Visible Struts Research Articles

Optical coherence tomography characterization of degradation kinetics between second- and third-generation resorbable magnesium scaffold.

This preclinical study aimed to establish optical coherence tomography (OCT)-derived parameters that could be used in the clinical setting for assessing strut degradation in the third-generation drug-eluting resorbable magnesium scaffold (DREAMS-3G), and characterize the comparative degradation profile against its precursor device (MagmarisTM scaffold). Twelve DREAMS-3G and 10 MagmarisTM scaffolds were implanted in juvenile pigs, and OCT images obtained at baseline and follow-up (6 or 12 months). Strut degradation was assessed by planimetric analysis and compared with OCT-derived indices to validate their diagnostic accuracy. A total of 3327 struts of DREAMS-3G and 2995 struts of the MagmarisTM scaffold were delineated by OCT. DREAMS-3G exhibited a significantly higher number of visible struts per analyzed frame at 6 months than the MagmarisTM scaffold, in the absence of significant differences at 12 months. Attenuation index (AtI) analysis indicated DREAMS-3G degradation was less advanced at 6 months but more advanced at 12 months compared to the MagmarisTM scaffold. These OCT-derived indices significantly correlated with the results of the planimetric analysis. The current preclinical study validated OCT indices that may serve as clinical surrogate markers for scaffold degradation. AtI analysis indicated that DREAMS-3G showed less degradation at 6 months but more advanced degradation at 12 months compared to the MagmarisTM scaffold, which corroborates the findings from planimetric analysis.

Twelve-months vessel healing profile following the novel resorbable magnesium scaffold implantation: an intravascular OCT analysis of the BIOMAG-I trial

Abstract Background The first-in-human trial of the latest resorbable magnesium scaffold (RMS), DREAMS 3G, showed favorable clinical and angiographic outcomes up to 6-months. An intravascular optical coherence tomography (OCT) assessment of the vascular healing profile at 6 months and 12 months follow-up may serve as additional supportive evidence for device safety and efficacy. Purpose The aim of this study was to evaluate the vessel healing process by quantifying the presence of strut protrusion (SP) and strut degradation following DREAMS 3G implantation as per intravascular OCT imaging. Methods Patients from the BIOMAG-I trial who underwent OCT imaging at both 6- and 12-months were deemed eligible. This resulted in the inclusion of a total of 51 patients and 52 lesions in the current analysis. The acquired intravascular imaging data were evaluated every 1 mm to visualize and quantify the SP and the number of visible struts at 6- and 12-months. In addition, we investigated the potential impact of SP on mean and minimum lumen area (mm2) at both time point. Results At 12 months, the mean SP area was significantly smaller in comparison to 6 months follow-up (1.87±2.22 mm2 at 6 months vs. 0.99±1.27 mm2 at 12 months, p<0.001). There was a positive correlation between SP area and mean lumen area at both 6 months (p<0.001) and 12 months (p=0.014) follow-up. Similarly, a positive correlation was observed between SP area and minimum lumen area up to 6 months (p=0.006 at 6 months, p=0.323 at 12 months). The number of visible struts was 6.44±7.59 at 6 months and 1.79±0.85 at 12 months (p<0.001). Conclusion The SP area was larger in lesions with greater lumen area following the implantation of the novel RMS. The observed SP area was significantly smaller at 12 months in comparison to 6 months follow-up. These results suggest that the presence of SP is part of a favorable vascular healing process following the treatment with the latest resorbable magnesium scaffold.

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.

P3389Angioscopic differences in quality and quantity of neointima in patients experiencing an acute coronary syndrome treated with bare metal, first-, second-, and third generation drug-eluting stents

