In the sputter deposition of cubic boron nitride (cBN) films using a boron carbide (B
4
C) target, the difference in the residual stress of the deposited cBN films was investigated when deposition ...was performed by RF sputtering and DC sputtering. The threshold bias voltage required to form the cBN phase was − 100 V for RF sputtering, significantly lower than − 220 V for DC sputtering, attributed to the ion density of the RF plasma being larger than that of the DC plasma at a deposition pressure of 2 mTorr. As a result of comparing the residual stress of the cBN thin films deposited under each cBN deposition condition, the residual stress generated in cBN films deposited by RF sputtering was lower than that of DC sputtering due to the relatively low bias voltage for cBN formation. Thus, it can be concluded that the RF plasma is preferable in terms of the lower residual stress of cBN compared with the DC plasma.
Graphical Abstract
Although intravascular ultrasound (IVUS) guidance has been useful in stenting for unprotected left main coronary artery stenosis, its impact on long-term mortality is still unclear.
In the ...MAIN-COMPARE registry, patients with unprotected left main coronary artery stenosis in a hemodynamically stable condition underwent elective stenting under the guidance of IVUS (756 patients) or conventional angiography (219 patients). Patients with acute myocardial infarction were excluded. The 3-year outcomes between the 2 groups were primarily compared using propensity-score matching in the entire and separate populations according to stent type. In 201 matched pairs of the overall population, there was a tendency of lower risk of 3-year morality with IVUS guidance compared with angiography guidance (6.0% versus 13.6%, log-rank P=0.063; hazard ratio, 0.54; 95% CI, 0.28 to 1.03; Cox-model P=0.061). In particular, in 145 matched pairs of patients receiving drug-eluting stent, the 3-year incidence of mortality was lower with IVUS guidance as compared with angiography guidance (4.7% versus 16.0%, log-rank P=0.048; hazard ratio, 0.39; 95% CI, 0.15 to 1.02; Cox model P=0.055). In contrast, the use of IVUS guidance did not reduce the risk of mortality in 47 matched pairs of patients receiving bare-metal stent (8.6% versus 10.8%, log-rank P=0.35; hazard ratio, 0.59; 95% CI, 0.18 to 1.91; Cox model P=0.38). The risk of myocardial infarction or target vessel revascularization was not associated with the use of IVUS guidance.
Elective stenting with IVUS guidance, especially in the placement of drug-eluting stent, may reduce the long-term mortality rate for unprotected left main coronary artery stenosis when compared with conventional angiography guidance.
Objectives
We aimed to assess the advantages of using the retrograde approach as an initial strategy rather than as a rescue strategy for complex chronic total occlusions (CTOs).
Background
Even for ...complex CTOs where a retrograde approach is deemed necessary, an antegrade approach is frequently used as an initial strategy in real‐world practice.
Methods
We evaluated 352 retrograde procedures for CTO conducted at our high‐volume center between January 2007 and January 2019. Procedural efficiency and safety was assessed based on the guidewire manipulation time (GWMT) and the occurrence of procedure‐related adverse events for the primary retrograde approach (PRA) and the rescue retrograde approach (RRA).
Results
PRA and RRA were used in 191 (54.3%) and 161 (45.7%) of the CTO procedures, respectively. The complexity of the CTO lesion was significantly higher in the PRA group than in the RRA group (Japanese‐CTO score, 2.62 ± 1.07 vs. 2.38 ± 1.06, p = 0.037). The technical success rate of two groups was similar (p = 0.47). The median GWMT required for PRA was significantly shorter than that for RRA (85 interquartile range, 55–126 vs. 120 85–157 min, p < 0.001). The total duration of the procedure and fluoroscopic time were shorter, and the number of guidewires and amount of contrast used during the index procedure were smaller in the PRA group. The incidence of procedure‐related adverse events was not significantly different between the two groups.
Conclusions
PRA showed higher procedural efficiency than RRA with comparable safety. Opting for PRA for complex CTOs might be a rational decision to enhance the procedural efficiency.
Comparative outcomes of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) for left main coronary artery (LMCA) disease were previously reported. However, data on ...very long-term (>10 years) outcomes are limited.
The authors compare 10-year outcomes after PCI and CABG for LMCA disease.
In this observational study of the MAIN-COMPARE (Revascularization for Unprotected Left Main Coronary Artery Stenosis: Comparison of Percutaneous Coronary Angioplasty versus Surgical Revascularization) registry, the authors evaluated 2,240 patients with unprotected LMCA disease who underwent PCI (n = 1,102) or underwent CABG (n = 1,138) between January 2000 and June 2006. Adverse outcomes (death; a composite outcome of death, Q-wave myocardial infarction, or stroke; and target-vessel revascularization) were compared with the use of propensity scores and inverse-probability-weighting adjustment. The follow-up was extended to at least 10 years of all patients (median 12.0 years).
