Synchrotron microtomography reveals insights into the degradation kinetics of bio-degradable coronary magnesium scaffolds

Bioresorbable magnesium scaffolds are a promising future treatment option for coronary artery stenosis, especially for young adults. Due to the degradation of these scaffolds (<1 year), long-term device-related clinical events could be reduced compared to treatments with conventional drug eluting stents. First clinical trials indicate a return of vasomotion after one year, which may be associated with improved long-term clinical outcomes. However, even after decades of development, the degradation process, ideal degradation time and biological response in vivo are still not fully understood. The present study investigates the in vivo degradation of magnesium scaffolds in the coronary arteries of pigs influenced by different strut thicknesses and the presence of antiproliferative drugs. Due to high 3D image contrast of synchrotron-based micro-CT with phase contrast (SR-μCT), a qualitative and quantitative evaluation of the degradation morphology of magnesium scaffolds was obtained. For the segmentation of the μCT images a convolutional network architecture (U-net) was exploited, demonstrating the huge potential of merging high resolution SR-μCT with deep learning (DL) supported data analysis. In total, 30 scaffolds, made of the rare earth alloy Resoloy®, with different strut designs were implanted into the coronary arteries of 10 domestic pigs for 28 days using drug-coated or uncoated angioplasty balloons for post-dilatation. The degradation morphology was analyzed using scanning electron microscopy, energy dispersive x-ray spectroscopy and SR-μCT. The data from these methods were then related to data from angiography, optical coherence tomography and histology. A thinner strut size (95 vs. 130 μm) and the presence of paclitaxel indicated a slower degradation rate at 28 d in vivo, which positively influences the late lumen loss (0.5 and 0.6 mm vs. 1.0 and 1.1 mm) and recoil values (0 and 1.7% vs. 6.1 and 22%).

Recurrent Revascularization at 10 Years After Percutaneous Treatment of Drug-Eluting Stent Restenosis

BACKGROUND

Treatment of patients with recurrence of in-stent restenosis (ISR) remains particularly challenging, with data and guideline recommendations for repeat percutaneous coronary intervention being scant.

OBJECTIVES

The aim of this study was to investigate the long-term incidence of recurrent revascularization events after percutaneous treatment of drug-eluting stent (DES) ISR.

METHODS

In this post hoc analysis, 402 patients (500 lesions) assigned to plain balloon (PB), drug-coated balloon (DCB), or DES treatment in the randomized ISAR-DESIRE 3 (Efficacy Study of Paclitaxel-Eluting Balloon, -Stent vs. Plain Angioplasty for Drug-Eluting Stent Restenosis) trial were followed up over a median of 10.3 years. The primary endpoint was total repeat target lesion revascularization (R-TLR) including all, first and recurrent, events.

RESULTS

At the end of follow-up, first R-TLR was required in 204 lesions, 82 in the PB group, 70 in the DCB group, and 52 in the DES group. The total number of R-TLRs was 373: 162 in the PB group, 124 in the DCB group, and 87 in the DES group. During the first year of follow-up, the risk for total R-TLR was reduced by DCB (HR: 0.36; 95% CI: 0.24-0.54) and DES (HR: 0.23; 95% CI: 0.14-0.38) treatment compared with PB treatment. After 1 year, the risk for total R-TLR was nonsignificantly reduced by DCB treatment (HR: 0.77; 95% CI: 0.51-1.16) and significantly reduced by DES treatment (HR: 0.61; 95% CI: 0.39-0.95) compared with PB treatment. Risk in the DCB and DES groups was similar during (HR: 1.54; 95% CI: 0.89-2.69) and after (HR: 1.26; 95% CI: 0.82-1.92) 1 year.

CONCLUSIONS

The total number of R-TLRs over 10 years after treatment of patients with DES ISR was high. DCBs and particularly DES were able to reduce the need for both first and recurrent revascularization compared with PB treatment.

Drug-coated balloons versus drug-eluting stents in patients with acute myocardial infarction undergoing percutaneous coronary intervention: an updated meta-analysis with trial sequential analysis

BACKGROUND

Drug-coated balloons (DCBs) are an established strategy for coronary artery disease. However, the new generation drug-eluting stent (DES) is recommended for patients with Acute myocardial infarction (AMI) for coronary artery revascularization. Our aim is to provide a comprehensive appraisal of the efficacy of DCBs in patients with AMI undergoing PCI.

METHODS

We searched the WOS, PubMed, Scopus, and Cochrane CENTRAL till March 2023, for studies that compared DCBs versus DES in patients with AMI undergoing PCI. We used a random-effects model to compare major adverse cardiac events (MACE), cardiac death, all-cause death, myocardial infarction, target lesion revascularization (TLR), stent thrombosis, Late lumen Loss (LLL), and minimum lumen diameter (MLD) between the two groups.

RESULTS

Thirteen studies comprising 2644 patients were included. The pooled OR showed non-inferiority of DCB over DES in terms of MACE (OR = 0.89, 95% CI [0.57 to 1.40], p = 0.63). When we defined MACE as a composite of cardiac death, MI, and TLR; the pooled OR favored DCB over DES (OR = 0.50, 95% CI [0.28 to 0.9], p = 0.02). Moreover, DCB was not inferior to DES in terms of all-cause mortality (OR = 0.88, 95% CI: 0.43 to 1.8, p = 0.73), cardiac mortality, (OR = 0.59, 95% CI: 0.22 to 1.56, p = 0.29), MI (OR = 0.88, 95% CI: 0.34 to 2.29, p = 0.79), stent thrombosis (OR = 1.21, 95% CI: 0.35 to 4.23, p = 0.76), TLR (OR = 0.9, 95% CI: 0.43 to 1.93, p = 0.8), LLL (MD = -0.6, 95% CI: -0.3 to 0.19, p = 0.64), or MLD (MD = -0.4, 95% CI: -0.33 to 0.25, p = 0.76).

CONCLUSION

Our meta-analysis indicated that DCB intervention was not inferior to DES in the PCI setting in patients with AMI, and can be recommended as a feasible strategy in AMI.

PROSPERO REGISTRATION

CRD42023412757.

A Systematic Review and Meta-analysis of Atherectomy Plus Balloon Angioplasty Versus Balloon Angioplasty Alone for Infrapopliteal Arterial Disease

OBJECTIVE

The article aimed to compare the efficiency and safety of atherectomy plus balloon angioplasty (BA) with BA alone for the treatment of infrapopliteal arterial disease.

METHODS

According to the inclusion and exclusion criteria, PubMed, Embase, and Cochrane Library database were searched for studies comparing atherectomy plus angioplasty and angioplasty alone in treating infrapopliteal artery lesions until November 2022. The endpoints included technical success, primary patency, clinically-driven target lesion revascularization (CD-TLR), periprocedural complications, distal embolization, target limb major amputation, and all-cause mortality.

