The influence of strut thickness and cell design on immediate apposition of drug-eluting stents assessed by optical coherence tomography

Rationale and design of a randomized controlled trial: The effect of intensive lipid-lowering therapy with PCSK9 inhibitor on endothelial-coverage of stent strut after percutaneous coronary intervention (PCI) for patients with acute coronary syndrome (ACS): Optical coherence tomography (OCT) study (PIECES-OCT study)

Background

For the patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI), dual antiplatelet therapy (DAPT) for at least 1 year is recommended in the guidelines to minimize the risk of stent thrombosis. Persistently uncovered stent strut means delayed neointima formation and extend the window of time in which the stent is prone to thrombosis. Previous studies showed that statins could improve post-stenting strut endothelial coverage for patients undergoing PCI. However, there are lack of evidences on whether early initiation of proprotein convertase subtilisin/Kexin type 9 monoclonal antibody (PCSK9mAb) after PCI in ACS patients can further improve the rate of stent strut coverage on the background of oral lipid-lowering therapy (LLT).

Methods

This is a single-center, randomized trial to enroll 36 patients undergoing PCI with a clinical diagnosis of non-ST-segment elevation ACS. The baseline level of low-density lipoprotein cholesterol (LDL-C) of these patients are between 1.4 mmol/L and 3.4 mmol/L. Patients will be assigned to intensive lipid-lowering therapy (LLT) with PCSK9mAb group and conventional LLT without PCSK9mAb group for 12 weeks in a clinical follow-up setting according to 1: 1 randomization. the rate of stent strut endothelial coverage by optical coherence tomography (OCT) examination at 12 weeks after enrollment between the groups will be compared.

Conclusion

This will be the first study to investigate changes in the rate of stent strut endothelial coverage under intensive LLT with PCSK9mAb by OCT examination in ACS patients undergoing PCI. The finding of this study will provide clinical evidence for future research about the hypothesis of a novel strategy of "intensive LLT (PCSK9mAb + statin ± ezetimibe) combined with shortened DAPT duration" for ACS patients undergoing PCI.Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: ChiCTR2200063395.

Post-Stent Optical Coherence Tomography Findings at Index Percutaneous Coronary Intervention - Characteristics Related to Subsequent Stent Thrombosis

BACKGROUND

The association between unfavorable post-stent optical coherence tomography (OCT) findings and subsequent stent thrombosis (ST) remains unclear. This study investigated the ST-related characteristics of post-stent OCT findings at index percutaneous coronary intervention (PCI).Methods and Results:Fifteen patients with ST onset after OCT-guided PCI (ST group) were retrospectively enrolled. Post-stent OCT findings in the ST group were compared with those in 70 consecutive patients (reference group) without acute coronary syndrome onset for at least 5 years after OCT-guided PCI. The incidence of acute myocardial infarction (AMI) was higher in the ST than reference group (60.0% vs. 17.1%, respectively; P=0.0005). The incidence of incomplete stent apposition (93.3% vs. 55.7%; P=0.0064), irregular protrusion (IP; 93.3% vs. 62.8%; P=0.0214), and thrombus (93.3% vs. 51.4%; P=0.0028) was significantly higher in the ST than reference group. The maximum median (interquartile range) IP arc was significantly larger in the ST than reference group (265° [217°-360°] vs. 128° [81.4°-212°], respectively; P<0.0001). In AMI patients, the incidence of a maximum IP arc >180° was significantly higher in the ST than reference group (100% vs. 58.3%, respectively; P=0.0265).

CONCLUSIONS

IP with a large arc was a significant feature on post-stent OCT in patients with ST.

Thin Strut CoCr Biodegradable Polymer Biolimus A9-Eluting Stents versus Thicker Strut Stainless Steel Biodegradable Polymer Biolimus A9-Eluting Stents: Two-Year Clinical Outcomes

Background

While thinner struts are associated with improved clinical outcomes in bare-metal stents (BMS), reducing strut thickness may affect drug delivery from drug-eluting stents (DES) and there are limited data comparing otherwise similar thin and thick strut DES. We assessed 2-year outcomes of patients treated with a thin strut (84–88um) cobalt-chromium, biodegradable polymer, Biolimus A9-eluting stent (CoCr-BP-BES) and compared these to patients treated with a stainless steel, biodegradable polymer, Biolimus A9-eluting stent (SS-BP-BES).

Methods

In total, 1257 patients were studied: 400 patients from 12 centres receiving ≥1 CoCr-BP-BES in the prospective Biomatrix Alpha registry underwent prespecified comparison with 857 patients who received ≥1 Biomatrix Flex SS-BP-BES in the LEADERS study (historical control). The primary outcome was major adverse cardiac events (MACE)—cardiac death, myocardial infarction (MI), or clinically driven target vessel revascularization (cd-TVR). Propensity analysis was used to adjust for differences in baseline variables and a landmark analysis at day-3 to account for differences in periprocedural MI definitions.

Results

MACE at 2 years occurred in 6.65% CoCr-BP-BES versus 13.23% SS-BP-BES groups (unadjusted HR 0.48 [0.31–0.73]; P=0.0005). Following propensity analysis, 2-year adjusted MACE rates were 7.4% versus 13.3% (HR 0.53 [0.35–0.79]; P=0.004). Definite or probable stent thrombosis, adjudicated using identical criteria in both studies, occurred less frequently with CoCr-BP-BES (1.12% vs. 3.22%; adjusted HR 0.32 [0.11–0.9]; P=0.034). In day-3 landmark analysis, the difference in 2-year MACE was no longer significant but there was a lower patient-orientated composite endpoint (11.7% vs. 18.4%; HR 0.6 [0.43–0.83]; P=0.006) and a trend to lower target vessel failure (5.8% vs. 9.1%; HR 0.63 [0.4–1.00]; P=0.078).

Conclusion

At 2-year follow-up, propensity-adjusted analysis showed the thin strut (84–88um) Biomatrix Alpha CoCr-BP-BES was associated with improved clinical outcomes compared with the thicker strut (114–120um) Biomatrix Flex SS-BP-BES.

