A mild deficiency of ADAMTS13 is associated with severity in COVID-19: comparison of the coagulation profile in critically and noncritically ill patients

Protein C and S activities in COVID-19: A systematic review and meta-analysis

COVID-19 has been associated with alterations in coagulation. Recent reports have shown that protein C and S activities are altered in COVID-19. This may affect the complications and outcome of the disease. However, their exact role in COVID-19 remains uncertain. The aim of the current study was therefore to analyze all papers in the literature on protein C and S activities in COVID-19. We searched three medical electronic databases. Of the 2442 papers, 28 studies were selected for the present meta-analysis. For the meta-analysis, means ± standard deviations with 95% confidence intervals (CI) for protein C and S activities were extracted. Pooled p values were calculated using STATA software. Protein C and S activities were significantly lower in COVID-19 patients than in healthy controls (pooled p values: 0.04 and 0.02, respectively). Similarly, protein C activities were considerably lower in nonsurviving patients (pooled p value = 0.00). There was no association between proteins C or S and thrombosis risk or ICU admission in COVID-19 patients (p value > 0.05). COVID-19 patients may exhibit lower activities of the C and S proteins, which might affect disease outcome; however, additional attention should be given when considering therapeutic strategies for these patients.

Numerical study of ultra-large von Willebrand factor multimers in coagulopathy

An excessive von Willebrand factor (VWF) secretion, coupled with a moderate to severe deficiency of ADAMTS13 activity, serves as a linking mechanism between inflammation to thrombosis. The former facilitates platelet adhesion to the vessel wall and the latter is required to cleave VWF multimers. As a result, the ultra-large VWF (UL-VWF) multimers released by Weibel-Palade bodies remain uncleaved. In this study, using a computational model based on first principles, we quantitatively show how the uncleaved UL-VWF multimers interact with the blood cells to initiate microthrombosis. We observed that platelets first adhere to unfolded and stretched uncleaved UL-VWF multimers anchored to the microvessel wall. By the end of this initial adhesion phase, the UL-VWF multimers and platelets make a mesh-like trap in which the red blood cells increasingly accumulate to initiate a gradually growing microthrombosis. Although high-shear rate and blood flow velocity are required to activate platelets and unfold the UL-VWFs, during the initial adhesion phase, the blood velocity drastically drops after thrombosis, and as a result, the wall shear stress is elevated near UL-VWF roots, and the pressure drops up to 6 times of the healthy condition. As the time passes, these trends progressively continue until the microthrombosis fully develops and the effective size of the microthrombosis and these flow quantities remain almost constant. Our findings quantitatively demonstrate the potential role of UL-VWF in coagulopathy.

Endotheliopathy in Acute COVID-19 and Long COVID

The pulmonary endothelium is a highly regulated organ that performs a wide range of functions under physiological and pathological conditions. Since endothelial dysfunction has been demonstrated to play a direct role in sepsis and acute respiratory distress syndrome, its role in COVID-19 has also been extensively investigated. Indeed, apart from the COVID-19-associated coagulopathy biomarkers, new biomarkers were recognised early during the pandemic, including markers of endothelial cell activation or injury. We systematically searched the literature up to 10 March 2023 for studies examining the association between acute and long COVID-19 severity and outcomes and endothelial biomarkers.

Biomarkers of endothelial dysfunction are associated with poor outcome in COVID-19 patients: A systematic review and meta-analysis

