Late stent malapposition risk is higher after drug-eluting stent compared with bare-metal stent implantation and associates with late stent thrombosis

IVUS Findings in Late and Very Late Stent Thrombosis. A Comparison Between Bare-metal and Drug-eluting Stents

INTRODUCTION AND OBJECTIVES

Stent thrombosis (ST) is a life-threatening complication after stent implantation. Intravascular ultrasound is able to discern most causes of ST. The aim of this study was to compare intravascular ultrasound findings between bare-metal stents (BMS) and drug-eluting stents (DES) in patients with late (31 days to 1 year) or very late ST (> 1 year).

METHODS

Of 250 consecutive patients with late or very late ST in 7 Spanish institutions, 114 patients (45.5% BMS and 54.5% DES) were imaged with intravascular ultrasound. Off-line intravascular ultrasound analysis was performed to assess malapposition, underexpansion, and neoatherosclerosis.

RESULTS

The median time from stent implantation to ST was 4.0 years with BMS and 3.4 years with DES (P = .04). Isolated malapposition was similarly observed in both groups (36.5% vs 46.8%; P = .18) but was numerically lower with BMS (26.6% vs 48.0%; P = .07) in patients with very late ST. Isolated underexpansion was similarly observed in both groups (13.5% vs 11.3%; P = .47). Isolated neoatherosclerosis occurred only in patients with very late ST and was more prevalent with BMS (22.9%) than with DES (6.0%); P = .02. At 2.9 years' follow-up, there were 0% and 6.9% cardiac deaths, respectively (P = .06) and recurrent ST occurred in 4.0% and 5.2% of patients, respectively (P = .60).

CONCLUSIONS

Malapposition was the most common finding in patients with late and very late ST and is more prevalent with DES in very late ST. In contrast, neoatherosclerosis was exclusively observed in patients with very late ST and mainly with BMS.

Angiographic and clinical performance of polymer-free biolimus-eluting stent in patients with ST-segment elevation acute myocardial infarction in a metropolitan public hospital: The BESAMI MUCHO study

OBJECTIVES

This study aimed at assessing the performance of a new generation polymer-free biolimus-eluting stent (BES) in real-world patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Polymers components of early-generation drug-eluting stents have been implicated in the pathogenesis of delayed arterial healing, vessel remodeling, and delayed stent thrombosis. Recently, a novel polymer-free BES has shown excellent clinical performance in clinical trial setting.

METHODS

Overall, 175 consecutive patients (64 ± 14 years, 141 men) treated with the BioFreedom (Biosensors Europe, Morges, Switzerland) polymer-free BES because of STEMI were included in this study. The primary endpoint was the rate of major adverse cardiac events (MACE), a composite of cardiac death, recurrent myocardial infarction, and ischemia-driven target vessel revascularization at 1 year follow-up. A subgroup of patients underwent 6-month angiographic follow-up. Dual antiplatelet therapy was prescribed for 12 months after STEMI.

RESULTS

At 1 year, the cumulative rate of MACE was 4.6%. One patient (0.6%) had an arrhythmic cardiac death and five (2.9%) had ischemia-driven target vessel revascularization, although only three (1.7%) had target lesion revascularization. Two (1.1%) patients had acute stent thrombosis yielding nonfatal myocardial infarction. In 70 patients (63 ± 14 years, 61 men), quantitative coronary angiography at 6-month follow-up revealed diameter stenosis of 24.1 ± 13.7% and minimal lumen diameter of 2.29 ± 0.56 mm, yielding a late lumen loss of 0.13 ± 0.14 mm.

CONCLUSIONS

In real-world setting, implantation of a new-generation polymer-free BES during STEMI is associated with favorable clinical and angiographic results, pointing toward the overall efficacy and safety of the device in complex clinical scenarios.

The fate of incomplete scaffold apposition of everolimus-eluting bioresorble scaffolds: A serial optical coherence tomography analysis

BACKGROUND

Incomplete stent apposition (ISA) can be divided into acute and late forms. Late ISA may be due to persistent ISA or late-acquired ISA (LAISA). This study evaluated the natural course of ISA after bioresorbable vascular scaffold (BRS) implantation using optical coherence tomography (OCT).

METHODS

Thirty-two patients (45 BRS) were assessed immediately after BRS implantation and 1 year thereafter using OCT. Acute ISA identified after BRS implantation but absent at follow-up was defined as resolved; otherwise, it was considered persistent. LAISA was defined as newly developed ISA that was identified at follow-up despite complete apposition immediately after BRS implantation. Intra-BRS fibrin-like material (IBF) was identified as an irregular intraluminal mass. ISA percentage was expressed as follows: (number of ISA/total number of BRS struts)×100.

