyright © 2014 Wiley Periodicals, Inc.)

Aims: Characterization of neointimal tissue is essential to understand the pathophysiology of in-stent restenosis (ISR) after drug eluting stent (DES) implantation. Using optical coherence tomography (OCT), we compared the morphologic characteristics of ISR between first and second generation DES., Methods and Results: OCT was performed in 66 DES-ISR, defined as > 50% angiographic diameter stenosis within the stented segment. Patients with ISR of first generation sirolimus-eluting stents (SES), paclitaxel eluting stents (PES) and second generation zotarolimus-eluting stents (ZES), everolimus-eluting stents (EES) and biolimus-eluting stents (BES) were enrolled. Quantitative and qualitative ISR tissue analysis was performed at 1-mm intervals along the entire stent, and categorised as homogeneous, heterogeneous and neo-atherosclerosis. The presence of microvessels and peri-strut low intensity area (PSLIA) was determined in all ISR. Neoatherosclerosis was identified by lipid, calcium and thin-cap fibro-atheroma (TCFA) like lesions. We compared the two DES generations at both early (< 1 year) and late (> 1 year) follow-ups.In second generation DES a heterogeneous pattern was prevalent both before and after 1 year (57.1% and 58.6% respectively). Neo-atherosclerosis was more common in the early period in first generation DES (19.4% vs 11.7%, p < 0.01), but after one year was more prevalent in second generation DES (7.0% vs 19.3%, p < 0.01). Similar prevalence of TCFAs was observed in both groups in all comparisons., Conclusions: When ISR restenosis occurs in second generation DES, the current data suggest a different time course and different morphological characteristics from first generation. Future prospective studies should evaluate the relationship between ISR morphology, time course and clinical events.

Objectives: This study sought to better understand and optimize provisional main vessel stenting with final kissing balloon dilation (FKBD)., Background: Main vessel stenting with FKBD is widely used, but many technical variations are possible that may affect the final result. Furthermore, most contemporary stent designs have a large cell size, making the impact of stent platform selection for this procedure unclear., Methods: Finite element simulations were used to virtually deploy and post-dilate 3 stent platforms in 3 bifurcation models. Two FKBD strategies were evaluated: simultaneous FKBD (n = 27) and modified FKBD (n = 27). In the simultaneous FKDB technique, both balloons were simultaneously inflated and deflated. In the modified FKBD technique, the side branch balloon was inflated first, then partially deflated, followed by main branch balloon inflation., Results: Modified FKBD results in less ostial stenosis compared with simultaneous FKBD (15 ± 9% vs. 20 ± 11%; p < 0.001) and also reduces elliptical stent deformation (ellipticity index, 1.17 ± 0.05 vs. 1.36 ± 0.06; p < 0.001). The number of malapposed stent struts was not influenced by the FKBD technique (modified FKBD, 6.3 ± 3.6%; simultaneous FKBD, 6.4 ± 3.4%; p = 0.212). Stent design had no significant impact on the remaining ostial stenosis (Integrity [Medtronic, Inc., Minneapolis, Minnesota], 16 ± 11%; Omega [Boston Scientific, Natick, Massachusetts], 17 ± 11%; Multi-Link 8 [Abbott Vascular, Santa Clara, California], 19 ± 8%)., Conclusions: The modified FKBD procedure reduces elliptical stent deformation and optimizes side branch access., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Malapposition of stent struts to the arterial wall and suboptimal stent expansion have been linked with poor outcomes following percutaneous coronary intervention (PCI). The purpose of this study was to use optical coherence tomography (OCT) to investigate stent strut malapposition in relation to calcium distribution., Methods and Results: Twenty-three PCI patients underwent OCT before and after stent deployment. Patient and procedural details and lesion characteristics - including the extent and depth of calcification - were measured, and the number of malapposed struts following final postdilatation was quantified. Patient and lesion characteristics associated with malapposition were assessed using univariate and multivariate analyses. The mean lesion length was 25.2 ± 10.8 mm, with a minimal lumen area (MLA) of 2.2 ± 1.2 mm². Eight percent of all stent struts were malapposed, most commonly in the proximal part of the stent. By univariate analysis, the percentage of malapposed struts was found to correlate with the circumferential extent of calcification (P=.04); however, no correlation was seen with the depth of calcification. Using multivariate analysis, the circumferential extent of vessel wall calcification was the only plaque feature found to correlate with the percentage of malapposed struts (P=.01)., Conclusions: Using OCT to assess vessel wall characteristics, the circumferential extent of superficial calcification seen, and not the depth, correlated well with the percentage of malapposed struts following PCI.

