In-vivo assessment of vascular injury for the prediction of in-stent restenosis.

BACKGROUND: Despite optimizations of coronary stenting technology, a residual risk of in-stent restenosis (ISR) remains. Vessel wall injury has important impact on the development of ISR. While injury can be assessed in histology, there is no injury score available to be used in clinical practice. METHODS: Seven rats underwent abdominal aorta stent implantation. At 4 weeks after implantation, animals were euthanized, and strut indentation, defined as the impression of the strut into the vessel wall, as well as neointimal growth were assessed. Established histological injury scores were assessed to confirm associations between indentation and vessel wall injury. In addition, stent strut indentation was assessed by optical coherence tomography (OCT) in an exemplary clinical case. RESULTS: Stent strut indentation was associated with vessel wall injury in histology. Furthermore, indentation was positively correlated with neointimal thickness, both in the per-strut analysis (r = 0.5579) and in the per-section analysis (r = 0.8620; both p ≤ 0.001). In a clinical case, indentation quantification in OCT was feasible, enabling assessment of injury in vivo. CONCLUSION: Assessing stent strut indentation enables periprocedural assessment of stent-induced damage in vivo and therefore allows for optimization of stent implantation. The assessment of stent strut indentation might become a valuable tool in clinical practice.

Long-Term Intracoronary Structural and Vasomotor Assessment of the ABSORB Bioresorbable Vascular Scaffold.

We systematically categorized the longer-term (≥3 years) structural and functional characteristics of the ABSORB bioresorbable vascular scaffold (BVS) using optical coherence tomography imaging and coronary vasomotor reactivity testing and further compared the functional characteristics of BVS stented versus remote coronary segments. A total of 92 patients (mean age 56.4 ± 9.7 years, 22.8% women) who underwent percutaneous coronary intervention (76% with acute coronary syndrome) using the ABSORB BVS (112 lesions) were included. Optical coherence tomography analysis (38,790 visible struts) comprised in-segment quantitative lumen/plaque and semiquantitative plaque composition analysis of the neointimal pattern. Epicardial endothelium-dependent and-independent vasomotion was defined as any vasodilatation at low/intermediate intracoronary dose of acetylcholine (ACh) and nitroglycerine, assessed using quantitative coronary angiography. At a median time of 3.2 years follow-up, 79.8% of BVS segments still demonstrated visible struts with a predominant neointimal fibrotic healing pattern in 84% of BVS segments, with 99.5% of struts demonstrating coverage with apposition. Compared with remote segments, BVS segments demonstrated less endothelium-dependent vasodilatation at low (p = 0.06) and intermediate ACh doses (p = 0.04). Hypertension, longer time interval from index percutaneous coronary intervention, and the degree of in-BVS segment neointimal volume (p <0.03 for all) were each independently associated with abnormal BVS endothelium-dependent vasomotor function. Endothelium-independent function was more likely preserved in non-BVS (remote) segments compared with BVS segments (p = 0.06). In conclusion, at 3+ years post-ABSORB BVS insertion, the rate of complete scaffold resorption was low and residual strut presence was high, with a dominant fibrous healing response contributing toward neointimal hyperplasia and endothelium-dependent and-independent vasomotor dysfunction.

Preclinical Assessment of a Novel Conformable Foam-Based Left Atrial Appendage Closure Device.

BACKGROUND: Left atrial appendage (LAA) occlusion has been established as an alternative to systemic anticoagulation for stroke prevention in patients with atrial fibrillation; however, limitations of current devices have slowed adoption. We present preclinical evaluations of a novel device, the Conformal Left Atrial Appendage Seal (CLAAS). METHODS: An in vitro assessment of conformability was conducted to evaluate the two CLAAS devices (regular 27 mm and large 35 mm) and a Watchman 2.5 (27 mm). Devices were placed within silicone tubes and compressed in a vise submerged in a water bath at 37°C. Changes in device diameter and visual seal were noted. Acute (n = 1) and chronic 60-day (n = 6) canine studies with gross and histologic assessment were performed. RESULTS: Conformability bench tests demonstrated that the regular CLAAS implant was able to seal oval orifices from 20 × 30 mm to 15 × 33 mm and the large from 30 × 35 mm to 20 × 40 mm. As the CLAAS implant was compressed in the minor diameter, it increased in the major diameter, thereby filling the oval space, whereas the Watchman 2.5 showed gaps and maintained its round configuration when compressed in one direction. Seven devices were successfully implanted in the canine model with complete seal without thrombus. Histologic examination showed complete neointima covering with minimal inflammation at 60 days. CONCLUSIONS: Preclinical testing demonstrated the conformability of the CLAAS implant and its ability to seal the LAA. Clinical studies are ongoing to characterize the utility of the CLAAS implant in the treatment of patients with atrial fibrillation.

