Cardiovascular Engineering and Technology最新文献

Background: Mechanical circulatory support devices (MCSDs) have gradually become an effective treatment of end-stage heart failure (HF). However, the introduction of foreign surfaces and non-physiological shear stress (NPSS) can cause severe damage to various blood cells, leading to impaired function of immune system and increased risk of complications such as inflammation and thrombosis. The effect of mechanical injury on white blood cell (WBC) has been largely neglected compared to that on red blood cell (RBC) and platelet (PLT).

Method: To better understand the impact of MCSDs on WBCs and emphasize the importance of investigating WBC damage to avoid adverse events during mechanical circulatory support, this review elaborated the induction of WBC phenotypic and functional injury by MCSD-related factors, and the relationship between injury and clinical complications. Furthermore, this article provided a detailed review and comparative analysis of in vitro blood-shearing devices (BSDs) and detection methods used in WBC damage investigation.

Results: NPSS, biomaterials and other related factors can activate WBC, decrease WBC function, and promote the release of pro-inflammatory and pro-thrombotic microparticles, increasing the risk of inflammation and thrombotic complications. The evaluation of WBC damage typically involves measuring cell viability and dysfunction using in vitro BSDs (e.g. concentric cylinder devices) and injury detection methods (e.g. flow cytometry).

Conclusions: WBCs with normal morphology may also experience functional failure due to NPSS from MCSDs, leading to sublethal mechanical cell injury. Therefore, the effect of MCSDs on WBCs can be more comprehensively evaluated by a combination of measuring cell functional capacity and cell counting.

Purpose: The initiation of intracranial aneurysms has long been studied, mainly by the evaluation of the wall shear stress field. However, the debate about the emergence of hemodynamic stimuli still persists. This paper builds on our previous hypothesis that secondary flows play an important role in the formation cascade by examining the relationship between flow physics and vessel geometry.

Methods: A composite evaluation framework was developed to analyze the simulated flow field in perpendicular cross-sections along the arterial centerline. The velocity field was decomposed into secondary flow components around the centerline in these cross-sections, allowing the direct comparison of the flow features with the geometrical parameters of the centerline. Qualitative and statistical analysis was performed to identify links between morphology, flow, and the formation site of the aneurysms.

Results: The normalized mean curvature and curvature peak were significantly higher in the aneurysmal bends than in other arterial bends. Similarly, a significant difference was found for the normalized mean velocity ( $p=0.0274$ ), the circumferential ( $p=0.0029$ ), and radial ( $p=0.0057$ ) velocity components between the arterial bends harboring the aneurysm than in other arterial bends. In contrast, the difference of means for the normalized axial velocity is insignificant ( $p=0.1471$ ).

Conclusion: Thirty cases with aneurysms located on the ICA were analyzed in the virtually reconstructed pre-aneurysmal state by an in-silico study. We found that sidewall aneurysm formation on the ICA is more probable in these arterial bends with the highest case-specific curvature, which are accompanied by the highest case-specific secondary flows (circumferential and radial velocity components) than in other bends.

Purpose: Dysfunction of vasomotor reactions due to arteriolar smooth muscle causes serious adverse events, such as loss of hemodynamic coherence. This in turn can increase risks of cardiovascular-related diseases. A noninvasive and quantitative evaluation of microvascular disorder is therefore very important for early diagnosis and treatment. This paper describes a new approach to the assessment of vasomotor functions using the arteriolar elasticity measurement technique in the fingertip.

Methods: A recently developed device, modified to detect a photoplethysmogram with green light (gPPG) in arteriolar regions, allowed the measurement of arteriolar blood pressure (BP_ca.) and gPPG from a left index fingertip placed on an occlusive cuff of the device. Arteriolar stiffness and distensibility were analyzed as effective elasticity indices, as a function of arteriolar distending pressure derived by volume-oscillometry. Cold pressor tests to induce vasoconstriction were carried out whether appropriate elasticity changes could be obtained.

Results: Experiments using 6 healthy subjects were successfully made to obtain arteriolar elastic properties before and while immersing a right hand in cold water. The index-values of stiffness and distensibility showed, respectively, a considerable increase and decrease, clearly demonstrating the appropriate elasticity changes with vasoconstrictive reactions.

Conclusion: Although a further study using many subjects is needed, the results so far suggest that this method could easily provide important features to acquire quantitatively arteriolar elasticity together with BP_ca. and to assess vasomotor functions in the microvasculature. This convenient method appears useful for clinical practices and health management and promising also for screening cardiovascular-related diseases. (242/250 words).

