Determinants and long-term outcomes of largely uncovered struts in thin-struts drug-eluting stents assessed by optical coherence tomography

BACKGROUND

Uncovered struts are a determinant of stent failure. The impact of plaque composition and procedural factors on the occurrence, evolution, and outcomes of uncovered struts in a high-risk setting has not been investigated.

OBJECTIVE

To investigate the determinants and long-term clinical impact of largely uncovered struts (LUS) in thin-struts drug-eluting stents (DES) implanted in complex lesions by intracoronary optical coherence tomography (OCT).

METHODS

Ninety patients with multivessel disease undergoing staged complete revascularization were randomly assigned to bioabsorbable or durable polymer DES. OCT were serially performed during the index procedure, at 3- and 18-month follow-up, and analyzed by an independent core lab. Struts were defined uncovered by OCT if no tissue was visible above the struts. LUS were defined as ≥30% of uncovered struts at 3-month follow-up. Clinical outcomes were the occurrence of target vessel failure (TVF) and major adverse cardiac and cerebrovascular events (MACCE) at 5-year follow-up.

RESULTS

LUS occurred in 31 patients (34.4%) regardless of stent platform. At 5 years, no differences were observed in the rate of TVF (12.7% vs. 13.4%; p = 0.91) and MACCE (23.9% vs. 24.9%; p = 0.88) between the two groups. At multivariate logistic regression, plaque rupture, mean lumen diameter, proximal reference vessel area, and maximum stent deployment pressure were independent predictors of LUS.

CONCLUSIONS

LUS are a frequent finding in complex coronary lesions treated with thin-struts DES, especially in the presence of plaque rupture. However, in this study, no significant safety signal related to LUS emerged in long-term follow-up.

Optical Coherence Tomography to Assess Proximal Side Optimization Technique in Crush Stenting

Aim

The aim of this study was to explore the potential intraprocedural benefits of the Proximal Side Optimization (PSO) technique by Optical Coherence Tomography (OCT).

Methods

A case series of 10 consecutive true bifurcation lesions, with severe long pathology of long side branch (SB), were randomly assigned to be treated by standard DK Crush procedure (non-PSO group) as compared to DK Crush in PSO modification (PSO group). The data from OCT investigation before crushing of the SB Drug-Eluting Stent (DES), after crushing, after first kissing balloon inflation (KBI), and after final angiography were compared between the two groups (Public trials registry ISRCTN23355755).

Results

All 10 cases were successfully treated by the assigned technique. The two groups were similar in terms of indications for the procedure, bifurcation angle, and stent dimensions. As compared to the non-PSO, the PSO group showed larger proximal SB stent areas (5.8 ± 1.8 vs. 4.5 ± 0.5 mm²; p = 0.02), the larger delta between distal and proximal stent areas before crush (1.5 ± 0.7 vs. 0.6 ± 0.5 mm²; p = 0.004), and the larger Space of Optimal Wiring (SOW) after Crush (5.3 ± 1.8 vs. 2.5 ± 1.1 mm²; p = 0.02). The gaps in scaffolding within the ostial segment of the Side Branch DES were found in two patients from the non-PSO group.

Conclusion

The DK Crush in PSO modification results in larger SB DES and SOW areas with better apposition to the vessel wall. As result, the SB DES acquires a funnel shape, which reduces the risk of passage outside the SB stent struts during re-wiring, thus, allowing predictable and secure results.

Coronary Artery Perforation, Subepicardial Hematoma, and Cardiac Tamponade After Complex Percutaneous Coronary Intervention

This report presents the case of fissured subepicardial hematoma and cardiac tamponade after coronary artery perforation during a complex percutaneous intervention. Surgical therapy was required to achieve hemostasis because a percutaneous sealing result was insufficient. Prompt recognition and cardiac surgery availability are essential for patient survival in such situations. (Level of Difficulty: Beginner.).

Incidence, mechanisms and clinical impact of largely uncovered struts in current generation drug-eluting-stents: insight from the TRANSFORM-OCT Study

Background

Thin-strut drug-eluting stents (DES) and optimal implantation technique reduce the rate of stent failure significantly. Nevertheless, uncovered struts (US) have been observed as a key factor for stent thrombosis regardless of stent generation and time of follow-up. Associated factors and temporal evolution are currently unknown.

Purpose

To evaluate the prevalence, mechanisms and long-term clinical impact of largely-US after state-of-the-art DES implantation in complex coronary clinical/lesion cohorts

Methods

The study was a pre-specified analysis of TRASFORM-OCT, a randomized controlled trial comparing bioabsorbable or durable polymer DES by serial optical coherence tomography (OCT), obtained at baseline, immediately after procedure, at 3 and 18 months follow-up. Methods and results were published previously. For the current analysis enrolled patients (n=90) were divided in 2 groups according to the amount of US identified by OCT at 3 months: a largely US (LUS ≥30%) group and the control group (<30% US), to evaluate factors associated to LUS, and the clinical impact at follow-up.

Results

Out of 90 patients, 31 (34.4%) were assigned to the LUS group, and 59 (65.6%) to the control group. At baseline, LUS patients had larger vessels (reference area 5.51±1.1 vs. 4.27±1.5 mm2, p=0.001), a higher rate of plaque rupture (41.9 vs. 18.6%, p=0.02), thin-cap fibroatheroma (58.1% vs. 51.7% p=0.03) and thrombus (58.1% vs. 35.6%, p=0.001) as detected by OCT. 98% patients continued dual antiplatelet therapy up to 12 months, and 24% of them up to 18 months.