RESULTS

Ten studies met the requirements of our meta-analysis, including 7723 patients in the atherectomy plus BA group and 2299 patients in the BA alone group. The meta-analysis showed that atherectomy plus BA was associated with reduced CD-TLR (odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.34, 0.78, p=0.002) and target limb major amputation (OR: 0.43, 95% CI: 0.19, 1.01, p=0.05) at 12-month follow-up. No statistically significant difference was found in technical success, primary patency, periprocedural complications, distal embolization, or all-cause mortality. Subgroup analysis found a higher rate of primary patency at 6 and 12 months (6 months: OR: 2.26, 95% CI: 1.11, 4.60, p=0.02; 12 months: OR: 2.38, 95% CI: 1.16, 4.86, p=0.02), and lower rates of CD-TLR (OR: 0.45, 95% CI: 0.25, 0.82, p=0.009) and target limb major amputation (OR: 0.43, 95% CI: 0.19, 1.01, p=0.05) at 12 months in patients treated with atherectomy plus drug-coated balloon (DCB) but not in patients treated with atherectomy plus plain old balloon angioplasty (POBA).

CONCLUSIONS

This meta-analysis suggests that compared with BA alone, atherectomy plus BA may reduce the need for CD-TLR and the incidence of target limb major amputation at 12-month follow-up in the treatment of infrapopliteal artery occlusive lesions, even though there are no significant advantages in technical success, primary patency, periprocedural complications, distal embolization, or all-cause mortality. To go further, atherectomy plus DCB shows significant benefits in primary patency, CD-TLR, and target limb major amputation rate but atherectomy plus POBA does not'. However, due to the limitations of this article, more randomized controlled trials (RCTs) are needed to confirm these conclusions.

CLINICAL IMPACT

According to our research, atherectomy combined with BA has the advantages of higher primary patency rate, lower CD-TLR and target limb significant amputation rate in treating infrapopliteal artery occlusive lesions, which may replace the current mainstream surgical method ---BA alone. For the clinician, although the surgery may take longer, it will significantly improve the prognosis and quality of life of patients and hold considerable significance for the management of patients with infrapopliteal arterial disease. Based on the characteristics of infrapopliteal artery disease, this study explored the feasibility of atherectomy combined with BA for infrapopliteal artery disease. Moreover, we found that atherectomy combined with DCB had better clinical efficacy, which should be the innovation of this study.

The evolution and revolution of drug coated balloons in coronary angioplasty: An up-to-date review of literature data

European Society of Cardiology (ESC) guidelines gave class I A indication for use of DCB in in-stent restenosis. However, no indication exists for the usage of DCB in de novo lesions. Although the current generation DES offer excellent results, as we embark more complex lesions such as calcified lesion and chronic total occlusion, restenosis and stent thrombosis are higher and tend to increase within the years. There is increasing desire to leave nothing behind to abolish the risk of restenosis and stent thrombosis and hence the absorbable scaffolds were introduced, but with disappointing results. In addition, they take several years to be absorbed. Drug coated balloons offer an alternative to stents with no permanent implant of metal or polymer. They are already in use in in Europe and Asia and they have been approved for the first time in the United States for clinical trials specifically for restenotic lesions. There is emerging data in de novo lesions which have shown that DCB are noninferior and in some studies maybe even superior to current generation DES especially in small vessels. In this article, we provide a comprehensive review of the literature on this expanding technology focussing on the evidence in both re-stenotic and de novo lesions.

Sirolimus-Coated Balloon in an All-Comer Population of Coronary Artery Disease Patients: The EASTBOURNE Prospective Registry

BACKGROUND

Drug-coated balloons (DCB) represent 1 of the most promising innovations in interventional cardiology and may represent a valid alternative to drug-eluting stents. Currently, some sirolimus-coated balloons (SCB) are being investigated for several coronary artery disease applications.

OBJECTIVES

This study sought to understand the role of a novel SCB for the treatment of coronary artery disease.

METHODS

EASTBOURNE (All-Comers Sirolimus-Coated Balloon European Registry) is a prospective, multicenter, investigator-driven clinical study that enrolled real-world patients treated with SCB. Primary endpoint was target lesion revascularization (TLR) at 12 months. Secondary endpoints were procedural success, myocardial infarction (MI), all-cause death, and major adverse clinical events (a composite of death, MI, and TLR). All adverse events were censored and adjudicated by an independent clinical events committee.

RESULTS

A total population of 2,123 patients (2,440 lesions) was enrolled at 38 study centers in Europe and Asia. The average age was 66.6 ± 11.3 years, and diabetic patients were 41.5%. De novo lesions (small vessels) were 56%, in-stent restenosis (ISR) 44%, and bailout stenting occurred in 7.7% of the patients. After 12 months, TLR occurred in 5.9% of the lesions, major adverse clinical events in 9.9%, and spontaneous MI in 2.4% of the patients. The rates of cardiac/all-cause death were 1.5% and 2.5%, respectively. The primary outcome occurred more frequently in the ISR cohort (10.5% vs 2.0%; risk ratio: 1.90; 95% CI: 1.13-3.19). After multivariate Cox regression model, the main determinant for occurrence of the primary endpoint was ISR (OR: 5.5; 95% CI: 3.382-8.881).

CONCLUSIONS

EASTBOURNE, the largest DCB study in the coronary field, shows the safety and efficacy of a novel SCB in a broad population of coronary artery disease including small vessels and ISR patients at mid-term follow-up. (The All-Comers Sirolimus-Coated Balloon European Registry [EASTBOURNE]; NCT03085823).

Assessment of Paclitaxel Drug-Coated Balloon Only Angioplasty in STEMI

BACKGROUND

Primary percutaneous coronary intervention (pPCI) with drug-eluting stents (DES) has emerged as the standard of care, but stent-related events have persisted. Drug-coated balloon (DCB)-only angioplasty is an emerging technology, although it is not fully evaluated compared with DES in the context of pPCI.

OBJECTIVES

The aim of this study was to investigate the safety of DCB-only angioplasty compared with second-generation DES in pPCI.

METHODS

All-cause mortality and net adverse cardiac events (cardiovascular mortality, acute coronary syndrome, ischemic stroke or transient ischemic attack, major bleeding, and unplanned target lesion revascularization [TLR]) were compared among all patients treated with DCBs only or with second-generation DES only for first presentation of ST-segment elevation myocardial infarction (STEMI) due to de novo disease between January 1, 2016, and November 15, 2019. Patients treated with both DCBs and DES were excluded. Data were analyzed using Cox regression models, Kaplan-Meier estimator plots and propensity score matching.

