Asynchronous training for ultrasound-guided peripheral IV placement among critical care nurses

OBJECTIVE

Teaching ultrasound (US) guidance for placement of peripheral intravenous (PIV) catheters requires significant time for synchronous didactic and hands-on training. The investigators assessed the feasibility of an asynchronous model for critical care nurses to learn the novel skill of US-guided PIV placement. Secondary outcomes included the percentage of successful attempts and number of sticks per attempt for anatomy versus US-guided approaches.

METHODS

The investigators built a self-contained training cart for learners to practice and record their performance. Training occurred asynchronously. The learners recorded data from PIV attempts. Participants completed pre- and post-training surveys. Data from this prospective observational cohort was analyzed for descriptive and comparative statistics, using Kirkpatrick's Model for evaluation of this educational intervention.

RESULTS

During a 6 month period, 21 nurses completed the asynchronous training, with eight recording their PIV placements. 81.0% of the training occurred outside of a Monday to Friday 9AM-5PM period. There were 64 attempts by anatomy approach and 84 with US-guidance. The anatomic approach was successful in 35.9% of attempts with a mean of 1.5 sticks (SD 1.0, Range 1-5). The US-guided approach had a statistically significant greater rate of success (77.4%; p < 0.001) with a mean of 1.2 sticks (SD 1.2, range 1-2, p < 0.01). Participants reported increased confidence in US-guided PIV placement and enjoyment with this method of learning.

CONCLUSIONS

Asynchronous learning model with cart-based instruction and practice is a feasible means for nurses to learn US-guided PIV placement. Significant outcomes were seen across Kirkpatrick levels I-IV for educational outcome assessment.

Nirmatrelvir/Ritonavir Use and Hospitalizations or Death in a Previously Uninfected Nonhospitalized High-Risk Population With COVID-19: A Matched Cohort Study

OBJECTIVE

To determine the association of nirmatrelvir/ritonavir (NMV/r) with hospitalization or death within 30 days as compared with untreated controls previously uninfected and nonhospitalized.

METHODS

We used a matched cohort design using inverse probability of treatment weight (IPTW). Individuals prescribed NMV/r within 3 days of COVID-19 diagnosis were compared with IPTW-based untreated controls. Variables for IPTW included age, race, sex, body mass index, geographic location, vaccination status, and multiple comorbidities. Additional analyses were conducted on NMV/r-treated and propensity score-matched untreated controls.

RESULTS

Among 7615 individuals prescribed NMV/r and 62 077 controls identified between 1 January 2022 and 25 February 2023, the risk of hospitalization/death was lower among NMV/r-treated persons vs untreated controls (243 vs 3468 events; absolute risk difference [ARD], -2.36 [95% CI, -2.57 to -2.14]). The difference was significant for those >60 and ≤60 years old (ARD, -3.86 [95% CI, -4.19 to -3.54] vs -0.27 [95% CI, -0.51 to -0.03]) and for persons asymptomatic and symptomatic (ARD, -7.09 [95% CI, -7.62 to -6.55] vs -1.46 [95% CI, -1.66 to -1.25]). Significant benefit was observed among individuals unvaccinated and vaccinated, with or without a booster dose.

CONCLUSIONS

NMV/r is associated with a significant reduction in 30-day hospitalization or death among individuals previously uninfected and nonhospitalized.

Molnupiravir Use and 30-Day Hospitalizations or Death in a Previously Uninfected Nonhospitalized High-risk Population With COVID-19

BACKGROUND

Clinical benefit of molnupiravir (MPV) in coronavirus disease 2019 (COVID-19)-infected subpopulations is unclear.

METHODS

We used a matched cohort study design to determine the rate of hospitalization or death within 30 days of COVID-19 diagnosis among MPV treated and untreated controls. Participants were nonhospitalized, previously uninfected Veterans with a first confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection between 1 January and 31 August 2022, who were prescribed MPV within 3 days of COVID-19 diagnosis, and matched individuals who were not prescribed MPV.

RESULTS

Among 1459 matched pairs, the incidence of hospitalization/death was not different among MPV treated versus untreated controls (48 vs 44 cases; absolute risk difference [ARD], 0.27; 95% confidence interval [CI], -.94 to 1.49). No benefit was observed among those >60 or ≤60 years old (ARD, 0.27; 95% CI, -1.25 to 1.79 vs ARD, -0.29; 95% CI, -1.22 to 1.80), those with specific comorbidities, or by vaccination status. A significant benefit was observed in asymptomatic but not in symptomatic persons (ARD, -2.80; 95% CI, -4.74 to -.87 vs ARD, 1.12; 95% CI -.31 to 2.55). Kaplan-Meier curves did not show a difference in proportion of persons who were hospitalized or died among MPV treated compared with untreated controls (logrank P = .7).

CONCLUSIONS

MPV was not associated with a reduction in hospitalization or death within 30 days of COVID-19 diagnosis. A subgroup of patients presenting without symptoms experienced a benefit.

Relative Vaccine Effectiveness of a Severe Acute Respiratory Syndrome Coronavirus 2 Messenger RNA Vaccine Booster Dose Against the Omicron Variant

BACKGROUND

The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may be less effective against the Omicron variant than against earlier variants. With recent resurgence of SARS-CoV-2 cases, the role of booster doses of the vaccine needs to be highlighted.

METHODS

Using a retrospective cohort study design emulating a target trial, we determined the relative vaccine effectiveness (RVE) of a homologous booster dose of a SARS-CoV-2 messenger RNA (mRNA) vaccine compared with the primary vaccine series alone in preventing infection, hospitalization, and intensive care unit admission, and death in the Department of Veterans Affairs healthcare system in the United States. Among infection-free survivors who received 2 doses of a mRNA vaccine before 30 April 2021, we identified those who received a booster between 22 September and 25 December 2021 and matched them 1:1 with individuals who did not receive a booster.

RESULTS

Among 2 384 272 previously uninfected persons with 2 doses of an mRNA vaccine by 30 April 2021, we identified 462 950 booster recipients between 22 September and 25 December 2021, who were matched 1:1 with non-booster recipients. The RVE (95% confidence interval) was 19% (17%-22%) for confirmed infection, 52% (46%-57%) for hospitalization, and 83% (65%-92%) for intensive care unit admission or death. Recipients of the mRNA-1273 vaccine had a lower cumulative incidence of infections and hospitalizations than recipients of the BNT162b2 vaccine (log-rank P <.001 for both comparisons).

CONCLUSIONS

While the RVE of SARS-CoV-2 mRNA booster vaccine dose in preventing infection against the Omicron variant is low, it is substantial in preventing hospitalization and high in preventing the most severe/critical disease.