Abstract Background Although drug-eluting stents (DES) have substantially reduced the need for early target lesion revascularization (TLR) compared with bare-metal stents (BMS) by inhibiting neointima hyperplasia, early generation DES have been associated with an increased risk of very late stent failure (VLSF) due to stent thrombosis and TLR after 1 year. Although the incidence of VLSF is reduced with newer generation DES, VLSF remains an unresolved problem and its mechanisms are not fully explored. Purpose The purpose of this study was to evaluate quality and quantity of neointima and presence of thrombus by using coronary angioscopy at long-term follow-up in patients who experienced an acute coronary syndrome (ACS) treated with BMS and DES on dual antiplatelet therapy. Methods Coronary angioscopy was performed at 6 and 10 months after BMS and DES implantation, respectively, in ACS patients. We assessed neointimal coverage (NC) of the stent struts, yellow color grade (YG) of stented segment and the existence of thrombus. Angioscopic NC was defined as follows: grade 0= fully visible struts; grade 1= visible struts through thin neointima; grade 2= no visible struts. We determined maximum (Max-NC) and minimum coverage (Min-NC) grades and the dominant NC grades. YG was classified into 4 grades (0= white; 1= slight yellow; 2= yellow; 3= intensive yellow). The obtained findings were compared with BMS, first-generation (1st-) DES, second-generation (2nd-) DES and third-generation (3rd-) DES. Results A total of 212 patients were enrolled: BMS (n=127), 1st DES (n=26, sirolimus-eluting stent), 2nd-DES (n=38, permanent polymer everolimus-eluting stent), and 3rd-DES (n=21, bioresorbable polymer everolimus-eluting stent). Max-NC and Min-NC grade were significantly lower with 1st- and 2nd-DES than with BMS and 3rd-DES (Figure). The same trend was also observed in the dominant NC grades. There was a lower trend of YG in BMS and 3rd-DES than in 1st or 2nd-DES (Figure). The presence of thrombus was significantly lower in 3rd-DES in comparison with BMS, 1st-, and 2nd-DES (3rd-DES 0%, BMS 20.5%, 1st-DES 24%, 2nd-DES 13.5%, P=0.01). Figure 1 Conclusion Patients treated with 3rd-DES have higher NC grade, lower incidence of intrastent thrombus, and lower YG than in 1st and 2nd-DES. These findings may explain the lower incidence of VLSF associated with these newer generation stent platforms.

Gradual expansion of stent retriever in mechanical thrombectomy for curved middle cerebral artery: structural findings of the stent for predictable recanalization results.

Trevo Provue stent retriever with visible struts under fluoroscopy may be useful in identifying the optimal position and expansion of the stent during the procedure. This study aimed to demonstrate and analyze changes in the segmental diameter of a radio-opaque stent retriever after deployment according to recanalization results, and its relationship with the angle of the occluded segment of the middle cerebral artery (MCA). Forty-one patients who underwent mechanical thrombectomy using a Trevo stent retriever were divided into two groups according to Thrombolysis in Cerebral Infarction (TICI) score (TICI 0-2a and TICI 2b/3). The proximal (Pt), middle (Mt), and distal diameter (Dt) of the deployed stent, at three post-deployment waiting times (t = 0, 3, and 5min), were measured, and ratios of Mt to Pt (Mt/Pt) and of Mt to Dt (Mt/Dt) were calculated. TICI 2b/3 was achieved in 31 patients (75.6%) and TICI 0-2a in 10 patients (24.4%). In the TICI 2b/3 group, both changes of Mt/Pt (P < 0.001) and Mt/Dt (P = 0.001) until 3min were significant and all Mt/Pt (each P < 0.01), M3/D3 (P = 0.014), and M5/D5 (P = 0.012) were significantly larger than those in the TICI 0-2a group. The angle of the MCA was significantly correlated with Mt/Pt and Mt/Dt (P <0.001). The diameter of the stent retriever after deployment was associated with the recanalization results in mechanical thrombectomy following MCA occlusion.

Extreme late-phase observation using coronary angioscopy until 7 years after sirolimus-eluting stent implantation.

