Vessel Compliance Research Articles

Legal Review of Ship Certification After the Issuance of Law Number 11 of 2020 Concerning Job Creation

This research examines the shift in authority and processes related to the certification of fishing vessels in Indonesia after the enactment of Law No. 11 of 2020 on Job Creation. The primary objective of this study is to analyze the legal force and implications of the transfer of authority from the Ministry of Transportation to the Ministry of Marine Affairs and Fisheries (KKP) in issuing fish vessel certifications. Using a normative juridical approach, this study investigates the procedural changes, challenges, and impacts of the new regulatory framework on fishing vessel safety and compliance. The findings show that the Job Creation Law simplifies licensing procedures while ensuring the safety and seaworthiness of fishing vessels. However, the study also highlights the challenges posed by a shortage of qualified inspectors, leading to delays in the certification process. This research underscores the need for regulatory adjustments and additional inspector training to align the maritime sector with the law’s goal of promoting safety and business efficiency.

Intravascular Lithotripsy: Approach to Advanced Calcified Coronary Artery Lesions, Current Understanding, and What Could Possibly Be Studied Next.

Calcified and resistant narrowing of arteries poses significant difficulty in performing percutaneous coronary interventions (PCIs), as they increase the risk of subpar outcomes leading to worse clinical outcomes. Despite the existence of dedicated technologies and devices, including various balloons and atherectomy systems, they often do not ensure sufficient plaque modification and ideal vessel preparation for optimal stent deployment. Intravascular lithotripsy (IVL), a technology originally developed for urological procedures, has recently been used to safely and selectively disrupt calcified depositions in both peripheral and coronary arteries by sonic waves that seamlessly transfer to nearby tissue, enhancing vessel compliance with minimal impact on soft tissues. In the coronary arteries, the use of IVL plays a role in the process of "vessel preparation" before the placement of stents, which is crucial for restoring blood flow in patients with severe coronary artery disease (CAD), and is considered a minimally invasive technique, reducing the need for open heart surgeries and associated risks and complications. Studies have shown that IVL can lead to improved procedural success rates and favorable long-term outcomes for patients with severely calcified coronary artery disease. With the advent of IVL, the disruption of severe calcification of coronary artery and stenotic lesions before stent implantations can be performed. Despite promising data for treating calcified lesions, IVL is significantly underutilized in clinical practice, long-term clinical data and extensive research are needed to validate its further safety and efficacy. In this article, we reviewed the literature discussing the use of IVL in the coronary arteries as an approach for addressing intravascular atherosclerotic plaques, particularly focusing on heavily calcified plaques that are resistant to standard initial PCI, while also evaluating its safety in comparison to alternative methods.

Dissecting contributions of pulmonary arterial remodeling to right ventricular afterload in pulmonary hypertension.

Pulmonary hypertension (PH) is defined as an elevation in the right ventricle (RV) afterload, characterized by increased hemodynamic pressure in the main pulmonary artery (PA). Elevations in RV afterload increase RV wall stress, resulting in RV remodeling and potentially RV failure. From a biomechanical standpoint, the primary drivers for RV afterload elevations include increases in pulmonary vascular resistance (PVR) in the distal vasculature and decreases in vessel compliance in the proximal PA. However, the individual contributions of the various vascular remodeling events toward the progression of PA pressure elevations and altered vascular hemodynamics remain elusive. In this study, we used a subject-specific one-dimensional (1D) fluid-structure interaction (FSI) model to investigate the alteration of pulmonary hemodynamics in PH and to quantify the contributions of vascular stiffening and increased resistance towards increased main pulmonary artery (MPA) pressure. We used a combination of subject-specific hemodynamic measurements, ex-vivo mechanical testing of arterial tissue specimens, and ex-vivo X-ray micro-tomography imaging to develop the 1D-FSI model and dissect the contribution of PA remodeling events towards alterations in the MPA pressure waveform. Both the amplitude and pulsatility of the MPA pressure waveform were analyzed. Our results indicated that increased distal resistance has the greatest effect on the increase in maximum MPA pressure, while increased stiffness caused significant elevations in the characteristic impedance. The method presented in this study will serve as an essential step toward understanding the complex interplay between PA remodeling events that leads to the most severe adverse effect on RV dysfunction.