RESULTS

Among 1,139 patients with STEMI due to de novo disease, 452 were treated with DCBs and 687 with DES. After a median follow-up period of >3 years, all-cause mortality was 49 of 452 and 62 of 687 in the DCB and DES groups, respectively (P = 0.18). On multivariable Cox regression analysis, there was no difference in mortality between DCBs and DES in the full and propensity score-matched cohorts. Age, frailty risk, history of heart failure, and family history of ischemic heart disease remained significant independent predictors of mortality. There was no difference in any of the secondary endpoints, including unplanned TLR.

CONCLUSIONS

DCB-only angioplasty appears safe compared with DES for STEMI in terms of all-cause mortality and all net adverse cardiac events, including unplanned TLR. DCB may be an efficacious and safe alternative to DES in selected patient groups. (Drug Coated Balloon Only vs Drug Eluting Stent Angioplasty; NCT04482972).

Intravascular Lithotripsy and Drug-Coated Balloon Angioplasty for Severely Calcified Femoropopliteal Arterial Disease

INTRODUCTION

The combination of intravascular lithotripsy (IVL) and drug-coated balloon (DCB) angioplasty for calcified peripheral lesions is associated with promising short-term results. However, data regarding the 12 months performance of this treatment option is missing. This study reports on the outcomes of IVL and DCB angioplasty for calcified femoropopliteal disease.

METHODS

Patients treated with IVL and DCB for calcified femoropopliteal lesions between February 2017 and September 2020 were included into this study. The primary outcome measure of this analysis was primary patency. Secondary patency, freedom from target lesion revascularization (TLR) and overall mortality were additionally analyzed.

RESULTS

Fifty-five (n = 55) patients and 71 lesions were analyzed. Most patients presented with long-term limb-threatening ischemia (n = 31, 56%), 47% (n = 26) were diabetics, and 66% (n = 36) had long-term kidney disease. The median lesion length was 77 mm (interquartile range: 45-136), and 20% (n = 14) of the lesions were chronic total occlusions (CTOs). Eccentric calcification was found in 23% of the vessels (n = 16), and circumferential calcium (peripheral arterial calcium scoring system [PACSS] Class 3 and 4) was present in 78% (n = 55) of the treated lesions.The technical success after IVL amounted to 87% (n = 62) and the procedural success to 97% (n = 69). A flow-limiting dissection was observed in 2 cases (3%). Both the rates of target lesion perforation and distal embolization were 1% (n = 1). A bail-out scaffold was deployed in 5 lesions (7%). At 12 months the Kaplan-Meier estimate of primary patency was 81%, the freedom from TLR was 92% and the secondary patency 98%. The overall survival amounted to 89%, while the freedom from major amputation to 98%. The presence of eccentric disease, CTOs, or PACSS Class 4 did not increase the risk for loss of patency or TLR.

CONCLUSIONS

In this challenging cohort of patients, the use of IVL and DCB for calcified femoropopliteal lesions was associated with promising 12 months outcomes and an excellent safety profile.

Finite Element Analysis of Crack Propagation in Adhesive Joints with Notched Adherends

The adherends notching technique has been the subject of a few recent studies and consists of tailoring the geometry of the adjoined layers to mitigate the bondline peak stresses and enhance the joint strength. In the present study, we explored the effect of the adherends notching technique on crack propagation using finite element (FE) simulations based on the cohesive zone model (CZM) of fracture. Double cantilever beam (DCB) adhesive joints subjected to quasistatic loading were considered as a model material system. An array of equally spaced notches was placed on the faying sides of the adherends, oriented perpendicularly to the direction of crack growth. A parametric investigation was carried out to ascertain the role of the notches and the input cohesive properties on various performance metrics, e.g., load-displacement response and dissipated energy. The proposed notching strategy promotes an unstable crack pinning/depinning process, which effectively delays crack growth and increases the effective work of fracture. Additionally, we found that the overall behaviour is tunable by changing geometric (i.e., notch spacing and depth) and bondline material properties.

Drug loss from Paclitaxel-Coated Balloons During Preparation, Insertion and Inflation for Angioplasty: A Laboratory Investigation

Purpose

To investigate drug contamination of the working environment with paclitaxel drug-coated balloon (DCB) angioplasty due to loss of paclitaxel containing particles from the coating during DCB preparation, insertion, and inflation.

Material and Methods

In an experimetal laboratory setting, drug loss during removal of the protective cover and insertion of the DCB through the hemostatic valve of the introducer sheath and after inflation was examined. In seven DCB types of different manufacturers, semi-quantitative image analysis was performed during five standardized tests cycles. Additionally, every DCB type passed one cycle of a wipe test and one cycle of air sampling.

Results

By removing the protective cover, the paclitaxel-covered balloon surface was significantly reduced in 3 out of 7 products (P = 0.043). Overall, extend of decline ranged from 0.4 to 12%. In 6 of 7 products, powdered paclitaxel clusters dropped down upon removal of the protective cover (0.099 ng/cm² up to approx. 22 ng/cm²). Contamination of the air was detected in none of the DCB types. When pushed through the vascular sheath, none of the investigated DCB types showed a significant loss of paclitaxel from the coated balloon surface. After balloon inflation, the paclitaxel-coated surface area varied between manufacturers ranging from 25.9 to 97.8%.

Conclusion

In some DCB types, the removal of the protective cover already leads to a significant loss of paclitaxel and paclitaxel-coated surfaces. As a result, there will be a contamination of the workplace and a reduction in the therapeutic dose.

Level of Evidence

No level of evidence.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00270-022-03164-5.

Concomitant Drug-Coated Balloon Angioplasty With Bail-Out Use of Eluvia Drug-Eluting Stent: Is There Any Downside to a Double Dose of Paclitaxel?

OBJECTIVE

The application of 2 distinct and simultaneously applied drug-delivery platforms for the treatment of peripheral artery disease (PAD) has not been studied. This study investigated the outcomes of femoropopliteal disease treated with drug-coated balloon (DCB) followed by placement of drug-eluting stent (DES) when a bail-out procedure is required.

METHODS

This was a single-center, retrospective study enrolling 22 consecutive patients (23 limbs) treated with DCB + DES. Bail-out stenting was performed for flow-limiting postangioplasty dissections and/or suboptimal angiographic result, such as residual stenosis. Procedural success (<30% residual stenosis) and the incidence of major adverse limb event (MALE) during an average follow-up of 15.2 months were estimated.