Little is known about the very late-phase morphological vessel characteristics within the sirolimus-eluting stent (SES). We assessed a total of 12 patients with 15 SES implantations who underwent repeat angiographic and angioscopic procedures after 5 and 7 years. The degree of neointimal stent coverage (NSC) was classified as follows: grade 0, uncovered struts; grade 1, visible struts through a thin neointima; or grade 2, invisible struts with complete neointimal coverage. The maximum and minimum NSC grades were evaluated and the existence of in-stent thrombus was also recorded for all patients. The prevalence of a maximum NSC grade of 2 increased and that of a minimum NSC grade of 0 decreased, although there was no significant difference in prevalence between 5 and 7 years. One of four in-stent thrombus identified at 5 years had disappeared from 5 to 7 years and a new thrombus was found in another patient at 7 years. Thus, the incidence of in-stent thrombus did not change from 5 to 7 years. In one case, a thrombus was observed inside the angiographic aneurysmal change, but none of the thrombi were related to adverse events. This angioscopic study reported gradual arterial repair and continuous delayed healing associated with subclinical thrombus formation 7 years after SES deployment.

Tissue Characterization of In-Stent Neointima Using Optical Coherence Tomography in the Late Phase After Bare-Metal Stent Implantation--An Ex Vivo Validation Study.

We performed an ex vivo study to investigate optical coherence tomography (OCT) imaging for differentiating several types of neointimal tissue during the later phases after bare-metal stent (BMS) implantation as compared with histologic results. OCT imaging was performed in 6 autopsy hearts for 10 BMS with implant duration >4 years. OCT qualitative neointimal tissue characterization was based on tissue structure and classified as homogeneous pattern, heterogeneous pattern with visible struts, or heterogeneous pattern with invisible struts. Corresponding histological analyses of each 2-mm cross-section of the entire BMS were performed. Of 81 cross-sections, histological analysis revealed that the homogeneous pattern of neointima on OCT (n=39) contained smooth muscle cells with collagen, indicating high neointimal maturity. The heterogeneous patterns with visible struts (n=35) contained different tissues, including a proteoglycan-rich myxomatous matrix or dense calcified plate deposition. The heterogeneous patterns with invisible struts (n=7) included neointimal lipid/necrotic core formation, accumulation of foam cells, or microcalcification scattering. Of the 66 cross-sections containing large microvessels within the neointima on histology, only 6 (9%) were visualized by OCT. The present study confirmed the potential use of OCT in differentiating several types of neointima after BMS implantation. The image interpretation of OCT, based on visualization of stent struts, enables identification of several types of neointimal tissues, including in-stent fibroatheroma formation, more accurately.

Tissue coverage of paclitaxel and sirolimus eluting stents in long term follow-up: Optical coherence tomography study

Implantation of drug eluting stents (DES) has become a standard treatment of patients undergoing percutaneous coronary intervention (PCI). Incomplete strut coverage is a potential risk factor for late stent thrombosis. Optical coherence tomography (OCT) enables in vivo identification of incomplete neointimal coverage. Study included 62 patients after sirolimus eluting stents (SES) or paclitaxel eluting stents (PES) implantation. OCT examination was performed at least 24 months after the initial procedure (35.4± 9.4 months). In cross-sectional still frames selected from each 1 mm of analyzed stents a total number of visible struts and number of struts with or without complete neointimal coverage was assessed. Measurements of neointimal coverage, presented as a mean thickness of tissue, were performed. Patients were followed up for 3 years and the frequency ofmajor adverse cardiac events was recorded. In the analyzed 28 SES and 37 PES 9998 struts were identified. Complete neointimalcoverage was observed in 83.5% and 79.2% of SES and PES struts respectively (p = 0.48).There was no difference in incidence of not covered or malapposed struts between SES and PES groups. Mean thickness of the tissue covering SES struts was 0.165 ± 0.095 mm, and 0.157 ± 0.121 mm for PES. The mean neointimal thickness difference (SES vs. PES) was notstatistically significant. In a 36 months follow-up 1 death was observed - potentially attributed to stent thrombosis. A long term OCT follow-up after DES implantation shows high incidence ofuncovered struts regardless of the stent type. Clinical significance of this finding remains questionable and requires further large scale trials.