Could treatment with immunomodulatory agents targeting IL-1, IL-6, or JAK signalling improve outcomes in patients with severe influenza pneumonia? A systematic and narrative review

Background: Influenza is a global cause of morbidity and mortality and a significant risk for a future pandemic infection. Host hyperinflammation, similar to that seen in COVID-19, may occur in response to influenza virus pneumonia, with Janus kinase (JAK) signalling and proinflammatory cytokines Interleukin (IL)-1 and IL-6 involved. Immune modulation treatment of hospitalised and critically ill COVID-19 patients, including with IL-6 and JAK inhibitors, has been found to be beneficial. Significant interest exists in the use of immunomodulatory agents targeting these pathways in the treatment of severe influenza pneumonia. Methods: We conducted a review with both systematic and narrative methods to assess whether, in patients with severe influenza pneumonia, treatment with immunomodulatory agents targeting IL-1, IL-6 or JAK signalling, in comparison to no immune modulation, is beneficial and improves clinical outcomes. Results: Our systematic search screened 5409 records and found no randomised controlled trials of IL-1, IL-6 or JAK immunomodulatory agents in patients with severe influenza pneumonia. To support this systematic search, we provide a narrative review of the biological rationale, previous use of these agents, including in hospitalised patients with COVID-19, and an overview of their safety profiles. Conclusions: Although immune modulation has proven successful in treating hospitalised and critically ill patients with COVID-19 and a biological rationale exists for testing these agents in influenza, no agents targeting IL-1, IL-6 or JAK signalling have been assessed in randomised controlled trials of patients with severe influenza pneumonia. This highlights a significant evidence gap.

Variation in Clinical Treatment and Outcomes by Race Among US Veterans Hospitalized With COVID-19

IMPORTANCE

Patients from racially and ethnically minoritized populations, such as Black and Hispanic patients, may be less likely to receive evidence-based COVID-19 treatments than White patients, contributing to adverse clinical outcomes.

OBJECTIVE

To determine whether clinical treatments and outcomes among patients hospitalized with COVID-19 were associated with race.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was conducted in 130 Department of Veterans Affairs Medical Centers (VAMCs) between March 1, 2020, and February 28, 2022, with a 60-day follow-up period until May 1, 2022. Participants included veterans hospitalized with COVID-19. Data were analyzed from May 6 to June 2, 2022.

EXPOSURES

Self-reported race.

MAIN OUTCOMES AND MEASURES

Clinical care processes (eg, intensive care unit [ICU] admission; organ support measures, including invasive and noninvasive mechanical ventilation; prone position therapy, and COVID-19-specific medical treatments) were quantified. Clinical outcomes of interest included in-hospital mortality, 60-day mortality, and 30-day readmissions. Outcomes were assessed with multivariable random effects logistic regression models to estimate the association of race with outcomes not attributable to known mediators, such as socioeconomic status and age, while adjusting for potential confounding between outcomes and mediators.

RESULTS

A total of 43 222 veterans (12 135 Black veterans [28.1%]; 31 087 White veterans [71.9%]; 40 717 [94.2%] men) with a median (IQR) age of 71 (62-77) years who were hospitalized with SARS-CoV-2 infection were included. Controlling for site of treatment, Black patients were equally likely to be admitted to the ICU (4806 Black patients [39.6%] vs 13 427 White patients [43.2%]; within-center adjusted odds ratio [aOR], 0.95; 95% CI, 0.88-1.02; P = .17). Two-thirds of patients treated with supplemental oxygen or noninvasive or invasive mechanical ventilation also received systemic steroids, but Black veterans were less likely to receive steroids (within-center aOR, 0.88; 95% CI, 0.80-0.96; P = .004; between-center aOR, 0.67; 95% CI, 0.48-0.96; P = .03). Similarly, Black patients were less likely to receive remdesivir (within-center aOR, 0.89; 95% CI, 0.83-0.95; P < .001; between-center aOR, 0.68; 95% CI, 0.47-0.99; P = .02) or treatment with immunomodulatory drugs (within-center aOR, 0.77; 95% CI, 0.67-0.87; P < .001). After adjusting for patient demographic characteristics, chronic health conditions, severity of acute illness, and receipt of COVID-19-specific treatments, there was no association of Black race with hospital mortality (within-center aOR, 0.98; 95% CI, 0.86-1.10; P = .71) or 30-day readmission (within-center aOR, 0.95; 95% CI, 0.88-1.04; P = .28).

CONCLUSIONS AND RELEVANCE

These findings suggest that Black veterans hospitalized with COVID-19 were less likely to be treated with evidence-based COVID-19 treatments, including systemic steroids, remdesivir, and immunomodulatory drugs.

Rate and Risk Factors for Severe/Critical Disease Among Fully Vaccinated Persons With Breakthrough Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection in a High-Risk National Population

BACKGROUND

Breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections after vaccination have been reported. Outcomes among persons with breakthrough infection are poorly understood.

METHODS

We identified all veterans with a confirmed SARS-CoV-2 infection >14 days after the second dose of an mRNA vaccine between 15 December 2020 and 30 June 2021 and propensity score-matched unvaccinated controls with SARS-CoV-2 infection. The primary outcome was severe/critical disease, defined as admission to an intensive care unit, need for mechanical ventilation, or death within 28 days of diagnosis or during index hospitalization.

RESULTS

Among 502 780 vaccinated and 599 974 unvaccinated persons, there were 2332 (0.5%) breakthrough infections in the vaccinated group and 40 540 (6.8%) infections in the unvaccinated group over a follow-up period of 69 083 person-days in each group. Among these groups, we identified 1728 vaccinated persons with breakthrough infection (cases) and 1728 propensity score-matched unvaccinated controls with infection. Among the former, 95 (5.5%) persons met the criteria for severe/critical disease, while 200 (11.6%) persons met the criteria among the latter group. The incidence rate for severe/critical disease per 1000 person-days (95% confidence interval [CI]) was .55 (.45-.68) among vaccinated persons with breakthrough infection and 1.22 (1.07-1.41) among the unvaccinated matched controls who developed infection (P < .0001). Risk was higher; the hazard ratio (95% CI) with increasing age per 10-year increase was 1.25 (1.11-1.41); for those with >4 comorbidities, it was 2.85 (1.49-5.43), while being vaccinated was associated with strong protection against severe/critical disease (HR, 0.41; 95% CI: .32-.52).

CONCLUSIONS

The rate of severe/critical disease is higher among older persons and those with >4 comorbidities but lower among fully vaccinated persons with breakthrough infection compared with unvaccinated controls who develop infection.

Vaccine Effectiveness of 3 Versus 2 Doses of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA Vaccines in a High-Risk National Population

BACKGROUND

Knowledge of the vaccine effectiveness (VE) of a third or booster vaccine dose in preventing SARS-CoV-2 infection or its consequences is critical in developing recommendations for their use. We determined relative VE of 3 vs 2 doses of an mRNA vaccine in preventing symptomatic SARS-CoV-2 infection, hospitalization, and severe/critical disease.

METHODS

Among veterans who had received 2 doses of an mRNA vaccine by 30 April 2021, we identified those who received a third dose of the same vaccine between 22 September and 24 November 2021 and 1:1 matched controls who had not received their third dose by then. Using Cox proportional hazards model, we calculated adjusted hazards ratios for symptomatic infection, hospitalization, and intensive care unit (ICU) admission or death after SARS-CoV-2-positive test.

RESULTS

Among 2 321 366 veterans who received 2 doses of Pfizer BNT-162b2 or Moderna mRNA-1273 vaccine by 30 April 2021, we matched 395 686 persons who received a third dose of the same vaccine between 22 September and 24 November 2021 to controls who did not receive a third dose. Adjusted HRs (95% CI) were .15 (.11-.21) for symptomatic infection and .18 (.13-.26) for hospitalizations for 3 vs 2 doses, corresponding to relative VE of 85% and 82%. Five ICU admissions or deaths were observed (4 among recipients of 2 doses). There was no difference in VE between BNT162b2 versus mRNA-1273 recipients.

