Use and outcomes of antihypertensive medication treatment in the US hypertensive population: A gender comparison

Background

Although effective antihypertensive medications have existed for decades, only about half of the hypertensive individuals are considered to have controlled blood pressure. Limited research studies have investigated gender disparity in the utilization and effectiveness of antihypertensive medications treatment. To examine the gender difference in antihypertensive medications' use and the effect of using antihypertensive medication treatment on blood pressure control among the U.S. adult with hypertension.

Methods

Analysis of National Health and Nutrition Examination Survey (NHANES) data from (1999-2012) including individuals≥18 years old with hypertension. Study variables included gender, age, race/ethnicity, obesity, smoking, comorbidities, treatment medication type, and continuity of care. We used multivariate logistic regression in STATA V14. The data is presented as adjusted odds ratios (ORs) and 95% confidence interval (CI).

Results

Of the 15719 participants, 52% were female. 49% of the antihypertensive medication users had their blood pressure under control (95% CI). In the adjusted logistic regression analysis, use of antihypertensive medications was found to be 12% greater in females as compared to males (OR=1.12; CI=1.02-1.22; P<0.05). No association between gender and blood pressure control was found. Blood pressure control was less likely achieved among 50 years or younger individuals, Blacks and Hispanics, obese, and those taking calcium channel blocker (CCB).

Conclusion

Hypertensive females are more likely than males to use antihypertensive medications. The effectiveness of treatment to control blood pressure is equal across males and females. Our findings have implications for practitioners to account gender-specific approaches when discussing adherence to hypertension medication treatment with their patients.

Do surgical drains reduce surgical site occurrence and infection after incisional hernia repair with sublay mesh? A non-randomised pilot study

INTRODUCTION

Surgical site occurrence (SSO) and surgical site infection (SSI) are common concerns with incisional hernia repair. Intraoperative drain placement is a common practice aiming to reduce SSO and SSI rates. However, literature on the matter is very poor. The aim of this study is to investigate the role of subcutaneous and periprosthetic drain placement on postoperative outcomes and SSO and SSI rates with incisional hernia repair.

METHODS

A non-randomised pilot study was performed between January 2018 and December 2020 and included patients with elective midline or lateral incisional hernia repair with sublay mesh placement. Patients were prospectively included, followed for 1 month and divided into three groups: group 1 without drainage, group 2 with subcutaneous drainage, and group 3 with subcutaneous and periprosthetic drains. Drains were placed at surgeon's discretion. All patients were included in the enhanced recovery program.

RESULTS

One hundred and four patients were included. Twenty-four patients (23.1%) did not have drains (group 1), 60 patients (57.7%) had a subcutaneous drain (group 2) and 20 patients (19.2%) had both a subcutaneous and a periprosthetic drains (group 3). SSO rates were significantly different between the 3 groups: 20.8% in group 1, 20.7% in group 2 and 50% in group 3 (p = 0.03). There was no significant difference in deep and superficial SSI rates between the 3 groups. Subgroup analysis revealed that adding a drain in direct contact with the mesh significantly increased SSO rate but did not influence SSI rate. Length of stay was also significantly increased by the presence of a drain, 3.1 ± 1.9 days for group 1; 5.9 ± 4.8 for group 2 and 5.9 ± 2.5 days for group 3 (p < 0.005).

CONCLUSION

Drain placement in direct contact with the mesh might increase SSO rate. More studies are necessary to evaluate the actual benefits of drainage after incisional hernia repair.

More Drug Monitoring and Less CT Scans of the Brain: Gabapentin Overdose in Two Peritoneal Dialysis Patients

In parallel with the decline of renal excretory function, drug dosing of many drugs becomes more challenging. Finding the right dose is even more difficult if kidney replacement therapy is instituted. This is further aggravated by the fact that even for substances with a narrow therapeutic range, drug monitoring is only rarely offered, let alone advocated. This holds also true for gabapentin, an anticonvulsant drug that is increasingly prescribed for indications such as cancer-related pain, restless legs syndrome, migraine, or uremic pruritus. The drug is excreted unchanged in urine, so plasma clearance of gabapentin is directly proportional to creatinine clearance. Hence, renal impairment reduces gabapentin excretion and increases plasma gabapentin concentrations in a linear fashion. Therefore, the elimination half-life of gabapentin is between 5 and 9 h, in patients with normal renal function but increases to 132 h in patients on dialysis. Epidemiological data from the USRDS underline this problem. About 19% of the 140,899 adult USA patients enrolled in Medicare coverage received gabapentin in 2011. Its use was associated with an increased risk of altered mental status, fall, and fracture. We report 2 patients in which overdose of gabapentin occurred. In 1 patient, severe neurological symptoms prompted an extensive diagnostic work up, while the underlying cause of the clinical presentation was a supra-therapeutic drug level of gabapentin. Consequently, symptoms subsided with the discontinuation of the drug. Indication and drug dose of gabapentin in dialysis patients should be tightly controlled, and drug monitoring used to avoid unintended overdose.

Virtual Behavioral Health Treatment Satisfaction and Outcomes Across Time

PURPOSE

The COVID-19 pandemic continues to have major and long-lasting impacts on health care delivery and mental health. As health care shifted to telehealth, legislation was adjusted to expand telehealth allowances, creating a unique opportunity to elucidate outcomes. The aim of this study was to assess long-term patient and clinician satisfaction and outcomes with virtual behavioral health.

METHODS

Data were obtained over 16 months from surveys to patients and clinicians receiving/providing virtual treatment. Outcomes data also were collected from medical records of adults receiving in-person and virtual behavioral health treatment. Data were summarized using descriptive statistics. Groups were compared using various chi-squared tests for categorical variables, Likert response trends over time, and conditional independence, with Wilcoxon rank-sum or Jonckheere trend test used to assess continuous variables. P-values of ≤0.05 were considered statistically significant.

RESULTS

Patients gave high ratings to virtual treatment and indicated a preference for virtual formats. Both patient and clinician preference for virtual visits increased significantly with time, and many clinicians perceived virtual services to be equally effective to in-person. Virtual programs had higher completion rates, attendance rates, and number of treatment visits, suggesting that virtual behavioral health had equivalent or better outcomes to in-person treatment and that attitudes toward telehealth changed over time.

CONCLUSIONS

If trends found in this study continue, telehealth may emerge as a preferred option long term This is important considering the increase in mental health needs associated with the COVID-19 pandemic and the eventuality that in-person restrictions ease as the pandemic subsides.

A clinically relevant sheep model of orthotopic heart transplantation 24 h after donor brainstem death

Background

Heart transplantation (HTx) from brainstem dead (BSD) donors is the gold-standard therapy for severe/end-stage cardiac disease, but is limited by a global donor heart shortage. Consequently, innovative solutions to increase donor heart availability and utilisation are rapidly expanding. Clinically relevant preclinical models are essential for evaluating interventions for human translation, yet few exist that accurately mimic all key HTx components, incorporating injuries beginning in the donor, through to the recipient. To enable future assessment of novel perfusion technologies in our research program, we thus aimed to develop a clinically relevant sheep model of HTx following 24 h of donor BSD.

