Maintain Blood Flow Research Articles

2835 Evaluation of Paceycuff as a novel treatment for male stress urinary incontinence: the first UK experience

Abstract Background Prostate cancer and bladder outlet obstruction, often treated surgically, are increasing in the ageing population, leading to more cases of stress urinary incontinence (SUI). While implantable continence devices are beneficial for many, a growing number of frail patients are unsuitable for surgery and rely on incontinence pads or penile clamps, which are limited to three-hour use to prevent tissue ischaemia. We present the first UK evaluation of the new PaceyCuff penile clamp, designed for 24-hour wear while maintaining blood flow, to assess its efficacy, safety, and impact on patient quality of life. Method Men with urodynamically-proven SUI were identified. Baseline penile and finger peripheral oxygen saturation (SpO2), three-hour pad weight, 24-hour pad count and patient-reported outcomes (ICIQ-UI, QoL) were measured. Participants were then fitted with the PaceyCuff, and reassessed immediately, at three hours post-application and (via telephone) after two weeks. Results 13 men (average age 74, range 62–82) were recruited. ICIQ-UI scores decreased from 17 to 10, and QoL scores from 13 to 9. Average three-hour pad weight dropped from 94 g to 10 g and daily pad usage decreased from 4 to 0.9 pads. Participants reported good tolerance, with an average pain score of 1.8/10 and only 2 minor adverse effects (skin abrasion, transient pain). Penile SpO2 remained stable before, immediately after, and three hours post-use (76%, 82%, and 81% respectively). Sub-group analysis of patients over the age of 80 (n = 4) confirmed equal effectiveness. (ICIQ-UI decreased 18 to 10, QoL decreased 13 to 9, three-hour pad weight decreased 77 g to 9 g, daily pad usage decreased 4 to 1.5 pads, average pain 1.5/10). Conclusions The PaceyCuff has demonstrated both efficacy and tolerability in managing SUI in a UK cohort for the first time and offers a potential treatment option for elderly patients who are ineligible for surgical intervention.

The Usefulness of Vascularized Flap Craniotomy for Open-Wound Depressed Skull Fractures

BACKGROUND AND IMPORTANCE: Free bone flap craniotomy for open-wound depressed skull fractures poses a high risk of infection due to free bone fragments. This risk escalates in the presence of compound fractures with accompanying dural injuries. The primary objectives in managing depressed skull fractures include infection prevention and the correction of cosmetic deformities. This report describes the efficacy of vascularized flap craniotomy, which preserves blood flow to bone fragments, in reducing infection risks. CLINICAL PRESENTATION: In this study, we present a 54-year-old man with a head injury and a Glasgow Coma Scale score of 8. He had an open wound in the left parietal temporal area and depressed skull fractures with compound bone fragments. The patient underwent vascularized flap craniotomy, focusing on maintaining blood supply to the bone fragments, resulting in successful wound healing without acute infections. CONCLUSION: Vascularized flap craniotomy is an effective surgical option for treating open-wound depressed skull fractures, potentially reducing the risk of infection by maintaining blood flow to bone fragments. Further studies are required to validate its efficacy in larger patient populations.

Abstract 009: Prototyping a Novel Balloon‐Stent Device for Treating Brain Aneurysms