RESULTS

Among 45 BRS and 15,894 analyzed BRS struts, 34 and 882 had acute ISA post-procedure, respectively. At follow-up, 92 of 15,364 analyzed struts exhibited late ISA (64 persistent ISA and 28 LAISA). In 15 of 28 struts with LAISA, LAISA occurred at the sites adjacent to post-interventional dissection. Uncovered struts were more frequently observed in late ISA compared to apposed struts (3.7±4.8 vs. 0.58±2.2%, p=0.09). IBF was significantly more common in BRS with late ISA (62.5 vs. 8.1%, p=0.02). Receiver-operating characteristic curve analysis identified a cut-off value of 280μm for acute ISA distance predicting persistent ISA.

CONCLUSION

Resolution of acute ISA after BRS is common. The occurrence of LAISA may be infrequent and may be a nidus of stent thrombosis.

Neointimal Healing Evaluated by Optical Coherence Tomography after Drug-Eluting Absorbable Metal Scaffold Implantation in de novo Native Coronary Lesions: Rationale and Design of the Magmaris-OCT Study

Objectives: We sought to explore neointimal healing assessed by optical coherence tomography (OCT) following implantation of the Magmaris sirolimus-eluting absorbable metal scaffold. Methods: The Magmaris-OCT is a prospective, multicenter, single-arm observational clinical study, intended to enrol 60 consecutive patients with up to 2 de novo native coronary lesions, each located in different major epicardial vessels, with a reference vessel diameter of 2.5-3.5 mm, and a maximum lesion length of 20 mm. Patients will undergo Magmaris scaffold implantation in the target lesion, according to the standard practice. Clinical follow-up will take place at 30 days, and at 3, 6, 9, and 12 months. For invasive-imaging follow-up, patients will be classified into 3 groups: cohort A will be scheduled for follow-up at 3 months, cohort B at 6 months, and cohort C at 12 months. Invasive imaging will include quantitative coronary angiography, OCT evaluation, and coronary flow reserve measurement. The primary end point will be the percentage of uncovered scaffold struts assessed by OCT at the prespecified follow-up. Conclusions: This study will provide insight into the short- and mid-term healing properties following Magmaris scaffold implantation, with special emphasis on the neointimal coverage of scaffold struts.

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.

Impact of branching angle on neointimal coverage of drug-eluting stents implanted in bifurcation lesions

OBJECTIVES

To investigate the impact of branching angle (BA) on neointimal coverage of drug-eluting stents (DESs) in bifurcation lesions.

BACKGROUND

Previous experimental studies indicated that BA influences the local flow turbulence and wall shear stress, which are associated with neointimal coverage of DESs.

METHODS

Fifty-five bifurcation lesions in 47 patients were evaluated by serial optical coherence tomography (OCT) before DES implantation and at follow-up. Neointimal coverage was assessed in cross-sectional OCT images containing the side branch; regions including the side branch ostium (SO) and vessel wall (VW) were assessed separately. BA was measured using angiography (Angio-BA) and longitudinal OCT imaging (OCT-BA).

RESULTS

In the SO region, a significant negative correlation was found between the uncovered strut percentage and Angio-BA or OCT-BA (r=-0.41, P=0.0024; r=-0.33, P=0.0167, respectively) and a significant positive correlation was found between Angio-BA and average neointimal thickness (r=0.31, P=0.025), whereas no correlation was observed between OCT-BA and average neointimal thickness (r=0.20, P=0.158). In the VW region, no correlation was found between Angio-BA or OCT-BA and the uncovered strut percentage or average neointimal thickness.

CONCLUSION

BA influence the neointimal coverage over DES struts in the SO at coronary bifurcation lesions, but not in those attached to the VW.

Immediate and short-term performance of a novel sirolimus-coated balloon during complex percutaneous coronary interventions. The FAtebenefratelli SIrolimus COated-balloon (FASICO) registry

BACKGROUND AND PURPOSES

Drug-coated balloons (DCB) currently represent an alternative to drug-eluting stents (DES) for the treatment of in-stent restenosis and they are also variably used for small coronary vessel and bifurcation lesion management. All DCB variably elute paclitaxel as an anti-proliferative drug. The first sirolimus coated balloon (SCB) received the CE mark in 2016, but its clinical performance has not been shown yet.

METHODS AND RESULTS

FASICO in an all-comer registry of the first consecutive patients with at least one lesion treated with SCB between March and July 2016 at the first European centre that used this device. All patients were prospectively enrolled in a dedicated database. Primary endpoint was procedural success; co-primary endpoint was the rate of major adverse cardiac events at short-term follow-up. The 32 patients (34 lesions) enrolled had at least 6-month clinical follow up available. Forty-five percent had diabetes and indication to PCI was ISR in 47% of the cases. Lesions were always pre-dilated and device deployment was successful in all the cases. Procedural success was achieved in 100% of patients. We observed 3 cases of TLR at follow-up.