CONCLUSIONS

A third dose of a SARS-CoV-2 mRNA vaccine is associated with high VE against symptomatic infection, hospitalization, and critical disease in the pre-Omicron era.

Real-World Effectiveness of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) mRNA Vaccines in Preventing Confirmed Infection in Patients on Chronic Hemodialysis

BACKGROUND

Persons on chronic hemodialysis have a significantly diminished humoral immune response to SARS-CoV-2 vaccines. Whether this translates to reduced vaccine effectiveness (VE) is unknown.

METHODS

We used the US Department of Veterans Affairs COVID-19 Shared Data Resource to identify all veterans who were tested for SARS-CoV-2 between 26 January and 31 August 2021. Using International Classification of Diseases, 10th edition, codes and attendance at a dialysis clinic/center, we identified those who were on chronic hemodialysis. We used a test-negative, case-control design using a doubly robust logistic regression model to determine the VE of the BNT-162b2 (Pfizer) or mRNA-1273 (Moderna) vaccines in preventing confirmed SARS-CoV-2 infection.

RESULTS

Among 847 199 veterans tested for SARS-CoV-2 between 26 January and 31 August 2021, there were 6076 veterans on chronic hemodialysis. Among those, we identified 1270 cases (580 fully vaccinated) and 2959 controls (2120 fully vaccinated). The overall VE >14 days after the second dose in preventing documented infection was 68.2% (95% CI: 62.6-72.9%). VE was 68.9% (95% CI: 61.9-74.7%) for Pfizer BNT-162b2 and 66.7% (95% CI: 58.9-73.0%) for Moderna mRNA-1273 vaccine. There was no difference in VE by age (<70 vs >70 years), race, or sex. There were no events recorded in persons with a Charlson's comorbidity index score <2.

CONCLUSIONS

VE of 2 doses of current mRNA vaccines in preventing SARS-CoV-2 infection in persons on chronic hemodialysis is lower than historic VE rates in the general population. Effects of additional doses in improving VE in this special population need further study.

Comparative COVID-19 Vaccine Effectiveness Over Time in Veterans

Background

Comparative effectiveness of coronavirus disease 2019 (COVID-19) vaccines across patient subgroups is poorly understood and essential to precisely targeting vaccination strategies.

Methods

We used the US Department of Veterans Affairs COVID-19 Shared Data Resource to identify veterans who utilize VA health care and had no documented severe acute respiratory syndrome coronavirus 2 infection before December 11, 2020. Using a test-negative case-control design (TND), we used conditional logistic regression with adjustment for covariates to estimate vaccine effectiveness (VE) over time for veterans who received 2 doses of mRNA vaccines or 1 dose of Ad26.Cov2.S.

Results

We identified 4.8 million veterans with a mean age of 64 years, of whom 58% had ≥1 chronic disease. Vaccine effectiveness for symptomatic infections, hospitalizations, and ICU admission or death declined over time and varied by the type of vaccine (P < 0.01). VE estimates against symptomatic infection during months 1 and 7 for mRNA-1273 compared with BNT162b2 were 89.7% (95% CI, 84.4%-93.0%) and 57.3% (95% CI, 48.4%-64.7%) vs 81.6% (95% CI, 75.9%-85.9%) and 22.5% (95% CI, 7.2%-35.2%) for individuals age <65 years and 78.4% (95% CI, 71.1%-83.9%) and 36.2% (95% CI, 27.7%-43.6%) vs 66.3% (95% CI, 55.7%-74.4%) and -23.3% (95% CI, -40.5% to -8.2%) in subjects age ≥65 years; against hospitalization 92.0% (95% CI, 76.1%-97.3%) and 83.1% (95% CI, 66.8%-91.4%) vs 85.6% (95% CI, 72.6%-92.4%) and 57.0% (95% CI, 31.2%-73.2%) in subjects age <65 years and 66.1% (95% CI, 45.3%-79.0%) and 64.7% (95% CI, 55.2%-72.3%) vs 61.0% (95% CI, 41.3%-74.2%) and 1.7% (95% CI, -22.0% to 20.8%) in those age ≥65 years; against ICU admission or death 89.2% (95% CI, 49.5%-97.7%) and 84.4% (95% CI, 59.0%-94.1%) vs 87.6% (95% CI, 61.0%-96.1%) and 66.4% (95% CI, 7.7%-87.8%) in subjects age <65 years and 75.4% (95% CI, 51.7%-87.5%) and 73.8 (95% CI, 62.9%-81.5%) vs 67.4% (95% CI, 32.6%-84.3%) and 29.3% (95% CI, 2.3%-48.9%) in subjects age ≥65 years, respectively (P _interaction < .01 for all comparisons). Similarly, mRNA-1273 was more effective than BNT162b2 in veterans with >1 chronic disease.

Conclusions

mRNA-1273 was more effective than BNT162b2 in older veterans and those with chronic diseases.

COVID-19 disease severity in US Veterans infected during Omicron and Delta variant predominant periods

The SARS-CoV-2 Omicron variant is thought to cause less severe disease among the general population, but disease severity among at-risk populations is unknown. We performed a retrospective analysis using a matched cohort of United States veterans to compare the disease severity of subjects infected during Omicron and Delta predominant periods within 14 days of initial diagnosis. We identified 22,841 matched pairs for both periods. During the Omicron period, 20,681 (90.5%) veterans had mild, 1308 (5.7%) moderate, and 852 (3.7%) severe disease. During the Delta predominant period, 19,356 (84.7%) had mild, 1467 (6.4%) moderate, and 2018 (8.8%) severe disease. Moderate or severe disease was less likely during the Omicron period and more common among older subjects and those with more comorbidities. Here we show that infection with the Omicron variant is associated with less severe disease than the Delta variant in a high-risk older veteran population, and vaccinations provide protection against severe or critical disease.

Outcomes among patients with breakthrough SARS-CoV-2 infection after vaccination in a high-risk national population

BACKGROUND

Breakthrough infections after SARS-CoV-2 infection have been reported. Clinical outcomes among persons with breakthrough infection are not known.

METHODS

We retrospectively identified all Veterans with a confirmed SARS-CoV-2 infection >14 days after the second dose of either Pfizer-BNT-162b2 or Moderna-mRNA-1273 vaccine between December 15, 2020 and March 30, 2021, and age, race, sex, body mass index, Charlson comorbidity index, geographical location, and date of positive test matched unvaccinated controls with SARS-CoV-2 infection. Our primary endpoint was the rate or severe disease defined as hospitalization, mechanical ventilation, or death in both groups.

FINDINGS

Among 258,716 persons with both doses of vaccines and 756,150 without any vaccination, we identified 271 (0.1%) vaccinated persons with breakthrough infection and 48,114 (6.4%) unvaccinated matched controls with infection between December 15, 2020 and March 30, 2021. Among 213 matched pairs, symptoms were present in 33.3% of those with breakthrough infection and 42.2% of the controls. A total of 79 persons met the definition of severe disease or death (42 in the breakthrough infection group and 37 in the control group). Rate of severe disease or death per 1,000 person-days (95% CI) was 4.08 (2.64,5.31) among those with breakthrough infection and 3.6 (2.53,4.73) among the controls (P = 0.58). Rate was similar among both groups regardless of age-group, race, BMI or presence of comorbidities. Among persons with breakthrough infection and matched controls with infection, vaccination was not associated with a lower risk of severe disease or death in the main analyses but was associated with a lower risk when matching did not include geographic location (HR 0.62, 95% CI 0.43,0.91).

