22.10 Rapamycin Improves Adaptive Venous Remodeling and Decreases Arteriovenous Fistula Wall Thickening

Posted on January 31, 2019

A. Fereydooni1,2, X. Guo2,3, H. Hu2, T. Isaji2, N. Nassiri4, L. Zhang3, A. Dardik2,4  1Howard Hughes Medical Institute,Chevy Chase, MD, USA 2Vascular Biology And Therapeutics Program,Yale School Of Medicine,NEW HAVEN, CT, USA 3Renji Hospital, Shanghai Jiaotong University,Department Of Vascular Surgery,Shanghai, SHANGHAI, China 4Yale University School Of Medicine,Department Of Surgery, Section Of Vascular And Endovascular Surgery,New Haven, CT, USA

Introduction: Arteriovenous fistulae (AVF) continue to be the most common access created for hemodialysis, but up to 50% of AVFs fail to mature, suggesting a need to improve AVF maturation. In a mouse model, Akt1 expression increases during AVF maturation and reduced Akt1 expression in vivo reduces fistula wall thickness and diameter and improves long-term patency.  Mammalian target of rapamycin (mTOR) is a key regulatory protein that integrates signals from the Akt pathway to coordinate cell growth and proliferation. We hypothesized that inhibition of the Akt1-mTORC1 axis reduces pathologic venous remodeling that is associated with failure of AVF maturation.

Methods:  A C57BL6/J mouse aortocaval fistula model was used (male, 9–12 weeks). Mice were injected with 0 or 100 μg of rapamycin (intraperitoneal) daily.  The AVF (venous limb) of control- and rapamycin-injected mice were harvested at days 0, 3, 7 and 21 and for comparison analysis.  Post-operative vessel remodeling was assessed using serial ultrasound measurements of the AVF diameter and computer morphometry to measure vessel wall thickness.  AVF were compared for leukocyte, M1 and M2 macrophage surface markers and expression level of Akt1 signaling proteins using Western blot and immunofluorescence (IF) intensity.

Results: Rapamycin reduced AVF wall thickness (day 3, 4.4 μm vs 7.6 μm; day 7, 4.7 μm vs 17.8 μm; day 21, 6.2 μm vs 42.2 μm; p<0.01; n=4), without any change in AVF diameter (1-11% reduction in relative diameter; p>0.5 for day 21; n=6).  Rapamycin decreased PCNA expression (day 3 and 7, p< 0.05; n=3), but did not increase cleaved caspase-3 expression (day 3, 7, and 21 p>0.05; n=3) in AVF.  Deposition of collagen I, collagen III and fibronectin also decreased in AVF of rapamycin-treated mice, compared to control mice (41-63% reduction in IF intensity of all three markers at day 21, p< 0.05 for collagen I and III day 7 and 21; n=4; p< 0.01 for fibronectin day 3, 7 and 21; n=5).  Rapamycin treatment was associated with diminished phosphorylation of the mTORC1 pathway: Akt1, 4EBP1 and p70S6K (p<0.001; n=5-7), but not of the mTORC2 pathway: PKC-α  and SGK1 (p>0.4; n=4).  Both leukocyte CD45+ and macrophage CD68+ protein expression increased in AVF compared to sham-operated vein (days 3, 7 and 21; p<0.05).  Macrophage depletion with clodronate liposomes reduced AVF wall thickness compared to control veins (p< 0.01, day 21; n=3). Rapamycin also reduced macrophage CD68+ protein expression as well as both M1 and M2 macrophage activity in AVF (iNOS, TNF-α, IL-10 and CD206, day 7, p<0.04; n=4).

Conclusion: Rapamycin reduces inflammation and wall thickening during AVF maturation through the Akt1-mTORC1 signaling pathway.  Rapamycin may be a translational strategy to improve AVF patency.

 

22.09 Immunologic Profiling of Rejection Risk in HIV-Positive Solid Organ Transplant Recipients

Posted on January 31, 2019

S. N. Chu2, S. Wisel1, B. Shaw1, K. Lee1, M. Mintz1, C. Ward1, E. Chuu1, K. Melli1, K. Sugisaki1, P. Stock1, Q. Tang1  1University Of California – San Francisco,Department Of Surgery,San Francisco, CA, USA 2University Of California – San Francisco,School Of Medicine,San Francisco, CA, USA

Introduction:  HIV(+) solid­ organ transplant recipients are predisposed to a three times higher rate of rejection episodes when compared to HIV(­-) recipients, but immunological correlates of rejection in this population have not previously been identified. Here we describe our investigation of immunologic phenotype and gene expression profiling to identify functional differences between Rejectors (Rej) and Non­-Rejectors (NR).