CONCLUSIONS

SCB shows high immediate technical performance and adequate short-term efficacy and safety. The ongoing EASTBOURNE registry will shed light on mid-and long-term performance of this device in an adequately powered population.

Clinical, humanistic, and economic outcomes between drug-eluting stent (DES) and bare metal stent (BMS): 18-month follow-up study

BACKGROUND

Percutaneous coronary intervention (PCI) is one of the most performed interventions for ischemic heart diseases. In Hong Kong, the total number of patient discharges and deaths for ischemic heart diseases in 2009 was 33,363, including 4,360 deaths. There are over 5,000 cases of PCI yearly. This study aimed to compare clinical, economic, and humanistic outcomes among patients receiving drug-eluting stent (DES) or bare metal stent (BMS) in Hong Kong.

METHODS

Patients who received stent implantation between September 15, 2009 and October 11, 2010 in Prince of Wales Hospital, Hong Kong, were recruited and followed for 18 months. Occurrence of major adverse cardiac events (cardiac death, non-fatal MI, TLR and TVR) was employed as the clinical outcome measurements. Improvement in quality-of-life by stent interventions was measured as quality-adjusted life-year (QALY). EQ-5D questionnaire was adopted to assess the QALY gained. Cost-utility analysis and cost-effectiveness analysis for BMS and DES were employed as the economic outcome measurement.

RESULTS

Six hundred and eighty-four patients (DES = 402; BMS = 282) were included. From 0-18 months, TLR rate (2.7% vs 3.5%, p = .549) and TVR rate (3.7% vs 6.4%, p = .111) were lower in the DES group, but without statistical significance. EQ VAS (71.06 ± 14.56 vs 71.07 ± 16.57, p = .998) and utility score (0.81 ± 0.17 vs 0.78 ± 0.16, p = .162) were comparable between DES and BMS group. Overall, the cost per QALY gained was HKD + 1,178,100 and ICER was HKD + 187,000 (1USD = 7.8 HKD).

CONCLUSIONS

No significant difference in TVR, TLR rates, EQ VAS, and utility score was found between the DES and BMS group. The higher cost of index procedure for the DES group was found to be partly offset by reduced cost of follow-up, offering cost-effectiveness in ACS patients, predominantly in STEMI patients. DES was recommended for STEMI patients.

Usefulness of Post-coronary Dilation to Prevent Recurrent Myocardial Infarction in Patients Treated With Percutaneous Coronary Intervention for Acute Coronary Syndrome (from the BASE ACS Trial)

Stent underexpansion is associated with worse outcome after stent implantation. Whether post-dilation (PD) improves outcome in patients with acute coronary syndrome (ACS) remains unclear. We performed post hoc analysis of outcome in patients from the BASE ACS (A prospective randomized comparison of titanium-nitride-oxide-coated bioactive stents with everolimus-eluting stents in acute coronary syndrome) trial who underwent PD versus those who did not. The BASE ACS trial randomized 827 patients (1:1) with ACS to receive either titanium-nitride-oxide-coated bioactive stents or everolimus-eluting stents. The primary end point was major adverse cardiac events (MACE): a composite of cardiac death, nonfatal myocardial infarction (MI), or ischemia-driven target lesion revascularization. Follow-up was planned at 12 months and yearly thereafter for up to 7 years. Of 827 patients enrolled in the BASE ACS trial, 357 (43.2%) underwent PD. Median follow-up duration was 5 years. Patients who underwent PD had less frequent nonfatal MI events at long-term follow-up, compared with those who did not (4.5% vs 8.5%, respectively, p = 0.02). The rates of MACE (15.7% vs 15.1%, respectively, p = 0.81), and the other endpoints, were not significantly different (p >0.5 for all). The results were consistent in propensity score-matched analysis (270 pairs). In patients treated with bioactive stents, those who underwent PD had a trend for a fewer nonfatal MI events (p = 0.076). Comparably, in patients treated with everolimus-eluting stents, MACE and all the individual end points were comparable (p >0.5 for all). In conclusion, patients treated with early percutaneous coronary intervention for ACS who underwent PD had less frequent nonfatal MI events at long-term follow-up, compared with those who did not; MACE rates were not significantly different.

Automated detection of vessel lumen and stent struts in intravascular optical coherence tomography to evaluate stent apposition and neointimal coverage

PURPOSE

Intravascular optical coherence tomography (IV-OCT) is a high-resolution imaging method used to visualize the microstructure of arterial walls in vivo. IV-OCT enables the clinician to clearly observe and accurately measure stent apposition and neointimal coverage of coronary stents, which are associated with side effects such as in-stent thrombosis. In this study, the authors present an algorithm for quantifying stent apposition and neointimal coverage by automatically detecting lumen contours and stent struts in IV-OCT images.