INTERPRETATION

Demographic or clinical factors are not associated with a lower risk of severe disease or death in persons with breakthrough SARS-CoV-2 infection.

FUNDING

None.

SARS-CoV-2 Vaccine Effectiveness in a High-Risk National Population in a Real-World Setting

BACKGROUND

With the emergency use authorization of multiple vaccines against SARS-CoV-2 infection, data are urgently needed to determine their effectiveness in a real-world setting.

OBJECTIVE

To evaluate the short-term effectiveness of vaccines in preventing SARS-CoV-2 infection.

DESIGN

Test-negative case-control study using conditional logistic regression.

SETTING

U.S. Department of Veterans Affairs health care system.

PARTICIPANTS

All veterans who had testing for SARS-CoV-2 infection between 15 December 2020 and 4 March 2021 and no confirmed infection before 15 December 2020.

INTERVENTION

SARS-CoV-2 vaccination with either the BNT-162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine as part of routine clinical care.

MEASUREMENTS

Effectiveness of vaccination against confirmed SARS-CoV-2 infection.

RESULTS

Among 54 360 persons who tested positive and 54 360 propensity score-matched control participants, the median age was 61 years, 83.6% were male, and 62% were White. Median body mass index was 31 kg/m² among those who tested positive and 30 kg/m² among those who tested negative. Among those who tested positive, 9800 (18.0%) had been vaccinated; among those who tested negative, 17 825 (32.8%) had been vaccinated. Overall vaccine effectiveness 7 or more days after the second dose was 97.1% (95% CI, 96.6% to 97.5%). Effectiveness was 96.2% (CI, 95.5% to 96.9%) for the Pfizer-BioNTech BNT-162b2 vaccine and 98.2% (CI, 97.5% to 98.6%) for the Moderna mRNA-1273 vaccine. Effectiveness remained above 95% regardless of age group, sex, race, or presence of comorbidities.

LIMITATIONS

Predominantly male population; lack of data on disease severity, mortality, and effectiveness by SARS-CoV-2 variants of concern; and short-term follow-up.

CONCLUSION

Currently used vaccines against SARS-CoV-2 infection are highly effective in preventing confirmed infection in a high-risk population in a real-world setting.

PRIMARY FUNDING SOURCE

None.

Interleukin-6 Receptor Antagonists in Critically Ill Patients with Covid-19

BACKGROUND

The efficacy of interleukin-6 receptor antagonists in critically ill patients with coronavirus disease 2019 (Covid-19) is unclear.

METHODS

We evaluated tocilizumab and sarilumab in an ongoing international, multifactorial, adaptive platform trial. Adult patients with Covid-19, within 24 hours after starting organ support in the intensive care unit (ICU), were randomly assigned to receive tocilizumab (8 mg per kilogram of body weight), sarilumab (400 mg), or standard care (control). The primary outcome was respiratory and cardiovascular organ support-free days, on an ordinal scale combining in-hospital death (assigned a value of -1) and days free of organ support to day 21. The trial uses a Bayesian statistical model with predefined criteria for superiority, efficacy, equivalence, or futility. An odds ratio greater than 1 represented improved survival, more organ support-free days, or both.

RESULTS

Both tocilizumab and sarilumab met the predefined criteria for efficacy. At that time, 353 patients had been assigned to tocilizumab, 48 to sarilumab, and 402 to control. The median number of organ support-free days was 10 (interquartile range, -1 to 16) in the tocilizumab group, 11 (interquartile range, 0 to 16) in the sarilumab group, and 0 (interquartile range, -1 to 15) in the control group. The median adjusted cumulative odds ratios were 1.64 (95% credible interval, 1.25 to 2.14) for tocilizumab and 1.76 (95% credible interval, 1.17 to 2.91) for sarilumab as compared with control, yielding posterior probabilities of superiority to control of more than 99.9% and of 99.5%, respectively. An analysis of 90-day survival showed improved survival in the pooled interleukin-6 receptor antagonist groups, yielding a hazard ratio for the comparison with the control group of 1.61 (95% credible interval, 1.25 to 2.08) and a posterior probability of superiority of more than 99.9%. All secondary analyses supported efficacy of these interleukin-6 receptor antagonists.

CONCLUSIONS

In critically ill patients with Covid-19 receiving organ support in ICUs, treatment with the interleukin-6 receptor antagonists tocilizumab and sarilumab improved outcomes, including survival. (REMAP-CAP ClinicalTrials.gov number, NCT02735707.).

Feasibility of a Home-Based Palliative Care Intervention for Elderly Multimorbid Survivors of Critical Illness

BACKGROUND

Elderly patients frequently experience deteriorating health after critical illness, which may threaten their independence and predispose them to unplanned hospital readmissions and premature death.

OBJECTIVES

To evaluate the operational feasibility of a 90-day home-based palliative care intervention in multimorbid elderly Veteran survivors of critical illness.

METHODS

A multidisciplinary home-based palliative care intervention was provided for multimorbid elderly veterans who were discharged home after admission to the intensive care unit for sepsis, pneumonia, heart failure, or exacerbation of chronic obstructive lung disease.

RESULTS

Fifteen patients enrolled in the study, 11 (73%) of whom completed all visits; thus the prespecified goal of >70% completion was met. Median (interquartile range [IQR]) age of the patients was 76 (69-87) years. Participants had a median (IQR) of 8 (7-8) concurrent chronic health conditions, were moderately debilitated at baseline, and were all male. The median (IQR) time to the first study visit was 8 (5-12) days. Patients had a median (IQR) of 8 (5-11) in-home visits and 6 (3-7) telephone encounters during the 90-day study period. Nurses spent a median (IQR) cumulative time of 330 (240-585) minutes on home visits and 30 (10-70) minutes on telephone visits. The median (IQR) time per home provider visit was 90 (75-90) minutes. We estimated the median (IQR) cost per patient to be $2321 ($1901-$3331).

CONCLUSION

A comprehensive home-based palliative care intervention is operationally feasible in elderly multi-morbid survivors of critical illness and may result in improved physical functioning and quality of life and fewer unplanned emergency department visits.

Immune checkpoint inhibition in sepsis: a Phase 1b randomized study to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of nivolumab

PURPOSE

Sepsis-associated immunosuppression increases hospital-acquired infection and viral reactivation risk. A key underlying mechanism is programmed cell death protein-1 (PD-1)-mediated T-cell function impairment. This is one of the first clinical safety and pharmacokinetics (PK) assessments of the anti-PD-1 antibody nivolumab and its effect on immune biomarkers in sepsis.

METHODS

Randomized, double-blind, parallel-group, Phase 1b study in 31 adults at 10 US hospital ICUs with sepsis diagnosed ≥ 24 h before study treatment, ≥ 1 organ dysfunction, and absolute lymphocyte count ≤ 1.1 × 10³ cells/μL. Participants received one nivolumab dose [480 mg (n = 15) or 960 mg (n = 16)]; follow-up was 90 days. Primary endpoints were safety and PK parameters.