Long-Term Clinical Outcomes of Late Stent Malapposition Detected by Optical Coherence Tomography After Drug-Eluting Stent Implantation

Background

The relationship between late stent malapposition (LSM) and adverse cardiovascular events is controversial. Studies are needed to evaluate long‐term (>5 years) clinical outcomes of LSM detected by optical coherence tomography (OCT) after drug‐eluting stent implantation.

Methods and Results

We investigated long‐term clinical outcomes of OCT‐detected LSM in 351 patients who received drug‐eluting stents and were examined by both poststent and follow‐up OCT (175±60 days after drug‐eluting stent implantation) from January 2009 to December 2011. LSM was observed in 99 patients (28%). We evaluated the cumulative rate of composite events (cardiovascular death, target‐vessel–related myocardial infarction, target‐vessel revascularization, and stent thrombosis). During 80.1±24.5 months of follow‐up, very late stent thrombosis did not occur in any patients with LSM. The cumulative 8‐year rate of composite events was 7.3% in patients with LSM and 10.5% in patients without LSM (P=0.822, log‐rank test). We further divided patients into the following 4 groups: patients with both late‐persistent and late‐acquired stent malapposition (n=23), patients with late‐persistent stent malapposition alone (n=45), patients with late‐acquired stent malapposition alone (n=31), and patients without LSM (n=252). The cumulative 8‐year rates of composite events were similar among these 4 groups (0%, 9.6%, 9.7%, and 10.5%, respectively; P=0.468 by log‐rank test).

Conclusions

During long‐term follow‐up (>5 years), very late stent thrombosis did not occur in patients with OCT‐detected LSM. The rates of adverse clinical events were similar between patients with LSM versus those without LSM. Presence of OCT‐detected LSM was not associated with unfavorable clinical outcomes.

See Editorial by Ali et al

The "Oculo-Appositional Reflex": Should Optical Coherence Tomography-Detected Stent Malapposition Be Corrected?

See Article by Im et al

Meta-Analysis of the Impact of Strut Thickness on Outcomes in Patients With Drug-Eluting Stents in a Coronary Artery

The aim of this network meta-analysis is to assess the impact of strut thickness on clinical outcomes in patients who underwent percutaneous coronary intervention. We searched Medline/PubMed and performed a Bayesian network meta-analysis to compare outcomes of patients who underwent percutaneous coronary intervention with drug-eluting stents (DES) of different strut thicknesses (ultrathin 60 to 80 μm; thin 81 to 100 μm; intermediate 101 to 120 μm; thick ≥120 μm). Studies comparing DES with similar strut thickness, bare metal stents, and fully bioresorbable scaffolds were excluded. Odds ratios with credible intervals (OR [CrIs]) were generated with random-effects models to compare outcomes. Our primary end point was stent thrombosis (ST). We identified 69 RCTs including 80,885 patients (ultrathin group = 10,219; thin group = 36,575; intermediate group = 11,399; thick group = 22,692). Mean age was 64 ± 11 years and 75% were male gender. When compared with thick-strut DES, ultrathin struts had significant less ST and myocardial infarction (OR 0.43 [CrI 0.27 to 0.68]; and OR 0.73 [CrI 0.62 to 0.92], respectively). Sensitivity analysis including only studies with permanent polymer DES gave similar results. Improvement in DES technology with thinner struts is associated with significant reduction in ST and myocardial infarction compared with thicker struts.

Comparison of the vessel healing process after everolimus-eluting stent and bare metal stent implantations in patients with ST-elevation myocardial infarction

Cobalt-chromium everolimus-eluting stent (CoCr EES) is associated with a lower rate of stent thrombosis even in patients with ST-elevation myocardial infarction (STEMI). However, the time-serial changes of endothelial coverage of the stent struts in the extremely early period have never been reported, especially in patients with STEMI. The aim of this study was to compare the vessel healing process between CoCr EES and cobalt-chromium bare metal stent (CoCr BMS) implantations using optical coherence tomography (OCT) in patients with STEMI. Sixty-three patients who had primary emergent percutaneous coronary intervention (PCI) with CoCr EES (42 patients) or CoCr BMS (21 patients) were enrolled in this study for 3 years. OCT was performed just after, 2 and 12 weeks after EES or BMS implantations. Time-serial changes in the neointimal coverage (NIC), the neointimal thickness, and malapposition of stent struts were evaluated. NIC of stent struts did not differ between CoCr EES (23.2%, 99.4%) and CoCr BMS (24.0%, 97.8%) at 2 weeks and 12 weeks after PCI, respectively. Thicknesses of the neointima on the stent strut was significantly thinner in CoCr EES (34.0 ± 13.8, 107.0 ± 32.4 µm) than in CoCr BMS (40.0 ± 14.6, 115.7 ± 33.8 µm) at 2 weeks and 12 weeks after PCI (p = 0.011, p = 0.008), respectively. The malapposition did not differ just after PCI, and was completely resolved at 12 weeks after PCI in both groups. Thrombus was significantly less in CoCr EES than in CoCr BMS at 2 weeks (19.0% vs 42.9%, p < 0.01), and decreased over time in both groups, but at 12 weeks, disappeared only in CoCr EES (CoCr EES: 0% vs. CoCr BMS: 4.8%, p = 0.56). This study demonstrated that NIC and apposition of the stent struts almost completed at 12 weeks after EES and BMS implantations, while the neointimal thickness on the stent struts were thinner in EES than in BMS. Moreover, thrombus was significantly less in EES than in BMS implantations 2 weeks after PCI, which may explain the lower rate of acute and subacute stent thrombosis of EES compared with BMS.

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.

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

OBJECTIVES

To evaluate whether balloon inflation for post-dilatation causes longitudinal stent deformation (LSD).

METHODS AND RESULTS

Two 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).

CONCLUSION

LSD 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.

Current status and future direction of biodegradable metallic and polymeric vascular scaffolds for next-generation stents

Because of the increasing incidence of coronary artery disease, the importance of cardiovascular stents has continuously increased as a treatment of this disease. Biodegradable scaffolds fabricated from polymers and metals have emerged as promising materials for vascular stents because of their biodegradability. Although such stent framework materials have shown good clinical efficacy, it is difficult to decide whether polymers or metals are better vascular scaffolds because their properties are different. Therefore, there are still obstacles in the development of biodegradable vascular scaffolds in terms of improving clinical efficacy. This review analyzes the pros and cons of current stent materials with respect to five key factors for next-generation stent and discusses methods of improvement. Furthermore, we discuss biodegradable electronic stents with electrical conductivity, which has been considered unimportant until now, and highlight electrical conductivity as a key factor in the development of next-generation stents.

