Incidence of stent under-deployment as a cause of in-stent restenosis in long stents

Endovascular therapy in intermittent claudication: Impact of IVUS guidance on treatment decisions

Conservative therapy is favored over revascularization for patients with peripheral arterial disease (PAD) and intermittent claudication (IC) owing to the better long-term results. The adjunctive use of intravascular ultrasound (IVUS) significantly improves endovascular therapy. However, data on IVUS and IC is scarce. Therefore, the aim of this investigation was to determine the safety and efficacy of IVUS in patients with IC and to evaluate discrepancies compared to angiography and potential consequences for treatment.This was a single-center prospective cohort study. Twenty patients with IC and femoropopliteal disease eligible for endovascular therapy were enrolled. Procedural data and discrepancies between IVUS and angiography were recorded.In total, 30 lesions were treated. IVUS-based measurements yielded substantially higher reference vessel diameters (RVD) and lesion lengths compared to DSA alone (RVD: 5.37 ± 0.71 mm vs. 4.74 ± 0.63 mm, p<.001, lesion length: 62.4 ± 41.4 mm vs. 42.18 ± 30.2 mm, p<.001). In 24 of 30 lesions (80%), a significant discrepancy in RVD (defined as difference >0.5 mm) and lesion length (defined as >20 mm) was determined between IVUS and standard DSA. Subsequently, IVUS assessment led to upsizing in 14 of 30 lesions (47%) and downsizing in 3 of 30 lesions (10%). On average, IVUS led to the selection of considerably larger balloons (5.25 ± 0.62 vs. 4.74 ± 0.63, p<.004) and device length (78.97 ± 44.19 mm vs. 42.18 ± 30.2, p<.001). Serious adverse events did not occur. Technical success was achieved in all cases.IVUS is safe and provides advantages regarding the evaluation of IC by depicting RVD and lesion length more reliably than standard DSA. More precise assessment of lesions resulted in the use of significantly larger devices. · The safety and efficacy of IVUS are confirmed for the distinct cohort of patients with IC.. · IVUS provides advantages for the evaluation of IC by depicting RVD and lesion length more reliably than standard DSA.. · More precise assessment of stenoses resulted in the selection of significantly larger devices, hence suggesting substantial clinical impact.. Hartung V, Augustin AM, Gruschwitz P et al. Endovascular therapy in intermittent claudication: Impact of IVUS guidance on treatment decisions. Fortschr Röntgenstr 2024; DOI 10.1055/a-2379-8857.

Safety and efficacy results of percutaneous renal stent implantation in patients with acute coronary syndrome with ectatic and aneurysmatic coronary arteries

BACKGROUND

For the treatment of stenotic lesions developing in dilated coronary arteries, it is difficult to find an appropriately sized coronary stent given that the vessel diameter is too large. This poses a greater problem, especially in patients who require urgent intervention, such as acute coronary syndrome.

OBJECTIVE

We aimed to evaluate the efficacy and safety of renal stents implanted in ectatic/aneurysmatic coronary arteries in such patients.

METHODS

In total, 18 patients (renal stent group) who underwent renal stent implantation in ectatic/aneurysmatic coronary arteries requiring percutaneous coronary intervention (PCI) and 45 patients who underwent large-sized bare-metal coronary stent (BMCS) implantation (BMCS group) at our center were included in the study. The primary endpoints were MACE (myocardial infarction and cardiovascular mortality), and the secondary endpoints were restenosis and all-cause mortality.

RESULTS

In the study patients with a mean follow-up of 25.3 ± 14.6 months (1-48 months), the control coronary angiography duration was 24.6 ± 14.8 months for the renal stent group and 22.8 ± 15.7 months for the BMCS group (p = 0.06). The MACE was observed in 2 (11.1%) patients in the renal stent group and 4 (8.9%) patients in the BMCS group (HR: 1.39 (0.24-7.82), p = 0.70). The secondary composite outcome was identified in 4 (22.2%) patients in the renal stent group and 6 (13.7%) patients in the BMCS group (HR: 1.93 (0.53-6.91), p = 0.31). No significant differences in primary and secondary outcomes were noted between the groups.

CONCLUSION

Renal stents used during PCI in patients with acute coronary syndrome with ectatic/aneurysmatic coronary arteries have similar efficacy, and mid-term follow-up results those noted for BMCS. These findings support that renal stents can be used in ectatic and aneurysmatic coronary arteries when necessary.

