Longitudinal Stent Deformation Research Articles

Longitudinal Stent Deformation at the Proximal Segment of the Left Main Coronary Artery Caused by a Stuck OCT Catheter: Case Report and Review of Literature.

It has been rarely reported that a stuck optical coherence tomography (OCT) catheter can lead to longitudinal stent deformation (LSD). This complication can result in incomplete stent apposition and dissection after stent implantation. In this study, we present a case where a bailout stent was implanted in the distal segment of the left anterior descending artery (LAD) after longitudinal stent deformation caused by a stuck OCT catheter. This approach was taken to prevent acute stent thrombosis, subacute stent thrombosis, in-stent restenosis (ISR), and death. The patients were followed up for one year, and no adverse events were observed.

Evaluation of post-dilatation on longitudinal stent deformation and postprocedural stent malapposition in the left main artery by optical coherence tomography (OCT): an in vitro study

BackgroundThe diameter of the ostial and proximal left main coronary artery can be greater than 5.0 mm. However, the diameters of the mostly available coronary drug-eluting stents (DESs) are ≤ 4.0 mm. Whether high-pressure dilatation can increase the diameter of stents from 4.0 to 5.0 mm and whether post-dilatation leads to longitudinal stent deformation (LSD) of 4.0-mm-diameter stents have rarely been studied. Therefore, this study aims to evaluate LSD and stent malapposition of six types of commercially available 4.0-mm-diameter stents in China in a 5.0-mm-diameter artificial blood vessel model by optical coherence tomography (OCT) in vitro.MethodsThe left main coronary artery was simulated by a truncated cone-shaped silicone tube. The internal diameters were 4.0 mm at one end of the silicone tube and 5.0 mm at the other end. Six different types of coronary stents widely used in China were selected for this study. Each stent was respectively implanted into the simulated blood vessel and dilated to a diameter of 4.2 mm according to the stent-balloon pressure compliance table. The stents were subjected to post-dilatation with a 5.0 × 15-mm noncompliant balloon. The LSD ratio of the longitudinal axis of each stent and stent malapposition were measured through OCT, and any fractures of the stents were determined.ResultsNone of the six types of stents fractured following post-dilatation. The longitudinal axes of the BuMA and Excrossal stents were slightly shortened, while the other stents were elongated after high-pressure post-dilatation. All stents expanded to a diameter of 5.0 mm without incomplete stent apposition, except for the Nano Plus stent, which remained malapposed after high-pressure post-dilatation.ConclusionAll 4.0-mm-diameter stents can be expanded to a diameter of 5.0 mm by noncompliant balloon post-dilatation without stent strut fracture. Most stents were found to be well apposed after high-pressure post-dilatation. However, LSD was observed after post-balloon dilatation. Stent malapposition might be positively correlated with the percentage change in stent length.

Bench test and in vivo evaluation of longitudinal stent deformation during proximal optimisation.

While radial stent deformation has been thoroughly investigated, data on longitudinal deformation are scarce. The aim of the study was to describe longitudinal stent deformation associated with the proximal optimisation technique (POT). Longitudinal stent deformation was assessed by bench testing and by clinical evaluation. Bench testing was performed in silicone models using 3.00 (n=15) and 3.50 mm (n=14) stent platforms. After deployment, stents were sequentially post-dilated in the proximal main branch up to 5.50 mm, in increments of 0.50 mm, in order to simulate a spectrum of overexpansion. Stent length was redefined by optical coherence tomography (OCT) after each step. Clinical data were collected retrospectively from OCT-guided bifurcation percutaneous coronary intervention cases. In bench tests, POT has led to significant stent elongation in all cases. The magnitude of elongation was comparable between the 3.00 and the 3.50 mm stent platforms, with 0.86±0.74 mm vs 0.86±0.73 mm, respectively (p=0.71), per 0.5 mm overexpansion. For 3.00 mm stent platforms, maximal elongation was 4.31±1.47 mm after up to 5.5 mm overexpansion. For 3.50 mm platforms, maximal elongation was 2.87±0.94 mm after up to 5.5 mm overexpansion. Thirty-six clinical cases were analysed, of which 22 (61%) were performed in the distal left main. Post-dilation was performed with 0.98±0.36 mm absolute overexpansion, resulting in 2.22±1.35 mm elongation, as compared to nominal stent length. Overexpansion by POT results in proximal stent elongation. This has to be considered once the stent length is selected and the stent is positioned, especially in the left main stem, where proximal overexpansion is marked and accurate ostial landing is critical.