SYNTAX Score and Pre- and Poststent Optical Coherence Tomography Findings in the Left Anterior Descending Coronary Artery in Patients With Stable Angina Pectoris

SYNTAX score (SS) has been reported to be an independent predictor of future cardiac events including target lesion revascularization. The aim of this study was to assess the relation between SS and plaque characteristics and poststent vascular response using optical coherence tomography in coronary artery tree and left anterior descending artery (LAD) in patients with stable angina. A total of 179 lesions among 165 patients, including 100 lesions in LAD, were analyzed. Patients were stratified into tertiles. In pre-percutaneous coronary intervention analysis of whole coronary tree and LAD, lesions of the third tertile had the highest prevalence of lipid-rich plaque. Compared with the first tertile, the third tertile had greater lipid index, thinner fibrous cap, and higher prevalence of thin-cap fibroatheroma. In poststent optical coherence tomography, the incidence of stent edge dissection and irregular protrusion was higher in the third tertile compared with the first tertile in coronary tree analysis. In LAD analysis, the prevalence of irregular protrusion was the highest in the third tertile. In conclusion, high SS may reflect higher plaque vulnerability. Stent edge dissection and irregular protrusion were more frequent in patients with higher SS, indicating poor vascular response to stenting. Our results may explain higher cardiac event rate and target lesion revascularization in patients with higher SS.

Optical coherence tomography evaluation of tissue prolapse after carotid artery stenting using closed cell design stents for unstable plaque

BACKGROUND AND PURPOSE

During carotid artery stenting (CAS) with the use of closed cell design stents for unstable plaques, tissue prolapse between stent struts was evaluated by optical coherence tomography (OCT).

METHODS

14 carotid stenosis lesions diagnosed as unstable plaques by MRI were evaluated by OCT imaging during CAS using closed cell stents. Cross sectional OCT images within the stented segment were evaluated at 1 mm intervals. The slice rate for the presence of tissue prolapse between the struts was calculated.

RESULTS

No intra-procedural complications occurred. After single stent placement, plaque prolapse was observed in all cases. Slices with any and >500 µm tissue prolapse were seen in 30% and 7.8% of cases, respectively. In 5 of 7 lesions with tissue prolapse >500 µm, additional stents were overlapped. In cases with overlapping stents, slices with any tissue prolapse were significantly decreased from 26% to 16% (p=0.008); in particular, the occurrence of tissue prolapse >500 µm was significantly decreased from 15% to 2.3% (p<0.001). In one case of >500 µm tissue prolapse without an overlapping stent, delayed embolization due to an in-stent thrombus occurred 9 months after the procedure.

CONCLUSIONS

OCT during CAS using closed cell stent for unstable plaques frequently revealed tissue prolapse between struts. Placement of overlapping stents significantly reduced tissue prolapse, particularly tissue prolapse >500 µm. However, closed cell stents used for unstable plaques may not solve the problem of tissue prolapse.

Computational fluid dynamics study of common stent models inside idealised curved coronary arteries

The haemodynamic behaviour of blood inside a coronary artery after stenting is greatly affected by individual stent features as well as complex geometrical properties of the artery including tortuosity and curvature. Regions at higher risk of restenosis, as measured by low wall shear stress (WSS < 0.5 Pa), have not yet been studied in detail in curved stented arteries. In this study, three-dimensional computational modelling and computational fluid dynamics methodologies were used to analyse the haemodynamic characteristics in curved stented arteries using several common stent models. Results in this study showed that stent strut thickness was one major factor influencing the distribution of WSS in curved arteries. Regions of low WSS were found behind struts, particularly those oriented at a large angle relative to the streamwise flow direction. These findings were similar to those obtained in studies of straight arteries. An uneven distribution of WSS at the inner and outer bends of curved arteries was observed where the WSS was lower at the inner bend. In this study, it was also shown that stents with a helical configuration generated an extra swirling component of the flow based on the helical direction; however, this extra swirl in the flow field did not cause significant changes on the distribution of WSS under the current setup.

Serial optical coherence tomography assessment of malapposed struts after everolimus-eluting stent implantation. A subanalysis from the HEAL-EES study

BACKGROUND

Incomplete stent apposition (ISA) is related to stent thrombosis, which is a serious adverse event. We aim to assess the time-course of ISA after 2nd generation everolimus-eluting stent (EES) implantation.

METHODS

In HEAL-EES study, we enrolled 36 patients who underwent percutaneous coronary intervention (PCI) with EES. OCT imaging was performed at baseline and follow-up. Patients were randomized 1:1:1 into 3 groups according to the time in which follow-up was performed: group A (6-month), group B (9-month), and group C (12-month). In this subanalysis, patients who had ISA segments at baseline and/or follow-up OCT were analyzed.

RESULT

At baseline, among 41 lesions in 36 patients, 20 lesions in 18 patients had ISA segments and were analyzed. At baseline, there were 3.0% ISA struts in group A (n=8), 2.8% in group B (n=4), and 4.5% in group C (n=8). At follow-up, ISA struts were present in 0.09%, 0.16% and 0.64%; respectively in groups A, B, and C. At follow-up, there was a significant decrease in the frequency of ISA: group A 3.0% vs. 0.09% (p<0.001), group B 2.8% vs. 0.16% (p<0.001), and group C 4.5% vs. 0.64% (p<0.001). In group A, there was one late acquired ISA at follow-up.

CONCLUSIONS

In patients undergoing 2nd generation EES implantation, area of acute ISA assessed by OCT, was almost resolved at 6-month follow-up.

Optical Coherence Tomography Guided Percutaneous Coronary Intervention With Nobori Stent Implantation in Patients With Non-ST-Segment-Elevation Myocardial Infarction (OCTACS) Trial: Difference in Strut Coverage and Dynamic Malapposition Patterns at 6 Months

BACKGROUND

Incomplete strut coverage has been documented an important histopathologic morphometric predictor for later thrombotic events. This study sought to investigate whether optical coherence tomography (OCT)-guided percutaneous coronary intervention with Nobori biolimus-eluting stent implantation in patients with non-ST-segment-elevation myocardial infarction would provide improved strut coverage at 6 months in comparison with angiographic guidance only.