Preclinical comparative assessment of a dedicated pediatric poly-L-lactic-acid-based bioresorbable scaffold with a low-profile bare metal stent.

BACKGROUND: Polymer-based bioresorbable scaffolds (PBBS) have been assessed for coronary revascularization with mixed outcomes. Few studies have targeted pediatric-specific scaffolds. We sought to assess safety, efficacy, and short-term performance of a dedicated drug-free PBBS pediatric scaffold compared to a standard low-profile bare metal stent (BMS) in central and peripheral arteries of weaned piglets. METHODS: Forty-two devices (22 Elixir poly-L-lactic-acid-based pediatric bioresorbable scaffolds [BRS] [6 × 18 mm] and 20 control BMS Cook Formula 418 [6 × 20 mm]) were implanted in the descending aorta and pulmonary arteries (PAs) of 14 female Yucatan piglets. Quantitative measurements were collected on the day of device deployment and 30 and 90 days postimplantation to compare device patency and integrity. RESULTS: The BRS has a comparable safety profile to the BMS in the acute setting. Late lumen loss (LLL) and percent diameter stenosis (%DS) were not significantly different between BRS and BMS in the PA at 30 days. LLL and %DS were greater for BRS versus BMS in the aorta at 30 days postimplantation (LLL difference: 0.96 ± 0.26; %DS difference: 16.15 ± 4.51; p < .05). At 90 days, %DS in the aortic BRS was less, and PA BRS LLL was also less than BMS. Histomorphometric data showed greater intimal proliferation and area stenosis in the BRS at all time points and in all vessels. CONCLUSIONS: A dedicated PBBS pediatric BRS has a favorable safety profile in the acute/subacute setting and demonstrates characteristics that are consistent with adult BRSs.

The Market Reacts Quickly: Changes in Paclitaxel Vascular Device Purchasing Within the Ascension Healthcare System.

BACKGROUND: A meta-analysis of trials in endovascular therapy suggested an increased mortality associated with treatment exposure to paclitaxel. Multiple publications and corrections of prior data were performed, and the United States Food and Drug Administration has issued multiple advisories regarding paclitaxel use. We analyzed how this controversy impacted device purchasing and related utilization patterns in the period immediately following publication of the meta-analysis. METHODS AND RESULTS: Ascension Healthcare System purchase data over a 14-month period were synthesized across centers for both paclitaxel and non-paclitaxel devices. A fixed-effects regression model and a binary regression model with facility-level controls were used to compare purchasing patterns before and after the meta-analysis. Purchase volumes of each paclitaxel device fell. Pooled purchase volumes of all paclitaxel devices decreased from a 14-month peak of 631 devices in October 2018 to a 14-month nadir of 359 devices in February 2019. An F-test comparing the pooled-month specific fixed effects for the months before vs after the publication of the meta-analysis has an F-statistic of 11.64, suggesting that average purchasing levels in the two periods are statistically different (P<.001). Utilization of non-paclitaxel devices did not decline. CONCLUSIONS: Purchase volumes of paclitaxel devices decreased immediately during the months following publication of the related meta-analysis. Total Ascension-wide paclitaxel device purchase volume in February 2019 demonstrated a 43.1% reduction from peak monthly purchase volume during the assessed period and a 32.5% reduction compared with November 2019, the last month preceding publication of the meta-analysis.

Homologous and heterologous assessment of a novel biomaterial for venous patch.