At stent implant, performed with high pressure dilation (21.18±3.8 vs 20.54±3.6 atm in LUS vs control group, p 0.48), the rate of apposed and embedded struts was high in both groups, although higher in controls (93.92±5.30% vs 96.46±3.68%, p 0.03 and 16.8±11.5% vs 21.7±15.8%, p=0.12, respectively for controls and LUS). At 3 months, US rate was 48.4±12% in the LUS group, and 13.3±7% in the control group (p<0.001). Global malapposition rate was 7.95±7.5% and 1.69±1.6% (p<0.001), respectively. 84.52±12.41% of the US in the LUS group and 86.49±19.98% in controls group were apposed to the wall (p 0.07). At 18 months, the rate of US dropped significantly to 8.4±10% in LUS group and 1.8±3% in control group (p<0.001), with malapposition rate being 1.4±3.3 and 0.16±0.43% (p 0.006). Of the US, 81.6±25.15 and 91.11±21.76% were apposed to the wall, respectively. At 5 years clinical follow-up, no differences were observed at the composite endpoint of major adverse cardiovascular events (detailed data will be presented).

Conclusions

In a setting of optimal PCI with modern DES and high-pressure inflation, LUS occur in 30% of patients at early follow-up, more frequently in large vessels with lipid-rich, complex plaques. The vast majority of US is apposed to the wall and near-complete coverage is observed at long-term follow-up, with no clinical impact compared to subjects with a low rate of US.

Funding Acknowledgement

Type of funding source: None

Analysis of the Amount of Polyphenols, Flavonoids and Assessment of the Antioxidant Capacity of Frozen Fruits

The data from literature shows that frozen vegetal products preserve their nutritional qualities for a long time. Fruits have a high content of substances with antioxidant capacity in the body. There are many recent studies demonstrating the importance of antioxidant substances in neutralizing free radicals in the human body. In this study there were analysed phenolic compounds and flavonoids in eight different species of fruits, belonging to three families. The antioxidant capacity of the extracts was evaluated by: CUPRAC assay, ABTS method and FRAP method. Our results show that the studied fruits represent rich sources of compounds with antioxidant capacity.

Correlations Between Oxidative Stress and Apoptosis During Anuran Metamorphosis

The living organisms can trigger the defense mechanisms against free radicals, by synthesizing different antioxidant enzymes. The present study is focused on establishing some correlation between oxidative stress and the structural changes in cell death at the intestinal larval epithelium level during anuran metamorphosis. Cell death in such conditions may be regarded as the result of an interaction activity in which takes place apoptosis, autophagy, and necrosis, the cell choosing one or more. The amphibian metamorphosis is a complex process, divided into three major periods: prometamorphosis, premetamorphosis and climax. The process ensures the passage of the organism from aquatic to terrestrial life, with dramatic changes in the morphology and structure of some organs. In the climax stages of metamorphosis, a variety of free radicals are produced, starting a numerous cellular oxidation reactions.

Perioperative management of oral antiplatelet therapy and clinical outcomes in coronary stent patients undergoing surgery

The aim was to investigate the perioperative risk of ischaemic and bleeding events in patients with coronary stents undergoing cardiac and non-cardiac surgery and how these outcomes are affected by the perioperative use of oral antiplatelet therapy. This was a multicentre, retrospective, observational study conducted in patients with coronary stent(s) undergoing cardiac or non-cardiac surgery. The primary efficacy endpoint was the 30-day incidence of major adverse cardiac events (MACE), defined as the composite of cardiac death, myocardial infarction (MI) or stroke. The primary safety endpoint was the 30-day incidence of Bleeding Academic Research Consortium (BARC) bleeding ≥ 2. A total of 666 patients were included. Of these, 371 (55.7 %) discontinued their antiplatelet medication(s) (all or partly) before undergoing surgery. At 30 days, patients with perioperative discontinuation of antiplatelet therapy experienced a significantly higher incidence of MACE (7.5 % vs 0.3 %, p < 0.001), cardiac death (2.7 % vs 0.3 %, p=0.027), and MI (4.0 % vs 0 %, p < 0.001). After adjustment, peri-operative antiplatelet discontinuation was the strongest independent predictor of 30-day MACE (odds ratio [OR]=25.8, confidence interval [CI]=3.37–198, p=0.002). Perioperative aspirin (adjusted OR 0.27, 95 % CI 0.11–0.71, p=0.008) was significantly associated with a lower risk of MACE. The overall incidence of BARC ≥ 2 bleeding events at 30-days was significantly higher in patients who discontinued oral antiplatelet therapy (25.6 % vs 13.9 %, p < 0.001). However, after adjustment, antiplatelet discontinuation was not independently associated with BARC ≥ 2 bleeding. In conclusion antiplatelet discontinuation increases the 30-day risk of MACE, in patients with coronary stents undergoing cardiac and non-cardiac surgery, while not offering significant protection from BARC≥ 2 bleeding.

Optical Coherence Tomography Findings in Patients With Coronary Stent Thrombosis: A Report of the PRESTIGE Consortium (Prevention of Late Stent Thrombosis by an Interdisciplinary Global European Effort)

BACKGROUND

Stent thrombosis (ST) is a serious complication following coronary stenting. Intravascular optical coherence tomography (OCT) may provide insights into mechanistic processes leading to ST. We performed a prospective, multicenter study to evaluate OCT findings in patients with ST.