METHODS AND RESULTS

One hundred patients were randomized 1:1 to either OCT-guided or angio-guided Nobori biolimus-eluting stent implantation. Postprocedure OCT was performed in all patients. In the OCT-guided group, prespecified criteria indicating additional intervention were related to (1) stent underexpansion, (2) strut malapposition, (3) edge dissection(s), and (4) residual stenosis at the distal or proximal reference segment(s). A final OCT was performed in case of reintervention. Six-month OCT follow-up was available in 85 patients. Twenty-three (46%) OCT-guided patients had additional postdilation or stenting. The percentage of acutely malapposed struts was substantially lower in the OCT-guided group (3.4% [interquartile range, 0.3-7.6] versus 7.8% [interquartile range, 2.3-19.4]; P<0.01). At 6-month follow-up, the OCT-guided group had a significantly lower proportion of uncovered struts; 4.3% [interquartile range, 1.2-9.8] versus 9.0% [interquartile range, 5.5-14.5], P<0.01. Furthermore, OCT-guided patients had significantly more completely covered stents: 17.5% versus 2.2%, P=0.02. The percentages of malapposed struts and struts being both uncovered and malapposed at follow-up were comparable between groups.

CONCLUSIONS

OCT-guided optimization of Nobori biolimus-eluting stent implantation improves strut coverage at 6-month follow-up in comparison with angiographic guidance alone.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02272283.

Optical coherence tomography to evaluate coronary stent implantation and complications

Coronary optical coherence tomography (OCT) is now an established imaging technique in many catheterization laboratories worldwide. With its near-histological view of the vessel wall and lumen interface, it offers unprecedented imaging quality to improve our understanding of the pathophysiology of atherosclerosis, plaque vulnerability, and vascular biology. Not only is OCT used to accurately detect atherosclerotic plaque and optimize stent position, but it can further characterize plaque composition, quantify stent apposition, and assess stent tissue coverage. Given that its resolution of 15 μm is well above that of angiography and intravascular ultrasound, OCT has become the invasive imaging method of choice to examine the interaction between stents and the vessel wall. This review focuses on the application of OCT to examine coronary stents, the mechanisms of stent complications, and future directions of OCT-guided intervention.

Incidence and Morphological Predictors of Intrastent Coronary Thrombus After Drug-Eluting Stent Implantation (from a Multicenter Registry)

The mechanisms responsible for late and very late stent thrombosis remain incompletely understood. This study aimed to evaluate the incidence and morphologic predictors of intrastent thrombus in patients after drug-eluting stent (DES) implantation using optical coherence tomography (OCT). A total of 208 patients with 262 DES who underwent follow-up OCT examination >6 months after DES implantation were included. The detailed vascular morphology including characteristics of neointima was analyzed. Thrombus was identified in 24 patients (11.5%) 11 months after DES implantation. Minimal lumen cross-sectional area was significantly smaller in the thrombus group than in the nonthrombus group (2.9 ± 1.7 vs 4.6 ± 2.0 mm(2); p <0.001). No difference was found in the frequency of uncovered or malapposed struts between the 2 groups. Thin-cap fibroatheroma (20.6% vs 0.1%; p <0.001) and heterogeneous neointima (22.2% vs 9.0%; p = 0.001) were more frequently detected in the thrombus group compared to the nonthrombus group. Second-generation DES showed lower incidence of thrombus, uncovered struts, and extrastent lumen compared with first-generation DES. In conclusion, the present OCT study revealed that smaller lumen cross-sectional area and neointimal morphology are important factors associated with intrastent thrombus. Second-generation DES demonstrated improved arterial healing and a lower incidence of intrastent thrombus compared with first-generation DES.

Impact of Coronary Plaque Characteristics on Late Stent Malapposition after Drug-Eluting Stent Implantation

PURPOSE

To evaluate the impact of pre-procedural coronary plaque composition assessed by virtual histology intravascular ultrasound (VH-IVUS) on late stent malapposition assessed by optical coherence tomography (OCT) following drug-eluting stent (DES) implantation.

MATERIALS AND METHODS

The study population consisted of 121 patients (121 lesions) who underwent both pre-procedural VH-IVUS and follow-up OCT after DES implantation. The association between pre-procedural plaque composition [necrotic core (NC), dense calcium (DC), fibrotic (FT), and fibro-fatty (FF) volumes] assessed by VH-IVUS and late stent malapposition (percent malapposed struts) or strut coverage (percent uncovered struts) assessed by follow-up OCT was evaluated.

RESULTS

Pre-procedural absolute total NC, DC, FT, and FF plaque volumes were 22.9±19.0, 7.9±9.6, 63.8±33.8, and 16.5±12.4 mm³, respectively. At 6.3±3.1 months post-intervention, percent malapposed and uncovered struts were 0.8±2.5% and 15.3±16.7%, respectively. Pre-procedural absolute total NC and DC plaque volumes were positively correlated with percent malapposed struts (r=0.44, p<0.001 and r=0.45, p<0.001, respectively), while pre-procedural absolute total FT plaque volume was weakly associated with percent malapposed struts (r=0.220, p=0.015). Pre-procedural absolute total DC plaque volume was the only independent predictor of late stent malapposition on multivariate analysis (β=1.12, p=0.002). There were no significant correlations between pre-intervention plaque composition and percent uncovered struts.

CONCLUSION

Pre-procedural plaque composition was associated with late stent malapposition but not strut coverage after DES implantation. Larger pre-procedural absolute total DC plaque volumes were associated with greater late stent malapposition.

Incidence and Clinical Significance of Poststent Optical Coherence Tomography Findings

Background—

Optical coherence tomography (OCT) was recently introduced to optimize percutaneous coronary intervention. However, the exact incidence and significance of poststent OCT findings are unknown.

