Peri-strut Low-intensity Area Research Articles

Temporal course of vascular response after fluoropolymer paclitaxel-eluting stent implantation for femoropopliteal artery lesions

Abstract Background Limited data is available regarding the vascular response after fluoropolymer paclitaxel-eluting stent (FP-PES) implantation. We sought to assess the vascular response at 6- and 12-month after FP-PES implantation for femoropopliteal artery lesions using serial optical coherence tomography (OCT) examination. Methods and results From the IMPERIAL trial, this study evaluated 10 de novo femoropopliteal lesions treated with FP-PES. The primary study endpoint was neointimal tissue coverage at 6- and 12-month follow-up as assessed by serial OCT examination. The incidence of peri-strut low-intensity area (PLIA) and extra-stent lumen (ESL) was also assessed. A total of 203 matched cross-sectional images were evaluated at 6- and 12-month (5,615 and 5,763 struts, respectively). From 6 to 12 months, the mean neointimal thickness tended to increase from 198 μm to 233 μm with a significant reduction in the incidence of malapposed struts (0.59% vs. 0.28%, p=0.039). Conversely, uncovered struts and PLIA were more frequently observed at 12 months (4.4% vs. 7.8%, p=0.01; 12.7% vs. 21.0%, p<0.001, respectively). The ESL area significantly increased over time without any difference in its incidence (0.24±0.32 mm2 vs. 0.38±0.36 mm2, p=0.009). Conclusions Neointimal proliferation was markedly inhibited from 6 to 12 months after FP-PES implantation, whereas the incidence of uncovered struts and PLIA significantly increased over time with the enlargement of ESL. Funding Acknowledgement Type of funding sources: None.

A serial optical frequency-domain imaging study of early and late vascular responses to bioresorbable-polymer sirolimus-eluting stents for the treatment of acute myocardial infarction and stable coronary artery disease patients: results of the MECHANISM-ULTIMASTER study

The purpose of this study was to assess early and late vascular healing in response to bioresorbable-polymer sirolimus-eluting stents (BP-SESs) for the treatment of patients with ST-elevation myocardial infarction (STEMI) and stable coronary artery disease (CAD). A total of 106 patients with STEMI and 101 patients with stable-CAD were enrolled. Optical frequency-domain images were acquired at baseline, at 1- or 3-month follow-up, and at 12-month follow-up. In the STEMI and CAD cohorts, the percentage of uncovered struts (%US) was significantly and remarkably decreased during early two points and at 12-month (the STEMI cohort: 1-month: 18.75 ± 0.78%, 3-month: 10.19 ± 0.77%, 12-month: 1.80 ± 0.72%; p < 0.001, the CAD cohort: 1-month: 9.44 ± 0.78%, 3-month: 7.78 ± 0.78%, 12-month: 1.07 ± 0.73%; p < 0.001 respectively). The average peri-strut low-intensity area (PLIA) score in the STEMI cohort was significantly decreased during follow-up period (1.90 ± 1.14, 1.18 ± 1.25, and 1.01 ± 0.72; p ≤ 0.001), whereas the one in the CAD cohort was not significantly changed (0.89 ± 1.24, 0.67 ± 1.07, and 0.64 ± 0.72; p = 0.59). In comparison with both groups, differences of %US and PLIA score at early two points were almost disappeared or close at 12 months. The strut-coverage and healing processes in the early phase after BP-SES implantation were significantly improved in both cohorts, especially markedly in STEMI patients. At 1 year, qualitatively and quantitatively consistent neointimal coverage was achieved in both pathogenetic groups.

Comparison of post-stent irregular protrusion and subsequent neointimal characteristics between second- and third-generation drug-eluting stent implantation