Methods

BSD donors (vs. sham neurological injury, 4/group) were hemodynamically supported and monitored for 24 h, followed by heart preservation with cold static storage. Bicaval orthotopic HTx was performed in matched recipients, who were weaned from cardiopulmonary bypass (CPB), and monitored for 6 h. Donor and recipient blood were assayed for inflammatory and cardiac injury markers, and cardiac function was assessed using echocardiography. Repeated measurements between the two different groups during the study observation period were assessed by mixed ANOVA for repeated measures.

Results

Brainstem death caused an immediate catecholaminergic hemodynamic response (mean arterial pressure, p = 0.09), systemic inflammation (IL-6 - p = 0.025, IL-8 - p = 0.002) and cardiac injury (cardiac troponin I, p = 0.048), requiring vasopressor support (vasopressor dependency index, VDI, p = 0.023), with normalisation of biomarkers and physiology over 24 h. All hearts were weaned from CPB and monitored for 6 h post-HTx, except one (sham) recipient that died 2 h post-HTx. Hemodynamic (VDI - p = 0.592, heart rate - p = 0.747) and metabolic (blood lactate, p = 0.546) parameters post-HTx were comparable between groups, despite the observed physiological perturbations that occurred during donor BSD. All p values denote interaction among groups and time in the ANOVA for repeated measures.

Conclusions

We have successfully developed an ovine HTx model following 24 h of donor BSD. After 6 h of critical care management post-HTx, there were no differences between groups, despite evident hemodynamic perturbations, systemic inflammation, and cardiac injury observed during donor BSD. This preclinical model provides a platform for critical assessment of injury development pre- and post-HTx, and novel therapeutic evaluation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00425-4.

1594 Invasive Ductal Carcinoma with Osteoclast Giant Cells During Pregnancy: A Case Report and A Review of Literature

Mammary carcinoma with Osteoclast Giant Cells (OGCs) is a rare tumour. Although several cases were reported, the significance of this histological finding remains incompletely understood. OGCs may occur in several types of breast carcinoma with different epidemiological characteristics but, in association with pregnancy, OGCs has not been reported to date. Here we report a case 37-year-old presenting with a symptomatic breast lump in pregnancy that has been confirmed clinically and radiologically. Microscopic examination of biopsies and surgical specimens showed OGCs accompanying invasive ductal carcinoma with no evidence of axillary metastasis. Immunohistochemical analysis revealed tumour cells to be positive for oestrogen, and progesterone receptors, with human epidermal growth factor negative status (ER6, PR8, HER2 negative).

This is the first case of OGCs during pregnancy to be reported, to our best of knowledge, following a search of the literature published in English language.

Comparative lung distribution of radiolabeled tobramycin between nebulized and intravenous administration in a mechanically-ventilated ovine model, an observational study

BACKGROUND

Ventilator-associated pneumonia is common and is treated using nebulized antibiotics. Although adequate pulmonary biodistribution is important for antibiotic effect, there is a lack of data for both intravenous (IV) and nebulized antibiotic administration during mechanical ventilation.

OBJECTIVE

To describe the comparative pulmonary regional distribution of IV and nebulized technetium-99m-labeled tobramycin (^99mTc-tobramycin) 400 mg in a mechanically-ventilated ovine model.

METHODS

The study was performed in a mechanically-ventilated ovine model. ^99mTc-tobramycin 400 mg was obtained using a radiolabeling process. Computed tomography (CT) was performed. Ten sheep were given ^99mTc-tobramycin 400 mg via either an IV (five sheep) or nebulized (five sheep) route. Planar images (dorsal, ventral, left lateral and right lateral) were obtained using a gamma camera. Blood samples were obtained every 15 min for 1 h (4 time points) and lung, liver, both kidney, and urine samples were obtained post-mortem.

RESULTS

Ten sheep were anesthetized and mechanically ventilated. Whole-lung deposition of nebulized ^99mTc-tobramycin 400 mg was significantly lower than with IV (8.8% vs. 57.1%, P<0.001). For both administration routes, there was significantly lower deposition in upper lung zones compared with the rest of the lungs. Dorsal deposition was significantly higher with nebulized ^99mTc-tobramycin 400 mg compared with IV (68.9% vs. 58.9%, P=0.003). Lung concentrations of ^99mTc-tobramycin were higher with IV compared with nebulized administration. There were significantly higher concentrations of ^99mTc-tobramycin in blood, liver and urine with IV administration compared with nebulized.

CONCLUSIONS

Nebulization resulted in lower whole and regional lung deposition of ^99mTc-tobramycin compared with IV administration and appeared to be associated with low blood and extra-pulmonary organ concentrations.

Talazoparib versus chemotherapy in patients with germline BRCA1/2-mutated HER2-negative advanced breast cancer: final overall survival results from the EMBRACA trial

BACKGROUND

In EMBRACA, talazoparib prolonged progression-free survival versus chemotherapy (hazard ratio [HR] 0.542 [95% confidence interval (CI) 0.413-0.711]; P < 0.0001) and improved patient-reported outcomes (PRO) in germline BRCA1/2 (gBRCA1/2)-mutated advanced breast cancer (ABC). We report final overall survival (OS).

PATIENTS AND METHODS

This randomized phase III trial enrolled patients with gBRCA1/2-mutated HER2-negative ABC. Patients received talazoparib or physician's choice of chemotherapy. OS was analyzed using stratified HR and log-rank test and prespecified rank-preserving structural failure time model to account for subsequent treatments.

RESULTS

A total of 431 patients were entered in a randomized study (287 talazoparib/144 chemotherapy) with 412 patients treated (286 talazoparib/126 chemotherapy). By 30 September 2019, 216 deaths (75.3%) occurred for talazoparib and 108 (75.0%) chemotherapy; median follow-up was 44.9 and 36.8 months, respectively. HR for OS with talazoparib versus chemotherapy was 0.848 (95% CI 0.670-1.073; P = 0.17); median (95% CI) 19.3 months (16.6-22.5 months) versus 19.5 months (17.4-22.4 months). Kaplan-Meier survival percentages (95% CI) for talazoparib versus chemotherapy: month 12, 71% (66% to 76%)/74% (66% to 81%); month 24, 42% (36% to 47%)/38% (30% to 47%); month 36, 27% (22% to 33%)/21% (14% to 29%). Most patients received subsequent treatments: for talazoparib and chemotherapy, 46.3%/41.7% received platinum and 4.5%/32.6% received a poly(ADP-ribose) polymerase (PARP) inhibitor, respectively. Adjusting for subsequent PARP and/or platinum use, HR for OS was 0.756 (95% bootstrap CI 0.503-1.029). Grade 3-4 adverse events occurred in 69.6% (talazoparib) and 64.3% (chemotherapy) patients, consistent with previous reports. Extended follow-up showed significant overall improvement and delay in time to definitive clinically meaningful deterioration in global health status/quality of life and breast symptoms favoring talazoparib versus chemotherapy (P < 0.01 for all), consistent with initial analyses.

CONCLUSIONS

In gBRCA1/2-mutated HER2-negative ABC, talazoparib did not significantly improve OS over chemotherapy; subsequent treatments may have impacted analysis. Safety was consistent with previous observations. PRO continued to favor talazoparib.