Methods:  Donor and recipient peripheral blood mononuclear cells (PBMCs) were collected prior to transplant. Rej were selected based on biopsy­-proven acute cellular rejection. Kidney transplant recipients were stratified by Rej (n=28) versus NR (n=56), as compared to matched HIV(­-) kidney transplant recipients, HIV(+) non­transplant controls and HIV(­-), ESRD(­-) healthy control subjects (n=25 per group). These patients were profiled using flow cytometric panels to characterize cellular subsets, activation status, and Treg phenotype. Groups were compared for variance using the Kruskal­-Wallis test, with pairwise comparison performed between groups by Dunn’s post­-test. For gene expression analysis, pre­-transplant HIV(+) liver recipient PBMCs from Rej (n=6) and NR (n=6) were co­-cultured in mixed lymphocyte reaction (MLR) in vitro with either CD40L-­stimulated donor or 3rd party B cells. Donor B cells were removed by immunodepletion and recipient cells were analyzed using a custom NanoString panel. Raw counts were normalized and p­-values were adjusted using the Benjamini­-Hochberg procedure.

Results: HIV(+) Rej were found to have markers of increased pre­-transplant immune activation as compared to NR, with a bias toward activation of the innate immune system. They exhibited a significantly altered monocyte phenotype, including decreased HLA­-DR expression on CD14+CD16+ intermediate monocytes. Moreover, Rej have increased B cell activation by HLA­-DR expression and less activated Tregs by decreased percentage of CD39+ Tregs. The frequency of Tregs did not differ between the two groups. After alloantigen stimulation, Rej showed increased gene expression of T­-cell activation markers, CD28 and ICOS. Interestingly, NR displayed upregulation of regulatory ligands in the leukocyte immunoglobulin­like receptor (LILR) family, including LILRB1, LILRA1, LILRB4, as well as a higher proportion of PD1+ CD8+ T cells compared to Rej. Differential gene expression was preserved irrespective of stimulus by either donor or 3rd party.

Conclusion: Overall, our results suggest that increased rates of rejection in HIV(+) kidney and liver transplants correlate with pre­-transplant, recipient­-specific immune dysfunction. Concordance in gene expression profile following stimulation with donor or 3rd party suggests that differential gene expression is an intrinsic, recipient­-driven propensity to immune activation in Rej and immune regulation in NR.

22.08 Setting of Care in Colon Cancer: Which Patients Benefit the Most from Care at Academic Centers?

Posted on January 31, 2019

J. K. Ewing1, J. J. Cabo1, X. Shu2, X. O. Shu2, M. Tan1, K. Idrees1, C. E. Bailey1  1Vanderbilt University Medical Center,Department Of Surgery, Division Of Surgical Oncology And Endocrine Surgery,Nashville, TN, USA 2Vanderbilt University Medical Center,Division Of Epidemiology,Nashville, TN, USA

Introduction: Some studies show that care at an academic center (AC) improves survival for patients with advanced stage colon cancer (CC). However, it remains unclear which patients have the greatest survival benefit from treatment at AC. The primary aim of this study is to determine which patients have the most improvement in overall survival (OS) from treatment at AC, relative to other treatment facilities (TF).

Methods: A retrospective cohort study of adults with histologically confirmed CC was performed using the National Cancer Database (2004-2014). TF were classified as community cancer programs (CCP; 100-500 cases/year), comprehensive community cancer programs (CCCP; >500 cases/yr), academic centers (AC; >500 cases/yr with residency training program), or integrated network cancer programs (INCP; multi-center organizations). Demographic and clinical factors were compared according to TF. Kaplan-Meier curves and log-rank tests were used for univariate survival analysis. Cox proportional hazard models were used to assess the impact of TF on OS after adjusting for patient, tumor, and treatment characteristics.  Subgroup analyses were performed stratifying by stage, age, and race.