RESULTS

Twelve deaths occurred [n = 6 per study arm; 40% (480 mg) and 37.5% (960 mg)]. Serious AEs occurred in eight participants [n = 1, 6.7% (480 mg); n = 7, 43.8% (960 mg)]. AEs considered by the investigator to be possibly drug-related and immune-mediated occurred in five participants [n = 2, 13.3% (480 mg); n = 3, 18.8% (960 mg)]. Mean ± SD terminal half-life was 14.7 ± 5.3 (480 mg) and 15.8 ± 7.9 (960 mg) days. All participants maintained > 90% receptor occupancy (RO) 28 days post-infusion. Median (Q1, Q3) mHLA-DR levels increased to 11,531 (6528, 19,495) and 11,449 (6225, 16,698) mAbs/cell in the 480- and 960-mg arms by day 14, respectively. Pro-inflammatory cytokine levels did not increase.

CONCLUSIONS

In this sepsis population, nivolumab administration did not result in unexpected safety findings or indicate any 'cytokine storm'. The PK profile maintained RO > 90% for ≥ 28 days. Further efficacy and safety studies are warranted. TRIAL REGISTRATION NUMBER (CLINICALTRIALS.GOV): NCT02960854.

Children with Chronic Disease Bear the Highest Burden of Pediatric Sepsis

OBJECTIVE

To describe the contemporary epidemiology of pediatric sepsis in children with chronic disease, and the contribution of chronic diseases to mortality. We examined the incidence and hospital mortality of pediatric sepsis in a nationally representative sample and described the contribution of chronic diseases to hospital mortality.

STUDY DESIGN

We analyzed the 2013 Nationwide Readmissions Database using a retrospective cohort design. We included non-neonatal patients <19 years of age hospitalized with sepsis. We examined patient characteristics, the distribution of chronic disease, and the estimated national incidence, and described hospital mortality. We used mixed effects logistic regression to explore the association between chronic diseases and hospital mortality.

RESULTS

A total of 16 387 admissions, representing 14 243 unique patients, were for sepsis. The national incidence was 0.72 cases per 1000 per year (54 060 cases annually). Most (68.6%) had a chronic disease. The in-hospital mortality was 3.7% overall-0.7% for previously healthy patients and 5.1% for patients with chronic disease. In multivariable analysis, oncologic, hematologic, metabolic, neurologic, cardiac and renal disease, and solid organ transplantation were associated with increased in-hospital mortality.

CONCLUSIONS

More than 2 of 3 children admitted with sepsis have ≥1 chronic disease and these patients have a higher in-hospital mortality than previously healthy patients. The burden of sepsis in hospitalized children is greatest in pediatric patients with chronic disease.

Reparixin, a Specific Interleukin-8 Inhibitor, Has No Effects on Inflammation during Endotoxemia

Reparixin antagonizes interleukin-8 (IL-8) on the level of signal transduction in vitro. We hypothesized that IL-8 mediates some of the reactions occurring during acute inflammation and specifically that IL-8 may be a mediator of endotoxin induced neutrophilia. We therefore tested the effects of reparixin on humoral and cellular parameters in LPS-induced acute systemic inflammation. The study is a randomized (3:2 active:placebo), double-blind, placebo-controlled parallel group trial. Twenty healthy male volunteers randomly received either reparixin (12) or placebo (8) intravenously. One hour after the start of reparixin/placebo infusion a bolus of 2 ng/kg endotoxin was infused over 1–2 min. Blood samples were obtained over 24 h. Reparixin, being metabolized to ibuprofen, suppressed serum thromboxane B2 levels by 78% compared to baseline and control at 8 h. LPS-induced neutrophilia was not significantly affected by reparixin in human volunteers. Consistently, reparixin did not alter the lymphocyte or monocyte counts and had no effect on LPS-induced systemic inflammation as measured by tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6) release. Regulation of IL-8 receptors CXCR1 and 2 and the degranulation marker CD11b showed the expected kinetics. Reparixin had no effect on thrombin formation as measured by prothrombin fragment (F1+2). In conclusion, our study showed that reparixin was safe but had no impact on endotoxin induced inflammation. In contrast to previous studies with its metabolite ibuprofen, reparixin does not enhance inflammation in this model.

Socioeconomic factors associated with outcome after cardiac arrest in patients under the age of 65

AIM

In a prior study of seven North American cities Pittsburgh had the highest crude rate of cardiac arrest deaths in patients 18 to 64 years of age, particularly in neighborhoods with lower socioeconomic status (SES). We hypothesized that lower SES, associated poor health behaviors (e.g., illicit drug use) and pre-existing comorbid conditions (grouped as socioeconomic factors [SE factors]) could affect the type and severity of cardiac arrest, thus outcomes.

METHODS

We retrospectively identified patients aged 18 to 64 years treated for in-hospital (IHCA) and out-of hospital arrest (OHCA) at two Pittsburgh hospitals between January 2010 and July 2012. We abstracted data on baseline demographics and arrest characteristics like place of residence, insurance and employment status. Favorable cerebral performance category [CPC] (1 or 2) was our primary outcome. We examined the associations between SE factors, cardiac arrest variables and outcome as well as post-resuscitation care.

RESULTS

Among 415 subjects who met inclusion criteria, unfavorable CPC were more common in patients who were unemployed, had a history of drug abuse or hypertension. In OHCA, favorable CPC was more often associated with presentation with ventricular fibrillation/tachycardia (OR 3.53, 95% CI 1.43-8.74, p = 0.006) and less often associated with non-cardiovascular arrest etiology (OR 0.22, 95% CI 0.08-0.62, p = 0.004). We found strong associations between specific SE factors and arrest factors associated with outcome in OHCA patients only. Significant differences in post-resuscitation care existed based on injury severity, not on SES.

CONCLUSIONS

SE factors strongly influence type and severity of OHCA but not IHCA resulting in an association with outcomes.

Quality of post arrest care does not differ by time of day at a specialized resuscitation center

Previous studies suggest worse outcomes after out-of-hospital cardiac arrest (OHCA) at night. We analyzed whether patients admitted after nontraumatic OHCA to a resuscitation center received the same quality post arrest care at day and night and whether quality of care affected clinical outcomes. We analyzed data of OHCA patients with return of spontaneous circulation admitted to the Vienna general hospital emergency department between January 2006 and May 2013. Data reported include admission time (day defined from 8 AM to 4 PM based on staffing), time to initiation of hypothermia, and door-to-balloon time in patients with ST-elevation myocardial infarction. Survival and cognitive performance at 12 months were assessed. In this retrospective observational study, 1059 patients (74% males, n = 784) with a mean age of 58 ± 16 years were analyzed. The vast majority was treated with induced hypothermia (77% of day vs. 79% of night admissions, P = 0.32) within 1 hour of admission (median time admission to cooling 27 (confidence interval [CI]: 10-60) vs. 23 (CI: 11-59) minutes day vs. night, P = 0.99). In 298 patients with ST-elevation myocardial infarction, median door-to-balloon time did not differ between day and night admissions (82 minutes, CI: 60 to 142 for day vs. 86 minutes, CI: 50 to 135 for night, P = 0.36). At 12 months, survival was recorded in 238 of 490 day and 275 of 569 night admissions (49% vs. 48%, P = 0.94%), and a good neurologic outcome was recorded in 210 of 490 day and 231 of 569 night admissions (43% vs. 41%, P = 0.46). Patients admitted to our department after OHCA were equally likely to receive timely high-quality postresuscitation care irrespective of time of day. Survival and good neurologic outcome at 12 months did not differ between day and night admissions. Our results may support the concept of specialized post arrest care centers.