TCTAP C-065 Longitudinal Stent Deformation Caused by Optical Coherence Tomography Pullback in Percutaneous Coronary Intervention

TCTAP C-065 Longitudinal Stent Deformation Caused by Optical Coherence Tomography Pullback in Percutaneous Coronary Intervention

In-stent restenosis and longitudinal stent deformation: a case report

BackgroundLongitudinal stent deformation (LSD) is an infrequent complication of percutaneous coronary intervention (PCI), and it may lead to catastrophic clinical outcomes. However, reports of cardiac adverse events associated with LSD are rare.Case presentationA 55-year-old man with chest pain was treated for a severe left anterior descending branch (LAD)-diagonal 1 (D1) bifurcation lesion by PCI with two stents in the proximal LAD. LSD occurred during the withdrawal of the trapped D1 wire. High-pressure balloon dilatation was performed in the deformed stent, and the end-angiographic appearance was acceptable, but no additional corrective measures were implemented. Ten months later, the patient represented with acute coronary syndrome. Severe in-stent restenosis (ISR) had suboccluded the proximal LAD, and optical coherence tomography (OCT) visualized multilayered stent struts protruding into the lumen at the compressed segment of the stent. Following complete apposition with balloon dilation, a drug-coated balloon (DCB) was used to avoid an additional permanent metallic layer. He remained angina free, and the angiographic result demonstrated no residual stenosis at the six-month follow-up. To our knowledge, this case demonstrates the first report of ISR triggered by LSD in patients treated with DCBs under the guidance of OCT.ConclusionsThe current report underscores the importance of awareness of LSD, and OCT seems to be the preferred modality to confirm complete apposition. If left without performing additional corrective measures, LSD may be associated with a risk of ISR. Complete apposition with balloon dilation followed by a DCB is a feasible treatment option.

Case Report: Case of Coronary Stent Longitudinal Deformation

AbstractThe foreshortening of a stent also known as longitudinal stent deformation (LSD) is a potential complication of present generation drug-eluting stents (DES) that had thin struts design, and it was most commonly reported in the everolimus-eluting Promus Element stent. However, there are limited reports of migration and dislodgement of a DES shortly after its deployment. So, we describe a case of a DES foreshortening 1 and half months after its deployment. While performing complex interventions, careful handling and gentle manipulation of procedure-related devices and use of imaging modalities such as optical coherence tomography, intravascular ultrasound, and adjunctive balloons for complete lesion cover and optimal stent apposition may significantly reduce the occurrence of LSD and related complications.

Impact of post-dilatation on longitudinal stent elongation: An in vitro study

ObjectivesTo evaluate whether balloon inflation for post-dilatation causes longitudinal stent deformation (LSD). Methods and resultsTwo stents, sized 2.5mm×28mm and 3.5mm×28mm (Nobori®, biodegradable polymer biolimus-eluting stent; Ultimaster®, biodegradable polymer sirolimus-eluting stent; Terumo Co., Tokyo, Japan), were deployed at nominal pressure in straight and tapered silicon vessel models. Then, post-dilatation was performed in two ways: dilatation from the distal (D-P group) or proximal (P-D group) side of the stent. Microscopic findings showed that the stents were elongated during every step of the procedure regardless of the post-dilatation method and type of vessel model. The D-P group showed linear elongation during each step of post-dilatation (straight model: 28.7±0.3mm vs. 29.9±0.3mm, p=0.002; tapered model: 28.0±0.1mm vs. 29.9±0.1mm, p<0.001). In contrast, in the P-D group, the most significant change was observed in the first step of post-dilatation and only slight changes were observed thereafter (straight model: 28.6±0.1mm vs. 29.5±0.1mm, p<0.001; tapered model: 28.2±0.1mm vs. 29.5±0.1mm, p<0.001). Optical frequency domain imaging analysis showed that the frequency of stent strut malapposition was positively correlated with the percentage change in stent length (r=0.74, p<0.0001). ConclusionLSD was observed during every step of post-dilatation in both the straight and tapered vessel models. However, some differences were observed between the D-P and P-D groups. Minimizing stent strut malapposition may reduce the risk of LSD.

Optical coherence tomography pullback short axis and long axis views confirming longitudinal stent deformation at the ostium

Optical coherence tomography pullback short axis and long axis views confirming longitudinal stent deformation at the ostium

Predictors and Long-Term Clinical Outcome of Longitudinal Stent Deformation: Insights From Pooled Analysis of Korean Multicenter Drug-Eluting Stent Cohort.