BackgroundThird-generation drug-eluting-stents (3rd DES) may improve coronary arterial healing and reduce neoatherosclerosis formation. We evaluated post-stent findings and subsequent vascular healing of 3rd DES by comparing to second-generation drug-eluting-stents (2nd DES) at intermediate-term follow-up using optical coherence tomography (OCT). MethodWe evaluated 170 patients with 170 lesions who underwent DES implantation (2nd DES, n = 98; 3rd DES, n = 72) and OCT-guided follow-up examination. After propensity score (PS) matching for baseline clinical characteristics, OCT findings from 56 pairs of patients with 2nd DES and 3rd DES implants were compared. Post-stent irregular protrusion (IP) was defined as the protrusion of material with an irregular surface into the lumen between the stent struts. Neoatheroscleosis was defined as neointima contained heterogeneous pattern, rupture, lipid-laden, thin-cap fibroatheroma, or calcification. The presence of peri-strut low-intensity area (PLIA) and in-stent neointimal tissue characteristics were also analyzed at 6- to 8-month follow-up. ResultsThere were no significant differences between the incidence of post-stent IP or neoatherosclerosis formation in the 2nd DES and the 3rd DES (45% vs. 38%, p = 0.44; 30% vs. 20%, p = 0.19, respectively). However, the incidences of PLIA and layered neointimal pattern, which indicate immature neointimal healing, were significantly lower in the 3rd DES compared to the 2nd DES (41% vs. 61%, p = 0.04; 2% vs. 11%, p = 0.04, respectively). As comparing intermediate-term follow-up OCT neointimal findings in patients with IP between 2nd DES and 3rd DES, most neointima tended to have a homogeneous pattern (95% versus 76%, p = 0.06) in the 3rd DES than in the 2nd DES. ConclusionsThe incidence of post-stent IP and subsequent neoatherosclerosis formation at intermediate-term follow-up after stent implantation were similar between patients with 2nd DES and 3rd DES, however, vascular healing might be favorable when using 3rd DES.

Peri-strut low intensity areas and in-scaffold neointima growth after bioresorbable scaffold implantation in STEMI. A serial optical coherence tomography study

BackgroundPeri-strut low intensity areas (PLIA) visualized by optical coherence tomography (OCT) have been related to neointimal proliferation and increased incidence of target lesion revascularization in stable coronary artery disease. The aim of this study was to determine the association between PLIA by OCT and the long-term vascular healing response after bioresorbable scaffold (BRS) implantation in the setting of ST-segment elevation myocardial infarction (STEMI). MethodsThis is a single-centre, longitudinal, cohort study with a serial: baseline, 1, 2 and 5 years OCT evaluation of neointimal response (lumen area and neoatherosclerosis) after percutaneous coronary intervention (PCI) with BRS Absorb™ 1.0 implantation in patients presenting with STEMI. PLIA was analyzed in every cross section and scored: 0–no PLIA; 1-PLIA < 1 quadrant; 2-PLIA ≥ 1 and <2 quadrants; 3-PLIA ≥ 2 and <3 quadrants; 4-PLIA in ≥3 quadrants. ResultsOf the 23 patients implanted BRS, 18 completed 2-year follow-up, whereas complete OCT data up to 5 years were available in 12 patients. Presence of PLIA was identified in 100% patients at 1 and 2 years, whereas at 5 years neither PLIA nor scaffold struts were visualized by OCT. Neoatherosclerosis was identified in 73,68% patients after 1 year and in all patients at 2 and 5 years. The mean PLIA score > 1 at 2 years was associated with greater percentage of minimum lumen area decrease after 2 years from index procedure. ConclusionsThe extent of PLIA by OCT at 2 years after primary PCI with BRS was associated with lumen area decrease. Neoatherosclerosis formation was detected in all patients at 2 and 5 years. PLIA assessment could serve as an additive means to predict neointimal healing pattern after next generation BRS implantation.

A case report of a recurrent early and late Bioresorbable vascular scaffold thrombosis: serial angiography and optical coherence tomography findings

BackgroundIn bioresorbable vascular scaffolds (BVSs), there is some concern about a possible increase in the rate of scaffold thromboses (ScTs). Although several characteristics similarly contribute to the development of both early and late ScTs, there are also clearly different pathomechanisms between the two time-dependent types of thromboses, especially with BVSs.Case presentationWe recently experienced a very rare case of a 69-year-old man who had recurrent early and late ScTs with somewhat differing pathomechanisms as assessed by optical coherence tomography (OCT). For the late ScT, OCT identified a scaffold dismantling in the same place that a peri-strut low intensity area (PLIA) was observed in the previous OCT finding.ConclusionWe report the management of an ScT in a case with findings such as a heterogeneous a BVS degradation, peri-strut low intensity area (PLIA), intraluminal scaffold dismantling, and under-sizing and/or stent malapposition observed in OCT.

