Background: While it is well recognized that different biomaterials induce thrombosis at low shear rates, the effect of high shear rates may be quite different. We hypothesize that the amount of thrombus formation on a given material can be greatly influenced by the local shear rate.Methods: We tested this hypothesis with two different whole blood perfusion loop assays to quantify biomaterial thrombogenicity as a function of shear stress.One assay uses obstructive posts (pins) of material positioned centrally in a tube perfused at high shear rate of >5000/s for 24 h. A second assay uses a parallel plate chamber to perfuse low (<150/s), medium (~500/s), and high shear rates over 96 h. We evaluated the thrombogenicity of seven different biomaterials including stainless steel, acrylic, ceramic, Dacron, polytetrafluoroethylene (PTFE), silicone, and polyvinyl chloride (PVC).Results: For the pin assay, thrombus mass was significantly greater for stainless steel than either zirconia ceramic or acrylic (p < 0.001). Similarly, the parallel plate chamber at high shear showed that steel and PTFE (p < 0.02) occluded the chamber faster than acrylic. In contrast, a low shear parallel plate chamber revealed that stainless steel and PTFE were least thrombogenic, while silicone, Dacron, and other plastics such as acrylic were most thrombogenic. Histology revealed that high shear thrombi had a large proportion of platelets not seen in the low shear fibrin-rich thrombi.
Conclusion:This differential thrombogenicity based on shear rate conditions may be important in the selection of biomaterials for blood-contacting devices.
Objective:
The aim of this study was to quantify and describe baseline patient and parent-proxy health-related quality of life scores in patients with low-flow vascular malformations at a single, tertiary-care vascular anomalies clinic.
Study design:
This is a retrospective study of data collected on patients with low-flow vascular malformations between the ages of 2 to 25 who were seen at a single, tertiary-care center vascular anomalies clinic. A total of 266 patients are included in this study.
Results:
Patients with lymphatic malformations report decreased quality of life scores as compared with venous malformations in the emotional, psychological, school, and social domains. Patients with lower extremity malformation report decreased quality of life scores as compared with head/neck, trunk, upper extremity, and multifocal malformations; most notably in the physical domain.
Conclusions:
Treatment of low-flow vascular malformations should aim to improve patient quality of life. The use of standardized health-related quality of life measures in this study quantifies baseline quality of life scores among patients with low-flow vascular malformations.
Objectives
To determine clinical course and outcomes in rheumatic disease patients with coronavirus disease 2019 (COVID-19) and compare results to uninfected patients.
Methods
We conducted a case cohort study of autoimmune disease patients with COVID-19 (confirmed by severe acute respiratory syndrome coronavirus 2 PCR) from 02/01/2020 to 07/31/2020 and compared them in a 1:3 ratio with uninfected patients who were matched based on race, age, sex, and comorbidity index. Patient demographics, clinical course, and outcomes were compared among these patient groups.
Results
A total of 70 rheumatic disease patients with COVID-19 (mean age, 56.6 years; 64% African American) were identified. The 34 (49%) patients who were hospitalized used oral glucocorticoids more frequently (p<0.01). All 10 patients on anti-TNFα medications were treated as outpatients (p<0.01). Those hospitalized with COVID-19 more often required ICU admission (17 (50%) vs 27 (26%), OR=2.78 (95% CI: 1.24 to 6.20)) and intubation (10 (29%) vs 6 (6%), OR=6.67 (95% CI: 2.20 to 20.16)) than uninfected patients. They also had higher mortality rates (6 (18%) vs 3 (3%), OR=7.21 (95% CI: 1.70 to 30.69)). Of the six COVID-19 patients who died, one was of African ancestry (p=0.03).
Conclusions
Rheumatic disease patients infected with COVID-19 were more likely to require ICU admission, ventilation, and died more frequently versus uninfected patients with autoimmune disease. Patients on anti-TNFα medications were hospitalized less frequently while those on chronic glucocorticoids were hospitalized more frequently. These findings have important implications for medication choice in rheumatic disease patients during the ongoing spread of COVID-19.
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