Racial and ethnic differences in patients involved in alcohol-impaired motor vehicle crashes and its related clinical outcomes among various age groups in the U.S

Objective(s): 1) to determine whether the proportion of alcohol-impaired patients involved in motor vehicle crashes (MVCs) varies by race/ethnicity within different age groups; 2) to explore the relationship between alcohol impairment, race/ethnicity and clinical outcomes among patients involved in MVCs across age groups.Methods: The 2012 National Trauma Data Bank (NTDB) queried for patients aged 16-55 involved in MVCs who received a blood ethanol test on admission.Results: Of the 44,216 patients involved in MVC, 68% were White, 14% Black, and 13% were Hispanic. About 36% were 16-25 years old, and 19% were 46-55 years old. Alcohol-impaired patients constituted 34% of the patients. The multiple logistic regression analysis of HLOS ≥ 2 days revealed that, when controlling for age, gender, race/ethnicity, insurance status, and the interaction between alcohol impairment and age as well as alcohol impairment and race/ethnicity, alcohol impairment positivity carried a 15% increase in probability of HLOS ≥ 2 days (OR 1.15, p < 0.0001). Additionally, using the 16-25 age group as reference, each of the older age groupings showed an increased probability of HLOS ≥ 2 days with ORs of 1.15, 1.32, and 1.51 for ages 26-35, 36-45, and 46-55, respectively (p-values < 0.0001). Blacks, Hispanics, and Asians/others were less likely than Whites to have HLOS ≥ 2 days with OR of 0.88, 0.89, and 0.88, respectively (p < 0.05). There was no statistically significant difference in the clinical outcome of mortality between races/ethnicities and alcohol-impaired driving.Conclusions: This study demonstrates that the proportions of alcohol-impaired driving and the associated clinical outcomes vary among race/ethnic groups in different age groups. More research is needed to determine the reasons for the observed differences in these vulnerable sub-groups.

Abstract P6-18-12: EMBRACA: Efficacy and safety of talazoparib or physician's choice of therapy in patients with advanced breast cancer and a germline BRCA1/2 mutation: A regional analysis

Background: Talazoparib (TAL) prevents DNA damage repair by inhibiting poly (ADP-ribose) polymerase (PARP) enzymes and trapping PARP on DNA, resulting in cell death in BRCA1/2-mutated cells.

Methods: EMBRACA is an open-label, randomized, 2-arm phase 3 trial in which efficacy and safety of TAL (1 mg/d) were compared with physician's choice of therapy (PCT; capecitabine, eribulin, gemcitabine, vinorelbine) in patients (pts) with locally advanced or metastatic breast cancer (ABC) and a germline BRCA mutation (gBRCAm). Outcomes were assessed by region of the world (North America [NA]; Europe [EU]; rest of world [ROW]). Progression-free survival (PFS), objective response rate (ORR), and clinical benefit rate (CBR) at 24 wks were assessed; safety was also assessed.

Results: 431 pts were randomized 2:1. Pt characteristics were well balanced, although a higher percentage of pts in ROW had more severe disease (eg, triple-negative breast cancer [TNBC], Disease-free interval [DFI]&lt;12 mo, more distant metastases, more disease sites) and were on average younger than pts in NA/EU. TAL provided improvement in PFS, ORR, and CBR in all regions vs PCT. The most common toxicities with TAL included anemia, neutropenia, thrombocytopenia, fatigue, and nausea for all regions. Alopecia was less frequent with TAL in EU/ROW. Serious adverse events for pts receiving TAL were more frequent in EU than NA/ROW. Incidences of adverse events associated with permanent treatment discontinuation in pts receiving TAL were low in all regions and generally lower than for PCT.

Table 1CategoryNA* (N=156)EU* (N=190)ROW* (N=85)Mean age, years49.049.244.2Race, %   White76.971.152.9Black5.8-3.5Asian5.8-42.4Not reported-27.4-TNBC, %424447BRCA1**, %414748BRCA2**, %595352DFI&lt;12 mo, %313444Distant metastases, %949397≥3 disease sites, %474049PFS, (hazard ratio [HR]; [95% CI]); P value0.46 [0.29-0.74] P=.00090.52 [0.33-0.80]; P&lt;.0030.57 [0.31-1.07] ;P=.08ORR (odds ratio [OR] [95% CI]); P value5.54 [2.4-16.1];P&lt;.00013.75 [1.57-9.87]; P=.0016.7 [1.61-28.39]; P=.001CBR (OR [95% CI]); P value4.71 [2.20-10.57]; P&lt;.00013.39 [1.56-7.36]; P=.00075.70 [1.70-17.13]; P=.002Hematologic AEs, %   Anemia50.558.642.6Neutropenia31.332.346.3Thrombocytopenia28.322.635.2Nonhematologic AEs, %   Fatigue59.643.650.0Nausea47.545.957.4Headache32.330.837.0Alopecia34.320.320.4Serious adverse events, %25.340.622.2Treatment discontinuation, n/N, (%)   TAL7/99 (7.1)12/133 (9.0)3/54 (5.6)PCT7/43 (16.3)3/54 (5.6)2/29 (6.9)AE, adverse event; CI, confidence interval; *NA (United States); EU (Belgium, France, Germany, Ireland, Italy, Poland, Spain, United Kingdom, Russia, Ukraine, Israel); ROW (Brazil, Korea, Australia, Taiwan).**Central laboratory.

Conclusions: In pts with gBRCAm ABC, TAL demonstrated significant improvements in clinical outcomes compared with PCT regardless of the region of the world in which they lived. However, slight differences among the regions in baseline characteristics were noted, possibly due to regional variation in diagnosis and detection of gBRCAm ABC as well as different treatment paradigms for metastatic breast cancer.

Funding: Medivation LLC, acquired by Pfizer.

Citation Format: Mina L, Lee K-H, Gonçalves A, Woodward N, Hurvitz SA, Diab S, Yerushalmi R, Goodwin A, Moreira Costa Zorzetto M, Kim S-B, Czibere A, Tudor IC, Gauthier E, Litton JK, Ettl J. EMBRACA: Efficacy and safety of talazoparib or physician's choice of therapy in patients with advanced breast cancer and a germline BRCA1/2 mutation: A regional analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-12.

The effects of normovolemic anemia and blood transfusion on cerebral microcirculation after severe head injury

BACKGROUND

Cerebral regional microcirculation is altered following severe head injury. In addition to tissue disruption, partial pressure of tissue oxygenation is impaired due to an increase in the oxygen tissue gradient. The heterogenic distribution of cerebral microcirculation is multifactorial, and acute anemia challenges further the delivery of oxygen to tissues. Currently, a restrictive transfusion threshold is globally applied; however, it is unclear how anemia modifies regional cerebral microcirculation; hence, it is unclear if by aiming to a global endpoint, specific anatomical regions undergo ischemia. This study aims to quantify the temporal changes in cerebral microcirculation after severe head injury, under the effect of anemia and transfusion. It also aims to assess its effects specifically at the ischemic penumbra compared to contralateral regions and its interactions with axonal integrity in real time. Twelve ovine models were subjected to a severe contusion and acceleration-deceleration injury. Normovolemic anemia to a restrictive threshold was maintained after injury, followed by autologous transfusion. Direct quantification of cerebral microcirculation used cytometric count of color-coded microspheres. Axonal injury was assessed using amyloid precursor protein staining.

RESULTS

A mixed-effect regression model from pre-transfusion to post-transfusion times with a random intercept for each sheep was used. Cerebral microcirculation amongst subjects with normal intracranial pressure was maintained from baseline and increased further after transfusion. Subjects with high intracranial pressure had a consistent reduction of their microcirculation to ischemic thresholds (20-30 ml/100 g/min) without an improvement after transfusion. Cerebral PtiO₂ was reduced when exposed to anemia but increased in a 9.6-fold with transfusion 95% CI 5.6 to 13.6 (p value < 0.001).