Muticomponent Melt‐Electrowritten Vascular Graft to Mimic and Guide Regeneration of Small Diameter Blood Vessels

AbstractCardiovascular disease is a leading cause of morbidity. Current treatments include vessel substitution using autologous/synthetic vascular grafts, but these commonly fail in small diameter applications, largely due to compliance mismatch and clot formation. In this study, a multicomponent vascular graft, that takes inspiration from native vessel architecture, is developed to overcome these limitations. Melt electrowriting (MEW) is used to produce tubular scaffolds with vascular‐mimetic fiber architecture and mechanics, which is combined with a lyophilized fibrinogen matrix with tailored degradation kinetics to generate a hybrid graft. The MEW framework not only contributes to graft mechanics, but also provides contact guidance to direct cell/neotissue orientation and mimic the native tunica media. This construct is further functionalized with heparin, which in combination with the smooth extracellular matrix (ECM) surface, reduced platelet adhesion and clot formation providing a substrate for endothelization, thereby mimicking the function of the intima. Lastly, an outer electrospun layer representing the adventitia is added to improve elasticity and reduce permeability. This graft satisfies ISO implantability requirements, matches the compliance of native vessels, and reestablishes physiological flow with minimal clot formation in a preclinical model. Therefore, this graft represents an innovative off‐the‐shelf alternative to address the unmet clinical need for small‐diameter vascular grafts.

Effective analysis of remote ship inspection in Asia-Pacific region and its impact on shipping trade under COVID-19

ABSTRACT In the wake of the COVID-19 pandemic, the global shipping industry has faced unprecedented challenges, necessitating rapid adaptations in regulatory practices and inspection methodologies to ensure the continuity of trade and maritime safety. Remote port state control (PSC) involves the use of technology to monitor, regulate, and manage the activities and compliance of vessels in a port’s jurisdiction without the need for physical boarding or inspection. This study examines the effectiveness of remote PSC inspections within the Asia-Pacific region and assesses their impact on shipping trade during the pandemic. Utilizing a comprehensive analysis of data from remote inspections conducted under the auspices of the Tokyo Memorandum of Understanding (MOU), this research identifies key factors influencing the efficacy of such inspections and their implications for regulatory compliance and maritime safety. Through a methodological blend of quantitative analysis and qualitative evaluation, the study explores how remote inspections have been critical in maintaining operational integrity and safety standards amidst global disruptions. The findings highlight the role of the International Maritime Organization (IMO) in facilitating these adaptations, alongside the challenges and opportunities of remote inspection practices. This research contributes to the ongoing maritime safety and regulation discourse, offering insights into the potential for remote inspections to complement traditional methods in a post-pandemic world.

Optical coherence tomography imaging for the evaluation and treatment of calcified coronary artery disease

Coronary calcific disease represents one of the main challenges for the interventional cardiologist, for whom optimal lesion preparation and percutaneous coronary intervention optimization are paramount for correct management. In this perspective, intravascular imaging using optical coherence tomography (OCT) is becoming an increasingly indispensable tool. This work aims to provide a detailed overview of the complexity of calcified lesions, first analyzing their various morphologies and their clinical impact: spotty calcium seems to be more present in plaques at higher risk of destabilization, while diffuse calcification is typical of stable coronary stenosis; the eruptive calcific nodule is one of the three culprit lesion phenotypes responsible for acute coronary syndromes.In the second part of this review, the available technologies for the treatment of calcified lesions are described, with the aid of illustrative OCT images. Intravascular lithotripsy causes fractures at various levels of the calcified plaque, both circumferentially and longitudinally, with an improvement in vessel compliance; atherectomy acts by modifying the composition of the plaque with selective action on the hard calcific component. OCT, providing a comprehensive overview of lesion characteristics, can guide in the selection of the most appropriate therapeutic strategy, while also offering important information on the effectiveness of the chosen treatment.