Introduction Although neurointerventional technologies have advanced for aneurysms, current adjunctive devices such as stents and temporary balloons still present significant limitations. Balloons can provide a uniform surface and neck protection for improved coiling and embolic placement, but also occlude parent artery blood flow and increase the risk of intraoperative ischemia and thrombus formation. Further, their inflation and deflation processes often result in diffuse vessel trauma. Stent technologies can support the parent vessel at the aneurysm, but coils placed behind the stent during aneurysm treatment can become entangled. Additionality, permanent stent placement necessitates long‐term dual antiplatelet therapy (DAPT), presenting substantial bleeding risks to the patient. This project aimed to develop, build, and validate the Balloon‐Mesh (BM), a unique endovascular device that enhances aneurysm neck protection during embolic device placement while maintaining blood flow in the parent artery distal to the aneurysm. Doing so minimizes the risk of ischemia while providing excellent aneurysm neck protection, setting it apart from existing solutions. Aim 1 was to design and build BM prototypes for endovascular aneurysm treatment. Aim 2 was to assess the BM prototype in an in vitro aneurysm blood flow model. The impact of this study illustrates how a high‐density mesh device could be superior to current adjunctive devices, improving post‐operative outcomes and signaling a paradigm shift in stent‐assisted embolization technology. Methods Aim 1 Pressure drop across neurovascular stenosis greater than 25% is an ischemic risk. Fluid simulations showed that a BM device with a pore size of 200 does not pose significant ischemic risk while providing superior aneurysm neck protection. From simulations, three initial BM devices were created. They were designed to be self‐expanding, retrievable, and balloon‐shaped. Each prototype evaluated a different profile to identify the optimal shape for neck protection. Aim 2 The BM prototypes were deployed in aneurysm models with real‐time pressure recording. Fluoroscopy was utilized to visualize flow and record any variations or complications that might arise during device deployment. The prototype performance was directly compared to a control device (Pipeline Medtronic). Aneurysm neck coverage was evaluated through contrast injections. Results All BM prototypes were successfully tracked and deployed at the neck of the aneurysm. Flow analysis shows the BM does not pose an ischemic risk. Fluoroscopy indicates the control device did not significantly reduce the flow inside the aneurysm. By comparison, the BM prototypes significantly reduced flow into and out of the aneurysm while maintaining parent artery flow. Conclusion This project delivered on Aims 1 and 2 by developing three BM prototypes that optimized aneurysm neck protection while maintaining parent artery blood flow. The device performance was validated using multiple in vitro vessel models. We found that the BM successfully protected the neck of an aneurysm while maintaining parent artery blood flow, eliminating ischemic risk. Additionally, the BM prototypes outperformed the control at minimizing flow into the aneurysm. Future work includes modifying the BM size for various vessels, investigate compatibility with embolic devices (coil/liquid), and in vivo testing in preparation for an FDA submission.

Vascularized bone grafts in spinal reconstruction: An updated comprehensive review

In the past two decades, plastic surgeons have advanced to the forefront of spinal surgery, joining orthopedic and neurosurgeons in the multidisciplinary field of spino-plastics. As the global disease burden grows with an increased incidence of spinal pathologies, vascularized bone grafts (VBGs) define the current frontier of spino-plastic surgery. Vascularized bone grafting involves lifting segments of bone with the muscular attachments but without the inclusion of a named vessel. When compared to traditional nonvascular bone grafts and allografts, VBGs have come forward as a favored technique for complex spinal reconstruction due to the unique opportunity to capitalize on the relationship between the tendons and Sharpey's fibers which maintain blood flow to both the bone and muscular segments. This technique ensures robust autologous tissue rearrangement and also takes advantage of the osteoinductive properties of the bone segments, promoting adequate structural support and the perfusion necessary for efficient direct healing and fusion in intricate spine reconstructions. Another one of the many favorable qualities of VBGs is the diversity of sources available to surgeons. The review explores the role of VBGs in enhancing spinal fusion rates and minimizing morbidity compared to traditional approaches. Additionally, a detailed examination of six common VBG sources-the iliac crest, ribs, medial scapula, occiput, spinous processes, and clavicle is included, highlighting each graft's specific techniques and emphasizing the range of options available to spino-plastic surgeons.

PROGRESS OF RESUSCITATIVE ENDOVASCULAR BALLOON OCCLUSION OF THE AORTA IN PREHOSPITAL EMERGENCY TREATMENT FOR PELVIC FRACTURE.

Pelvic fractures are severe traumatic injuries often accompanied by potentially fatal massive bleeding. Rapid control of hemorrhages in prehospital emergency settings is critical for improving outcomes in traumatic bleeding. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a promising technique for controlling active bleeding from pelvic fractures. By inserting a balloon catheter into the aorta, REBOA helps maintain blood flow to vital organs such as the brain and heart. This paper provides a comprehensive overview of the initial management of noncompressive trunk hemorrhage caused by pelvic fractures, introduces the technical principles and developments of REBOA, and explores its extensive application in prehospital emergency care. It delves into the operational details and outlines strategies for effectively managing potential complications. We aim to offer a theoretical framework for the future utilization of REBOA in managing uncontrollable hemorrhage associated with pelvic fractures in prehospital emergencies.