Methods and Results—

A total of 900 lesions treated with 1001 stents in 786 patients who had postprocedure OCT imaging were analyzed to evaluate the incidence of poststent OCT findings and to identify the OCT predictors for device-oriented clinical end points, including cardiac death, target vessel–related myocardial infarction, target lesion revascularization, and stent thrombosis. Patients were followed up to 1 year. Stent edge dissection was detected in 28.7% of lesions, and incomplete stent apposition was detected in 39.1% of lesions. The incidences of smooth protrusion, disrupted fibrous tissue protrusion, and irregular protrusion were 92.9%, 61.0%, and 53.8%, respectively. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm 2 in a drug-eluting stent or <5.6 mm 2 in a bare metal stent, was observed in 40.4% of lesions. One-year device-oriented clinical end points occurred in 33 patients (4.5%). Following adjustment, irregular protrusion and small minimal stent area were independent OCT predictors of 1-year device-oriented clinical end points ( P =0.003 and P =0.012, respectively).

Conclusions—

Abnormal poststent OCT findings were frequent. Irregular protrusion and small minimal stent area were independent predictors of 1-year device-oriented clinical end points, which were primarily driven by target lesion revascularization.

Impact of technological developments in drug-eluting stents on patient-focused outcomes: a pooled direct and indirect comparison of randomised trials comparing first- and second-generation drug-eluting stents

AIMS

To establish whether technological improvements in drug-eluting stent (DES) technology introduced in second-generation (G2) DES have contributed to improving patient-focused outcomes.

METHODS AND RESULTS

We performed a systematic review of randomised clinical trials (RCT) comparing first-generation (G1) and G2 DES with a>9-month clinical follow-up. The primary endpoint for efficacy was ischaemia-driven target lesion revascularisation (ID-TLR); safety endpoints were all-cause death, myocardial infarction (MI) and stent thrombosis (ST). Sixteen RCTs involving 25,427 patients met eligibility criteria (17 comparisons). In these trials, paclitaxel (PES) and sirolimus (SES) were compared with everolimus (EES), zotarolimus (ZES) or biolimus A9 (BES) DES. G2 varied in metal alloy, strut thickness and type of drug-eluting matrix. Overall, G2 DES were associated with a 26% relative risk reduction (RRR) of MI (relative risk [RR]=0.74, 95% CI: 0.61-0.90, p=0.003) and ST (RR=0.70, 95% CI: 0.55-0.89, p=0.004), while no significant benefit was observed for ID-TLR and death. Use of 2G DES was associated with a significant reduction in the risk of ID-TLR (RR=0.66, 95% CI: 0.51-0.85, p=0.002), MI (RR=0.60, 95% CI: 0.49-0.72, p<0.001) and ST (RR=0.41, 95% CI: 0.26-0.65, p=0.001) when compared with PES. Strut thickness ≤91 µm in G2 DES was associated with a significantly lower risk of MI (RR=0.54, 95% CI: 0.51-0.86, p=0.002).

CONCLUSIONS

The introduction of thinner stent struts and other technological improvements made in G2 DES technology have translated into better patient outcomes. Overall, the net benefit of G2 DES over G1 DES is expressed in terms of ID-TLR and ST risk reduction but it could be masked by heterogeneities in the use of G1 comparators and the use of non-inferiority study designs in RCTs.

3D optical coherence tomography: new insights into the process of optimal rewiring of side branches during bifurcational stenting

AIMS

We describe three-dimensional optical coherence tomography (3D-OCT) guided bifurcation stenting and the clinical utility of 3D-OCT.

METHODS AND RESULTS

Twenty-two consecutive patients who underwent OCT examination to confirm the recrossing position after stent implantation in a bifurcation lesion were enrolled. Frequency domain OCT images were obtained to check the recrossing position and 3D reconstructions were performed off-line. The recrossing position was clearly visualised in 18/22 (81.8%) cases. In 13 cases, serial 3D-OCT could be assessed both before and after final kissing balloon post-dilation (FKBD). We divided these cases into two groups according to the presence of the link between hoops at the carina: free carina type (n=7) and connecting to carina type (n=6). All free carina types complied with the distal rewiring. The percentage of incomplete stent apposition (%ISA) of free carina type at the bifurcation segment after FKBD was significantly smaller than that of the connecting to carina type (0.7±0.9% vs. 12.2±6.5%, p=0.0074).

CONCLUSIONS

3D-OCT confirmation of the recrossing into the jailed side branch is feasible during PCI and may help to achieve distal rewiring and favourable stent positioning against the side branch ostium, leading to reduction in ISA and potentially better clinical outcomes.

Sustained Efficacy and Arterial Drug Retention by a Fast Drug Eluting Cross-Linked Fatty Acid Coronary Stent Coating

The long held assumption that sustained drug elution from stent coatings over weeks to months is imperative for clinical efficacy has limited the choice for stent coating materials. We developed and evaluated an omega-3 fatty acid (O3FA) based stent coating that is 85% absorbed and elutes 97% of its Sirolimus analog (Corolimus) load within 8d of implantation. O3FA coated stents sustained drug levels in porcine coronary arteries similarly to those achieved by slow-eluting durable coated Cypher Select Plus Stents and with significantly lower levels of granuloma formation and luminal stenosis. Computational modeling confirmed that diffusion and binding constants of Corolimus and Sirolimus are identical and explained that the sustained retention of Corolimus was facilitated by binding to high affinity intracellular receptors (FKBP12). First in man outcomes were positive-unlike Cypher stents where late lumen loss drops over 6 month, there was a stable effect without diminution in the presence of O3FA. These results speak to a new paradigm whereby the safety of drug eluting stents can be optimized through the use of resorbable biocompatible coating materials with resorption kinetics that coincide with the dissociation and tissue elimination of receptor-bound drug.

Large platelets but not putative endothelial progenitor cells are associated with low strut coverage after drug-eluting stent implantation

OBJECTIVES

This study assessed whether different subsets of circulating endothelial and putative endothelial progenitor cells (CEC and EPC) correlate with stent strut coverage (SSC) using second generation optical coherence tomography (OCT).

BACKGROUND

Due to the lack of imaging modalities with a resolution down to the magnitude of a few cells, the influence of EPC on endothelialisation of drug-eluting stents has not been assessed in patients.