METHODS

The algorithm utilizes OCT intensity images and their first and second gradient images along the axial direction to detect lumen contours and stent strut candidates. These stent strut candidates are classified into true and false stent struts based on their features, using an artificial neural network with one hidden layer and ten nodes. After segmentation, either the protrusion distance (PD) or neointimal thickness (NT) for each strut is measured automatically. In randomly selected image sets covering a large variety of clinical scenarios, the results of the algorithm were compared to those of manual segmentation by IV-OCT readers.

RESULTS

Stent strut detection showed a 96.5% positive predictive value and a 92.9% true positive rate. In addition, case-by-case validation also showed comparable accuracy for most cases. High correlation coefficients (R > 0.99) were observed for PD and NT between the algorithmic and the manual results, showing little bias (0.20 and 0.46 μm, respectively) and a narrow range of limits of agreement (36 and 54 μm, respectively). In addition, the algorithm worked well in various clinical scenarios and even in cases with a low level of stent malapposition and neointimal coverage.

CONCLUSIONS

The presented automatic algorithm enables robust and fast detection of lumen contours and stent struts and provides quantitative measurements of PD and NT. In addition, the algorithm was validated using various clinical cases to demonstrate its reliability. Therefore, this technique can be effectively utilized for clinical trials on stent-related side effects, including in-stent thrombosis and in-stent restenosis.

Late-acquired incomplete stent apposition after everolimus-eluting stent versus sirolimus-eluting stent implantation in patients with non-ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction

AIMS

Our aim was to evaluate the incidence and clinical outcomes of late-acquired incomplete stent apposition (LAISA) after implantation of first- and second-generation drug-eluting stents in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

Late-Acquired incomplete stent aPPOsition after everolimus-eluting stent versus sirolimus-eluting Stent ImplanTatION in pAtients with non ST-segment elevation Myocardial Infarction and ST-segment elevation myocardial infarction (APPOSITION-AMI) was a prospective, randomised study comparing LAISA after everolimus-eluting stent (EES) and sirolimus-eluting stent (SES) implantation in AMI patients. Intravascular ultrasound examination was serially performed post-procedurally and at eight-month follow-up in 195 AMI patients (205 native coronary lesions: 100 EES; 105 SES). LAISA was observed in 6.0% and 16.2% of EES- vs. SES-treated lesions (p=0.021), respectively. In 64.7% of SES-treated lesions, LAISA was caused by positive remodelling, whereas thrombus dissolution or plaque reduction was observed in 66.7% of EES-treated lesions. Among patients with LAISA, MACE developed in one (4.5%) in the SES group with no ST in either group up to one year.

CONCLUSIONS

The incidence of LAISA was lower in AMI patients treated with EES as compared to SES, mainly secondary to positive remodelling in SES- but not EES-treated lesions. Patients with LAISA in both groups showed a very low MACE incidence at one-year follow-up.

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.

Drug-Eluting Balloons in the Treatment of Coronary De Novo Lesions: A Comprehensive Review

Drug-eluting balloons (DEBs) have emerged as a new application in percutaneous coronary intervention. DEBs have proven successful in the treatment of in-stent restenosis, but their role in de novo lesions is less clear. This paper provides a review of the current studies where DEBs have been used in coronary de novo lesions, either as part of a DEB-only strategy or in combination with another device, mainly a bare metal stent (BMS). By searching Pubmed and Embase we were able to identify 52 relevant studies, differing in design, intervention, and clinical setting, including patients with small vessel disease, bifurcation lesions, complex long lesions, acute myocardial infarction, diabetes mellitus, and elderly. In 23 studies, a DEB was combined with a BMS, 25 studies used a DEB-only strategy with only provisional BMS implantation, and four studies combined a DEB with a drug-eluting stent (DES). In the vast majority of studies, DEB in combination with BMS does not seem to improve clinical or angiographic outcome compared with DES, whereas a DEB-only strategy seems promising, especially when predilatation and geographical mismatch are taken into account. A lower risk of recurrent thrombosis with DEB compared with DES is not evident from the current studies. In conclusion, the main indication for DEB seems to be small vessel disease, especially in clinical scenarios in which a contraindication to dual antiplatelet therapy exists. The main approach should be a DEB-only strategy with only provisional bailout stenting, which has shown interesting results in different clinical scenarios. In general, larger randomized controlled studies with prolonged follow-up comparing DEB with best in class DES are warranted. Technical developments of DEBs including the use of different drugs might potentially improve the efficacy of such treatment.

