The vulnerable endothelium: priming the vascular endothelium for thrombosis with unfractionated heparin: biologic plausibility for observations from the Superior Yield of the New Strategy of Enoxaparin, Revascularization and GlYcoprotein IIb/IIIa Inhibitors (SYNERGY) trial

Preliminary study of hypoxia-related cardiovascular mediator-markers in patients with end-stage renal disease with and without diabetes and the effects of haemodialysis

BACKGROUND

Evidence points to activation of pro-inflammatory and pro-thrombotic stimuli during the haemodialysis process in end-stage renal disease (ESRD) with potential to predispose to cardiovascular events. Diabetes is associated with a higher incidence of cardiovascular disease in haemodialysis patients. We tested the hypothesis that a range of mediators and markers that modulate cardiovascular risk are elevated in haemodialysis patients with diabetes compared to those without.

METHODS

Men and women with diabetes (n = 6) and without diabetes (n = 6) aged 18-90 years receiving haemodialysis were recruited. Blood samples were collected and analysed pre- and post-haemodialysis sessions for (platelet-monocyte conjugates (PMC), oxidised LDL (Ox-LDL), endothelin 1 (ET-1) and vascular endothelial growth factor (VEGF-A).

RESULTS

PMC levels significantly increased after haemodialysis in both groups (diabetes p = 0.047; non-diabetes p = 0.005). Baseline VEGF-A was significantly higher in people with diabetes (p = 0.009) and post-dialysis levels were significantly reduced in both groups (P = 0.002). Ox-LDL and CRP concentrations were not significantly different between groups nor affected in either group post-dialysis. Similarly, ET-1 concentrations were comparable in all patients at baseline, with no change post-dialysis in either group.

CONCLUSIONS

In this pilot study, we have confirmed that circulating PMCs are increased following dialysis irrespective of diabetes status. This is likely to be a mechanistic process and offers a potential explanation for high rates of vascular events associated with haemodialysis. The higher VEGF-A concentrations between patients with and without diabetes is a previously unreported finding in diabetic ESRD. Further research is merited to establish whether VEGF-A is a marker or mediator (or both) of cardiovascular risk in haemodialysis.

Sympathoadrenal activation and endothelial damage are inter correlated and predict increased mortality in patients resuscitated after out-of-hospital cardiac arrest. a post Hoc sub-study of patients from the TTM-trial

Objective

Sympathoadrenal activation and endothelial damage are hallmarks of acute critical illness. This study investigated their association and predictive value in patients resuscitated from out-of-hospital cardiac arrest (OHCA).

Methods

Post-hoc analysis of patients included at a single site in The Targeted Temperature Management at 33 degrees versus 36 degrees after Cardiac Arrest (TTM) trial. The main study reported similar outcomes with targeting 33 versus 36 degrees. TTM main study ClinicalTrials.gov: NCT01020916. One hundred sixty three patients resuscitated from OHCA were included at a single site ICU. Blood was sampled a median 135 min (Inter Quartile Range (IQR) 103-169) after OHCA. Plasma catecholamines (adrenaline, noradrenaline) and serum endothelial biomarkers (syndecan-1, thrombomodulin, sE-selectin, sVE-cadherin) were measured at admission (immediately after randomization). We had access to data on demography, medical history, characteristics of the OHCA, patients and 180-day outcome.

Results

Adrenaline and noradrenaline correlated positively with syndecan-1 and thrombomodulin i.e., biomarkers reflecting endothelial damage (both p<0.05). Overall 180-day mortality was 35%. By Cox analyses, plasma adrenaline, serum sE-selectin, reflecting endothelial cell activation, and thrombomodulin levels predicted mortality. However, thrombomodulin was the only biomarker independently associated with mortality after adjusting for gender, age, rhythm (shockable vs. non-shockable), OHCA to return of spontaneous circulation (ROSC) time, shock at admission and ST elevation myocardial infarction (30-day Hazards Ratio 1.71 (IQR 1.05-2.77), p=0.031 and 180-day Hazards Ratio 1.65 (IQR 1.03-2.65), p=0.037 for 2-fold higher thrombomodulin levels).

Conclusions

Circulating catecholamines and endothelial damage were intercorrelated and predicted increased mortality. Interventions aiming at protecting and/or restoring the endothelium may be beneficial in OHCA patients.