There are limited data on the frequency of and factors associated with quantitative coronary angiography (QCA)-defined longitudinal stent deformation (LSD) in various contemporary drug-eluting stents platforms. This study sought to evaluate the predictors of LSD and its long-term clinical implication. A patient-level pooled analysis was performed with 7350 lesions in 5871 patients treated with platinum-chromium-based everolimus-eluting stent (Promus Element), cobalt-chromium-based everolimus-eluting stent (Promus/Xience V), or cobalt-chromium-based zotarolimus-eluting stent (Endeavor Resolute). QCA was performed to analyze differences of stent length between immediate post-deployment and final post-procedure. Independent factors associated with LSD were identified. Clinical outcomes at 3 years were compared between those with and without QCA-based LSD. The frequency of QCA-based LSD was 1.12% (82 cases). Nine of these cases were angiographically overt. Left main or ostial lesion, bifurcation treatment with provisional side branch stenting or ballooning, additional downstream intervention of a distal lesion, intravascular ultrasound use, and adjunctive post-dilatation were independently associated with QCA-based LSD. The type of stent was not associated with QCA-based LSD. Rates of target lesion failure were nominally higher in lesions with QCA-based LSD than in those without (8.97% versus 5.88%; hazard ratio, 1.415; 95% confidence interval, 0.631-3.175; P=0.399). LSD is uncommon with contemporary drug-eluting stents, regardless of the type of stent platform. LSD is mainly associated with procedural factors, especially with additional downstream procedures which require the passage of devices through the stent. Careful manipulation of poststent imaging or procedural devices is required to prevent LSD. More data are needed to clarify the impact of LSD on clinical events.

Longitudinal deformation bench testing using a coronary artery model: a new standard?

ObjectivesTo compare susceptibility of five different stent platforms with longitudinal stent deformation (LSD) using a clinically relevant bench testing model simulating both short and long malapposed lengths.BackgroundRecent data suggest that...

Outcomes of patients treated with durable polymer platinum-chromium everolimus-eluting stents: a meta-analysis of randomised trials.

The durable polymer platinum-chromium everolimus-eluting stent (PtCr-EES) is a new-generation drug-eluting stent (DES) with a platinum-enriched metallic platform developed to improve the percutaneous treatment of patients with coronary artery disease. We sought to investigate the performance of durable polymer PtCr-EES versus other new-generation DES. We undertook a meta-analysis of trials in which patients receiving percutaneous coronary intervention (PCI) were randomly assigned to durable polymer PtCr-EES versus other new-generation DES (other DES). Primary efficacy and safety outcomes were target lesion revascularisation (TLR) and definite/probable stent thrombosis (ST), respectively. Secondary outcomes were myocardial infarction (MI), target vessel revascularisation (TVR), death, cardiac death and longitudinal stent deformation (LSD). A total of 11,036 patients in seven trials received a PCI with either durable polymer PtCr-EES (n=6,613) or other DES (n=4,423). This latter group comprised patients treated with biolimus- (n=325), cobalt-chromium everolimus- (n=1,940) or zotarolimus-eluting stents (n=2,158). After a median follow-up of 12 months (interquartile range 12-24), durable polymer PtCr-EES displayed a risk of TLR (odds ratio 0.98, 95% confidence interval [CI]: 0.75-1.29; p=0.90) and definite/probable ST (0.89 [0.55-1.45]; p=0.63) comparable to that of other DES. However, the durable polymer PtCr-EES was associated with a higher risk of LSD (12.05 [1.60-90.71], p=0.02) compared to other DES. There was no significant difference with regard to other secondary outcomes nor was there heterogeneity across trials. At one-year follow-up, the durable polymer PtCr-EES displays a performance comparable to that of other new-generation DES platforms.

Clinical and angiographic outcomes of axial stent deformations in unrestricted real world patient population.

