Impact of Impeller Speed Adjustment Interval on Hemolysis Performance of an Intravascular Micro-Axial Blood Pump.

BACKGROUND: In recent years, intravascular micro-axial blood pumps have been increasingly used in the treatment of patients with cardiogenic shock. The flow rate of such blood pumps requires adjustment based on the patient's physiological condition. Compared to a stable flow state with fixed rotation speed, adjusting the speed of blood pump impeller to alter flow rate may lead to additional hemolysis. This study aimed at elucidating the relationship between adjusting interval of a blood pump's impeller speed and the hemolysis index. METHODS: By comparing simulation results with P-Q characteristic curves of the blood pump measured by experiments, the accuracy of the blood pump flow field simulation model was confirmed. In this study, a drainage tube was employed as the device analogous to an intravascular micro-axial blood pump for achieving similar shear stress levels and residence times. The hemolysis finite element prediction method based on a power-law model was validated through hemolysis testing of porcine blood flow through the drainage tube. The validated models were subsequently utilized to investigate the impact of impeller speed adjusting intervals on hemolysis in the blood pump. RESULTS: Compared to steady flow, the results demonstrate that the hemolysis index increased to 6.3% when changing the blood pump flow rate from 2 L/min to 2.5 L/min by adjusting the impeller speed within 0.072 s. CONCLUSIONS: An adjustment time of impeller speed longer than 0.072 s can avoid extra hemolysis when adjusting the intravascular micro-axial blood pump flow rate from 2 L/min to 2.5 L/min.

[Progress in the analysis of hemolysis and coagulation models for interventional micro-axial flow blood pumps].

Interventional micro-axial flow blood pump is widely used as an effective treatment for patients with cardiogenic shock. Hemolysis and coagulation are vital concerns in the clinical application of interventional micro-axial flow pumps. This paper reviewed hemolysis and coagulation models for micro-axial flow blood pumps. Firstly, the structural characteristics of commercial interventional micro-axial flow blood pumps and issues related to clinical applications were introduced. Then the basic mechanisms of hemolysis and coagulation were used to study the factors affecting erythrocyte damage and platelet activation in interventional micro-axial flow blood pumps, focusing on the current models of hemolysis and coagulation on different scales (macroscopic, mesoscopic, and microscopic). Since models at different scales have different perspectives on the study of hemolysis and coagulation, a comprehensive analysis combined with multi-scale models is required to fully consider the influence of complex factors of interventional pumps on hemolysis and coagulation.

Endovascular repair combined with in situ fenestration for new-onset or residual arch dissection in patients underwent aortic replacement.

INTRODUCTION: Ascending aorta or hemi-arch replacement is a frequently used treatment for patients with acute type A thoracic aortic dissection, particularly those who are elderly or have multiple comorbidities. However, in cases where there are secondary entry tears in the aortic arch or descending aorta, this procedure may not fully resolve the issue. The true lumen may remain compressed due to perfusion of the false lumen and usually require reoperation. METHODS: Between January 2019 and July 2022, 18 patients underwent endovascular total aortic arch repair and fenestration technique without requiring median re-sternotomy. Aortic stent grafts were implanted via the femoral approach, utilizing prosthetic vessels as an appropriate proximal landing zone for aortic stent graft deployment. Based on the debranching conditions of the arch in previous surgery, single, double or triple in situ fenestrations (ISFs) were performed, respectively. RESULTS: All 18 cases were technically successful, with a median follow-up period of 20 months (range: 18-31 months). All patients had a favourable postoperative course, with no deaths within 30 days or during their hospital stay. There were no instances of disabling stroke, paraplegia, endo-leak, stent graft migration or stent graft-induced new entry. In addition, all patients exhibited complete thrombosis of the false lumen at the level of the aortic arch. CONCLUSION: Our preliminary experience suggests that endovascular total arch repair combined with ISF technique is a viable, effective and safe option for treatment. Our mid-term results have been promising, but we acknowledge the need for further evaluation to assess long-term outcomes and durability.

Left Atrial Appendage Occlusion Guided Only by Transesophageal Echocardiography.

AIMS: To investigate a new method of left atrial appendage occlusion without fluoroscopy. METHODS AND RESULTS: We performed left atrial appendage occlusion for 14 patients with atrial fibrillation in our hospital. All of the surgeries were completed in a general surgery setting, avoiding fluoroscopy, and in each case, the entire procedure was guided by transesophageal echocardiography (TEE). All of the surgeries were performed through the femoral vein pathway. All operations went smoothly with no serious complications. Postoperative TEE indicated that each device was in a good position, and there was no residual shunt around any of the devices. CONCLUSIONS: TEE-guided left atrial appendage occlusion is safe and reliable, simplifies the procedure, protects doctors and patients from radiation, and is gradually becoming the mainstream operation for left atrial appendage occlusion. This trial is registered with ChiCTR1800018387.

Estrogen Receptor α and ß in Mouse: Adipose-Derived Stem Cell Proliferation, Migration, and Brown Adipogenesis In Vitro.

