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

BACKGROUND: Uncovered struts are a determinant of stent failure. The impact of plaque composition and procedural factors on the occurrence, evolution, and outcomes of uncovered struts in a high-risk setting has not been investigated. OBJECTIVE: To investigate the determinants and long-term clinical impact of largely uncovered struts (LUS) in thin-struts drug-eluting stents (DES) implanted in complex lesions by intracoronary optical coherence tomography (OCT). METHODS: Ninety patients with multivessel disease undergoing staged complete revascularization were randomly assigned to bioabsorbable or durable polymer DES. OCT were serially performed during the index procedure, at 3- and 18-month follow-up, and analyzed by an independent core lab. Struts were defined uncovered by OCT if no tissue was visible above the struts. LUS were defined as ≥30% of uncovered struts at 3-month follow-up. Clinical outcomes were the occurrence of target vessel failure (TVF) and major adverse cardiac and cerebrovascular events (MACCE) at 5-year follow-up. RESULTS: LUS occurred in 31 patients (34.4%) regardless of stent platform. At 5 years, no differences were observed in the rate of TVF (12.7% vs. 13.4%; p = 0.91) and MACCE (23.9% vs. 24.9%; p = 0.88) between the two groups. At multivariate logistic regression, plaque rupture, mean lumen diameter, proximal reference vessel area, and maximum stent deployment pressure were independent predictors of LUS. CONCLUSIONS: LUS are a frequent finding in complex coronary lesions treated with thin-struts DES, especially in the presence of plaque rupture. However, in this study, no significant safety signal related to LUS emerged in long-term follow-up.

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

BACKGROUND: Stent thrombosis (ST) is a serious complication following coronary stenting. Intravascular optical coherence tomography (OCT) may provide insights into mechanistic processes leading to ST. We performed a prospective, multicenter study to evaluate OCT findings in patients with ST. METHODS: Consecutive patients presenting with ST were prospectively enrolled in a registry by using a centralized telephone registration system. After angiographic confirmation of ST, OCT imaging of the culprit vessel was performed with frequency domain OCT. Clinical data were collected according to a standardized protocol. OCT acquisitions were analyzed at a core laboratory. Dominant and contributing findings were adjudicated by an imaging adjudication committee. RESULTS: Two hundred thirty-one patients presenting with ST underwent OCT imaging; 14 (6.1%) had image quality precluding further analysis. Of the remaining patients, 62 (28.6%) and 155 (71.4%) presented with early and late/very late ST, respectively. The underlying stent type was a new-generation drug-eluting stent in 50.3%. Mean reference vessel diameter was 2.9±0.6 mm and mean reference vessel area was 6.8±2.6 mm2. Stent underexpansion (stent expansion index <0.8) was observed in 44.4% of patients. The predicted average probability (95% confidence interval) that any frame had uncovered (or thrombus-covered) struts was 99.3% (96.1-99.9), 96.6% (92.4-98.5), 34.3% (15.0-60.7), and 9.6% (6.2-14.5) and malapposed struts was 21.8% (8.4-45.6), 8.5% (4.6-15.3), 6.7% (2.5-16.3), and 2.0% (1.2-3.3) for acute, subacute, late, and very late ST, respectively. The most common dominant finding adjudicated for acute ST was uncovered struts (66.7% of cases); for subacute ST, the most common dominant finding was uncovered struts (61.7%) and underexpansion (25.5%); for late ST, the most common dominant finding was uncovered struts (33.3%) and severe restenosis (19.1%); and for very late ST, the most common dominant finding was neoatherosclerosis (31.3%) and uncovered struts (20.2%). In patients presenting very late ST, uncovered stent struts were a common dominant finding in drug-eluting stents, and neoatherosclerosis was a common dominant finding in bare metal stents. CONCLUSIONS: In patients with ST, uncovered and malapposed struts were frequently observed with the incidence of both decreasing with longer time intervals between stent implantation and presentation. The most frequent dominant observation varied according to time intervals from index stenting: uncovered struts and underexpansion in acute/subacute ST and neoatherosclerosis and uncovered struts in late/very late ST.

Optical coherence tomography evaluation of late strut coverage patterns between first-generation drug-eluting stents and everolimus-eluting stent.

