Proximal to Distal Y-Stent Deployment for Coronary Bifurcation Lesions: Procedure and Three-Year Clinical Outcomes.

AIMS: Percutaneous coronary intervention with Y-stenting of coronary bifurcation disease is not commonly undertaken. The procedural and medium-term clinical outcomes of coronary bifurcation lesions treated with the proximal to distal Y stent technique by a single experienced operator were reviewed. METHODS: A total of 167 consecutive procedures using either provisional Y strategies or full-coverage options performed at Auckland City Hospital, New Zealand, between January 2013 and July 2018 were included in this retrospective observational study. All medical records and coronary angiograms were reviewed. RESULTS: Three-year clinical follow-up data were available in 162 of 167 patients. The primary endpoint, defined as the composite of cardiovascular death, spontaneous myocardial infarction (MI), target-lesion revascularization (TLR), target-vessel nontarget-lesion revascularization (nontarget-lesion TVR), and stent thrombosis (ST) occurred in 25 patients (15%) at 3 years. Secondary endpoints were all-cause mortality (12%), including cardiovascular mortality (6%), noncardiovascular mortality (4%), undetermined death (2%), spontaneous MI (7%), TLR (1%), nontarget-lesion TVR (0%), and ST (0.6%). CONCLUSIONS: The proximal to distal Y-stent technique is a widely applicable approach to bifurcation lesions, with good medium-term clinical outcomes when used in a heterogeneous group of clinical and anatomical scenarios. Complications related to the stented site were infrequent. Randomized, controlled trials are needed to assess its efficacy compared with other bifurcation interventional techniques.

Real-time intravascular ultrasound guidance: A novel technique for accurate placement of ostial stents.

OBJECTIVES: To describe a novel technique for ostial stent placement using real-time IVUS guidance. BACKGROUND: Accurate placement of coronary stents at ostial locations is challenging with the true ostium frequently being missed increasing the risk of adverse events. We have developed a novel technique for ostial stent placement and report our benchtop testing and initial clinical experience. METHODS: Benchtop testing was performed to validate the appearance of the stent and delivery system on IVUS. Benchtop testing of real-time IVUS guided ostial stent positioning was carried out in a left main bifurcation phantom. Real-time IVUS guidance of stent placement in aorto-ostial, ostial left anterior descending (LAD), or ostial circumflex lesions was assessed in a prospective registry. RESULTS: Bench model IVUS demonstrated clear differences between the appearances of the stent and other components of the delivery system. Positioning of 10 consecutive stents into the ostial LAD using real-time IVUS guidance was assessed in a left main bifurcation model. Median distance from proximal stent edge to LAD ostium was 0.39 mm (interquartile range 0.31 to 0.73). Real-time IVUS guidance of ostial stent placement was performed in 50 patients (51 lesions). Angiographic success was 100%. IVUS post-stenting demonstrated median distance from the proximal stent edge to the ostium was 0.2 mm (interquartile range 0.1 to 0.5 mm). There was one periprocedural myocardial infarction but no other major adverse cardiac events at 30-days. CONCLUSIONS: We have developed a novel technique using real-time IVUS guidance allowing accurate ostial stent placement.

Proximal to distal Y-stenting for coronary bifurcation lesions using radial access: A modern bifurcation technique.

Proximal to distal Y stenting technique is a modified bifurcation technique based on the original Y stenting technique described over 20 years ago. We use a bench top model to illustrate the steps of the technique, which can provide both provisional and full coverage options, using radial artery access. This technique may be applied in clinical settings on a wide range of bifurcation anatomies with a number of unique advantages.

Critical aspects of balloon position during final proximal optimization technique (POT) in coronary bifurcation stenting.