Prior reports have suggested that the design of the Promus Element stent is prone to longitudinal stent deformation (LSD). However, little is known about the clinical and angiographic outcomes of Promus Element stent axial deformations when implanted in unrestricted coronary lesions. Two independent reviewers retrospectively evaluated the procedure steps of 961 Promus Element stent (833 de novo lesions in 494 consecutive patients) implanted in unrestricted coronary lesions, between February 2012 and March 2013, and compared the prevalence, predictors, and the mid-term clinical and angiographic outcomes between lesions with and without stent deformation. Fifteen stents (1.56%) with LSD were observed (95% confidence interval [CI]: 0.78-2.34%). The proximal edge of the stent was deformed in 13 stents (86.6%). Ostial stenting (Adjusted Odds ratio [OR]: 9; 95%CI: 2.27-33.3; P = 0.002), and bifurcation lesions (Adjusted OR: 3; 95%CI: 1.03-8.8; P = 0.04) were independently associated with the occurrence of stent deformation. LSD led to unplanned stenting in (53%, 8 of 15) of the deformed stents, which consumed larger contrast volume and longer fluoroscopy time. At 8-month follow-up, there was no significant difference in binary restenosis rate and target lesions revascularization between both groups (P = 0.98, and P = 0.56, respectively), while death occurred in six patients of the non-LSD group (1.36%, 6 of 440) and none in the LSD group. All patients of the LSD group had no major adverse clinical events at 8-month follow-up. Axial stent deformation in Promus Element platform is an infrequent event, occurs following manipulation of the interventional tools. Other than unplanned stenting, the LSD was not associated with any adverse clinical events at 8-month follow-up.

Coronary stent concertina in proximal left anterior descending artery: An unusual case

Since the emergence of stents, there has been persistent improvement in flexibility and deliverability of stents with modifications in its design and number of connectors. This has unfortunately created negative effect on longitudinal strength of stent resulting into a recently recognized and unaccustomed complication, longitudinal stent deformation (LSD). It is an abrupt shortening of the stent along its longitudinal axis, usually after deployment, due to various reasons. We present a case of LSD in Promus Element stent implanted at proximal left anterior descending artery. The stent shortening was about 25%–30% of its actual length. As this led to exposure of a part of lesion, it was successfully managed by overlapping another stent.

Effects of Metal Material Stent Design Parameters on Longitudinal Stent Strength

The longitudinal stent deformation (LSD) was usually caused by the external force in the blood vessel. The effects of metal material stent design parameters on the longitudinal stent strength (LSS) were studied using finite element method (FEA). A longitudinal stent compression model was developed and a rigid surface was used to compress the stent after stent deployment in coronary arteries. Results showed that the connector length, the strut amplitude and the curvature radius at the crown junctions influenced the LSS hardly. However, the number of connector played the most significant role in the LSS, and increasing the number of connectors can substantially improve the LSS, and the LSS of stent with four connectors was nearly three times than that of the stent with two connectors. For the shape of connector, the LSS of the S-stent, M-stent and L-stent were successively increased. With regard to the L-stent, increasing the width of connector can improve the LSS. Reasonably changing stent design parameters can effectively strengthen the LSS. Conclusions obtained from this paper can help surgeons to select appropriate stents and designers to optimize the stent design to reduce the LSD.

Impact of stent platform on longitudinal stent deformation: an in vivo frequency domain optical coherence tomography study.

Recently, longitudinal coronary stent deformation has been highlighted as a possible cause of drug-eluting stent failure. Although bench tests and in vivo studies have demonstrated difference in longitudinal stent strength among the stents with different platforms, its clinical impact is still unknown. Furthermore, it is unknown if modified stent platform favorably affect the incidence of stent deformation. The aim of this study was to investigate the longitudinal deformation of the everolimus-eluting stents (EES) with different stent platforms by using frequency domain optical coherence tomography (FD-OCT). Seventy-eight lesions treated with EES (Xience Prime: n=26, Promus element: n=29, Promus premier: n=23) were studied. After successful stent implantation, FD-OCT was performed and stent length was measured using three-dimensional reconstruction of the images in vivo. Percent longitudinal stent shortening (%SS) was defined as the in vivo stent length divided by nominal stent length. Longitudinal stent deformation was defined as %SS>10%. Patients' and procedural characteristics were similar among 3 EESs. There was no difference in mean %SS between Xience Prime, Promus Element and Promus Premier (1.0±5.8, 2.9±6.7 and 0.8±3.7%, p=0.322). Incidence of the longitudinal stent deformation was significantly higher in Promus Element than the other stents (0, 13.8 and 0%, p=0.028). Incidence of longitudinal stent deformation was different between EESs with different stent platforms. Stent material, stent design and/or stent delivery balloon may affect longitudinal stent deformation.