Coronary angioscopic findings 9 months after everolimus-eluting stent implantation compared with sirolimus-eluting stents

We assessed angioscopic findings after everolimus-eluting stents (EES) implantation, compared with sirolimus-eluting stents (SES). Coronary angioscopy (CAS) provides an opportunity to assess neointimal coverage over stent struts, thrombus, and plaque color by direct visualization. CAS is a useful tool for evaluating stent struts after drug-eluting stent implantation. Angioscopic findings after EES implantation have not been reported before. We performed CAS in 23 patients who were treated with EES and 41 patients with SES. CAS was performed 8.5 months after stent implantation. We assessed neointimal coverage, thrombus, and plaque color. We classified neointimal coverage in 4 grades: grade 0=struts were completely exposed; grade 1=struts were visible with dull light reflexion; grade 2=there was no light reflexion from slightly visible struts; grade 3=struts were completely covered. There was no significant difference in minimum, maximum, dominant grade of neointimal coverage, and heterogeneity index between EES and SES. Thrombus was less frequently observed in EES than SES (4% vs 29%, p=0.02). When we divided study patients into acute coronary syndrome (ACS) or stable angina pectoris (SAP), there was a tendency toward less thrombus in EES than SES, in both ACS and SAP. Maximum color grade of the plaques was less advanced in EES than SES (p<0.01). Yellow plaques of grade 2 or 3 were less frequent in EES than SES (35% vs 76%, p<0.01). This study suggested that EES were associated with lower risk of thrombus formation than SES.

The possibility of delayed arterial healing 5 years after implantation of sirolimus-eluting stents: Serial observations by coronary angioscopy

Although very late stent thrombosis occurs several years after implantation of sirolimus-eluting stent (SES), the morphologic changes of the stent beyond 2 years have not yet been systematically studied in living patients. The late vascular response to SES was therefore evaluated by serial angioscopic studies at 2 and 5 years after stent implantation. A total of 17 patients with 17 SES underwent a repeated angioscopy procedure at 2 and 5 years. Neointimal stent coverage (NSC) was classified as follows: grade 0, presence of uncovered struts; grade 1, visible struts through a thin neointima; or grade 2, complete neointimal coverage without visible struts. For each patient, the minimum and maximum NSC grade and the existence of in-stent thrombus were recorded. The minimum and maximum NSC grade did not increase between the 2 and 5 years (0.59 ± 0.51 vs 0.88 ± 0.70, P = .17, and 1.82 ± 0.39 vs 1.94 ± 0.24, P = .30, respectively). The prevalence of patients with uncovered struts did not significantly decrease from 2 to 5 years (41% vs 29%, P = .49). During the follow-up period, 3 of 6 thrombi disappeared, whereas new thrombus formation was found in 3 patients without any clinical symptoms. In-stent thrombus did not decrease (35% vs 35%, P > .99). The current serial angioscopic study suggests that incomplete NSC and the prevalence of latent thrombus within the SES segments did not decrease from 2 to 5 years. The risk of stent thrombosis related to incomplete healing of SES may continue for an extended period.

Angioscopic Assessment of Arterial Repair Following Biodegradable Polymer-Coated Biolimus A9-Eluting Stent Implantation - Comparison With Durable Polymer-Coated Sirolimus-Eluting Stent -

Second-generation drug-eluting stents (DES) are expected to show better arterial repair than older DES. We angioscopically compared the biodegradable polymer-coated biolimus A9-eluting stent (BES) and durable polymer-coated sirolimus-eluting stent (SES) to explore differences in arterial repair. Angioscopy was performed 9 ± 1 months after 15 BES and 16 SES were implanted initially in the native coronary artery. Heterogeneity of neointimal coverage (NIC) as well as the dominant NIC grade was examined. NIC was defined as: grade 0 = fully visible struts; grade 1 = struts bulging into the lumen, but covered; grade 2 = embedded, but translucent struts; grade 3 = invisible struts. Heterogeneity was judged when the NIC grade varied ≥ 1. In-stent late loss (0.06 ± 0.23 vs. 0.07 ± 0.18 mm, P = 0.80), and dominant NIC grade (1.5 ± 0.8 vs. 1.3 ± 0.7, P = 0.45) were similar for BES and SES. Within the stents, NIC was more heterogeneous in SES than in BES (P = 0.035). 80% of BES showed homogeneous NIC, while 56% of SES had heterogeneous NIC. BES showed limited late loss similar to that for SES. Nonetheless, the NIC with BES was more homogeneous than that with SES. Biodegradable polymer-coated BES may have an advantage in homogeneous NIC.