Current in vivo models of arterial lesions often lead to unpredictable results in terms of lesion anatomy and hemodynamical significance. This study aimed to evaluate the impact of coronary stenosis using a novel in vivo adjustable stenosis model capable of mimicking advanced human coronary lesions. We developed a series of balloon expandable covered coronary stents with a central restriction, mimicking different intermediate to severe stenosis, and implanted them percutaneously in coronary arteries of eight healthy hybrid Landrace pigs. Optical coherence tomography (OCT) pullbacks and fractional flow reserve (FFR) were acquired along the artery after implantation of the stenotic stents for precise evaluation of anatomy and functional impact. Diameter and area stenosis after deployment of the stenosis implant were, on average, respectively, 54.1 ± 5.9 and 78.4 ± 5.8 % and average FFR value was 0.83 (SD 0.13). There was a low correlation between FFR and MLA evaluated by OCT (r = 0.02, p = 0.94), improved with percentage area stenosis (r = -0.55, p = 0.12), or OCT volumetric evaluation of the stenosis taking into account not only the MLA but also the length of the lesion (r = -0.78, p = 0.01). This study presents a method and proof of concept for percutaneously introducing, and removing, anatomical stenosis of predetermined severity in vivo. Such in vivo model may be used to create and evaluate the impact of focal stenoses on physiological parameters such as FFR.

Purpose: To allow an accurate diagnosis of coronary artery diseases by enhancing optical coherence tomography (OCT) images of atheromatous plaques using a novel automated attenuation compensation technique., Background: One of the major drawbacks of coronary OCT imaging is the rapid attenuation of the OCT signal, limiting penetration in tissue to only few millimetres. Visualisation of deeper anatomy is however critical for accurate assessment of plaque burden in-vivo., Methods: A compensation algorithm, previously developed to correct for light attenuation in soft tissues and to enhance contrast in ophthalmic OCT images, was applied to intracoronary plaque imaging using spectral-domain OCT., Results: Application of the compensation algorithm significantly increased tissue contrast in the vessel wall and atherosclerotic plaque boundaries. Contrast enhancement allows a better differentiation of plaque morphology, which is particularly important for the identification of lipid rich fibro atheromatous plaques and to guide decision on treatment strategy., Conclusion: The analysis of arterial vessel structure clinically captured with OCT is improved when used in conjunction with automated attenuation compensation. This approach may improve the OCT-based interpretation of coronary plaque morphology in clinical practice., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: A tubular stent may adapt with difficulty to coronary bifurcation lesions (CBLs)., Methods: Time domain or frequency domain (FD) optical coherence tomography (OCT) was performed to assess strut apposition immediately after stent implantation across four segments inside the bifurcation, in a consecutive series of patients. OCT pullbacks were performed in the main vessel (MV)., Results: A total of 13,142 struts in 45 CBL in 41 patients were assessed. Strut malapposition was significantly more frequent in the half bifurcation facing the side-branch (SB) ostium (42.9%) than in the proximal segment of the bifurcation 11.8%, half bifurcation opposite the SB 6.7%, or the distal segment 5.7% (all P < 0.0001). Lesions (n = 15) treated with stenting of both MV and SB had a total higher rate of malapposition than those (n = 30) treated with stenting of the MV only (17.6% vs. 9.5%; P = 0.0014). In latter group, lesions treated with FD-OCT-guided stent implantation (n = 13) presented a lower rate of malapposition than those treated with conventional angiographic-guided stent implantation (n = 17) (7.1% vs. 17.5%; P = 0.005)., Conclusions: In CBL, strut malapposition is particularly high at the SB ostium. However, a strategy of stenting MV only with adjunctive FD-OCT guidance is associated with lower rates of malapposition., (Copyright © 2012 Wiley Periodicals, Inc.)

Aims: The aim of this study was to assess the ability of optical coherence tomography (OCT) to guide recrossing during percutaneous coronary interventions in bifurcations and to reduce strut malapposition., Methods and Results: Fifty-two patients undergoing elective treatment of bifurcation lesions using provisional stenting as default strategy were included in the study. Patients were divided into two groups: OCT-guided stent recrossing (group 1, n=12), and angiography-guided recrossing (group 2, n=40). Malapposition in the various bifurcation segments was compared in the two groups, using propensity score analysis to correct for confounders. In 4/12 patients (33%) of the OCT-guided group after the first attempt to recross the stent towards the SB the wire was found to have crossed in a proximal cell, requiring a second and in one case a third attempt to successfully cross through a distal cell. Patients who were treated using OCT-guided recrossing had a significantly lower number of malapposed stent struts, especially in the quadrants towards the SB ostium (9.5%[7.5-17.4%] vs 42.3%[31.2-54.7%] in the angiography-guided group, p<0.0001)., Conclusions: The rate of strut malapposition was significantly reduced when OCT was used to confirm that wire recrossing was performed in a distal cell of the SB ostium.