OBJECTIVES: In a coronary bifurcation bench model, to determine the effects of side branch (SB) wire crossing position and balloon position on the stent scaffolding after the final proximal optimization technique (POT). BACKGROUND: POT performed as a final step after SB dilatation or kissing balloon inflation (KBI) has been widely advocated despite limited evidence. METHODS: Thirty-one stent implantations in bifurcation phantoms were performed using a one-stent provisional technique with (KBI) (n = 13), with POT-side-POT technique (n = 12) or with the two-stent culotte technique (n = 6). SB wiring was performed through either a proximal or a distal stent cell and confirmed by optical coherence tomography. Final POT was performed with the balloon positioned either across or proximal to the SB takeoff. The area of the opened stent cell in front of the SB was assessed by 3D reconstructed microcomputation tomography scans performed before and after Final POT. RESULTS: In cases with metallic carina, final POT across the SB takeoff caused SB rejailing. Regardless of stent technique and wire position, a Final POT across the SB takeoff reduced the SB cell opening area by 43% [32%;58%] (n = 15). The largest reduction (54-70%) was found after the POT-side-POT technique in procedures with a proximal wiring. Final POT performed proximal to the SB takeoff caused limited or no SB cell opening area reduction (4% [0.6%;6%] [n = 16]). CONCLUSION: Final POT with balloon positioned across the SB takeoff in a narrow angle bifurcation reduces largest stent cell area in front of the SB ostium and may cause SB rejailing in cases with metallic carina.

Mechanical properties of the drug-eluting bioresorbable magnesium scaffold compared with polymeric scaffolds and a permanent metallic drug-eluting stent.

OBJECTIVES: To compare on the bench the physical and mechanical properties of Magmaris, a magnesium bioresorbable scaffold (BRS), with Absorb and DESolve polymeric BRS and a permanent metallic stent. BACKGROUND: Understanding the mechanical and physical properties of BRS is crucial for appropriate implantation and postdilatation. METHODS: Testing was performed in fluid at 37°C and in silicone bifurcation phantoms with a 30° angle between main branch (MB) and side branch. RESULTS: The 3.0-mm Magmaris BRS did not fracture after MB postdilatation up to 4.4 mm in contrast to the Absorb where the safe postdilatation diameter was 3.7 mm. For dilatation through stent cells, there were no Magmaris fractures with 3.0-mm noncompliant (NC) balloons inflated to nominal pressure. Mini-kissing balloon postdilatation with two 3.0-mm NC balloons up to 17 atm was without fracture except for an outlier. Longitudinal and radial strengths were similar for Magmaris and Absorb BRS. The crossing profile for the Magmaris was larger than other devices. Recoil 120 min after deployment was the greatest for Magmaris but 120 min after 3.5 mm postdilatation all devices had similar diameters. CONCLUSIONS: The Magmaris BRS was more resistant to strut fracture than Absorb. It had a larger crossing profile than other devices and similar radial and longitudinal strengths to Absorb. While recoil after deployment was greater with Magmaris, 120 min after 3.5 mm postdilatation all devices had similar diameters.

Towards validating stent induced micro flow patterns in left main coronary artery bifurcations.

We investigated if blood flow changes induced through the presence of a stent could be detected using in vitro dynamically scaled 4D Phase-Contrast Magnetic Resonance Imaging (PC-MRI). Using idealized and patient-specific left main coronary artery bifurcations, we 3D-printed the dynamically large scaled geometries and incorporated them into a flow circuit for non-invasive acquisition with a higher effective spatial resolution. We tested the effects of using non-Newtonian and Newtonian fluids for the experiment. We also numerically simulated the same geometries in true scale for comparison using computational fluid dynamics (CFD). We found that the experimental setup increased the effective spatial resolution enough to reveal stent induced blood flow changes close to the vessel wall. Non-Newtonian fluid replicated all of the flow field well with a strong agreement with the computed flow field (R2 > 0.9). Fine flow structures were not as prominent for the Newtonian compared to non-Newtonian fluid consideration. In the patient-specific geometry, arterial non-planarity increased the difficulty to capture the near wall slow velocity changes. Findings demonstrate the potential to dynamically scale in vitro 4D MRI flow acquisition for micro blood flow considerations.

Rational and design of the European randomized Optical Coherence Tomography Optimized Bifurcation Event Reduction Trial (OCTOBER).