Dextran or Saline Can Replace Contrast for Intravascular Optical Coherence Tomography in Lower Extremity Arteries

PURPOSE

To examine the hypothesis that alternative flush media could be used for lower extremity optical coherence tomography (OCT) imaging in long lesions that would normally require excessive use of contrast.

METHODS

The OPTical Imaging Measurement of Intravascular Solution Efficacy (OPTIMISE) trial was a single-center, prospective study (ClinicalTrials.gov identifier NCT01743872) that enrolled 23 patients (mean age 68±11 years; 14 men) undergoing endovascular intervention involving the superficial femoral artery. Four flush media (heparinized saline, dextran, carbon dioxide, and contrast) were used in succession in random order for each image pullback. Quality was defined as ≥270° visualization of vessel wall layers from each axial image. Mean proportions (± standard deviation) of image quality for each flush medium were assessed using 1-way analysis of variance and are reported with the 95% confidence intervals (CI).

RESULTS

Four OCT catheters failed, leaving 19 patients who completed the OCT imaging protocol; from this cohort, 51 highest quality runs were selected for analysis. Average vessel diameter was 3.99±1.01 mm. OCT imaging allowed 10- to 15-μm resolution of the lumen border, with diminishing quality as vessel diameter increased. Plaque characterization revealed fibrotic lesions. Mean proportions of image quality were dextran 87.2%±12% (95% CI 0.81 to 0.94), heparinized saline 74.3%±24.8% (95% CI 0.66 to 0.93), contrast 70.1%±30.5% (95% CI 0.52 to 0.88), and carbon dioxide 10.0%±10.4% (95% CI 0.00 to 0.26). Dextran, saline, and contrast provided better quality than carbon dioxide (p<0.001).

CONCLUSION

OCT is feasible in peripheral vessels <5 mm in diameter. Dextran or saline flush media can allow lesion characterization, avoiding iodinated contrast. Carbon dioxide is inadequate for peripheral OCT imaging. Axial imaging may aid in enhancing durability of peripheral endovascular interventions.

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.

One-Year Results of Bioresorbable Vascular Scaffolds for Coronary Chronic Total Occlusions

The potential of bioresorbable vascular scaffold (BVS) technology has been demonstrated in first-in-man studies with up to 5-year follow-up. This study sought to investigate the 1-year outcomes of the BVS, for the treatment of chronic total occlusions (CTOs), using various imaging techniques. Thirty-five true CTO lesions treated with BVS were included in this prospective study. Scaffolds were deployed after mandatory predilation and intravascular ultrasound analysis. Optical coherence tomography was performed after BVS implantation and at 10 to 12 months. Multislice computed tomography was performed at baseline and at 6 to 8 months. Mean patient age was 61 ± 10 years. The most frequent vessel treated was the right coronary artery (46%). Lesions were classified as intermediate (49%) or difficult/very difficult (26%) according to the Japanese CTO complexity score. Predilation was performed in 100% of lesions, using cutting balloons in 71% of these. The total scaffold length implanted per lesion was of 52 ± 23 mm. All scaffolds were delivered and deployed successfully. Postdilation was undertaken in 63%. By multislice computed tomography at 6 months, we observed 2 cases of asymptomatic scaffold restenosis, subsequently confirmed by angiography. At 12 months, no scaffold thrombosis or major adverse cardiac events were reported. The optical coherence tomography at follow-up showed that 94% of struts were well apposed and covered (5% of uncovered struts and 1% of nonapposed struts), and only 0.6% of struts were nonapposed and uncovered. In conclusion, 1-year results suggest that BVS for CTO is associated with excellent clinical and imaging outcomes. Accurate percutaneous coronary BVS technique might have enabled these promising results.

The effects of plasma electrolytically oxidized NiTi on in vitro endothelialization

The role of biomaterials surface in controlling the interfacial biological events leading to implant integration is of key importance. In this study, the effects of NiTi surfaces treated by plasma electrolytic oxidation (PEO) on human umbilical vein endothelial cells (HUVECs) have been investigated. The changes in NiTi surface morphology and chemistry were assessed by SEM, XPS and cross-section TEM/EDX analyzes whereas the effects of the resultant surfaces on in vitro endothelialization and cell junction proteins have been evaluated by life/dead staining, SEM, cells counting, qPCR and immunofluorescence. The findings indicated that the PEO-treated NiTi, with a microporous morphology and oxide dominated surface chemistry, supports viability and proliferation of HUVECs. Numerous thin filopodia probing the microporous surface assisted cells attachment. In addition, claudin-5 and occludin have been upregulated and expression of vascular endothelial-cadherin was not suppressed on PEO-treated NiTi relative to the reference electropolished surfaces. The results of this study suggest that novel NiTi surfaces may be developed using the PEO process, which can be of benefit to atherosclerosis treatment.