In the overall cohort, there was no significant difference in adjusted risks of death and the composite outcome between the groups up to 10 years. The risk of target-vessel revascularization was significantly higher in the PCI group. In the cohort comparing drug-eluting stents and concurrent CABG, the 2 study groups did not differ significantly in the risks of death and the composite outcome at 5 years. However, after 5 years, drug-eluting stents were associated with higher risks of death (hazard ratio: 1.35; 95% confidence interval: 1.00 to 1.81) and the composite outcome (hazard ratio: 1.46; 95% confidence interval: 1.10 to 1.94) compared with CABG.
In patients with significant LMCA disease, as compared with CABG, PCI showed similar rates of death and serious composite outcomes, but a higher rate of target-vessel revascularization at 10 years. However, CABG showed lower mortality and serious composite outcome rates compared with PCI with drug-eluting stents after 5 years. (Revascularization for Unprotected Left Main Coronary Artery Stenosis: Comparison of Percutaneous Coronary Angioplasty versus Surgical Revascularization MAIN-COMPARE; NCT02791412)
Display omitted
Objectives This study aimed to validate the SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score representing angiographic complexity after unprotected left main coronary artery (ULMCA) ...revascularization. Background The validity of the SYNTAX score has been adequately evaluated. Methods The SYNTAX scores were calculated for 1,580 patients in a large multicenter registry who underwent percutaneous coronary intervention (PCI) (n = 819) or coronary artery bypass graft (CABG) (n = 761) for ULMCA stenosis. The outcomes of interests were 3-year incidences of major adverse vascular events (MAVE), including death, Q-wave myocardial infarction, and stroke and major adverse cardiac and cerebrovascular events (MACCE), including MAVE and target vessel revascularization of ULMCA. Results The incidence of 3-year MAVE was 6.2% in the lowest (≤23), 7.1% in the intermediate (23 to ∼36), and 17.4% in the highest (>36) SYNTAX score tertile groups after PCI (p = 0.010). However, the incidences of MAVE in the CABG group and MACCE in the PCI and CABG groups did not differ among the SYNTAX tertiles. In subgroups, the MAVE (p = 0.005) and MACCE (p = 0.007) rates according to the SYNTAX score tertiles were significantly different in patients receiving drug-eluting stent, not in those receiving bare-metal stent. When compared with the clinical EuroSCORE (European System for Cardiac Operative Risk Evaluation), the C-indexes of SYNTAX score and EuroSCORE were 0.59 and 0.67, respectively, for discrimination of MAVE and 0.53 and 0.57, respectively, for MACCE. Conclusions The angiographic SYNTAX score seems to play a partial role in predicting long-term adverse events after PCI for ULMCA stenosis. A complementary consideration of patient's clinical risk might improve the predictive ability of risk score.
Despite concerns regarding the long-term safety of drug-eluting stent (DES) implantation because of late-onset stent thrombosis, the actual incidence of stent thrombosis after 1 year is unknown. We ...investigated the incidence, risk factors, and association of antiplatelet therapy interruption for the development of stent thrombosis after DES implantation during long-term follow-up. A total of 1,911 consecutive patients with DES implantation were enrolled (sirolimus-eluting stents in 1,545 patients, 2,045 lesions; paclitaxel-eluting stents in 366 patients, 563 lesions). During long-term follow-up (median 19.4 months, interquartile range 15.3 to 24.3), 15 patients (0.8%, 95% confidence interval 0.5% to 1.3%) developed stent thrombosis within 6 hours to 20.4 months. Eleven patients (0.6%, 95% confidence interval 0.3% to 1.0%) had late thrombosis (median 6.1 months). The incidence of stent thrombosis was 3.3% (4 of 121 patients) in patients with complete interruption of antiplatelet therapy (vs 0.6% in those without, p = 0.004) and 7.8% (5 of 64 patients) with premature interruption of aspirin or clopidogrel, or both (vs 0.5% in those without, p <0.001). Independent predictors of stent thrombosis were premature antiplatelet therapy interruption, primary stenting in acute myocardial infarction, and total stent length. Stent thrombosis also developed while patients were on dual antiplatelet therapy (all patients with acute/subacute stent thrombosis and 36% of those with late stent thrombosis; 47% of total with stent thrombosis). In conclusion, stent thrombosis occurred in 0.8% after DES implantation during long-term follow-up. The incidence of late stent thrombosis was 0.6%, similar to that for bare metal stents. The predictors of stent thrombosis were premature antiplatelet therapy interruption, primary stenting in acute myocardial infarction, and total stent length.
An easily peelable coating was prepared using silane-terminated polyurethane dispersions (SPUDs) and UiO-66 catalyst (a zirconium(IV)-based metal–organic framework), to capture and decompose the ...nerve agent simulant, methyl paraoxon (MPO), at room temperature. SPUDs were used as the binder. The peel strength of the SPUD film containing UiO-66 decreased with increasing UiO-66 content, and the film with 40 wt% UiO-66 could not be easily peeled off. In contrast, the SPUD/PVB/UiO-66 peelable coating film could be easily peeled off. With increasing UiO-66 content, the Young’s moduli of the SPUD/UiO-66 and SPUD/PVB/UiO-66 coating films gradually increased, while the elongation decreased. The increase in the glass transition temperature was less than approximately 5%, depending on the UiO-66 content of the SPUD/UiO-66 film. Two peaks of tan δ appeared for the SPUD/PVB/UiO-66 coating film. As the UiO-66 content increased, the second peak shifted to the right. This could be attributed to the bond strength between the mixed polymeric binder and the nanoparticles. Furthermore, MPO decomposition by the SPUD/PVB/UiO-66 coating film increased with increasing UiO-66 content. These findings suggest the possibility of the development of a peelable coating film for the capture and decomposition of MPO.
