Success rate and influencing factors of a balloon-push technique: A new technique to remove side branch-jailed struts under three-dimensional optical coherence tomography guidance.

BACKGROUND: Kissing balloon inflation with distal guide wire recross can cause severe stent deformation depending on the stent link location with respect to the carina. The balloon-push technique, by which an inflated balloon is forced into the SB from the proximal main vessel (MV), is a feasible way to remove jailed struts without causing severe stent deformation. AIMS: We investigated the procedural success rate, patterns of jailed strut removal at side branch (SB) orifices, factors related to failure of jailed strut removal, and follow-up angiogram results of the balloon-push technique. METHODS: Between September 2015 and December 2020, 51 bifurcation stenting cases in which the balloon-push technique was used were enrolled. Based on three-dimensional optical coherence tomography images, strut removal with 1 stent crown length was defined as successful. Strut removal patterns were classified into two types: parallel-slide type (stent struts shifted distally into the MV lumen without inversion) and under-carina type (stent struts shifted distally under the carina with strut inversion or strut slide). RESULTS: Procedural success was attained in 39 cases (success rate: 76.5%). Parallel-slide type and under-carina type occurred in 43% and 33% of cases, respectively. Factors related to failure were trifurcation lesions and a smaller pushed balloon-SB artery ratio compared with those in success cases (0.95 ± 0.18 vs. 1.10 ± 0.22, p = 0.032). Follow-up angiography was performed in 37 cases, and 2 cases had binary in-stent restenosis. CONCLUSIONS: Removal of jailed struts with the balloon-push technique was feasible, without severe stent deformation, in bifurcation stentings.

Risk Assessment of Side Branch Compromise After Coronary Bifurcation Stenting　- A Substudy of the 3D-OCT Bifurcation Registry.

BACKGROUND: Side branch (SB) occlusion during bifurcation stenting is a serious complication. This study aimed to predict SB compromise (SBC) using optical coherence tomography (OCT).Methods and Results: Among the 168 patients who enrolled in the 3D-OCT Bifurcation Registry, 111 bifurcation lesions were analyzed to develop an OCT risk score for predicting SBC. SBC was defined as worsening of angiographic SB ostial stenosis (≥90%) immediately after stenting. On the basis of OCT before stenting, geometric parameters (SB diameter [SBd], length from proximal branching point to carina tip [BP-CT length], and distance of the polygon of confluence [dPOC]) and 3-dimensional bifurcation types (parallel or perpendicular) were evaluated. SBC occurred in 36 (32%) lesions. The parallel-type bifurcation was significantly more frequent in lesions with SBC. The receiver operating characteristic curve indicated SBd ≤1.77 mm (area under the curve [AUC]=0.73, sensitivity 64%, specificity 75%), BP-CT length ≤1.8 mm (AUC=0.83, sensitivity 86%, specificity 68%), and dPOC ≤3.96 mm (AUC=0.68, sensitivity 63%, specificity 69%) as the best cut-off values for predicting SBC. To create the OCT risk score, we assigned 1 point to each of these factors. As the score increased, the frequency of SBC increased significantly (Score 0, 0%; Score 1, 8.7%; Score 2, 28%; Score 3, 58%; Score 4, 85%; P<0.0001). CONCLUSIONS: Prediction of SBC using OCT is feasible with high probability.

Peri-Balloon Leak Flow Velocity Assessed by Intra-Cardiac Echography Predicts Pulmonary Vein Electrical Gap　- Intra-Cardiac Echography-Guided Contrast-Free Cryoballoon Ablation.