METHODS

Consecutive patients presenting with ST were prospectively enrolled in a registry by using a centralized telephone registration system. After angiographic confirmation of ST, OCT imaging of the culprit vessel was performed with frequency domain OCT. Clinical data were collected according to a standardized protocol. OCT acquisitions were analyzed at a core laboratory. Dominant and contributing findings were adjudicated by an imaging adjudication committee.

RESULTS

Two hundred thirty-one patients presenting with ST underwent OCT imaging; 14 (6.1%) had image quality precluding further analysis. Of the remaining patients, 62 (28.6%) and 155 (71.4%) presented with early and late/very late ST, respectively. The underlying stent type was a new-generation drug-eluting stent in 50.3%. Mean reference vessel diameter was 2.9±0.6 mm and mean reference vessel area was 6.8±2.6 mm². Stent underexpansion (stent expansion index <0.8) was observed in 44.4% of patients. The predicted average probability (95% confidence interval) that any frame had uncovered (or thrombus-covered) struts was 99.3% (96.1-99.9), 96.6% (92.4-98.5), 34.3% (15.0-60.7), and 9.6% (6.2-14.5) and malapposed struts was 21.8% (8.4-45.6), 8.5% (4.6-15.3), 6.7% (2.5-16.3), and 2.0% (1.2-3.3) for acute, subacute, late, and very late ST, respectively. The most common dominant finding adjudicated for acute ST was uncovered struts (66.7% of cases); for subacute ST, the most common dominant finding was uncovered struts (61.7%) and underexpansion (25.5%); for late ST, the most common dominant finding was uncovered struts (33.3%) and severe restenosis (19.1%); and for very late ST, the most common dominant finding was neoatherosclerosis (31.3%) and uncovered struts (20.2%). In patients presenting very late ST, uncovered stent struts were a common dominant finding in drug-eluting stents, and neoatherosclerosis was a common dominant finding in bare metal stents.

CONCLUSIONS

In patients with ST, uncovered and malapposed struts were frequently observed with the incidence of both decreasing with longer time intervals between stent implantation and presentation. The most frequent dominant observation varied according to time intervals from index stenting: uncovered struts and underexpansion in acute/subacute ST and neoatherosclerosis and uncovered struts in late/very late ST.

Study of the Plasmatic Oxidative Stress Markers in Temporomandibular Joint Disorders

Oxidative stress is considered to have an important role in the pathogenesis of many inflammatory diseases. This investigation sought to determine whether the appliance of etiologic factors for temporomandibular joint disorder is associated with modified values of oxidative stress as measured by biomarkers in plasma. A case-control study design was used to compare oxidative stress biomarkers (malondialdehyde and glutathione) in plasma from Wistar rats with different etiologic factors (biomechanical stress, estrogen hormones and emotional stress), compared to non-temporomandibular joint controls. Etiologic factors were applied in five groups (n=10) of mature female Wistar rats, individually (biomechanical stress, estrogen hormones and emotional stress) in three groups or in combination for two groups (biomechanical stress-emotional stress and biomechanical stress-emotional stress). No factor applied for the control group. Blood samples were taken after 30 and 60 days of experiment. Malondialdehyde and glutathione levels in plasma were evaluated. The most important modifications in malondialdehyde levels were recorded for the fifth group (biomechanical stress-emotional stress) where values increased significantly from 30 to 60 days plasma analysis (p = 0.003). No statistical differences were recorded in glutathione plasmatic levels between control and experimental groups at 30 days analysis. At 60 days, glutathione plasmatic evaluation recorded higher values than control for all experimental groups. Our findings in this rat experimental model, clearly indicate that biomechanical stress, estrogen hormones and emotional stress, have an impact on oxidative stress development and consequently on the functionality of the temporomandibular joint in rats. Moreover combined actions of these factors, increase the oxidative stress phenomena on temporomandibular joint in rats.

Comparative Analysis upon Action of Aqueous and Alcoholic Trigonella sp. Extracts on Fibroblasts Culture

Flow cytometry with its numerous advantages, has become indispensable for modern biochemistry research, being a highly efficient and sensitive in many areas, particularly in the fundamental or applied cellular biology. Flow cytometry has greatly contributed to the exploration of the cellular structure and functions, combining analytical and preparative aspects. In combination with the use of the probes (fluorochromes, fluorogenic substrates, monoclonal antibodies and lectins), the FCM enables multiple investigations for the characterization of cellular populations, the analysis of the cellular components (nucleic acids, proteins, intercellular and surface antigens, enzyme activities, membrane potential, mitochondrial activity, intracellular pH, ion flux and membrane fluidity). We chose to study the behavior of fibroblasts using flow cytometry, in terms of effects induced by the presence of extracts from Trigonella foenum graecum L.

Malondialdehyde and Lipofuscin Biomarkers of Oxidative Stress in Rana temporaria temporaria During Metamorphosis

Anuran amphibians metamorphosis represents a model for the study of different processes, including tissue remodeling. One of the body�s systems whose morphological and structural properties are deeply transformed during metamorphosis is the digestive tract. The only structure in the digestive tract which is destroyed and then replaced with a new tissue (histolysis and histogenesis) under the action of oxidative stress and hormones, is the intestinal epithelium. Oxidative stress may be related to the production of malondialdehyde and the accumulation of lipofuscin. The two substances can be considered biomarkers of this process.