IMPROVEMENT OF CAPILLAROSCOPY METHOD FOR STUDYING HUMAN MICROCIRCULATION

The human circulatory system has historically captivated researchers in the field of medicine. Modern medicine, however, has moved beyond identifying a single crucial element, such as the heart or venous system, for maintaining blood flow. Instead, it emphasizes a more analytical approach, focusing on the interconnected functioning of all components within the system. The aim of this work is to analyze the existing methods of studying blood microcirculation and to improve the technology of capillaroscopy, technical means of raster microphotography to determine the physiological state and disorders of capillary circulation. To achieve this objective, we address the following tasks: analyzing existing non-invasive methods for studying the human vascular system; enhancing the optical capillaroscopy method through the utilization of modern high-resolution digital cameras, computer, and multimedia equipment, along with appropriate software for analyzing electronic images; developing a technological scheme and equipment design for digital microphotography of capillaries in the periungual region of the upper extremities; providing software solutions for registering and analyzing digital microphotographic images obtained through capillaroscopy; conducting experimental studies to explore the structure and properties of capillaries utilizing the developed technologies and equipment. Magnetic resonance imaging (MRI) enables the comprehensive evaluation of both anatomical and functional aspects of blood flow. Magnetic resonance angiography (MRA) capitalizes on the distinction between the signal emitted by moving tissue (blood) and that of surrounding stationary tissue, facilitating the acquisition of vascular images without the need for radiopaque contrast agents. Ultrasonography integrates Doppler and conventional ultrasound techniques, providing physicians with insights into blood vessel structure and blood flow dynamics. Traditional ultrasound employs sound waves that are imperceptible to the human ear and bounce off blood vessels, while Doppler ultrasound measures the velocity of sound wave reflection from moving elements. Ophthalmoscopy constitutes a fundamental component of standard ophthalmological examinations, serving as a pivotal tool for diagnosing eye conditions and evaluating the condition of blood vessels. Additionally, ophthalmoscopy aids in diagnosing autoimmune disorders. Capillaroscopy enables comprehensive assessments of both systemic and regional microcirculation disorders, facilitating the characterization of tissue metabolism. Dysfunction in capillary function contributes to circulatory impairments, leading to blood stasis, metabolic irregularities, and compromised immunity, thereby exacerbating existing conditions and predisposing individuals to new diseases. Optical computerized capillaroscopy offers a non-invasive means of visualizing, examining, and archiving capillary images, enabling clinicians to make informed assessments regarding blood microcirculation. Experimental validation of the optimized hardware and software capillaroscopy system was conducted using nail bed capillaries of a patient with type II diabetes mellitus undergoing insulin therapy for 10 years. This study underscores the importance of refining and enhancing optical capillaroscopy methodologies by leveraging high-resolution camera sensors and modern computational tools for image processing.

Link between Yoga and Heart Rate Variability: Can Yoga Enhance the Cardiac Resonance.

Cardiac resonance is a complicated phenomenon involving the coordinated oscillations of numerous circulatory system components, such as electrical activity, contraction and relaxation, and blood flow. It is critical for the normal functioning of the heart and for maintaining blood flow throughout the body. Cardiac resonance is defined as a series of tiny waves produced by the heartbeat and overlaid on flow data and airway pressures. A variety of technologies, including cardiac magnetic resonance (CMR) imaging, can be used to identify these waves. CMR is a strong noninvasive method for seeing and quantifying heart anatomy and function in great detail. CMR can be used to assess cardiac resonance in both healthy and heart disease patients. A regular and coordinated pattern of oscillations characterizes cardiac resonance in healthy persons. In patients with heart illness, however, cardiac resonance can be interrupted, resulting in diminished cardiac function and decreased blood flow. The intricate role of cardiac resonance in cardiac health and disease is continuously being studied by researchers. However, it is obvious that cardiac resonance is an exciting area of research that has the potential to change the way to identify and treat heart illness. Yoga is a mind-body practice that has been demonstrated to have numerous cardiovascular health advantages, such as improved heart function, reduced inflammation, and lower blood pressure. Yoga is hypothesized to promote cardiac resonance by encouraging coordinated oscillations of numerous cardiovascular system components. Various researches have shown buoyant results such as yoga can be helpful in improving heart rate variability, cardiac resonance and reducing arterial stiffness. Stress can disrupt cardiac resonance and increase the risk of heart disease. More research is needed to completely understand the mechanisms that impact cardiac resonance and the long-term advantages of yoga for heart health.