Impact of intravascular ultrasound on the long-term clinical outcomes in the treatment of coronary ostial lesions

OBJECTIVES

To evaluate the long-term outcomes of patients with ostial lesions who underwent percutaneous coronary intervention (PCI) with and without the use of intravascular ultrasound (IVUS).

BACKGROUND

A higher rate of adverse cardiac events is associated with PCI of ostial lesions as compared with nonostial disease.

METHODS

From 7/2002 to 8/2010, 225 patients with 233 coronary ostial lesions underwent PCI with (n = 82) and without (n = 143) IVUS guidance. Ostial lesions included both native aorto-ostial or major coronary vessel (left anterior descending, left circumflex, and ramus intermedius) lesions. Clinical outcomes [cardiovascular death, myocardial infarction (MI), and target lesion revascularization (TLR)] at a mean follow-up of 4.2 ± 2.5 years were compared between patients undergoing PCI of an ostial lesion with and without use of IVUS using univariate and propensity score adjusted analyses.

RESULTS

Aorto-ostial lesions (n = 109) comprised 47% of lesions, whereas the remaining lesions (53%) involved major coronary vessels. After propensity score adjustment, IVUS use was associated with lower rates of the composite of cardiovascular death, MI, or TLR (HR 0.54, 95% CI 0.29-0.99; P = 0.04), composite MI or TLR (HR 0.39, 95% CI 0.18-0.83; P = 0.01), and MI (HR 0.31, 95% CI 0.11-0.85; P = 0.02) as compared with no IVUS. The use of IVUS was also associated with a trend towards a lower rate of TLR (HR 0.42, 95% CI 0.17-1.02; P = 0.06).

CONCLUSIONS

PCI of coronary ostial lesions with the use of IVUS was associated with significantly lower rates of adverse cardiac events.

Coronary evaginations and peri-scaffold aneurysms following implantation of bioresorbable scaffolds: incidence, outcome, and optical coherence tomography analysis of possible mechanisms

BACKGROUND

Peri-stent coronary evaginations may disturb flow and have been proposed as possible risk factor for late stent thrombosis. We describe incidence, predictors, and possible mechanisms of coronary evaginations 12 months after implantation of bioresorbable vascular scaffolds (BVS).

METHODS AND RESULTS

One hundred and two BVS implanted in 90 patients (age 63 ± 13 years, 71 males, 14 diabetics) were analysed with angiography and optical coherence tomography (OCT) 12 months after implantation. Evaginations were identified as any hollow in the luminal vessel contour between well-apposed struts and were classified as major when extending ≥3 mm with a depth ≥10% of the BVS diameter. Fifty-five (54%) of the BVS (50(56%) of the patients) had at least one evagination (6.1 ± 6.2 evaginations per BVS), with a mean volume of 1.9 ± 1.9 mm(3). Major evaginations were only found in one patient, and in-BVS aneurysms in three patients (4BVS). The presence of evaginations was strongly associated with that of malapposition (P = 0.003) and strut fractures (P = 0.01). No association could be shown between the presence and volume of the evaginations and any clinical variable or the presence of uncovered struts (P > 0.5). Peri-strut low-intensity areas (PSLIA) were present in 29 (53%) of the BVS with evaginations and 12 (26%) of those without (P = 0.0049); their presence was independently associated with the presence, the number (P < 0.003) and volume of the evaginations (P = 0.004) and with that of strut fracture.

CONCLUSIONS

Optical coherence tomography-detected evaginations are relatively common after BVS implantation, but, as for modern drug-eluting metallic stents, major evaginations are very rare. Optical coherence tomography evidence of immature neointima and strut fractures were associated with more severe development of evaginations.

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.

Optical coherence tomography analysis of the stent strut and prediction of resolved strut malapposition at 3 months after 2nd-generation drug-eluting stent implantation

Our objective was to clarify whether thrombogenic problems with stent struts are resolved at 3 months after 2nd-generation drug-eluting stent implantation. Twenty-one patients with stable angina pectoris having 28 (22 zotarolimus-eluting, 6 everolimus-eluting) stents with optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) were evaluated. Stent strut coverage and malapposition were evaluated by OCT immediately after PCI and at 3-month follow-up. Acute strut malapposition was observed in 26 out of 28 analyzed stents (92.9 %). At 3-month follow-up, 7 (26.9 %) of those 26 stents with strut malapposition were completely resolved, and the mean percentages of uncovered struts and malapposed struts were 8.3 and 2.0 % when analyzed by each individual stent. When analyzing a total of 30,060 struts, 807 struts (2.7 %) demonstrated acute strut malapposition. Among these, 219 struts (27.1 %) demonstrated persistent strut malapposition. On the basis of receiver-operating characteristic curve analysis, a strut-to-vessel (S-V) distance ≤160 µm on post-stenting OCT images was the corresponding cutoff point for resolved malapposed struts (sensitivity 78.1 %, specificity 62.8 %, area under the curve 0.758). The S-V distance of persistent malapposed struts on post-stenting OCT images was longer than that of resolved malapposed struts (235 ± 112 vs. 176 ± 93 µm, p < 0.01). At 3 months after PCI, the prevalence rates of uncovered and malapposed struts were relatively low in 2nd-generation drug-eluting stent. Our results suggest that OCT-guide PCI with an S-V distance ≤160 µm may be recommended especially in patients with planed short-term DAPT.