RESULTS

Among the 22 patients (23 limbs), 14 presented with claudication and 8 with critical limb ischemia. The majority of the lesions were Trans-Atlantic Inter-Society Consensus class C/D, with a mean lesion length of 321 ± 130 mm. DCB angioplasty was performed with Stellarex (Philips) in 6 cases and In.Pact DCB (Medtronic) in 16 cases. Eluvia DES (Boston Scientific) was used for bail-out stenting in all cases (in 10 limbs for flow-limiting dissection and in 13 limbs for suboptimal angiographic result due to significant residual stenosis and/or recoil). A single Eluvia DES was used in 15 cases, while multiple Eluvia DESs were used in 8 cases. Procedural success was achieved in all but 1 case where persistent recoil occurred in a heavily calcified lesion. During an average follow-up of 15 months, restenosis or reocclusion of the target vessel was observed in 6 cases (26.1%), although only 3 patients required repeat revascularization (13.0%). During follow-up, 1 death and 1 major amputation occurred, both in patients who had originally presented with critical limb ischemia. Additionally, on routine duplex ultrasound, there were no cases of aneurysm formation at the sites of Eluvia stent placement.

CONCLUSION

DCB with provisional DES implantation could be a viable treatment option for cases of suboptimal DCB results, without apparent additional cardiovascular or limb-related risks. Additional studies are needed to determine the risks and benefits of double-dose paclitaxel approach, especially for those patients with significant residual stenosis after DCB.

Utilization of Drug-Coated Balloons for the Treatment of Coronary Lesions in the Elderly Population

Introduction: The use of drug-coated balloons (DCBs) has become more prevalent in the past few years for the treatment of in-stent restenosis (ISR) and de novo lesions. The absence of foreign polymer implantations potentially shortens the duration of dual anti-platelet therapy (DAPT), which can be beneficial for the elderly population. We aimed to investigate the safety and efficacy of the use of DCBs for the treatment of coronary lesions in elderly patients as compared to the younger population. Materials and methods: A database of 446 consecutive patients who underwent a procedure of DCB inflation in our institution was divided into two groups, below 70 years old and above 80 years old. We compared and analyzed the endpoints of total major adverse cardiovascular events (MACE), cardiovascular (CV) death, and all-cause mortality in both groups. Results: The difference in MACE between the two age groups was non-significant (p = 0.225); the difference in cardiovascular death was also non-significant (p = 0.086). All-cause mortality was significantly different (p < 0.0001) and can be attributed to the age of the patients. Conclusion: The utilization of DCBs for the treatment of coronary lesions may be as safe and effective for the elderly population as for the younger population and may allow a shorter period of DAPT therapy, which can lower the risk of bleeding.

Study on Delamination Damage of CFRP Laminates Based on Acoustic Emission and Micro Visualization

This study investigated the mechanism of delamination damage in the double cantilever beam (DCB) standard test by the use of the strain energy release rate. The curve of the strain energy release rate was verified by the Rise Angle (RA) method. For this purpose, 24-layer carbon fiber/epoxy multidirectional laminates with interface orientations of 0°, 30°, 45°, and 60° were fabricated according to the standard ASTM D5528(13). In the course of this test, acoustic emission (AE) was used for real-time monitoring, and combined with micro visualization, the damage mechanism of composite multidirectional laminates was studied at multiple scales. Combining the AE detection results with micro visualization, it is found that the AE parameters and the damage to multidirectional laminates could realize a one-to-one correspondence. Through the study of the variation of the RA value, load, and strain energy release rate with the crack length, it is proved that the AE parameters can effectively characterize the initiation of delamination damage.

Orbital Atherectomy Prior to Drug-Coated Balloon Angioplasty in Calcified Infrapopliteal Lesions: A Randomized, Multicenter Pilot Study

PURPOSE

Optimal balloon angioplasty for infrapopliteal lesions is often limited by severe calcification, which has been associated with decreased procedural success and lower long-term patency.

MATERIALS AND METHODS

This was a prospective, randomized, multicenter pilot trial that included adult subjects with calcified lesions located from the popliteal segment below the knee (BTK) joint to within 5 cm above the ankle with ≥70% diameter stenosis by angiography. Patients were randomized 1:1 to undergo orbital atherectomy (OA) with adjunctive drug-coated balloon (DCB) angioplasty versus plain balloon angioplasty (BA) and DCB angioplasty (control). The periprocedural and 12 month outcomes of both procedures were compared.

RESULTS

Overall, 66 subjects (OA + DCB = 32 vs control = 34) were included in an intention to treat analysis. Baseline demographics and lesion characteristics were well-balanced. The mean lesion length was 101.3 mm (SD = 72.8 mm) and 78.8 (SD = 61.0 mm) in the OA + DCB and control groups, respectively, with almost all lesions having severe calcification per the Peripheral Academic Research Consortium (PARC) criteria. Chronic total occlusions (CTOs) were present in 43.8% and 35.3% of the patients in the OA + DCB and control groups, respectively. The technical success of OA + DCB versus DCB was 81.8% and 89.2%, respectively, with 3 slow flow/no reflow, 1 perforation, 1 severe dissection occurred in OA + DCB group, and one distal embolization occurred in the control group. The target lesion primary patency rate was numerically higher in the OA + DCB versus control group at 6 (88.2% vs 50.0%, p=0.065) and 12 month follow-up (88.2% vs 54.5%, p=0.076). The 12 month freedom from major adverse events, clinically-driven target lesion revascularization, major amputation, and all-cause mortality rates were similar between both groups.

CONCLUSION

The results of the Orbital Vessel PreparaTIon to MaximIZe Dcb Efficacy in Calcified BTK (OPTIMIZE BTK) pilot study indicated that utilization of OA + DCB is safe for infrapopliteal disease. Further prospective adequately powered studies should investigate the potential benefit of combined OA + DCB for BTK lesions.

Effect of Drug-Coated Balloon in Side Branch Protection for de novo Coronary Bifurcation Lesions: A Systematic Review and Meta-Analysis

Background: At present, there are a variety of treatment strategies for percutaneous coronary intervention. The role of drug-coated balloon (DCB) in the treatment of side branch for de novo coronary bifurcated lesions (CBL) is unclear.

Objective: To examine the effect of DCB in side branch protection for de novo CBL.

Methods: Electronic databases, including Pubmed, Embase, the Web of science, Cochrance library, CNKI, CBM, WanFang Data and VIP were searched for studies that compared DCB with non-drug-coated balloon (NDCB) in side branch protection for de novo CBL from inception through July 7th, 2021. The primary outcome was target lesion revascularization (TLR). Secondary clinical outcomes included myocardial infarction (MI), cardiac death (CD). The angiographic outcomes included side branch late lumen loss (LLL), minimum lumen diameter (MLD), diameter stenosis (DS) and binary restenosis (BR). The target lesion failure (TLF) was also analyzed.

Results: A total of 10 studies, including 5 randomized controlled trials and 5 non-randomized observational studies, with 934 patients were included. Meta-analysis results of angiographic outcomes suggested that DCB group had the less LLL, DS and BR and the higher MLD compared with NDCB group at follow-up (P < 0.05). Meta-analysis results of clinical outcomes suggested that the significant difference in the TLR, MI and CD between DCB group and NDCB group has not been found yet (P > 0.05). However, the MACE of DCB group was significantly less than that of NDCB group at 9-month follow-up [OR = 0.21, 95%CI (0.05, 0.84), P = 0.03] and 12-month follow-up [OR = 0.45, 95%CI (0.22, 0.90), P = 0.02]. In addition, there was no significant difference in TLF between DCB group and NDCB group (P > 0.05).