Ultrasound images of the ascending aorta of anesthetized northern fur seals and Steller sea lions confirm that the aortic bulb maintains continuous blood flow.

The increased size and enhanced compliance of the aortic bulb-the enlargement of the ascending aorta-are believed to maintain blood flow in pinnipeds during extended periods of diastole induced by diving bradycardia. The aortic bulb has been described ex vivo in several species of pinnipeds, but in vivo measurements are needed to investigate the relationship between structure and function. We obtained ultrasound images using electrocardiogram-gated transesophageal echocardiography during anesthesia and after atropine administration to assess the relationship between aortic bulb anatomy and cardiac function (heart rate, stroke volume, cardiac output) in northern fur seals (Callorhinus ursinus) and Steller sea lions (Eumetopias jubatus). We observed that the aortic bulb in northern fur seals and Steller sea lions expands during systole and recoils over the entire diastolic period indicating that blood flow is maintained throughout the entire cardiac cycle as expected. The stroke volumes we measured in the fur seals and sea lions fit the values predicted based on body size in mammals and did not change with increased heart rates, suggesting that greater stroke volumes are not needed for aortic bulb function. Overall, our results suggest that peripheral vasoconstriction during diving is sufficient to modulate the volume of blood in the aortic bulb to ensure that flow lasts over the entire diastolic period. These results indicate that the shift of blood into the aortic bulb of pinnipeds is a fundamental mechanism caused by vasoconstriction while diving, highlighting the importance of this unique anatomical adaptation.

Effect of HHFNC therapy on organ oxygenation and brain metabolism in neonates receiving exchange transfusion.

Exchange transfusion therapy is a complex and invasive procedure with a high risk coefficient. This method involves replacing the entire blood of a child with fresh blood with double circulating blood volume in a short period, typically in 1-2 h. This procedure can cause the body's internal environment to be unstable, which can put newborns under a lot of stress. This stress can lead to many, including abnormal laboratory biochemical examination, low or high blood pressure, and apnea. There is also the possibility of secondary infection and, in severe cases, cardiac arrest. This study investigated the effects of Humidified high-flow nasal cannula (HHFNC) ventilation on hemodynamic stability and oxygenation during exchange transfusion in neonates. Furthermore, the effects on brain metabolism and salivary cortisol during exchange transfusion were also analyzed. In this study, the control group consisted of 45 cases of children who underwent simple blood exchange between 1 May 2017, and 31 December 2019 control group. The observation group consisted of 33 cases of children who underwent blood exchange under HHFNC support between 1 January 2020, and 30 April 2022. The study compared various physiological parameters between the control and the observation group. These included blood gas analysis, pulmonary artery pressure, ejection fraction, invasive mean arterial pressure, heart rate, cerebral oxygenation, intestinal oxygenation, renal oxygenation, and duration of blood exchange. Furthermore, the study also compared the changes in brain metabolic and salivary cortisol indicators between the two groups of children. The results did not reveal any significant difference in PH, PaO2, and duration of blood exchange between the control and the observation group. However, the observation group's invasive mean arterial pressure, ejection fraction, cerebral oxygenation, intestinal oxygenation, and renal oxygenation were higher than those of the control group. Furthermore, compared with the control group, the pulmonary artery pressure, heart rate, and PaCO2 were lower in the observation group. There was a statistically significant difference between the two groups of children in the relevant clinical indicators (total bilirubin, hemoglobin, SPO2, etc.) after exchange transfusion. After 1 h of blood exchange and after blood exchange, the salivary cortisol levels of the observation group were lower than the control group. The difference was statistically significant. The NAA/Cho and Cho/Cr values of the two groups of children were also significantly different. During blood exchange, unstable hemodynamics substantially impact organ oxygenation. The results of this study suggest that HHFNC and specific ventilation pressure support can improve the respiratory rate and help maintain blood flow stability and organ oxygenation. This technique can also reduce adverse reactions caused by blood exchange, minimizing patient stress and reducing the impact on brain metabolism.

