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Tracking Fibrinolysis of Chandler Loop-Formed Whole Blood Clots Under Shear Flow in An In-Vitro Thrombolysis Model

Thromboembolism and related complications are a leading cause of morbidity and mortality worldwide and various assays have been developed to test ...

Indiana University School of Medicine

Given that smoking is known to contribute to gastrojejunal anastomotic (GJA) ulcers, cessation is recommended prior to laparoscopic Roux-en-Y gastric bypass (LRYGB). However, smoking relapse rates and the exact ulcer risk remain unknown. This study aimed to define smoking relapse, risk of GJA ulceration, and complications after LRYGB.

High Rates of Nicotine Use Relapse and Ulcer Development Following Roux-en-Y Gastric Bypass.

Conducting in-vitro thrombosis research presents numerous challenges, the primary of which is working with blood products, whether whole blood or fractionated whole blood, that have limited functional shelf-lives. As a result, being able to significantly prolong the clotting functionality of whole blood via fractionation and recombination promises greater accessibility via resource minimization in the realm of thrombosis research. Whole blood with CPDA1 from healthy volunteers was fractionated and stored as frozen platelet-free plasma (PFP, -20°C), refrigerated packed red blood cells (pRBCs, 4°C) and cryopreserved platelets (-80°C). Subsequent recombination of the above components into their native ratios were tested via thromboelastography (TEG) to capture clotting dynamics over a storage period of 13 weeks in comparison to refrigerated unfractionated WB+CPDA1. Reconstituted whole blood utilizing PFP, pRCBs and cryopreserved platelets were able to maintain clot strength (maximum amplitude) akin to day-0 whole blood even after 13 weeks of storage. Clots formed by reconstituted whole blood exhibited quicker clotting dynamics with nearly two-fold shorter R-times and nearly 1.3-fold increase in fibrin deposition rate as measured by TEG. Storage of fractionated whole blood components, in their respective ideal conditions, provides a means of prolonging the usable life of whole blood for in-vitro thrombosis research. Cryopreserved platelets, when recombined with frozen PFP and refrigerated pRBCs, are able to form clots that nearly mirror the overall clotting profile expected of freshly drawn WB.

In-vitro thromboelastographic characterization of reconstituted whole blood utilizing cryopreserved platelets.

Long-term anticoagulation in the treatment of Cerebral Venous Sinus Thrombosis (CVST) has revolved around the use of warfarin. The relatively recent introduction of Direct Oral Anticoagulants (DOACs), such as Factor Xa inhibitors, in treating CVSTs promises to offer numerous patient benefits. We aimed to examine the efficacy of Factor Xa inhibitors in comparison to warfarin in the long-term treatment of CVSTs. A single-center retrospective analysis was conducted in which 49 eligible patients having presented with a first-time CVST were identified. Long-term anticoagulation was achieved with Warfarin (n = 23) or Factor Xa Inhibitors (n = 26; Apixaban or Rivaroxaban). Outcomes of interest were improvements in patient functional status, modified Ranking Scores (mRS), and radiographic improvement/resolution in sinus thromboses. Secondary comparisons included complication rates, particularly recurring venous thrombotic events. Patient mRS scores by 7-to-18-month follow-up all fell within the extremely favorable range of 0-1 regardless of the long-term anticoagulant (P-value = 0.3591). Proportion of patients with radiographic improvement/resolution of thrombosed sinuses trended towards being higher in the Factor Xa Inhibitor group at the <12-month period, 69.2%, compared to 33.3% with Warfarin (-value = 0.0548). By the >12-month follow-up period, Warfarin and Factor Xa inhibitor groups had similar rates of radiographic sinus improvement - 76.9% versus 71.4%, respectively (-value = 0.6298). No statistically significant differences were documented between groups regarding complications. Factor Xa inhibitors are equally as effective as Warfarin in the long-term treatment of CVSTs, whether it be restoring patient functional status, sinus thrombus burden reduction, or minimizing bleeding complications whilst preventing recurrent venous thrombosis.

Warfarin versus factor Xa inhibitors in the long-term treatment of cerebral venous sinus thrombosis a single-center retrospective analysis.

Sugammadex reversal of neuromuscular blocking agents (NMBAs) is usually performed postoperatively. A scarcity of literature exists exploring sugammadex use for timely neurological examination of neurosurgical patients. NMBAs, like rocuronium, are used in the Emergency Department during intubation and their unpredictable duration of action often impedes timely and accurate assessment of patient neurological status. We aim to explore the role of sugammadex in evaluating patients in need of acute neurosurgical care.

Utility of neuromuscular blockade reversal in the evaluation of acute neurosurgical patients: A retrospective case-series.