Effective diagnosis of electrocardiogram (ECG) is one of the simplest and fastest ways to assess the heart's function. In the recent decade, various attempts have been made to automate the classification of electrocardiogram signals to detect heartbeat arrhythmias based on deep learning. However, due to the lack of a comprehensive standard for how to divide the database into the train and test datasets and the variety of methods used for this purpose, it is not possible to make a fair comparison between many of these studies. One of the main criteria for creating train and test datasets that have a great impact on the final results is their distribution paradigm. There are three paradigms for this purpose, including Inter-Patient, Intra-Patient, and Patient-Specific. In this research, we have conducted a detailed study of the impact of these three paradigms on the final results obtained from a CNN-based deep learning model for the classification of heartbeat arrhythmia into five classes. The experimental results on the standard arrhythmia dataset show that the Patient-Specific reached the best average performance in all of the metrics. Also, this training pattern is more practical and can be employed to create patient customized devices for the classification of ECG arrhythmia.

Purpose: Aortic valve stenosis (AVS) is the most common valvular disease in developed countries. Surgical or transcatheter bioprosthetic aortic valve (AV) replacement is the standard treatment for severe AVS. However, bioprostheses are prone to structural degeneration. Hence, in terms of lifetime management, there is a need for therapies that can postpone AV replacement. With the aim of fragmenting calcifications and restoring AV leaflets flexibility, a new transcatheter debridement device (TDD) exploiting ultrasound is under development. We performed an ex-vivo study on human hearts to quantify how TDD treatment affects stenotic AVs hemodynamic. Additionally, a qualitative histological analysis was performed to assess TDD's impact on AV leaflets.

Methods: Three human hearts affected by AVS were characterized pre- and post-treatment in an ex-vivo beating heart simulator. To replicate physiological flowrates, a pulsatile pump was connected to the left ventricle, while a systemic impedance simulator connected to the aortic root and a reservoir connected to the left atrium closed the hydraulic circuit. Transvalvular pressure drop (ΔPsys), backflow volume, and effective orifice area (EOA) were evaluated. For histological analysis, AV leaflets sections were stained with Haematoxylin/Eosin and AlizarineRedS to highlight calcifications.

Results: The treatment induced a reduction in ΔPsys in all tested samples, improving EOA, but caused an increase in backflow volume. Moreover, histology suggested AV leaflets integrity.

Conclusions: The TDD procedure improved AV fluid-dynamics during systole in all tested samples, without evidence of damage to tissues. This suggests TDD could be a promising option to postpone AV replacement for patients with AVS.

Purpose: Atrial fibrillation (AF) is the most common chronic cardiac arrhythmia that increases the risk of stroke, primarily due to thrombus formation in the left atrial appendage (LAA). Left atrial appendage occlusion (LAAO) devices offer an alternative to oral anticoagulation for stroke prevention. However, the complex and variable anatomy of the LAA presents significant challenges to device design and deployment. Current benchtop models fail to replicate both anatomical variability and physiological hemodynamics, limiting their utility. This study introduces a novel left atrial cardiac simulator that incorporates patient-derived LAA models within a benchtop circulatory flow loop, enabling high-fidelity LAAO device testing and development.

Methods: A rigid, patient-derived left atrium (LA) model was 3D printed from segmented MRI data and modified to accommodate attachment of patient-specific LAA models. A library of LAA geometries was fabricated using silicone casting techniques to replicate the mechanical properties of native tissue. The LA-LAA model was integrated into a circulatory flow loop equipped with a pulsatile pump, pressure sensors, and flow probes, allowing real-time hemodynamic analysis. System tunability was demonstrated by varying heart rate, stroke volume, resistance, and compliance to simulate physiological and pathological conditions.

Results: The simulator accurately replicated LA pressure and flow waveforms, closely approximating physiological conditions. Changes in heart rate, stroke volume, and compliance effectively modulated LAP and LA inflow before and after LAAO. Distinct pressure and flow waveforms were observed with different LAA geometries. Hemodynamic analysis revealed increased left atrial pulse pressure after occlusion, with the greatest increase occurring after complete exclusion of the LAA. The simulator facilitated the evaluation of LAAO device performance, including metrics such as seal and PDL, and served as an effective training tool for iterative device deployment and recapture with visual and imaging-guided feedback.

Conclusions: The left atrial cardiac simulator offers a highly tunable and realistic platform for testing and developing LAAO devices. It also serves as an effective procedural training tool, allowing for the simulation of patient-specific anatomical and hemodynamic conditions. By enabling these advanced simulations, the simulator enhances pre-procedural planning, device sizing, and placement. This innovation represents a significant step toward advancing personalized medicine in atrial fibrillation management and improving LAAO outcomes.

Purpose: This study addresses the critical gap in the literature regarding the comparative analysis of axial flow left ventricular assist devices (LVADs). Despite technological advancements, there is a notable lack of integrated studies focusing solely on axial flow pumps and comparing multiple models with the same technology. This gap limits developers' access to comprehensive technical information essential for innovation in mechanical design, flow efficiency, and thrombus prevention.