Relationship between Serum Inflammatory Biomarkers and Thrombus Characteristics in Patients with ST Segment Elevation Myocardial Infarction

Objectives: To compare angiographic and optical coherence tomography (OCT) data pertinent to thrombi, along with the histologic characteristics of aspirated thrombi in patients presenting with ST elevation myocardial infarction (STEMI) with or without inflammation, as assessed by C-reactive protein (CRP) and myeloperoxidase (MPO). Methods: In the OCTAVIA (Optical Coherence Tomography Assessment of Gender Diversity in Primary Angioplasty) study, 140 patients with STEMI referred for primary percutaneous intervention were enrolled. The patients underwent OCT assessment of the culprit vessel, along with blood sampling of CRP and MPO, and histologic analysis of the thrombus. Results: Biomarkers were available for 129 patients, and histology and immunohistochemistry of the thrombi were available for 78 patients. Comparisons were made using the median thresholds of CRP and MPO (2.08 mg/L and 604.124 ng/mL, respectively). There was no correlation between CRP and MPO levels in the whole population (p = 0.685). Patients with high CRP levels had higher thrombus grades and more frequent TIMI flow 0/1 compared with those with low CRP levels (5 [1st quartile 3; 3rd quartile 5] vs. 3.5 mg/L [1; 5], p = 0.007, and 69.3 vs. 48.5%, p = 0.04, respectively). Patients with high MPO levels more commonly had early thrombi than had those with low MPO levels (42.5 vs. 20.0%, p = 0.04). Conclusions: CRP and MPO were not correlated in STEMI patients, possibly reflecting different pathogenic mechanisms, with CRP more related to thrombus burden and MPO to thrombus age.

Percutaneous Coronary Intervention Planning and Optimization with Optical Coherence Tomography

Coronary angiography confirms or excludes coronary artery disease, assesses lesions severity, and helps to decide percutaneous coronary interventions (PCI). Coronary angiography has clear limitations. Intravascular imaging guides PCI. Frequency domain optical coherence tomography (OCT) gained attention for accurate planning and guidance of complex PCI. High-speed OCT image acquisition enables prompt vessel assessment in stable and unstable patients. The high-resolution images provide precise tissue characterization and a reliable quantitative assessment of the coronary pathology. Immediately after stent implantation, OCT allows accurate evaluation of stent expansion and symmetry. Real-time angio-OCT co-registration integrates OCT into the PCI workflow for accurate decision making.

Eroded Versus Ruptured Plaques at the Culprit Site of STEMI: In Vivo Pathophysiological Features and Response to Primary PCI

OBJECTIVES

The aim of this study was to evaluate the pathophysiological features and response to primary percutaneous coronary intervention (PCI) of nonruptured/eroded plaque versus ruptured plaque as a cause of ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Autopsy series identified nonruptured/eroded plaque and ruptured plaque as the principal pathological substrates underlying coronary thrombosis in STEMI. The real incidence of different plaque morphologies, associated biological factors, superimposed thrombus, and their interaction with primary PCI remain largely unknown.

METHODS

In a prospective study, 140 patients with STEMI underwent optical coherence tomography of the infarct-related artery (IRA) before PCI, after everolimus-eluting stent implantation and at 9-month follow-up. Histopathology and immunohistochemistry of thrombus aspirates and serum biomarkers were assessed at baseline.

RESULTS

Culprit plaque morphology was adjudicated in 97 patients: 32 plaques (33.0%) with an intact fibrous cap (IFC), 63 (64.9%) plaques with a ruptured fibrous cap (RFC), and 2 (2.1%) spontaneous dissections. Patients with an IFC and RFC had similar clinical characteristics, and serum inflammatory and platelets biomarkers. An IFC presented more frequently with a patent IRA (56.2% vs. 34.9%; p = 0.047), and had fewer lipid areas (lipid-rich areas: 75.0% vs. 100.0%; p < 0.001) and less residual thrombus before stenting (white thrombus: 0.41 mm(3) vs. 1.52 mm(3); p = 0.001; red thrombus: 0 mm(3) vs. 0.29 mm(3); p = 0.001) with a lower peak of creatine kinase-myocardial band (66.6 IU/l vs. 149.8 IU/l; p = 0.025). At the 9-month optical coherence tomography, IFC and RFC had similar high rates of stent strut coverage (92.5% vs. 91.2%; p = 0.15) and similar percentage of volume obstruction (12.6% vs. 10.2%; p = 0.27). No significant differences in clinical outcomes were observed up to 2 years.

CONCLUSIONS

In the present study, an IFC was observed at the culprit lesion site of one-third of STEMIs. IFC, compared with RFC, was associated with higher rates of patent IRA at first angiography, fewer lipid areas, and residual endoluminal thrombus. However, no difference in vascular response to everolimus-eluting stent was observed. (Optical Coherence Tomography Assessment of Gender Diversity in Primary Angioplasty [OCTAVIA]; NCT01377207).

Optical coherence tomography versus intravascular ultrasound to evaluate coronary artery disease and percutaneous coronary intervention

OBJECTIVES

We compared intravascular ultrasound (IVUS) and 2 different generations of optical coherence tomography (OCT)-time-domain OCT (TD-OCT) and frequency-domain OCT (FD-OCT)-for the assessment of coronary disease and percutaneous coronary intervention (PCI) using stents.

BACKGROUND

OCT is a promising light-based intravascular imaging modality with higher resolution than IVUS. However, the paucity of data on OCT image quantification has limited its application in clinical practice.

METHODS

A total of 227 matched OCT and IVUS pull backs were studied. One hundred FD-OCT and IVUS pull backs in nonstented (n = 56) and stented (n = 44) vessels were compared. Additionally, 127 matched TD-OCT and IVUS images were compared in stented vessels.