BACKGROUND/AIMS: Adipose-derived stem cells (ASCs) belong to mesenchymal stem cells and may play a potential role as seeding cells in stem cell transplantation. To be able to exploit stem cells as therapeutic tool, their defects in some important cellular functions, such as low survival rate and cellular activity, should be considered. This is especially the case for stem cells that are intended for transplantation. Of note, stem cell responses to hormones should be considered since estrogen is known to play a critical role in stem cell behavior. However, different impacts of the estrogen receptor (ER) types α and ß have not been fully determined in ASC function. In this study, we investigated effects of ERα and ERß on ASC proliferation, migration, as well as in adipogenesis. METHODS: ASCs obtained from mice were cultured with 100nM ERα or ERß agonist PPT and DPN, respectively. The ERα and ERß antagonist ICI 182,780 (100nM) was used as control. RESULTS: Compared to ERß, ERα appears more potent in improving ASC proliferation and migration. Investigation of adipogenesis revealed that ERß played a significant role in suppressing ASC-mediated brown tissue adipogenesis which is in contrast to ERα. These results correlated with reduced mRNA expression of UCP-1, PGC-1α and PPAR-x03B3;. CONCLUSIONS: ERα plays a more critical role in promoting ASC proliferation and migration while ERß is more potent in suppressing ASC brown adipose tissue differentiation mediated by decreased UCP-1, PGC-1α and PPAR-x03B3; expression.

Comparison of the safety of right internal mammary artery versus radial artery for the second arterial conduit during coronary artery bypass grafting.

OBJECTIVE: To compare the safety of procedure in patients receiving right internal mammary artery (RIMA) versus radial artery (RA) as the second arterial graft during left internal mammary artery bypass surgery. METHODS: A literature search was performed, and observational studies comparing RA and RIMA as a second arterial conduit were included. The end points included in-hospital mortality, sternal wound infection (SWI), myocardial infarction (MI), reoperation for bleeding, stroke and low cardiac output syndrome. Sensitivity analysis was performed, and publication bias was assessed. RESULTS: Analysis of nine studies comprising 1,738 RIMA patients and 1,906 RA patients showed a similar risk of in-hospital mortality (relative risk [RR] 1.13, 95% confidence interval [CI] 0.64 to 1.98) between two groups. The risk of SWI in RIMA patients was significantly higher than that in RA patients (RR 3.19, 95% CI 1.64 to 6.20). The risk of the rest end points did not differ. CONCLUSIONS: The postoperative risk seems to be similar between RIMA group and RA group, except the higher risk of SWI in RIMA patients. The surgeon relies on his own experience with these two arterial grafts and assessment of the patient profile to decide the choice of the second arterial conduit.

Cardioprotective activity of placental growth factor in a rat model of acute myocardial infarction: nanoparticle-based delivery versus direct myocardial injection.

BACKGROUND: To comparatively evaluate the cardioprotective activity of placental growth factor (PGF) delivered through direct injection and a nanoparticle-based system respectively and to study the underlying mechanisms in a rat model of acute myocardial infarction (AMI). METHODS: Poly lactic-co-glycolic acid (PLGA)-based PGF-carrying nanoparticles (PGF-PLGANPs) were created. The mean size and morphology of particles were analyzed with particle size analyzer and transmission electronic microscopy (TEM). Encapsulation efficiency and sustained-release dose curve were analyzed by ELISA. Sprague-Dawley rats were randomized into four groups (n = 10). While animals in the first group were left untreated as controls, those in the other 3 groups underwent surgical induction of AMI, followed by treatment with physiological saline, PGF, and PGF-PLGANPs, respectively. Cardiac function was evaluated by transthoracic echocardiography at 4 weeks after treatment. At 6 weeks, rats were sacrificed, infarction size was analyzed with Masson trichrome staining, and protein contents of TIMP-2, MT1-MMP and MMP-2 at the infarction border were determined by immunohistochemistry and western blotting analysis. RESULTS: PGF was released for at least 15 days, showing successful preparation of PGF-PLGANPs. Coronary artery ligation successfully induced AMI. Compared to physiological saline control, PGF, injected to the myocardium either as a nude molecule or in a form of nanoparticles, significantly reduced infarction size, improved cardiac function, and elevated myocardial expression of TIMP-2, MT1-MMP, and MMP-2 (P < 0.05). The effect of PGF-PLGANPs was more pronounced than that of non-encapsulated PGF (P < 0.05). CONCLUSION: Target PGF delivery to myocardium may improve cardiac function after AMI in rats. PLGA-based nanoparticles appear to be a better approach to delivery PGF. PGF exerts its cardioprotective effect at least partially through regulating metalloproteinase-mediated myocardial tissue remodeling.

Bilateral internal mammary artery grafting and risk of sternal wound infection: evidence from observational studies.

BACKGROUND: The advantageous survival outcome of bilateral internal mammary artery grafting (BIMA) has been well established. However, this meta-analysis aims to make clear whether BIMA grafting increases the risk of sternal wound infection (SWI) when compared with single internal mammary artery grafting (SIMA). METHODS: A literature search was performed in PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. The observational studies reporting a comparison between SIMA and BIMA were included. The outcome of interest was the risk of SWI. Literature search, data extraction, and quality assessment were performed. Sensitivity and publication bias were also assessed in this research. RESULTS: We identified 4,701 titles and included 32 studies finally. The meta-analysis showed that the risk of SWI in the BIMA group was higher (relative risk [RR] 0.62, 95% confidence interval [CI] 0.55 to 0.71) than that in the SIMA group. Moreover, BIMA grafting was also associated with a higher risk of SWI in diabetic patients (RR 0.65, 95% CI 0.52 to 0.81) as well as elderly patients (RR 0.45, 95% CI 0.33 to 0.62). When skeletonization technique was adopted, the risk of SWI in BIMA patients was just a little higher than that in SIMA patients, but the difference did not reach statistical significance (RR 0.84, 95% CI 0.54 to 1.31). CONCLUSIONS: The BIMA grafting increases the risk of SWI when compared with SIMA grafting. This adverse effect further extends to diabetic and elderly patients. As regarding the method of procurement, skeletonized BIMA is safe and effective, thus it should be the procedure recommended.