Side Branch Research Articles

Improved physical, thermal, and biological properties of green synthesized Ag-containing nanocomposites of a novel chitosan-based blend

Different material compositions are being prepared to improve the physiochemical properties of chitosan biopolymer and thus to create new areas of use. This study presents new chitosan(CS)-based products based on synthetic polymers and biosynthesized AgNPs, prioritizing environmentally friendly synthesis methods. Methacrylate-based functional CP copolymer was prepared by the free radical polymerization method. Thanks to the amide, ester groups, and fluorine atoms in the side branch of the CP, a compatible polymer blend (CS-CP) was prepared by the environmentally friendly hydrothermal method through hydrogen bonds with CS. Again, with green synthesis applications, AgNPs were prepared from Prunus spinosa extract by hydrothermal method, and new nanocomposites were produced by adding CS-CPs at different weight ratios. The initial decomposition temperature of 245 °C, which indicates the thermal stability of CS-CP as determined by TGA, was increased to 268 °C with the addition of 7 % AgNPs. Adding CP to CS lowered the glass transition temperature, and this trend continued in nanocomposites with the addition of AgNPs. When CP was blended with CS, the oxidative stress index of CS increased from 18.26 AU to 65.45 AU. It was determined that this oxidative effect increased up to 181 AU when AgNPs were added. Thanks to this feature of the produced nanocomposites, it was found that the MIC (100–250 µg/mL for E. coli, 250–500 µg/mL for S. aureus and for 500–1000 µg/mL C. Albicans) values of CS against microorganisms decreased, and the antimicrobial activity increased. In addition, in studies with cancer (A549 and G361) cells, it was determined that even at low (25 µg/mL) doses, nanocomposites that included 5 % and 7 % AgNPs in their formula had anticarcinogenic activity. Further studies on biocompatibility may be recommended to confirm possible commercial benefits from the materials produced in future research.

Abstract 18560: External Calcium Modification Technique to Recanalize a Balloon Uncrossable Chronic Coronary Total Occlusion

Introduction: Despite improvements in equipment and techniques, uncrossable chronic total occlusion (CTO) coronary lesions remain challenging.Case: A 66-year-old male with typical angina and a history of failed CTO PCI was referred to our CTO tertiary center as he did not wish to undergo coronary artery bypass grafting. Transthoracic echocardiography revealed an ejection fraction of 45%, and cardiac MRI demonstrated viability in the LAD region. Coronary angiography revealed a long LAD CTO over 20 mm with heavy calcification (Figure 1a). The J-CTO score was calculated to be 4. The cap of the CTO was semi-ambiguous. The wire was advanced through the highly calcified lesion with the support of a microcatheter but the microcatheter and low-profile balloons were unable to be advanced despite backup with 7 French femoral access and an EBU catheter in place (Figure 1b) Upon failure on using Leopard crawl technique and grenadoplasty and with unfavorable side branch anatomy for STAR technique, cracking the calcification with a balloon advanced over a subintimal hydrophilic wire was considered. A fielder XT-A guidewire was advanced around the CTO lesion in the subintimal area (Figure 1c). A 2x12 mm balloon was inflated at 8 atm over the wire situated in the subintimal area in order the crack the calcification from outside. After extraluminal plaque modification, the wire and the balloon were withdrawn. A microcatheter was then able to be advanced with the support of an anchor balloon over the original true lumen wire (Figure 1d). Then the procedure was successfully completed with balloon dilatation and stent implantation (Figure 1e-f). Conclusion: External Calcium Modification technique which consists of plaque modification using a balloon in subintimal space (over an intentionally directed wire in subintima and around the calcium) and cracking the calcium from the outer vessel structure can be used as a last resort to overcome balloon uncrossable CTO lesions.