Results:The cohort included 433,997 patients with median age of 69(Interquartile range: 59-78). Most were white(83.8%), had Medicare(55.4%) or private insurance(34.8%), and were treated at CCCP(49.1%) or AC(26.5%). Median OS was greatest for patients treated at AC(107.1 months), compared to INCP(98.5 mo), CCCP(95.9 mo), and CCP(90.2 mo) (P<0.001). On multivariate analysis, there was no significant difference in OS between patients with stage IV CC treated at CCCP or INCP relative to those treated at CCP. However, an improvement in OS was observed for patients with stage IV CC treated at AC(Hazard ratio [HR] 0.85, 95% Confidence Interval [CI] 0.83-0.87, P<0.001) (Figure 1A). Similarly, among patients younger than 70, patients treated at CCCP or INCP had similar OS relative to those treated at CCP, whereas those treated at AC had improved OS relative to those treated at CCP(HR 0.86, 95% CI 0.84-0.88, P<0.001) (Fig. 1B). Finally, for African American (AA) patients, treatment at CCCP and INCP had similar OS compared to treatment at CCP, whereas improved OS was observed for AA patients treated at AC(HR 0.88, 95% CI 0.84-.91, P<0.001). A similar pattern was observed for non-white, non-AA patients (Fig. 1C).

Conclusion:Treatment at AC is especially beneficial for patients with stage IV CC, patients younger than 70, and non-white patients. For these patients, treatment at AC was independently associated with 12-15% reduced mortality relative to treatment at CCP. Further work is needed to examine why certain groups benefit more from care at AC.

22.07 Expansion Coverage and Preferential Utilization of Cancer Surgery Among Minorities and Low-Income Groups

Posted on January 31, 2019

A. B. Crocker1, A. Zeymo1,2, J. McDermott1, D. Xiao1, T. Watson4, T. DeLeire5, N. Shara2,3, K. S. Chan1,2, W. B. Al-Refaie1,4  1MedStar-Georgetown Surgical Outcomes Research Center,Washington, DC, USA 2MedStar Health Research Institute,Washington, DC, USA 3Georgetown-Howard Universities Center for Clinical and Translational Science,Washington, DC, USA 4Department of Surgery, MedStar-Georgetown University Hospital,,Washington, DC, USA 5Georgetown McCourt School of Public Policy,Washington, DC, USA

Introduction:
Pre-Affordable Care Act (ACA) Medicaid expansions have demonstrated inconsistent effects on cancer surgery utilization rates among racial minorities and low-income Americans. Currently, it remains unknown how Medicaid expansion coverage under the ACA will impact these vulnerable populations with long standing disparities in access and outcomes of surgical cancer care. Using a quasi-experimental design, this study seeks to examine whether Medicaid expansion differentially increased the utilization of surgical cancer care for low-income groups and racial minorities in states that expanded their Medicaid program relative to states that did not.

Methods:
A cohort of over 95,000 patients aged 18-64 years who underwent cancer surgery were examined in two Medicaid expansion states (Kentucky and Maryland) vs. two non-expansion states (Florida and North Carolina). This evaluation utilized merged data from the State Inpatient Database, American Hospital Association, and the Area Resource File from the Health Resources and Services Administration for the years 2012-2015. Poisson interrupted time series analysis (ITS) were performed to examine the impact of ACA Medicaid expansion on the utilization of surgical cancer care for the uninsured overall, low-income persons, and racial and ethnic minorities after adjusting for age, sex, Elixhauser comorbidity score, population- and provider-level characteristics.

Results:
Following Medicaid expansion, the share of Medicaid patients receiving surgical cancer care in expansion states increased by 56%, compared to an 11% decrease in non-expansion states (p <0.001). Simultaneously, the percentage of uninsured patients declined by 63.4% in expansion states relative to a 10% reduction in non-expansion states (p < 0.001).  For persons from low-income zip codes, Medicaid expansion was associated with an immediate 24% increase in utilization (p = 0.002), relative to no significant change in non-expansion states. However, there were no significant trends observed post ACA expansion for racial and ethnic minorities in expansion vs. non-expansion states (Figure). 

Conclusion:
In this quasi-experimental evaluation, Medicaid expansion was associated with greater utilization of cancer surgery by low-income Americans, but provided no preferential effects for racial minorities in expansion states. Beyond the availability of coverage, these early findings highlight the need for additional investigation to uncover other factors that contribute to racial disparities in surgical cancer care.
 

22.06 Post-thyroidectomy Neck Appearance and Impact on Quality of Life in Thyroid Cancer Survivors

Posted on January 31, 2019

S. Kurumety1, I. Helenowski1, S. Goswami1, B. Peipert1, S. Yount2, C. Sturgeon1  2Feinberg School Of Medicine – Northwestern University,Department Of Medical Social Sciences,Chicago, IL, USA 1Feinberg School Of Medicine – Northwestern University,Department Of Surgery,Chicago, IL, USA

Introduction:  There is a paucity of patient-reported data on thyroidectomy scar perception. The magnitude and duration of the impact of thyroidectomy scar on quality of life (QOL) is not known. We hypothesized that age, sex and race would predict scar perception, and that worse scar perception would correlate with lower?QOL. Furthermore, we hypothesized that over time, scar perception would improve.