A multi-objective optimisation approach for the linear modelling of cerebral autoregulation system

Objective:Dynamic cerebral autoregulation (dCA) has been addressed through different approaches for discriminating between normal and impaired conditions based on spontaneous fluctuations in arterial blood pressure (ABP) and cerebral blood flow (CF). This work presents a novel multi-objective optimisation (MO) approach for finding good configurations of a cerebrovascular resistance-compliance model. Methods:Data from twenty-nine subjects under normo and hypercapnic (5% CO2 in air) conditions was used. Cerebrovascular resistance and vessel compliance models with ABP as input and CF velocity as output were fitted using a MO approach, considering fitting Pearson’s correlation and error. Results:MO approach finds better model configurations than the single-objective (SO) approach, especially for hypercapnic conditions. In addition, the Pareto-optimal front from the multi-objective approach enables new information on dCA, reflecting a higher contribution of myogenic mechanism for explaining dCA impairment.

Effects of Coronary Stenosis on Coronary Vascular Impedance

Introduction: The impedance analysis for circulation system is a powerful tool to comprehensively measure the afterload of the entire circulation system. The spectrum of vascular mechanical parameters derived from the impedance analysis can reveal the compliance and resistance changes in proximal and distal vessels, as well as the wave reflections. However, the similar investigation in the opposition of the coronary circulation is limited, and it is unknown how coronary stenosis affects the vascular impedance of the coronary circulation. In this study, we aimed to quantify and compare the changes in the vascular impedance of coronary circulation from the dynamic pressure and flow relations in healthy and patients with stenosis. Method: The pressure and flow rate waveforms from the main coronary artery were obtained from a lumped-parameter computational model that coupled the systemic circulation with the coronary perfusion within a closed system. Both healthy and diseased (coronary stenosis) pressure-flow relations were examined. A Fourier transform was performed to analyze the pressure and flow data, and the resistance (Z0), characteristic impedance (ZC), wave reflections (RW), total arterial compliance (C), and other hemodynamic parameters were derived. Results: Compared to the healthy subject, the diseased subject presented an increased resistance (Z0 was elevated from 0.44 mmHg ▪ min/ml to 0.59 mmHg ▪ min/ml), increased characteristic impedance (ZC was elevated from 0.07 mmHg ▪ min/ml to 0.14 mmHg ▪ min/ml), and reduced wave reflection (RW was decreased from 0.72 to 0.6). These changes indicate elevated distal arteries and arterioles narrowing and proximal artery stiffening in the entire coronary vasculature. Moreover, the coronary flow and the total arterial compliance (stroke volume divided by pulse pressure) were reduced with the disease progression. These data suggest a reduced coronary perfusion and stiffening of the artery in the coronary circulation. Discussion: The impedance analysis has been widely used for systemic and pulmonary circulations previously to quantify the total afterload of the left and right ventricles, respectively. The distribution of the impedance in different frequencies reflects the anatomical and mechanical properties of the vasculature in the circulation system. This study originally found that the coronary artery impedance is altered by coronary stenosis. The key characteristics include the narrowing of distal coronary arteries and stiffening of proximal coronary arteries. However, since both proximal and distal arteries are altered, the wave reflection was reduced, and this may explain a reduced pulse pressure observed in the diseased subject. The reduction in overall coronary perfusion indicates an impaired blood supply to the ventricle and may be responsible for the dysfunction of the heart. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Quantifying Inferior Vena Cava Compliance and Distensibility in an In Vivo Ovine Model Using 3D Angiography.

