Can nebulised HepArin Reduce morTality and time to Extubation in Patients with COVID-19 Requiring invasive ventilation Meta-Trial (CHARTER-MT): Protocol and Statistical Analysis Plan for an investigator-initiated international meta-trial of prospective randomised clinical studies

Exploring the therapeutic role of early heparin administration in ARDS management: a MIMIC-IV database analysis

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a severe respiratory condition characterized by a high mortality rate, the management of which relies on supportive care and a profound understanding of its pathophysiology. Heparin, with its anticoagulant and potential anti-inflammatory properties, offers a new therapeutic opportunity for the treatment of ARDS.

METHODS

In this retrospective cohort study, we examined the MIMIC-IV database for ARDS patients who received prophylactic heparin within the first 72 h of ICU admission. Employing propensity score matching and inverse probability weighting (IPW) analysis, we evaluated the impact of early heparin use on patient outcomes, focusing on mortality rates.

RESULTS

Patients who received prophylactic heparin had a significantly lower in-hospital mortality rate compared to those who did not (13.55% vs 17.93%, HR = 0.71, 95% CI: 0.54-0.93, P = 0.012). This result remained significant after propensity score matching (12.75% vs 17.93%, HR = 0.65, 95% CI 0.47-0.90, P = 0.010). Analysis using five different statistical models indicated that early use of heparin significantly reduced the in-hospital mortality rate, with HR = 0.669 (95% CI 0.487-0.919, P = 0.013) in the doubly robust model without balanced covariates; HR = 0.705 (95% CI 0.515-0.965, P = 0.029) with all covariates considered; HR = 0.660 (95% CI 0.491-0.888, P = 0.006) in the propensity score (IPW) model; HR = 0.650 (95% CI 0.470-0.900, P = 0.010) in the propensity score matching model; and HR = 0.706 (95% CI 0.536-0.930, P = 0.013) in the multivariate Cox regression model. Secondary outcomes indicated that heparin use was also associated with reduced mortality rates at 60 days, and 90 days.

CONCLUSION

This research highlights that early prophylactic administration of heparin may substantially lower mortality in ARDS patients. These findings underscore the potential of heparin as a key component in the management of ARDS, offering a new perspective and novel strategies for clinical treatment.

Heparin, Low Molecular Weight Heparin, and Non-Anticoagulant Derivatives for the Treatment of Inflammatory Lung Disease

Unfractionated heparin has multiple pharmacological activities beyond anticoagulation. These anti-inflammatory, anti-microbial, and mucoactive activities are shared in part by low molecular weight and non-anticoagulant heparin derivatives. Anti-inflammatory activities include inhibition of chemokine activity and cytokine synthesis, inhibitory effects on the mechanisms of adhesion and diapedesis involved in neutrophil recruitment, inhibition of heparanase activity, inhibition of the proteases of the coagulation and complement cascades, inhibition of neutrophil elastase activity, neutralisation of toxic basic histones, and inhibition of HMGB1 activity. This review considers the potential for heparin and its derivatives to treat inflammatory lung disease, including COVID-19, ALI, ARDS, cystic fibrosis, asthma, and COPD via the inhaled route.

Nebulized Heparin to Reduce COVID-19-induced Acute Lung Injury: A Prospective Observational Study

Background

High mortality due to COVID-19 disease has been a serious concern, a few of the causes being disseminated intravascular coagulation (DIC) and venous thromboembolism. Considering this, some experts have used heparin. However, its role still needs to be validated.

Materials and methods

This study predicts the role of nebulized heparin in decreasing the severity of lung injury caused by COVID-19. Thirty patients admitted with COVID-19 acute respiratory distress syndrome (ARDS) in the intensive care unit (ICU) of All India Institute of Medical Sciences, Rishikesh, were included in this study, which was conducted over a period of 3 months. Patients were nebulized with 2 mL of heparin 5,000 units/mL IV formulation diluted with 3 mL of 0.9% sodium chloride, every 6 hours for a total duration of 7 days. Improvement in oxygenation (ratio of partial pressure of oxygen in blood and fraction of inspired oxygen delivered, pO₂/FiO₂ ratio) was calculated as the primary outcome. Other parameters like effect on inflammatory markers (neutrophil-lymphocyte ratio, total leukocyte count, interleukin (IL-6), and D-dimer values), time to liberate from mechanical ventilation, and hospital stay were calculated as secondary outcomes.

