The Proximal Optimisation Technique for Intervention of Coronary Bifurcations.

Main vessel (MV) stent deformation and overstretch caused by classical kissing balloon inflation (C-KBI) using two balloons with a longer overlapping in the MV for bifurcation lesions has caused a widespread concern. This bench study tested our hypothesis that mini-KBI (M-KBI) with a shorter protrusion of side branch (SB) balloon would ascertain a better result after Culotte stenting. Twenty-four coronary stents were deployed using Culotte approach in twelve bifurcation models with a bifurcation angle of 45°, 3.5 mm in MV diameter, and 3.0 mm in SB diameter. After stent implantation, the final KBI were assigned to C-KBI (two kissing balloons juxtaposed within the MV stent, at least overlap for 3 mm; n = 6) and M-KBI (the proximal marker of SB balloon just sited at the level of upper edge of SB ostium; n = 6). Proximal optimization technique (POT) was performed after KBI. Stent geometry was visually evaluated based on bench photos, microscopy, videoscopy, micro-CT, and scanning electron microscopy. Stent deformation index, minimal lumen diameter, and cross-sectional area at either carina level of MV and ostium of SB were measured from optical coherence tomography (OCT). In Culotte technique, C-KBI was associated with visually significant stent deformation, overexpansion and the "bottleneck" effect of the MV stent, which could not be effectively rectified by POT, while M-KBI could keep the circle shape of MV stent with good stent apposition in both MV and SB stent. By quantitative measurements, deformation index of MV was 0.06 ± 0.01 after M-KBI, significantly lower than 0.25 ± 0.02 if C-KBI was performed. In the line in carina, compared to C-KBI, M-KBI has smaller CSA-stent/CSA-reference, which indicated a less overstretch of MV stent. However, minimal lumen diameter and cross-sectional area of SB ostium was not different in the mini-KBI group (3.0958 ± 0.0285 mm and 7.9667 ± 0.1741 mm), when compared those after C-KBI (3.1217 ± 0.0772 mm and 7.9083 ± 0.3115 mm, p > .05). Followed by POT, M-KBI is preferable than C-KBI in preventing stent deformation, overexpansion in MV stent and could get well apposed of MV stent and well-opened SB stent as expected in a Culotte technique.

Predictors and Outcomes of Side Branch Occlusion After Main Vessel Stenting in Coronary Bifurcation Lesions: Results From the COBIS II Registry (COronary BIfurcation Stenting)

Optimal balloon positioning to maximize the proximal optimization technique (POT)

Objective To investigate and compare the pattern of instent neointimal formation and native atherosclerosis in the coronary bifurcation lesions by volumetric analysis using systematic intravascular ultrasound (IVUS). Methods This study examined 102 native coronary artery bifurcation lesions and 51 post-stenting bifurcation lesions treated with drug-eluting stents using the T-stenting technique at 9-month follow-up IVUS images for both main vessel and side branch. Three interested segments were analysed: proximal main vessel (MVp) ostium, distal main vessel (MVd) and side branch ostium (SBo). At each segment, four quadrant analysis was performed per 1 mm by measuring the vessel area (stent area in the post-stenting lesions), lumen area and calculating the plaque area for volumetric analysis. Results In the plaque group, the plaque volume differed significantly between the four quadrants (P When the left main (LM) bifurcation (n = 38) was analysed separately, the abcarinal quadrant still had the largest plaque volume and the carinal quadrant the least in all three segments, while the epicardial and myocardial quadrant did not differ in the MVp (P = 0.99). In the MVd and SBo, the plaque volume of myocardial quadrant was still significantly greater than the epicardial quadrant (P In the neointima group, the neointimal volume differed significantly in the MVp and MVd (P = 0.002, P = 0.002, separately), while the four quadrants did not differ in the SB (P = 0.281). In the MVp and MVd, the neointimal volume was larger in the abcarinal than the carinal quadrant (in MVp, 4.8 mm3 [IQR 2.7.6.3 mm3] vs.2.1 mm3 [IQR 0.5.3.9 mm3], P When comparing the eccentricity indices between plaque and neointima groups, there was no difference in the MVp, while the neointima group was significantly smaller than plaque group in the MVd (1.6 [IQR 0.8, 2.8] vs. 4.7 [IQR 2.1, 8.7], P Conclusions The distribution of neointimal proliferation and seems to have a similar pattern to that of atherosclerotic plaque in native coronary arteries, particularly in the main vessel, but the trend is less prominent.