OBJECTIVE: This study evaluated swine and bovine pulmonary visceral pleura (PVP) as a vascular patch. Venous patches are frequently used in surgery for repair or reconstruction of veins. Autologous patches are often limited by the number and dimension of donor tissue and can result in donor complications. Bovine pericardium is the most common heterologous patch used by vascular surgeons. Researchers, however, are continually seeking to improve heterologous and synthetic patches for improved outcome. METHODS: The PVP was peeled from swine and bovine lungs and cross-linked with glutaraldehyde. After sterilization and rinsing, the PVP patches were implanted in the jugular vein (10 × 35 mm) of pigs and dogs. Patency was evaluated by ultrasound, and animals were euthanized at 2 and 4 months. Neoendothelium and neomedia were evaluated by histologic analysis. RESULTS: The jugular vein patched by PVP in pigs and dogs remained patent at 2 and 4 months with no adhesions, inflammation, or aneurysm in the patches. The biomarkers of endothelial cells-factor VIII, platelet/endothelial cell adhesion molecule 1, and endothelial nitric oxide synthase-were detected in the neoendothelial cells. The expression of vascular smooth muscle cell (VSMC) α-actin was robust in the neomedia at 2 and 4 months. Neomedia composed of VSMCs developed to nearly double the thickness of adjacent jugular vein. The circumferential orientation of VSMCs in neomedia further increased in the 4-month group. CONCLUSIONS: The cross-linked swine and bovine PVP patch has a nonthrombogenic surface that maintains patency. The PVP patch may overcome the pitfall of compliance mismatch of synthetic patches. The proliferation of vascular cells assembled in the neoendothelium and neomedia in the patches may support long-term patency.

Post-stEnting assessment of Re-endothelialization with optical Frequency domain imaging aftEr Chronic Total Occlusion procedure: The PERFE-CTO Study Design and Rationale.

BACKGROUND: The treatment of chronic total occlusion of coronary arteries by percutaneous coronary intervention (CTO PCI) is one of the most representative technical advances in ischemic cardiomyopathy of last decade. However, how the complex histopathological remodeling and the new techniques affect healing processes after stent implantation remains unknown. OBJECTIVE: The objective of the PERFE-CTO study is to analyze stent coverage, malapposition and other mechanical abnormalities 3 months after CTO recanalization using intravascular imaging. METHODS: In a French prospective interventional multicenter study, stent strut coverage, acquired malapposition and neointimal hyperplasia (NIH) proliferation will be systematically assessed with 3 months angiogram control and intracoronary optical frequency domain imaging (OFDI) after successful CTO PCI of >20 mm in length. The impact of routine systematical intracoronary imaging after these complex procedures will also be evaluated by measuring the rate of significant mechanical abnormalities (strut malapposition, edge dissection, thrombus) that was undetected by fluoroscopy alone and by complementary PCI when needed. Secondarily, these data will be compared according to clinical characteristics, antiplatelet therapy use or desobstruction technique (antegrade vs. retrograde, true lumen vs. subintima). Each patient will undergo a one-year clinical follow-up. A total of 150 analyzed CTO lesions is expected. CONCLUSION: The PERFE-CTO study will provide essential understanding of the early history after CTO recanalization and the identification of inadequate evolution (stent thrombosis, restenosis or late delayed stent endothelization and cardiovascular outcomes) using intravascular imaging to improve long-term CTO results.

Assessment of Vascular Patency and Inflammation with Intravascular Optical Coherence Tomography in Patients with Superficial Femoral Artery Disease Treated with Zilver PTX Stents.

PURPOSE: Zilver PTX nitinol self-expanding drug-eluting stent with paclitaxel coating is effective for treatment of superficial femoral artery (SFA) disease. However, as with any stent, it induces a measure of vascular inflammatory response. The current clinical trial (NCT02734836) aimed to assess vascular patency, remodeling, and inflammatory markers with intravascular optical coherence tomography (OCT) in patients with SFA disease treated with Zilver PTX stents. METHODS: Serial OCT examinations were performed in 13 patients at baseline and 12-month follow-up. Variables evaluated included neointimal area, luminal narrowing, thrombus area, stent expansion as well as measures of inflammation including, peri-strut low-intensity area (PLIA), macrophage arc, neovascularization, stent strut apposition and coverage. RESULTS: Percentage of malapposed struts decreased from 10.3 ±â€¯7.9% post-intervention to 1.1 ±â€¯2.2% at 12-month follow-up, but one patient showed late-acquired stent malapposition (LASM). The percent of uncovered struts at follow-up was 3.0 ±â€¯4.5%. Average expansion of stent cross-sectional area from baseline to follow-up was 35 ±â€¯19%. The average neointimal area was 7.8 ±â€¯3.8 mm2. Maximal luminal narrowing was 61.1 ±â€¯25.0%, and average luminal narrowing was 35.4 ±â€¯18.2%. Average peri-strut low-intensity area (PLIA) per strut was 0.017 ±â€¯0.018 mm2. Average number of neovessels per mm of stent was 0.138 ±â€¯0.181. Average macrophage angle per frame at follow-up was 7 ±â€¯11°. Average thrombus area at follow-up was 0.0093 ±â€¯0.0184 mm2. CONCLUSION: At 12-month follow-up, OCT analysis of Zilver PTX stent shows outward remodeling and minimal neointimal growth, but evidence of inflammation including PLIA, neovessels, thrombus and macrophages. SUMMARY: Thirteen patients with PAD had paclitaxel-coated stents implanted in their SFAs and were then imaged with OCT at baseline and 12-month follow-up. OCT proxy metrics of inflammation were quantified.