BACKGROUND: The use of iodine contrast agents is one possible limitation in cryoballoon ablation (CBA) for atrial fibrillation (AF). This study investigated intracardiac echography (ICE)-guided contrast-free CBA.Methods and Results:The study was divided into 2 phases. First, 25 paroxysmal AF patients (Group 1) underwent CBA, and peri-balloon leak flow velocity (PLFV) was assessed using ICE and electrical pulmonary vein (PV) lesion gaps were assessed by high-density electroanatomical mapping. Then, 24 patients (Group 2) underwent ICE-guided CBA and were compared with 25 patients who underwent conventional CBA (historical controls). In Group 1, there was a significant correlation between PLFV and electrical PV gap diameter (r=-0.715, P<0.001). PLFV was higher without than with an electrical gap (mean [±SD] 127.0±28.6 vs. 66.6±21.0 cm/s; P<0.001) and the cut-off value of PLFV to predict electrical isolation was 105.7 cm/s (sensitivity 0.700, specificity 0.929). In Group 2, ICE-guided CBA was successfully performed with acute electrical isolation of all PVs and without the need for "rescue" contrast injection. Atrial tachyarrhythmia recurrence at 6 months did not differ between ICE-guided and conventional CBA (3/24 [12.5%] vs. 5/25 [20.0%], respectively; P=0.973, log-rank test). CONCLUSIONS: PLFV predicted the presence of an electrical PV gap after CBA. ICE-guided CBA was feasible and safe, and could potentially be performed completely contrast-free without a decrease in ablation efficacy.

Predictor analysis of 1-year restenosis after percutaneous transluminal angioplasty for femoropopliteal stenotic lesions using intravascular ultrasound.

This retrospective, single-center study evaluated the patency rate and predictors of restenosis after percutaneous transluminal angioplasty (PTA) for femoropopliteal stenotic lesions using intravascular ultrasound. We assessed 78 de novo femoropopliteal stenotic lesions (64 patients; mean age, 73.6 ± 9.4 years; average lesion length, 59.8 mm) that underwent PTA under intravascular ultrasound guidance. The primary endpoint was 1-year primary patency. The 1-year primary patency rate was 63%. The frequency of insulin use was significantly greater (44% vs. 12%, p = 0.005), and lesions were significantly longer (77.8 mm vs. 49.2 mm, p = 0.047) in the restenosis group than in the non-restenosis group. The pre-intervention reference lumen area and minimum lumen area (MLA) were significantly smaller in the restenosis group (reference lumen area: 19.7 ± 6.7 mm2 vs. 23.7 ± 7.4 mm2, p = 0.017; MLA 3.9 ± 2.8 mm2 vs. 5.7 ± 3.9 mm2, p = 0.026; respectively). The MLA was significantly smaller and the maximum angle of dissection was significantly larger in the restenosis group (MLA 9.3 mm2 vs. 12.3 mm2, p = 0.013; maximum angle of dissection: 104.1° vs. 69.6°, p = 0.003; respectively) among post-intervention parameters. Multivariate analysis revealed that the independent predictors of 1-year restenosis were the large post-intervention maximum angle of dissection and insulin use. Per receiver operating curve analysis, the best cut-off value of the post-intervention maximum angle of dissection that predicted 1-year restenosis was 70.2° (sensitivity 72.4%, specificity 63.3%, area under the curve 0.70, p = 0.004). In conclusion, the 1-year primary patency rate after PTA for relatively short stenotic femoropopliteal lesions was 63%. The large post-intervention maximum angle of dissection, measured using intravascular ultrasound, and insulin use were independent predictors of restenosis after PTA.

Reduction in coronary microvascular resistance through cardiac resynchronization and its impact on chronic reverse remodelling of left ventricle in patients with non-ischaemic cardiomyopathy.

AIMS: Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronary circulation in non-ischaemic cardiomyopathy. We sought to examine the effects of cardiac resynchronization therapy (CRT) on coronary flow dynamics and left ventricular (LV) function. METHODS AND RESULTS: Twenty-two patients with non-ischaemic cardiomyopathy (New York Heart Association class, III or IV; LV ejection fraction, ≤35%; QRS duration, ≥130 ms) were enrolled. One week after implantation of the CRT device, coronary flow velocity and pressure in the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCx) were measured invasively, before and after inducing hyperemia by adenosine triphosphate administration, with two programming modes: sequential atrial and biventricular pacing (BiV) and atrial pacing in patients with LBBB or sequential atrial and right ventricular pacing in patients with complete atrioventricular block (Control). We assessed hyperemic microvascular resistance (HMR, mean distal pressure divided by hyperemic average peak velocity) and the relationship between the change in HMR and mid-term LV reverse remodelling. Hyperemic microvascular resistance was lower during BiV than during Control (LAD: 1.76 ± 0.47 vs. 1.54 ± 0.45, P < 0.001; LCx: 1.92 ± 0.42 vs. 1.73 ± 0.31, P = 0.003). The CRT-induced change in HMR of the LCx correlated with the percentage change in LV ejection fraction (R = -0.598, P = 0.011) and LV end-systolic volume (R = 0.609, P = 0.010) before and 6 months after CRT. CONCLUSION: Cardiac resynchronization therapy improves coronary flow circulation by reducing microvascular resistance, which might be associated with LV reverse remodelling.