We compared the mechanisms of lumen gain after Cappella Sideguard (CS) side branch (SB) bifurcation stent deployment versus a balloon-expandable stent in the corresponding main vessel (MV). The novel CS SB bifurcation stent is a self-expanding, thin-strut, nitinol device with anatomic flaring at the SB ostium. In 28 bifurcation lesions, intravascular ultrasound imaging of both the SB and the MV was performed both pre- and postintervention; vessel and lumen areas were measured every 1 mm over a 5 mm segment beginning at the carina. Although minimum lumen area (MLA) within the distal 5 mm segment beginning at the carina increased from 2.8 ± 1.3 mm(2) to 3.8 ± 1.1 mm(2), P < 0.001, in the SB and from 3.4 ± 1.4 mm(2) to 6.0 ± 1.1 mm(2), P < 0.001, in the MV, stent expansion (minimum stent area/distal reference lumen area) was significantly less in the SB compared with the MV (77.8 ± 21.3% vs. 91.6 ± 18.4%, P = 0.02). Post stenting, the MLA site was located at the carina more frequently in the SB (85.7%) than in the MV (60.7%), P = 0.04. Plaque volume in the 5 mm proximal to carina in the MV tended to decrease, whereas plaque volume in the SB increased slightly with no change in overall plaque volume in the 5-mm-long segment distal to the carina in the MV, suggesting plaque shift from the proximal MV to the SB. Acute CS lumen gain is less than the lumen gain of a balloon-expandable stent in the MV because of less aggressive acute expansion and/or the plaque shift from the proximal MV to the SB.

Coronary bifurcations are involved in 15-20% of all percutaneous coronary interventions (PCI) and remain one of the most challenging lesions in interventional cardiology in terms of procedural success rate as well as long-term cardiac events. The optimal management of bifurcation lesions is, despite a fast growing body of scientific literature, the subject of considerable debate. The European Bifurcation Club (EBC) was initiated in 2004 to support a continuous overview of the field, and aims to facilitate a scientific discussion and an exchange of ideas on the management of bifurcation disease. The EBC hosts an annual, compact meeting, dedicated to bifurcations, which brings together physicians, engineers, biologists, physicists, epidemiologists and statisticians for detailed discussions. Every meeting is finalised with a consensus statement which reflects the unique opportunity of combining the opinions of interventional cardiologists with the opinions of a large variety of other scientists on bifurcation management. The present 11th EBC consensus document represents the summary of the up-to-date EBC consensus and recommendations. It points to the fact that there is a multitude of strategies and approaches to bifurcation stenting within the provisional strategy and in the different two-stent strategies. The main EBC recommendation for PCI of bifurcation lesions remains to use main vessel (MV) stenting with a proximal optimisation technique (POT) and provisional side branch (SB) stenting as a preferred approach. The consensus document covers a moving target. Much more scientific work is needed in non-left main (LM) and LM bifurcation lesions for continuous improvement of the outcome of our patients.

Provisional stenting is considered the gold standard approach for most bifurcation lesions, but the benefit of routine side branch (SB) strut dilatation has not been fully elucidated. A benchtop model was used to determine the benefits of routine side branch (SB) dilatation techniques on strut apposition, acute thrombogenicity, and flow disruption. Three different provisional bifurcation techniques were compared: no SB dilatation "keep it open" method (KIO), sequential balloon dilatation (SBD), and kissing balloon inflation (KBI). Stents were deployed in a silicon bifurcation model and perfused with blood at a flow rate of 200 ml/min for 60 min. Optical coherence tomography (OCT) pullbacks were obtained before and after flow perfusion to conduct strut analysis and acute thrombus measurement respectively. Computational fluid dynamics (CFD) models were created using OCT pullbacks and simulated based on experimental conditions to analyze flow disruption. The strut analysis showed that KBI had the lowest percentage of floating (10.6 ± 2.3%) (p = 0.0004) and malapposed (41.2 ± 8.5%) struts (p = 0.59), followed by SBD and then KIO. This correlated to KBI having the lowest amount of thrombus formed at the SB, followed by SBD, with KIO being the most thrombogenic (KBI: 0.84 ± 0.22mm2, SBD: 1.17 ± 0.25mm2, KIO: 1.31 ± 0.36mm2, p = 0.18). CFD models also predicted a similar trend, with KBI having the lowest amount of area of high shear rate as well as flow recirculation. Based on this benchtop model, SB intervention strategies demonstrated a reduction in number of struts and resulting thrombogenicity at the bifurcation ostia. Graphical abstract.