CONCLUSIONS

After severe head injury, the exposure to normovolemic anemia to a restrictive transfusion threshold, leads to a consistent reduction on cerebral microcirculation below ischemic thresholds, independent of cerebral perfusion pressure. Amongst subjects with raised intracranial pressure, microcirculation does not improve after transfusion. Cerebral oxymetry is impaired during anemia with a statistically significant increase after transfusion. Current transfusion practices in neurocritical care are based on a rigid hemoglobin threshold, a view that excludes cerebral metabolic demands and specific needs. An RCT exploring these concepts is warranted.

A research pathway for the study of the delivery and disposition of nebulised antibiotics: an incremental approach from in vitro to large animal models

Background

Nebulised antibiotics are frequently used for the prevention or treatment of ventilator-associated pneumonia. Many factors may influence pulmonary drug concentrations with inaccurate dosing schedules potentially leading to therapeutic failure and/or the emergence of antibiotic resistance. We describe a research pathway for studying the pharmacokinetics of a nebulised antibiotic during mechanical ventilation using in vitro methods and ovine models, using tobramycin as the study antibiotic.

Methods

In vitro studies using a laser diffractometer and a bacterial-viral filter were used to measure the effect of the type and size of tracheal tubes and antibiotic concentration on the particle size distribution of the tobramycin 400 mg (4 ml; 100 mg/ml) and 160 mg (4 ml, 40 mg/ml) aerosol and nebulised mass delivered. To compare the regional drug distribution in the lung of two routes (intravenous and nebulised) of drug administration of tobramycin 400 mg, technetium-99m-labelled tobramycin 400 mg with planar nuclear medicine imaging was used in a mechanically ventilated ovine model. To measure tobramycin concentrations by intravenous and nebulised tobramycin 400 mg (4 ml, 100 mg/ml) administration in the lung interstitial space (ISF) fluid and blood of mechanically ventilated sheep, the microdialysis technique was used over an 8-h duration.

Results

Tobramycin 100 mg/ml achieved a higher lung dose (121.3 mg) compared to 40 mg/ml (41.3 mg) solution. The imaging study with labelled tobramycin indicated that nebulised tobramycin distributed more extensively into each lung zone of the mechanically ventilated sheep than intravenous administration. A higher lung ISF peak concentration of tobramycin was observed with nebulised tobramycin (40.8 mg/l) compared to intravenous route (19.0 mg/l).

Conclusions

The research methods appear promising to describe lung pharmacokinetics for formulations intended for nebulisation during mechanical ventilation. These methods need further validation in an experimental pneumonia model to be able to contribute toward optimising dosing regimens to inform clinical trials and/or clinical use.

Cerebral Microcirculation and Histological Mapping After Severe Head Injury: A Contusion and Acceleration Experimental Model

Background

Cerebral microcirculation after severe head injury is heterogeneous and temporally variable. Microcirculation is dependent upon the severity of injury, and it is unclear how histology relates to cerebral regional blood flow.

Objective

This study assesses the changes of cerebral microcirculation blood flow over time after an experimental brain injury model in sheep and contrasts these findings with the histological analysis of the same regions with the aim of mapping cerebral flow and tissue changes after injury.

Methods

Microcirculation was quantified using flow cytometry of color microspheres injected under intracardiac ultrasound to ensure systemic and homogeneous distribution. Histological analysis used amyloid precursor protein staining as a marker of axonal injury. A mapping of microcirculation and axonal staining was performed using adjacent layers of tissue from the same anatomical area, allowing flow and tissue data to be available from the same anatomical region. A mixed effect regression model assessed microcirculation during 4 h after injury, and those results were then contrasted to the amyloid staining qualitative score.

Results

Microcirculation values for each subject and tissue region over time, including baseline, ranged between 20 and 80 ml/100 g/min with means that did not differ statistically from baseline flows. However, microcirculation values for each subject and tissue region were reduced from baseline, although their confidence intervals crossing the horizontal ratio of 1 indicated that such reduction was not statistically significant. Histological analysis demonstrated the presence of moderate and severe score on the amyloid staining throughout both hemispheres.

Conclusion

Microcirculation at the ipsilateral and contralateral site of a contusion and the ipsilateral thalamus and medulla showed a consistent decline over time. Our data suggest that after severe head injury, microcirculation in predefined areas of the brain is reduced from baseline with amyloid staining in those areas reflecting the early establishment of axonal injury.

Multifocal discrete osteolysis in a horse with silicate associated osteoporosis

Silicate associated osteoporosis (SAO) was diagnosed post mortem in an adult horse with the shortest documented exposure to cytotoxic silicates of 2 years. The horse was evaluated for a 6-months history of progressive back tenderness and acute onset of lameness. The horse had a marked (4/5) [American Association of Equine Practitioners scale] left forelimb lameness, moderate (2/5) hindlimb ataxia and weakness, and cervical pain upon palpation. Physical examination did not reveal clinical skeletal deformities or respiratory compromise. Radiographs revealed widespread, discrete, sharply delineated, osteolytic lesions in the skull, vertebral column, ribs, scapulae and middle phalanx (P2) of the left forelimb and a diffuse bronchointerstitial lung pattern. The presumptive clinical diagnosis was widespread, metastatic osteolytic neoplasia. Due to the poor quality of life and grave prognosis, the horse was humanely euthanised. Post mortem examination revealed pulmonary silicosis in the lungs and hilar lymph nodes and osteolytic lesions with numerous, large osteoclasts and disorganised bone remodeling both consistent with SAO. SAO should be included as a differential diagnosis for horses with widespread, multifocal, discrete osteolysis and history of exposure to endemic regions with possible cytotoxic silicate inhalation. Exposure time of 2 years is potentially sufficient to develop SAO.

Abstract PD3-14: Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer

Background

LIV-1, a transmembrane protein and downstream target of STAT3, is highly expressed in breast cancer cells. It is associated with lymph node involvement and metastatic progression. SGN-LIV1A is an anti-LIV-1 antibody conjugated via a protease-cleavable linker to monomethyl auristatin E (MMAE). Upon binding to cell-surface LIV-1, SGN-LIV1A is internalized and releases MMAE, which disrupts microtubulin and induces apoptosis.

Methods

This ongoing, phase 1 study evaluates safety, tolerability, pharmacokinetics, and antitumor activity of SGN-LIV1A (q3wks IV) in women with LIV-1-positive, unresectable, locally advanced or metastatic breast cancer (LA/MBC) (NCT01969643). Patients (pts) with measurable disease and ≥2 prior cytotoxic regimens for LA/MBC are eligible. Pts with ≥ Grade 2 neuropathy are excluded. Response is assessed per RECIST v1.1; pts with stable disease (SD) or better can continue treatment until disease progression or intolerable toxicity. At completion of dose escalation in hormone receptor-positive/HER2-negative (HR+/HER2–) and triple-negative (TN) pts, expansion cohorts were opened to further evaluate safety and antitumor activity of monotherapy in TN pts. Tumor biopsies are evaluated for LIV-1 expression.