Conclusions: DCB had great effect in side branch protection for de novo CBL at short and medium-term follow-up with no reduction in the procedural success rate.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=267426, PROSPERO [Identifier: CRD42021267426].

Should paclitaxel be considered an old generation DCB? The limus era

Since their introduction Drug Coated Balloons (DCBs) have slowly gained their spot into everyday cath-lab practice, first for treatment of in-stent restenosis (ISR), more recently for small vessels disease; today a growing body of evidence start supporting their use in more complex lesions, from bifurcations, to large vessels, to acute lesions. Although the new generation of DCBs showed a better performance and safety than the older one, the drug of choice has always been the Paclitaxel; last year some concerns were raised on the safety of Paclitaxel devices, in particular the balloons mining their use. Recently Sirolimus ventured in the DCBs world, making its appearance on cath-lab shelves and becoming a good alternative to Paclitaxel (DCB).

Paclitaxel Drug-Coated Balloon for the Treatment of De Novo Small-Vessel and Restenotic Coronary Artery Lesions: 12-Month Results of the Prospective, Multicenter, Single-Arm PREVAIL Study

OBJECTIVES

The PREVAIL study evaluated the safety and effectiveness of a paclitaxel-coated percutaneous transluminal coronary angioplasty balloon catheter for the treatment of coronary de novo and in-stent restenosis (ISR) lesions in patients with symptomatic ischemic heart disease.

METHODS

PREVAIL was a prospective, multicenter, single-arm study that enrolled patients with clinical evidence of ischemia who had coronary lesions (de novo or first ISR) amenable to treatment with a drug-coated balloon (DCB). The study included 50 subjects (53 target lesions) who were treated with a Prevail DCB (Medtronic) during the index procedure and followed for 12 months. Mean lesion length was 14.5 ± 7.6 mm. The primary endpoint was in-stent (in-balloon) late lumen loss (LLL) by quantitative coronary angiography at 6 months post procedure. If the mean in-stent (in-balloon) LLL was less than the maximum acceptance rate of 0.50 mm at 6 months, then the study was considered successful.

RESULTS

Mean in-stent (in-balloon) LLL was 0.05 ± 0.44 mm at 6 months post procedure. There were no deaths, myocardial infarctions, or stent (lesion) thrombosis events within 12 months. The incidence of clinically driven target-lesion revascularization was 6.0% at 12 months and clinically driven target-vessel revascularization was 10.0%.

CONCLUSIONS

Paclitaxel DCB treatment of coronary de novo and first ISR lesions led to low LLL at 6 months and low rates of revascularization and safety events through 12 months.

Comparison of Clinical Outcomes With Drug Coated Balloons Versus Plain Balloon Angioplasty In Chronic Limb-Threatening Ischemia

OBJECTIVE

The use of drug coated balloon (DCB) for angioplasty has shown superior efficacy against plain balloons for treating complex infrainguinal arterial disease. We report and compare the clinical outcomes following application of DCB(Paclitaxel) and plain angioplasty (POBA) in our tertiary care centre.

METHODS

A retrospective, single centre analysis of 301 patients with chronic limb-threatening ischemia involving the infrainguinal segment was conducted between September 2014 and September 2018, after approval from the Institutional review board. We analyzed clinical outcomes by measuring postoperative ABI improvement, restenosis requiring reintervention procedure, minor and major amputations at the end of 18 months. . To find the association between the group variables (POBA and DCB) and other risk variables, Chi-square test/Fisher's exact test was used. Multivariable logistic regression analysis was used.

RESULTS

Patients who underwent treatment with plain balloon (POBA) and DCB(Paclitaxel) angioplasty were 246(81.7%) and 55(18.3%) respectively. Our study group was predominantly male (Male: Female = 6.7:1), most patients were more than 50 years of age (n = 251, 83.4%). Smoking (n = 199, 66.1%) and diabetes (n = 210, 69.8%) were the most common atherosclerotic risk factors. Postoperative Ankle Brachial Pressure Index (ABI) improvement were similar in both groups (POBA = 57.7%; DCB = 69.8%; p = 0.103). Minor and major amputations following POBA were 26% and 22%; and DCB were 12.7% and 16.4% respectively. Re-stenosis requiring a re-interventional procedure within 18 months was 15%, (n = 37) following POBA; and 12.7% (n = 7) following DCB (p = 0.661).

CONCLUSIONS

This retrospective study shows similar clinical limb related outcomes following POBA and DCB at 18 months. However, our comparative analysis between the POBA and DCB groups was totally unadjusted and not adjusted for common confounders such as age and sex. Hence, for one to draw definitive conclusions leading to changes in clinical practice; a randomized, prospective study with a larger patient cohort is needed.

Outcomes with drug-coated balloons vs. drug-eluting stents in small-vessel coronary artery disease

BACKGROUND

The use of drug-coated balloons (DCBs) in small-vessel coronary artery disease (SVD) remains controversial.

METHODS

We performed a meta-analysis of all randomized controlled trials (RCTs) reporting the outcomes of DCB vs. DES in de-novo SVD. We included a total of 5 RCTs (1459 patients), with (DCB n = 734 and DES n = 725).

RESULTS

Over a median follow-up duration of 6 months, DCB was associated with smaller late lumen loss (LLL) compared with DES (mean difference -0.12 mm) (95% confidence intervals (CI) [-0.21, -0.03 mm], p = 0.01). Over a median follow-up of 12 months, both modalities had similar risk of major adverse cardiovascular events (MACE) (8.7% vs. 10.2%; odds ratio (OR): 0.94, 95% CI [0.49-1.79], p = 084), all-cause mortality (1.17% vs. 2.38%; OR: 0.53, 95% CI [0.16-1.75], p = 0.30), target lesion revascularization (TLR) (7.9% vs. 3.9%; OR: 1.26, 95% CI [0.51-3.14], p = 0.62), and target vessel revascularization (TVR) (8.2% vs. 7.8%; OR: 1.06, 95% CI [0.40-2.82], p = 0.91). DCBs were associated with lower risk of myocardial infarction (MI) compared with DES (1.55% vs. 3.31%; OR: 0.48, 95% CI [0.23-1.00], p = 0.05, I2 = 0%).

CONCLUSION

PCI of SVD with DCBs is associated with smaller LLL, lower risk of MI, and similar risk of MACE, death, TLR, and TVR compared with DES over one year. DCB appears as an attractive alternative to DES in patients with de-novo SVD, but long-term clinical data are still needed.