Two-Stage Endovascular Aneurysm Repair with Preemptive Embolization: A Retrospective Study

ObjectiveType II endoleak is the most common complication of endovascular aneurysm repair. Retrograde perfusion from the aneurysmal sac side branch to the aneurysmal sac, including the inferior mesenteric artery and lumbar arteries, is associated with adverse events after endovascular aneurysm repair, such as aneurysm sac enlargement, reintervention, rupture, and abdominal aortic aneurysm-related death. Preemptive embolization of the aneurysmal sac side branch before endovascular aneurysm repair is an effective and safe procedure for preventing type II endoleak and reducing the size of the aneurysmal sac. Since 2019, we have been conducting preemptive embolization of the inferior mesenteric artery and lumbar arteries. Thus, we intended to work on a two-stage endovascular aneurysm repair in which embolization and endovascular aneurysm repair are performed on separate days, owing to concerns about prolonged operative time and increased contrast media use and radiation exposure from performing endovascular aneurysm repair simultaneously. This study aimed to evaluate the effects of a two-stage endovascular aneurysm repair. MethodsThis retrospective study included 114 cases of endovascular aneurysm repair (95 men and 19 women) for AAA performed at our hospital between January 2019 and December 2022. Inferior mesenteric artery and lumbar artery embolization were performed simultaneously with endovascular aneurysm repair (simultaneous group) in 49 cases, and two-stage embolization was performed (two-stage group) in 30 cases. The primary endpoints included the occurrence of T2EL during follow-up and the embolization rate of the IMA or LAs. ResultsType II endoleak did not occur in the two-stage group(follow-up period;35±6.2 months), whereas it was observed in 8.2% of patients more than 6 months after EVAR in the simultaneous group(follow-up period;28±5.5months). While the total operative time was 340 ± 111.2 min in the simultaneous group, the durations for embolization and endovascular aneurysm repair in the two-stage group were 169 ± 35.5 min and 135.0 ± 26.4 min (total time 304 ± 31.2 min, p=0.21), respectively, indicating a reduction in the total time required for the two techniques. The total amounts of contrast media used in the simultaneous and two-stage groups were 200.0 ± 179.2 mL and 182.0 ± 51.2 mL(p=0.42), respectively, and the corresponding total radiation doses were 2502.4 ± 690.5 mGy and 2114.6 ± 351.2 mGy (p=0.28), respectively, showing a decrease in both in the two-stage group. The lumbar artery embolization rates were 74.3% and 87.9% (p<0.01) in the simultaneous and two-stage groups, respectively, indicating a significant difference. ConclusionsTwo-stage endovascular aneurysm repair with preemptive embolization of the inferior mesenteric artery and lumbar arteries may be an effective strategy for reducing type II endoleak occurrence, overall operative time, contrast use, and overall radiation exposure.

Multislice computerized tomography coronary angiography can be a comparable tool to intravascular ultrasound in evaluating "true" coronary artery bifurcations.

Coronary bifurcation atherosclerosis depends on its angles, flow, and extensive branching. We investigate the ability of CT coronary angiography (CTCA) to determine atherosclerotic plaque characteristics of "true" bifurcation compared with intravascular ultrasound (IVUS) and the influence on side branch (SB) fate after percutaneous coronary intervention (PCI). The study included 70 patients with 72 "true" bifurcations. Most of the bifurcations were in the left anterior descending-diagonal (Dg) territory [50 out of 72 (69.4%)]. Longitudinal plaque evaluation at the polygon of confluence [carina and 5 mm proximal and distal in the main branch (MB)] showed that carina side MB and SB plaque had occurred with the lowest incidence with fibro-lipid structure (115 ± 63 HU and 89 ± 73 HU, p < 0.001 for all). Bland-Altman analysis showed a discrepancy in measuring mainly the lumen area between CTCA and IVUS in proximal MB [lumen 5.10, 95% CI (95% confidence interval, 4.53-5.68) mm2, p < 0.001; vessel -1.42, 95% CI (-2.63 to -0.21) mm2, p = 0.023], carina MB [lumen 3.74, 95% CI (3.37-4.10) mm2, p < 0.001; vessel -0.48, 95% CI (-1.45 to 0.48) mm2, p = 0.322], and distal MB [lumen 4.72, 95% CI (4.27-5.18) mm2, p < 0.001; vessel 0.62, 95% CI (-0.53 to 1.77) mm2, p = 0.283]. A significant correlation existed between average plaque density on CTCA with a percentage of calcified plaque on IVUS tissue characterization (proximal r = 0.307/p = 0.024, carina 0.469/0.008, distal 0.339/0.024, minimal lumen diameter 0.318/0.020). Circumferential plaque in the proximal MB segment remained an independent predictor of SB compromise [OR 3.962 (95% CI 1.170-13.418)]. Detection and characterization of atherosclerotic plaque by CTCA in non-left main "true" coronary bifurcations can provide useful information about bifurcation anatomy and plaque distribution that can predict outcomes after provisional stenting, thus guiding the interventional strategy to bifurcation PCI.