Method: A systematic review of 27 low-risk studies was performed on four axial flow LVADs: HeartMate II, DeBakey, Berlin Heart INCOR, and Jarvik 2000. The analysis evaluated durability and reliability using key metrics, including actuarial survival rates, device exchange rates, pump thrombosis rates, and freedom from adverse events, while considering technical factors such as rotor design, flow dynamics, and material innovation.

Results: HeartMate II achieved a 79% actuarial survival rate at 1 year and a 6.3% thrombosis-related exchange rate. DeBakey had a higher exchange rate of 33.3% due to mechanical issues, indicating a need for better material durability. Jarvik 2000 offered long-term support with a 5-year duration and an 8.3% thrombosis rate, benefiting from its spiral cable design. INCOR showed high reliability with low energy consumption and minimal driveline infections, highlighting the advantages of advanced coatings and reduced friction.

Conclusion: Axial flow LVADs are crucial for patients with small chest spaces, especially children. Enhancements in rotor design, materials, and real-time monitoring are essential for improving durability and reliability. These findings provide valuable insights for developing more durable and reliable axial flow pumps.

The prevalence of coronary artery disease (CAD) has become the major cause of death across the world in recent years. The accurate segmentation of coronary artery is important in clinical diagnosis and treatment of coronary artery disease (CAD) such as stenosis detection and plaque analysis. Deep learning techniques have been shown to assist medical experts in diagnosing diseases using biomedical imaging. There are many methods which employ 2D DL models for medical image segmentation. The 2D Pyramid Scene Parsing Neural Network (PSPNet) has potential in this domain but not explored for the segmentation of coronary arteries from 3D Coronary Computed Tomography Angiography (CCTA) images. The contribution of present research work is to propose the modification of 2D PSPNet into 3D PSPNet for segmenting the coronary arteries from 3D CCTA images. The innovative factor is to evaluate the network performance by employing Global processing and Patch based processing methods. The experimental results achieved a Dice Similarity Coefficient (DSC) of 0.76 for Global process method and 0.73 for Patch based method using a subset of 200 images from the ImageCAS dataset.

The widespread prevalence and significant consequences of cardiac arrhythmias have been addressed by adopting cardiac stimulation and neuromodulation implantable devices. The oldest, most commonly employed, and most well-known technology is the permanent transvenous cardiac pacemaker. However, in select emergent clinical scenarios and transient pathologies, temporary pacing is preferred. More recently, neuromodulatory vagal nerve stimulation has emerged to address neurologic, psychiatric, and nociceptive pathologies, generating significant clinical and scientific interest in the invention of temporary corollary devices for a subset of indications of nociceptive origin. The dominance of particular implant approaches and anatomic targets in both temporary pacing and neuromodulation in the clinic is owed to capabilities and limitations present in the current technological landscape. However, recent innovations in industry and academia may lead to a fundamental shift in how temporary pacing and neuromodulation are delivered in terms of procedural approach and patient outcomes. In this review, we present an overview of contemporary temporary pacemakers, neuromodulatory therapies, and devices, highlighting novel temporary pacing technologies from the clinic, industry, and academia, such as temporary permanent pacemakers, innovations in non-blood-contacting devices, bioresorbable pacemakers, and advances in neuromodulatory approaches.

Purpose: This goal of this study was to determine the impact of vascular motion on acute drug transfer and retention of drug-coated balloons (DCB) or drug-eluting stents (DES).

Methods: Commercially available paclitaxel DCBs (Lutonix & IN.PACT) and a paclitaxel DES (Zilver) were subjected to physiological flow and vascular motion conditions using a peripheral-simulating benchtop bioreactor system. Each DCB- or DES-treated artery was subjected to three sets of movement parameters including pulsatile flow with no twisting/bending (P1), pulsatile flow with 16.8° twist, 25° bend and 3.2 mm compression (P2), and pulsatile flow with 68° twist, 35° bend, 21 mm compression (P3). After 24 h, the treated segments were removed and paclitaxel concentrations were measured using pharmacokinetic analysis.

Results: In the group of arteries treated with the Lutonix DCB, there was a significant decrease in arterial paclitaxel concentrations between the P1 and both the P2 and P3 moving parameters (P1 = 404 ± 195 ng/mg, P2 = 14.9 ± 9.92 ng/mg, P3 = 19.2 ± 15.4 ng/mg; P1-P2 p = 0.007, P1-P3 p = 0.005). For the IN.PACT DCB group, no differences in the mean arterial paclitaxel concentrations were observed for the various movements (p = 0.55). Lastly, in the Zilver DES group, differences were only measured between the P2 and P3 moving parameters (P2 = 84.8 ± 32.7 ng/mg, P3 = 0.11 ± 0.06 ng/mg; P2-P3 p = 0.01).

Conclusion: Acute retention of arterial paclitaxel levels can be adversely impacted by vascular movement in both DES- and DCB- treated arteries.