Targeted metabolomics in Out-of-Hospital Cardiac arrest (OHCA)

Background

Out-of-hospital cardiac arrest is a leading cause of death. Even if successfully resuscitated, mortality and morbidity remain high due to ischemic and reperfusion injury (I/R). The oxygen deprivation leads to a metabolic derangement amplified upon reperfusion resulting in an uncontrolled generation of reactive oxygen species, triggering cell death mechanisms and organ damage. Understanding the I/R damage in humans following OHCA remains sparse, with no existing treatment to attenuate the reperfusion injury.

Aim

Describe metabolic derangement in patients following OHCA.

Methods

Blood samples from consecutive resuscitated unconscious OHCA patients drawn at hospital admission were analyzed using ultra-performance liquid mass-spectrometry. Sixty-one metabolites of the ∼3000 compounds detected were prespecified for quantification and analyzed in the current study. We used hierarchical cluster data analysis to identify metabolic clusters/phenotypes.

Results

In total, 163 patients were included, of which 143 (88%) were men, and the median age was 62 years (53–68). All measured metabolites from the tricarboxylic (TCA) cycle were significantly higher in non-survivors vs. survivors (180-days survival). Hierarchical clustering identified four (A-D) phenotypes of patients with distinct metabolic profiles. The mortality was significantly different in two phenotypes; A and B (A: 62% and B: 59% vs. C: 21% and D: 24%, p<0.001). There were no significant differences in age between the four phenotypes (p=0.35). Phenotype A and B had longer time to ROSC (A: 33 min (21–43), B: 27 min (24–35), C: 18 min (13–28), and D: 18 min (12–25), p<0.001). Phenotype A and D, who both had higher levels of free fatty acids, also a higher prevalence of ST-elevation or acute left bundle branch block in first ECG as compared to phenotype B and C (A: 76%, B: 55%, C: 36% and D: 75%, p<0.001.

Conclusion

Circulating levels of metabolites from the TCA cycle best described the variance between survivors and non-survivors. Four different metabolic phenotypes were identified. These phenotypes had significantly different mortality.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Novo Nordisk Foundation

An explorative metabolomic analysis of the endothelium in pulmonary hypertension

Pulmonary hypertension (PH) is classified into five clinical diagnostic groups, including group 1 [idiopathic pulmonary arterial hypertension (IPAH) and connective tissue disease-associated PAH (CTD-aPAH)] and group 4 (chronic thromboembolic pulmonary hypertension (CTEPH)). PH is a progressive, life-threatening, incurable disease. The pathological mechanisms underlying PH remain elusive; recent evidence has revealed that abnormal metabolic activities in the endothelium may play a crucial role. This research introduces a novel approach for studying PH endothelial function, building on the genome-scale metabolic reconstruction of the endothelial cell (EC) to investigate intracellular metabolism. We demonstrate that the intracellular metabolic activities of ECs in PH patients cluster into four phenotypes independent of the PH diagnosis. Notably, the disease severity differs significantly between the metabolic phenotypes, suggesting their clinical relevance. The significant metabolic differences between the PH phenotypes indicate that they may require different therapeutic interventions. In addition, diagnostic capabilities enabling their identification is warranted to investigate whether this opens a novel avenue of precision medicine.

Viscoelastic haemostatic assay augmented protocols for major trauma haemorrhage (ITACTIC): a randomized, controlled trial

PURPOSE

Contemporary trauma resuscitation prioritizes control of bleeding and uses major haemorrhage protocols (MHPs) to prevent and treat coagulopathy. We aimed to determine whether augmenting MHPs with Viscoelastic Haemostatic Assays (VHA) would improve outcomes compared to Conventional Coagulation Tests (CCTs).

METHODS

This was a multi-centre, randomized controlled trial comparing outcomes in trauma patients who received empiric MHPs, augmented by either VHA or CCT-guided interventions. Primary outcome was the proportion of subjects who, at 24 h after injury, were alive and free of massive transfusion (10 or more red cell transfusions). Secondary outcomes included 28-day mortality. Pre-specified subgroups included patients with severe traumatic brain injury (TBI).

RESULTS

Of 396 patients in the intention to treat analysis, 201 were allocated to VHA and 195 to CCT-guided therapy. At 24 h, there was no difference in the proportion of patients who were alive and free of massive transfusion (VHA: 67%, CCT: 64%, OR 1.15, 95% CI 0.76-1.73). 28-day mortality was not different overall (VHA: 25%, CCT: 28%, OR 0.84, 95% CI 0.54-1.31), nor were there differences in other secondary outcomes or serious adverse events. In pre-specified subgroups, there were no differences in primary outcomes. In the pre-specified subgroup of 74 patients with TBI, 64% were alive and free of massive transfusion at 24 h compared to 46% in the CCT arm (OR 2.12, 95% CI 0.84-5.34).

CONCLUSION

There was no difference in overall outcomes between VHA- and CCT-augmented-major haemorrhage protocols.