Synthetic vascular grafts overcome some challenges of allografts, autografts, and xenografts but are often more rigid and less compliant than the native vessel into which they are implanted. Compliance matching with the native vessel is emerging as a key property for graft success. The current gold standard for assessing vessel compliance involves the vessel's excision and ex vivo biaxial mechanical testing. We developed an in vivo method to assess venous compliance and distensibility that better reflects natural physiology and takes into consideration the impact of a pressure change caused by flowing blood and by any morphologic changes present. This method is designed as a survival procedure, facilitating longitudinal studies while potentially reducing the need for animal use. Our method involves injecting a 20 mL/kg saline bolus into the venous vasculature, followed by the acquisition of pre and post bolus 3D angiograms to observe alterations induced by the bolus, concurrently with intravascular pressure measurements in target regions. We are then able to measure the circumference and the cross-sectional area of the vessel pre and post bolus. With these data and the intravascular pressure, we are able to calculate the compliance and distensibility with specific equations. This method was used to compare the inferior vena cava's compliance and distensibility in native unoperated sheep to the conduit of sheep implanted with a long-term expanded polytetrafluorethylene (PTFE) graft. The native vessel was found to be more compliant and distensible than the PTFE graft at all measured locations. We conclude that this method safely provides in vivo measurements of vein compliance and distensibility.

Intravascular Iliac Artery Lithotripsy to Facilitate Aortic Endograft Delivery: Midterm Results of a Dual-Center Experience.

To assess the feasibility and safety of intravascular lithotripsy (IVL) for enabling transfemoral abdominal (EVAR), thoracic (TEVAR), and thoracoabdominal (BEVAR) endovascular aneurysm repair in patients with narrow and calcified iliac arteries. Consecutive patients treated with IVL for severe calcified and narrowed iliac access before EVAR, TEVAR, or BEVAR between November 2020 and June 2022 were retrospectively evaluated. All anatomical iliac characteristics were acquired by multi-planar reconstruction of preoperative computed tomography angiography (CTA). The hostility of the vascular accesses was classified based on Peripheral Arterial Calcium Scoring System (PACSS) and calcified access severity score (CASS), a new score considering both anatomical (calcium grade and length, minimum lumen diameter [MLD], and tortuosity index) and aortic stent-graft (SG/MLD index) parameters. Primary endpoint was technical success defined as successful aortic endograft delivery and deployment without iliac rupture. Freedom from complications and primary patency were additionally analyzed. Twenty-eight iliac axes were treated with IVL (8 bilateral) in 20 patients (mean age 74.5±6.7 years) with a mean follow-up of 26.5±6.2 (range 17-36) months. Ten patients underwent EVAR: 3 TEVAR, and 7 BEVAR procedures. In 14 patients (70%), aneurysm disease was associated with symptomatic aorto-iliac occlusive disease (AIOD), with Rutherford class III to IV. The PACSS was grade IV in 89% of the cases and the CASS (mean 14±2) was grade III to IV in all cases. The stent-graft (SG) outer diameter (5.60±1.65 mm) was significantly larger by 50% than MLD (3.96±1.20 mm), with an SG/MLD index of 1.50±0.51 (p<0.001). Technical success was 100%. No dissection, rupture, or distal embolization occurred. One (3.4%) bail-out stenting was necessary as endoconduit after IVL treatment. One month CTA showed that postoperative luminal gain increased by 93% (p<0.001). An improvement of 2 Rutherford classes occurred in all AIOD patients with a primary patency of 100% at last follow-up. This study shows the safety and feasibility of IVL as a valuable option to treat narrow and calcified iliac arteries to facilitate endograft delivery. Further studies will be useful to confirm these results. In this article, the use of intravascular iliac artery lithotripsy to facilitate aortic endograft delivery is explored. The presence of iliac severe calcifications still represents a contraindication for aortic endovascular repair. Intravascular lithotripsy increases the feasibility and safety of endovascular aortic procedures, facilitating endograft delivery and reducing the risk of iliac rupture and/or dissections by improving vessel compliance and luminal gain. This novel vessel preparation could be an alternative to "paving and cracking" and/or iliac conduits. This study describes a new score to classify the severity of iliac calcifications, considering anatomical parameters and the profile of aortic endografts delivery system.