Clinical, angiographic and procedural characteristics of longitudinal stent deformation

Recently, longitudinal stent deformation (LSD) has been reported increasingly. Even though the reported cases included almost all stent designs, most cases were seen in the Element™ stent design (Boston Scientific, Natick, MA, USA). It is considered that stent design, lesion and procedural characteristics play a role in the etiology of LSD. Yet, the effect of LSD on long-term clinical outcomes has not been studied well. Element stents implanted between January 2013 and April 2015 in our hospital were examined retrospectively. Patients were grouped into two according to the presence of LSD, and their clinical, lesion and procedural characteristics were studied. Twenty-four LSD's were detected in 1812 Element stents deployed in 1314 patients (1.83 % of PCI cases and 1.32 % of all Element stents). LMCA lesions (16.7 % vs 1.6 %, p < 0.001), complex lesions (75 % vs 35.1 %, p < 0.001), bifurcation lesions (37.5 % vs 18.3 %, p = 0.017), ostial lesions (33.3 % vs 12.8 %, p = 0.003), using of extra-support guiding catheter (54.2 % vs 22.3 %, p < 0.001) and extra-support guidewire (37.5 % vs 16.2 %, p = 0.005) were found to be more frequent in cases with LSD than in cases without it. In addition, the number of stents, stent inflation pressure and the use of post-dilatation were significantly different between the two groups. Two patients had an adverse event during the follow-up period. LSD is a rarely encountered complication, and is more common in complex lesions such as ostial, bifurcation and LMCA lesions. The use of extra-support guiding catheter, extra-support guidewires and low stent inflation pressure increases the occurrence of LSD. Nevertheless, with increased awareness of LSD and proper treatment, unwanted long-term outcomes can be successfully prevented.

Did the use of the Guideliner V2TM guide catheter extension increase complications? A review of the incidence of complications related to the use of the V2 catheter, the influence of right brachiocephalic arterial anatomy and the redesign of the V3TM Guideliner and clinical outcomes

ObjectiveWe sought to investigate the incidence of complications associated with V2 Guideliner, understand the mechanisms and evaluate the impact of alterations made to the V3 Guideliner.MethodsRetrospective analysis of consecutive cases...

Longitudinal stent deformation as a cause of very late stent thrombosis: Optical coherence tomography images

Longitudinal stent deformation as a cause of very late stent thrombosis: Optical coherence tomography images

Computational Modelling of Multi-folded Balloon Delivery Systems for Coronary Artery Stenting: Insights into Patient-Specific Stent Malapposition.

Despite the clinical effectiveness of coronary artery stenting, percutaneous coronary intervention or "stenting" is not free of complications. Stent malapposition (SM) is a common feature of "stenting" particularly in challenging anatomy, such as that characterized by long, tortuous and bifurcated segments. SM is an important risk factor for stent thrombosis and recently it has been associated with longitudinal stent deformation. SM is the result of many factors including reference diameter, vessel tapering, the deployment pressure and the eccentric anatomy of the vessel. For the purpose of the present paper, virtual multi-folded balloon models have been developed for simulated deployment in both constant and varying diameter vessels under uniform pressure. The virtual balloons have been compared to available compliance charts to ensure realistic inflation response at nominal pressures. Thereafter, patient-specific simulations of stenting have been conducted aiming to reduce SM. Different scalar indicators, which allow a more global quantitative judgement of the mechanical performance of each delivery system, have been implemented. The results indicate that at constant pressure, the proposed balloon models can increase the minimum stent lumen area and thereby significantly decrease SM.

Abstract 13701: Impact of Stent Platform on Longitudinal Stent Deformation: an in vivo 3-dimensional Optical Coherence Tomography Study

Introduction: Recently, longitudinal coronary stent deformation has been highlighted as a possible cause of drug-eluting stent failure. Although bench tests and in-vivo studies have demonstrated difference in longitudinal stent strength among the stents with different platforms, its clinical impact is still unknown. The aim of this study was to investigate the longitudinal deformation of the everolimus-eluting stents (EES) with different stent platforms by using 3-dimensional frequency domain optical coherence tomography (3D FD-OCT). Methods: Fifty-nine lesions treated with EES (Xience Prime (CoCr-EES): n=28, Promus element (PtCr-EES): n=31) were studied. Stent length was measured by 3D FD-OCT. Percent longitudinal stent shortening (%SS) was defined as the longitudinally shortened stent length standardized by nominal stent length. Longitudinal stent deformation was defined as %SS &gt;10%. Results: Patients’ and procedural characteristics were similar between CoCr- and PtCr-EES. There was no difference in mean %SS between PtCr-EES and CoCr-EES (3.1±6.5 vs. 0.9±5.6%, p=0.197). However, incidence of longitudinal stent deformation was significantly higher in PtCr-EES than in CoCr-EES (16.1% vs 0%, p=0.026) (Figure). Conclusions: Incidence of longitudinal stent deformation was different between EESs with different stent platforms. Stent material, stent design and/or stent delivery balloon may affect longitudinal stent deformation.