Prehospital surface cooling is safe and can reduce time to target temperature after cardiac arrest

PURPOSE

Mild therapeutic hypothermia proved to be beneficial when induced after cardiac arrest in humans. Prehospital cooling with i.v. fluids was associated with adverse side effects. Our primary objective was to compare time to target temperature of out-of hospital cardiac arrest patients cooled non-invasively either in the prehospital setting vs. the in-hospital (IH) setting, to assess surface-cooling safety profile and long term outcome.

METHODS

In this retrospective, single center cohort study, a group of adult patients with restoration of spontaneous circulation (ROSC) after out-of hospital cardiac arrest were cooled with a surface cooling pad beginning either in the prehospital or IH setting for 24h. Time to target temperature (33.9°C), temperature on admission, time to admission after ROSC and outcome were compared. Also, rearrests and pulmonary edema were assessed. Neurologic outcome at 12 months was evaluated (Cerebral Performance Category, CPC 1-2, favorable outcome).

RESULTS

Between September 2005 and February 2010, 56 prehospital cooled patients and 54 IH-cooled patients were treated. Target temperature was reached in 85 (66-117)min (prehospital) and in 135 (102-192)min (IH) after ROSC (p<0.001). After prehospital cooling, hospital admission temperature was 35.2 (34.2-35.8)°C, and in the IH-cooling patients initial temperature was 35.8 (35.2-36.3)°C (p=0.001). No difference in numbers of rearrests and pulmonary edema between groups was observed. In both groups, no skin lesions were observed. Favorable outcome was reached in 26.8% (prehospital) and in 37.0% (IH) of the patients (p=0.17).

CONCLUSIONS

Using a non-invasive prehospital surface cooling method after cardiac arrest, target temperature can be reached faster without any major complications than starting cooling IH. The effect of early non-invasive cooling on long-term outcome remains to be determined in larger studies.

MMP-8 genotypes influence the inflammatory response in human endotoxemia

Clinical studies have reported associations between MMP-8 genotypes and clinical outcomes without exploring underlying mechanisms. This study aims to understand the influence of the rs1940475 SNP on downstream chemokine and cytokine response in human endotoxemia. Rs1940475 was genotyped in 44 healthy Caucasian males, who were challenged with an intravenous bolus of 2 ng/kg lipopolysaccharide (LPS). Plasma levels of tumor necrosis factor (TNF), interleukin (IL)-6, IL-8, and macrophage inflammatory protein (MIP)-1α were measured at baseline and 2, 4, 6, and 24 h after LPS infusion with high-sensitivity enzyme immunoassays. Peak TNF levels at 2 h after LPS infusion were significantly higher in subjects with AA genotype compared to subjects with AG or GG genotypes (185 pg/mL [IQR, 154–234] vs. 94 pg/mL [IQR, 65–125] vs. 107 pg/mL [IQR, 80–241], respectively; p = 0.03 between groups). Peak IL-6 levels were trend-wise higher in subjects with AA genotype compared to those with AG or GG genotypes (566 pg/mL [IQR, 294–644] vs. 278 pg/mL [IQR, 184–539] and 329 pg/mL [IQR, 240–492], respectively; p = 0.15 between groups). In contrast, peak MIP-1α at 2 h was highest in GG genotype carriers compared to those with AG or AA genotypes (602 pg/mL [IQR, 449–727] vs. 389 pg/mL [IQR, 375–490] and 510 pg/mL [425–813], respectively; p < 0.03 between groups). AA genotype carriers had highest peak TNF and IL-6 levels after LPS challenge, whereas peak MIP-1α levels were highest in GG carriers. This indicates that the rs1940475 SNP modifies the host response to inflammatory stimuli, which may in part explain previously shown associations with clinical outcomes.

Decreased renal function in hypertensive emergencies

Data about acute renal function in hypertensive crises are scarce. We hypothesised that acute kidney damage could result from hypertensive emergency (HE), as indicated by the earliest biomarker of kidney injury, neutrophil gelatinase-associated lipocalin (NGAL). Thus, we compared renal function between patients with HE, patients with urgencies and normotensive controls. Sixty emergency department patients were enroled in a prospective, cross-sectional study. Creatinine, blood urea nitrogen (BUN), NGAL and cystatin C were measured and estimated glomerular filtration rate was calculated (eGFR). Creatinine and BUN were significantly higher and eGFR was significantly lower in HE as compared with urgencies or controls (P < 0.01). Similarly, cystatin C and NGAL levels were significantly higher in emergencies compared with the other groups (P < 0.001). All renal function parameters were similar between urgencies and controls. Among HE, NGAL was significantly higher (61%) in patients with pulmonary oedema than in those with cerebral events (P = 0.008), whereas the other parameters were not significantly different. In conclusion, this cross-sectional investigation showed that markers of acute and chronic kidney injury were higher in patients with HE than in urgencies or controls. These results should encourage further studies to better characterise the role of acute kidney damage in hypertensive pulmonary oedema, and HE in general.

Epidemiology of severe sepsis

Severe sepsis is a leading cause of death in the United States and the most common cause of death among critically ill patients in non-coronary intensive care units (ICU). Respiratory tract infections, particularly pneumonia, are the most common site of infection, and associated with the highest mortality. The type of organism causing severe sepsis is an important determinant of outcome, and gram-positive organisms as a cause of sepsis have increased in frequency over time and are now more common than gram-negative infections.

Recent studies suggest that acute infections worsen pre-existing chronic diseases or result in new chronic diseases, leading to poor long-term outcomes in acute illness survivors. People of older age, male gender, black race, and preexisting chronic health conditions are particularly prone to develop severe sepsis; hence prevention strategies should be targeted at these vulnerable populations in future studies.

Androgen deprivation decreases prostate specific antigen in the absence of tumor: implications for interpretation of PSA results

Background: Prostate-specific antigen (PSA) is used as an outcome measure for relapsed disease in prostate cancer. Nonetheless, there are considerable concerns about its indiscriminate use as a surrogate endpoint for cell growth or survival. We hypothesized that treatment with a luteinizing hormone releasing hormone (LHRH) analog would decrease PSA levels even in the absence of malignant disease.

Methods: We determined testosterone and PSA levels in 30 healthy volunteers after a single intramuscular injection of a LHRH depot formulation. Testosterone and PSA levels were quantified by radioimmunoassay and electrochemi-luminescence immunoassay, respectively.

Results: After an initial flare-up during the first 3 days testosterone decreased reaching castration levels in 18 of the 30 young men (60%). After the nadir on day 28, testosterone levels increased to normal again. Changes in PSA paralleled those of testosterone. Castration reduced PSA levels by 29% (95% CI 19%–39%) compared to baseline (p<0.0001).

Conclusions: LHRH superagonists decrease PSA levels by testosterone deprivation. Conferring these findings to tumor patients, decreases in PSA after treatment with LHRH analogs might not only reflect disease regression but also a direct testosterone mediated effect on PSA. Thus, PSA levels should be cautiously interpreted when patients receive hormonal therapy.