Optical coherence tomography and histopathology assessment after implantation of first- and second-generation drug-eluting stents in a porcine coronary model.

BACKGROUND: This study directly compared optical coherence tomography (OCT) and histopathology for the assessment of vascular response to first- and second-generation drug-eluting stents. METHODS AND RESULTS: Sirolimus-, everolimus-, and biolimus-eluting stents (SES, EES, and BES, respectively) were randomly implanted into the coronary arteries of 12 porcine. OCT was conducted after implantation: at 1, 3, and 6 months; histopathology was assessed at 3 and 6 months. At 1-month OCT, EES had the highest neointimal area (NA) and lowest neointimal unevenness score (NUS). At 6 months, NA and NUS were equivalent among the stent types. ∆NA from 1 to 6 months was lowest for EES, and ∆NA correlated with the histopathological inflammation score at 6 months, which was highest for SES (P<0.001). The mean signal intensity (MSI) and the attenuation were different for the stent types at 3 months, and were associated with inflammation score. Moderate diagnostic efficiency for measuring MSI was found, with an optimal cut-off of 6.88 predicting a high (≥grade 3) inflammation score. CONCLUSIONS: EES had the greatest uniformity and the least neointimal proliferation and were associated with less persistent inflammation. OCT provides accurate morphometric data; furthermore, quantitative measurement of the optical properties may help assess histological inflammation, which was more predominantly associated with SES than with EES and BES.

Qualitative and quantitative assessment of stent restenosis by optical coherence tomography: comparison between drug-eluting and bare-metal stents.

BACKGROUND: We hypothesized that the tissue components of in-stent restenosis (ISR) might differ between drug-eluting stents (DES) and bare-metal stents (BMS) and that these differences could be distinguished by qualitative and quantitative optical coherence tomography (OCT) analyses. METHODS AND RESULTS: One-hundred and twenty-two initial ISR lesions (sirolimus-eluting stents: n=28; paclitaxel-eluting stents: n=51; BMS: n=43) were evaluated with OCT. Based on their OCT appearance, the lesions were classified as homogeneous, layered or heterogeneous. The optical properties of backscatter, attenuation and signal intensity of the neointimal tissue (NIT) were quantified. To evaluate the vascular response after balloon angioplasty (BA), the rate of reduction of the NIT area (NITA) was calculated (NITA before - after BA/NITA before BA at the minimum lumen cross-sectional area). Among the morphologic OCT patterns, the layered type was predominant with DES, whereas lesions were homogeneous with BMS (P<0.001). Backscatter and signal intensity were significantly higher with BMS (P<0.05 and P<0.001 respectively). The NITA reduction rate was significantly greater in the layered and heterogeneous groups than in the homogeneous group (P<0.01). CONCLUSIONS: The morphologic OCT patterns of the NIT in ISR differed significantly between DES and BMS, probably reflecting pathologic differences. Layered and heterogeneous tissues might respond better than homogeneous tissue to simple balloon dilatation, suggesting a possible direction for OCT-based ISR treatment strategies.

Impact of Medina classification on clinical outcomes of imaging-guided coronary bifurcation stenting.