Results

To date, 69 pts (18 HR+/HER2–, 51 TN) have received a median of 3 cycles (range, 1–12) of SGN-LIV1A at doses of 0.5–2.8 mg/kg. Median age was 56 yrs. Pts had a median of 3 prior cytotoxic regimens for LA/MBC; 58 had visceral disease and 37 had bone metastases. No dose-limiting toxicities (DLTs) occurred in 19 DLT-evaluable pts; maximum tolerated dose was not exceeded at 2.8 mg/kg. Expansion cohorts of TN pts were opened at 2.0 and 2.5 mg/kg. Treatment-emergent adverse events (AEs) reported in ≥25% of pts were fatigue (59%), nausea (51%), peripheral neuropathy (44%), alopecia (36%), decreased appetite (33%), constipation (30%), abdominal pain, diarrhea, and neutropenia (25% each). Most AEs were Grade 1/2; AEs ≥ Grade 3 included neutropenia (25%) and anemia (15%). Febrile neutropenia occurred in 2 pts whose total dose exceeded 200 mg per cycle, including 1 treatment-related death due to sepsis. No other treatment-related deaths occurred on-study. Seven pts discontinued treatment due to AEs. In dose escalation, activity was observed in 17 efficacy evaluable (EE) HR+/HER2- pts, with a disease control rate (DCR= CR+PR+SD) of 59% (10 SD), including 1 pt with SD ≥24 wks. Among the 44 EE TN pts (dose escalation plus expansion cohorts), the objective response rate (ORR) was 32% (14 PR) with a confirmed PR rate of 21%, DCR was 64% (14 PR, 14 SD), and clinical benefit rate (CBR=CR+PR+SD ≥24 wks) was 36% (16 pts). For TN pts, median PFS was 11.3 wks (95% CI: 6.1, 17.1); 10 pts remain on treatment.

Of 631 MBC tumor samples of all clinical subtypes evaluated for LIV-1, 91% were positive; 75% had moderate-to-high expression (H-score ≥100).

Conclusions

LIV-1 is expressed in almost all MBC tumors. SGN-LIV1A monotherapy was generally well tolerated and showed encouraging antitumor activity in heavily pretreated TN MBC, with a PR rate of 32%, confirmed PR rate of 21%, and CBR (≥24 wks) of 36%. Response duration data continue to evolve. Enrollment continues in the TN monotherapy expansion cohort.

Citation Format: Modi S, Pusztai L, Forero A, Mita M, Miller KD, Weise A, Krop I, Burris III H, Kalinsky K, Tsai M, Liu MC, Hurvitz SA, Wilks S, Ademuyiwa F, Diab S, Han HS, Kato G, Nanda R, O'Shaughnessy J, Kostic A, Li M, Specht J. Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD3-14.

An Ovine Model of Hyperdynamic Endotoxemia and Vital Organ Metabolism

BACKGROUND

Animal models of endotoxemia are frequently used to understand the pathophysiology of sepsis and test new therapies. However, important differences exist between commonly used experimental models of endotoxemia and clinical sepsis. Animal models of endotoxemia frequently produce hypodynamic shock in contrast to clinical hyperdynamic shock. This difference may exaggerate the importance of hypoperfusion as a causative factor in organ dysfunction. This study sought to develop an ovine model of hyperdynamic endotoxemia and assess if there is evidence of impaired oxidative metabolism in the vital organs.

METHODS

Eight sheep had microdialysis catheters implanted into the brain, heart, liver, kidney, and arterial circulation. Shock was induced with a 4 h escalating dose infusion of endotoxin. After 3 h vasopressor support was initiated with noradrenaline and vasopressin. Animals were monitored for 12 h after endotoxemia. Blood samples were recovered for hemoglobin, white blood cell count, creatinine, and proinflammatory cytokines (IL-1Beta, IL-6, and IL-8).

RESULTS

The endotoxin infusion was successful in producing distributive shock with the mean arterial pressure decreasing from 84.5 ± 12.8 mm Hg to 49 ± 8.03 mm Hg (P < 0.001). Cardiac index remained within the normal range decreasing from 3.33 ± 0.56 L/min/m to 2.89l ± 0.36 L/min/m (P = 0.0845). Lactate/pyruvate ratios were not significantly abnormal in the heart, brain, kidney, or arterial circulation. Liver microdialysis samples demonstrated persistently high lactate/pyruvate ratios (mean 37.9 ± 3.3).

CONCLUSIONS

An escalating dose endotoxin infusion was successful in producing hyperdynamic shock. There was evidence of impaired oxidative metabolism in the liver suggesting impaired splanchnic perfusion. This may be a modifiable factor in the progression to multiple organ dysfunction and death.

Expression of ERG Protein and TMRPSS2-ERG Fusion in Prostatic Carcinoma in Egyptian Patients

AIM

Prostate cancer (PCa) is the second most common cancers in men worldwide. Its incidence can be influenced by several risk factors including genetic susceptibility. Therefore the search for the expression of a certain gene (ERG) and its rearrangement could give us clues for proper identification of PCa. And the study of ERG expression and its comparison to FISH in Egyptian patients can show whether ERG immunophenotype could be used instead of FISH, as it is cheaper.

MATERIALS AND METHODS

This study was performed on 85 cases of PCa, showing 30 cases with HGPIN and 30 cases of prostatic hyperplasia. All were immunohistochemistry stained using ERG monoclonal rabbit antihuman antibody was used (clone: EP111). FISH analysis was performed in 38 biopsies of PCa cases to detect TMRPSS2-ERG rearrangement using the FISH ZytoLight TriCheck Probe (SPEC TMRPSS2-ERG).

RESULTS

ERG expression was found in 26% of PCa cases and 20% of HGPIN cases. FISH analysis showed fusion of 21 cases of PCa (out of 22 cases showing ERG immunoexpression).

CONCLUSION

Our findings emphasise that only malignant and pre-malignant cells and not benign cells from the prostate stain positive. ERG expression may offer a simpler, accurate and less costly alternative for evaluation of ERG fusion status in PCa.

Abstract P4-22-04: A randomized, double-blind, phase 2 study of ruxolitinib (RUX) or placebo (PBO) in combination with capecitabine (CAPE) in patients (pts) with advanced HER2-negative breast cancer (ABC) and elevated C-reactive protein (CRP), a marker of systemic inflammation