TCT-182 Peristrut Low-Intensity Areas and Neointimal Response Evaluation by Serial Optical Coherence Tomography at Baseline and 1, 2, and 5 Years After Bioresorbable Scaffold Implantation in STEMI

Peristrut low-intensity areas (PLIA) surrounding metallic stent struts, visualized by optical coherence tomography (OCT), have been recently linked to inflammation, neointimal proliferation, and increased incidence of target lesion revascularization. In-scaffold neoatherosclerosis with luminal

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

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. 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. Percentage of malapposed struts decreased from 10.3 ± 7.9% post-intervention to 1.1 ± 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 ± 4.5%. Average expansion of stent cross-sectional area from baseline to follow-up was 35 ± 19%. The average neointimal area was 7.8 ± 3.8 mm2. Maximal luminal narrowing was 61.1 ± 25.0%, and average luminal narrowing was 35.4 ± 18.2%. Average peri-strut low-intensity area (PLIA) per strut was 0.017 ± 0.018 mm2. Average number of neovessels per mm of stent was 0.138 ± 0.181. Average macrophage angle per frame at follow-up was 7 ± 11°. Average thrombus area at follow-up was 0.0093 ± 0.0184 mm2. 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. 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.

Peri-strut low-intensity area assessed by midterm follow-up optical coherence tomography may predict target lesion revascularisation after everolimus-eluting stent implantation

Peri-strut low-intensity area (PLIA) assessed by optical coherence tomography (OCT) has been reported as a potential marker of abnormal neointimal healing. We aimed to evaluate the impact of PLIA on clinical events and its risk factors. We enrolled 264 consecutive patients treated with an everolimus-eluting stent (EES) who underwent follow-up OCT six to 12 months after stenting. Target lesion revascularisation (TLR) was evaluated at a mean 42.6 months after stenting. PLIA was identified in 102 patients; 162 patients did not exhibit PLIA. Multivariate Cox hazard regression analysis indicated that the presence of PLIA (PLIA+) was an independent risk factor for an increased incidence of TLR (hazard ratio [HR]: 4.608, p=0.003). In both the early (<1 year) and late (>1 year) phases, the incidence of TLR was significantly higher in the PLIA+ group (p<0.001 and p<0.001, respectively). In the Cox hazard regression analysis, current smoking and increased C-reactive protein level were independently associated with PLIA+ (HR: 1.737, p=0.009; HR: 2.435, p=0.008, respectively). The presence of PLIA on midterm OCT was associated with TLR after EES implantation. Detailed stent assessment by midterm OCT may help to predict stent failure in patients treated with EES.

The comparison of early healing 1-month after PCI among CoCr-everolimus-eluting stent (EES), biodegradable polymer (BP)-EES and BP-sirolimus-eluting stent: Insights from OFDI and coronary angioscopy

BackgroundThird-generation stents with abluminal biodegradable polymer (BP) might facilitate early healing. Therefore, we compared early healing between second-generation and third-generation stents using coronary angioscopy (CAS) and optical frequency domain imaging [OFDI]. MethodsWe prospectively enrolled 30 consecutive patients with stent implantation for acute coronary syndrome (cobalt‑chromium [CoCr] everolimus-eluting stent [EES] [n = 10], BP-EES [n = 10], and BP-sirolimus eluting stent [SES] [n = 10]). All patients underwent CAS and OFDI 1 month after initial percutaneous coronary intervention. On OFDI, the stent coverage (SC), thrombus, and peri-strut low intensity area (PLIA) were assessed. CAS findings were recorded for the grade of SC, grade of yellow color (YC), and grade of the thrombus (TG). ResultsOn OFDI, the incidences of any thrombus at the 1-month follow-up were 70%, 80%, and 80% in the CoCr-EES, BP-EES, and BP-SES groups, respectively. The percentage of coverage was comparable among the groups (CoCr-EES 79.8 vs. BP-EES 79.9 vs. BP-SES 80.1%, P = 0.96). However, the number of struts with PLIA was numerically higher in the BP-SES group than in the CoCr-EES and BP-EES groups (46.4 ± 25.1 vs. 21.6 ± 13.2 vs. 22.0 ± 7.2%, P = 0.08). In the CoCr-EES, BP-EES, and BP-SES groups, mean grades of SC were 1.25 ± 0.5, 1.25 ± 0.5, and 0.85 ± 0.70 (P = 0.60); mean grades of YC were 0.75 ± 0.5, 0.80 ± 0.45, and 0.88 ± 0.37 (P = 0.65), and mean grades of TG were 1.00 ± 1.00, 1.20 ± 0.83, and 0.88 ± 0.64 (P = 0.75), respectively. ConclusionThird-generation stents are not inferior to second-generation stents regarding stent coverage. However, PLIA on OFDI was often observed with BP-SESs, indicating involvement of the fibrin component.