CLINICAL TRIAL REGISTRATION

This study has been registered on ClinicalTrials.gov (NCT05410678).

Physiologic Assessment after Coronary Stent Implantation

The presence of myocardial ischemia is a prerequisite for the benefit of coronary revascularization. In the cardiac catheterization laboratory, fractional flow reserve and non-hyperemic pressure ratios are used to define the ischemia-causing coronary stenosis, and several randomized studies showed the benefit of physiology-guided coronary revascularization. However, physiology-guided revascularization does not necessarily guarantee the relief of ischemia. Recent studies reported that residual ischemia might exist in up to 15-20% of cases after angiographically successful percutaneous coronary intervention (PCI). Therefore, post-PCI physiologic assessment is necessary for judging the appropriateness of PCI, detecting the lesions that may benefit from additional PCI, and risk stratification after PCI. This review will focus on the current evidence for post-PCI physiologic assessment, how to interpret these findings, and the future perspectives of physiologic assessment after PCI.

MECHANICAL CHARACTERIZATION OF BRAIDED SELF-EXPANDING STENTS: IMPACT OF DESIGN PARAMETERS

In this paper, the mechanical performance of braided nitinol stents was systematically studied to provide guidelines for optimum stent designs. The influences of braiding patterns, braiding angles, wire diameters, and strand numbers on the mechanical behavior of the stent in terms of crimping strain, radial strength, longitudinal flexibility, and stability were characterized utilizing finite element method. Our results have shown that the two key design factors of braided stents are the braiding angle and wire diameter. A smaller braiding angle can increase radial stiffness and have better longitudinal flexibility and can maintain the stent stability. The wire diameter has less influence on the radial stiffness than the braiding angle, but the longitudinal flexibility is most sensitive to the wire diameter. The strand number is directly proportional to the radial stiffness and inversely proportional to the longitudinal flexibility. Compared to the classical crossing pattern, we have also proposed two patterns. These patterns have a minimal impact on the crimping and radial stiffness of stents, but the stent made from them are more flexible. Among three crossing patterns, it is interesting to see that the classical pattern is the most stable crossing pattern for stand numbers larger than 36, but it became the most unstable pattern at the strand number of 24. This work has shed light on the optimum design of braided stents.

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 non–ST 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.

Improved stent expansion with prolonged compared with short balloon inflation: A meta-analysis

BACKGROUND

Despite evidence from individual studies suggesting that prolonged inflation improves coronary stent expansion, relatively shorter inflation times are commonly employed in clinical practice.

METHODS

We performed an electronic search of PubMed, Web of Science, Cochrane, and CINAHL databases to retrieve outcome studies comparing prolonged versus short inflation times during stent deployment. Outcomes studied included minimal stent diameter (MSD) and minimal stent area (MSA). Standardized mean difference (SMD) was used to estimate the effect sizes for these continuous variables.

RESULTS

Seven studies with a total of 341 patients (415 lesions; mean age 67.6 years; 82% male) were included. Drug-eluting stents were used in 89 ± 15% of coronary lesions. Prolonged stent inflation was associated with increased minimal stent diameter (2.93 ± 0.34 mm vs. 2.72 ± 0.28 mm; SMD = 0.42; 95% CI 0.25-0.59; P < 0.001) and minimal stent area (5.99 ± 1.21 mm² vs. 5.17 ± 0.87 mm² ; SMD = 0.46; 95% CI 0.19-0.73; P = 0.001) compared with shorter duration stent inflation. This difference remained significant in sensitivity analyses that excluded studies with very prolonged inflation duration or multiple stent balloon inflations.

CONCLUSION

Despite differences in duration and methodology, prolonged stent inflation is associated with improved expansion compared with shorter duration. The effect of this optimization recommends randomized trials to determine whether long-term outcomes can be improved by this simple technical modification.

Optical coherence tomography to guide percutaneous treatment of coronary bifurcation disease

INTRODUCTION

Cardiovascular disease remains the most common cause of death worldwide. Enormous progress in the technology and applicability of percutaneous techniques to treat obstructive coronary heart disease has been made, and the number of percutaneous coronary interventions (PCI) is increasing. Coronary bifurcations are involved in a substantial number of PCIs and despite recent advances, bifurcation PCI remains a challenge in terms of immediate success and long-term outcome. Angiography has a limited capacity for showing important features of the 3 dimensional coronary vessel anatomy, position of stent struts and exact wire positions and is therefore suboptimal for guiding bifurcation PCI. Intracoronary optical coherence tomography (OCT) provides high resolution and the information gained during PCI is unprecedented compared with angiography guidance and intravascular ultrasound. Areas covered: This review will provide an overview of the use of OCT to guide bifurcation-PCI. Expert commentary: OCT is a promising guide for bifurcation-PCI at each individual step: from planning the strategy (provisional versus two-stent strategy), to guidance during PCI, and finally checking the interventional result. Until dedicated randomized trails are complete, we recommend OCT guidance for interventions in complex coronary bifurcation disease and for imaging when unexpected procedural events occur.