OBJECTIVES: To compare strut coverage patterns between everolimus-eluting stent (EES) and first-generation drug-eluting stents (DES) at more than 12 months after successful implantation, using optical coherence tomography (OCT). BACKGROUND: No sufficient OCT data has been reported comparing late strut coverage patterns between EES and first-generation DES. The favorable late results after EES implantation could be related to lower rates of uncovered and malapposed struts. METHODS: A total of 66 DES (21 EES, 23 SES, and 22 PES) that were implanted at least 1 year in advance in 40 patients and met good late angiographic results were evaluated by OCT. The percentage of uncovered and malapposed struts, calculated as the ratio of uncovered or malapposed struts to total struts in all cross-sectional images per stent, was compared among the three groups. RESULTS: A total of 35,061 struts were analyzed: 11,967 from EES, 11,855 from SES, and 11m239 from PES. The average tissue coverage thickness of the struts per stent was greater in EES than in SES and PES (109 ± 40 µm vs. 72 ± 27 µm and 83 ± 26 µm, respectively; P = 0.001). The percentage of uncovered struts (1.9 ± 4.1% in EES vs. 11.6 ± 12.7% in SES, P = 0.01 and vs. 7.1 ± 5.2% in PES, P < 0.001) and malapposed struts (0.1 ± 0.3% in EES vs. 1.8 ± 3.5% in SES, P = 0.01 and vs. 3.5 ± 5.1% in PES, P = 0.02) was much lower in EES than in first-generation DES, with no significant differences between SES and PES. CONCLUSIONS: Late strut coverage patterns are not similar between EES and first-generation DES. EES showed a lower percentage of uncovered and malapposed struts.

Optical coherence tomography tissue coverage and characterization at six months after implantation of bioresorbable scaffolds versus conventional everolimus eluting stents in the ISAR-Absorb MI trial.

PURPOSE: Data regarding vessel healing by optical coherence tomography (OCT) after everolimus-eluting bioresorbable scaffolds (BRS) or everolimus-eluting metallic stent (EES) implantation in acute myocardial infarction (AMI) patients is scarce. We compared OCT findings after BRS or EES implantation in patients with AMI enrolled in a randomized trial. METHODS: In ISAR-Absorb MI, AMI patients were randomized to BRS or EES implantation, with 6-8 month angiographic follow-up. This analysis includes patients who underwent OCT during surveillance angiography. Tissue characterization was done using grey-scale signal intensity analysis. The association between OCT findings and target lesion failure (TLF) at 2 years was investigated. RESULTS: OCT was analyzed in 103 patients (2237 frames, 19,827 struts) at a median of 216 days post-implantation. Of these, 70 were treated with BRS versus 32 with EES. Pre-(92.8 vs. 68.7%, p = 0.002) and post-dilation (51.4 vs. 12.5%, p < 0.001) were more common in BRS as compared to EES. Strut coverage was higher in BRS vs. EES (97.5% vs. 90.9%, p < 0.001). Mean neointimal thickness was comparable in both groups [85.5 (61.9, 124.1) vs. 69.5 (32.7, 127.5) µm, respectively, p = 0.20]. Mature neointimal regions were numerically more common in BRS (43.0% vs. 24.6%; p = 0.35); this difference was statistically significant in ST-elevation myocardial infarction patients (40.9% vs. 21.1%, p = 0.03). At two-years, 8 (7.8%) patients experienced TLF. Mean neointimal area [0.61 (0.21, 1.33) vs. 0.41 (0.11, 0.75) mm2, p = 0.03] and mean neointimal coverage [106.1 (65.2, 214.8) vs. 80.5 (53.5, 122.1) µm, p < 0.01] were higher, with comparable tissue maturity, in lesions with versus without TLF. CONCLUSIONS: In selected patients who underwent OCT surveillance 6-8 months after coronary intervention for AMI with differing implantation characteristics depending on the device type used, vessel healing was more advanced in BRS compared with EES, particularly in the STEMI subgroup.

Optical Coherence Tomography Tissue Coverage and Characterization with Grey-Scale Signal Intensity Analysis After Bifurcation Stenting with a New Generation Bioabsorbable Polymer Drug-Eluting Stent.