Numerous studies have linked coronavirus disease 2019 (COVID-19) with endothelial dysfunction and reported elevated levels of endothelial biomarkers in this disease. We conducted a systematic review and meta-analysis of the published evidence in this respect. A systematic literature search of PubMed and Scopus databases was performed to find studies investigating biomarkers of endothelial dysfunction in COVID-19 patients. Pooled standardized mean differences and their 95% confidence intervals were calculated for each biomarker using random effect model. 74 studies with 7668 patients were included. In comparison to patients with good outcome, those with poor outcome had higher levels of von Willebrand factor (vWF) (SMD: 0.83, 95% CI: 0.59-1.07, p < 0.00001), vWF:ADAMTS13 (1.23, (0.77-1.7), p < 0.00001), angiopoietin-2 (Ang-2) (1.06 (0.6-1.51), p < 0.0001), E-selectin (1.09 (0.55-1.63), p < 0.0001), P-selectin (0.59 (0.24-0.94), p = 0.001), syndecan-1 (0.99 (0.6-1.37), p < 0.00001), mid-regional pro-adrenomedullin (MR-proADM) (1.52 (1.35-1.68), p < 0.00001), vascular endothelial growth factor (0.27 (0.02-0.53), p = 0.03), soluble fms-like tyrosine kinase-1 (sFLT-1) (1.93 (0.65-3.21), p = 0.03) and lower levels of ADAMTS13 antigen (-0.69 (-0.9 to -0.47) p < 0.00001) and activity (-0.84 (-1.06 to -0.61) p < 0.0000). Plasminogen activator inhibitor-1 and tissue plasminogen activator levels were not different between the two groups (p < 0.05). There were elevated levels of endothelial dysfunction biomarkers in COVID-19 patients with poor outcome, indicating their possible role in disease severity and prognosis. In particular, MR-proADM, vWF, syndecan-1 and sFLT-1 showed a significant association with poor outcome in these patients.

Prognostic value of von Willebrand factor and ADAMTS13 in patients with COVID-19: A systematic review and meta-analysis

BACKGROUND

Endotheliopathy and coagulopathy appear to be the main causes for critical illness and death in patients with coronavirus disease 2019 (COVID-19). The adhesive ligand von Willebrand factor (VWF) has been involved in immunothrombosis responding to endothelial injury. Here, we reviewed the current literature and performed meta-analyses on the relationship between both VWF and its cleaving protease ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13) with the prognosis of COVID-19.

METHODS

We searched MEDLINE, Cochrane Library, Web of Science, and EMBASE databases from inception to 4 March 2022 for studies analyzing the relationship between VWF-related variables and composite clinical outcomes of patients with COVID-19. The VWF-related variables analyzed included VWF antigen (VWF:Ag), VWF ristocetin cofactor (VWF:Rco), ADAMTS13 activity (ADAMTS13:Ac), the ratio of VWF:Ag to ADAMTS13:Ac, and coagulation factor VIII (FVIII). The unfavorable outcomes were defined as mortality, intensive care unit (ICU) admission, and severe disease course. We used random or fixed effects models to create summary estimates of risk. Risk of bias was assessed based on the principle of the Newcastle-Ottawa Scale.

RESULTS

A total of 3764 patients from 40 studies were included. The estimated pooled means indicated increased plasma levels of VWF:Ag, VWF:Rco, and VWF:Ag/ADAMTS13:Ac ratio, and decreased plasma levels of ADAMTS13:Ac in COVID-19 patients with unfavorable outcomes when compared to those with favorable outcomes (composite outcomes or subgroup analyses of non-survivor versus survivor, ICU versus non-ICU, and severe versus non-severe). In addition, FVIII were higher in COVID-19 patients with unfavorable outcomes. Subgroup analyses indicated that FVIII was higher in patients admitting to ICU, while there was no significant difference between non-survivors and survivors.

CONCLUSIONS

The imbalance of the VWF-ADAMTS13 axis (massive quantitative and qualitative increases of VWF with relative deficiency of ADAMTS13) is associated with poor prognosis of patients with COVID-19.