Sex-dependent impact of a short rest after lunch on hemodynamics as assessed by Doppler sonography.

Taking a short rest after lunch suppresses increases in blood flow to the digestive organs and maintains blood flow to the brain in the afternoon, possibly providing beneficial effects in preventing post-prandial drowsiness. The present study investigated sex-dependent influences on changes in hemodynamics produced by taking a short rest after lunch. Subjects comprised 20 healthy young adults (10 men, 10 women; mean age 21 ± 1years). Doppler sonography was performed to measure blood flow in the superior mesenteric artery (SMA) and common carotid artery (CCA) before and after lunch every hour on each day, with and without a 15-min rest with eyes closed after lunch. Blood pressure and heart rate (HR) were also measured. For both men and women, peak systolic velocity (PSV) in the SMA was suppressed by taking a rest. PSV in the CCA in men was increased at 0.5h after lunch in the resting condition but was decreased in the non-resting condition (median 109%, interquartile range [IQR] 102-120% vs. median 98%, IQR 90-107%; P = 0.037). No such differences were observed in women. Although post-prandial increases in HR were observed in women, a similar increase was only found for men in the resting condition. An increase in CCA blood flow was observed only in men. The present study suggests that a short rest after lunch could better promote the maintenance of blood flow to the brain in men than in women.

A computational program for automated surgical planning of fenestrated endovascular repair

An Abdominal Aortic Aneurysm (AAA) is a dilation of the aorta at the level of the abdomen. To reduce the risk of rupture, an endograft is often implanted inside the aneurysm to decrease pressure on the aneurysm sac. To maintain blood flow to major abdominal vessels, a fenestrated endograft can be used, whereby physicians modify commercial endografts by creating fenestrations based on preoperative computed tomography imaging. The manual process of aligning patient-specific visceral anatomy onto endografts can be tedious and subject to human error. Here we developed a computational program, ‘FenFit’, for automated fitting of fenestrations onto commercially available endografts. A pilot clinical study was conducted to evaluate the efficiency of FenFit compared to physician manual planning, showing FenFit can reduce planning time by 62-fold on average. Our program has potential to improve clinical outcomes by providing a user interface that is expeditious and far less susceptible to human error.

Percutaneous deep venous arterialization with balloon angioplasty salvaged a life‐threatening critical limb in a hemodialysis patient after repeated pedal angioplasty failed: A case report

AbstractChronic limb‐threatening ischemia (CLTI) with severe below‐the‐ankle (BTA) lesions is often difficult to revascularize with endovascular treatment (EVT) and surgical treatment. We present a case of successful limb salvage using percutaneous deep venous arterialization (pDVA) in a patient with CLTI whose BTA lesion reconstruction failed. A 57‐year‐old man with diabetes mellitus and end‐stage renal failure on maintenance hemodialysis was referred to our hospital because of gangrene in the second and third toes of his left foot. EVT was repeated for the anterior tibial artery, posterior tibial artery (PTA), dorsal foot artery, and plantar artery lesions; however, revascularization below the ankle was unsuccessful. As the infection had spread to the sole of the foot, below‐the‐knee amputation was indicated, but the patient refused. Therefore, we performed pDVA on the left PTA simultaneously with a Lisfranc amputation. An arteriovenous fistula was created at the ankle joint using a Venous Arterialization Simplified Technique and a guidewire was inserted into the plantar vein. Balloon dilatation from PTA to the plantar vein was performed to complete the pDVA. Although repeated EVT was required to maintain blood flow in the pDVA, skin grafting was performed 3 months after the pDVA, the wound completely healed, and he was discharged 6 months after the DVA. The pDVA can be an option for limb salvage in patients with no‐option CLTI who are confronted by imminent amputation.