Background: Percutaneous coronary intervention in complex bifurcation lesions is prone to suboptimal implantation results and is associated with increased risk of subsequent clinical events. Angiographic ambiguity is high during bifurcation stenting, but it is unknown if procedural guidance by intravascular optical coherence tomography (OCT) improves clinical outcome. Methods and Design: OCTOBER is a randomized, investigator-initiated, multicenter trial aimed to show superiority of OCT-guided stent implantation compared to standard angiographic-guided implantation in bifurcation lesions. The primary outcome measure is a 2-year composite end point of cardiac death, target lesion myocardial infarction, and ischemia-driven target lesion revascularization. The calculated sample size is 1,200 patients in total, and allocation is 1:1. Eligible patients have stable or unstable angina pectoris or stabilized non­ST elevation myocardial infarction, and a coronary bifurcation lesion with significant main vessel stenosis and more than 50 % stenosis in a side branch with a reference diameter ≥2.5mm. Treatment is performed by the provisional side branch stenting technique or 2-stent techniques, and the systematic OCT guiding protocol is aimed to evaluate (1) plaque preparation, (2) lesion length, (3) segmental reference sizes, (4) lesion coverage, (5) stent expansion, (6) malapposition, (7) wire positions, and (8) ostial results. Implications: A positive outcome of the OCTOBER trial may establish OCT as a routine tool for optimization of complex percutaneous coronary intervention, whereas a negative result would indicate that OCT remains a tool for ad hoc evaluation in selected cases.

Relation between bioresorbable scaffold sizing using QCA-Dmax and long-term clinical outcomes in 1,232 patients from three study cohorts (ABSORB Cohort B, ABSORB EXTEND, and ABSORB II).

AIMS: This study sought to investigate the long-term clinical outcomes related to scaffold sizing based on quantitative coronary angiography. METHODS AND RESULTS: A total of 1,248 patients who received Absorb bioresorbable scaffolds in the ABSORB Cohort B, ABSORB EXTEND, and ABSORB II trials were included in the analysis. The incidence of MACE (a composite of cardiac death, any myocardial infarction [MI], and ischaemia-driven target lesion revascularisation [ID-TLR]) was analysed according to the Dmax subclassification of oversized scaffold group versus non-oversized (any undersize) scaffold group. At three years, event rates were similar in both groups in MACE (9.4% vs. 9.8%, p=0.847), target vessel MI (5.2% vs. 4.8%, p=0.795), and ID-TLR (4.8% vs. 5.8%, p=0.445). Landmark analysis after one year showed that the non-oversized scaffold group had higher rates of MACE (3.2% vs. 6.9%, log-rank p=0.004), target vessel MI (0.7% vs. 2.7%, log-rank p=0.007), and ID-TLR (2.5% vs. 4.7%, log-rank p=0.041). CONCLUSIONS: Implantation of an undersized scaffold was associated with a higher risk of MACE between one and three years, while in the previous report an oversized scaffold was associated with a higher risk of MACE up to one year. This implies different mechanisms for early and late events after scaffold implantation.

Transcatheter Aortic Valve Implantation In Patients With a Large Aortic Annulus.

BACKGROUND: As the indications for transcatheter aortic valve implantation (TAVI) have expanded, so to have the demands on interventionists to allow as many patients to access this technology as possible. METHODS: We retrospectively reviewed our TAVI database for patients who had received a 29mm SAPIEN 3 valve despite having an annular area greater than the manufacturer-recommended upper limit of 683mm2, as determined by multi-detector computed tomography (MDCT). Procedural and inpatient outcome data were collected. RESULTS: The study population was 5 of 121 patients receiving a SAPIEN 3 valve since it became available in March 2015. Their annular area ranged from 691 to 800mm2. Valve deployment was successful in all patients. The deployment balloon volume was nominal, except for an additional 1ml in one patient. No patient had a new indication for permanent pacing, and no significant valvular or paravalvular regurgitation (PVR) was identified on post-procedure transthoracic echocardiography. All patients survived to hospital discharge. CONCLUSIONS: In this select group of patients we have demonstrated that it is safe and feasible to use the 29mm SAPIEN 3 in patients with annular dimensions greater than those recommended, with minimal balloon overfilling.

Coronary balloon catheter tip damage. A bench study of a clinical problem.

OBJECTIVES: To confirm clinically that coronary balloon catheter tips may be damaged during bifurcation treatment with side-branch access through the side of a stent. On the bench, we aimed to assess the susceptibility of different balloon designs to damage. We compared catheter tip widths. We tested whether balloon tip flaring can cause stent distortion. BACKGROUND: We had observed that balloon catheters that failed to cross to a side-branch frequently exhibited tip damage. METHODS AND RESULTS: We examined microscopically for damage 82 balloon tips after clinical side-branch access. In a bench study, the forces required to compress catheter tips 0.5 mm were compared to assess susceptibility to damage. We compared tip widths of balloons of different nominal inflation diameters. We examined stents after side-branch access for distortion. In 42 of 48 (88%) of balloon tips from patients with resistance to or failure to cross through the side of a stent there was tip damage. Even when the balloon crossed without perceptible resistance, tip damage occurred in over half of balloons 18/34 (53%). Some balloon designs were more resistant to damage than others. Tips from balloons of different nominal diameters from the same manufacturer had the same width. Stent distortion caused by damaged balloon tips is improved by kissing balloon post-dilatation. CONCLUSIONS: Balloon tip damage is common with crossing between stent struts. This is one cause of failure of a balloon to access a side-branch and a new balloon should be used. If stent distortion is suspected, it should be corrected with kissing balloon post-dilatation.