Relation of Drug-Eluting Stent Strut Distribution to Stent Thrombosis in Coronary Arteries

The distribution of stent struts is critical to drug deposition and, therefore, may affect the amount of neointima and the risk of thrombosis after drug-eluting stent (DES) implantation. The aim of our study was to evaluate stent strut distribution in the setting of a drug-eluting stent thrombosis (ST). We retrospectively analyzed postprocedural intravascular ultrasound (IVUS) images of 13 patients who subsequently developed ST (14 DES thrombotic lesions) and a control group of 27 patients (30 DES lesions) matched for stent type and presence of chronic renal failure. In addition to standard IVUS measurements, visible struts were counted and maximum interstrut angle was measured at 1-mm intervals. Early ST was defined as < or =30 days after DES deployment and late ST as >30 days after DES deployment. Compared with DES controls, the ST group had a larger maximum interstrut angle (60.8 +/- 8.3 degrees vs 55.7 +/- 4.8 degrees , p = 0.014) and a similar number of stent struts (8.4 +/- 0.6 vs 8.7 +/- 0.6, p = NS). Maximum interstrut angle tended to be larger in late ST than in early ST (66.1 +/- 10.8 degrees vs 57.8 +/- 5.0 degrees , p = 0.071). The incidence of maximum interstrut angles > or =90 degrees and > or =120 degrees observed continuously for > or =2 mm of stent length was higher in the ST group (p = 0.009 and p = 0.096, respectively). In conclusion, DES-treated lesions leading to ST had larger maximum interstrut gaps distributed circumferentially and longitudinally, but a similar number of struts at the time of DES implantation compared with DES controls.

Heterogeneous Arterial Healing in Patients Following Paclitaxel-Eluting Stent Implantation: Comparison With Sirolimus-Eluting Stents

We angioscopically compared paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) to explore differences in arterial healing. Drug-eluting stents may demonstrate different arterial healing processes. Angioscopy was performed 9 +/- 2 months after 30 PES and 36 SES were implanted initially in the native coronary artery. Heterogeneity of the neointimal coverage (NIC) as well as the dominant grade was examined. Neointimal coverage was defined as follows: grade 0 = fully visible struts; grade 1 = struts bulged into the lumen, but covered; grade 2 = embedded, but translucent struts; grade 3 = invisible struts. Heterogeneity was judged when the NIC grade variation >or=1. Thrombi and yellow plaques (YP) were also explored. In-stent late loss (0.44 +/- 0.44 mm vs. 0.13 +/- 0.33 mm; p < 0.0001) and dominant NIC grade (1.8 +/- 1.1 vs. 1.3 +/- 0.7; p = 0.02) were greater in PES than in SES. Of PES, 48% showed the heterogeneity of 1 grade; 26% showed that of 2 grades. Of SES, 53% showed homogeneous coverage; the remaining SES showed the heterogeneity of 1 grade; and 72% showed dominant grade 1. Thrombi were more common in PES than in SES (43% vs. 19%; p = 0.04). Both stents commonly revealed YP (83% vs. 78%; p = 0.76). NIC was more heterogeneous in PES, associated with a higher incidence of thrombi. Homogeneous NIC may be an important factor for competent arterial healing.

Abstract 5999: Optical Coherence Tomography Findings At Two Years Follow Up In Fully Biodegradable Everolimus Eluting Stents