Multi-scale dynamic fusion for correcting uneven illumination images

Images taken under non-ideal lighting conditions often suffer from uneven illumination, resulting in image distortion and unclear details. To address these issues, researchers have developed various methods for image enhancement. However, most of these methods are only applicable to specific types of images, especially those with underexposed exposures. Therefore, to achieve this goal, in this article, we propose a multi-scale dynamic fusion method for correcting uneven illumination images. This method can balance the overall illumination of unevenly illuminated images captured under non-ideal lighting conditions, while maintaining the original brightness contrast and enhancing the image details. We constructed a multi-branch multi-scale fully convolutional neural network, which uses attention mechanisms to focus on the bright and dark areas that need to be processed in the main branch, while the side branch is used to maintain the image’s color and naturalness. Extracting features at different scales is beneficial for detail recovery, while a larger receptive field results in better brightness contrast and a more realistic visual experience. Finally, the attention fusion method is used to fuse the features of different branches to obtain the corrected results.

Early experience with the Gore TAG thoracic branch endoprosthesis for treatment of acute aortic pathology

The Gore TAG thoracic branch endoprosthesis (TBE) is the first Food and Drug Administration–approved device for zone 2 thoracic endovascular aortic repair, allowing for graft placement proximal to the left subclavian artery origin and maintaining vessel patency through a side branch. We describe our experience with the Gore TBE device in 20 patients for acute indications, including blunt thoracic aortic injuries, complicated dissections, and ruptured aneurysms. Technical success, with exclusion of pathology and left subclavian patency, was 100% without major complications within 30 days. Our early Gore TBE device experience demonstrates safe use in acute aortic pathology without an increased risk of complications.

Investigating the Globally Collapsing Hub–Filament Cloud G326.611+0.811

We present a dynamics study toward the G326.611+0.811 (G326) hub–filament system (HFS) cloud using new APEX observations of both 13CO and C18O (J = 2–1). The G326 HFS cloud constitutes a central hub and at least four hub-composing filaments that are divided into a major branch of filaments (F1 and F2) and a side branch (F3–F5). The cloud holds ongoing high-mass star formation as characterized by three massive dense clumps (i.e., 370–1100 M ⊙ and 0.14–0.16 g cm−2 for C1–C3) with high clump-averaged mass infalling rates (>10−3 M ⊙ yr−1) within the major filament branch, and the associated point sources bright at 70 μm, typical of young protostars. Along the five filaments, velocity gradients are found in both 13CO and C18O (J = 2–1) emission, suggesting that filament-aligned gravitational collapse toward the central hub (i.e., C2) is responsible for the high-mass star formation therein. Moreover, a periodic velocity oscillation along the major filament branch is revealed in both 13CO and C18O (J = 2–1) emission with a characteristic wavelength of ∼3.5 pc and an amplitude of ∼0.31–0.38 km s−1. We suggest that this pattern of velocity oscillation in G326 could arise from clump-forming gas motion induced by gravitational instabilities. The prevalent velocity gradients, fragmentation of the major branch of filaments, and the ongoing collapse of the three massive dense clumps are indicative that G326 is an HFS undergoing global collapse.

Outcomes of Provisional Stenting With Versus Without Side Branch Intervention in Patients With Bifurcation Lesion–Related ST-Segment Elevation Myocardial Infarction

To date, the best approach to coronary bifurcation lesion remains unsettled, and the parameters to guide side branch ballooning or stenting are not yet defined. This study aimed to compare the survival outcomes after provisional stenting with versus without side branch intervention. A cohort was conducted on 132 patients who underwent coronary angiography at Toulouse University Hospital for ST-segment elevation myocardial infarction with large culprit nonleft main coronary bifurcation lesion. Study participants were divided into 2 groups depending on the performance or not of a side branch intervention. We observed the living status at 1-year after hospital discharge. Side branch intervention by balloon inflation or final balloon kissing technique was performed in 34.1% of study participants. At 1-year follow-up, the incidence of all-cause mortality was 7.8 per 100 person-years (95% confidence interval [CI] 4.1 to 15), and although it seemed higher in the side branch intervention group (10 per 100 person-years [95% CI 3.8 to 26.7] vs 6.6 per 100 persons-years [95% CI 2.8 to 15.9]), the survival analyses showed no differences in survival outcomes (hazard ratio side branch intervention 1.55 [0.42 to 5.78], p=0.513). In conclusion, in the setting of a coronary bifurcation causing ST-segment elevation myocardial infarction, simple provisional stenting without side branch intervention showed a low mortality rate and no differences in the 1-year survival outcomes.

