Recognition and diagnosis of acute type A aortic dissection in a large Belgian referral center – can we do better?

Background: Acute type A aortic dissection (ATAAD) has a poor prognosis unless promptly diagnosed and surgically treated. As ATAAD is relatively rare and clinical presentation may mimic other pathologies, diagnosis can be challenging. Objectives: The aim of this study is to evaluate the difficulties in diagnosing ATAAD. Methods: A monocentric, retrospective analysis was conducted of all patients undergoing surgical repair for acute type A aortic dissection in our hospital (a large Belgian referral center) between the 1st of January 2016 and the 31st of December 2020. Data were collected regarding patient’s demographics i.e. age and gender, time of first medical contact, referral from other hospitals, presenting symptoms, initial diagnosis, inappropriate antiplatelet or antithrombotic therapy, time to the correct diagnosis, time to initiate surgical repair, and one- year mortality. Results: Thirty-three patients were included. We found that a correct initial diagnosis was only made in twelve percent of patients with ATAAD. In twenty-one percent of patients, misdiagnoses led to inappropriate administration of antiplatelet or antithrombotic drugs pre-operatively. There was a difference in time from first medical contact to initiation of surgical repair between referred and non-referred patients. This time interval tended to be shorter in the latter group. Conclusions: The main finding of this analysis is the delayed diagnosis of ATAAD in the majority of patients. This trend is slightly higher in patients referred from other hospitals. To improve outcome in ATAAD, efforts should be made to increase awareness for the presenting symptoms, and appropriate diagnostic imaging should be performed in a timely manner.

Correction to: A randomized, open-label, adaptive, proof-of-concept clinical trial of modulation of host thromboinflammatory response in patients with COVID-19: the DAWn-Antico study

An amendment to this paper has been published and can be accessed via the original article.

A randomized, open-label, adaptive, proof-of-concept clinical trial of modulation of host thromboinflammatory response in patients with COVID-19: the DAWn-Antico study

BACKGROUND

The peak of the global COVID-19 pandemic has not yet been reached, and many countries face the prospect of a second wave of infections before effective vaccinations will be available. After an initial phase of viral replication, some patients develop a second illness phase in which the host thrombotic and inflammatory responses seem to drive complications. Severe COVID-19 disease is linked to high mortality, hyperinflammation, and a remarkably high incidence of thrombotic events. We hypothesize a crucial pathophysiological role for the contact pathway of coagulation and the kallikrein-bradykinin pathway. Therefore, drugs that modulate this excessive thromboinflammatory response should be investigated in severe COVID-19.

METHODS

In this adaptive, open-label multicenter randomized clinical trial, we compare low molecular weight heparins at 50 IU anti-Xa/kg twice daily-or 75 IU anti-Xa twice daily for intensive care (ICU) patients-in combination with aprotinin to standard thromboprophylaxis in hospitalized COVID-19 patients. In the case of hyperinflammation, the interleukin-1 receptor antagonist anakinra will be added on top of the drugs in the interventional arm. In a pilot phase, the effect of the intervention on thrombotic markers (D-dimer) will be assessed. In the full trial, the primary outcome is defined as the effect of the interventional drugs on clinical status as defined by the WHO ordinal scale for clinical improvement.

DISCUSSION

In this trial, we target the thromboinflammatory response at multiple levels. We intensify the dose of low molecular weight heparins to reduce thrombotic complications. Aprotinin is a potent kallikrein pathway inhibitor that reduces fibrinolysis, activation of the contact pathway of coagulation, and local inflammatory response. Additionally, aprotinin has shown in vitro inhibitory effects on SARS-CoV-2 cellular entry. Because the excessive thromboinflammatory response is one of the most adverse prognostic factors in COVID-19, we will add anakinra, a recombinant interleukin-1 receptor antagonist, to the regimen in case of severely increased inflammatory parameters. This way, we hope to modulate the systemic response to SARS-CoV-2 and avoid disease progressions with a potentially fatal outcome.

TRIAL REGISTRATION

The EU Clinical Trials Register 2020-001739-28 . Registered on April 10, 2020.

Endocrine and metabolic disturbances in critical illness: relation to mechanisms of organ dysfunction and adverse outcome

Critically ill patients face a high risk of death, which is mostly due to non-resolving multiple organ failure. The plethora of endocrine and metabolic disturbances that hallmark critical illness may play a key role. The major part of our research performed during the period 2004-2009 focused on the disturbed glucose metabolism that commonly develops during critical illness. The onset of this research interest was the landmark randomized clinical study on strict blood glucose control (80-110 mg/ dl) with intensive insulin therapy performed by Prof. Van den Berghe and our clinical team members. This study, published in 2001 in the New England Journal of Medicine, showed reduced morbidity and improved survival with intensive insulin therapy versus toleration of hyperglycemia up to 215 mg/dl. This review summarizes our findings in both patients and animal models on mechanisms contributing to the clinical benefits of strict blood glucose control. Intensive insulin therapy appeared to lower blood glucose levels by ameliorating insulin sensitivity and stimulation of glucose uptake in skeletal muscle, whereas hepatic insulin resistance was not affected. The therapy also improved the lipid profile and the immune response and attenuated inflammation. Maintenance of strict normoglycemia appeared essentially most important, rather than elevating insulin levels. Avoiding hyperglycemia protected the endothelium and the mitochondria. In our animal model, nutritional interventions counteracted the hypercatabolic state of critical illness and insulin improved myocardial contractility, but only when normoglycemia was maintained. Interestingly, we identified the adipose tissue as a functional storage depot for toxic metabolites during critical illness.