Assessment of residual thrombus burden in patients with ST-segment elevation myocardial infarction undergoing bivalirudin versus unfractionated heparin infusion: The MATRIX (minimizing adverse hemorrhagic events by transradial access site and angioX) OCT study.

BACKGROUND: Residual stent strut thrombosis after primary percutaneous coronary intervention (PCI), negatively affects myocardial perfusion, may increase stent thrombosis risk, and it is associated with neointima hyperplasia at follow-up. OBJECTIVES: To study the effectiveness of any bivalirudin infusion versus unfractionated heparin (UFH) infusion in reducing residual stent strut thrombosis in patients with ST-elevation myocardial infarction (STEMI). METHODS: Multi-vessel STEMI patients undergoing primary PCI and requiring staged intervention were selected among those randomly allocated to two different bivalirudin infusion regimens in the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) Treatment-Duration study. Those receiving heparin only were enrolled into a registry arm. Optical coherence tomography (OCT) of the infarct-related artery was performed at the end of primary PCI and 3-5 days thereafter during a staged intervention. The primary endpoint was the change in minimum flow area (ΔMinFA) defined as (stent area + incomplete stent apposition [ISA] area) - (intraluminal defect + tissue prolapsed area) between the index and staged PCI. RESULTS: 123 patients in bivalirudin arm and 28 patients in the UFH arm were included. Mean stent area, percentage of malapposed struts, and mean percent thrombotic area were comparable after index or staged PCI. The ΔMinFA in the bivalirudin group was 0.25 versus 0.05 mm2 in the UFH group, which resulted in a between-group significant difference of 0.36 [95% CI: (0.05, 0.71); p = .02]. This was mostly related to a decrease in tissue protrusion in the bivalirudin group (p = .03). There was a trend towards more patients in the bivalirudin group who achieved a 5% difference in the percentage of OCT frames with the area >5% (p = .057). CONCLUSIONS: The administration of bivalirudin after primary PCI significantly reduces residual stent strut thrombosis when compared to UFH. This observation should be considered hypothesis-generating since the heparin-treated patients were not randomly allocated.

Treatment of In-Stent Restenosis by Excimer Laser Coronary Atherectomy and Drug-Coated Balloon: Serial Assessment with Optical Coherence Tomography.

OBJECTIVES: We aimed to compare the results of neointimal modification before drug-coated balloon (DCB) treatment with excimer laser coronary atherectomy (ELCA) plus scoring balloon predilation versus scoring balloon alone in patients presenting with in-stent restenosis (ISR). BACKGROUND: Treatment of ISR with ELCA typically results in superior acute gain by neointima debulking. However, the efficacy of combination therapy of ELCA and DCB remains unknown. METHODS: A total of 42 patients (44 ISR lesions) undergoing DCB treatment with ELCA plus scoring balloon (ELCA group, n = 18) or scoring balloon alone (non-ELCA group, n = 24) were evaluated via serial assessment by optical coherence tomography (OCT) performed before, after intervention, and at 6 months. RESULTS: Although there was significantly greater frequency of diffuse restenosis and percent diameter stenosis (%DS) after intervention in the ELCA group, comparable result was shown in %DS, late lumen loss, and binary angiographic restenosis at follow-up. On OCT analysis, a decreased tendency in the minimum lumen area and a significant decrease in the minimum stent area were observed in the ELCA group between 6-month follow-up and after intervention (-0.89 ± 1.36 mm2 vs. -0.09 ± 1.25 mm2, p = 0.05, -0.49 ± 1.48 mm2 vs. 0.28 ± 0.78 mm2, p = 0.03, respectively). The changes in the neointimal area were similar between the groups, and target lesion revascularization showed comparable rates at 1 year (11.1% vs. 11.4%, p = 0.85). CONCLUSIONS: Despite greater %DS after intervention, ELCA before DCB had possible benefit for late angiographic and clinical outcome.