Methods: Adults >18 years who had undergone thyroidectomy for cancer?(n=1743)?were recruited from a support group and surveyed online. Demographics, clinical characteristics, and treatment history were assessed. Scar perception was scored on a 5-point Likert scale.?QOL was evaluated via PROMIS-29. Respondents were grouped and compared based on their responses. The relationship between scar perception, patient characteristics, and QOL were?analyzed?with univariable and multivariable?models. Kruskal-Wallis, Fisher’s exact test, and cumulative logistic regression were used to compare?categorical variables. The relationship?between PROMIS domains and scar perception?were?analyzed using Spearman partial correlation coefficients?(r)?adjusted for age and years after surgery.?Holms-Bonferroni was used to correct for multiple comparisons.

Results: Increasing age?was associated with?better?scar perception (OR 0.975/year; 95% CI 0.967-0.983; p<0.001).?71% of respondents age >45?years?reported no concern over scar, compared to only 53% of respondents?<45;?p < 0.0001. Increased time since surgery?was?also associated with?improved?scar perception (OR 0.962/year; 95% CI 0.947-0.977; p<0.0001), but there was no statistically significant difference between current and baseline neck appearance >2 years after surgery. On multivariable analysis, age >45 years (OR 0.65; [0.52-0.81] p=0.0001), >2 years since surgery (OR 0.57; 95% CI 0.46-0.70; p<0.0001), and higher self-reported QOL (OR 0.77; 95% CI 0.67-0.89; p=0.0003) were independent predictors of better self-reported scar appearance. In patients <2 years after surgery (n=568), the PROMIS domains of anxiety (rs=0.19; p<0.0001), depression (rs=0.21; p<0.0001), social function (rs=-0.18; p<0.0001), and fatigue (rs=0.21; p<0.0001) had weak but statistically significant associations with worse scar appearance. Sex and race/ethnicity were not associated with scar perception.

Conclusions: This is the largest study conducted in the U.S to evaluate scar perception after thyroidectomy, and the first to use PROMIS measures.??Age >45, >2 years since surgery, and higher self-reported QOL were independent predictors of better scar perception.??There was no significant difference between perception of current and baseline neck appearance in the group of respondents >2 years after thyroidectomy. There was a weak correlation between scar perception?and?PROMIS domains in patients who had surgery within 2 years. The impact of thyroidectomy scar on QOL appears to be mild and transient and plateaus after 2 years.

22.05 The Human Antibody and Cellular Response to MHC Compatible Swine Cell

Posted on January 31, 2019

J. M. Ladowski1, G. Martens1, L. Reyes1, M. Tector1, A. J. Tector1  1University Of Alabama at Birmingham,Birmingham, Alabama, USA

Introduction:  Xenotransplantation is a solution to the growing need for life-saving transplantable organs. Recent advances in genetic engineering allow for rapid manipulation of the swine genome. We hypothesize that genetically engineered cells possessing recipient-matched class I major histocompatibility complex (MHC), on a swine MHC deficient background, would reduce both antibody- and cellular-mediated rejection.

Methods:  Two CRISPR gRNA plasmids were designed to remove the entire coding sequence of the swine class I MHC and co-transfected with a third plasmid containing a promoterless Hygromycin resistance gene surrounded by PhiC31 recombinase sequences, followed with a promoterless human class I MHC cDNA. The response of MHC-matched individuals to the human MHC expressing swine cell was evaluated in a flow cytometry crossmatch (FCXM), 24-hour IFN-y ELISPOT assay, and a mixed lymphocyte reaction (MLR) to measure an immediate, recall, and delayed response.  

Results: A cell line expressing human class I MHC was successfully generated using the described approach. Individuals with no preformed to the class I MHC chosen in this experimental model demonstrated significantly less IgG antibody binding to the human MHC positive swine cell compared to the MHC deficient parent line (one-way ANOVA, p < 0.0001). The ELISPOT revealed significantly more IFN-y release for both MHC-matched and non-MHC-matched individuals in response to the human MHC positive swine cell line (paired two-tailed Wilcoxon test, p = 0.0078 and 0.0156 respectively). A human MHC expressing swine cell elicited less, but not significant, proliferation in the MLR assay compared to the swine MHC expressing cell for MHC-matched but significantly less for non-MHC-matched individuals (Figure 1 unpaired, two-tailed Wilcoxon test p = 0.1250 and 0.0312 respectively).