Phase II randomized sham-controlled study of renal denervation for individuals with uncontrolled hypertension - WAVE IV.

OBJECTIVES: The aim of this double-blind, randomized, sham-controlled study was to verify the blood pressure (BP)-lowering efficacy of externally delivered focused ultrasound for renal denervation (RDN). BACKGROUND: Nonrandomized, first proof-of-concept study and experimental evidence suggested that noninvasive techniques of RDN emerged as an alternative approach of RDN to invasive technologies. METHODS: WAVE IV, an international, randomized (1 : 1) sham-controlled, double-blind prospective clinical study, was prematurely stopped. Patients were enrolled if office BP was at least 160 mmHg and 24-h ambulatory BP was at least 135 mmHg, while taking three or more antihypertensive medications. The treatment consisted of bilateral RDN using therapeutic levels of ultrasound energy and the sham consisted of bilateral application of diagnostic levels of ultrasound energy. RESULTS: In the 81 treated patients neither changes in office BP at 12 and 24 weeks, nor changes in 24-h ambulatory BP at 24-week follow-up visit differed between the two groups significantly. Of note, no safety signal was observed. Adherence analysis disclosed full adherence in 77% at baseline and 82% at 6 months' follow-up visit. Post hoc analysis revealed that stricter criteria for stabilization of BP at baseline were associated with a numerically greater change in 24-h ambulatory BP in the RDN group than in the sham group. CONCLUSION: Our data did not prove that antihypertensive efficacy of the externally delivered focused ultrasound for RDN was greater than the sham effect. Stabilization of BP at baseline was identified as an important determinant of BP changes.

Bench testing and coronary artery bifurcations: a consensus document from the European Bifurcation Club.

This is a consensus document from the European Bifurcation Club concerning bench testing in coronary artery bifurcations. It is intended to provide guidelines for bench assessment of stents and other strategies in coronary bifurcation treatment where the United States Food and Drug Administration (FDA) or International Organization for Standardization (ISO) guidelines are limited or absent. These recommendations provide guidelines rather than a step-by-step manual. We provide data on the anatomy of bifurcations and elastic response of coronary arteries to aid model construction. We discuss testing apparatus, bench testing endpoints and bifurcation nomenclature.

Long-term clinical outcomes of a crystalline sirolimus-eluting coronary stent with a fully bioabsorbable polymer coating: five-year outcomes from the DESSOLVE I and II trials.

AIMS: The aim of this study was to evaluate the five-year clinical results of a sirolimus-eluting stent (MiStent SES) with a bioabsorbable coating designed for sustained drug delivery during and after rapid polymer dissolution. METHODS AND RESULTS: The five-year results from the DESSOLVE I and II trials including major adverse cardiac events (MACE), target lesion failure (TLF), target vessel failure (TVF), and stent thrombosis (ST) at five-year follow-up are reported. In DESSOLVE I, 10.3% of patients receiving the MiStent SES (3/29) had a MACE event up to five years without TLF. In DESSOLVE II, 15.1% of patients in the MiStent group (18/119) had a five-year MACE event compared to 22.0% of patients in the Endeavor group (p=0.295). TLF was 9.2% in the MiStent group and 8.5% in the Endeavor group (p=1.00). TVF was 10.1% for MiStent versus 15.3% for Endeavor (p=0.331). Up to five-year follow-up, the MiStent SES has continued to demonstrate low rates of TLR across DESSOLVE I (0.0%) and DESSOLVE II (3.4%). No ST was reported with the MiStent up to five years in the DESSOLVE I trial. In DESSOLVE II, definite or probable ST was 0.0% with MiStent and 1.7% with Endeavor up to five years. CONCLUSIONS: The MiStent SES demonstrated long-term safety and effectiveness with low rates of five-year MACE, TLF, and TVF across these two clinical trials.