PURPOSE: Bifurcation stenting is thought to be associated with delayed healing and a subsequent risk of stent failure. The aim of this study was to further evaluate healing of thin-strut bioabsorbable polymer everolimus-eluting stents (EES) post bifurcation stenting by optical coherence tomography (OCT) including grey-scale signal intensity (GSI) analysis. METHODS: Patients undergoing bifurcation stenting with a planned two-stent approach using EES with OCT follow-up at 3-6 months post-stenting were included in this study. Morphometric analysis of contiguous cross-sections was performed at 1 mm longitudinal intervals within the stented segment. GSI analysis of neointimal regions of interest (ROI) overlying stent struts was performed for each of these cross-sections. Tissue coverage was classified as mature or immature. RESULTS: Data on a total of 31 lesions (17 cases) was available at a median of 168 days post stenting. Mean length of stented segments was 27.7 ±â€¯16.6 mm. The mean minimum stent area was 6.50 ±â€¯2.71 mm2 while the mean stent area was 8.69 ±â€¯3.08 mm2. Amongst a total of 847 assessed frames, 9716 struts were visible. Overall strut coverage was 95.9%; 0.3% of struts were malapposed. The mean thickness of neointimal coverage was 100.95 ±â€¯42.03 µm and the mean percentage area stenosis was 9.03 ±â€¯7.80%. A total of 53.79% of ROIs were classified as mature. CONCLUSIONS: After implantation of EES in bifurcation lesions, rates of uncovered and malapposed struts were low. GSI analysis showed that more than half of neointimal areas analyzed were classified as mature in keeping with advanced vessel healing.

Comparison of two different sampling intervals for optical coherence tomography evaluation of neointimal healing response after coronary stent implantation.

BACKGROUND/OBJECTIVES: Optical coherence tomography (OCT) is widely used for evaluation of healing response to stent implantation. We sought to test the agreement between the 1-mm and 0.6-mm sampling intervals for assessment of the percentage of uncovered and malapposed struts by OCT. METHODS: Thirty-eight patients presenting with acute coronary syndrome were randomized to receive either a titanium-nitride-oxide-coated stent (n=19) or an everolimus-eluting stent (n=19). Neointimal strut coverage and strut apposition were evaluated by OCT at 2-month follow-up. Two independent investigators performed offline OCT image analysis at 1-mm intervals. One investigator repeated the measurements at 0.6-mm intervals and measurements were compared between the two sampling intervals. RESULTS: At a median follow-up of 60 [8] days, 694 cross-sections (7603 struts) and 1138 cross-sections (12,331 struts) were analysed at 1-mm and at 0.6-mm intervals, respectively. The median [IQR] percentage of uncovered struts was 3.27% [11.1] versus 3.38% [9.76] (p=0.001), and the mean (±SD) percentage was 7.69±9.99% versus 6.27±8.14% (p=0.004), for the 1-mm sampling interval versus the 0.6-mm sampling interval analysis, respectively; the median percentage of malapposed struts was 0.42% [2.04] versus 0.12% [1.63], respectively, (p=0.003). The intraclass correlation coefficient between the two observers for the percentage of uncovered struts was 0.95. CONCLUSIONS: The OCT-evaluated strut-level measurements of neointimal healing after stent implantation differ significantly between the 1-mm and the 0.6-mm sampling intervals.

Vessel healings after stenting with different polymers in STEMI patients.

BACKGROUND: Different stents implantation in ST-segment elevation myocardial infarction (STEMI) patients may influence the long term prognosis by affecting vessel healings after stenting. The aim of this study was to evaluate the vessel healings after implantation of drug eluting stents (DES) with biodegradable or durable polymer or of bare-metal stents (BMS) in patients with acute STEMI. METHODS: This study included 50 patients, who underwent follow up angiogram and optical coherence tomography (OCT) assessment about one year after percutaneous coronary intervention (PCI) for STEMI. According to the initial stents types, these patients were classified to durable (n = 19) or biodegradable polymer sirolimus-eluting stents (n = 15), or BMS (n = 16) groups. The conditions of stent struts coverage and malapposition were analyzed with OCT technique. RESULTS: A total of 9003 struts were analyzed: 3299, 3202 and 2502 from durable or biodegradable polymer DES, or BMS, respectively. Strut coverage rate (89.0%, 94.9% and 99.3%, respectively), malapposition presence (1.7%, 0.03% and 0 of struts, respectively) and average intimal thickness over struts (76 ± 12 µm, 161 ± 30 µm and 292 ± 29 µm, respectively) were significantly different among different stent groups (all P < 0.001). CONCLUSIONS: Vessel healing status in STEMI patients is superior after implantation of biodegradable polymer DES than durable polymer DES, while both are inferior to BMS.