To determine the frequency of side branch (SB) occlusion during percutaneous coronary intervention (PCI) with stenting of bifurcation lesions and to assess the predictors of side branch occlusion in local population. Cross-sectional study. Cardiac Catheterization Lab, Rawalpindi Institute of Cardiology, Rawalpindi, from July 2016 to January 2017. A total of 200 patients fulfilling the inclusion criteria were included in the study with non-probability consecutive sampling technique. Variables like diameters and lesion lengths of main vessel and side branch were recorded using quantitative coronary analysis software (QCA). The SB occlusion was defined as <3 TIMI score following main vessel PCI with stenting. The data was analysed using SPSS version 21.0. Mean age (years) of the study population was 52.27 ±13.33 including 180 (90.0%) male and 20 (10.0%) female patients. SB occlusion was observed in 15 (7.5%) of cases. Mean SB diameter was significantly larger in cases without SB occlusion than those with SB occlusion (2.06 ±0.09 vs. 2.17 ±0.26, p=0.003). Similarly, SB lesions were significantly shorter in length in those without SB occlusion than those with SB occlusion (3.53 ±0.51 and 4.66 ±3.11, p<0.001). However, mean MV diameter (mm) and mean MV lesions length (mm) in both the groups were statistically not significant. Mean SB diameter and lesion length are useful predictors of SB occlusion during stenting of bifurcation lesions in the local population.

Introduction. Stenting of bifurcation lesions of the coronary arteries is a pressing issue in interventional cardiology that requires constant adaptation to modern technical advances and patient needs. Optimized treatment methods should take into account morphological features, the potential for plaque formation in the main vessel and in the side branch; ensure long-term efficacy and a low risk of restenosis in the distant period. Objective. To evaluate the immediate results of surgical treatment of bifurcation lesions of the coronary arteries using a modified provisional stenting technique. Materials and methods. In three groups of patients with bifurcation lesions of the coronary arteries, provisional stenting was performed using classical generally accepted techniques (side branch dilation with proximal optimization in the first group and kissing dilation with proximal optimization in the second) and a modified technique i. e. local post-dilation of the stent cell with proximal optimization was used in the third group. After the surgery, we performed OCT control, analyzed in-hospital complications and the following parameters: stenosis of the main and side branches (OCT MB and SB, %); diameter of the main branch (mm); malposition of stent struts (%). Results. When comparing the frequency of major adverse cardiovascular events (MACE), angiographic success in MB and SB, MB predilation, transition to a two-stent technique, as well as the number of stents and guidewires used during the intervention, no statistically significant differences were found in the compared groups. However, when using the modified technique, there was a tendency to reduce the time of X-ray radiation (p=0.37) and the number of balloon catheters used (p=0.55), as well as a decrease in the percentage of malpositioned struts (p=0.31) according to the results of OCT control in comparison with classical techniques. Conclusion. The proposed modified technique of provisional stenting of bifurcation lesions of the coronary arteries is comparable in efficiency and applicability with classical, generally accepted methods of provisional stenting, and also demonstrates ease of implementation and safety in the medium term. The technique demonstrates better geometry of the stented section of neobifurcation; it allows to reduce the risk of thrombosis in the early postoperative period due to complete and optimal adhesion of the stent to the artery.