METHODS

In 37 patients, SSC of everolimus-eluting stents was assessed by OCT 5-7months after stent implantation. Different subsets of EPC (CD34(+)KDR(+), CD34(+)KDR(+)CD45(dim), CD133(+), CD3(+)CD31(+)), CEC (CD31(+)CD45(-)CD146(+)), and CD31(+)CD45(-)CD146(-) representing large platelets were analysed by flow cytometry, including viability analyses with 7-AAD. Statistical analysis comprised univariate regression analysis and multivariable models integrating OCT and flow cytometry data as well as clinical variables.

RESULTS

SSC and frequency of different cell types were highly comparable with previously published data. EPC defined in part by KDR expression were mostly non-viable. On univariate and in multivariable models, no association between EPC counts and strut coverage was detected. For CD31(+)CD45(-)CD146(-) counts, representing large platelets, an inverse relationship with strut coverage was identified by a multivariable regression model adjusting for age, sex, diabetes mellitus, NYHA and CCS class, CRP, serum triglycerides, glucose and creatinine (beta=-9.42, p=0.006).

CONCLUSIONS

There was no significant association between EPC or CEC and healing after drug-eluting stent implantation. Yet, CD31(+)CD45(-)CD146(-) cells were associated with low SSC. These data suggest that large platelets may represent a more important mediator of late stent endothelialisation than EPC.

ABSORB biodegradable stents versus second-generation metal stents: a comparison study of 100 complex lesions treated under OCT guidance

OBJECTIVES

The aim of this study was to compare the acute performance of the PLLA ABSORB bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) with second-generation metal drug-eluting stents (DES) in complex coronary artery lesions.

BACKGROUND

Thick polymer-based BVS have different mechanical properties than thin second-generation DES. Data on the acute performance of BVS are limited to simple coronary lesions treated in trials with strict inclusion criteria.

METHODS

Fifty complex coronary lesions (all type American College of Cardiology/American Heart Association B2-C) treated with a BVS undergoing a final optical coherence tomography (OCT) examination were compared with an equal number of matched lesions treated with second-generation DES. The following stent performance indexes were assessed with OCT: mean and minimal area, residual area stenosis (RAS), incomplete strut apposition (ISA), tissue prolapse, eccentricity index, symmetry index, strut fracture, and edge dissection.

RESULTS

One hundred lesions from 73 patients were analyzed. A higher balloon diameter/reference vessel diameter ratio was used for predilation in the BVS group (p < 0.01). Most of the BVS and DES were post-dilated with short noncompliant (NC) balloons of similar diameter. OCT showed in the BVS group a higher tissue prolapse area (p = 0.08) and greater incidence of ISA at the proximal edge (p = 0.04) with no difference in the overall ISA. The RAS was 20.2% in the BVS group and 21.7% in the DES group (p = 0.32). There was no difference in the eccentricity index. The minimal and mean lumen areas were similar in the 2 groups. Two cases of strut fractures occurred after the BVS, whereas none was observed in the DES.

CONCLUSIONS

Based on OCT, the BVS showed similar post-procedure area stenosis, minimal lumen area, and eccentricity index as second-generation DES. The different approach for lesion preparation and routine use of OCT guidance during BVS expansion may have contributed to these results.

Intracoronary optical coherence tomography: a review of clinical applications

Optical coherence tomography (OCT) is a light-based technology that provides very high spatial resolution images. OCT has been initially employed as a research tool to investigate plaque morphology and stent strut coverage. The introduction of frequency domain OCT allowing fast image acquisition during a prolonged contrast injection via the guiding catheter has made OCT applicable for guidance of coronary interventions. In this manuscript, the various applications of OCT are reviewed, from assessment of plaque vulnerability and severity to characteristics of unstable lesions and thrombus burden to stent optimization and evaluation of late results.

Impact of statin treatment on strut coverage after drug-eluting stent implantation

PURPOSE

To evaluate the effect of statin treatment on strut coverage after drug-eluting stent (DES) implantation.

MATERIALS AND METHODS

In this study, 60 patients were randomly assigned to undergo sirolimus-eluting stent (SES) or biolimus-eluting stent (BES) implantation, after which patients were randomly treated with pitavastatin 2 mg or pravastatin 20 mg for 6 months. The degree of strut coverage was assessed by 6-month follow-up optical coherence tomography, which was performed in 52 DES-implanted patients.

RESULTS

The percentages of uncovered struts were 19.4±14.7% in pitavastatin-treated patients (n=25) and 19.1±15.2% in pravastatin-treated patients (n=27; p=0.927). A lower percentage of uncovered struts was significantly correlated with a lower follow-up low-density lipoprotein (LDL) cholesterol level (r=0.486; p=0.009) and a greater decline of the LDL cholesterol level (r=-0.456; p=0.015) in SES-implanted patients, but not in BES-implanted patients. In SES-implanted patients, the percentage of uncovered struts was significantly lower among those with LDL cholesterol levels of less than 70 mg/dL after 6 months of follow-up (p=0.025), but no significant difference in this variable according to the follow-up LDL cholesterol level was noted among BES-implanted patients (p=0.971).

CONCLUSION

Lower follow-up LDL cholesterol levels, especially those less than 70 mg/dL, might have a protective effect against delayed strut coverage after DES implantation. This vascular healing effect of lower LDL cholesterol levels could differ according to the DES type.

Randomised comparison of strut coverage between Nobori biolimus-eluting and sirolimus-eluting stents: an optical coherence tomography analysis

AIMS

The aims of this study were to compare strut tissue coverage at six-month follow-up after Nobori biolimus-eluting stent (N-BES) versus sirolimus-eluting stent (SES) implantation.

METHODS AND RESULTS

A total of 120 patients with a single stenotic lesion requiring revascularisation were randomly assigned to either N-BES (n=60) or SES (n=60). Baseline optical coherence tomography (OCT) was performed post stent implantation, and follow-up OCT was scheduled at six months. Post-intervention and follow-up OCT analyses were available in 51 (85.0%) and 52 (86.7%) patients, respectively. The primary endpoint was the percentage of uncovered struts at follow-up OCT in all cross-sections with analysis of 0.2 mm longitudinal intervals. In addition, an OCT contour plot analysis was constructed to investigate the distribution patterns of uncovered struts. The percentage of uncovered struts of N-BES was significantly lower versus SES (15.9±12.2% versus 25.1±18.3%, respectively, p=0.003). N-BES showed a greater NIH thickness than SES (median [interquartile range] 52.4 μm [41.9-74.9] versus 42.1 μm [30.6-56.0], p=0.005). Contour plot analyses showed a lower incidence of a diffuse distribution pattern of uncovered struts (46.8% versus 75.0%, respectively, p=0.022).