Conclusion: The development of the CRISPR/Cas9 system allows for complex genetic engineering strategies to be achieved rapidly. This study demonstrates that expression of human MHC on a MHC devoid swine cell can reduce the humoral and cellular response for MHC-matched individuals, but may result in a higher recall response as measured by IFN-y production.

Figure 1:  Results of the proliferation in the CFSE-based MLR of HLA-A2 positive (Figure 1A) and HLA-A2 negative (Figure 1B) PBMC responders to the HLA-A2+ AEC (Lane 1) and SLA class I positive AEC (Lane 2). An unpaired, two-tailed Wilcoxon test for the four HLA-A2 positive responders found no statistical significance between the HLA-A2 positive AEC vs the SLA class I positive AEC (p = 0.1250). For the six HLA-A2 negative responders, statistical difference was found between the HLA-A2 positive AEC vs the SLA class I positive AEC (*, p = 0.0312).

22.04 Learning from England’s Best Practice Tariff: Process Measure Pay-for-Performance Can Improve Outcomes

Posted on January 31, 2019

C. K. Zogg1,2,3, D. Metcalfe3, A. Judge4, D. C. Perry3, M. L. Costa3, B. J. Gabbe5, A. H. Haider2  1Yale University School Of Medicine,New Haven, CT, USA 2Brigham And Women’s Hospital,Center For Surgery And Public Health,Boston, MA, USA 3University of Oxford,Oxford, United Kingdom 4University of Bristol,Bristol, United Kingdom 5Monash University,Melbourne, Australia

Introduction: Since passage of the Patient Protection and Affordable Care Act in 2010, Medicare has renewed efforts to improve the quality of older adult health through the introduction of an expanding set of outcome-based readmission and mortality pay-for-performance (P4P) measures. Among trauma patients, potential P4P has met with mixed success given concerns about the heterogeneous nature of patients that trauma providers treat and resultant variations in outcome measures. A novel approach taken by the National Health Service in England could offer a viable alternative plan. The objective of this study was to assess the effectiveness of the 2007-2010 English provider consensus-driven, process measure-based P4P Hip Fracture Best Practice Tariff (BPT) on improving trauma outcomes.

Methods: Quasi-experimental interrupted time-series and difference-in-difference analysis of 2000-2014 death certificate-linked data from England (Hospital Episode Statistics), Scotland (Scottish Morbidity Records), and the United States (100% Medicare all-payer claims). The study compared before-and-after differences in English temporal trends relative to those of Scotland and the US. Outcomes included: 30/90/365-day mortality, readmission, index hospital length of stay, and time to surgery. The study also assessed projections for the number of lives saved and readmissions averted were the BPT to be implemented in Scotland and the US.

Results: A total of 878,860 English, 97,487 Scottish, and 2,994,748 US index fractures were included among adults ≥65y. Following BPT introduction in England, 30-day mortality decreased instantaneously by an absolute value of -2.6 (95%CI -3.5, -1.7) percentage-points and continued to drop by an average of -0.2 (-0.4, -0.1) percentage-points per year (DID-Scotland: -1.6; DID-US: -2.2). 90-day mortality decreased more precipitously, dropping by an absolute value of -5.6 (-7.1, -4.2) percentage-points and an annual average thereafter of -0.2 (-0.5, 0.0) percentage-points per year (DID-Scotland: -1.9; DID-US: -2.9). Similar improvements were observed in readmission (e.g. 30-day ITSA: -1.4 [-2.3, -0.5]), time to surgery, and length of stay. Projections suggest that were the BPT to be implemented in Scotland and the US (Figure), by 2030, as many as 1,377 Scottish and 11,434 US lives could be saved.

Conclusion: In contrast to outcome-based P4P, process measure P4P such as that implemented through the English Hip Fracture BPT could result in significant improvements in outcomes for US patients while remaining more applicable to heterogeneous trauma populations and acceptable to trauma providers. As efforts to improve older adult health continue to increase, there are important lessons to be learned from initiatives like the BPT

22.03 Targeted Checklist Compliance with Oral and Mechanical Prep Improves Surgical Site Infection Rates

Posted on January 31, 2019

C. L. Antonacci1, D. Armellino2, K. Cifu-Tursellino2, M. E. Schilling2, S. Dechario2, G. Husk2, M. Jarrett2, A. Antonacci2  1Tulane University School Of Medicine,New Orleans, LA, USA 2North Shore University And Long Island Jewish Medical Center,Manhasset, NY, USA

Introduction:

In addition to increased patient morbidity and mortality, National Surgical Quality Improvement Program data suggest that surgical site infection (SSI) accounts for a 9.2% increase in hospital costs above uncomplicated colectomy cases.  This project, which included 12 acute care facilities, was designed to reduce the incidence of post-colectomy SSI by implementing a system-wide standardized surgical bundle checklist, monthly communication of outcome data to practitioners and analysis of factors contributing to organ space infection, as defined by the National Healthcare Safety Network (NHSN). 