Mikroangiopathien in der Schwangerschaft

Das Wissen um die Differentialdiagnose der Mikroangiopathien ist auch für Geburtshelfer:innen wichtig. So ist die Kombination aus einer Thrombopenie und Hämolysezeichen wegweisend in der Erkennung der Erkrankung. Es sollten die Differenzialdiagnosen bekannt sein, da diese zu unterschiedlichen Therapienotwendigkeiten führen und Langzeitschäden, beispielsweise für die Niere, vermieden werden müssen. Die Differenzialdiagnosen der Thrombopenie stellen den Einstieg für die weitere Diagnostik dar. In der Kombination mit Hämolysezeichen und Veränderungen der Erythrozytenmorphologie (Fragmentozyten) liegen unterschiedliche Ursachen für die Mikroangiopathie vor. Eine thrombotisch-thrombozytopenische Purpura (TTP) kann während der gesamten Schwangerschaft, aber insbesondere im letzten Trimenon, die Ursache für solche Veränderungen sein. Bei dieser finden sich häufig gastrointestinale oder auch zusätzliche neurologische Symptome. Die Präeklampsie, insbesondere beim HELLP(„hemolysis, elevated liver enzymes, and a low platelet count“)-Syndrom, kann ebenfalls zu einer Mikroangiopathie führen, dieses i.d.R. mit entsprechender Erhöhung des Blutdrucks und insbesondere mit einer deutlichen Erhöhung der Lebertransaminasen, ebenfalls typischerweise im letzten Trimenon kombiniert. Wenn entsprechende Veränderungen nach der Geburt auftreten und diese neben der Hämolyse mit einem Nierenversagen verbunden sind, kann es sich hierbei um ein atypisches hämolytisch-urämisches Syndrom (aHUS) handeln, das spezifisch durch Antikörper therapiert werden sollte. Neben der typischen Gerinnungsaktivierung im Sinne einer Thrombosierung findet sich bei COVID-19 („corona virus disease“) auch das gesamte Bild einer entsprechenden Mikroangiopathie, zum Teil durch entsprechende Aktivierung des Gerinnungssystem, zum Teil durch eine Verstärkung der anderen Mikroangiopathien. Für alle Bereiche werden die Differenzialdiagnosen und mögliche Therapien skizziert.

High levels of von Willebrand factor with reduced specific activities in hospitalized patients with or without COVID-19

The COVID-19 pandemic is often accompanied by severe respiratory illness and thrombotic complications. Von Willebrand Factor (VWF) levels are highly elevated in this condition. However, limited data are available on the qualitative activity of VWF in COVID-19. We measured plasma VWF levels quantitatively (VWF antigen) and qualitatively (ristocetin-induced platelet agglutination, glycoprotein IbM (GPIbM) binding, and collagen binding). Consistent with prior reports, VWF antigen levels were significantly elevated in hospitalized patients with or without COVID-19. The GPIbM and collagen binding activity-to-antigen ratios were significantly reduced, consistent with qualitative changes in VWF in COVID-19. Of note, critically ill hospitalized patients without COVID-19 had similar reductions in VWF activity-to-antigen ratios as patients with COVID-19. Our data suggest that qualitative changes in VWF in COVID-19 may not be specific to COVID-19. Future studies are warranted to determine the mechanisms responsible for qualitative changes in VWF in COVID-19 and other critical illnesses.• VWF levels were increased in COVID-19 compared to healthy controls.• VWF activity-to-antigen ratios were decreased in COVID-19 compared to healthy controls.• There were no differences in VWF activity-to-antigen ratios between hospitalized patients with or without COVID-19.• These findings are consistent with qualitative changes in VWF in systemic inflammation which are not specific to COVID-19.• Future studies are needed to define possible roles of changes in conformation or multimer length in the qualitative changes in VWF in systemic inflammation.

Distal arteriovenous fistula to preserve patency in COVID-19-associated acute limb ischemia

The purpose of this study was to report our institutional experience with patients with COVID-19 who developed acute limb ischemia during hospitalization and to determine the characteristics and clinical outcomes. Between March 2020 and January 2021, we treated 3 patients who were COVID-19-positive and developed acute limb ischemia after they received thromboprophylaxis. We performed an embolectomy by exposing the popliteal artery below the knee to treat an occlusion of the popliteal and tibial arteries. An infusion of unfractionated heparin was initiated immediately after surgery, maintaining a partial thromboplastin time ratio > 2.5 times the normal value and transferred the patients to the intensive care unit. However, after these patients developed recurrent acute limb ischemia in the same leg, we decided to perform an embolectomy of popliteal and tibial arteries at the ankle and created an arteriovenous fistula (AVF) with tibial veins using polypropylene 7-0. The first patient died from pneumonia after 3 weeks in the intensive care unit; at that time, the foot was viable with triphasic flow in the distal posterior tibial artery and the AVF was patent. The second and third patients are doing well, they can walk without any problems, and the tibial arteries and AFV were patent on duplex ultrasound after 6 months. The AVF allowed part of the flow of tibial arteries to divert into the small veins of the foot that have a low resistance to maintain patency of tibial vessels, despite a hypercoagulable state and extensive thrombotic microangiopathy in patients with COVID-19.