Background: Intracoronary imaging improves clinical outcomes after stenting of complex coronary bifurcation lesions (CBLs), but the impact of Medina classification-based CBL distribution on outcomes of imaging-guided bifurcation stenting is unclear. Methods: In this integrated analysis of four previous studies, in which all CBLs were treated with drug-eluting stents under intravascular ultrasound or optical coherence tomography guidance, the distribution of 763 CBLs was assessed using angiographic Medina classification. Major adverse cardiac events (MACE), including target lesion revascularization (TLR), myocardial infarction, stent thrombosis, and cardiac death, were investigated at 1-year follow-up. Results: The most and least prevalent Medina subtypes were 0-1-0 (27.9 %) and 0-0-1 lesions (2.8 %). The most and least frequent MACE/TLR rates were 18.2 %/18.2 % for 0-0-1 lesions and 4.1 %/2.8 % for 0-1-0 lesions. Risks were higher for 0-0-1 lesions than for 0-1-0 lesions for both MACE (hazard ratio [HR]: 4.04, 95 % confidence interval [CI]: 1.21-13.45, p = 0.02) and TLR (HR: 6.19, 95 % CI: 1.69-22.74, p = 0.006). MACE rates were similar for true and non-true CBLs excluding 0-0-1 lesions (8.2 % and 5.9 %, HR 1.54, 95 % CI: 0.86-2.77, p = 0.15), while MACE (HR: 3.25, 95 % CI: 1.10-9.63, p = 0.03) and TLR (HR: 4.24, 95 % CI: 1.38-12.96, p = 0.01) risks were higher for 0-0-1 lesions. Conclusions: This integrated analysis of imaging-guided bifurcation stenting demonstrated similar clinical outcomes in true and non-true CBLs, except for 0-0-1 lesions, which had a significantly higher risk of MACE/TLR.

Serial changes of the side-branch ostial area after single crossover stenting with kissing-balloon inflation.

PURPOSE: We aimed to investigate the serial change of the side-branch ostial area (SBOA) depended on the wire-position before Kissing-balloon inflation (KBI) in the single-stent strategy for bifurcation lesions separately in the left main coronary artery (LMCA) and in non-LMCA. METHODS: Patients who underwent a single-stent KBI for a bifurcation lesion and had OCT images at the timing of the rewiring, at the post-procedure, and at the 9-month follow-up were extracted from the 3D-OCT Bifurcation Registry, which is a multicenter-prospective registry of patients with a percutaneous coronary intervention for a bifurcation lesion under OCT guidance. The SBOA was measured by dedicated software, and the rewiring position at the side-branch ostium after crossover stenting was assessed by three-dimensional-optical coherence tomography (3D-OCT). The optimal rewiring was defined as link-free-type and distal rewiring. The relationship between the optimal rewiring and the serial change of the SBOA was investigated separately in LMCA and non-LMCA cases. RESULTS: We examined 75 bifurcation lesions (LMCA, n = 35; non-LMCA, n = 40). The serial changes of the SBOA with the optimal rewiring were not significantly different regardless of LMCA and non-LMCA (LMCA:3.96 to 3.73 mm2, p = 0.38; non-LMCA:2.16 to 2.21 mm2, p = 0.98), whereas the serial changes of the SBOA with the sub-optimal rewiring were significantly reduced (LMCA:6.75 to 5.54 mm2, p = 0.013; non-LMCA:2.28 mm2 to 2.09 mm2, p = 0.024). There was no significant difference in clinical events between the optimal and sub-optimal rewiring group regardless of the LMCA and non-LMCA. CONCLUSION: The side-branch ostial area dilated with the optimal rewiring position in a bifurcation lesion treated with single crossover stenting and kissing-balloon inflation was preserved regardless of whether the bifurcation was in the LMCA or a non-LMCA.

Impact of stent platform of paclitaxel-eluting stents: assessment of neointimal distribution on optical coherence tomography.

BACKGROUND: The Taxus Express™ paclitaxel-eluting stent (Express-PES) and Taxus Liberté™ PES (Liberté-PES) have identical drugs, drug doses, and polymers, but different stent platforms. The Liberté-PES platform has thinner struts, specifically designed for more uniform drug elution. METHODS AND RESULTS: Fifty-four patients who underwent 6-month follow-up optical coherence tomography (OCT) after Express-PES (n=27) or Liberté-PES (n=27) implantation were enrolled. Longitudinal and circumferential uniformity of neointimal distribution was evaluated in 3-D by computing mean neointimal thickness (NIT) within 360 equally spaced radial sectors for every 1-mm cross-section. After stenting, intravascular ultrasound showed that Liberté-PES had a significantly smaller maximum angle between adjacent struts, with a tendency toward a lower incidence of % length of the segment with maximum angle >90° than Express-PES. Liberté-PES had a significantly thinner mean NIT than the Express-PES with comparable frequency of uncovered struts. Longitudinal and circumferential absolute variation of NIT expressed by standard deviation of NIT from each sector was significantly smaller for Liberté-PES than for Express-PES. Liberté-PES had a tendency toward a decreased incidence of thrombus and peri-strut low-intensity areas (findings suggestive of delayed arterial healing), compared to Express-PES. CONCLUSIONS: Stent design and thickness appeared to affect neointima suppression of PES. The stent platform of the Liberté-PES may offer greater and more homogeneous reduction of neointimal proliferation spatially across the full length of the PES.