Background: Systemic inflammation is associated with poor prognosis in pts with ABC. The JAK/STAT pathway is a key regulator of inflammatory signaling, associated with tumorigenesis, cell survival, and progression. We evaluated the efficacy and safety of RUX, a JAK1/JAK2 inhibitor, plus CAPE in pts with HER2-negative ABC and high systemic inflammation defined by the modified Glasgow Prognostic Score (mGPS). Methods: In this double-blind phase 2 trial, pts were randomized 1:1 to 21 day cycles of RUX+CAPE or PBO+CAPE: RUX 15 mg or PBO PO BID for 21 d; CAPE 1000 mg/m2 PO BID for 14 d. Key inclusion criteria were systemic inflammation by mGPS of 1 or 2 (ie, CRP &gt;10 mg/L), ECOG performance status ≤2, ≤2 prior chemotherapy regimens, and no prior CAPE. The primary endpoint was overall survival (OS); key secondary endpoints were progression-free survival (PFS), objective response rate (ORR; complete [CR] + partial response [PR]) per RECIST v1.1, clinical benefit rate (CBR; CR + PR + stable disease for ≥6 mo), duration of response, and safety. Treatment differences in OS and PFS were analyzed by the log-rank test; HRs and CIs were analyzed by the Cox proportional hazards model. Results: Baseline characteristics were similar between pts randomized to RUX+CAPE (n=76) vs PBO+CAPE (n=73): mGPS status (1, 82.9% vs 83.6%), hormone receptor (HR) status (positive, 67.1% vs 63.0%), and number of prior chemotherapy regimens for ABC (0, 50.0% vs 50.7%; 1, 38.2% vs 34.2%; 2, 9.2% vs 13.7%). Median treatment durations were 85 d with RUX in the RUX+CAPE group and 65 d with PBO in the PBO+CAPE group. Median OS was 11.2 mo with RUX+CAPE vs 10.9 mo with PBO+CAPE (HR, 0.932; 95% CI, 0.59–1.46; P=0.762). Median OS was 6.1 mo with RUX+CAPE vs 5.5 mo with PBO+CAPE in HR-negative pts and 11.7 mo and 12.2 mo in HR-positive pts. Median PFS was 4.5 mo with RUX+CAPE and 2.5 mo with PBO+CAPE (HR, 0.737; 95% CI, 0.49–1.12; P=0.151). Median PFS was 2.1 mo with RUX+CAPE vs 2.2 mo with PBO+CAPE in HR-negative pts and 6.1 mo and 4.1 mo in HR-positive pts. ORRs were 28.9% and 13.7% (P=0.024) in the RUX+CAPE and PBO+CAPE arms, respectively. The CBRs were 13.2% and 6.8%, respectively (P=0.278). Worsening of hematologic toxicity was higher and rates of grade 3/4 palmar-plantar erythrodysethesia (PPE) were lower (1.4% vs 12.7%, respectively) with RUX+CAPE (Table).

Safety RUX+CAPE (n=71)PBO+CAPE (n=71)%All-GradeGrade 3/4All-GradeGrade 3/4Nonhematologic Adverse Event*Fatigue56.35.643.74.2Nausea54.98.549.35.6Diarrhea47.98.526.82.8PPE46.51.438.012.7Vomiting38.05.629.64.2Hypokalemia15.58.57.02.8Worsening of Hematologic Toxicity†Anemia80.323.956.37.0Lymphopenia40.815.545.112.7Neutropenia39.411.322.52.8Thrombocytopenia39.411.315.51.4*Most common all-grade (≥35%) or grade 3/4 (≥5%) events in the RUX+CAPE arm (safety group). †Laboratory abnormalities.

Conclusion: These data support the prognostic capabilities of the mGPS. The addition of RUX to CAPE for pts with ABC and high systemic inflammation was associated with an improved ORR compared with PBO+CAPE, but did not improve OS or PFS.

Citation Format: O'Shaughnessy J, DeMichele A, Ma C, Richards P, Yardley DA, Wright G, Kalinsky K, Steis R, Diab S, Kennealey G, Geschwindt R, Jiang W, Rugo H. A randomized, double-blind, phase 2 study of ruxolitinib (RUX) or placebo (PBO) in combination with capecitabine (CAPE) in patients (pts) with advanced HER2-negative breast cancer (ABC) and elevated C-reactive protein (CRP), a marker of systemic inflammation [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-04.

Quantification of perflutren microsphere contrast destruction during transit through an ex vivo extracorporeal membrane oxygenation circuit

BACKGROUND

Echocardiography is a key investigation in the management of patients on extracorporeal membrane oxygenation (ECMO). However, echocardiographic images are often non-diagnostic in this patient population. Contrast-enhanced echocardiography may overcome many of these limitations but contrast microspheres are hydrodynamically labile structures prone to destruction from shear forces and turbulent flow, which may exist within an ECMO circuit. This study sought to evaluate microsphere destruction (utilising signal intensity as a marker of contrast concentration) during transit through an ECMO circuit.

METHODS

Activated Definity® contrast was diluted to 50 ml with normal saline and infused into a crystalloid primed ex vivo ECMO with a Quadrox oxygenator at 150 ml/h. Imaging was performed on pre- and post-pump head/oxygenator sections of the circuit using a Philips iE33 scanner and S5-1 transducer. Five-millimetre regions of interest were placed in the centre of the ultrasound field. Average signal intensity (decibels) was calculated at speeds of 1000, 2000, 3000 and 4000 rpm and then repeated with an infusion rate of 300 ml/h. The oxygenator was then spliced out of the circuit and the measures repeated.

RESULTS

There was a significant reduction in contrast concentration during passage through the ECMO circuit at all speeds (with higher pump head speeds resulting in greater microsphere destruction). In a circuit with an oxygenator, relative decrease in signal intensity was 21.4 versus 5.2 % without an oxygenator. There was significant destruction of contrast microspheres during passage through the ECMO circuit at all pump head speeds. An oxygenator contributed to microsphere destruction at a significantly greater level than the pump head alone. There was no significant difference in mean signal intensity reduction in the circuit between an infusion of 150 or 300 ml/h (3.5 ± 3.2 versus 3.6 ± 2.5 dB, respectively, p = 0.79).

CONCLUSIONS

Flow of contrast through an ECMO circuit results in significant destruction of microspheres. Circuits with an oxygenator result in significantly greater levels of contrast destruction than by the pump head alone. Clinicians should be cognisant of the relationship between ECMO circuit configurations, pump head speed and contrast destruction when performing a contrast-enhanced echocardiogram in patients supported with ECMO.

Cerebral microcirculation during mild head injury after a contusion and acceleration experimental model in sheep

BACKGROUND

Cerebral microcirculation after head injury is heterogeneous and temporally variable. Regions at risk of infarction such as peri-contusional areas are vulnerable to anaemia. However, direct quantification of the cerebral microcirculation is clinically not feasible. This study describes a novel experimental head injury model correlating cerebral microcirculation with histopathology analysis.

OBJECTIVE

To test the hypothesis that cerebral microcirculation at the ischaemic penumbrae is reduced over time when compared with non-injured regions.

METHODS

Merino sheep were instrumented using a transeptal catheter to inject coded microspheres into the left cardiac atrium, ensuring systemic distribution. After a blunt impact over the left parietal region, cytometric analyses quantified cerebral microcirculation and amyloid precursor protein staining identified axonal injury in pre-defined anatomical regions. A mixed effect regression model assessed the hourly blood flow results during 4 hours after injury.

RESULTS

Cerebral microcirculation showed temporal reductions with minimal amyloid staining except for the ipsilateral thalamus and medulla.

CONCLUSION

The spatial heterogeneity and temporal reduction of cerebral microcirculation in ovine models occur early, even after mild head injury, independent of the intracranial pressure and the level of haemoglobin. Alternate approaches to ensure recovery of regions with reversible injury require a targeted assessment of cerebral microcirculation.

West Nile Virus Infection in Sheep

West Nile virus (WNV) infection has been detected in many species of birds and mammals, but scant information is available about the disease in small ruminants. West Nile virus was diagnosed in 6 sheep with neurological signs and encephalitis, in California between 2002 and 2014. All sheep had severe lymphoplasmacytic meningoencephalitis. Lymphoplasmacytic myelitis was also detected in 2 sheep where the spinal cord was examined. Brain tissue was positive for WNV detected by polymerase chain reaction in 6 of 6 sheep and by immunohistochemistry (IHC) in 5 of 6 sheep. Viral antigen was not detected by IHC in extraneural tissues in the 3 sheep examined. West Nile virus RNA was sequenced from 2 of 6 sheep, and each one clusters closely with WNV isolated from mosquito pools from nearby locations at similar times. West Nile virus was the most common cause of viral encephalitis in sheep diagnosed at this laboratory between 2002 and 2014, accounting for 6 of 9 sheep.