Results

In our study population, the mean age was 54.5 years and the majority of patients were males (79.0%). All patients received prone ventilation and none of them required tracheostomy. However, 5 patients (16.6%) succumbed to illness. After nebulization with unfractionated heparin, no statistically significant difference was seen in the neutrophil-lymphocyte ratio (mean = 6.87, p = 0.318) and interleukin (IL-6) levels (mean = 62.85, p = 0.6) over 7 days. Similarly, the D-dimer level also had no statistically significant change (mean = 1853.73 p = 0.570). However, there was a statistically significant improvement in oxygenation (pO₂/FiO₂ ratio) over 7 days (mean = 184.96, p = 0.00). Similarly, there was a significant improvement in PaO₂ (84.17 ± 33.82) and SO₂ (92.30 ± 3.49). Although, no significant changes were seen in the partial pressure of carbon dioxide on nebulized heparin administration.

Conclusion

Administration of nebulized heparin in COVID-19 pneumonia with mild ARDS may improve oxygenation and result in the improvement of inflammatory markers with variable sensitivity and specificity.

How to cite this article

Gupta B, Chandrakar S, Gupta N, Jain G. Nebulized Heparin to Reduce COVID-19-induced Acute Lung Injury: A Prospective Observational Study. Indian J Crit Care Med 2023;27(3): 222-224.

Heparin, Heparan Sulphate and Sepsis: Potential New Options for Treatment

Sepsis is a life-threatening hyperreaction to infection in which excessive inflammatory and immune responses cause damage to host tissues and organs. The glycosaminoglycan heparan sulphate (HS) is a major component of the cell surface glycocalyx. Cell surface HS modulates several of the mechanisms involved in sepsis such as pathogen interactions with the host cell and neutrophil recruitment and is a target for the pro-inflammatory enzyme heparanase. Heparin, a close structural relative of HS, is used in medicine as a powerful anticoagulant and antithrombotic. Many studies have shown that heparin can influence the course of sepsis-related processes as a result of its structural similarity to HS, including its strong negative charge. The anticoagulant activity of heparin, however, limits its potential in treatment of inflammatory conditions by introducing the risk of bleeding and other adverse side-effects. As the anticoagulant potency of heparin is largely determined by a single well-defined structural feature, it has been possible to develop heparin derivatives and mimetic compounds with reduced anticoagulant activity. Such heparin mimetics may have potential for use as therapeutic agents in the context of sepsis.

Pentosan polysulfate inhibits attachment and infection by SARS-CoV-2 in vitro: insights into structural requirements for binding

Two years since the outbreak of the novel coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic, there remain few clinically effective drugs to complement vaccines. One is the anticoagulant, heparin, which in 2004 was found able to inhibit invasion of SARS-CoV (CoV-1) and which has been employed during the current pandemic to prevent thromboembolic complications and moderate potentially damaging inflammation. Heparin has also been shown experimentally to inhibit SARS-CoV-2 attachment and infection in susceptible cells. At high therapeutic doses however, heparin increases the risk of bleeding and prolonged use can cause heparin-induced thrombocytopenia, a serious side effect. One alternative, with structural similarities to heparin, is the plant-derived, semi-synthetic polysaccharide, pentosan polysulfate (PPS). PPS is an established drug for the oral treatment of interstitial cystitis, is well-tolerated, and exhibits weaker anticoagulant effects than heparin. In an established Vero cell model, PPS and its fractions of varying molecular weights inhibited invasion by SARS-CoV-2. Intact PPS and its size-defined fractions were characterized by molecular weight distribution and chemical structure using nuclear magnetic resonance spectroscopy and liquid chromatography–mass spectrometry, then employed to explore the structural basis of interactions with SARS-CoV-2 spike protein receptor-binding domain (S1 RBD) and the inhibition of Vero cell invasion. PPS was as effective as unfractionated heparin, but more effective in inhibiting cell infection than low-molecular-weight heparin (on a weight/volume basis). Isothermal titration calorimetry and viral plaque-forming assays demonstrated size-dependent binding to S1 RBD and inhibition of Vero cell invasion, suggesting the potential application of PPS as a novel inhibitor of SARS-CoV-2 infection.