Effect of cytochrome P450 2C19 polymorphism on target lesion outcome after drug-eluting stent implantation in japanese patients receiving clopidogrel.

BACKGROUND: Cytochrome P450 (CYP) 2C19 polymorphism is associated with reduced responsiveness to clopidogrel and poor clinical outcome after drug-eluting stent (DES) implantation, but its contribution to lesion outcome after DES implantation is unclear. METHODS AND RESULTS: The study included 160 Japanese patients who received clopidogrel and underwent DES implantation with follow-up angiography. Patients were divided into 3 groups by CYP2C19 polymorphism: extensive metabolizers (EM), intermediate metabolizers (IM), and poor metabolizers (PM). The incidence of major adverse cardiac events (MACE) and target lesion revascularization (TLR) were compared among the 3 groups. Optical coherence tomography (OCT) was performed for 120 patients to evaluate the incidence of intra-stent thrombi. Of the 160 patients, the proportion of EM, IM, and PM was 37.5%, 48.1%, and 14.4%, respectively. The incidence of TLR and MACE was more frequent in IM and PM than EM (TLR: 18.2% and 26.1% vs. 3.3%, P=0.008, MACE: 22.1% and 30.4% vs. 5.0%, P=0.005). Among the 120 patients who underwent follow-up OCT, intra-stent thrombi were more frequently detected in IM and PM than in EM (45.6% and 63.2% vs. 20.5%, P=0.005). The incidence of TLR was significantly higher in patients with than in those without intra-stent thrombi (27.7% vs. 6.8%, P=0.003). CONCLUSIONS: CYP2C19 loss-of-function polymorphism might be associated with the incidence of MACE and TLR in association with intra-stent thrombi.

Vascular healing after kissing balloon inflation: Nine-month 3D optical coherence tomography analysis in corelab.

Background: The jailing strut configuration with link-free and distal guidewire recrossing (LFD) at the side branch orifice (SBO) reduces incomplete stent apposition (ISA) after kissing balloon technique (KBT) in crossover stenting of coronary bifurcation lesions (CBLs). However, data regarding vascular healing after KBT are lacking. We investigated vascular healing 9 months after crossover stenting followed by KBT with optical coherence tomography (OCT) guidance in a prospective multicenter registry. Methods: Fifty-nine patients with CBLs (LFD, 35 patients; non-LFD, 24 patients) were studied. The jailing configuration of the SB and the wire-recrossing position, incidence of ISA and uncovered struts, and neointima unevenness score (NUS) in the main vessel (MV) after 9 months were determined by off-line 3D-OCT in the core laboratory. Results: The ISA rate was significantly higher at the SB ostium and distal MV after KBT in the non-LFD group, compared to the LFD group. After 9 months, incidence of ISA (18.3 ± 18.2 vs. 6.0 ± 8.7%, p < 0.01) and uncovered struts (8.7 ± 9.9 vs. 4.7 ± 7.3 %, p = 0.08) were higher at the SB ostium with higher SB restenosis in the non-LFD group. In distal MV, NUS was significantly higher (3.1 ± 1.1 vs. 2.5 ± 0.6, p < 0.05). In true-CBLs, an increase in uncovered struts and ISA rate was prominent in the proximal MV and opposite SB. No differences were observed in the 9-month clinical outcomes. Conclusion: Visualization of the wire recrossing point and the SB-jailing strut pattern by OCT plays an important role to optimize the KBT in CBL stenting, resulting in favorable mid-term vascular healing.