We performed the long-term follow-up of a large cohort of patients in a multicenter study receiving left main coronary artery (LMCA) revascularization.
Limited information is available on long-term ...outcomes for patients with unprotected LMCA disease who underwent coronary stent procedure or coronary artery bypass grafting (CABG).
We evaluated 2,240 patients with unprotected LMCA disease who received coronary stents (n = 1,102; 318 with bare-metal stents and 784 with drug-eluting stents) or underwent CABG (n = 1,138) between 2000 and 2006 and for whom complete follow-up data were available for at least 3 to 9 years (median 5.2 years). The 5-year adverse outcomes (death; a composite outcome of death, Q-wave myocardial infarction MI, or stroke; and target vessel revascularization TVR) were compared with the use of the inverse probability of treatment weighted method and propensity-score matching.
After adjustment for differences in baseline risk factors with the inverse probability of treatment weighting, the 5-year risk of death (hazard ratio HR: 1.13; 95% confidence interval CI: 0.88 to 1.44, p = 0.35) and the combined risk of death, Q-wave MI, or stroke (HR: 1.07; 95% CI: 0.84 to 1.37, p = 0.59) were not significantly different for patients undergoing stenting versus CABG. The risk of TVR was significantly higher in the stenting group than in the CABG group (HR: 5.11; 95% CI: 3.52 to 7.42, p < 0.001). Similar results were obtained in comparisons of bare-metal stent with concurrent CABG and of drug-eluting stent with concurrent CABG. In further analysis with propensity-score matching, overall findings were consistent.
During 5-year follow-up, stenting showed similar rates of mortality and of the composite of death, Q-wave MI, or stroke but higher rates of TVR as compared with CABG for patients with unprotected LMCA disease.
The aim of the present study was to assess the intravascular ultrasound predictors for angiographic edge restenosis after newer generation drug-eluting stent implantation. A total of 820 patients ...(987 lesions) who underwent newer generation drug-eluting stent placement (236 Endeavor zotarolimus-eluting stents, 246 Resolute zotarolimus-eluting stents, and 505 everolimus-eluting stents) with 9 months of angiographic surveillance were enrolled. The post-stenting angiographic and intravascular ultrasound images of 1,668 reference segments (681 proximal and 987 distal) were analyzed. Overall, 37% of angiographically normal proximal reference segments and 21% of angiographically normal distal reference segments had plaque burden >50%. In the overall cohort of 1,668 reference segments, 47 (2.8%) had 9-month angiographic edge restenosis (diameter stenosis >50%). Edge restenosis was predicted by a post-stenting reference segment plaque burden >54.5% (sensitivity 81%, specificity 80%) and a reference segment minimum lumen area of 5.7 mm2 (sensitivity 72%, specificity 59%). The edge restenosis rate was 2.1% in the Endeavor zotarolimus-eluting stents, 2.4% in the Resolute zotarolimus-eluting stents, and 3.4% in the everolimus-eluting stents lesions (p = 0.311). The predictive cutoff of the reference plaque burden was 56.3% for Endeavor zotarolimus-eluting stents, 57.3% for Resolute zotarolimus-eluting stents, and 54.2% for everolimus-eluting stents. The criteria for residual plaque burden were similar between proximal and distal reference segments (56.4% vs 51.9%, respectively), but the minimum lumen area criteria were quite different (<7.1 mm2 for proximal vs <4.8 mm2 for distal reference segments). In conclusion, after newer drug-eluting stent implantation, edge restenosis was predicted by post-stenting reference segment plaque burden >55%.
Poly (Lactic-co-Glycolic Acid) (PLGA) based bio-composites for orthopedic implants are becoming more important as surgical techniques develop. Enhancers such as hydroxyapatite (HA) are used to ...enhance the biocompatibility and bone formation. Studies on HA surface treatment have been proposed to enhance the bonding force between particles HA and PLGA. Conventional monomer-based grafting techniques have limitations in copolymer grafting and improving mechanical strength of composites. In this study, PLGA can be directly grafted to HA surface in polymer state using melt grafting with transesterification. With this method, the grafting efficiency of PLGA is improved compared to previous studies. The grafting efficiency of PLGA was analyzed and the structure at the surface was confirmed. It was confirmed that a polymer having a large molecular weight can be grafted on the HA surface when PLGA is in an abundant state by indirectly analyzing the size of the grafting polymer through molecular weight evaluation. A composite materials using PLGA-g-HA prepared under optimized conditions have tensile strengths increased by more than doubled compared with a n-HA blended composite. The direct grafting technique of polymer was found to be effective in forming the anchoring structure between HA particles and PLGA.
Display omitted
PDF
