Endothelial Dysfunction in Resuscitated Cardiac Arrest (ENDO-RCA): safety and efficacy of low-dose prostacyclin administration and blood pressure target in addition to standard therapy, as compared to standard therapy alone, in post-cardiac arrest syndrome patients: study protocol for a randomized controlled trial

Dual Cardiac Arrests Leading to Hypercoagulability and Extensive Upper Extremity Deep Vein Thrombosis: A Hematological Case Report

Upper extremity (UE) deep vein thrombosis (DVT) is a rare yet significant complication that can occur following cardiac arrest (CA). CA initiates a prothrombotic state via various processes, including stasis, endothelial damage, and an impaired balance between thrombogenesis and fibrinolysis, which may contribute to UE DVT formation. Inadequate cardiopulmonary resuscitation (CPR) in the field may further exacerbate blood stasis and clot formation. This case report describes an 80-year-old male with a history of bladder cancer who experienced two cardiac arrest events and subsequently developed an extensive left UE DVT. Despite treatment with a heparin drip and other supportive measures, the patient's condition deteriorated, and he passed away on the tenth day of hospitalization. This case is the first to describe UE DVT post-CA. It underscores the importance of recognizing and proactively managing hypercoagulable states post-CA, which can lead to significant DVTs in atypical locations that may evolve into life-threatening conditions.

Endothelial BMP4 Promotes Leukocyte Rolling and Adhesion and Is Elevated in Patients After Survived Out-of-Hospital Cardiac Arrest

Leukocyte recruitment is a fundamental step in the inflammatory response during ischemia/reperfusion injury (IRI). Rolling and adhesion of leukocytes to activated endothelium promote tissue inflammation after IRI and require presentation of adhesion molecules E-selectin and ICAM-1 on the endothelial surface. Bone morphogenetic protein (BMP) 4 is a prominent member of the BMP family expressed and secreted by endothelial cells. BMP4 derived from endothelial cells has important functions in vascular disease but its influence on the leukocyte adhesion cascade during inflammation is incompletely understood. In the present study, we challenged mice with an inducible endothelial-specific BMP4 deletion (referred to as EC-BMP4^-/- mice) and their control littermates (EC-BMP4^+/+) with thioglycollate i.p. and assessed extravasation of different leukocyte subsets during peritonitis. Peritoneal lavages were performed and peritoneal cells were counted. Total cell count in lavages of EC-BMP4^-/- mice was markedly reduced compared with lavages of EC-BMP4^+/+ mice. FACS analyses of thioglycollate-elicited peritoneal cells revealed that diverse leukocyte subsets were reduced in EC-BMP4^-/- mice. Intravital microscopy of cremaster venules demonstrated that rolling and adhesion of leukocytes were significantly diminished in EC-BMP4^-/- mice in comparison with control mice in response to TNFα. These observations indicate that endothelial BMP4 is essential for rolling, adhesion, and extravasation of leukocytes in vivo. To understand the underlying mechanisms, levels of endothelial adhesion molecules E-selectin and ICAM-1 were quantified in EC-BMP4^-/- and EC-BMP4^+/+ mice by quantitative PCR and Western blotting. Interestingly, ICAM-1 and E-selectin expressions were reduced in the hearts of EC-BMP4^-/- mice. Next we confirmed pro-inflammatory properties of BMP4 in a gain of function experiments and found that administration of recombinant BMP4 in male C57BL/6 mice increased leukocyte rolling and adhesion in cremaster venules in vivo. To assess the regulation of BMP4 in inflammatory disease in humans, we collected plasma samples of patients from day 0 to day 7 after survived out-of-hospital cardiac arrest (OHCA, n = 42). Remarkably, plasma of OHCA patients contained significantly higher BMP4 protein levels compared with patients with coronary artery disease (CAD, n = 12) or healthy volunteers (n = 11). Subgroup analysis revealed that elevated plasma BMP4 levels after ROSC are associated with decreased survival and unfavorable neurological outcome. Collectively, endothelial BMP4 is a potent activator of inflammation in vivo that promotes rolling, adhesion, and extravasation of leukocyte subsets by induction of E-selectin and ICAM-1. Elevation of plasma BMP4 levels in the post-resuscitation period suggests that BMP4 contributes to pathophysiology and poor outcome of post-cardiac arrest syndrome.

A randomised double-blind pilot trial comparing a mean arterial pressure target of 65 mm Hg versus 72 mm Hg after out-of-hospital cardiac arrest

BACKGROUND

After resuscitation from out-of-hospital cardiac arrest, mean arterial pressure below 65 mm Hg is avoided with vasopressors. A higher blood-pressure target could potentially improve outcome. The aim of this pilot trial was to investigate the effect of a higher mean arterial pressure target on biomarkers of organ injury.