Compensatory Enlargement of Ossabaw Miniature Swine Coronary Arteries in Diffuse Atherosclerosis

Studies in human and non-human primates have confirmed the compensatory enlargement or positive remodeling (Glagov phenomenon) of coronary vessels in the presence of focal stenosis. To our knowledge, this is the first study to document arterial enlargement in a metabolic syndrome animal model with diffuse coronary artery disease (DCAD) in the absence of severe focal stenosis. Two different groups of Ossabaw miniature pigs were fed a high fat atherogenic diet for 4 months (Group I) and 12 months (Group II), respectively. Group I (6 pigs) underwent contrast enhanced computed tomographic angiography (CCTA) and intravascular ultrasound (IVUS) at baseline and after 4 months of high fat diet, whereas Group II (7 pigs) underwent only IVUS at 12 months of high fat diet. IVUS measurements of the left anterior descending (LAD), left circumflex (LCX) and right coronary (RCA) arteries in Group I showed an average increase in their lumen cross-sectional areas (CSA) of 25.8%, 11.4%, and 43.4%, respectively, as compared to baseline. The lumen CSA values of LAD in Group II were found to be between the baseline and 4 month values in Group I. IVUS and CCTA measurements showed a similar trend and positive correlation. Fractional flow reserve (FFR) was 0.91 ± 0.07 at baseline and 0.93 ± 0.05 at 4 months with only 2.2%, 1.6% and 1% stenosis in the LAD, LCX and RCA, respectively. The relation between percent stenosis and lumen CSA shows a classical Glagov phenomenon in this animal model of DCAD.

Stent boost subtract imaging for the assessment of optimal stent deployment in coronary ostial lesion intervention: comparison with intravascular ultrasound

Percutaneous coronary intervention (PCI) of ostial lesions is complex and is technically very demanding. Intravascular ultrasound (IVUS) is considered the gold standard method to guide PCI but has several limitations. Stent boost subtract (SBS) imaging is an enhancement of the radiologic edge of the stent by digital management of regular X-ray images. The purpose of this study was to determine the availability of stent enhancement with SBS during ostial PCI by comparison with IVUS.We investigated SBS and IVUS after stent implantation in 58 ostial lesions in 55 patients. SBS and IVUS were performed in all patients to obtain improved stent location and to detect optimal release and deployment. We defined the SBS and IVUS criteria for accuracy of stent location and adequate stent deployment. IVUS findings showed that stent location was generally good. The location was accurate in 48 (82.8%) and inadequate stent deployment was observed in 10 of 58 (17.2%). Eight SBS images showed inadequate stent expansion. SBS predicted inadequate findings of IVUS with 100% specificity and 80% sensitivity, while a significant positive correlation was observed between SBS-MSA and MSA by IVUS with a regression coefficient of 0.95.Imaging techniques have a primary role during ostial PCI. SBS is a simple and quick method that offers several advantages, enabling improved stent location, adequate stent expansion, and optimal apposition of the struts to the wall. SBS imaging could be conventionally used during ostial PCI, especially in centers where IVUS is not used routinely.

Stent thrombosis in early-generation drug-eluting stents versus newer-generation everolimus-eluting stent assorted by LVEF

OBJECTIVE

Everolimus drug-eluting stents (EES) are superior to early-generation drug-eluting stents (DES), releasing sirolimus (SES) or paclitaxel (PES) in preventing stent thrombosis (ST). Since an impaired LVEF seems to increase the risk of ST, we aimed to investigate the difference in outcome of patients with varying LVEF using EES versus early-generation DES.

METHODS

In a prospective cohort study, we compared the risk of ST in patients in three LVEF subgroups: normal (LVEF >50%), mildly impaired (LVEF >40% and ≤50%) and moderate-severely impaired (LVEF ≤40%). Within these various LVEF groups, we compared EES with SES and PES after adjustment for baseline differences.