Favorable early vessel healing after everolimus-eluting stent implantation: 3-, 6-, and 12-month follow-up of optical coherence tomography

BackgroundAlthough a prospective randomized control study revealed that 3-month dual anti-platelet therapy (DAPT) is safe and does not compromise the efficacy of everolimus-eluting stent (EES) in selected patients, detailed vessel healing at early phase after EES implantation has yet to be investigated in Japanese patients. Methods and resultsA total of 27 lesions in 19 patients treated with EES were serially evaluated by using optical coherence tomography (OCT) at 3, 6, and 12 months after stent implantation. In addition to standard quantitative OCT parameters, the percentage of stents with peri-strut low-intensity area (PLIA, a region around stent struts homogenously showing lesser intensity than the surrounding tissue, suggesting fibrin deposition or impaired neointima maturation) and that with in-stent thrombi were evaluated.There was a significant, but small increase in neointimal thickness (63±17μm; 83±30μm; and 111±44μm, respectively; p=0.006) and small decrease in average lumen area (6.80±2.57mm2, 6.62±2.58mm2, 6.33±2.58mm2, p=0.038) from the 3- to the 12-month follow-up. The incidences of uncovered and malapposed struts were low at 3 months and did not significantly change at 6 months and 12 months (3.01±4.43; 2.45±3.75; and 1.47±3.16, p=0.143, and 0.75±0.65; 0.63±0.73; and 0.58±1.42, p=0.162, respectively). Also, frequency of struts with PLIA was already low at three months and significantly decreased during the follow-up (6.4±6.5; 4.6±5.4; and 2.3±3.3, respectively; p=0.001). ConclusionFavorable vessel healing was achieved at 3 months after EES implantation without neointimal hyperplasia which was persistently suppressed up to 12 months.

Relationship between peri-strut low intensity areas and vascular healing response after everolimus-eluting bioresorbable scaffold implantation: An optical coherence tomography study

BackgroundPeri-strut low intensity areas (PLIA) surrounding metallic coronary stent struts on optical coherence tomography (OCT) images have been histologically related to delayed healing and inflammation, and have been associated with neointimal proliferation. The relationship between PLIA and vascular healing response after bioresorbable scaffold (BRS) implantation remains unclear. MethodsThis study includes 38 consecutive patients (50 scaffolds) evaluated using OCT 12 months after BRS implantation. Mean and percent neointimal area were quantified. A PLIA was defined as a peri-strut region with an homogenous lower intensity appearance than the surrounding tissue on OCT images without significant signal attenuation. Cross sections were scored as follows: score 0, no PLIA; score 1, <1 quadrant; score 2, ≥1 but <2 quadrants; score 3, ≥2 quadrants but <3 quadrants; and score 4, ≥3 quadrants. Scaffolds were divided into two groups (PLIA+ and PLIA−) based on the presence or absence of any PLIA in the scaffold segment. ResultsThe frequency of any PLIA within the scaffold segment was 70.0%. The median PLIA score per scaffold was 0.51 (interquartile range 0–1.07). Using both scaffold- and frame-level analysis, a significant positive correlation was observed between PLIA score and both mean and percent neointimal area. Mean and percent neointimal area were significantly higher in the PLIA+ group than in the PLIA− group (1.95±0.65mm2 vs. 1.51±0.27mm2, p<0.01 and 24.0±7.0% vs. 17.4±3.6%, p<0.01, respectively). ConclusionThe presence and extent of PLIA on OCT imaging after BRS implantation appears to be significantly associated with neointimal formation.