Theoretical and Finite Element Analysis of Pressure Vessel

Objectives: This study tests the vessel strength and performance of pressure vessel under Internal pressure, Nozzle loads, and Hydro-test using Ansys APDL, validating design alignment with ASME Section VIII following the Design by rule (Analytical) and Design by Analysis (FEA) accurate elastic analysis approach. Methods: This study employs ASME methods to validate vessel integrity under various loads. Strength is confirmed through analytical formulas and Finite Element Analysis (FEA) using ANSYS APDL, aligned with widely used ASME BPVC codes in the oil and gas industry. The FE model, utilizing hex elements, ensures result accuracy with a minimum of three elements across thickness. Boundary conditions are validated by comparing hoop stress in FEA with analytically calculated values. ASME's computationally efficient elastic analysis, employing a linear approach, includes stress linearization at discontinuity and non-discontinuity locations, verifying vessel design through analysis. Findings: Initial thicknesses for the shell and cone exceeded analytically calculated minimums, affirming vessel structural integrity through ASME's design by rule approach. Finite Element Analysis (FEA) stress analysis at critical points, such as nozzle junctions and other discontinuity areas, validates accuracy through hoop stress checks. Analysis of design and test load cases reveals stress categories well within ASME Sec VIII limits, confirming the vessel's safety and compliance with elastic stress analysis standards. Novelty: This method emerges as a reliable tool for vessel design, ensuring safety and ASME compliance, particularly beneficial for industries like oil and gas. It provides precise guidelines utilizing hex mesh, validates boundary conditions through hoop stress comparison, and comprehensively assesses stress in critical and non-critical zones through elastic stress analysis. Addressing common challenges identified in the literature review, this approach enhances the accuracy and reliability of pressure vessel designs in compliance with ASME standards for design and test loadings. Keywords: Pressure Vessels, Process Industries, Stress, Loads, Pressure, Thermal, Design Validation, ASME, FE analysis

Isotonic hydroxyethyl starch is ineffective in restoring blood pressure during experimental septic shock: Implications for fluid resuscitation strategies

Objectives: The objectives of the study were to evaluate the effect of isotonic or hypertonic hydroxyethyl starch (HES) solutions on blood pressure and to assess the influence of the neurohypophyseal system on this response during experimental septic shock. Male Wistar rats were randomly allocated to undergo either cecal and ligation puncture (CLP) or a simulated surgical procedure (sham). Materials and Methods: Of 6 h post-surgery, either isotonic saline (0.9% sodium chloride, 4 mL/kg), isotonic (HES; at doses of 4, 8 or 16 mL/kg), or hypertonic saline-HES (HS-HES; 4 mL/kg) was administered through the endovenous route, followed by the recording of blood pressure and heart rate. In addition, the levels of sodium, vasopressin, and oxytocin were evaluated after the fluid infusion. Results: The administration of HES did not have a significant effect on blood pressure in our study. However, the HS-HES solution increased plasma osmolality, sodium, vasopressin, and oxytocin levels. Furthermore, the HS-HES induced a transient elevation in blood pressure immediately after infusion, which could be completely blunted by the pre-administration of a V1-vasopressin antagonist. Conclusion: Our results demonstrate that the infusion of an isotonic blood volume expander during experimental septic shock is ineffective in restoring blood pressure due to blood vessel compliance. In contrast, the infusion of a hypertonic solution stimulates vasopressin secretion and can transiently restore blood pressure.