RESULTS

FD-OCT depicted more severe native coronary disease than IVUS; minimal lumen area (MLA) was 2.33 ± 1.56 mm(2) versus 3.32 ± 1.92 mm(2), respectively (p < 0.001). Reference vessel dimensions were equivalent between FD-OCT and IVUS in both native and stented coronaries, but TD-OCT detected smaller reference lumen size compared with IVUS. Immediately post-PCI, in-stent MLAs were similar between FD-OCT and IVUS, but at follow-up, both FD-OCT and TD-OCT detected smaller MLAs than did IVUS, likely due to better detection of neointimal hyperplasia (NIH). Post-PCI malapposition and tissue prolapse were more frequently identified by FD-OCT.

CONCLUSIONS

FD-OCT generates similar reference lumen dimensions but higher degrees of disease severity and NIH, as well as better detection of malapposition and tissue prolapse compared with IVUS. First-generation TD-OCT was associated with smaller reference vessel dimensions compared with IVUS.

Volumetric assessment of lesion severity with optical coherence tomography: relationship with fractional flow

AIMS

Frequency-domain optical coherence tomography (FD-OCT) provides a rapid tomographic scan of a coronary vessel, with an accurate reconstruction of its lumen profile. An FD-OCT-based metric that corresponds more closely with physiological significance of lesions may enable more precise guidance of interventional procedures. The aim of this feasibility study was to evaluate a new method for quantifying coronary lesion severity that estimates hyperaemic flow resistance of branched vessel segments imaged by FD-OCT.

METHODS AND RESULTS

An analytical flow model was developed that relates fractional flow reserve (FFR) to the vascular resistance ratio (VRR), a measure of blood flow resistance derived from volumetric FD-OCT lumen profiles. The VRR-FFR relationship was evaluated in 21 patients on whom both pressure measurement and FD-OCT imaging were performed in a random order during maximal hyperaemia. Lesion severity assessed by VRR showed a stronger linear correlation with FFR measurements (before model optimisation [blinded]: r=0.81; p<0.001; root mean square error [RMSE]=0.095 FFR units; after model optimisation [unblinded]: r=0.91; p<0.001; RMSE=0.066 FFR units) than quantitative coronary angiography and FD-OCT-derived measurements of minimum lumen area (r=0.67; p=0.0012) and per cent area stenosis (r=-0.61; p=0.004).

CONCLUSIONS

Accurate volumetric measurement of the lumen profile with FD-OCT correlates more closely with FFR than standard metrics derived from single image cross-sections. VRR shows promise as a method for evaluating lesion severity.

Optical coherence tomography evidence of endothelial erosion as a cause of ST-segment elevation myocardial infarction

High-resolution intracoronary imaging provided relevant insights into the field of pathophysiology of acute coronary syndromes (ACS). Human autopsy studies have shown that endothelial erosion may lead to intravascular thrombosis and acute myocardial infarction. We report the case of a 51-year-old woman presenting with ST-segment elevation ACS. In this patient, frequency domain optical coherence tomography (FD-OCT) was performed into the infarct-related artery, showing in-vivo findings suggestive of endothelial erosion, associated with no flow-obstructing luminal thrombus. In this rare case, endothelial erosion, and subsequent thrombosis, in the proximal third of the artery has probably caused embolization and thrombotic occlusion in the mid third. FD-OCT allowed us to obtain a rare in-vivo image of endothelial erosion, providing relevant insights into the setting of ACS.

Examination of the in vivo mechanisms of late drug-eluting stent thrombosis: findings from optical coherence tomography and intravascular ultrasound imaging

OBJECTIVES

This study investigated the role of uncovered stent struts on late stent thrombosis (LST) after drug-eluting stent (DES) implantation with optical coherence tomography (OCT).

BACKGROUND

Autopsy studies have identified delayed healing and lack of endothelialization of DES struts as the hallmarks of LST. DES strut coverage has not previously been examined in vivo in patients with LST.

METHODS

We studied 54 patients, including 18 with DES LST (median 615 days after implant) undergoing emergent percutaneous coronary interventions and 36 matched DES control subjects undergoing routine repeat OCT and intravascular ultrasound (IVUS) who did not experience LST for ≥3 years. Thrombus aspiration was performed during emergent percutaneous coronary intervention before OCT and IVUS assessment.

RESULTS

By OCT, patients with LST--compared with control subjects--had a higher percentage of uncovered (median [interquartile range]) (12.27 [5.50 to 23.33] vs. 4.14 [3.00 to 6.22], p < 0.001) and malapposed (4.60 [1.85 to 7.19] vs. 1.81 [0.00 to 2.99], p < 0.001) struts. The mean neointimal thickness was similar in the 2 groups (0.23 ± 0.17 mm vs. 0.17 ± 0.09 mm, p = 0.28). By IVUS, stent expansion was comparable in the 2 groups, although positive remodeling was increased in patients with LST (mean vessel cross-section area 19.4 ± 5.8 mm(2) vs. 15.1 ± 4.6 mm(2), p = 0.003). Thrombus aspiration demonstrated neutrophils and eosinophils in most cases. By multivariable analysis, the length of segment with uncovered stent struts by OCT and the remodeling index by IVUS were independent predictors of LST.

CONCLUSIONS

In this in vivo case-controlled study, the presence of uncovered stent struts as assessed by OCT and positive vessel remodeling as imaged by IVUS were associated with LST after DES.

Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies: a report from the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation

OBJECTIVES

The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease.

BACKGROUND

Intravascular optical coherence tomography (IVOCT) is a catheter-based modality that acquires images at a resolution of ~10 μm, enabling visualization of blood vessel wall microstructure in vivo at an unprecedented level of detail. IVOCT devices are now commercially available worldwide, there is an active user base, and the interest in using this technology is growing. Incorporation of IVOCT in research and daily clinical practice can be facilitated by the development of uniform terminology and consensus-based standards on use of the technology, interpretation of the images, and reporting of IVOCT results.

METHODS

The IWG-IVOCT, comprising more than 260 academic and industry members from Asia, Europe, and the United States, formed in 2008 and convened on the topic of IVOCT standardization through a series of 9 national and international meetings.

RESULTS

Knowledge and recommendations from this group on key areas within the IVOCT field were assembled to generate this consensus document, authored by the Writing Committee, composed of academicians who have participated in meetings and/or writing of the text.

CONCLUSIONS

This document may be broadly used as a standard reference regarding the current state of the IVOCT imaging modality, intended for researchers and clinicians who use IVOCT and analyze IVOCT data.

Prevalence, predictors, and long-term prognosis of premature discontinuation of oral antiplatelet therapy after drug eluting stent implantation

To date, limited information is available on the long-term discontinuation rates of antiplatelet therapy after drug-eluting stent implantation. The aim of the present study was to determine the prevalence and predictors of premature discontinuation of oral antiplatelet therapy after drug-eluting stent implantation and to evaluate its effects on long-term prognosis. We studied 1,358 consecutive patients successfully treated with drug-eluting stents and discharged with dual oral antiplatelet therapy. Aspirin was to be maintained lifelong, and clopidogrel was prescribed for 12 months. The patients were followed for 36 months. The prevalence and predictors of aspirin and clopidogrel discontinuation were assessed. Major adverse cardiac events, defined as death, myocardial infarction, destabilizing symptoms leading to hospitalization, and nonfatal stroke, were recorded. Definite, probable, and possible stent thrombosis (ST) and major and minor bleeding were also determined. Of the 1,358 patients, 8.8% had discontinued one or both antiplatelet agents within the first 12 months ("early" discontinuation) and 4.8% had discontinued aspirin after 1 year ("late" discontinuation). Early discontinuation was predicted by in-hospital major bleeding, the use of oral anticoagulants at discharge, and the lack of a statin prescription. Previous stroke was the only independent predictor of late discontinuation. Patients with early discontinuation experienced a greater incidence of major adverse cardiac events (28.6% vs 13.7%, p <0.001) and ST (7.6% vs 3.4%, p = 0.038). All-cause mortality (13.4% vs 4.7%, p <0.001) and cardiovascular death (5% vs 1.2%, p = 0.007) were significantly more frequent among patients with early discontinuation. In patients with late discontinuation, a nonstatistically significant increase was seen in major adverse cardiac events (20% vs 13.3%, p = 0.128) and ST (6.2% vs 3.2%, p = 0.275). In conclusion, premature discontinuation of antiplatelet therapy is relatively common, especially within the first year, and strongly associated with increased cardiovascular events, including ST and death.

Strut coverage and late malapposition with paclitaxel-eluting stents compared with bare metal stents in acute myocardial infarction: optical coherence tomography substudy of the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) Trial

BACKGROUND

The safety of drug-eluting stents in ST-segment elevation myocardial infarction (STEMI) continues to be debated. Pathological studies have demonstrated an association between uncovered struts and subsequent stent thrombosis. Optical coherence tomography can detect stent strut coverage in vivo on a micron-scale level. We therefore used optical coherence tomography to examine strut coverage in patients with STEMI treated with paclitaxel-eluting stents (PES) and bare metal stents (BMS).

METHODS AND RESULTS

In the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, patients with STEMI were randomized 3:1 to PES or BMS implantation. In a formal substudy, optical coherence tomography at 13 months was performed in 118 consecutive randomized patients (89 PES, 29 BMS) in whom 188 stents were assessed (146 PES and 42 BMS). A total of 44 139 stent struts were analyzed by an independent core laboratory blinded to stent assignment. The primary prespecified end point, the percentage of uncovered stent struts per lesion at follow-up, was 1.1 ± 2.5% in BMS lesions versus 5.7 ± 7.0% in PES lesions (P < 0.0001). Malapposed struts were observed in 0.1 ± 0.2% of BMS lesions versus 0.9 ± 2.1% of PES lesions (P = 0.0003). Percentage net volume obstruction was 36.0 ± 15.4% with BMS and 19.2 ± 11.3% with PES (P < 0.0001).

CONCLUSIONS

In patients with STEMI undergoing primary percutaneous coronary intervention, implantation of PES as compared with BMS significantly reduces neointimal hyperplasia but results in higher rates of uncovered and malapposed stent struts as assessed by optical coherence tomography at 13-month follow-up. Further studies are required to determine the clinical significance of these findings.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00433966.

Optical coherence tomography in ST-elevation myocardial infarction treated with novel drug-eluting stent: preprocedural, postimplant and 2-month follow-up findings

The use of drug-eluting stents (DES) allowed the reduction in the need for repeat revascularization. At the culprit site in acute myocardial infarction patients treated with first-generation DES, the interaction between the eluted drug and the underlying necrotic core may generate different patterns of pathologic vessel response and delayed healing. A new generation DES intrepide elutes trapidil. Its modes of action are neither cytotoxic nor cytostatic, and may promote normal re-endothelialization. Due to its high resolution, optical coherence tomography (OCT) allows accurate detection of thrombus deposition and stent strut coverage at follow-up. Intravascular ultrasound (IVUS) has enhanced tissue penetration and provides information on vessel remodeling. Using OCT and IVUS, we evaluated the intravascular morphology of the culprit vessel, the acute and intermediate result of novel DES implanted to treat an ST-segment elevation myocardial infarction.

