ICM focus on thrombosis and bleeding

Clinical guidance for unfractionated heparin dosing and monitoring in critically ill patients

INTRODUCTION

Unfractionated heparin is a widely used anticoagulant in critically ill patients. It has a well-established safety profile and remains an attractive option for clinicians due to its short half-life and reversibility. Heparin has a unique pharmacokinetic profile, which contributes to significant inter-patient and intra-patient variability in effect. The variability in anticoagulant effect combined with heparin's short half-life mean close monitoring is required for clinical efficacy and preventing adverse effects. To optimize heparin use in critically ill patients, effective monitoring assays and dose adjustment strategies are needed.

AREAS COVERED

This paper explores the use of heparin as an anticoagulant and optimal approaches to monitoring in critically ill patients.

EXPERT OPINION

Conventional monitoring assays for heparin dosing have significant limitations. Emerging data appear to favor using anti-Xa assay monitoring for heparin anticoagulation, which many centers have successfully adopted as the standard. The anti-Xa assay appears have important benefits relative to the aPTT for heparin monitoring in critically ill patients, and should be considered for broader use.

Mitochondrial disorder and treatment of ischemic cardiomyopathy: Potential and advantages of Chinese herbal medicine

Mitochondrial dysfunction is the main cause of damage to the pathological mechanism of ischemic cardiomyopathy. In addition, mitochondrial dysfunction can also affect the homeostasis of cardiomyocytes or endothelial cell dysfunction, leading to a vicious cycle of mitochondrial oxidative stress. And mitochondrial dysfunction is also an important pathological basis for ischemic cardiomyopathy and reperfusion injury after myocardial infarction or end-stage coronary heart disease. Therefore, mitochondria can be used as therapeutic targets against myocardial ischemia injury, and the regulation of mitochondrial morphology, function and structure is a key and important way of targeting mitochondrial quality control therapeutic mechanisms. Mitochondrial quality control includes mechanisms such as mitophagy, mitochondrial dynamics (mitochondrial fusion/fission), mitochondrial biosynthesis, and mitochondrial unfolded protein responses. Among them, the increase of mitochondrial fragmentation caused by mitochondrial pathological fission is the initial factor. The protective mitochondrial fusion can strengthen the interaction and synthesis of paired mitochondria and promote mitochondrial biosynthesis. In ischemia or hypoxia, pathological mitochondrial fission can promote the formation of mitochondrial fragments, fragmented mitochondria can lead to damaged mitochondrial DNA production, which can lead to mitochondrial biosynthesis dysfunction, insufficient mitochondrial ATP production, and mitochondrial ROS. Burst growth or loss of mitochondrial membrane potential. This eventually leads to the accumulation of damaged mitochondria. Then, under the leadership of mitophagy, damaged mitochondria can complete the mitochondrial degradation process through mitophagy, and transport the morphologically and structurally damaged mitochondria to lysosomes for degradation. But once the pathological mitochondrial fission increases, the damaged mitochondria increases, which may activate the pathway of cardiomyocyte death. Although laboratory studies have found that a variety of mitochondrial-targeted drugs can reduce myocardial ischemia and protect cardiomyocytes, there are still few drugs that have successfully passed clinical trials. In this review, we describe the role of MQS in ischemia/hypoxia-induced cardiomyocyte physiopathology and elucidate the relevant mechanisms of mitochondrial dysfunction in ischemic cardiomyopathy. In addition, we also further explained the advantages of natural products in improving mitochondrial dysfunction and protecting myocardial cells from the perspective of pharmacological mechanism, and explained its related mechanisms. Potential targeted therapies that can be used to improve MQS under ischemia/hypoxia are discussed, aiming to accelerate the development of cardioprotective drugs targeting mitochondrial dysfunction.

Modern thromboprophylaxis protocol based on guidelines applied in a respiratory intensive care unit: a single-center prospective cohort study

BACKGROUND

Critically ill patients in intensive care units (ICUs) are at high risk of venous thromboembolism (VTE). This study aimed to explore the prophylaxis effect under a guideline-based thromboprophylaxis protocol among critically ill patients in a respiratory ICU.