The rePOT (proximal optimisation technique) sequence proved significantly more effective than final kissing balloon (FKB) with two drug-eluting stents (DES) in a bench test. We sought to validate efficacy experimentally in a large range of latest-generation DES. On left main fractal coronary bifurcation bench models, five samples of each of the six main latest-generation DES (Coroflex ISAR, Orsiro, Promus PREMIER, Resolute Integrity, Ultimaster, XIENCE Xpedition) were implanted on rePOT (initial POT, side branch inflation, final POT). Proximal elliptical ratio, side branch obstruction (SBO), stent overstretch and strut malapposition were quantified on 2D and 3D OCT. Results were compared to FKB with Promus PREMIER. Whatever the design, rePOT maintained vessel circularity compared to FKB: elliptical ratio, 1.02±0.01 to 1.04±0.01 vs. 1.26±0.02 (p<0.05). Global strut malapposition was much lower: 2.6±1.4% to 0.1±0.2% vs. 40.4±8.4% for FKB (p<0.05). However, only Promus PREMIER and XIENCE Xpedition achieved significantly less SBO: respectively, 5.6±3.5% and 10.0±5.3% vs. 23.5±5.7% for FKB (p<0.05). Platform design differences had little influence on the excellent results of rePOT versus FKB. RePOT optimised strut apposition without proximal elliptical deformation in the six main latest-generation DES. Thickness and design characteristics seemed relevant for optimising SBO.

Abnormal blood flow patterns promoting inflammation, cellular proliferation, and thrombosis may be established by local changes in vessel geometry after stent implantation in bifurcation lesions. Our objective was to quantify altered hemodynamics due to main vessel (MV) stenting and subsequent virtual side branch (SB) angioplasty in a coronary bifurcation by using computational fluid dynamics (CFD) analysis. CFD models were generated from representative vascular dimensions and intravascular ultrasound images. Time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and fractional flow reserve (FFR) were quantified. None of the luminal surface was exposed to low TAWSS (<4 dyn/cm(2)) in the nondiseased bifurcation model. MV stenting introduced eccentric areas of low TAWSS along the lateral wall of the MV. Virtual SB angioplasty resulted in a more concentric region of low TAWSS in the MV distal to the carina and along the lateral wall of the SB. The luminal surface exposed to low TAWSS was similar before and after virtual SB angioplasty (rest: 43% vs. 41%; hyperemia: 18% vs. 21%) and primarily due to stent-induced flow alterations. Sites of elevated OSI (>0.1) were minimal but more impacted by general vessel geometry established after MV stenting. FFR measured at a jailed SB was within the normal range despite angiographic stenosis of 54%. These findings indicate that the most commonly used percutaneous interventional strategy for a bifurcation lesion causes abnormal local hemodynamic conditions. These results may partially explain the high clinical event rates in bifurcation lesions.

Ultrasound Findings During Percutaneous Treatment of Bifurcated Coronary Lesions

Serial Intravascular Ultrasound Analysis of the Main and Side Branches in Bifurcation Lesions Treated With the T-Stenting Technique

To characterize the treatment of complex bifurcation lesions (BL) with the Tryton Bifurcation Stent (TBS) paired with an everolimus-eluting stent (EES). Complex BL are associated with higher procedural complications and poorer long-term outcomes. The TBS is a dedicated side-branch (SB) stent designed to be used in conjunction with a standard drug-eluting stent. Prospectively identified, consecutive patients underwent TBS+EES stenting of BL using a protocol which included TBS postdilation and simultaneous final kissing balloon inflations (FKBI). All lesions were systematically evaluated with coronary angiography and IVUS, obtained at procedure completion and at 9 months, and were assessed by independent core laboratories. Thirty-three BL were treated in 32 patients presenting primarily (87.5%) with stable angina and complex BL with angiographic apparent disease in the main vessel (MV) and SB in 87.9% and 75% by site and core evaluation, respectively. Procedural success was 100% and high postprocedure percent stent expansion (MV 96 [93, 109]%, SB 88 [77, 100]%, carina MV 135 [99, 166]%, carina SB 116 [91, 130]%) was demonstrated by IVUS. At 9-month angiographic follow-up (n = 28 patients), one MV in-segment restenosis and one SB in-stent restenosis were observed. SB in-stent late lumen loss was 0.41 ± 0.27 mm. IVUS assessment revealed the absence of stent recoil; percent carinal neointimal hyperplasia (NIH) was 1.8 [0.0,11.2]% in MV and 15.0 [6.7,23.5]% in SB, with NIH volume obstruction of 2.0 [0.7,4.3]% in MV and 14.2 [7.5,29.6]% in SB. Stenting of complex BL with the TBS+EES provides high acute success with sustained clinical, angiographic, and IVUS results at 9 months. These excellent results are likely due to the extent of stent expansion at the carina.

A tubular stent may adapt with difficulty to coronary bifurcation lesions (CBLs). 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). 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). 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.