CONCLUSIONS

This randomised OCT study showed that N-BES had a significantly lower percentage of uncovered struts, and less common diffuse distribution pattern of uncovered struts versus SES.

Randomized comparison of acute stent malapposition between platinum-chromium versus cobalt-chromium everolimus-eluting stents

No randomized data exist regarding optical coherence tomography (OCT) evaluation immediately post-procedure and at the 3-month follow-up for platinum-chromium everolimus-eluting stents (PtCr-EES) versus cobalt-chromium everolimus-eluting stents (CoCr-EES). A total of 100 patients were randomly assigned to undergo PtCr-EES (n = 51) or CoCr-EES (n = 49) implantation. OCT was serially evaluated after stent deployment with nominal pressure and immediately post-procedure, and 3-month follow-up. The primary endpoint was the percentage of malapposed strut after nominal pressure and immediately post-procedure. Compared to the CoCr-EES, the PtCr-EES showed a lower tendency of percent malapposed strut at nominal pressure [median value (interquartile range); 4.1 % (0.5-11.7) vs. 7.6 % (2.9-13.7), p = 0.082] and immediately post-procedure [1.2 % (0-3.4) vs. 2.5 % (0.7-5.3), p = 0.051]. The percentage of cross sections with any malapposed struts was significantly lower with PtCr-EES at nominal pressure [15.0 % (5.6-39.0) vs. 23.8 % (18.2-44.4), p = 0.036] and immediately post-procedure [6.5 % (0-15.3) vs. 10.5 % (7.1-20.0), p = 0.026]. At the 3-month follow-up, both PtCr-EES and CoCr-EES showed comparable percentages of malapposed struts (0 vs. 0 %, respectively, p = 0.332) and uncovered struts (5.3 vs. 4.7 %, respectively, p = 0.829). We found a significant correlation between the immediate post-procedural percentage of malapposed struts versus the percentage of uncovered struts (r = 0.430, p < 0.001) at the 3-month follow-up. Compared to the CoCr-EES, the PtCr-EES shows a lower tendency toward a lower percentage of malapposed struts but no significant difference in strut coverage at the 3-month follow-up. The percentage of malapposed struts immediately post-procedure was correlated with strut coverage at the 3-month follow-up.

The relationship between post-stent strut apposition and follow-up strut coverage assessed by a contour plot optical coherence tomography analysis

OBJECTIVES

This study sought to evaluate the relationship between post-stent strut apposition and follow-up strut coverage using contour plot optical coherence tomographic analysis.

BACKGROUND

Tracking the fate of interested regions of struts at different time points has not been investigated.

METHODS

Post-intervention and 6-month follow-up optical coherence tomographic evaluations were performed in 82 patients treated with biolimus- (n = 37) or sirolimus-eluting stents (n = 45). Post-stent apposition was classified as embedded, apposed, or malapposed. For volumetric stent evaluation, the post-intervention strut-artery distance and the neointimal thickness at follow-up were measured as a function of the circumferential arc length and longitudinal stent length. Computer-generated contour plots of the strut-artery distance and neointimal thickness were compared.

RESULTS

The percentages of embedded and malapposed struts after intervention were 1.8% (Interquartile range [IQR]: 0.6% to 6.2%) and 2.3% (IQR: 0.5% to 5.2%), respectively. The percentages of uncovered and malapposed struts at 6 months were 16.0% (IQR: 7.4% to 33.3%) and 0% (IQR: 0% to 0.7%), respectively. The percentage of uncovered struts at 6 months varied significantly with post-stent strut apposition (0% [IQR: 0% to 11.4%] in embedded, 16.3% [IQR: 8.1% to 31.3%] in apposed, and 26.8% [IQR: 0% to 56.3%] in malapposed, p < 0.001 for all pairwise comparisons). In lesions without tissue prolapse, embedded struts were all covered (100% covered struts) compared with those with tissue prolapse (76.8% covered, p < 0.001).

CONCLUSIONS

The optical coherence tomography-guided optimization of stent strut apposition enhances strut coverage at follow-up. This comprehensive method for evaluating strut apposition may provide more useful information to understanding the serial changes in strut coverage. (Neointimal Coverage After Implantation of Biolimus Eluting Stent With Biodegradable Polymer: Optical Coherence Tomographic Assessment According to the Treatment of Dyslipidemia and Hypertension and the Types of Implanted Drug-Eluting Stents; NCT01502904).

Biodegradable polymer Biolimus-eluting stent (Nobori®) for the treatment of coronary artery lesions: review of concept and clinical results

First-generation drug-eluting stents have raised concerns regarding the risk of late and very late stent thrombosis compared with bare metal stents and require prolonged dual antiplatelet therapy. Despite extensive investigations, the physiopathology of these late events remains incompletely understood. Aside from patient- and lesion-related risk factors, stent polymer has been cited as one of the potential causes. In fact, the persistence of durable polymer after complete drug release has been shown to be responsible for local hypersensitivity and inflammatory reactions. Third-generation drug-eluting stents with more biocompatible or biodegradable polymers have subsequently been developed to address this problem. In this article, we evaluate and discuss the concept and clinical results (safety and efficacy) of a third-generation drug-eluting stent with biodegradable polymer: the Nobori® stent.