METHODS

This was a single-centre, double-blind trial of 50 consecutive, comatose out-of-hospital cardiac arrest patients randomly assigned in a 1:1 ratio to a mean arterial pressure target of 65 mm Hg (MAP65) or 72 mm Hg (MAP72). Modified blood pressure modules with a -10% offset were used, enabling a double-blind study design. End-points were biomarkers of organ injury including markers of endothelial integrity (soluble trombomodulin) brain damage (neuron-specific enolase) and renal function (estimated glomerular filtration rate).

RESULTS

Mean arterial pressure was significantly higher in MAP72 with a mean difference of 5 mm Hg (p_group=0.03). After 48 h, soluble trombomodulin (median (interquartile range)) was 8.2 (6.7-12.9) ng/ml and 8.3 (6.0-10.8) ng/ml (p=0.29), neuron-specific enolase was 20 (13-31 μg/l) and 18 (13-44 μg/l) p=0.79) and estimated glomerular filtration rate (mean (±standard deviation)) was 61±19 ml/min/1.73m2 and 48±22 ml/min/1.73 m2 (p=0.08) for the MAP72 and MAP65 groups, respectively. Renal replacement therapy was needed in eight patients (31%) in MAP65 and three patients (13%) in MAP72 (p=0.14).

CONCLUSIONS

Double-blind allocation to different mean arterial pressure targets is feasible in comatose out-of-hospital cardiac arrest patients. A mean arterial pressure target of 72 mm Hg compared to 65 mm Hg did not result in improved biomarkers of organ injury. We observed a trend towards preserved renal function in the MAP72 group.

Low dose Iloprost effect on platelet aggregation in comatose out-of-hospital cardiac arrest patients: A predefined sub-study of the ENDO-RCA randomized -phase 2- trial

PURPOSE

This is a predefined sub-study of the Endothelial Dysfunction in Resuscitated Cardiac Arrest (ENDO-RCA) trial. We aim to investigate Iloprost, a prostacyclin analogue, safety by evaluating change in whole blood platelet aggregometry (Multiplate) in out of hospital cardiac arrest (OHCA) patients from baseline to 96-h post randomization.

METHODS

A randomized, placebo controlled double-blinded trial in 46 OHCA patients. Patients were allocated 1:2 to 48 h Iloprost infusion, (1 ng/kg/min) or placebo (saline infusion). Platelet aggregation was determined by platelet aggregation tests ASPI-test (arachidonic acid); TRAP-test (thrombin-receptor activating peptide (TRAP)-6; RISTO test (Ristocetin); ADP test (adenosin diphosphat).

RESULTS

There was no significant difference between the iloprost and placebo groups according to ASPI, TRAP, RISTO and ADP platelet aggregation assays. Further, no significant differences regarding risk of bleeding were found between groups (Risk of bleeding: ASPI <40 U; TRAP <92 U; RISTO <35 U; ADP <50 U).

CONCLUSIONS

In conclusion, the iloprost infusion did not influence platelet aggregation as evaluated by the ASPI, TRAP, RISTO and ADP assays. There was no increased risk of bleeding or transfusion therapy. A decline in platelet aggregation was observed for the ASPI and ADP assays during the initial 96 h after OHCA.

TRIAL REGISTRATION

Trial registration at clinicaltrials.gov (identifier NCT02685618) on 18-02-2016.

"Endothelial Dysfunction in Resuscitated Cardiac Arrest (ENDO-RCA): Safety and efficacy of low-dose Iloprost, a prostacyclin analogue, in addition to standard therapy, as compared to standard therapy alone, in post-cardiac-arrest-syndrome patients."

OBJECTIVE

An increasingly recognized prognostic factor for out-of-hospital-cardiac-arrest (OHCA) patients is the ischemia-reperfusion injury after restored blood circulation. Endothelial injury is common in patients resuscitated from cardiac arrest and is associated with poor outcome. This study was designed to investigate if iloprost infusion, a prostacyclin analogue, reduces endothelial damage in OHCA patients.

METHODS

50 patients were randomized in a placebo controlled double-blinded trial and allocated 1:2 to 48-hours iloprost infusion, (1 ng/kg/min) or placebo (saline infusion). Endothelial biomarkers (soluble thrombomodulin (sTM), sE-selectin, syndecan-1, soluble vascular endothelial growth factor (sVEGF), vascular endothelial cadherine (VEcad), nucleosomes) and sympathoadrenal activation (epinephrine/norepinephrine) from baseline to 48 and 96-hours were evaluated.