PROCESSING OF WELLHEAD CHRISTMAS TREES PIPE HEADER

In this study, the components of the tubing head of the Wellhead Christmas tree are classified. Information on how to install the tubing head to the Christmas tree (oil and gas) is also provided. The tested tubing head ensures the passage of liquid or gas into the spaces between the tubes. They have to control the pressure and conduct the necessary well studies. The tubing header seals and hangs the riser columns, which is especially effective when inserting concentric or parallel columns into the well. As a result of the conducted studies, the tubing head fully controls the flow of the technological liquid. Tubing headers to perform these processes should be manufactured according to the working pressure requirements between 14 and 105 MPa. Using a tubing head, you can connect different numbers of pipelines, as well as control the distribution of the medium flow in the circular zone of the valve. Of the cost-effective methods we have mentioned one is connected to the upper flange of the pipeline column header with a lower mounting fixing component. The design of the tubing head is completed by threaded holes in the body through which you can quickly replace the side valves in the head tube. The tubing head is designed to stop one or more rows of riser (pump and compressor) tubes and is used to perform technological operations during the development, operation and repair of wells. The top of the tubing at the wellhead is screwed into the tubing cap of the Christmas tree (oil and gas). Once installed at the wellhead, the Christmas tree (oil and gas) tubing header is compressed to the allowable pressure for pressure testing the production casing. Tubing head design and strength characteristics are shown in this figure: a) working pressure (7, 14.21, 35, 70 and 105 MPa), b) numbers of pipes lowered into the well (one and two concentric rows of pipes), c) constructions of locking devices (valves and taps) dimensions of the flow section along the trunk (50... 150 mm) and side branches (50... 100 mm). The tubing head holds and takes over the pressure generated between the tubes and can be prohibitive, which is quite dangerous for people's lives and health. Keywords: Christmas tree (oil and gas), tubing header, pressure, flow, wellhead, test, well.

Flow-diverter stents in intracranial aneurysm treatment: impact on covered cerebral artery branches.

Flow diverter stents (FDSs) have attracted interest for intracranial aneurysm (IA) treatment; however, occlusion of side branches and related complications have been reported. This study aimed to investigate the effects of FDSs in IA management when different branches of intracranial arteries are covered. A cross-sectional study was conducted using PUBMED, Embase, Web of Science, and Cochrane databases to include randomized or nonrandomized comparative-designed studies from January 2000 to August 2022 which reported outcomes of occlusion/narrowing of branches after IA treatment using FDSs. The PRISMA guidelines were used for our report. A random-effects meta-analysis was conducted to pool the outcomes, which included incidence rates of occlusion/narrowing of FDS-covered branches, branch occlusion-related symptoms, obliteration of IAs, and ideal clinical outcomes (modified Rankin Scale score ≤2). The authors identified 57 studies involving 3789 patients with IA managed by FDSs covering different branches. During the median imaging follow-up at 12 months, the IA obliteration rate was satisfactory (>70%) when covering the ophthalmic artery (OA), posterior communicating artery (PComA), anterior choroidal artery (AChoA) or anterior cerebral artery (ACA), but not the middle cerebral artery-M2 segment (MCA-M2; 69.5%; 95% CI: 60.8-77.5%) and posterior inferior cerebellar artery (PICA; 59.1%, 13/22). The overall ideal clinical outcome was observed in 97.4% of patients (95% CI: 95.5-98.9%). Higher rates of occlusion/narrowing of branches were identified when FDSs covered the ACA (66.6%; 95% CI: 45.1-85.3%), PComA (44.3%; 95% CI: 34.2-54.6%), or MCA-M2 (39.2%; 95% CI: 24.5-54.7%); the risks were lower when covering the OA (11.8%; 95% CI: 8.8-15.1%), PICA (6.8%; 95% CI: 1.5-14.5%), and AchoA (0.5%; 95% CI: 0.0-2.9%). The risk of branch occlusion-related complications was low (incidence rate <5%) for each of the six evaluated branches. Acceptable outcomes were identified following treatment of IAs when FDSs were placed across each of the six studied cerebral arteries. Treatment decisions regarding FDS placement across branch arteries should be made with the risk of complications from branch occlusion in mind.