RESULTS

We assessed a cohort of 5363 patients, with follow-up of up to 4 years and available LVEF. Overall definite ST occurred in 123 (2.3%) patients. ST rates were higher in the LVEF moderate-severely impaired group compared with the normal LVEF group (2.8% vs 2.1%; HR 1.82; CI 1.10 to 3.00). Especially early ST (EST) was more frequent in the moderate-severely impaired LVEF group (HR 2.20; CI 1.06 to 4.53). Overall rates of definite ST were lower in patients using EES compared with patients using SES or PES in all LVEF groups. Interaction terms were not statistically significant. ST rates were higher in the moderate-severely impaired LVEF group compared with the normal LVEF group when using SES or PES, but not significantly different when using EES.

CONCLUSIONS

EES was associated with a lower risk of definite ST compared with early-generation DES. This lower risk was independent of LVEF, even though ST rates were higher in patients with a moderate-severely impaired LVEF.

TRIAL REGISTRATION NO

MEC-2013-262.

Simultaneous occlusion of left anterior descending and left circumflex arteries by very late stent thrombosis: vascular response to drug-eluting stents assessed by intravascular ultrasound

Very late stent thrombosis (VLST) is a catastrophic complication after implantation of a drug-eluting stent (DES). It has been reported that VLST is associated with pathological changes, which often include late acquired incomplete stent apposition (LAISA) with thrombus formation. In addition, the vascular response to the stent (evaginations, neointimal growth, and thrombosis) and the incidence of LAISA are reported to vary among the different types of DES. We experienced a patient with cardiogenic shock induced by simultaneous VLST of both the left anterior descending artery (LAD) and the left circumflex artery (LCX) at 3 years after implantation of two sirolimus-eluting stents. Intravascular ultrasound (IVUS) showed LAISA of both arteries. A paclitaxel-eluting stent, which had been implanted in the right coronary artery 3 years earlier, did not show such a finding. IVUS revealed "different vascular reactions" to "different types of DES" in this patient.

Optical coherence tomography-guided treatment of very late stent thrombosis caused by inaccurate stent deployment in a bifurcation

: A 65-year-old man presented at our institution with anterior wall reinfarction, due to very late stent thrombosis, 4 years after primary angioplasty on the first bifurcation of the left anterior descending artery. Using intravascular optical coherence tomography, we identified stent malapposition in the proximal left anterior descending artery, occurring during the first primary angioplasty, as the probable cause of the very late stent thrombosis. Imaging with optical coherence tomography guided our treatment strategy of mechanical and pharmacological thrombectomy, followed by staged stent postdilatation.

Peri-stent contrast staining, major evaginations and severe malapposition after biolimus-eluting stent implantation: a case report based on coronary optical frequency domain imaging

Peri-stent contrast staining and late acquired malapposition represent pathological vessel wall healing patterns following percutaneous coronary intervention with stent implantation. Earlier studies have described these abnormal vessel wall responses commonly present after implantation of first-generation drug-eluting stents. These coronary vascular changes can cause flow disturbance and thereby dispose for later thrombotic events. This case report, based on coronary optical frequency domain imaging, describes peri-stent contrast staining, major evaginations and severe malapposition occurring 18months after third-generation biolimus-eluting stent implantation.

A Randomized Comparison between Everolimus-Eluting Stent and Cobalt Chromium Stent in Patients with Acute ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention Using Routine Intravenous Eptifibatide: The X-MAN (Xience vs. Multi-Link Stent in Acute Myocardial Infarction) Trial, A Pilot Study

The objective of this study is to determine the efficacy and safety of an everolimus-eluting stent (EES/Xience; Abbott Vascular, Santa Clara, CA) compared with a cobalt chromium stent (CoCr/Multi-Link Vision; Abbott Vascular) in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) with routine administration of eptifibatide infusion. This is a prospective, single center, randomized trial comparing EES (n = 75) and CoCr stent (n = 75) implantation in patients with acute STEMI undergoing primary PCI. Intravenous eptifibatide administration was mandatory by protocol in this pilot study. The primary efficacy endpoint was major adverse cardiac events (MACE) at 30 days, defined as the composite of death, reinfarction, and target vessel revascularization. Secondary safety endpoints were stent thrombosis at 30 days and in-hospital bleeding event. Acute reperfusion parameters were also assessed. One-month MACE rate did not differ between EES and CoCr group (1.3 vs. 1.3%, p = 1.0). No stent thrombosis cases were observed in the EES group. The groups did not differ with respect to in-hospital bleeding events (5 vs. 9%, p = 0.37), achievement of final thrombolysis in myocardial infarction flow 2 or 3 (p = 0.21), achievement of myocardial blush grade 2 or 3 (p = 0.45), creatine kinase-MB level at 8 to 12 hours after stenting (p = 0.29), and left ventricular ejection fraction (p = 0.21). This pilot study demonstrates that after one-month follow-up, the use of EES is as safe and effective as the use of CoCr stents in patients with acute STEMI undergoing primary PCI with routine administration of intravenous eptifibatide.