Viscoelastic testing reveals normalization of the coagulation profile 12 weeks after severe COVID-19.

COVID 19 is associated with a hypercoagulable state and frequent thromboembolic complications. For how long this acquired abnormality lasts potentially requiring preventive measures, such as anticoagulation remains to be delineated. We used viscoelastic rotational thrombelastometry (ROTEM) in a single center cohort of 13 critical ill patients and performed follow up examinations three months after discharge from ICU. We found clear signs of a hypercoagulable state due to severe hypofibrinolysis and a high rate of thromboembolic complications during the phase of acute illness. Three month follow up revealed normalization of the initial coagulation abnormality and no evidence of venous thrombosis in all thirteen patients. In our cohort the coagulation profile was completely normalized three months after COVID-19. Based on these findings, discontinuation of anticoagulation can be discussed in patients with complete venous reperfusion.

Thromboembolic complications in critically ill COVID-19 patients are associated with impaired fibrinolysis.

BACKGROUND: There is emerging evidence for enhanced blood coagulation in coronavirus 2019 (COVID-19) patients, with thromboembolic complications contributing to morbidity and mortality. The mechanisms underlying this prothrombotic state remain enigmatic. Further data to guide anticoagulation strategies are urgently required. METHODS: We used viscoelastic rotational thromboelastometry (ROTEM) in a single-center cohort of 40 critically ill COVID-19 patients. RESULTS: Clear signs of a hypercoagulable state due to severe hypofibrinolysis were found. Maximum lysis, especially following stimulation of the extrinsic coagulation system, was inversely associated with an enhanced risk of thromboembolic complications. Combining values for maximum lysis with D-dimer concentrations revealed high sensitivity and specificity of thromboembolic risk prediction. CONCLUSIONS: The study identifies a reduction in fibrinolysis as an important mechanism in COVID-19-associated coagulopathy. The combination of ROTEM and D-dimer concentrations may prove valuable in identifying patients requiring higher intensity anticoagulation.

Single-atom ligand changes affect breathing in an extended metal-organic framework.

2-Phenylpyridine-5,4'-dicarboxylic acid (1, dcppy), a derivative of 4,4'-biphenyldicarboxylic (2, bpdc) was used as the organic linking component for several metal-organic frameworks (MOFs). The pyridine component of 1 does not interfere with the solvothermal synthetic procedure, and hence both 1 and 2 form similar isoreticular MOFs. Zr(4+)-based UiO-67-dcppy, Al(3+)-based DUT-5-dcppy, Zn(2+)-based DMOF-1-dcppy, and interpenetrated Zn(2+)-based BMOF-1-dcppy were readily synthesized from 1. Similarly, isostructural frameworks from 2 were prepared (UiO-67, DUT-5, DMOF-1-bpdc, and interpenetrated BMOF-1-bpdc). The structures and physical properties of these frameworks were characterized by powder X-ray diffraction (PXRD), single X-ray diffraction (XRD), thermogravimetric analysis (TGA), and gas sorption analysis. Generally, frameworks prepared from 1 or 2 displayed similar properties; however, gas sorption data showed that BMOF-1-dcppy displayed a very large hysteresis with N(2) and CO(2) suggestive of possible framework flexibility. In contrast, the analogous framework prepared from 2 (BMOF-1-bpdc) showed low uptake of N(2) and CO(2). The substantial difference in the gas sorption behavior of these MOFs is attributed to the pyridine nature of 1 that results in weakened π-π interactions between the interpenetrated nets.