Amyloid β interferes with wound healing of brain microvascular endothelial cells by disorganizing the actin cytoskeleton

Cerebral amyloid angiopathy (CAA) is a disease in which amyloid β (Aβ) is deposited in the cerebral blood vessels, reducing compliance, tearing and weakening of vessel walls, leading to cerebral hemorrhage. The mechanisms by which Aβ leads to focal wall fragmentation and intimal damage are not well understood. We analyzed the motility of human brain microvascular endothelial cells (hBMECs) in real-time using a wound-healing assay. We observed the suppression of cell migration by visualizing Aβ aggregation using quantum dot (QD) nanoprobes. In addition, using QD nanoprobes and a SiR-actin probe, we simultaneously observed Aβ aggregation and F-actin organization in real-time for the first time. Aβ began to aggregate at the edge of endothelial cells, reducing cell motility. In addition, Aβ aggregation disorganized the actin cytoskeleton and induced abnormal actin aggregation. Aβ aggregated actively in the anterior group, where cell motility was active. Our findings may be a first step toward explaining the mechanism by which Aβ causes vascular wall fragility, bleeding, and rebleeding in CAA.

Coronary intravascular lithotripsy in contemporary practice: challenges and opportunities in coronary intervention.

Percutaneous coronary intervention (PCI) of calcified coronary arteries is associated with poor outcomes. Poorly modified calcified lesion hinders the stent delivery, disrupts drug-carrying polymer, impairs drug elution kinetics and results in under-expanded stent (UES). UES is the most common cause of acute stent thrombosis and in-stent restenosis after PCI of calcified lesions. Angiography has poor sensitivity for recognition and quantification of coronary calcium, thereby mandating the use of intravascular imaging. Intravascular imaging, like intravascular ultrasound and optical coherence tomography, has the potential to accurately identify and quantify the coronary calcium and to guide appropriate modification device before stent placement. Available options for the modification of calcified plaque include modified balloons (cutting balloon, scoring balloon and high-pressure balloon), atherectomy devices (rotational atherectomy and orbital atherectomy) and laser atherectomy. Coronary intravascular lithotripsy (IVL) is the newest addition to the tool box for calcified plaque modification. It produces the acoustic shockwaves, which interact with the coronary calcium to cause multiplanar fractures. These calcium fractures increase the vessel compliance and result in desirable minimum stent areas. Coronary IVL has established its safety and efficacy for calcified lesion in series of Disrupt CAD trials. Its advantages over atherectomy devices include ease of use on workhorse wire, ability to modify deep calcium, no debris embolization causing slow flow or no-flow and minimal thermal injury. It is showing promising results in modification of difficult calcified lesion subsets such as calcified nodule, calcified left main bifurcation lesions and chronic total occlusion. In this review, authors will summarize the mechanism of action for IVL, its role in contemporary practice, evidence available for its use, its advantages over atherectomy devices and its imaging insight in different calcified lesion scenarios.

Analytical and numerical solution and multi-objective optimization of tetra-star-chiral auxetic stents

The present study examines the mechanical properties of auxetic stents with the tetra-star-chiral structure. The tetra-star-chiral geometry is parametrically modeled. Then, the design of experiments (DOE) is developed by defining the elastic properties of the stents and using the response surface method (RSM). Finite element (FE) analysis is performed in order to find a polynomial relationship between the geometric parameters as inputs and the elastic parameters as the outputs. Then, the optimal stent is found in terms of elasticity parameters by using RSM and NSGA-II methods and the two-dimensional Pareto front is plotted. The optimal parameters of the stent including flexural stiffness, axial elasticity modulus, radial elasticity modulus and Poisson’s ratio are obtained as 10.66 mPa m4, 5.37 MPa, 33.2 MPa and − 0.41, respectively. Moreover, a method is proposed to find an analytical solution for metal elastic stents in order to verify the FE model results, and also the blood vessel compliance of the optimal stent is examined.

Biomimetic crimped/aligned microstructure to optimize the mechanics of fibrous hybrid materials for compliant vascular grafts

The precise mechanical properties of many tissues are highly dependent on both the composition and arrangement of the nanofibrous extracellular matrix. It is well established that collagen nanofibers exhibit a crimped microstructure in several tissues such as blood vessel, tendon, and heart valve. This collagen fiber arrangement results in the classic non-linear ‘J-shaped’ stress strain curve characteristic of these tissues. Synthetic biomimetic fibrous materials with a crimped microstructure similar to natural collagen demonstrate similar mechanical properties to natural tissues. The following work describes a nanofabrication method based on electrospinning used to fabricate two component hybrid electrospun fibrous materials that mimic the microstructure and mechanical properties of vascular tissue. The properties of these samples can be precisely and predictably optimized by modifying fabrication parameters. Tubular grafts with biomimetic microstructure were constructed to demonstrate the potential of this fabrication method in vascular graft replacement applications. It was possible to closely match both the overall geometry and the compliance of specific blood vessels by optimizing graft microstructure.