Fully biodegradable stents may avoid the potential long-term complications of metallic drug-eluting stents such as late and very late stent thrombosis. We sought to evaluate the structural changes in a bioabsorbable DES and its interaction with the coronary vessel wall over time using optical coherence tomography (OCT). We investigated 14 consecutive patients undergoing implantation of a bioabsorbable everolimus-eluting coronary stent (BVS: Abbott Laboratories, IL, USA), composed of a poly-L-lactic acid backbone, coated with a degradable polymer/everolimus matrix. OCT (LightLab Imaging, Inc., Westford, MA) was performed immediately after stent implantation, at 6 months and at 24 months follow-up. All patients tolerated OCT imaging without complications. At baseline, OCT could detect the interface between the BVS stent and other tissues or fluid, but the inside of the strut appeared black, giving a unique box appearance. After 6 months, the struts were still clearly visible; however, their optical properties had changed considerably. In patients undergoing two years follow up (n=5, full dataset will be available at time of presentation) the majority of struts was not visible anymore and all visible struts were embedded into the vessel wall with complete tissue coverage. In contrast to 6months follow-up, at 2 years no intraluminal thrombi or dissections were visible. At 2 years follow-up the majority of stent struts were not visible by OCT. All the visible struts were covered and apposed. The lumen surface was smooth without intraluminal thrombi or dissections.

Lack of Association Between Large Angiographic Late Loss and Low Risk of In-Stent Thrombus

Background— It recently has been hypothesized that a larger late loss may have a protective role against stent thrombosis. The relationship between angiographic late loss and the presence of thrombus based on angioscopic findings within paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) was investigated in this study. Methods and Results— Prospective 6-month follow-up angiographic and angioscopic examinations were performed on 18 patients for PES and on 20 patients for SES. Late loss was measured by quantitative coronary angiography. Angioscopic neointimal stent coverage (NSC) grade was classified as follows: 0=uncovered struts without neointima, 1=visible struts through thin neointima, and 2=no visible struts. In each patient, maximum NSC, minimum NSC, and the existence of thrombus were evaluated. Late loss and maximum NSC were greater in PES than in SES (0.38�0.43 versus 0.10�0.23 mm; P =0.02 and P =0.0004, respectively). Late loss was correlated with maximum NSC (grade 0, 0.06�0.01 mm; grade 1, 0.10�0.05 mm; and grade 2, 0.48�0.46 mm), whereas there was no correlation between late loss and minimum NSC. The prevalence of patients with uncovered struts did not differ (44% of PES, 40% of SES; P =0.78). In-stent thrombus was found more frequently in PES than in SES (72% versus 40%, P =0.046) despite no occurrence of stent thrombosis. Only within PES were thrombi found in the segments of NSC grade 2 associated with large late loss. Conclusion— The present study suggests that angiographic large late loss was not associated with a low risk of in-stent thrombus.

Serial long-term evaluation of neointimal stent coverage and thrombus after sirolimus-eluting stent implantation by use of coronary angioscopy

Objective:Progression of neointimal stent coverage (NSC) and changes in thrombus were evaluated serially by coronary angioscopy for up to 2 years after sirolimus-eluting stent (SES) implantation.Design:Serial angioscopic observations were performed...

Abstract 3164: Angioscopic Findings of Sirolimus-Eluting Stent for Acute Myocardial Infarction: An Intermediate-term Follow-up Study

Background: Sirolimus-Eluting Stent (SES) is effective in reducing restenosis. Although several studies have reported the usefulness of SES in patients with acute myocardial infarction (AMI), the current major concerns of the use of SES in AMI are over-suppression of neointimal formation and late thrombosis. Coronary angioscopic examination provides an opportunity to assess neointimal coverage over stent and adherent thrombus in patients. Method: This study consisted of 18 patients who underwent primary angioplasty with SES for AMI. A mean average of 7.6 ± 2.5 months after SES implantation, coronary angioscopic examination was performed. Neointimal coverage of the SES was assessed by the grading as: grade 0 = complete exposure of the stent struts, grade 1 = dull light reflex from stent struts, grade 2 = no light reflex, but slightly visible stent struts, and grade 3 = complete coverage. Because the grade of neointimal coverage may vary from struts to struts, both maximum and minimum grade of neointimal coverage were assessed. The presence of thrombus was also evaluated. Results: All but one patient had at least 2 different grades of neointimal coverage; one patient had only grade 0. When the maximum grade of neointimal coverage was assessed, grade 0 was observed in 1 patient, grade 1 in 4 patients, grade 2 in 8 patients, and grade 3 in 5 patients. As to minimum grade, grade 0 was observed in 11 patients and grade 1 in 7 patients, however, grade 2 and 3 was not observed. Thrombus adherent to uncovered stent struts (grade 0 or 1) was observed in 8 patients (44%). Conclusion: The process of neointimal coverage over SES was heterogeneous. Even 7 months after SES implantation for AMI, most of the stent struts were not covered by neointimal with high incidence of adherent thrombus. Long-term aggressive anti-platelet therapy should be advocated for patients with AMI who were treated with SES.