Outcomes of Dissection Angles as Predictor of Restenosis after Drug-Coated Balloon Treatment.

AIM: The predictors of restenosis after endovascular therapy (EVT) with paclitaxel drug-coated balloons (DCBs) have not been clearly established. The present study aimed to investigate the association of post-procedural dissection, as evaluated using intravascular ultrasound (IVUS), with the risk of restenosis following femoropopliteal EVT with paclitaxel DCBs. METHODS: In the present single-center retrospective study, 60 de novo femoropopliteal lesions (44 patients) that underwent EVT with DCBs, without bail-out stenting, were enrolled. The primary outcome was 1-year primary patency. Risk factors for restenosis were evaluated using a Cox proportional hazards regression model and random survival forest analysis. RESULTS: The 1-year primary patency rate was 57.2% [95% confidence interval, 45%-72%]. IVUS-evaluated post-procedural dissection was significantly associated with the risk of restenosis (P=0.002), with the best cutoff point of 64º [range, 39º-83º]. The random survival forest analysis showed that the variable importance measure of IVUS-evaluated dissection was significantly lower than that of the reference vessel diameter (P＜0.001), not different from that of the lesion length (P=0.41), and significantly higher than that of any other clinical feature (all P＜0.05). CONCLUSION: IVUS-evaluated post-procedural dissection was associated with 1-year restenosis following femoropopliteal EVT with DCB.

Efficacy of coronary imaging on bifurcation intervention.

During the coronary bifurcation intervention procedure, imaging including intravascular ultrasound and optical coherence tomography is essential to provide precise anatomy of the lesion and morphological information. This consensus document between the Korean Bifurcation Club and the Japanese Bifurcation Club summarizes practical guidelines and current evidences on lesion assessment, device selection, procedural guidance, and the optimization of bifurcation intervention by the imaging.

Efficacy of the proximal optimization technique on crossover stenting in coronary bifurcation lesions in the 3D-OCT bifurcation registry.

AIM: We sought to investigate the efficacy of the proximal optimization technique (POT) on crossover stenting followed by side branch (SB) dilation under optical coherence tomography guidance in a multicenter registry study. METHODS AND RESULTS: A total of 135 bifurcation lesions in 134 patients were divided into POT (n = 52) and non-POT groups (n = 83). The POT was performed before SB dilatation (pre-POT; n = 26), finally (final-POT; n = 12), at both timing (re-POT; n = 13), and uncertain (n = 1). There were no significant intergroup differences in the success rate of guide wire re-crossing (GWR) into the optimal cell (72% vs. 65%), incidence of the link-free type in the configuration of the SB jailed struts (51% vs. 49%), or incomplete strut apposition at the bifurcation (13 ± 11% vs. 10 ± 9%). However, insufficient stent expansion close to the carina in the proximal main vessel (MV) due to inappropriate POT was likely to induce greater incomplete strut apposition (ISA) around the bifurcation. Only re-POT provided more symmetric proximal MV expansion, while pre- and final-POT did not. CONCLUSION: The POT did not provide the expected beneficial effects, such as reduction of ISA or more optimal GWR, under the OCT guidance. Wide stent expansion in the proximal MV induced by the POT increased the likelihood of achieving optimal GWR, whereas symmetric stent expansion was provided by re-POT.

Techniques for reducing air bubble intrusion into the left atrium during radiofrequency catheter and cryoballoon ablation procedures: An ex vivo study with a high-resolution camera.