Assessment of strut coverage of everolimus-eluting platinum chromium stent 2 weeks after implantation by optical coherence tomography.

The SYNERGY coronary stent is new-generation drug-eluting stents, which has a thin-strut platinum-chromium platform with everolimus in a biodegradable polymer applied to the abluminal surface. It would be speculated that favorable arterial healing with early strut coverage could be achieved. The present study investigated the degree of strut coverage using optical coherence tomography (OCT) 2 weeks after SYNERGY implantation and clinical factors contributing to strut coverage. A total of 29 patients who underwent staged percutaneous coronary intervention (PCI) to residual lesions 2 weeks after the index PCI with SYNERGY stent implantation were enrolled. At the time of staged PCI, OCT examinations of the SYNERGY stent were performed for conventional OCT analysis on both cross-sectional and strut level. SYNERGY stent showed a high level of strut coverage and apposition, and the percentage was 82.4 ± 12.4% and 96.2 ± 5.0%, respectively. The lesion complexity was significantly related to greater strut coverage on univariate analysis; however, it was found to be insignificant in multivariate analysis. Our findings suggest early arterial healing after SYNERGY stent implantation.

A novel endovenous scaffold for the treatment of chronic venous obstruction in a porcine model: Histological and ultrastructural assessment.

OBJECTIVE: To investigate the biological effects of a novel endovenous scaffold in a porcine model. METHODS: Petalo is a compliant venous scaffold implanted into the internal jugular veins of 12 healthy pigs. The pigs were sacrificed at one, two, three, and six months, respectively. Microscopic investigations were performed at two blinded laboratories. RESULTS: Neo-intima formation progressively covering up the stent metallic bars was observed. The inflammatory response of the venous wall showed a peak after three months by the implant, followed by marked reduction after six months. The device induced a significant ( p < 0.01) increase of the thickness respect to the control regions, but was comparable in sections obtained after three and six months. CONCLUSIONS: The implant of Petalo compliant venous scaffold in the venous wall of this porcine model is characterized by neointima formation and by an inflammatory reaction which tends to decrease after six months. Our data point against the induction of smooth muscle cells proliferation and migration as confirmed by electronic transmission microscopy analyses.

A serial 3- and 9-year optical coherence tomography assessment of vascular healing response to sirolimus- and paclitaxel-eluting stents.

Early-generation drug-eluting stents (DES) have been demonstrated to delay vascular healing. Limited optical coherence tomography (OCT) data on the very long-term neointimal response after DES implantation are available. The aim of this study was a serial OCT assessment of neointimal thickness, stent strut coverage, malapposition, and protrusion as markers of neointimal response at 3 and 9 years after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES). In this single-centre, longitudinal study consecutive patients undergoing elective PCI with SES or PES were included. OCT analysis was performed after 3 and 9 years by the independent core laboratory. A total of 22 subjects (8 SES and 14 PES) underwent an OCT assessment at 3 and 9 years post index procedure. The lumen, neointimal and malapposition area and the neointimal thickness (SES ∆50 µm, p = 0.195, PES ∆10 µm, p = 0.951) did not change significantly over the 6 year follow-up. No differences in the incidence of uncovered, malapposed or protruding struts were found in each type of stent. At 3 and 9 years after PCI, implantation of early-generation SES and PES may be associated with similar neointimal thickness, strut coverage, malapposition and protrusion, as assessed by serial OCT examination among patients with uneventful follow-up at 3 years post procedure. The small size of the study warrants judicious interpretation of our results and confirmation in larger multimodality imaging studies, including patients treated with contemporary stent platforms.

Uncertainty Quantification of a Multiscale Model for In-Stent Restenosis.