Tissue mRNA expression of the glucocorticoid receptor and its splice variants in fatal critical illness

BACKGROUND

Critical illness results in activation of the hypothalamic-pituitary-adrenal (HPA) axis, which might be accompanied by a peripheral adaptation in glucocorticoid sensitivity. Tissue sensitivity is determined by the active glucocorticoid receptor GRalpha, of which two splice variants involving the hormone-binding domain exist, GRbeta and GR-P.

OBJECTIVE

To study tissue mRNA expression of the GR and its splice variants in fatal critical illness.

DESIGN AND METHODS

We assessed mRNA expression of the GRalpha, GRbeta and GR-P variants in liver (n = 58) and muscle (n = 65) of patients who had died after intensive care, and had been randomized for insulin treatment. We analysed whether GR mRNA expression was associated with insulin treatment, cortisol levels and glucocorticoid treatment.

RESULTS

GRalpha and GR-P mRNA constituted 87 +/- 8% and 13 +/- 2%, respectively, of total GR mRNA in liver. GRbeta mRNA could only be amplified in five liver samples. All variants were present in most muscle samples (alpha = 96 +/- 11%, P = 3.9 +/- 0.4%, beta = 0.010 +/- 0.002%). GR expression was not associated with insulin therapy. A strong positive relationship was observed between the different GR variants in both liver and muscle (P < 0.001 for all). Serum cortisol levels were negatively associated with liver GRalpha and muscle GR-P expression (P < 0.05). mRNA expression of both liver GRalpha and GR-P, but not muscle GR, was substantially lower in patients who had received exogenous glucocorticoids (P < 0.01).

CONCLUSION

We demonstrate the presence of GRalpha and GR-P mRNA in liver and of GRalpha, GRbeta and GR-P mRNA in muscle, with no evidence for altered splicing in critical illness. In contrast to muscle GR, liver GR expression was substantially lower in patients receiving exogenous glucocorticoids.

Forskolin increases apical sodium conductance in cultured toad kidney cells (A6) by stimulating membrane insertion

The role of membrane traffic in the stimulation of apical Na+ permeability caused by increases in cytoplasmic cyclic AMP was assessed by measuring the effects of forskolin on transepithelial capacitance (CT), transepithelial conductance (GT), and short-circuit current (Isc) in A6 cultured toad kidney cells. Apical water permeability was probed by recording cell volume changes after reducing the osmolality of the apical bath. We found that forskolin does not increase the osmotic water permeability of the apical membrane of A6 cells, and thus does not stimulate the insertion of water channels. Comparison of the effects of forskolin and insulin on Na+ transport demonstrated that both agents produce reversible increases in CT, GT and Isc. GT and CT increased proportionally during the rising phase of the insulin response. However, a non-linear relationship between both parameters was recorded when forskolin was given in NaCl Ringer's solution. The relationship between CT and GT became linear after the effects of forskolin on Cl- conductances were eliminated by substituting Cl- by an impermeant anion. In contrast, in Cl--containing Na+-free solutions, the non-linearity became more pronounced. Successive additions of insulin and forskolin caused additive increases in CT. Because increases in CT and Na+ transport occurred in the absence of stimulation of water permeability and increases of CT and GT were directly proportional when Na+ was the major permeating ion across the apical membrane, we suggest that the increase in apical Na+ permeability in the presence of either forskolin or insulin is due to the insertion of channels residing in intracellular pools. In contrast, the increased Cl- permeability caused by forskolin may be related to the activation of channels already present in the membrane.

Cu2+ reveals different binding sites of amiloride and CDPC on the apical Na channel of frog skin

The effect of Cu2+ ions, present in the mucosal bathing solution, on the transepithelial short-circuit current (Isc) and conductance (Gt) and on the blocker-induced noise of apical Na channels, was studied on the isolated ventral skin of the frog Rana temporaria. Cu2+ effects were concentration-dependent, the full effect being reached at 50 micromol/l. Cu2+ increased Isc and Gt; this effect was eliminated by high concentrations of amiloride (30 micromol/l) and of CDPC (150 micromol/l). Cu2+ markedly reduced the corner frequency (fc) of the Na channel noise, while having virtually no effect on the fc of CDPC-induced noise. Cu2+ reduces the association rate constant of amiloride to the Na channel to one third; this effect is interpreted as indicating competition between Cu2+ and amiloride for the same (negatively charged) binding site on the channel, while CDPC appears to bind on a different site.