Safety and efficacy of braided stents as stent monotherapy for the treatment of small intracranial aneurysms.

The safety and efficacy of low-profile braided stent as stent monotherapy require further investigation. To analyze patient outcomes after treatment with braided stents used as "light" flow diverters. Retrospective study to evaluate the occlusion rate of aneurysms treated with braided stent and remodeling of covered side branches and perforators. Several factors potentially influencing aneurysm occlusion were analyzed. Thirty-five aneurysms in 31 patients were included. Six aneurysms (17.1%) had an acute subarachnoid hemorrhage. Braided stent was used as retreatment among 9 previously coiled aneurysms (25.7%). A total occlusion was achieved in 18 aneurysms (51.4%), entry remnant in 3 aneurysms (8.6%), incomplete filling in 6 aneurysms (17.1%) and complete filling in 8 aneurysms (22.9%). None of the aneurysms ruptured during the follow-up period. Of 32 stents deployed, we observed 3 cases (9.4%) of asymptomatic mild stenosis and 3 cases (10.7%) of narrowing of covered branches among 28 covered arteries. There were no cases of perforator infarction and no mortality or permanent morbidity associated with the treatment. Moreover, aneurysms <2.5 mm, aneurysms with a neck <1.8 mm, those with a mean aspect-ratio of 1.4, and lateral wall aneurysms had a higher frequency of adequate occlusion. Braided stents used as stent monotherapy appear to be sufficiently effective in the treatment of very small intracranial aneurysms, despite a lower overall occlusion rate compared to a standard flow diversion strategy. However, given the low morbidity rate, this strategy may be an alternative to flow-diverter stents for small and distally located lesions.

Pre-dilation with a Scoring Balloon on Small Side Branch Occlusions During Long Coronary Stent Implantation

Pre-dilation with a Scoring Balloon on Small Side Branch Occlusions During Long Coronary Stent Implantation

Mitigating the risk of flow deterioration by deferring stent optimization in STEMI patients with large thrombus burden: Insights from a prospective cohort study

ObjectivesIt is uncertain, if omitting post-dilatation and stent oversizing (stent optimization) is safe and may decrease the risk for distal thrombus embolization (DTE) in STEMI patients with large thrombus burden (LTB).BackgroundIn patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) with stenting, (DTE) and flow deterioration are common and increase infarct size leading to worse outcomes.MethodsFrom a prospective registry, 74 consecutive STEMI patients with LTB undergoing pPCI with stenting and intentionally deferred stent optimization were analyzed. Imaging data and outcomes up to 2 years follow-up were analyzed.ResultsOverall, 74 patients (18% females) underwent deferred stent optimization. Direct stenting was performed in 13 (18%) patients. No major complications occurred during pPCI. Staged stent optimization was performed after a median of 4 (interquartile range (IQR) 3; 7) days. On optical coherence tomography, under-expansion and residual thrombus were present in 59 (80%) and 27 (36%) cases, respectively. During deferred stent optimization, we encountered no case of flow deterioration (slow or no-reflow) or side branch occlusion. Minimal lumen area (mm2) and stent expansion (%) were corrected from 4.87±1.86mm to 6.82±2.36mm (p<0.05) and from 69±18% to 91±12% (p<0.001), respectively. During follow-up, 1 patient (1.4%) required target lesion revascularization and 1 (1.4%) patient succumbed from cardiovascular death.ConclusionsAmong STEMI patients with LTB, deferring stent optimization in the setting of pPCI appears safe and potentially mitigates the risk of DTE. The impact of this approach on infarct size and clinical outcomes warrants further investigation in a dedicated trial.