Impact of optimal preparation before drug-coated balloon dilatation for de novo lesion in patients with coronary artery disease

BACKGROUND

Drug eluting stent (DES) remain several problems, including stent thrombosis, stent fracture and neoatherosclerosis. Stent-less Percutaneous coronary intervention (PCI) using a drug coated balloon (DCB) is a stent-less strategy, and several trials have supported the efficacy of DCB. However, the optimal preparation before using DCB was uncertain. The aim of this study was to investigate the optimal preparation for plaque oppression/debulking before DCB dilatation for de novo coronary artery lesion.

METHODS

A total 936 patients were treated using DCB from 2014 to 2017 at our institution. Among them, we analyzed 247 patients who underwent PCI using DCB alone for de novo lesion. The primary end point of this study was target lesion failure (TLF).

RESULTS

The area under the receiver operating characteristic (ROC) curve (AUC) was used to determine the optimal cutoff value of % plaque area to predict TLF. ROC curve analysis revealed plaque area ≥ 58.5% (AUC, 0.81) were associated with TLF. Eligible 188 patients were divided into 2 groups (plaque area ≥ 58.5% [n = 38] and <58.5% [n = 150]) according to IVUS data before using DCB. TLF was significantly higher in plaque area ≥ 58.5% group than in <58.5% group (P < 0.01). Multivariable analysis selected plaque area ≥ 58.5% as an independent predictor of TLF (hazard ratio 7.59, P < 0.01).

CONCLUSIONS

Lesion preparation achieving plaque area < 58.5% was important in stent-less PCI using DCB.

Paclitaxel exposure: Long-term safety and effectiveness of a drug-coated balloon for claudication in pooled randomized trials

BACKGROUND

Paclitaxel drug-coated balloons (DCB) prevent recurrent claudication after angioplasty, yet data from randomized trials with incomplete follow-up have raised uncertainty regarding long-term mortality.

OBJECTIVES

To evaluate the effect of paclitaxel exposure on the long-term safety and efficacy of angioplasty of femoropopliteal artery lesions in the combined IN.PACT randomized trials.

METHODS

The IN.PACT randomized trials (SFA, N = 331 and Japan, N = 100) each compared the DCB with standard percutaneous transluminal angioplasty (PTA) for claudication, and consented patients for 5 and 3 years, respectively. To address long-term safety, sites were requested to obtain vital status follow-up. In the pooled, updated data set, we examined the association between randomized treatment and mortality by cumulative incidence and hazard ratio (HR), and freedom from clinically driven target lesion revascularization (CD-TLR). Multivariable Cox regression with adjustment for baseline characteristics was used to evaluate the dose effect. Causes of death were adjudicated by a blinded clinical events committee that included oncologists with paclitaxel expertise.

RESULTS

The rate of long-term vital status ascertainment increased from 81% to 97% for DCB and from 85% to 97% for PTA in the IN.PACT SFA trial. The cumulative incidence of mortality was 14.7% DCB versus 12.0% PTA at 5 years, HR 1.39, log-rank p = .286. Paclitaxel dose (mg) was not an independent predictor of mortality (HR 1.02, p = .381), but was an independent predictor of reduced risk of CD-TLR (HR 0.79; p < .001). Causes of death did not differ by treatment arm.

CONCLUSIONS

In pooled randomized trial data with updated vital status ascertainment, paclitaxel was associated with improved efficacy but was not associated with increased mortality.

Drug-coated balloon versus drug-eluting stent for treating de novo coronary lesions in large vessels: a meta-analysis of clinical trials

BACKGROUND

Studies examining the efficiency of drug-coated balloon (DCB) compared to drug-eluting stents (DES) for de novo lesions in large vessels have reported inconsistent results.

OBJECTIVE

This comprehensive meta-analysis of clinical trials compared the efficacy and safety of DCB and DES for the treatment of de novo coronary lesions.

METHODS

The authors formally searched electronic databases before October 2019 to identify randomized and non-randomized clinical trials (RCTs and non-RCTs, respectively). Clinical trials were eligible for inclusion if they compared DCB with DES in patients with coronary lumen diameters >2.5 mm.

RESULTS

Three RCTs and one non-RCT with a total of 321 patients were included in our meta-analysis (DCB group = 152, DES group = 169). The primary endpoint was in-segment late lumen loss (LLL) with a standardized mean difference (SMD) of -0.07 (95% confidence interval [CI]: -0.31, 0.316; P = 0.548) and the secondary endpoint was target lesion revascularization (TLR) with a risk ratio (RR) of 1.17 (95% CI: 0.46, 2.95; P = 0.746).

CONCLUSION

This meta-analysis indicated that DCB might be non-inferior to DES as evidenced by quantitative coronary angiography (QCA) assessed at 6-9 months after percutaneous coronary intervention in patients presenting with coronary artery disease.

POT-sideDCB-POT: A novel technique for treating coronary bifurcation lesions

The rePOT technique is a novel and easily applied approach for coronary bifurcations. Drug-Coated Balloon (DCB) angioplasty is increasingly being utilized in management of small vessels and coronary bifurcation lesions. Herein, we propose a new approach for treating coronary bifurcation lesions with the application of DCB to treat the side-branch in addition to the rePOT technique: the POT-sideDCB-POT technique.

Comparative 12-Month Outcomes of Drug-Coated Balloon Versus Non-Drug-Coated Balloon Revascularization Strategy in Chronic Limb-Threatening Ischemia: Results From the XLPAD Registry

BACKGROUND

Endovascular therapy is often the preferred first treatment option for chronic limb threatening ischemia (CLTI) patients. Drug coated balloons (DCB) reduce restenosis rates compared to percutaneous transluminal angioplasty (PTA), however DCB use has not been studied systematically in patients with CLTI. Thus, the optimal treatment option for these complex lesions remains controversial.

METHODS

We report on 327 patients with CLTI treated either with DCB (n = 105) or non-DCB (n = 222) for femoropopliteal disease. Data were retrieved from the Excellence in Peripheral Artery Disease (XLPAD) registry (NCT01904851). Two DCB types were used at the discretion of the operator: Lutonix® (BARD Peripheral Vascular, Inc., Tempe, AZ, USA) and IN.PACT AdmiralTM (Medtronic, Santa Rosa, CA, USA). Odds ratios and the respective 95% confidence interval were synthesized to examine the association between the two groups in terms of all-cause mortality, target limb repeat endovascular or surgical revascularization, target vessel revascularization (TVR), major and minor amputation at 12 months of follow up.