Clinical Significance of the Interposition Graft for Reconstruction Between the Common Hepatic Artery and Gastroduodenal Artery for Arterial Patency of the Pancreas Graft in Pancreas Transplantation

Due to the limited number of organ donations from deceased donors in Japan, pancreas grafts for pancreas transplantation (PTx) are frequently harvested from the donor in the same donation surgery as the liver graft. In such a situation, the common hepatic artery (CHA) and gastroduodenal artery (GDA) are dissected, resulting in decreased blood flow to the head of the pancreas graft. Therefore, GDA reconstruction using an interposition graft (I-graft) between the CHA and GDA has been traditionally performed to maintain blood flow. This study investigated the clinical significance of GDA reconstruction with the I-graft regarding the arterial patency of the pancreas graft in patients after PTx. Fifty-seven patients underwent PTx for type 1 diabetes mellitus at our hospital between 2000 and 2021. Twenty-four cases in which GDA reconstruction was performed using the I-graft and artery blood flow of the pancreas graft was evaluated by contrast-enhanced computed tomography or angiography were included in this study. The patency of the I-graft was 95.8%, and only one patient had a thrombus in the I-graft. Nineteen patients (79.2%) had no thrombus in the artery of the pancreas graft; the other five cases had thrombus in the superior mesenteric artery (SMA). The patient with the thrombus in the I-graft required graftectomy for the pancreas graft. The patency of the I-graft was favorable. Furthermore, the clinical significance of the GDA reconstruction with the I-graft is suggested to maintain blood flow in the pancreas head if the SMA is occluded.

Two-step arterial reconstruction technique for en bloc resection of a large retroperitoneal liposarcoma involving the common iliac artery.

Retroperitoneal liposarcoma (RPLS) is a rare but challenging neoplasm, which is frequently associated with iliac vessel invasion. We describe how we used a two-step arterial reconstruction technique to perform en bloc resection of a large RPLS involving the iliac arteries in three patients. A temporal long in situ graft bypass was established using a prosthetic vascular graft during dissection of the tumor. This bypass provided an unobscured surgical field, while maintaining blood flow in the lower limb during the operation. After removal of the tumor and washing out the abdominal cavity, the new prosthetic vascular graft of a suitable length was placed. No graft-related complications, including vascular graft infection or graft occlusion, occurred during the follow-up period. This novel technique appears to provide a safe and effective way to remove large RPLSs involving the retroperitoneal major vessels.

Alternative position of cannulae in veno-venous extracorporeal membrane oxygenation for maintaining sufficient flow support

Blood flow disturbance of veno-venous extracorporeal membrane oxygenation (VV-ECMO) can be a risk factor of weaning failure. We report an alternative position of cannulae of VV-ECMO which can maintain blood flow. The recirculation rate could be controlled by adjusting a position of return cannula using dilutional ultrasound monitoring.

Orthotopic implantable liver decellularized scaffold for acute liver failure

• The natural morphology of the decellularized constructs is preserved by whole liver perfusion decellularization technique. • The whole liver perfused decellularized scaffold exhibit a superior bio-mechanical and histocompatibility. • Orthotopic implantable liver recellularized scaffold show excellent hepatic functions in vivo. Decellularized scaffolds have an irreplaceable role in the development of tissue engineering. Challenges in this field are concentrated on shaping macro-scale constructs and maintaining blood flow. Here, we establish a whole liver perfused decellularized scaffold cultured with hepatocytes for transplantable bioengineered liver construction. Owing to retained intact gross morphology of liver, geometric structure and biomechanical environment can support whole liver lobe transplantation. Besides, unremoved extracellular matrix (ECM) and vascular networks can delivery continuous nutrient for cell adhesion. Based on recellularized bioengineering liver scaffold, we have demonstrated its excellent hepatic functions when it orthotopic implanted in acute liver failure (ALF) rats, along with the prolonged survival rate and improved biochemical indicators. These outstanding properties indicate that the orthotopic implantable liver scaffold has broad clinical application prospects in the treatment of ALF and other regeneration diseases. A whole liver perfused decellularized scaffold cultured with hepatocytes for transplantable bioengineered liver construction.