Twenty-five-year trends in incidence, angiographic appearance, and management of spontaneous coronary artery dissection

BackgroundSpontaneous coronary artery dissection (SCAD) has been described as an infrequent cause of acute coronary syndrome (ACS). Knowledge about the disease is still limited and SCAD might still be underdiagnosed. ObjectivesTrends in incidence, presentation, angiographic appearance, management, and outcomes of SCAD over 25 years were analyzed. MethodsPatients with SCAD between 1997 and 2021 at the University Hospital Zurich, Switzerland, were included. Incidences were assessed as total numbers and proportions of ACS cases. Clinical data were collected from medical records and angiographic findings were reviewed. Major adverse cardiac events (MACE) were defined as the composite of all-cause death, cardiac arrest, SCAD recurrence or progression, other myocardial infarction, and stroke. ResultsOne hundred fifty-six SCAD cases were included in this study. The incidence increased significantly in total (p < 0.001) and relative to ACS cases (p < 0.001). This was based on an increase of shorter lesions (p = 0.004), SCAD type 2 (p < 0.001), and lesions in side branches (p = 0.014), whereas lesions in the left main coronary artery and proximal segments were decreasing (p-values 0.029 and < 0.001, respectively). There was an increase in conservative therapy (p < 0.001). The rate of MACE (24%) was stable, however, there was a reduced proportion of patients with a need for intensive care treatment (p = 0.017). ConclusionsSCAD represents an important entity of ACS that still might be underappreciated. The increasing incidence of SCAD is likely based on better awareness and familiarity with the disease. A lower need for intensive care treatment suggests positive effects of the increasing implementation of conservative management.

Bifurcation PCI with a hybrid strategy with drug- eluting balloons versus a stepwise provisional two- stent strategy: Rationale and design of the hybrid DEB study

The Hybrid DEB study is a prospective, multicenter, randomized controlled trial investigating noninferiority of a hybrid DEB approach, using a combination of a drug-eluting stent (DES) in the main vessel and DEB in the side branch, compared to stepwise provisional two-stent strategy in patients with true bifurcation lesions. A total of 500 patients with de novo true coronary bifurcation lesions, treated with a stepwise provisional approach and an unsatisfactory result of the side branch after main vessel stenting (≥ 70% stenosis and/or < thrombolysis in myocardial infarction III flow), will be randomized in a 1:1 ratio to receive either treatment with a DEB or with a DES in the side branch. The primary endpoint is a composite endpoint of the occurrence of all-cause death, periprocedural or spontaneous myocardial infarction and/or target vessel revascularization at the anticipated median 2-year follow-up. The Hybrid DEB study will compare in a multicenter, randomized fashion a hybrid DEB approach with a stepwise provisional two-stent strategy in patients with true bifurcation lesions. ClinicalTrials.gov no. NCT05731687.

Experiência inicial com a extensão de cateter-guia ExpressmanTM em um centro terciário de cardiologia de alto volume

Background: Guide catheter extensions provide increased support in complex percutaneous coronary interventions. The ExpressmanTM is a novel guide catheter extension and the objective was to assess the impact of its use on procedural success and complications in a high-volume reference center. Methods: We analyzed data from all consecutive procedures in which the ExpressmanTM guide catheter extension was used. The decision to use a guide catheter extension was at operator’s discretion. Device success was defined as the successful positioning of the guide catheter extension in the coronary vessel and procedural success was defined as &lt;20% residual stenosis and TIMI 3 flow, with no loss of significant side branches. Major adverse cardiac and cerebrovascular events were defined as the composite of all-cause death, myocardial infarction, target vessel revascularization and stroke. Results: From April 2022 to January 2023, 34 procedures were included. The majority of the patients were male (59%) and the mean age was 66.5 years. Guide catheter extension use was not planned pre-procedure in 17 procedures (50%). The most common reasons for guide catheter extension use were target vessel angulation or tortuosity and unfavorable coronary ostium position. Device success was obtained in 88% and revascularization success in 91%. There were three side branch occlusions. During in-hospital clinical follow-up, no major adverse cardiac and cerebrovascular events or major bleeding occurred. Conclusion: The device success and procedural success were high and the rate of complications was low. Guide catheter extension use as bailout technique in complex anatomies allowed procedural success in the vast majority of otherwise untreatable patients.

Como cruzar lesões intransponíveis na oclusão crônica

Coronary chronic total occlusion occurred in approximately 15 to 20% of patients. The most common challenges associated with successful percutaneous coronary intervention in chronic total occlusion are undilatable and uncrossable lesions. Uncrossable lesions are characterized as those lesions in which the balloon cannot cross the lesion. These types of lesions are commonly seen in calcified and tortuous arteries, and in chronic total occlusion. Various techniques, such as side branch anchoring, rotational, orbital, or laser atherectomy can be used to treat these challenging lesions. In this article, we describe the tips and tricks which can be commonly used to cross uncrossable lesions.