Hypokalemic paralysis in a professional bodybuilder

Severe hypokalemia is a potentially life-threatening disorder and is associated with variable degrees of skeletal muscle weakness, even to the point of paralysis. On rare occasions, diaphragmatic paralysis from hypokalemia can lead to respiratory arrest. There may also be decreased motility of smooth muscle, manifesting with ileus or urinary retention. Rarely, severe hypokalemia may result in rhabdomyolysis. Other manifestations of severe hypokalemia include alteration of cardiac tissue excitability and conduction. Hypokalemia can produce electrocardiographic changes such as U waves, T-wave flattening, and arrhythmias, especially if the patient is taking digoxin. Common causes of hypokalemia include extrarenal potassium losses (vomiting and diarrhea) and renal potassium losses (eg, hyperaldosteronism, renal tubular acidosis, severe hyperglycemia, potassium-depleting diuretics) as well as hypokalemia due to potassium shifts (eg, insulin administration, catecholamine excess, familial periodic hypokalemic paralysis, thyrotoxic hypokalemic paralysis). Although the extent of diuretic misuse in professional bodybuilding is unknown, it may be regarded as substantial. Hence, diuretics must always be considered as a cause of hypokalemic paralysis in bodybuilders.

Infection rate and acute organ dysfunction risk as explanations for racial differences in severe sepsis

CONTEXT

Severe sepsis, defined as infection complicated by acute organ dysfunction, occurs more frequently and leads to more deaths in black than in white individuals. The optimal approach to minimize these disparities is unclear.

OBJECTIVE

To determine the extent to which higher severe sepsis rates in black than in white patients are due to higher infection rates or to a higher risk of acute organ dysfunction.

DESIGN, SETTING, AND PARTICIPANTS

Analysis of infection-related hospitalizations from the 2005 hospital discharge data of 7 US states and infection-related emergency department visits from the 2003-2007 National Hospital Ambulatory Care Survey.

MAIN OUTCOME MEASURE

Age- and sex-standardized severe sepsis and infection hospitalization rates and the risk of acute organ dysfunction.

RESULTS

Of 8,661,227 non-childbirth-related discharges, 2,261,857 were associated with an infection, and of these, 381,787 (16.8%) had severe sepsis. Black patients had a 67% higher age- and sex-standardized severe sepsis rate than did white patients (9.4; 95% confidence interval [CI], 9.3-9.5 vs 5.6; 95% CI, 5.6-5.6 per 1000 population; P < .001) and 80% higher standardized mortality (1.8, 95% CI, 1.8-1.9 vs 1.0, 95% CI, 1.0-1.1 per 1000 population; P < .001). The higher severe sepsis rate was explained by both a higher infection rate in black patients (47.3; 95% CI, 47.1-47.4 vs 34.0; 95% CI, 33.9-34.0 per 1000 population; incidence rate ratio, 1.39; P < .001) and a higher risk of developing acute organ dysfunction (age- and sex-adjusted odds ratio [OR], 1.29; 95% CI, 1.27-1.30; P < .001). Differences in infection presented broadly across different sites and etiology of infection and for community- and hospital-acquired infections and occurred despite a lower likelihood of being admitted for infection from the emergency department (adjusted OR, 0.70; 95% CI, 0.64-0.76; P < .001). The higher risk of organ dysfunction persisted but was attenuated after adjusting for age, sex, comorbid conditions, poverty, and hospital effect (OR, 1.14; 95% CI, 1.13-1.16; P < .001). Racial disparities in infection and severe sepsis incidence and mortality rates were largest among younger adults (eg, the proportion of invasive pneumococcal disease occurring in adults < 65 years was 73.9% among black patients vs 44.5% among white patients, P < .001).

CONCLUSION

Racial differences in severe sepsis are explained by both a higher infection rate and a higher risk of acute organ dysfunction in black than in white individuals.

The aptamer ARC1779 blocks von Willebrand factor-dependent platelet function in patients with thrombotic thrombocytopenic purpura ex vivo

BACKGROUND

In thrombotic thrombocytopenic purpura (TTP), ultralarge von Willebrand factor (VWF) multimers bind platelet (PLT) glycoprotein Ib and lead to the formation of disseminated fibrin-poor, VWF-rich PLT thrombi. The aptamer ARC1779 blocks binding of the VWF A1 domain to PLT glycoprotein Ib. We evaluated whether ARC1779 inhibits the excessive VWF activity and VWF-mediated PLT function in patients with TTP.

STUDY DESIGN AND METHODS

We studied the ex vivo concentration response curves for ARC1779 on PLT function analyzer (PFA-100, Dade Behring) and cone-and-plate analyzer (CPA, Impact-R) PLT function tests, agonist-induced PLT aggregation, and VWF activity of TTP patients (n = 11, three in acute phase and eight in remission) and healthy controls (n = 44).

RESULTS

VWF activity and VWF-dependent PLT plug formation were increased in TTP patients relative to healthy controls, but agonist-induced PLT aggregation was not. ARC1779 blocked collagen/adenosine 5'-diphosphate (ADP)-induced PLT plug formation as measured by PFA-100 with an inhibitory concentration (IC)(100) of approximately 1 microg/mL in citrate-anticoagulated samples and approximately 3 to 4 microg/mL in hirudin-anticoagulated samples. A similar concentration of ARC1779 was necessary to block shear-dependent PLT adhesion in both TTP patients and healthy controls using the CPA assay (IC(100) of approx. 1 microg/mL for both). ARC1779 blocked VWF activity with an IC(90) of approximately 3 to 4 microg/mL in all subjects, but did not inhibit PLT aggregation by ADP, collagen, or arachidonic acid even at concentrations much greater than those that fully inhibited VWF-dependent PLT function.

CONCLUSIONS

ARC1779 potently and specifically inhibits VWF activity and VWF-dependent PLT function. ARC1779 may be a promising novel therapeutic for the treatment of TTP.

The aptamer ARC1779 is a potent and specific inhibitor of von Willebrand Factor mediated ex vivo platelet function in acute myocardial infarction

ARC1779 is an aptamer, which blocks binding of the von Willebrand Factor (VWF) A1 domain to platelet GPIb receptors. VWF is increased in the elderly an in the setting of acute myocardial infarction (AMI), as reflected by increased shear-dependent platelet function. We hypothesized that ARC1779 concentration-dependently inhibits ex vivo platelet function, and that this concentration effect relationship may be shifted in patients with AMI. We studied ex vivo dose response curves for ARC1779 on VWF activity, shear-dependent platelet function, and agonist-induced platelet aggregation. We included patients with AMI on standard treatment (n = 40), young (n = 20) and elderly controls (n = 20) in this ex vivo dosing study. AMI patients displayed approximately 2-fold increased plasma levels of VWF activity as compared to controls. ARC1779 inhibited VWF activity (IC90: approximately 3-4 microg/mL) and shear dependent platelet function (Platelet Function Analyzer (PFA-100), IC50: approximately 0.5-0.9 microg/mL and Cone and Plate Analyzer (CPA), IC50: approximately 0.1-0.4 microg/mL in citrated blood) at comparable concentrations in all groups. In contrast to GPIIb/IIIa antagonists, ARC1779 did not inhibit platelet aggregation induced by ADP, collagen or arachidonic acid at concentrations (10 microg/mL) that fully inhibited VWF dependent platelet function. ARC1779 potently and specifically inhibits VWF activity and VWF dependent platelet function, even in the setting of AMI where VWF activity is increased.

Racial differences in endotoxin-induced tissue factor-triggered coagulation

BACKGROUND

Racial differences in coagulation are poorly understood. While some studies suggest a 'prothrombotic' coagulation profile in blacks compared with whites, others report an increased bleeding risk for blacks in various clinical settings. Moreover, preclinical data suggest a link between the Duffy antigen (=DARC, Duffy antigen receptor of chemokines) and coagulation.