BACKGROUND: Air embolisms are serious complications during catheter ablation procedures. OBJECTIVES: The aims of the present study were to determine when air bubbles enter the left atrium (LA) during catheter ablation procedures and to identify techniques that reduce air bubble intrusion. METHODS: An ex vivo study was performed to monitor air bubbles using a silicone heart model and a high-resolution camera. In total, 280 radiofrequency catheter and cryoballoon ablation processes were tested. RESULTS: Small and large air bubbles were often observed during catheter ablation processes. Many small air bubbles arose during sheath flushing at fast speeds (15 mL/2 s) (median bubble number [quartiles]: 35 [20-53] for SL0, 35 [23-44] for Agilis, and 98 [91-100] for FlexCath) and during initial cryoballoon inflation/freezing/deflation (34 [22-47]). Large (≥1.5 mm) air bubbles were observed during Lasso catheter insertion (1 [0-1]), cryoballoon insertion (2 [1-2]), and initial inflation/freezing/deflation (1 [1-3]). Massive air bubbles were observed during Optima catheter insertion into the sheath using an inserter (10 [2-15]). Sheath flushing at slow speeds (15 mL/5 s) significantly reduced the number of air bubbles. Before cryoballoon insertion, temporary balloon inflation and air bubble removal from the inflated surface were most effective in reducing air bubble intrusions. Optima catheter insertion without an inserter significantly reduced large air bubble intrusion. CONCLUSION: Air bubbles entered the LA at specific times. Techniques such as sheath flushing at slow speeds, temporary cryoballoon inflation before insertion, inserting the Optima catheter without an inserter, and avoidance of negative pressure in the LA could reduce air bubble intrusion.

Feasibility and usefulness of three-dimensional optical coherence tomography guidance for optimal side branch treatment in coronary bifurcation stenting.

BACKGROUND: For the treatment of coronary bifurcation lesions, optimal guidewire (GW) recrossing after main vessel stenting is important for good stent apposition at the side branch (SB) orifice in kissing balloon inflation (KBI). METHODS: We analyzed 150 bifurcation lesions treated with single stenting following KBI in the three-dimensional optical coherence tomography (3D-OCT) bifurcation registry study (2015-16) and a single center experience (2012-16). OCT examination was performed after GW recrossing to the SB and after KBI. Patients were divided into two-dimensional (2D, n=78) and 3D groups (n=72) according to 2D- or 3D-OCT guidance. GW recrossing position, jailing configuration of the stent over the SB (divided into Link-connecting type: stent link connecting to the carina and Link-free type: no stent link at the carina) and stent apposition were compared between the groups. RESULTS: Distal GW recrossing was achieved in 75.6% and 91.7% in the 2D and 3D groups, respectively (P=0.004). Compared with the 2D group, the incidence of incomplete stent apposition (ISA) toward the SB in the 3D group tended to be lower in the whole cohort (14.5±13.6% vs 10.0±9.0%, P=0.077), and was significantly lower in left main trunk bifurcations (18.7±12.8% vs 10.3±8.9%, P=0.014). Independent contributors to ISA were the Link-connecting type (ß 0.089, P<0.001), distal GW recrossing (ß -0.078, P=0.001), and age (ß -0.0020, P=0.012). CONCLUSION: Optimal GW recrossing under 3D-OCT guidance is feasible and improves stent apposition, which may lead to a better clinical outcome in the treatment of bifurcation lesions.

Impact of guidewire recrossing point into stent jailed side branch for optimal kissing balloon dilatation: core lab 3D optical coherence tomography analysis.

AIMS: We aimed to investigate the influence of the guidewire recrossing point on the incidence of incomplete stent apposition (ISA) after kissing balloon dilatation (KBD), and also clinical and angiographic outcome at nine months in a prospective multicentre registry. METHODS AND RESULTS: One hundred and five patients underwent single crossover stenting across the side branch (SB) and subsequent KBD. The jailing configuration of the SB orifice and the guidewire recrossing position were assessed by off-line 3D-OCT in the core lab. We defined the cases that achieved both link-free carina configuration and distal recrossing as the LFD group (54 cases), and the other cases as the non-LFD group (51 cases). ISA in the LFD group was significantly smaller than that in the non-LFD group (6.7±5.9% vs. 17.0±10.5%, p<0.0001). The distal recrossing rate was 83%. Proximal recrossing increased ISA compared with distal recrossing, particularly in parallel bifurcations (17.1±10.1% vs. 6.3±6.0%, p<0.0001). At follow-up, though event rates did not differ, SB restenosis in the non-LFD group tended to be higher than in the LFD group (20.5% vs. 8.3%, p=0.1254). CONCLUSIONS: The guidewire recrossing point and the location of a stent link at the SB orifice had an influence on the ISA. KBD with optimal conditions under 3D-OCT guidance may reduce SB restenosis.