Effect of Technique on Outcomes Following Bioresorbable Vascular Scaffold Implantation: Analysis From the ABSORB Trials.

BACKGROUND: Procedural technique may affect clinical outcomes after bioresorbable vascular scaffold (BVS) implantation. Prior studies suggesting such a relationship have not adjusted for baseline patient and lesion characteristics that may have influenced operator choice of technique and outcomes. OBJECTIVES: This study sought to determine whether target lesion failure (TLF) (cardiac death, target-vessel myocardial infarction, or ischemia-driven target lesion revascularization) and scaffold thrombosis (ScT) rates within 3 years of BVS implantation are affected by operator technique (vessel size selection and pre- and post-dilation parameters). METHODS: TLF and ScT rates were determined in 2,973 patients with 3,149 BVS-treated coronary artery lesions from 5 prospective studies (ABSORB II, ABSORB China, ABSORB Japan, ABSORB III, and ABSORB Extend). Outcomes through 3 years (and between 0 to 1 and 1 to 3 years) were assessed according to pre-specified definitions of optimal technique (pre-dilation, vessel sizing, and post-dilation). Multivariable analysis was used to adjust for differences in up to 18 patient and lesion characteristics. RESULTS: Optimal pre-dilation (balloon to core laboratory-derived reference vessel diameter ratio ≥1:1), vessel size selection (reference vessel diameter ≥2.25 mm and ≤3.75 mm), and post-dilation (with a noncompliant balloon at ≥18 atm and larger than the nominal scaffold diameter, but not by >0.5 mm larger) in all BVS-treated lesions were performed in 59.2%, 81.6%, and 12.4% of patients, respectively. BVS implantation in properly sized vessels was an independent predictor of freedom from TLF through 1 year (hazard ratio [HR]: 0.67; p = 0.01) and through 3 years (HR: 0.72; p = 0.01), and of freedom from ScT through 1 year (HR: 0.36; p = 0.004). Aggressive pre-dilation was an independent predictor of freedom from ScT between 1 and 3 years (HR: 0.44; p = 0.03), and optimal post-dilation was an independent predictor of freedom from TLF between 1 and 3 years (HR: 0.55; p = 0.05). CONCLUSIONS: In the present large-scale analysis from the major ABSORB studies, after multivariable adjustment for baseline patient and lesion characteristics, vessel sizing and operator technique were strongly associated with BVS-related outcomes during 3-year follow-up. (ABSORB II Randomized Controlled Trial [ABSORB II]; NCT01425281; ABSORB III Randomized Controlled Trial [RCT] [ABSORB-III]; NCT01751906; A Clinical Evaluation of Absorb Bioresorbable Vascular Scaffold [Absorb BVS] System in Chinese Population-ABSORB CHINA Randomized Controlled Trial [RCT] [ABSORB CHINA]; NCT01923740; ABSORB EXTEND Clinical Investigation [ABSORB EXTEND]; NCT01023789; AVJ-301 Clinical Trial: A Clinical Evaluation of AVJ-301 [Absorb BVS] in Japanese Population [ABSORB JAPAN]; NCT01844284).

Long and short of optimal stent design.

The ideal stent must fulfil a broad range of technical requirements. Stents must be securely crimped onto the delivery balloon and, in this form, must have a low profile and be sufficiently flexible to facilitate deliverability to the lesion site without distortion or displacement. Following expansion, stents must exert sufficient radial force on the vessel wall to overcome lesion resistance and elastic recoil. To achieve an optimal lumen diameter, the lesion must be uniformly and adequately scaffolded, with minimal tissue prolapse between struts but without compromising side-branch access. Furthermore, the deployed stent must conform to the vessel curvature to minimise vessel distortion, particularly at the stent edges. Radio-opacity is also important to guide safe positioning, adequate deployment and postdilataion and to permit assessment of optimal stent expansion. Equally though, the stent lumen must also be sufficiently visible to allow radiographic assessment of flow dynamics and restenosis. Efforts to optimise one characteristic of stent design may have detrimental effects on another. Thus, currently available stents all reflect a compromise between competing desirable features and have subtle differences in their performance characteristics. Striving to achieve stents with optimal deliverability, conformability and radial strength led to a reduction in longitudinal strength. The importance of this parameter was highlighted by complications occurring in the real-world setting where percutaneous coronary intervention is often undertaken in challenging anatomy. This review focuses on aspects of stent design relevant to longitudinal strength.