Mechanisms, pathophysiology, and clinical aspects of incomplete stent apposition

Incomplete stent apposition (ISA) is characterized by the lack of contact of at least 1 stent strut with the vessel wall in a segment not overlying a side branch; it is more commonly found in drug-eluting stents than bare-metal stents. The accurate diagnosis of ISA, initially only possible with intravascular ultrasound, can currently be performed with higher accuracy by optical coherence tomography, which also enables strut-level assessment due to its higher axial resolution. Different circumstances related both to the index procedure and to vascular healing might influence ISA occurrence. Although several histopathology and clinical studies linked ISA to stent thrombosis, potential selection bias precluded definitive conclusions. Initial studies usually performed single time point assessments comparing overall ISA percentage and magnitude in different groups (i.e., stent type), thus hampering a comprehensive understanding of its relationship with vascular healing. Serial intravascular imaging studies that evaluated vascular response heterogeneity recently helped fill this gap. Some particular clinical scenarios such as acute coronary syndromes, bifurcations, tapered vessels, overlapping stents, and chronic total occlusions might predispose to ISA. Interventional cardiologists should be committed to optimal stent choices and techniques of implantation and use intravascular imaging guidance when appropriate to aim at minimizing acute ISA. In addition, the active search for new stent platforms that could accommodate vessel remodeling over time (i.e., self-expandable stents) and for new polymers and/or eluting drugs that could induce less inflammation (hence, less positive remodeling) could ultimately reduce the occurrence of ISA and its potentially harmful consequences.

Meta-analysis of bioabsorbable versus durable polymer drug-eluting stents in 20,005 patients with coronary artery disease: an update

OBJECTIVES

To perform an updated meta-analysis comparing biodegradable polymer drug eluting stents (BP-DES) and durable polymer drug eluting stents (DP-DES).

BACKGROUND

BP-DES have been suggested to reduce late stent thrombosis (LST) rates as compared to first generation DP-DES. Recently, second generation DP-DES have replaced older DES, but comparison of these stents with BP-DES has not yielded consistent results.

METHODS

Medline/Web databases were searched for studies comparing BP-DES and DP-DES, and reporting rates of overall/cardiac mortality, myocardial infarction (MI), LST, target lesion revascularization (TLR) and target vessel revascularization (TVR) and late lumen loss (LLL), with a follow-up ≥6 months.

RESULTS

Twenty studies (20,005 patients) were included in the meta-analysis. Median follow-up time was 1 year. Compared with DP-DES, BP-DES showed lower LLL (in stent: weighted mean difference WMD -0.45 mm, 95% CI -0.66 to -0.24 mm, P = 0.00001; in segment: WMD -0.15 mm, 95% CI = -0.24 to -0.06 mm, P = 0.001) and lower rates of LST (OR 0.51, 95% CI = 0.30 to 0.86, P = 0.01), although they did not improve mortality, MI, TLR, and TVR rates. BP-DES coated with sirolimus or novolimus, in comparison with biolimus or paclitaxel, were associated with reduced LLL (P < 0.0001 for subgroups).

CONCLUSIONS

In comparison with DP-DES, BP-DES significantly reduce LLL and LST rates, without clear benefits on harder endpoints. The efficacy of BP-DES in preserving lumen patency seems larger for sirolimus and novolimus DES.

Difference of vascular response between everolimus- and paclitaxel-eluting stents for small coronary artery disease: Optical coherence tomography analysis

Background

Previous clinical trials have demonstrated the clinical and angiographic superiority of everolimus-eluting stents (EES) compared with paclitaxel-eluting stents (PES) in the small coronary vessel. However, the differences of vascular response including assessment of morphological neointimal tissue (NIT) characteristics using optical coherence tomography (OCT) have not been fully evaluated. The aim of this study is to evaluate the differences of chronic vascular response following small coronary stenting between EES and PES using OCT.

Methods and results

A prospective OCT examination at 9 month follow-up was performed for 50 small coronary artery diseases (50 patients) treated by a single 2.5 mm stent for each stent group. Cross-sectional area within stent segments were analyzed at an interval of 1 mm. NIT structure (homogeneous or heterogeneous) was evaluated for qualitative assessment. Homogeneous NIT was observed significantly higher and heterogeneous NIT was lower in EES compared with PES (93% vs. 89%; p = 0.003, 6.5% vs. 10.3%; p = 0.002, respectively). The frequencies of exposed and malapposed struts were lower in EES compared with PES (0.2% vs. 1.7%; p = 0.0001, 0.1% vs. 0.3%; p = 0.001, respectively). NIT eccentricity index and NIT area were lower in EES compared with PES (0.69 ± 0.08 vs. 0.76 ± 0.10; p = 0.001, 0.97 ± 0.42 mm² vs. 1.27 ± 0.67 mm²; p = 0.01, respectively).

Conclusions

A favorable vascular response was observed after EES implantation compared with PES for small coronary artery disease. In addition, the characteristics of NIT after EES implantation were more stable than PES at 9 month follow-up.

Incidences, Predictors, and Clinical Outcomes of Acute and Late Stent Malapposition Detected by Optical Coherence Tomography After Drug-Eluting Stent Implantation

Background—

We investigated the incidences, predictors, and clinical outcomes of acute and late stent malapposition detected by optical coherence tomography (OCT) after drug-eluting stent implantation.

Methods and Results—

We analyzed the OCT images from 351 patients with 356 lesions who received poststent and follow-up OCT examinations. Acute stent malapposition was observed in 62% of lesions. Approximately half of the acute stent malappositions were located within the edges of the stents. Severe diameter stenosis, calcified lesions, and long stents were independent predictors of acute stent malapposition. Follow-up OCT examinations were performed 175±60 days after drug-eluting stent implantation. Thirty-one percent of lesions with acute stent malapposition remained malapposed (late-persistent stent malapposition) and were typically (72%) located within the edges of the stent. The location within the stent edges and the volume of acute stent malapposition were independent predictors of late-persistent stent malapposition. Acute stent malapposition with a volume >2.56 mm 3 differentiated late-persistent stent malapposition from resolved acute stent malapposition. Late-acquired stent malapposition was detected in 15% of all lesions and was usually (61%) located within the stent body. Late-acquired stent malapposition was more frequently associated with plaque/thrombus prolapse on poststent OCT images (70% versus 42%; P <0.001). Clinical events, including cardiovascular death, nonfatal myocardial infarction, and stent thrombosis, did not occur in patients with late stent malapposition during the follow-up period of 28.6±10.3 months after drug-eluting stent implantation.

Conclusions—

Acute, late-persistent, and late-acquired stent malapposition had relatively high incidences but different predictors. The clinical outcome of stent malapposition was favorable.