Hemostasis in the Pregnant Woman, the Placenta, the Fetus, and the Newborn Infant.

The hemostasis system is composed of procoagulant, anticoagulant, and fibrinolytic proteins that interact with endothelial and blood cells and with each other in a complex system of checks and balances to maintain blood flow while preventing both hemorrhage and thrombosis. Pregnancy is a unique physiological state in which biological alterations predispose both mother and fetus to both bleeding and clotting. The placenta is a vascular interface for maternal and fetal blood exchange which predisposes the mother to hemorrhage. Maternal hemostasis presents a compensatory hypercoagulability including elevated factor VIII, von Willebrand factor, fibrinogen and thrombin generation, decreased thrombin regulation with resistance to activated protein C and decreased free protein S, and decreased fibrinolysis with increased plasminogen activator inhibitors. The placental vascular surface is of fetal trophoblastic origin that derives many characteristics of endothelium but differs in that tissue factor is constitutively expressed. Ontogeny of fetal hemostasis is characteristic. Platelets, von Willebrand factor, factor VIII, and fibrinogen are expressed and mature early in gestation, while vitamin K-dependent and contact factors exhibit delayed development. The fetal hemostatic system has a decreased capacity to generate or regulate thrombin, resulting in a fragile balance with little capacity to compensate under stress conditions, particularly in the infant born prematurely. Dysfunction of the maternal/placental/fetal unit gives rise to gestational disorders including preeclampsia, fetal growth restriction, placental abruption, and premature delivery. Knowledge of normal hemostasis levels and function are critical to evaluate bleeding or clotting syndromes in the pregnant woman and her fetus or newborn infant.

Rodent Model for Orthotopic Implantation of Engineered Liver Devices.

This study presents a novel surgical model developed to provide hematological support for implanted cellularized devices augmenting or replacing liver tissue function. Advances in bioengineering provide tools and materials to create living tissue replacements designed to restore that lost to disease, trauma, or congenital deformity. Such substitutes are often assembled and matured in vitro and need an immediate blood supply upon implantation, necessitating the development of supporting protocols. Animal translational models are required for continued development of engineered structures before clinical implementation, with rodent models often playing an essential early role. Our long-term goal has been generation of living tissue to provide liver function, utilizing advances in additive manufacturing technology to create 3D structures with intrinsic micron to millimeter scale channels modeled on natural vasculature. The surgical protocol developed enables testing various design iterations in vivo by anastomosis to the host rat vasculature. Lobation of rodent liver facilitates partial hepatectomy and repurposing the remaining vasculature to support implanted engineered tissue. Removal of the left lateral lobe exposes the underlying hepatic vasculature and can create space for a device. A shunt is created from the left portal vein to the left hepatic vein by cannulating each with separate silicone tubing. The device is then integrated into the shunt by connecting its inflow and outflow ports to the tubing and reestablishing blood flow. Sustained anticoagulation is maintained with an implanted osmotic pump. In our studies, animals were freely mobile after implantation; devices remained patent while maintaining blood flow through their millifluidic channels. This vascular anastomosis model has been greatly refined during the process of performing over 200 implantation procedures. We anticipate that the model described herein will find utility in developing preclinical translational protocols for evaluation of engineered liver tissue. Impact statement Tissue and organ transplantation are often the best clinically effective treatments for a variety of human ailments. However, the availability of suitable donor organs remains a critical problem. Advances in biotechnology hold potential in alleviating shortages, yet further work is required to surgically integrate large engineered tissues to host vasculature. Improved animal models such as the one described are valuable tools to support continued development and evaluation of novel therapies.