Abstract P1-09-02: Higher incidence of second cancers in African American (AA) patients compared to Caucasian patients with a primary breast cancer

Background: AA women with breast cancer have lower survival rates compared to Caucasian women. Since this lower survival rate may be related to genetic mutations, and environmental/socioeconomically factors, we hypothesize that the same factors may lead to a higher risk of secondary cancers after an initial diagnosis of breast cancer.

Method: Analysis of the Surveillance, Epidemiology, and End Results (SEER) Program data using Multiple Primary - Standardized Incidence Ratio parameters. The incidence of second cancer diagnoses in AA and Caucasian women previously diagnosed with breast was compared to the incidence of cancer in the general population matched by age, race, and year of diagnosis. Results are reported as the observed risk divided by the expected risk (O/E).

Results: For the 43,688 AA pts, the overall O/E and excess risks were 1.48 and 51.2 compared to 1.11 and 14.7 for the 428,103 Caucasian patients. The mean ages of diagnoses of initial breast cancer diagnosis and second cancer were 57.2 and 65 years for AA patients compared to 61.8 and 70.2 years for Caucasian patients. The following is a summary of statically significant (p &lt;0.05) selected O/E by the site of second cancer :

O/E for AA and white by site of second cancerSiteAAWhiteOral Cavity and Pharynx1.651.41Digestive System1.181Respiratory System1.271.13Skin excluding Basal and Squamous1.931.33Breast1.671.18Female Genital System1.110.95Urinary System1.561.18Endocrine System1.521.38All Lymphatic and Hematopoietic Diseases1.261.05

This higher risk of second cancers occurred despite the lower relative survival rate for AA compared to Caucasian patients with a 5-year relative survival rate of 68.6% for AA and 78.3% for Caucasian patients.

Conclusions: To our knowledge, this is the first report of the incidence of second cancers in AA patients with breast cancer compared to caucasian. More research to understand the biological, genetic, therapeutic, and environmental factors leading to this higher risk of second cancers is warranted.

Citation Format: Diab N, Clark G, Hamlington B, Brzeskiewicz L, Langer L, Diab S. Higher incidence of second cancers in African American (AA) patients compared to Caucasian patients with a primary breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-09-02.

Cerebral Microcirculation during Experimental Normovolaemic Anemia

Anemia is accepted among critically ill patients as an alternative to elective blood transfusion. This practice has been extrapolated to head injury patients with only one study comparing the effects of mild anemia on neurological outcome. There are no studies quantifying microcirculation during anemia. Experimental studies suggest that anemia leads to cerebral hypoxia and increased rates of infarction, but the lack of clinical equipoise, when testing the cerebral effects of transfusion among critically injured patients, supports the need of experimental studies. The aim of this study was to quantify cerebral microcirculation and the potential presence of axonal damage in an experimental model exposed to normovolaemic anemia, with the intention of describing possible limitations within management practices in critically ill patients. Under non-recovered anesthesia, six Merino sheep were instrumented using an intracardiac transeptal catheter to inject coded microspheres into the left atrium to ensure systemic and non-chaotic distribution. Cytometric analyses quantified cerebral microcirculation at specific regions of the brain. Amyloid precursor protein staining was used as an indicator of axonal damage. Animals were exposed to normovolaemic anemia by blood extractions from the indwelling arterial catheter with simultaneous fluid replacement through a venous central catheter. Simultaneous data recording from cerebral tissue oxygenation, intracranial pressure, and cardiac output was monitored. A regression model was used to examine the effects of anemia on microcirculation with a mixed model to control for repeated measures. Homogeneous and normal cerebral microcirculation with no evidence of axonal damage was present in all cerebral regions, with no temporal variability, concluding that acute normovolaemic anemia does not result in short-term effects on cerebral microcirculation in the ovine brain.

In Vivo Evaluation of Active and Passive Physiological Control Systems for Rotary Left and Right Ventricular Assist Devices

Preventing ventricular suction and venous congestion through balancing flow rates and circulatory volumes with dual rotary ventricular assist devices (VADs) configured for biventricular support is clinically challenging due to their low preload and high afterload sensitivities relative to the natural heart. This study presents the in vivo evaluation of several physiological control systems, which aim to prevent ventricular suction and venous congestion. The control systems included a sensor-based, master/slave (MS) controller that altered left and right VAD speed based on pressure and flow; a sensor-less compliant inflow cannula (IC), which altered inlet resistance and, therefore, pump flow based on preload; a sensor-less compliant outflow cannula (OC) on the right VAD, which altered outlet resistance and thus pump flow based on afterload; and a combined controller, which incorporated the MS controller, compliant IC, and compliant OC. Each control system was evaluated in vivo under step increases in systemic (SVR ∼1400-2400 dyne/s/cm(5) ) and pulmonary (PVR ∼200-1000 dyne/s/cm(5) ) vascular resistances in four sheep supported by dual rotary VADs in a biventricular assist configuration. Constant speed support was also evaluated for comparison and resulted in suction events during all resistance increases and pulmonary congestion during SVR increases. The MS controller reduced suction events and prevented congestion through an initial sharp reduction in pump flow followed by a gradual return to baseline (5.0 L/min). The compliant IC prevented suction events; however, reduced pump flows and pulmonary congestion were noted during the SVR increase. The compliant OC maintained pump flow close to baseline (5.0 L/min) and prevented suction and congestion during PVR increases. The combined controller responded similarly to the MS controller to prevent suction and congestion events in all cases while providing a backup system in the event of single controller failure.

Novel 24-h ovine model of brain death to study the profile of the endothelin axis during cardiopulmonary injury

BACKGROUND

Upregulation of the endothelin axis has been observed in pulmonary tissue after brain death, contributing to primary graft dysfunction and ischaemia reperfusion injury. The current study aimed to develop a novel, 24-h, clinically relevant, ovine model of brain death to investigate the profile of the endothelin axis during brain death-associated cardiopulmonary injury. We hypothesised that brain death in sheep would also result in demonstrable injury to other transplantable organs.

METHODS

Twelve merino cross ewes were randomised into two groups. Following induction of general anaesthesia and placement of invasive monitoring, brain death was induced in six animals by inflation of an extradural catheter. All animals were supported in an intensive care unit environment for 24 h. Animal management reflected current human donor management, including administration of vasopressors, inotropes and hormone resuscitation therapy. Activation of the endothelin axis and transplantable organ injury were assessed using ELISA, immunohistochemistry and standard biochemical markers.

RESULTS

All animals were successfully supported for 24 h. ELISA suggested early endothelin-1 and big endothelin-1 release, peaking 1 and 6 h after BD, respectively, but there was no difference at 24 h. Immunohistochemistry confirmed the presence of the endothelin axis in pulmonary tissue. Brain dead animals demonstrated tachycardia and hypertension, followed by haemodynamic collapse, typified by a reduction in systemic vascular resistance to 46 ± 1 % of baseline. Mean pulmonary artery pressure rose to 186 ± 20 % of baseline at induction and remained elevated throughout the protocol, reaching 25 ± 2.2 mmHg at 24 h. Right ventricular stroke work increased 25.9 % above baseline by 24 h. Systemic markers of cardiac and hepatocellular injury were significantly elevated, with no evidence of renal dysfunction.