PURPOSE: Coronary artery stenosis, or abnormal narrowing, is a widespread and potentially fatal cardiac disease. After treatment by balloon angioplasty and stenting, restenosis may occur inside the stent due to excessive neointima formation. Simulations of in-stent restenosis can provide new insight into this process. However, uncertainties due to variability in patient-specific parameters must be taken into account. METHODS: We performed an uncertainty quantification (UQ) study on a complex two-dimensional in-stent restenosis model. We used a quasi-Monte Carlo method for UQ of the neointimal area, and the Sobol sensitivity analysis (SA) to estimate the proportions of aleatory and epistemic uncertainties and to determine the most important input parameters. RESULTS: We observe approximately 30% uncertainty in the mean neointimal area as simulated by the model. Depending on whether a fast initial endothelium recovery occurs, the proportion of the model variance due to natural variability ranges from 15 to 35%. The endothelium regeneration time is identified as the most influential model parameter. CONCLUSION: The model output contains a moderate quantity of uncertainty, and the model precision can be increased by obtaining a more certain value on the endothelium regeneration time. We conclude that the quasi-Monte Carlo UQ and the Sobol SA are reliable methods for estimating uncertainties in the response of complicated multiscale cardiovascular models.

Assessment of Second- and Third-Generation Drug-Eluting Stents on Chronic Coronary Angioscopy　- Multicenter Study on Intra-Coronary AngioScopy After Stent (MICASA) Prospective Data Analysis.

BACKGROUND: The vascular response, in terms of quality and quantity, of the second- and third-generation drug-eluting stents (2G- and 3G-DES, respectively) was assessed prospectively on coronary angioscopy (CAS).Methods and Results:The Multicenter study on Intra-Coronary AngioScopy After Stent (MICASA) is a multicenter CAS registry. A total of 107 DES (71 2G- and 36 3G-DES) were prospectively observed on CAS 8.7±2.7 months after percutaneous coronary intervention. Neointimal coverage (NC) grade was evaluated using a 4-point grading scale, from 0 (no coverage) to 3 (complete coverage). Plaque yellow color (YC) was also assessed using a 4-point grading system, from 0 (white) to 3 (bright yellow). Max-NC (2G-DES vs. 3G-DES: 2.14±0.68 vs. 2.44±0.73, P=0.023); min-NC (1.07±0.48 vs. 1.39±0.60, P=0.002), and dominant-NC (1.57±0.69 vs. 2.08±0.84, P=0.002) were significantly higher and the YC grade (1.23±0.82 vs. 0.86±0.76, P=0.031) significantly lower in the 3G-DES group than in the 2G-DES group. There was no significant difference in the presence of thrombus (28.2% vs. 22.2%, P=0.51) between the 2G- and 3G-DES groups. CONCLUSIONS: The higher NC grade and lower YC grade in 3G-DES than in 2G-DES might be associated with better long-term clinical outcome, which remains to be determined in future studies.

Comparative assessment of three drug eluting stents with different platforms but with the same biodegradable polymer and the drug based on quantitative coronary angiography and optical coherence tomography at 12-month follow-up.

The aim of this study was to compare neointima proliferation in three drug-eluting stents (DES) produced by the same company (Balton, Poland) which are covered with a biodegradable polymer and elute sirolimus (concentration: 1.0 and 1.2 µg/mm2), but have different stent platforms and strut thickness: stainless steel Prolim® (115 µm) and BiOSS LIM® (120 µm) and cobalt-chromium Alex® (70 µm). We analyzed data of patients with quantitative coronary angiography (QCA) and optical coherence tomography (OCT) at 12 months from BiOSS LIM Registry, Prolim Registry and Alex OCT clinical trial. There were 56 patients enrolled, in whom 29 Prolim® stents were deployed, in 11-BiOSS LIM® and in 16-Alex stents. The late lumen loss was the smallest in Prolim® subgroup (0.26 ± 0.17 mm) and did not differ from Alex® subgroup (0.28 ± 0.47 mm). This parameter was significantly bigger in BiOSS® subgroup (0.38 ± 0.19 mm; p < 0.05). In OCT analysis there was no statistically significant difference between Prolim® and Alex® subgroups in terms of mean neointima burden (24.6 ± 8.6 vs. 19.27 ± 8.11%) and neointima volume (28.16 ± 15.10 vs. 24.51 ± 17.64 mm3). In BiOSS® group mean neointima burden (30.9 ± 6.2%) and mean neointima volume (44.9 ± 4.9 mm3) were significantly larger. The morphological analysis revealed that in most cases in all groups the neointima was homogenous with plaque presence only around stent struts. In the QCA and OCT analysis regular DES (Prolim® and Alex®) obtained similar results, whereas more pronounced response from the vessel wall was found in the BiOSS® subgroup.