THE EFFECT OF SHORT DURATION BED REST AND TYPE 2 DIABETES MELLITUS ON ARTERIAL STRUCTURE AND FUNCTION IN OLDER ADULTS

Abstract Type 2 diabetes mellitus (T2DM) and inactivity individually accelerate changes related to vascular aging. These changes increase cardiovascular risk and contribute to morbidity and mortality in the elderly. It is unknown if T2DM and bed rest have an additive, deleterious effect on vascular structure and function in older adults. The objective of this study is to determine the magnitude of the effect of bed rest on vascular structure in older adults with T2DM compared to healthy controls and determine if resistance exercise is protective of this effect. So far, we have recruited T2DM (n=9) and healthy control (n=17) subjects (age: 67.0 ± 6.7 years) to undergo five days of bed rest. During bed rest, subjects were randomized to receive intensive bedside resistance exercise physical therapy or standard of care in-bed passive physical therapy. On bed rest days 1 and 5, popliteal artery diameter, area, blood velocity, and blood flow were measured using Doppler ultrasonography. Our preliminary data show that the T2DM, non-exercise group had significantly greater decreases in popliteal artery diameter (-0.59 mm ± 0.18) than the control, non-exercise group (-0.17 mm ± 0.11). Resistance exercise did not prevent artery size changes in either controls or T2DM. Resistance exercise showed a trend in preventing blood velocity and flow reduction in both T2DM and control groups. These preliminary data suggest that older adults with T2DM had greater structural popliteal artery changes compared to controls. Resistance exercise appears to help maintain blood flow by maintaining/increasing popliteal artery blood velocity, but not size.

High versus low blood pressure targets for cardiac surgery while on cardiopulmonary bypass.

Cardiac surgery is performed worldwide. Most types of cardiac surgery are performed using cardiopulmonary bypass (CPB). Cardiac surgery performed with CPB is associated with morbidities. CPB needs an extracorporeal circulation that replaces the heart and lungs, and performs circulation, ventilation, and oxygenation of the blood. The lower limit of mean blood pressure to maintain blood flow to vital organs increases in people with chronic hypertension. Because people undergoing cardiac surgery commonly have chronic hypertension, we hypothesised that maintaining a relatively high blood pressure improves desirable outcomes among the people undergoing cardiac surgery with CPB. To evaluate the benefits and harms of higher versus lower blood pressure targets during cardiac surgery with CPB. We used standard, extensive Cochrane search methods. The latest search of databases was November 2021 and trials registries in January 2020. We included randomised controlled trials (RCTs) comparing a higher blood pressure target (mean arterial pressure 65 mmHg or greater) with a lower blood pressure target (mean arterial pressure less than 65 mmHg) in adults undergoing cardiac surgery with CPB. We used standard Cochrane methods. Primary outcomes were 1. acute kidney injury, 2. cognitive deterioration, and 3. all-cause mortality. Secondary outcomes were 4. quality of life, 5. acute ischaemic stroke, 6. haemorrhagic stroke, 7. length of hospital stay, 8. renal replacement therapy, 9. delirium, 10. perioperative transfusion of blood products, and 11. perioperative myocardial infarction. We used GRADE to assess certainty of evidence. We included three RCTs with 737 people compared a higher blood pressure target with a lower blood pressure target during cardiac surgery with CPB. A high blood pressure target may result in little to no difference in acute kidney injury (risk ratio (RR) 1.30, 95% confidence interval (CI) 0.81 to 2.08; I² = 72%; 2 studies, 487 participants; low-certainty evidence), cognitive deterioration (RR 0.82, 95% CI 0.45 to 1.50; I² = 0%; 2 studies, 389 participants; low-certainty evidence), and all-cause mortality (RR 1.33, 95% CI 0.30 to 5.90; I² = 49%; 3 studies, 737 participants; low-certainty evidence). No study reported haemorrhagic stroke. Although a high blood pressure target may increase the length of hospital stay slightly, we found no differences between a higher and a lower blood pressure target for the other secondary outcomes. We also identified one ongoing RCT which is comparing a higher versus a lower blood pressure target among the people who undergo cardiac surgery with CPB. A high blood pressure target may result in little to no difference in patient outcomes including acute kidney injury and mortality. Given the wide CIs, further studies are needed to confirm the efficacy of a higher blood pressure target among those who undergo cardiac surgery with CPB.