ASSESSMENT OF PERI-STRUT LOW INTENSITY AREAS IDENTIFIED BY OPTICAL COHERENCE TOMOGRAPHY AFTER STENT IMPLANTATION: AN EX VIVO HISTOLOGICAL VALIDATION STUDY

The histology of peri-strut low intensity areas (PLIA) identified by optical coherence tomography (OCT) is still not well assessed by human autopsy. A total of 15 stents (7 bare-metal stents; BMS, 8 drug-eluting stents; DES) implanted human coronary artery were collected from 5 cadavers. The

Clinical Characteristics and Prognosis of Peri-strut Low-intensity Area Detected by Optical Coherence Tomography.

Background:Peri-strut low-intensity area (PLIA) is a typical image pattern of neointima detected by optical coherence tomography (OCT) after stent implantation. However, few studies evaluated the predictors and prognosis of the PLIA; therefore, we aimed to explore the genesis and prognosis of PLIA detected by OCT in this study.Methods:Patients presenting neointimal hyperplasia documented by OCT reexamination after percutaneous coronary intervention were prospectively included from 2009 to 2011. Peri-strut intensity was analyzed and classified into two patterns: Low-intensity and high-intensity. Clinical characteristics were analyzed to assess their contribution to peri-strut intensity patterns. Follow-up were performed in patients who did not receive revascularization during OCT reexamination, and the prognosis of the patients was evaluated.Results:There were 128 patients underwent OCT reexamination after stent implantation included in the study. PLIA was detected in 22 (17.2%) patients. The incidence of PLIA was positively correlated with serum triglyceride (odds ratio [OR]: 2.11, 95% confidence interval [CI]: 1.14–3.90, P = 0.017), low-density lipoprotein (OR: 2.61, 95% CI: 1.22–5.66, P = 0.015), history of cerebrovascular disease (OR: 101.11, 95% CI: 6.54–1562.13, P < 0.001), and initial clinical presentation of acute coronary syndrome (ACS, OR: 18.77, 95% CI: 2.73–128.83, P = 0.003) while negatively correlated with stent implantation time (OR: 0.57, 95% CI: 0.33–0.98, P = 0.043). The median follow-up was longer than 3.8 years. Major adverse cardiovascular events (MACEs) occurred in 7 (7.3%) patients while showed no correlation with PLIA. A total of 17 (17.7%) patients experienced unstable angina (UA) and showed significant correlation with PLIA (hazard ratio: 6.16, 95% CI: 1.25–30.33, P = 0.025).Conclusions:PLIA detected by OCT was positively correlated with higher serum lipid level, history of cerebrovascular disease and initial presentation of ACS, and negatively correlated with stent implantation time. Patients with PLIA were more likely to have UA than those with high-intensity while no significant difference was found in MACEs.

Abstract 14342: Relationship Between Peri-Strut Low Intensity Areas and Vascular Healing Response After Everolimus-Eluting Bioresorbable Scaffold Implantation: an Optical Coherence Tomography Study