Strut coverage and vessel wall response to zotarolimus-eluting and bare-metal stents implanted in patients with ST-segment elevation myocardial infarction: the OCTAMI (Optical Coherence Tomography in Acute Myocardial Infarction) Study

OBJECTIVES

Using optical coherence tomography, we assessed the proportion of uncovered struts at 6-month follow-up in zotarolimus-eluting stents (ZES), specifically Endeavor (Medtronic CardioVascular, Santa Rosa, California) stents, and identical bare-metal stents (BMS) implanted in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Sirolimus- and paclitaxel-eluting stents implanted in STEMI have been associated with delayed healing and incomplete strut coverage. ZES are associated with a more complete and uniform strut coverage in stable patients, but whether this holds true also after STEMI is unknown.

METHODS

Forty-four patients with STEMI who underwent primary PCI were randomized to ZES or BMS (3:1 randomization). Angiographic, intravascular ultrasound, and optical coherence tomography follow-up was conducted at 6 months and clinical follow-up at 1 year. All images were analyzed by an independent core laboratory that was blind to stent assignments.

RESULTS

There were no differences between ZES and BMS in percentage of uncovered struts (median: 0.00% [interquartile range (IQR): 0.00% to 1.78%] vs. 1.98% [IQR: 0.21% to 7.33%], p = 0.13), maximum length of uncovered segments (0.00 [IQR: 0.00 to 1.19] mm vs. 1.38 [IQR: 0.65 to 3.30] mm, p = 0.10), percentage of malapposed struts (0.00% [IQR: 0.00% to 0.23%] vs. 0.15% [IQR: 0.00% to 5.81%], p = 0.16), and maximum length of malapposed segments (0.00 [IQR: 0.00 to 0.67] mm vs. 0.33 [IQR: 0.00 to 2.55] mm, p = 0.20). Neointimal response was similar between ZES and BMS (332 [IQR: 240 to 429] microm vs. 186 [IQR: 136 to 348] microm, p = 0.99) and evenly distributed. No late acquired malapposition was observed in both groups. There were no deaths, myocardial infarction, or stent thromboses at 1 year.

CONCLUSIONS

This optical coherence tomography study found no difference in strut coverage and similar vessel response to ZES, when compared with identical BMS, implanted during primary percutaneous coronary intervention in STEMI patients. (Six-Month Coverage and Vessel Wall Response of the Zotarolimus Drug-Eluting Stent Implanted in AMI Assessed by Optical Coherence Tomography [OCTAMI]; NCT00704561).

Optical coherence tomography assessment of in vivo vascular response after implantation of overlapping bare-metal and drug-eluting stents

OBJECTIVES

We designed a randomized trial exploiting optical coherence tomography (OCT) to assess coverage and apposition of overlapping bare-metal stents (BMS) and drug-eluting stents (DES) in human coronary arteries.

BACKGROUND

Overlapping DES impair healing in animals. Optical coherence tomography allows accurate in vivo assessment of stent strut coverage and apposition.

METHODS

Seventy-seven patients with long coronary stenoses were randomized to overlapping sirolimus-eluting stents (SES), paclitaxel-eluting stents (PES), zotarolimus-eluting stents (ZES), or BMS. The primary goal of the study was to determine the rate of uncovered/malapposed struts in overlap versus nonoverlap segments, according to stent type, at 6-month follow-up with OCT.

RESULTS

A total of 53,047 struts were analyzed. The rate of uncovered/malapposed struts was 1.5 +/- 3.4% and 0.6 +/- 2.7% in overlap versus nonoverlap BMS (p = NS), respectively, and 4.3 +/- 11% and 3.6 +/- 8% in overlap versus nonoverlap DES (p = NS), respectively. There were no differences in the rates of uncovered/malapposed struts between overlapping BMS and DES, likely due to low frequency of uncovered/malapposed struts in ZES (0.1 +/- 0.4%), which offset the higher rates observed in SES (6.7 +/- 9.6%) and PES (6.7 +/- 16.5%, p < 0.05). Overlap segments showed greater neointimal volume obstruction versus nonoverlap segments in all DES (p < 0.05 for all DES types). Strut-level neointimal thickness at overlap and nonoverlap segments were lowest in SES (0.16 +/- 0.1 mm and 0.12 +/- 0.1 mm, respectively) compared with PES (0.27 +/- 0.1 mm and 0.20 +/- 0.1 mm, respectively), ZES (0.40 +/- 0.16 mm and 0.33 +/- 0.13 mm, respectively), and BMS (0.55 +/- 0.31 mm and 0.53 +/- 0.25 mm, respectively, p < 0.05).

CONCLUSIONS

As assessed by OCT the impact of DES on vascular healing was similar at overlapping and nonoverlapping sites. However, strut malapposition, coverage pattern, and neointimal hyperplasia differ significantly according to DES type. (Optical Coherence Tomography for Drug Eluting Stent Safety [ODESSA]; NCT00693030).