CONCLUSIONS

This novel, clinically relevant, ovine model of brain death demonstrated that increased pulmonary artery pressures are observed after brain death. This may contribute to right ventricular dysfunction and pulmonary injury. The development of this model will allow for further investigation of therapeutic strategies to minimise the deleterious effects of brain death on potentially transplantable organs.

Necrotizing Enteritis and Hyperammonemic Encephalopathy Associated With Equine Coronavirus Infection in Equids

Equine coronavirus (ECoV) is a Betacoronavirus recently associated clinically and epidemiologically with emerging outbreaks of pyrogenic, enteric, and/or neurologic disease in horses in the United States, Japan, and Europe. We describe the pathologic, immunohistochemical, ultrastructural, and molecular findings in 2 horses and 1 donkey that succumbed to natural infection with ECoV. One horse and the donkey (case Nos. 1, 3) had severe diffuse necrotizing enteritis with marked villous attenuation, epithelial cell necrosis at the tips of the villi, neutrophilic and fibrinous extravasation into the small intestinal lumen (pseudomembrane formation), as well as crypt necrosis, microthrombosis, and hemorrhage. The other horse (case No. 2) had hyperammonemic encephalopathy with Alzheimer type II astrocytosis throughout the cerebral cortex. ECoV was detected by quantitative polymerase chain reaction in small intestinal tissue, contents, and/or feces, and coronavirus antigen was detected by immunohistochemistry in the small intestine in all cases. Coronavirus-like particles characterized by spherical, moderately electron lucent, enveloped virions with distinct peplomer-like structures projecting from the surface were detected by negatively stained transmission electron microscopy in small intestine in case No. 1, and transmission electron microscopy of fixed small intestinal tissue from the same case revealed similar 85- to 100-nm intracytoplasmic particles located in vacuoles and free in the cytoplasm of unidentified (presumably epithelial) cells. Sequence comparison showed 97.9% to 99.0% sequence identity with the ECoV-NC99 and Tokachi09 strains. All together, these results indicate that ECoV is associated with necrotizing enteritis and hyperammonemic encephalopathy in equids.

Feasibility of perflutren microsphere contrast transthoracic echocardiography in the visualization of ventricular endocardium during venovenous extracorporeal membrane oxygenation in a validated ovine model

BACKGROUND

Transthoracic echocardiography (TTE) during extra corporeal membrane oxygenation (ECMO) is important but can be technically challenging. Contrast-specific TTE can improve imaging in suboptimal studies. These contrast microspheres are hydrodynamically labile structures. This study assessed the feasibility of contrast echocardiography (CE) during venovenous (VV) ECMO in a validated ovine model.

METHOD

Twenty-four sheep were commenced on VV ECMO. Parasternal long-axis (Plax) and short-axis (Psax) views were obtained pre- and postcontrast while on VV ECMO. Endocardial definition scores (EDS) per segment were graded: 1 = good, 2 = suboptimal 3 = not seen. Endocardial border definition score index (EBDSI) was calculated for each view. Endocardial length (EL) in the Plax view for the left ventricle (LV) and right ventricle (RV) was measured.

RESULTS

Summation EDS data for the LV and RV for unenhanced TTE (UE) versus CE TTE imaging: EDS 1 = 289 versus 346, EDS 2 = 38 versus 10, EDS 3 = 33 versus 4, respectively. Wilcoxon matched-pairs rank-sign tests showed a significant ranking difference (improvement) pre- and postcontrast for the LV (P < 0.0001), RV (P < 0.0001) and combined ventricular data (P < 0.0001). EBDSI for CE TTE was significantly lower than UE TTE for the LV (1.05 ± 0.17 vs. 1.22 ± 0.38, P = 0.0004) and RV (1.06 ± 0.22 vs. 1.42 ± 0.47, P = 0.0.0006) respectively. Visualized EL was significantly longer in CE versus UE for both the LV (58.6 ± 11.0 mm vs. 47.4 ± 11.7 mm, P < 0.0001) and the RV (52.3 ± 8.6 mm vs. 36.0 ± 13.1 mm, P < 0.0001), respectively.

CONCLUSIONS

Despite exposure to destructive hydrodynamic forces, CE is a feasible technique in an ovine ECMO model. CE results in significantly improved EDS and increased EL.

Optimal management of the critically ill: anaesthesia, monitoring, data capture, and point-of-care technological practices in ovine models of critical care

Animal models of critical illness are vital in biomedical research. They provide possibilities for the investigation of pathophysiological processes that may not otherwise be possible in humans. In order to be clinically applicable, the model should simulate the critical care situation realistically, including anaesthesia, monitoring, sampling, utilising appropriate personnel skill mix, and therapeutic interventions. There are limited data documenting the constitution of ideal technologically advanced large animal critical care practices and all the processes of the animal model. In this paper, we describe the procedure of animal preparation, anaesthesia induction and maintenance, physiologic monitoring, data capture, point-of-care technology, and animal aftercare that has been successfully used to study several novel ovine models of critical illness. The relevant investigations are on respiratory failure due to smoke inhalation, transfusion related acute lung injury, endotoxin-induced proteogenomic alterations, haemorrhagic shock, septic shock, brain death, cerebral microcirculation, and artificial heart studies. We have demonstrated the functionality of monitoring practices during anaesthesia required to provide a platform for undertaking systematic investigations in complex ovine models of critical illness.

A novel echocardiographic imaging technique, intracatheter echocardiography, to guide veno-venous extracorporeal membrane oxygenation cannulae placement in a validated ovine model

Background

Echocardiography plays a fundamental role in cannulae insertion and positioning for extracorporeal membrane oxygenation (ECMO). Optimal access and return cannulae orientation is required to prevent recirculation. The aim of this study was to compare a novel imaging technique, intracatheter echocardiography (iCATHe), with conventional intracardiac echocardiography (ICE) to guide placement of ECMO access and return venous cannulae.

Methods

Twenty sheep were commenced on veno-venous ECMO (VV ECMO). Access and return ECMO cannulae were positioned using an ICE-guided technique. Following the assessment of cannulae position, the ICE probe was then introduced inside the cannulae, noting location of the tip. After 24 h, the sheep were euthanized and cannulae position was determined at post mortem. The two-tailed McNemar test was used to compare iCATHe with ICE cannulae positioning.

Results

ICE and iCATHe imaging was possible in all 20 sheep commenced on ECMO. There was no significant difference between the two methods in assessing access cannula position (proportion correct for each 90%, incorrect 10%). However, there was a significant difference between ICE and iCATHe success rates for the return cannula (p = 0.001). Proportion correct for iCATHe and ICE was 80% and 15% respectively. iCATHe was 65% more successful (95% CI 27% to 75%) at predicting the placement of the return cannula. There were no complications related to the ICE or iCATHe imaging.

Conclusion

iCATHe is a safe and feasible imaging technique to guide real-time VV ECMO cannulae placement and improves accuracy of return cannula positioning compared to ICE.

Electronic supplementary material

The online version of this article (doi:10.1186/2197-425X-2-2) contains supplementary material, which is available to authorized users.