Thrombosis can lead to a wide variety of life-threatening circumstances. As current thrombolytic drug screening models often poorly predict drug profiles, leading to failure of thrombolytic therapy or clinical translation, more representative clot substrates are necessary for drug evaluation. Utilizing a Chandler loop device to form clot analogs at high shear has gained popularity in stroke societies. However, shear-dependent clot microstructure has not been fully addressed and low shear conditions are often overlooked. We herein characterized the impact of wall shear rate (126 to 951 s) on clot properties in the Chandler loop. Different revolutions (20-60) per minute and tubing sizes (3.2 to 7.9 mm) were employed to create different sized clots to mimic various thrombosis applications. Increased shear resulted in decreased RBC counts (76.9 ± 4.3% to 17.6 ± 0.9%) and increased fibrin (10 to 60%) based on clot histology. Increased fibrin sheet morphology and platelet aggregates were observed at higher shear under scanning electron microscope. These results show the significant impact of shear and tubing size on resulting clot properties and demonstrate the capability of forming a variety of reproducible in-vivo-like clot analogs in the Chandler loop device controlling for simple parameters to tune clot characteristics.

Effect of Chandler loop shear and tubing size on thrombus architecture.

A great need exists for the development of a more representative in-vitro model to efficiently screen novel thrombolytic therapies. We herein report the design, validation, and characterization of a highly reproducible, physiological scale, flowing clot lysis platform with real-time fibrinolysis monitoring to screen thrombolytic drugs utilizing a fluorescein isothiocyanate (FITC)-labeled clot analog. Using this Real-Time Fluorometric Flowing Fibrinolysis assay (RT-FluFF assay), a tPa-dependent degree of thrombolysis was observed both via clot mass loss as well as fluorometrically monitored release of FITC-labeled fibrin degradation products. Percent clot mass loss ranged from 33.6% to 85.9% with fluorescence release rates of 0.53 to 1.17 RFU/min in 40 and 1000 ng/mL tPa conditions, respectively. The platform is easily adapted to produce pulsatile flows. Hemodynamics of human main pulmonary artery were mimicked through matching dimensionless flow parameters calculated using clinical data. Increasing pressure amplitude range (4-40 mmHg) results in a 20% increase of fibrinolysis at 1000 ng/mL tPA. Increasing shear flow rate (205-913 s) significantly increases fibrinolysis and mechanical digestion. These findings suggest pulsatile level affects thrombolytic drug activities and the proposed in-vitro clot model offers a versatile testing platform for thrombolytic drug screening.

Real-time tracking of fibrinolysis under constant wall shear and various pulsatile flows in an in-vitro thrombolysis model.

This study investigates the influence of microplastics on blood clotting. It addresses the lack of comprehensive research on the effects of microplastic size and surface modification on clotting dynamics in human whole blood. Thromboelastography was used to examine aminated (aPS), carboxylated (cPS), and non-functionalized (nPS) polystyrene particles with sizes of 50, 100, and 500  nm. Results show that cPS consistently activated the clotting cascade, demonstrating increased fibrin polymerization rates, and enhanced clot strength in a size and concentration-dependent manner. nPS had minimal effects on clotting dynamics except for 50  nm particles at the lowest concentration. The clotting effects of aPS (100  nm particles) resembled those of cPS but were diminished in the 500  nm aPS group. These findings emphasize the importance of microplastic surface modification, size, concentration, and surface area on  whole blood clotting dynamics.

Exploring microplastic impact on whole blood clotting dynamics utilizing thromboelastography.

In patients with pituitary adenomas, incidental intracranial aneurysms have been documented. Previous studies have highlighted the importance of preoperative imaging in these patients. However, imaging may be limited and fail to show the presence of vascular abnormalities. In this report, we discuss a case of a man in his 30s presenting with a newly diagnosed pituitary adenoma. CT and MRI, on admission, showed a pituitary mass with extension into the right cavernous sinus. After a sudden neurological deterioration, emergent CT/CT angiography revealed pituitary apoplexy with subarachnoid extension without vascular abnormalities. Successful emergency transsphenoidal hypophysectomy was followed by digital subtraction angiography which revealed the presence of two right supraclinoid internal carotid artery aneurysms. With this case, we aim to highlight the need for further vascular imaging in patients with pituitary apoplexy and subarachnoid haemorrhage, as preoperative imaging may be negative for vascular abnormalities especially in the setting of cavernous sinus invasion.

Subarachnoid haemorrhage associated with pituitary apoplexy and radiographically occult supraclinoid internal carotid artery aneurysms.

Bariatric clinical calculators have already been implemented in clinical practice to provide objective predictions of complications and outcomes. The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Surgical Risk/Benefit Calculator is the most comprehensive risk calculator in bariatric surgery.

Does the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program bariatric risk/benefit calculator hold its weight? An assessment of its accuracy.

After craniectomy, autologous bone flaps may be stored using wet or dry cryopreservation. After brain edema subsides, they are replaced during an operation termed cranioplasty. Cranioplasty is associated with 15% infection incidence.

Alexei Christodoulides

Department of Emergency Medicine

Indiana University School of Medicine

Tracking Fibrinolysis of Chandler Loop-Formed Whole Blood Clots Under Shear Flow in An In-Vitro Thrombolysis Model

Alexei Christodoulides

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Emergency Medicine

Indiana University School of Medicine

Tracking Fibrinolysis of Chandler Loop-Formed Whole Blood Clots Under Shear Flow in An In-Vitro Thrombolysis Model

Department of Emergency Medicine