Intravascular Lithotripsy for Vessel Preparation in Calcified Coronary Arteries Prior to Stent Placement - Japanese Disrupt CAD IV Study 2-Year Results.

Background: Intravascular lithotripsy (IVL) delivers acoustic pressure waves to modify calcification to enhance vessel compliance and optimize stent deployment. The Disrupt CAD IV study enrolled patients with severe coronary artery calcification. The primary safety (30-day major adverse coronary events [MACE], 6.3%) and effectiveness (procedural success, 93.8%) endpoints were achieved. The present analysis evaluated the 2-year outcomes of the study. Methods and Results: Disrupt CAD IV (NCT04151628) was a prospective, single-arm, multicenter study designed for regulatory approval of the Shockwave Coronary C2 IVL system in Japan. Angiographic outcomes were analyzed by an independent core laboratory and adverse events were adjudicated by a Clinical Events Committee. Kaplan-Meier analysis was performed for MACE (composite of cardiac death, MI or target-vessel revascularization [TVR]), target lesion failure (TLF: composite of cardiac death, TV-MI, and target lesion revascularization [TLR]), and stent thrombosis (ST). At 2 years, 62 subjects had completed follow-up. MACE occurred in 12.6% (cardiac death 0.0%, MI 6.3%, TVR 7.9%) and TLF occurred in 7.8% of patients, with both rates driven by non-Q-wave MI events (6.3%). TLR was 3.2%; no ST occurred through 2 years. Conclusions: Treatment with IVL in patients with severely calcified coronary lesions was associated with low rates of MACE, TLR, and ST at 2 years, demonstrating continued durable safety and effectiveness of coronary IVL in a Japanese population.

Intravascular laser lithotripsy for calcium fracture in human coronary arteries.

Electrical intravascular lithotripsy (E-IVL) uses shock waves to fracture calcified plaque. We aimed to demonstrate the ability of laser IVL (L-IVL) to fracture calcified plaques in ex vivo human coronary arteries and to identify and evaluate the mechanisms for increased vessel compliance. Shock waves were generated by a Ho:YAG (Holmium: yttrium-aluminium-garnet) laser (2 J, 5 Hz) and recorded by a high-speed camera and pressure sensor. Tests were conducted on phantoms and 19 fresh human coronary arteries. Before and after L-IVL, arterial compliance and optical coherence tomography (OCT) pullbacks were recorded, followed by histology. Additionally, microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) were performed. Finite element models (FEM) were utilised to examine the mechanism of L-IVL. Phantom cracks were obtained using 230 μm and 400 μm fibres with shock-wave pressures of 84±5.0 atm and 62±0.4 atm, respectively. Post-lithotripsy, calcium plaque modifications, including fractures and debonding, were identified by OCT in 78% of the ex vivo calcified arteries (n=19). Histological analysis revealed calcium microfractures (38.7±10.4 μm width) in 57% of the arteries which were not visible by OCT. Calcium microfractures were verified by micro-CT and SEM. The lumen area increased from 2.9±0.4 to 4.3±0.8 mm2 (p<0.01). Arterial compliance increased by 2.3±0.6 atm/ml (p<0.05). FEM simulations suggest that debonding and intimal tears are additional mechanisms for increased arterial compliance. L-IVL has the capability to increase calcified coronary artery compliance by multiple mechanisms.