Serial long-term evaluation of neointimal stent coverage and thrombus after sirolimus-eluting stent implantation by use of coronary angioscopy

Objective:Progression of neointimal stent coverage (NSC) and changes in thrombus were evaluated serially by coronary angioscopy for up to 2 years after sirolimus-eluting stent (SES) implantation.Methods:Serial angioscopic observations were performed...

Angioscopic differences in neointimal coverage and in persistence of thrombus between sirolimus-eluting stents and bare metal stents after a 6-month implantation

The neointimal coverage and intracoronary thrombi within stented segments at 6 months after implantation between sirolimus-eluting stents (SESs) and bare metal stents (BMSs) were compared by direct visualization using angioscopy. Forty-six patients (36 stable angina and 10 acute coronary syndrome) were treated with 33 SESs and 33 BMSs. Immediately after and 6 months after stenting, each of the stented segments, edge body, and overlapping segment were observed by angioscopy and the grade of neointimal coverage over the stents was classified as 0: absent neointima, 1: visible struts through thin neointima, or 2: invisible struts. The existence of thrombi was also evaluated. The average grade of the neointimal coverage at 6 months follow-up was lower in the SES than that in the BMS (edge: 1.4+/-0.7 vs. 1.9+/-0.2, body: 1.0+/-0.5 vs. 1.8+/-0.5, overlapping segment: 0.6+/-0.7 vs. 1.8+/-0.5; P<0.0001, P<0.0001, P=0.0069, respectively). The frequency of persistence of thrombus was significantly higher in the SESs than that in the BMSs (86 vs. 29%, respectively; P=0.031). The present study suggested a delayed neointimal stent coverage and slower thrombus disappearance process in the SESs in comparison to the BMSs.

Nonuniform Strut Distribution Correlates With More Neointimal Hyperplasia After Sirolimus-Eluting Stent Implantation

Little is known about causes of intimal hyperplasia (IH) after sirolimus-eluting stent (SES) implantation. Intravascular ultrasound was performed in 24 lesions with intra-SES restenosis and a comparison group of 25 nonrestenotic SESs. To assess stent strut distribution, the maximum interstrut angle was measured with a protractor centered on the stent, and the visible struts were counted and normalized for the number of stent cells. In SES restenosis patients, minimum lumen site was compared with image slices 2.5, 5.0, 7.5, and 10.0 mm proximal and distal to this site. The minimum lumen site had a smaller IVUS lumen area at follow-up (2.7+/-0.9 versus 6.2+/-1.9 mm2; P<0.01), larger maximum interstrut angle (135+/-39 degrees versus 72+/-23 degrees; P<0.01), larger IH area (3.4+/-1.5 versus 0.6+/-1.1 mm2; P<0.01) and thickness (0.7+/-0.3 versus 0.1+/-0.2 mm; P<0.01) at maximum interstrut angle, and fewer stent struts (4.9+/-1.0 versus 6.0+/-0.5; P<0.01) even when normalized for the number of stent cells (0.78+/-0.15 versus 0.97+/-0.07; P<0.01). Compared with nonrestenotic SES, the restenosis lesions also had a smaller minimal lumen area, larger IH area, thicker IH at maximum interstrut angle, fewer stent struts, and larger maximum interstrut angle. Multivariate analysis identified the number of visualized stent struts normalized for the number of stent cells and maximum interstrut angle as the only independent IVUS predictor of IH cross-sectional area (P<0.01 and P<0.01), minimum lumen area (P<0.01 and P<0.01), and IH thickness (P<0.01 and P<0.01). The number and distribution of stent struts affect the amount of neointima after SES implantation.