Objects: Peri-strut low intensity areas (PLIA) surrounding stent struts on optical coherence tomography (OCT) images has been histologically related to the delayed healing and inflammation, and have been previously associated with neointimal proliferation particularly in first generation drug-eluting stent era. However, the relationship between PLIA and bioresorbable vascular scaffolds (BRS) implantation remains to be clarified. Methods: Of 149 patients treated with the everolimus-eluting BRS at a single institution and followed-up for at least 6 months, 38 patients (50 lesions) underwent follow-up coronary angiography including OCT 11.0 ± 2.1 months after BRS implantation. All patients were prescribed lifelong aspirin (100mg/d) and prasugrel (10mg/d) for at least 6 months. The mean- and percent- neointimal area were evaluated by OCT. PLIA was defined as a peri-strut region with a homogenous lower intensity appearance than the surrounding tissue on OCT images without significant signal attenuation and was graded as follows:grade 0, no PLIA; grade 1, &lt;1 quadrant; grade 2, ≥1 but &lt;2 quadrants; grade 3, ≥2 quadrants but &lt;3 quadrants; and grade 4, ≥ 3 quadrants. Additionally, all patients were divided into two groups (PLIA+ group, N=35 and PLIA- group,N=15). Results: The frequency of any PLIA within the scaffold segment was 70.0% (35/50 scaffolds). Mean PLIA grade score was 0.72± 0.77 [Median value (interquartile range), 0.51 (0, 1.07)]. There were significant positive correlations between PLIA score and both mean- (R=0.55,p&lt;0.01) and percent- neointimal area (R=0.58,p&lt;0.01). Both mean- and percent- neointimal area were significantly higher in the PLIA+ group than in the PLIA- group (1.95±0.65 vs. 1.51±0.27 mm 2 , p&lt; 0.01 and 24.0±7.0 vs. 17.4±3.6 %, p&lt; 0.01, respectively).Furthermore, when lesions were divided in 3 groups (group of PLIA score 0, N=15; group of 0&lt;PLIA score&lt;1, N=20; group of 1 &lt; PLIA score, N=15), mean- and percent- neointima area were different among 3 groups (1.51±0.27 vs.1.66±0.39 vs.2.39±0.73 mm 2 , p&lt;0.01; 17.4±3.7 vs.21.6±5.0 vs. 27.4±8.1 %, p&lt;0.01). Conclusion: The presence and extent of PLIA after BRS implantation on OCT imaging appeared to be significantly associated with neointimal formation.

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

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). 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. 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.

Optical Coherence Tomography Findings in Bioresorbable Vascular Scaffolds Thrombosis.

Everolimus-eluting bioresorbable vascular scaffolds have been developed to improve late outcomes after coronary interventions. However, recent registries raised concerns regarding an increased incidence of scaffold thrombosis (ScT). The mechanism of ScT remains unknown. The present study investigated angiographic and optical coherence tomography findings in patients experiencing ScT. Fifteen ScT (14 patients, 79% male, age 59±10 years) occurred at a median of 16 days (25%-75% interquartile range: 1-263 days) after implantation. Early ScT (<30 days) occurred in 8 cases (53%). Possible causal factors in these patients included insufficient platelet inhibition in 2 cases and procedural factors (scaffold underexpansion, undersizing, or geographical miss) in 4 cases. No obvious cause could be found in 2 early ScT. In late (>1 month) and very late (>1 year) ScT (respectively, 5 and 2 cases), 5 scaffolds showed intimal neovessels or marked peristrut low-intensity areas. Scaffold fractures were additionally found in 2 patients, and scaffold collapse was found in 1 patient with very late ScT. Extensive strut malapposition was the presumed cause for ScT in 1 case. One scaffold did not show any morphological abnormality. Thrombectomy specimens were analyzed in 3 patients and did not demonstrate increased numbers of inflammatory cells. The mechanisms of early ScT seem to be similar to metallic stents (mechanical and inadequate antiplatelet therapy). The predominant finding in late and very late ScT is peristrut low-intensity area.

TCT-50 Peri-strut Low Intensity Area Assessed By Mid-term Follow-up Optical Coherence Tomography May Predict Target Lesion Revascularization After Stent Implantation

TCT-50 Peri-strut Low Intensity Area Assessed By Mid-term Follow-up Optical Coherence Tomography May Predict Target Lesion Revascularization After Stent Implantation

Optical coherence tomography study of chronic-phase vessel healing after implantation of bare metal and paclitaxel-eluting self-expanding nitinol stents in the superficial femoral artery

BackgroundThis study aimed to assess chronic-phase suppression of neointimal proliferation and arterial healing following paclitaxel-coated (PTX) and bare metal stent (BMS) implantation in the superficial femoral artery using optical coherence tomography (OCT). MethodsTwenty-five patients with 68 stents underwent an 8-month OCT follow-up. Besides standard OCT variables, neointimal characterization and frequencies of peri-strut low-intensity area (PLIA), macrophage accumulation, and in-stent thrombi were evaluated. ResultsThe mean neointimal thickness was significantly less with PTX stents (544.9±202.2μm vs. 865.0±230.6μm, p<0.0001). The covered and uncovered strut frequencies were significantly smaller and larger, respectively, in the PTX stent group vs. the BMS group (93.7% vs. 99.4%; p<0.0001, 4.0% vs. 0.4%; p<0.0001, respectively). Heterogeneous neointima was only observed in the PTX stent group (12.5% vs. 0%, p=0.017). The frequencies of PLIA and macrophage accumulation were significantly greater in the PTX stent group (87.2% vs. 67.6%, p=0.001 and 46% vs. 9.1%, p=0.003, respectively). ConclusionAfter 8 months, reduced neointimal proliferation was observed with PTX stent implantation. On the other hand, delayed arterial healing was observed compared with BMS.