Paraclinoid internal carotid artery aneurysm with delayed stent occlusion after deployment of a flow diverter stent involving the orifice of the anterior cerebral artery: illustrative case.

In-stent thrombotic occlusion is a serious ischemic complication that can also result in ischemia in the distal perfusion territory and the territory of side branches for the artery in which the flow diverter (FD) stent is deployed. A 49-year-old female with a large paraclinoid internal carotid artery (ICA) aneurysm was treated with an FD involving the orifice of the anterior cerebral artery (ACA). The antiplatelet dose was reduced because of an increased clopidogrel response postintervention. The patient developed aphasia 2 months later. Emergency magnetic resonance imaging and digital subtraction angiography of the brain indicated FD stent occlusion and a small infarct in the distal vascular territory of the ipsilateral ICA, but the anterior choroidal artery (AChoA) territory was preserved by collateral flow. Emergency superficial temporal artery to middle cerebral artery anastomosis was performed, and she was discharged without neurological deficit 2 weeks after the second operation. In-stent occlusion after FD deployment involving the orifice of the ACA can cause severe cerebral ischemia that requires an adequate antiplatelet effect and careful follow-up. The AChoA territory can be preserved by collateral blood flow even in cases of in-stent occlusion.

Impact of coronary bifurcation angle on stent malapposition in a randomized comparison between proximal optimization technique followed by side branch dilatation and kissing balloon inflation.

The impact of coronary bifurcation angle (BA) on incomplete stent apposition (ISA) after crossover stenting followed by side branch (SB) intervention has not been established. A total of 100 crossover stentings randomly treated with proximal optimization technique followed by short balloon dilation in the SB (POT-SBD group, 48 patients) and final kissing balloon technique (KBT group, 52 patients) were analyzed in the PROPOT trial. Major ISA with maximum distance>400μm and its location was determined using optical coherence tomography before SB intervention and at the final procedure. The BA was defined as the angle between the distal main vessel and SB. Optimal POT was determined when the difference in stent volume index between the proximal and distal bifurcation was greater than the median value (0.86mm3/mm) before SB intervention. Major ISA was more frequently observed in the POT-SBD than in the KBT group (35% versus 17%, p<0.05). In the POT-SBD group, worsening ISA after SBD was prominent at the distal bifurcation. The BA was an independent predictor of major ISA (odds ratio 1.04, 95% confidence interval 1.00-1.07, p<0.05) with a cut-off value of 59.5° (p<0.05). However, the cases treated with optimal POT in the short BA (<60°) indicated the lowest incidence of major ISA. In the KBT group, BA had no significant impact. A wide BA has a potential risk for the occurrence of major ISA after POT followed by SBD in coronary bifurcation stenting.

Transformer With Double Enhancement for Low-Dose CT Denoising.

Increasingly serious health problems have made the usage of computed tomography surge. Therefore, algorithms for processing CT images are becoming more and more abundant. These algorithms can lessen the harm of cumulative radiation in CT technology for the patient while eliminating the noise of image caused by dose reduction. However, the mainstream CNN-based algorithms are inefficient when dealing with features in broad regions. Inspired by the large receptive field of transformer framework, this paper designs an end-to-end low-dose CT (LDCT) denoising network based on the transformer. The overall framework of network contains a main branch and dual side branches. Specifically, the overlapping-free window-based self-attention transformer block is adopted on the main branch to realize image denoising. On the dual side branches, we propose double enhancement module to enrich edge, texture, and context information of LDCT images. Meanwhile, the receptive field of network is further enlarged after processing, which is helpful for building model's long-range dependencies. The outputs of the side branches are concatenated to the middle layer of the network for enhancing information and generating high-quality CT images. In addition, to better train the network and achieve the expected results, we introduce a compound loss function including mean squared error (MSE), multi-scale perceptual (MSP), and Sobel-L1 (SL) to make the denoised image closer to the targeted norm-dose CT (NDCT) image. Lastly, we conducted experiments on two clinical datasets including abdomen, head, and chest LDCT images with 25%, 25%, and 10% of the full dose, respectively. The experimental results demonstrated that the proposed DEformer achieved better denoising performance than the existing algorithms.