Recurrent in-stent restenosis, certainty of its origin, uncertainty about treatment

Treatment of recurrent in-stent restenosis is a real brainteaser for the interventional cardiologist who cannot resort to the guidelines to have indications about the type of treatment to be preferred. The use of intracoronary imaging may provide insights into the underlying mechanisms of this complication and use of drug-coated balloons may be a valid alternative and especially a thoughtful treatment when the repeated and perseverant use of drug-eluting stents clearly fails. In this setting, we present a review of the literature about this interesting topic, going deep into the heart of the problem, its origin and possible treatment options.

Assessment of coronary stent deployment using computer enhanced x-ray images-validation against intravascular ultrasound and best practice recommendations

OBJECTIVE

To investigate the accuracy of stent measurements using coronary x-ray angiograms with a computer based stent enhancement algorithm applied (StentBoost, SB). To derive recommendations for best practice when using such systems.

BACKGROUND

Computer enhancement algorithms allow better visualization of intracoronary stents to assist in ensuring adequate stent deployment. Factors that affect the accuracy of measurements taken on such systems are yet to be fully understood.

METHODS

We analysed stent deployment of 43 stents in 33 patients measuring minimum stent diameter and cross sectional area (CSA) using intravascular ultrasound (IVUS), SB enhanced x-ray images, and quantitative coronary angiography (QCA). We investigated if the use of two projections and method of calibration influenced correlation between IVUS and SB measurements.

RESULTS

Using two views and performing calibration via the guide catheter improved agreement between SB and IVUS measurements. For example, minimum stent diameter assessed with SB using one view and balloon markers for calibration produced a correlation coefficient, r, of 0.21, whereas using two views and the guide catheter for calibration increased agreement to r = 0.62. Relative measures of stent deployment, such as the ratio of minimum to maximum CSA, produced good correlation between IVUS and SB (r = 0.74).

CONCLUSIONS

When using the SB system, two projection angles should be used to image the stent. For absolute measurements, the guide catheter should be used for calibration purposes. Relative measures of stent size, which are probably sufficient for assessment of deployment, also give good agreement with similar measures on IVUS, and require no calibration.

Primary stent therapy for symptomatic intracranial atherosclerotic stenosis: 1-year follow-up angiographic and midterm clinical outcomes

OBJECT

The aim of this study was to report 1-year angiographic follow-up results and midterm clinical outcomes in patients with symptomatic intracranial atherosclerotic lesions treated with stent placement.

METHODS

Ten patients with ischemic symptoms referable to stenotic intracranial atherosclerotic arteries, with greater than 60% stenosis, underwent elective surgery in which a primary stent was placed. All patients underwent pretreatment (> or =1 week) combination oral antiplatelet (clopidogrel and aspirin) therapy and long-term (6-month) combination oral antiplatelet (clopidogrel and aspirin) therapy after stents were placed. The procedure involved selecting stents of the same size as the diameter of the target vessel and slowly inflating the balloon to its nominal pressure. One-year angiography and midterm clinical follow-up data were obtained. The stents were successfully placed in all patients without any perioperative complication. The mean preoperative stenosis rate of 81% decreased to 4% after the stent was placed. Nine patients who underwent follow-up angiography (one patient refused) at a mean of 12.3 months (range 10-19 months) had no changes in luminal diameter compared with the immediate postoperative luminal diameter. Luminal narrowing increased, from 15 to 38%, in one case in which there was comparatively greater residual stenosis (15%). No patient suffered new ischemic symptoms during a mean clinical follow-up period of 21 months (range 12-36 months).

CONCLUSIONS

Elective stent surgery can provide good angiographic and clinical midterm outcomes in patients with symptomatic intracranial atherosclerotic stenosis, and the procedure is associated with a high degree of technical success. Reassessment of these promising results is needed in a larger population and in a randomized prospective comparison study.