First serial optical coherence tomography assessment at baseline, 12 and 24 months in STEMI patients treated with the second-generation Absorb bioresorbable vascular scaffold.

AIMS: The aim of the study was to assess the vascular healing response after Absorb bioresorbable vascular scaffold (BVS) implantation in patients with ST-segment elevation myocardial infarction (STEMI) utilising truly serial optical coherence tomography (OCT) examination at baseline, 12 and 24 months. METHODS AND RESULTS: This was a single-centre, prospective, longitudinal study with baseline, 12- and 24-month OCT evaluation of 18 STEMI patients treated with 22 Absorb BVS. The healing pattern was evaluated based upon lumen area, neointimal hyperplasia, strut coverage and apposition. The lumen area decreased at 12 months compared to baseline (8.52±1.69 mm² vs. 7.0±1.70 mm², p<0.01), but it did not change from that point onwards up to 24 months (7.0±1.70 mm² vs. 6.94±1.65 mm², p=0.92). At 12 months after the index procedure, the mean neointimal thickness was 217±69 µm and further neointimal hyperplasia was observed between 12 and 24 months though less pronounced (Δ62±44 µm, p<0.0001). Full circumferential coverage of the vessel wall by neointima was observed in 92% of frames at 24 months. The low number of malapposed struts at the index procedure (<5%) further decreased over the observation period and was found in only one patient at 12 and 24 months. The ratio of uncovered struts was low at both 12 and 24 months. CONCLUSIONS: This serial OCT analysis of the second-generation everolimus-eluting BVS in a STEMI population confirmed a favourable healing pattern as expressed by moderate neointimal growth, preserved lumen area and no late acquired malapposition.

Serial Assessment of Strut Coverage of Biodegradable Polymer Drug-Eluting Stent at 1, 2, and 3 Months After Stent Implantation by Optical Frequency Domain Imaging: The DISCOVERY 1TO3 Study (Evaluation With OFDI of Strut Coverage of Terumo New Drug Eluting Stent With Biodegradable Polymer at 1, 2, and 3 Months).

BACKGROUND: To assess the vessel-healing pattern of Ultimaster drug-eluting stent using optical frequency domain imaging. Our hypothesis is that biodegradable polymer-based drug-eluting technology allows complete very early strut coverage. METHODS AND RESULTS: The DISCOVERY 1TO3 study (Evaluation With OFDI of Strut Coverage of Terumo New Drug Eluting Stent With Biodegradable Polymer at 1, 2, and 3 Months) is a prospective, single-arm, multicenter study. A total of 60 patients with multivessel disease requiring staged procedure at 1 month were treated with Ultimaster. Optical frequency domain imaging was acquired at baseline, 1, 2, and 3 months. The primary end point is optical frequency domain imaging-assessed strut coverage at 3 months. Mean age of patients was 67.2±9.9 years, and 73.3% were male, and 36.7% presented with acute coronary syndrome. A total of 132 lesions were treated, with average 1.4 lesions per patient treated at baseline and 1.1 lesions treated at 1 month. Strut coverage at 3 months of single implanted stents (n=71, primary end point) was 95.2±5.2% and of combined single and overlapped stents was 95.4±4.9%. Strut coverage of combined single and overlapped stents at 1 (n=49) and 2 months (n=38) was 85.1±12.7% and 87.9±10.8%, respectively. The median neointimal hyperplasia thickness was 0.04, 0.05, and 0.06 mm, whereas mean neointimal hyperplasia obstruction was 4.5±2.4%, 5.2±3.4%, and 6.6±3.3% at 1, 2, and 3 months, respectively. CONCLUSIONS: Nearly complete strut coverage was observed in this complex population very early after implantation of Ultimaster drug-eluting stent. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01844843.

Abluminal Neointimal Healing by Optical Coherence Tomography Assessment After Drug-Eluting Stent Implantation on Organized Recanalized Thrombus.

Six-month PCI follow-up results of left anterior descending (LAD) and circumflex (CX) drug-eluting stent implantation are presented. Angiography showed patent LAD and CX stents. However, OCT revealed almost all abluminal cavities were completely filled, which the authors surmise was due to a neointimal healing process.