RESULTS

The mean lesion length was 150.0 mm (SD:123.2) and 151.2 mm (SD:108.3) for the DCB and non-DCB group respectively. No difference between the two groups was detected in terms of all-cause mortality (2.86%vs2.7%,p = .94), target limb repeat endovascular or surgical revascularization (16.19%vs12.61%,p = .25), TVR (16.19%vs.11.71%,p = .26) or minor amputation (15.24%vs10.81%,p = .25) at 12 months of follow up. Although a higher incidence of 12 months major amputation was observed in the DCB group (11%vs.4%,p = .01), after adjusting for several risk factors the odds of major amputation were not statistically different between the DCB and non-DCB groups (OR:1.54;95%CI:0.53-4.51;p = .43).

CONCLUSIONS

Both DCB and non-DCB strategies are effective modalities for revascularization of patients with CLTI. No differences were identified between the DCB and non-DCB group in terms of late outcomes during 12 months of follow up.

Turbo-Power™ Laser Atherectomy Combined with Drug-coated Balloon Angioplasty is Associated with Improved One-Year Outcomes for the Treatment of Tosaka II and III Femoropopliteal In-stent Restenosis

BACKGROUND

Femoropopliteal (FP) artery in-stent restenosis (ISR) is associated with high rates of re-intervention and occlusion. The combined use of laser atherectomy (LA) with balloon angioplasty (BA) is superior to conventional balloon angioplasty (BA). Drug-coated balloons (DCBs) when combined with LA have provided additional efficacy for the treatment of FP-ISR. The aim of this study was to investigate the combination of DCB + LA with the recently approved Turbo-Power™ (Spectranetics Inc., Colorado Springs, CO, USA) LA device.

METHODS

This was a dual-center retrospective study enrolling 78 consecutive patients with Tosaka type II (n = 18) or III (n = 60) FP-ISR. The lesions were treated with either Turbo-Power™ LA followed by DCB (n = 27) or with other LA devices followed by plain BA (LA + BA; n = 51) from 2015 to 2017. A Cox regression analysis was performed to examine the association between the two groups in terms of target lesion revascularization (TLR) and occlusion rates over a follow up period of 12 months. Kaplan-Meier survival curves were estimated and compared with the log-rank test.

RESULTS

The overall procedural success was 90%. Eight periprocedural complications occurred without any difference between the two groups (Turbo-Power™ + DCB: 7.4% vs LA + BA: 11.8%, p = .7). The 12-month KM estimates for freedom from TLR were 90.9% in the Turbo-Power™ + DCB group vs 55.7% in the LA + BA group (p = .005). Among Toasaka III lesions, the 12 m-KM survival estimates for freedom from TLR were 88.9% in the Turbo-Power™ + DCB group vs 54.2% in the LA + BA group (p = .009). The 12 m-KM estimates for freedom from re-occlusion were 89.0% in the Turbo-Power™ + DCB group vs 58.9% in the LA + BA group (p = .070).

CONCLUSIONS

Turbo-Power™ laser atherectomy combined with DCB exerted synergistic mechanism of actions and improved 12-month TLR rates for the treatment of complex FP-ISR lesions.

Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part II: Numerical Analysis

The paper deals with numerical analysis of double cantilever beam (DCB) predefined to Mode I Interlaminar Fracture Tests of GRFP unidirectional laminates. The numerical analyses were performed in the ANSYS^® program based on the finite element. In geometrically nonlinear analysis, two algorithms, responsible for initiation and propagation of delamination front, were applied: Virtual Crack Closure Technique (VCCT) and Cohesive zone method (CZM). Due to the unidirectional arrangement of layers of the laminate, the problem of DCB test was solved with the use of one- and three-dimensional models with the implementation of linear interface element and contact element. The present study highlights the limitations of existing formulae used to reliably reflect the behavior of DCB. The use of three-dimensional models allowed confirming the curved shape of the delamination front observed in experimental studies. The application of the VCCT in the three-dimensional model led to an underestimation of the global response (force-opening displacement curve) recorded during numerical DCB test.

Bayesian Network Modelling of ATC Complexity Metrics for Future SESAR Demand and Capacity Balance Solutions

Demand & Capacity Management solutions are key SESAR (Single European Sky ATM Research) research projects to adapt future airspace to the expected high air traffic growth in a Trajectory Based Operations (TBO) environment. These solutions rely on processes, methods and metrics regarding the complexity assessment of traffic flows. However, current complexity methodologies and metrics do not properly take into account the impact of trajectories’ uncertainty to the quality of complexity predictions of air traffic demand. This paper proposes the development of several Bayesian network (BN) models to identify the impacts of TBO uncertainties to the quality of the predictions of complexity of air traffic demand for two particular Demand Capacity Balance (DCB) solutions developed by SESAR 2020, i.e., Dynamic Airspace Configuration (DAC) and Flight Centric Air Traffic Control (FCA). In total, seven BN models are elicited covering each concept at different time horizons. The models allow evaluating the influence of the “complexity generators” in the “complexity metrics”. Moreover, when the required level for the uncertainty of complexity is set, the networks allow identifying by how much uncertainty of the input variables should improve.

Real-Time Global Ionospheric Map and Its Application in Single-Frequency Positioning

The prevalence of real-time, low-cost, single-frequency, decimeter-level positioning has increased with the development of global navigation satellite systems (GNSSs). Ionospheric delay accounts for most errors in real-time single-frequency GNSS positioning. To eliminate ionospheric interference in real-time single-frequency precise point positioning (RT-SF-PPP), global ionospheric vertical total electron content (VTEC) product is designed in the next stage of the International GNSS Service (IGS) real-time service (RTS). In this study, real-time generation of a global ionospheric map (GIM) based on IGS RTS is proposed and assessed. There are three crucial steps in the process of generating a real-time global ionospheric map (RTGIM): estimating station differential code bias (DCB) using the precise point positioning (PPP) method, deriving slant total electron content (STEC) from PPP with raw observations, and modeling global vertical total electron content (VTEC). Experiments were carried out to validate the algorithm’s effectiveness. First, one month’s data from 16 globally distributed IGS stations were used to validate the performance of DCB estimation with the PPP method. Second, 30 IGS stations were used to verify the accuracy of static PPP with raw observations. Third, the modeling of residuals was assessed in high and quiet ionospheric activity periods. Afterwards, the quality of RTGIM products was assessed from two aspects: (1) comparison with the Center for Orbit Determination in Europe (CODE) global ionospheric map (GIM) products and (2) determination of the performance of RT-SF-PPP with the RTGIM. Experimental results show that DCB estimation using the PPP method can realize an average accuracy of 0.2 ns; static PPP with raw observations can achieve an accuracy of 0.7, 1.2, and 2.1 cm in the north, east, and up components, respectively. The average standard deviations (STDs) of the model residuals are 2.07 and 2.17 TEC units (TECU) for moderate and high ionospheric activity periods. Moreover, the average root-mean-square (RMS) error of RTGIM products is 2.4 TECU for the one-month moderate ionospheric period. Nevertheless, for the high ionospheric period, the RMS is greater than the RMS in the moderate period. A sub-meter-level horizontal accuracy and meter-level vertical accuracy can be achieved when the RTGIM is employed in RT-SF-PPP.