Optical coherence tomography (OCT) is a high-resolution imaging technique with great versatility of applications. In cardiology, OCT has remained hitherto as a research tool for characterization of vulnerable plaques and evaluation of neointimal healing after stenting. However, OCT is now successfully applied in different clinical scenarios, and the introduction of frequency domain analysis simplified its application to the point it can be considered a potential alternative to intravascular ultrasound for clinical decision-making in some cases. This article reviews the use of OCT for assessment of lesion severity, characterization of acute coronary syndromes, guidance of intracoronary stenting, and evaluation of long-term results.

Objectives: This study sought to evaluate post-dilation strategies in bifurcation stenting., Background: In bifurcation stenting practice, it is still controversial how post-dilation should be performed and whether the kissing balloon (KB) technique is mandatory when only the main vessel (MV) receives a stent., Methods: A series of drug-eluting stents (DES) (n = 26) were deployed in a coronary bifurcation model following a provisional approach. After the deployment of the stent in the MV, post-dilation with the KB technique was compared with a 2-step, sequential post-dilation of the side branch (SB) and MV without kissing., Results: The percentage of the SB lumen area free of stent struts was similar after KB (79.1 ± 8.7%) and after the 2-step sequence (74.4 ± 11.6%, p = 0.25), a considerable improvement compared with MV stenting only without dilation of the stent at the SB ostium (30.8 ± 7.8%, p < 0.0001). The rate of strut malapposition in the ostium was 21.3 ± 9.2% after KB and 24.9 ± 10.4% after the 2-step sequence, respectively, a significant reduction compared with a simple SB dilation (55.3 ± 16.8%, p < 0.0001) or MV stenting only (47.0 ± 8.5%, p < 0.0005). KB created a significant elliptical overexpansion of the MV lumen, inducing higher stress concentration proximal to the SB. KB also led to a higher risk of incomplete stent apposition at the proximal stent edge (30.7 ± 26.4% vs. 2.8 ± 9.6% for 2-step, p = 0.0016)., Conclusions: Sequential 2-step post-dilation of the SB and MV may offer a simpler and more efficient alternative to final KB technique for provisional stenting of bifurcations., (Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: High rates of restenosis and stent thrombosis are still often observed after bifurcation stenting despite the recommended stent post-dilatation using the kissing balloon (KB) technique. We investigated the potential benefits of a final post-dilatation step in bifurcation stenting with a balloon that respects the natural diameter ratio of the proximal and distal vessels in bifurcations (Murray's law)., Methods and Results: Fourteen commercially available stents (Xience V, Taxus Liberté and Presillion) were deployed in a silicone model of a coronary bifurcation using a provisional stenting approach. After side branch (SB) ostium dilatation and KB inflation, stent geometry and strut apposition was analysed using micro-CT. A final proximal inflation step was then performed to post-dilate only the proximal segment of the main vessel (MV). KB inflation produces an asymmetrical dilatation of the stent in the proximal part of the bifurcation with a number of struts left malapposed in the MV. Using the proposed final proximal inflation (FPI) step reduces the average stent eccentricity index from 0.72 to 0.90 (p<0.001) and the percentage of malapposed struts in the proximal part of the MV from 33.4% to 0.6% (p=0.02), while increasing the minimum stent area from 6.8 mm² to 8.5 mm² (p < 0.0001)., Conclusions: A final dilatation of the stent only in the MV proximal to the SB with a balloon sized according to the mother vessel is suggested to prevent stent malapposition and optimise stent deployment in bifurcation stenting.

We report the case of a 64-year-old man treated for stable angina with two bare-metal stents in the proximal-mid segment of the left anterior descending artery at the bifurcation with the first diagonal and second septal branches without final kissing balloon dilatation. Seven months later he complained of recurrent angina. Frequency-domain optical coherence tomography (OCT) with three-dimensional (3D) reconstruction was performed, showing a thick rim of neointimal proliferation at the ostium of both branches, causing severe restenosis. Deployment of a stent in a bifurcation main branch without opening the struts at the side-branch ostium may facilitate focal restenosis.