Serial Optical Coherence Tomography Evaluation at 6, 12, and 24 Months After Biolimus A9-Eluting Biodegradable Polymer-Coated Stent Implantation

BackgroundThe Nobori (Terumo Corporation, Tokyo, Japan) is a biolimus A9-eluting stent (BES) featured with a biodegradable polymer coated on the abluminal side only. We previously reported that favourable vessel healing was achieved at 6-12 months after BES implantation. However, detailed long-term vessel reaction after BES deployment is unclear. MethodsTwenty-two BESs were serially evaluated using optical coherence tomography (OCT) at 6, 12, and 24 months after stenting. Average neointimal thickness, uncovered struts, and neointimal unevenness score (each cross-section as maximum neointimal thickness in 1 cross section divided by the average neointimal thickness of the same cross-section) were manually measured. In addition, we evaluated the percentage of struts with peri-strut low-intensity area (a region around stent struts that homogenously showed less intensity than the surrounding tissue, which suggests fibrin deposition or impaired neointima maturation), thrombi, and atherogenic neointimas (neointimas containing a diffuse border and poor-signal region with invisible struts due to marked signal attenuation). ResultsSerial OCT observation revealed a small gradual increase in neointimal thickness from 6 to 24 months (73 ± 24 μm; 81 ± 26 μm; and 108 ± 35 μm, respectively, P = 0.001) with a nonsignificant decrease in the lumen area (6.36 ± 1.98 mm2; 6.18 ± 2.04 mm2; and 5.87 ± 2.06 mm2; P = 0.72). Frequency of uncovered struts (3.89 ± 3.91%; 1.55 ± 1.63%; and 0.23 ± 0.67%; P = 0.001), neointimal unevenness score (1.95 ± 0.18% to 1.86 ± 0.19% to 1.78 ± 0.17; P = 0.012), percentage of thrombi (5%, 0%, and 0%; P = 0.37) and peri-strut low-intensity area (6.8%, 5.1%, and 1.6%; P = 0.017) decreased from 6 to 12 and 24 months. Atherogenic neointima was not observed in the event-free OCT cohort. ConclusionsThe Nobori stent achieved acceptable long-term vessel healing, mostly without adverse vessel reactions.

Vascular Response After Zilver PTX Stent Implantation for Superficial Femoral Artery Lesions

Purpose: To compare the vascular response after paclitaxel-coated nitinol drug-eluting stent (Zilver PTX) implantation for superficial femoral artery lesions after 6 and 12 months using optical coherence tomography (OCT). Methods: Serial OCT examinations were performed in 5 patients (4 men; mean age 78.4±6.8 years) with 9 Zilver PTX stents at 6- and 12-month follow-up. Variables evaluated included neointimal thickness and apposition on each strut, the incidence of extrastent lumen (ESL), peristrut low-intensity area (PLIA), and neovascularization at 1-mm intervals. Results: A total of 249 matched cross-section images were evaluated and included 4788 and 4826 struts at 6 and 12 months, respectively. Mean neointimal thickness significantly increased from 480 to 540 µm between 6 and 12 months (p<0.001). The percentage of uncovered struts tended to decrease at 12 months (3% vs. 2.3%, p=0.054), whereas the percentage of malapposed struts were similar at both examinations (0.2% vs. 0.2%, p>0.99). Although the incidence of ESL in cross sections was not different (35% vs. 31%, p=0.29), median ESL area significantly increased from 6 to 12 months [0.12 (0.04–0.36) vs. 0.31 (0.14–0.59) mm2, p=0.003)]. The presence of PLIA (29% vs. 44%, p<0.001) and neovascularization (14% vs. 27%, p<0.001) increased from 6 to 12 months. Conclusion: These findings suggest that delayed vascular healing and persistent peristent inflammation may be present even at 12 months after Zilver PTX implantation.