METHODS

For this single-center prospective cohort study, we followed the thromboprophylaxis protocol, which was drawn up based on relevant guidelines and Chinese experts' advice. Clinical data were entered into an electronic case report form and analyzed. Multivariate logistic regression was conducted to explore independent risk factors of VTE event under this protocol.

RESULTS

From August 1, 2014, to December 31, 2020, 884 patients underwent thromboprophylaxis according to this protocol; 10.5% of them received mechanical prophylaxis, 43.8% received pharmacological prophylaxis, and 45.7% received pharmacological combined with mechanical prophylaxis. The proportion of VTE events was 14.3% for patients who received the thromboprophylaxis protocol, of which 0.1% had pulmonary thromboembolism (PTE), 2.0% had proximal deep vein thrombosis (DVT), and 12.1% had isolated distal DVT. There was no significant difference between different thromboprophylaxis measures. Cirrhosis (OR 5.789, 95% CI [1.402, 23.894], P = 0.015), acute asthma exacerbation (OR 39.999, 95% CI [4.704, 340.083], P = 0.001), and extracorporeal membrane oxygenation treatment (OR 22.237, 95%CI [4.824, 102.502], P < 0.001) were independent risk factors for proximal DVT under thromboprophylaxis.

CONCLUSIONS

The thromboprophylaxis protocol based on guidelines applied in the ICU was practicable and could help decrease the proportion of PTE and proximal DVT events. The risk factors of VTE events happening under the thromboprophylaxis protocol require more attention.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02213978.

Incidence and Risk Factors for Cannula-Related Venous Thrombosis After Venovenous Extracorporeal Membrane Oxygenation in Adult Patients With Acute Respiratory Failure

OBJECTIVES

Venovenous extracorporeal membrane oxygenation is indicated in patients with severe refractory acute respiratory failure. Venous thrombosis due to indwelling catheters is a frequent complication. The aim of this study was to analyze the incidence of cannula-related thrombosis and its risk factors after venovenous extracorporeal membrane oxygenation.

DESIGN

Retrospective observational study.

SETTING

A medical ICU at the University Hospital Regensburg.

PATIENTS

We analyzed consecutive patients with severe respiratory failure (PaO2/FIO2 < 85 mm Hg and/or respiratory acidosis with pH < 7.25) who were successfully treated with venovenous extracorporeal membrane oxygenation in a medical ICU between 2010 and 2017.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

After extracorporeal membrane oxygenation weaning, duplex sonography or CT was conducted to detect cannula-related thrombosis. Thrombosis was classified as a large thrombosis by vein occlusion of greater than 50%. The incidence of thrombosis was correlated with risk factors such as coagulation variables (mean activated partial thromboplastin time ≤ 50 s, international normalized ratio antithrombin III, fibrinogen, plasma-free hemoglobin, platelets, and decline in D-dimer ≤ 50% the day after decannulation), cannula size, time on venovenous extracorporeal membrane oxygenation, renal failure, and underlying malignant disease. Data cut-off points were identified by receiver operating characteristic analysis. One-hundred seventy-two of 197 patients (87%) were screened. One-hundred six patients (62%) showed thrombosis that was considered large in 48 of 172 (28%). The incidence of thrombosis was higher in patients with a mean aPTT of less than or equal to 50 seconds (odds ratio, 1.02; p = 0.013) and in patients with a decline in D-dimer less than or equal to 50% (odds ratio, 2.76; p = 0.041) the day after decannulation following adjustment for risk factors.

CONCLUSIONS

The incidence of cannula-related venous thrombosis after venovenous extracorporeal membrane oxygenation is high. Reduced systemic anticoagulation may enhance the risk of thrombosis. Sustained elevation of D-dimer after decannulation may indicate thrombosis. Patients should undergo routine duplex sonography after extracorporeal membrane oxygenation to detect thrombosis formation in the cannulated vessel.