Strut Coverage and Vessel Wall Response to a New-Generation Paclitaxel-Eluting Stent With an Ultrathin Biodegradable Abluminal Polymer

Background—

Polymer-coated drug-eluting stents are effective in preventing restenosis but have been associated with delayed healing and incomplete strut coverage. It is unknown whether paclitaxel-eluting stents (PES) with minimal biodegradable abluminal coating enhances strut coverage while preventing neointimal hyperplasia. Using optical coherence tomography (OCT) as a primary imaging modality, we assessed the proportion of uncovered struts at 6-month follow-up in PES coated with durable versus ultrathin (<1 μm) biodegradable abluminal polymers.

Methods and Results—

In this pilot trial, 60 patients with de novo lesions (≤25 mm) in native coronary vessels were randomly assigned to receive either TAXUS Liberté PES or JACTAX PES, a Liberté stent with polymer deposited abluminally as microdots (JACTAX HD: 9.2 μg each of polymer and paclitaxel per 16-mm stent; JACTAX LD: 5 μg each). OCT follow-up occurred at 6 months with clinical follow-up through 1 year. The primary end point was percent uncovered struts by OCT. An independent core laboratory blinded to stent assignment analyzed images. The 6-month rate of uncovered struts per patient was 5.3±14.7% for TAXUS Liberté, 7.0±12.2% for JACTAX HD, and 4.6±7.3% for JACTAX LD ( P =0.81); percent malapposed struts was 1.4±4.4%, 0.8±1.9%, and 1.1±2.8%, respectively ( P =0.86). Strut-level intimal thickness was 0.20±0.10, 0.22±0.15, and 0.24±0.15 mm ( P =0.64); percent volume obstruction by OCT was 22.2±12.8, 22.5±16.2, and 25.8±15.2 ( P =0.69). There were no deaths, Q-wave myocardial infarctions, or stent thromboses through 1 year.

Conclusions—

JACTAX PES with an ultrathin microdot biodegradable abluminal polymer did not result in improved strut coverage at 6 months compared with TAXUS Liberté.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00776204.

Optical coherence tomography (OCT) strut-level analysis of drug-eluting stents (DES) in human coronary bifurcations

AIMS

We sought to evaluate the vascular response of stent struts deployed in bifurcation segments using optical coherence tomography (OCT).

METHODS AND RESULTS

This study is a sub-analysis of ODESSA, a prospective randomised trial designed to evaluate healing of overlapped drug-eluting stents (DES) vs. bare metal stents (BMS) (sirolimus SES: paclitaxel PES: zotarolimus ZES: Liberté BMS in a 2: 2: 2: 1 ratio) for de novo coronary artery stenosis. OCT was performed at 6-month follow-up. Bifurcation segments with side branch diameters larger than 1.5mm by angiography were analysed. The cross-sectional image at the bifurcation segment was divided into three regions: opposite to the ostium (OO), adjacent to the ostium (AO), or side-branch ostium (SO). Struts were classified in three categories: uncovered (U), covered (C), or proliferative (P). The incidence of each strut category was compared between regions and stent types. There were 12,656 struts in 61 bifurcation segments (PES: 16, SES: 14, ZES: 23, Liberté BMS: 8) from 46 patients obtained at six months. PES had the highest rate of U in SO region (PES 60.1, SES 17.0, ZES 13.2, BMS 12.3 (%), P<0.0001), whereas SES demonstrated the highest rate of U in OO (PES 3.8, SES 14.0, ZES 1.5, BMS 0.0 (%), P=0.0025).

CONCLUSIONS

This study demonstrates a variable pattern of strut coverage in the bifurcation among stent technologies, with a high percentage of PES floating struts remaining uncovered at 6-month follow-up.

Long-term outcomes in patients undergoing coronary stenting on dual oral antiplatelet treatment requiring oral anticoagulant therapy

In patients undergoing coronary stenting, long-term dual antiplatelet therapy with aspirin and clopidogrel reduces atherothrombotic events but also increases the risk of bleeding. The potential for developing bleeding complications is further enhanced in patients also requiring oral anticoagulant treatment ("triple therapy"). The aim of the study is to assess long-term outcomes associated with the use of triple-therapy in patients undergoing coronary stenting and evaluate how these may be affected by targeting international normalized ratio (INR) values to the lower therapeutic range. We prospectively studied 102 consecutive patients undergoing coronary stenting treated with dual antiplatelet therapy also requiring oral anticoagulation. INR was targeted to the lower therapeutic range (2.0 to 2.5). Patients requiring oral anticoagulant therapy because of mechanical valve prosthesis were excluded. Patients were followed for 18 months, and bleeding, defined according to Thrombolysis in Myocardial Infarction criteria, and major adverse cardiac events were recorded. Outcomes were compared with a control group (n = 102) treated only with dual antiplatelet therapy. The mean duration of triple therapy was 157 +/- 134 days. At 18 months, a nonsignificant increase in bleeding was observed in the triple versus dual therapy group (10.8% vs 4.9%, p = 0.1). INR values were higher in patients with bleeding (2.8 +/- 1.1 vs 2.3 +/- 0.2, p = 0.0001). In patients who had INR values within the recommended target (79.4%), the risk of bleeding was significantly lower compared with patients who did not (4.9 vs 33%, p = 0.00019) and with that observed in the control group (4.9%). An INR >2.6 was the only independent predictor of bleeding. There were no significant differences in major adverse cardiac events between groups (5.8% vs 4.9%, p = 0.7). In conclusion, in patients undergoing coronary stenting on triple therapy, targeting lower therapeutic INR values reduces the risk of bleeding complications.