OBJECTIVES

Based on our previous research in Duffy antigen negative Africans, we hypothesized that Africans have an attenuated procoagulant response compared with Caucasians in a model of lipopolysaccharide (LPS)-induced, tissue factor (TF)-triggered coagulation activation.

PATIENTS/METHODS

Healthy male volunteers (16 Duffy-negative Africans, 16 Duffy-positive Caucasians) received 2 ng kg(-1) LPS, and outcome parameters were measured using enzyme immunoassays and real-time polymerase chain reaction (RT-PCR, Taqman).

RESULTS

LPS increased microparticle (MP)-associated TF procoagulant activity (PCA) less in Africans than Caucasians. Africans had reduced in vivo thrombin formation compared with Caucasians: they generated less thrombin-antithrombin (TAT) complexes (10.4 pg mL(-1) vs. 23.0 pg mL(-1), P<0.0001) and less prothrombin fragments (F1+2) (337 pmol mL(-1) vs. 819 pmol mL(-1), P<0.0001). Consistently, Africans also had decreased fibrin formation (D-dimer: 0.3 pg mL(-1) vs. 0.5 pg mL(-1), P=0.02).

CONCLUSION

Duffy-negative subjects of African descent have a markedly reduced procoagulant response in a model of LPS-induced, TF-triggered coagulation activation compared with Duffy-positive healthy Caucasians.

Effects of the pan-selectin antagonist bimosiamose (TBC1269) in experimental human endotoxemia

Selectins mediate the adhesion of leukocytes to activated endothelial cells and activated platelets. In addition to these cell-to-cell interactions, they influence the fibrin content and size of venous thrombi in different animal models. However, the exact role of selectins in human endotoxemia still remains unclear. We aimed to investigate the effect of selectin inhibition in lipopolysaccharide (LPS)-induced tissue factor (TF)-dependent activation of coagulation in a well-standardized model of human endotoxemia. To explore whether selectin blockade attenuates LPS-induced coagulation in humans, we performed a randomized, double-bind placebo-controlled crossover trial in 16 healthy male volunteers. All subjects received 2 ng/kg of LPS and, 10 min thereafter, a 15-min infusion of either 30 mg/kg of the pan-selectin antagonist bimosiamose or equal volumes of placebo in random order, with a washout period of 6 weeks between both periods. Treatment with bimosiamose had no significant effect on LPS-induced TF expression, as quantified by TF mRNA levels, or on LPS-induced coagulation response, reflected by increases in plasma thrombin-antithrombin (TAT) complexes and prothrombin fragment (F1 + 2) levels. Furthermore, bimosiamose did not affect the LPS-dependent changes in leukocyte subpopulations or the increase in platelet-leukocyte aggregates, as determined in the level of CD41+ monocytes. Finally, neither the LPS-induced release of tumor necrosis factor, interleukin 6, leukocyte expression of CD11b, nor intercellular adhesion molecule 1 were affected by administration of bimosiamose. The pan-selectin antagonist bimosiamose does not attenuate TF-triggered coagulation or inflammation in human endotoxemia. This indicates a minor influence of this selectin antagonist in this model. In addition, infusion of bimosiamose was safe and well tolerated in human endotoxemia.

Effects of low dose endotoxemia on endothelial progenitor cells in humans

BACKGROUND

Endothelial progenitor cells (EPCs) are a specific subtype of hematopoietic stem cells that migrate from the bone marrow to the peripheral circulation where they contribute to the repair of injured endothelium and to the formation of new blood vessels. Levels of circulating EPCs have been investigated in different inflammatory disease states. However, data on circulating EPC levels and systemic inflammation remain scarce and contradictory.

OBJECTIVE

We investigated a putative relationship of low grade experimental endotoxemia to changes in circulating EPC levels.

METHODS

Randomized, double-blind, placebo-controlled parallel group trial in 36 healthy male volunteers. Thirty-two volunteers received 2 ng/kg LPS intravenously, the remaining four an equal volume of physiologic saline solution as placebo.

RESULTS

Endothelial progenitor cells showed a significant decrease over the observation period among the 32 subjects challenged with LPS (P<0.0001) and reached their nadir at 6 h, with a median decrease of 62% (interquartile range: 48-81%) compared with baseline levels. Circulating EPCs returned to values comparable to baseline 24 h after LPS challenge.

CONCLUSION

Infusion of 2 ng/kg LPS led to a significant decrease in peripheral EPCs. These results suggest that the early phase of acute inflammation is associated with a decrease in peripheral EPCs.

Pharmacokinetics and Pharmacodynamics of the Dual FII/FX Inhibitor BIBT 986 in Endotoxin-induced Coagulation

BIBT986 is a dual inhibitor of factors Xa and IIa. The aim of this study was to compare with placebo the effect of three doses of BIBT986 on coagulation, platelet activation, and inflammation. This was a prospective, randomized, double-blind, placebo-controlled, parallel-group dose escalation trial in 48 healthy male volunteers. Participants received one of three doses of BIBT986 or placebo intravenously together with a bolus infusion of 2 ng/kg lipopolysaccharide (LPS). BIBT986 dose-dependently changed global coagulation parameters and in vivo markers of thrombin generation and action: BIBT986 doses, which prolonged activated partial thromboplastin time by 100%, completely suppressed the LPS-induced increases in prothrombin fragment, thrombin-antithrombin complexes, and D-dimer, which were 6.1-, 14.5, and 3.5-fold in the placebo group, respectively. BIBT986 did not influence inflammation, fibrinolysis, or platelet activation. Therefore, BIBT986 is a potent anticoagulant in the human endotoxemia model.

Current developments in anti-platelet therapy

Platelets play a life-saving role in hemostasis and blood clotting at sites of vascular injury and consequently are similarly involved in the pathological counterpart, namely thrombosis. Thus, anti-platelet therapy has become a mainstay in treatment and/or prophylaxis of conditions like myocardial infarction, stroke and other cardiovascular diseases. Acetyl-salicylic acid (ASA, aspirin) is still the most widely used agent and considered as the prototype antiplatelet drug. Since platelet activation occurs via several pathways that are not influenced by ASA, several other compounds have been developed to add to its beneficial effect. Currently four main classes of antiplatelet agents are available for clinical use: acetyl-salicylic acid (ASA), phosphodiesterase (PDE) inhibitors, thienopyridines and the intravenous GPIIb/IIIa antagonists. This article gives a concise review of these four classes of anti-platelet agents, using ASA as the reference standard.

Ethnic differences in plasma levels of interleukin-8 (IL-8) and granulocyte colony stimulating factor (G-CSF)

Ethnic neutropenia is common in people of African descent. As interleukin-8 (IL-8) and granulocyte colony stimulating factor (G-CSF) bind to receptors on neutrophils, ethnic differences in neutrophil counts are hypothesized to result in different plasma levels of these cytokines. A prospective study was conducted in 72 healthy young volunteers. Neutrophil counts were 60% higher in Caucasians (P<0.00001). Average IL-8 and G-CSF levels were about 50% and 70% higher in African volunteers compared with Caucasian volunteers (P=0.0008 and P=0.00005, respectively). Additionally, oxidative burst capacity in stimulated neutrophils was significantly lower in volunteers of African descent (P=0.03 between both groups). In sum, lower neutrophil counts are associated with higher levels of IL-8 and G-CSF in Africans.