RESULTS

Iloprost infusion did not influence endothelial biomarkers by the 48-hour endpoint. A rebound effect was observed with higher biomarker plasma values in the iloprost group (sTM p=0.02; Syndecan p=0.004; nucleosomes p<0.001; VEcad p<0.03) after 96-hours. There was a significant difference in 180-day mortality in favor of placebo. There was no difference regarding total adverse events between groups (p=0.73). Two patients were withdrawn in the iloprost group due to hypotension.

CONCLUSIONS

The administration of low-dose iloprost (1ng/kg/min) to OHCA patients did not significantly influence endothelial biomarkers as measured by the 48- hour endpoint. A rebound effect was however observed in the 96-hour statistical model, with increasing endothelial biomarker levels after cessation of the iloprost-infusion.

Cyclooxygenase inhibition prior to ventricular fibrillation induced ischemia reperfusion injury impairs survival and outcomes

Nonsteroidal anti-inflammatory medications (NSAIDs) are one of the most commonly used analgesics in the world. NSAIDs decrease prostaglandin synthesis through cyclooxygenase inhibition (COX-1 or COX-2). The effects of NSAIDs on survival and outcomes from global ischemia reperfusion events and specifically from cardiac arrest (CA) remain controversial. We hypothesized that NSAIDs prior to global whole-body ischemia reperfusion (I/R) injury impairs survival and outcomes. We explored this hypothesis in our swine model of Cardiac Arrest (CA) which involves global I/R with pretreatment using a predominantly COX-1 inhibitor (Indomethacin [COX-1/min COX-2 Inh], a COX-2 Inhibitor [COX-2-Inh, (Celecoxib)] or placebo control. We determined the effects of each inhibitor on a) survival, b) myocardial injury biomarker (Troponin 1), and c) Autonomic Nervous System (ANS) injury marker (heart rate variability [HRV]) up to 3 h after resuscitation. There were no survivals in COX-1/min COX-2-Inh pretreated animals and, 87% survived in both COX-2 Inhibited and control animals. COX-2 Inh pretreated animals had an 1800 fold increase of Troponin 1 compared to baseline whereas control animals had a 90 fold increase (p < 0.001). These results along with literature review of focal I/R in animal models with COX-2 overexpression, human studies of CA, and post myocardial infarction treatment with NSAIDs, support the hypothesis that NSAIDs prior to an I/R event impairs survival and outcomes. Specifically, predominantly COX-1 inhibition impairs survival, and COX-2 inhibition induces myocardial damage, autonomic nervous system dysfunction, and increases the risk for all-cause mortality and morbidity in humans post-MI which has significant implications for the nearly 10% of the population who are taking NSAIDs.

Validation and Clinical Evaluation of a Method for Double-Blinded Blood Pressure Target Investigation in Intensive Care Medicine

OBJECTIVES

No double-blinded clinical trials have investigated optimal mean arterial pressure targets in the ICU. The aim of this study was to develop and validate a method for blinded investigation of mean arterial pressure targets in patients monitored with arterial catheter in the ICU.

DESIGN

Prospective observational study (substudy A) and prospective, randomized, controlled clinical study (substudy B).

SETTING

ICU, Department of Cardiology, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark.

PATIENTS

Adult patients resuscitated from out-of-hospital cardiac arrest.

INTERVENTIONS

Standard blood pressure measuring modules were offset to display 10% lower or higher blood pressure values. We then: 1) confirmed this modification in vivo by comparing offset to standard modules in 22 patients admitted to the ICU. Thereafter we 2) verified the method in two randomized, clinical trials, each including 50 out-of-hospital cardiac arrest patients, where the offset of the blood pressure module was blinded to the treating staff.

MEASUREMENTS AND MAIN RESULTS

Substudy A showed that the expected separation of blood pressure measurements was achieved with an excellent correlation of the offset and standard modules (R = 0.997). Bland-Altman plots showed no bias of modified modules over a clinically relevant range of mean arterial pressure. The primary endpoint of the clinical trials was between-group difference of norepinephrine dose needed to achieve target mean arterial pressure. Trial 1 aimed at a 10% difference between groups in mean arterial pressure (targets: 65 and 72 mm Hg, respectively) and demonstrated a separation of 5 ± 1 mm Hg (p < 0.001). The difference in norepinephrine dose was not significantly different (0.03 ± 0.03 µg/kg/min; p = 0.42). Trial 2 aimed at a 20% difference between groups in mean arterial pressure (targets: 63 and 77 mm Hg, respectively). Separation was 12 ± 1 mm Hg (p < 0.01) in mean arterial pressure and 0.07 ± 0.03 µg/kg/min (p < 0.01) in norepinephrine dose.

CONCLUSIONS

The present method is feasible and robust and provides a platform for double-blinded comparison of mean arterial pressure targets in critically ill patients.