Effect of 2, 6-Dichlorobenzonitrile on Amoebicidal Activity of Multipurpose Contact Lens Disinfecting Solutions

Multipurpose contact lens disinfecting solutions (MPDS) are widely used to cleanse and disinfect microorganisms. However, disinfection efficacy of these MPDS against Acanthamoeba cyst remain insufficient. 2, 6-dichlorobenzonitrile (DCB), a cellulose synthesis inhibitor, is capable of increasing the amoebical effect against Acanthamoeba by inhibiting its encystation. In this study, we investigated the possibility of DCB as a disinfecting agent to improve the amoebicidal activity of MPDS against Acanthamoeba cyst. Eight commercial MPDS (from a to h) were assessed, all of which displayed insufficient amoebicidal activity against the mature cysts. Solution e, f, and h showed strong amoebicidal effect on the immature cysts. Amoebicidal efficacy against mature cysts remained inadequate even when the 8 MPDS were combined with 100 μM DCB. However, 4 kinds of MPDS (solution d, e, f, and h) including 100 μM DCB demonstrated strong amoebicidal activity against the immature cysts. The amoebicidal activity of solution d was increased by addition of DCB. Cytotoxicity was absent in human corneal epithelial cells treated with either DCB or mixture of DCB with MPDS. These results suggested that DCB can enhance the amoebicical activity of MPDS against Acanthamoeba immature cyst in vitro.

Treatment of coronary bifurcation lesions: current knowledge and future perspectives

Coronary lesions at bifurcation sites are frequent and still remain a challenging subset for the interventional cardiologist. Although in the last years the provisional stenting technique has shown more consistent results, coronary bifurcation interventions still share a worse procedural success rate and increased rates of mid- and long-term cardiac events. Most of the dedicated devices proposed in the last few years have failed to show improved results when compared with standard devices. The broader use of imaging techniques, such as intravascular ultrasound and optical coherence tomography, lead to a better understanding of the real anatomy of bifurcations and has shown to be a great tool for percutaneous coronary intervention optimization. Preliminary results come from drug-coated balloons and bioresorbable vascular scaffolds, especially for the 'leave nothing behind' concept, particularly interesting in this setting of lesions.

Measuring the adherence energy of the resin-metal interface with two fracture mechanics methods: The DCB and NTP tests

OBJECTIVE

To evaluate the abilities of the DCB and the NTP test for measuring adherence of an adhesive joint between a resin and a metal interface.

METHODS

Two-hundred stainless steel metal beams (diam. 50×5×2 mm) were cast and treated by the following methods: (1) sandblasting with aluminum oxide, followed by treatment with (2) the Rocatec system or (3) the Alloy primer. Superbond and Panavia F 2.0 were used as adhesives. The fracture energy (G1C) and fracture toughness (K1C) of two adhesives were compared by two-way analysis of variance.

RESULTS

With the DCB test, Superbond was more effective than Panavia, regardless of the surface treatment and conditions of crack propagation. The overall effectiveness of the treatments was in the following order: sandblasting + Rocatec > sandblasting alone > sandblasting + Alloy primer. The adherence energy in an aqueous medium was lower than that in air. With the NTP test, similar performances were obtained with three surface treatments. However, the potential of Rocatec seemed slightly higher.

CONCLUSIONS

The DCB and NTP tests provide independent measures of the inherent value of an adhesive. Rocatec appeared to provide greater resistance of the bonded joints in an aqueous environment.

Ectopic lignification in primary cellulose-deficient cell walls of maize cell suspension cultures

Maize (Zea mays L.) suspension-cultured cells with up to 70% less cellulose were obtained by stepwise habituation to dichlobenil (DCB), a cellulose biosynthesis inhibitor. Cellulose deficiency was accompanied by marked changes in cell wall matrix polysaccharides and phenolics as revealed by Fourier transform infrared (FTIR) spectroscopy. Cell wall compositional analysis indicated that the cellulose-deficient cell walls showed an enhancement of highly branched and cross-linked arabinoxylans, as well as an increased content in ferulic acid, diferulates and p-coumaric acid, and the presence of a polymer that stained positive for phloroglucinol. In accordance with this, cellulose-deficient cell walls showed a fivefold increase in Klason-type lignin. Thioacidolysis/GC-MS analysis of cellulose-deficient cell walls indicated the presence of a lignin-like polymer with a Syringyl/Guaiacyl ratio of 1.45, which differed from the sensu stricto stress-related lignin that arose in response to short-term DCB-treatments. Gene expression analysis of these cells indicated an overexpression of genes specific for the biosynthesis of monolignol units of lignin. A study of stress signaling pathways revealed an overexpression of some of the jasmonate signaling pathway genes, which might trigger ectopic lignification in response to cell wall integrity disruptions. In summary, the structural plasticity of primary cell walls is proven, since a lignification process is possible in response to cellulose impoverishment.

Formation of iron plaque on mangrove Kandalar. Obovata (S.L.) root surfaces and its role in cadmium uptake and translocation

In this study, a pot experiment was conducted to investigate the formation of iron plaque under Cd stress and its role in Cd uptake and translocation by mangrove Kandalar. Obovata (S.L.). Results showed: 1. the Fe in dithionite–citrate–bicarbonate (DCB) extracts increased with an increasing rate of Cd treatments. 2. the Cd in DCB extracts and in roots and above-ground tissues significantly increased with an increasing Cd application; 3. significant positive correlation between concentration of Cd and Fe in DCB extracts existed (p < 0.05); and that 4. the proportion of Cd in DCB extracts was significantly lower than that in roots or above-ground tissues (p < 0.001). In conclusion, formation of Fe plaque can precipitate Cd on root surfaces and impede its uptake and translocation in Kandalar. Obovata (S.L.). However, in comparison with root tissues, Fe plaque is of little significance. It is the mangrove root tissue that acts as the main buffer to Cd uptake and translocation.

Chemical genetics to examine cellulose biosynthesis

Long-term efforts to decode plant cellulose biosynthesis via molecular genetics and biochemical strategies are being enhanced by the ever-expanding scale of omics technologies. An alternative approach to consider are the prospects for inducing change in plant metabolism using exogenously supplied chemical ligands. Cellulose biosynthesis inhibitors (CBIs) have been identified among known herbicides, during diverse combinatorial chemical libraries screens, and natural chemical screens from microbial agents. In this review, we summarize the current knowledge of the inhibitory effects of CBIs and further group them by how they influence fluorescently tagged cellulose synthase A proteins. Additional attention is paid to the continuing development of the CBI toolbox to explore the cell biology and genetic mechanisms underpinning effector molecule activity.