Enhancing decellularized vascular scaffolds with PVDF and PCL reinforcement: a fused deposition modeling approach

BackgroundDecellularized xenogenic scaffolds represent a promising substrate for tissue-engineered vascular prostheses, particularly those with smaller diameters (&amp;lt;6 mm). Despite their benefits, a notable limitation presents itself during decellularization, namely, the diminished mechanical strength that introduces the risk of aneurysmal dilations in the early post-implantation period. This study introduces a strategy for modification the mechanical properties of these biological scaffolds through the forming of an external polymeric reinforcement via thermal extrusion.MethodsThe study utilized scaffolds fabricated from bovine internal mammary arteries through decellularization and preservation. The scaffolds were divided into subgroups and reinforced with polymeric helices made of Polyvinylidene fluoride (PVDF) and Polycaprolactone (PCL), n = 5 for each. An experimental setup for external reinforcement coating was designed. Computed microtomography was employed to obtain accurate 3D models of the scaffolds. Mechanical properties were evaluated through in vitro uniaxial tension tests (Z50, Zwick/Roell, Germany), compliance evaluation and numerical simulations (Abaqus/CAE, Dassault Systemes, France) to investigate the effect of external reinforcement on aneurysm growth.ResultsUsing a double-layer helix for the reinforcement significantly enhanced the radial tensile strength of the scaffolds, increasing it up to 2.26 times. Yet, the comparison of vessel's compliance between two reinforced and the Control scaffolds within the physiological pressures range did not reveal any significant differences. Numerical simulation of aneurysm growth showed that thin-walled regions of the Control scaffold developed aneurysmal-type protrusions, bulging up to 0.7 mm, with a substantial degradation of mechanical properties. In contrast, both PVDF and PCL reinforced scaffolds did not exhibit significant property degradation, with deformations ranging 0.1–0.13 mm depending on the model, and a maximum decrease in the modulus of elasticity of 23%.ConclusionThe results of the study demonstrated that the external polymer helical reinforcement of decellularized scaffolds via thermal extrusion enables a controlled modification of mechanical properties, notably enhancing radial strength while maintaining sufficient compliance within the physiological pressure range. A series of in vitro tests demonstrated the consistency and potential of this approach for decellularized xenogenic scaffolds, a concept that had not been explored before.

The so-called ligamentum arteriosum is innervated.

The ductus arteriosus is a muscular artery connecting the pulmonary trunk directly to the aorta in fetal circulation in order to by-pass the fluid filled lungs. Post-natally, this vessel is speculated to undergo obliteration, fibrosis and ultimately metamorphosize into a band of ligament, thereby changing name from the ductus arteriosus to the ligamentum arteriosum (LA). Earlier studies into the innervation of the ductus arteriosus reported innervation from the left aortic and vagus nerves. However, information of what becomes of the innervation is scanty and contradictory. I hypothesized that; this fetal shunt still receives innervation even in post-uterine life. To test this, LA of human, pig, and wild-type mice were studied using double-immunofluorescence labeling using antibodies directed against structural and general neuronal marker proteins (Smooth muscle actin and Protein gene product 9.5 (PGP 9.5, respectively). Additionally, TEM studies were performed on mouse LA. Results from the present study demonstrates an extensive innervation of the LA in animals (mice and pigs) and in senescent humans validated by two independent methods, i.e., immunolabeling with antibody directed against PGP 9.5 and TEM. Intense immunoreactivity was clearly visible in samples subjected to PGP-immunolabeling. TEM revealed the presence of nerve terminals with about 30% of all nerve terminals observed less than 1 μm away from smooth muscle cells within the LA. This clearly differs from elastic arteries, where the distance between autonomic terminals and smooth muscle cells is rarely less than 1 μm. Conceivably, these results imply that the so- called LA receives innervation representative of that present within the ductus arteriosus during fetal life. This provides the first reliable study of innervation of the LA and makes room for further investigation into the neurochemistry of this innervation. This is crucial as the presence of nerve terminals may play a role in vessel compliance or impedance of the two great vessels related to this structure. The substances released by these fibers may also have an influence on cells and tissues in the immediate microenvironment of this structure.