Methods:

A colectomy bundle checklist was utilized to gather information on clinical practice from 761 colectomy cases within our system from 1/1/2016 to 12/31/2017.  Data was entered into a relational database analyzing over 50 patient, procedure, SSI and bundle compliance elements at the system, hospital and surgeon level.   Documentation compliance with the checklist items was compared to surgeon specific NHSN infection rates (< 2.5% and > 2.5%) by paired Student’s t-test.

Results:

Compared to 2016, elective post-colectomy SSIs for our health system in 2017 were reduced by 33% with a 45.3% reduction in intrabdominal infections, a 71.4% reduction in deep space infections and a 6.1% reduction in superficial site infections.  Bundle checklist compliance was analyzed with respect to pre-operative use of oral antibiotics, mechanical bowel prep, and intra-operative re-dosing of IV antibiotics. Of 540 elective colectomy cases, 420 (77.78%) were in compliance with regard to oral antibiotics, 468 (86.67%) with mechanical bowel prep, and 441 (81.67%) with re-dosing IV antibiotics. Of 39 surgeons with checklist data and NHSN reported infections, 4 (10.26%) had infection rates less than 2.5%, while 35 (89.74%) had infection rates greater than 2.5%.  Statistically significant differences were observed in checklist compliance between surgeons with infection rates <2.5% and >2.5%, respectively, for: (1) oral antibiotics 186/217 (85.7%) v. 87/134 (64.9%), p < 0.002; and (2) mechanical bowel prep 194/217 (89.4%) v. 36/65 (55.5%), p<0.006.  The use of intra-operative re-dosing of IV antibiotics 171/217 (78.8%) v. 113/130 (86.9%) was not significantly different.

Conclusion:

These data suggest that implementing a system-wide standardized surgical bundle checklist  and  relational database system can significantly reduce the incidence of elective colectomy SSIs. Analysis of bundle checklist compliance between low infection rate surgeons (<2.5%) and high infection rate surgeons (>2.5%) demonstrates significantly lower utilization of pre-operative oral antibiotic and mechanical bowel preps in high infection rate surgeons. These data further suggest that target compliance rates may need to be set in the 85% to 90% range for these bundle items to achieve optimal reductions in elective colectomy SSIs. 

 

22.02 The Impact of Prehospital Whole Blood on Arrival Physiology, Shock, and Transfusion Requirements

Posted on January 31, 2019

N. Merutka1, J. Williams1, C. E. Wade1, B. A. Cotton1  1McGovern Medical School at UT Health,Acute Care Surgery,Houston, TEXAS, USA

Introduction: Several US trauma centers have begun incorporating uncrossmatched, group O whole blood into civilian trauma resuscitation. Our hospital has recently added this product to our aeromedical transport services. We hypothesized that patients receiving whole blood in the field would arrive to the emergency department with more improved vital signs, improved lactate and base deficit, and would receive less transfusions following arrival when compared to those patients receiving pre-hospital component transfusions. 

Methods: In Novemeber 2017, we added low-titer group O whole blood (WB) to each of our helicopters, alongside that of existing RBCs and plasma. We collected information on all trauma patients receiving prehospital uncrossed, emergency release blood products between 11/01/17 and 07/31/18. Patients were divided into those who received any prehospital WB and those who received only RBC and or plasma (COMP). Initial field vital signs, arrival vital signs, arrival lbaoratory values, and ED and post-ED blood products were captured. Statistical analysis was performed using STATA 12.1. Continuous data are presented as medians (25th-75th IQR) with comparisons performed using Wilcoxon ranksum. Categorical data are reported as proportions and tested for significance using Fisher’s exact test. Following univariate analyses, a multivariate model was created to evaluate post-arrival blood products, controlling injury severity score, field vital signs, and age. 

Results: 174 patients met criteria, with 98 receiving prehospital WB and 63 receiving COMP therapy. 116 WB units were transfused in the prehospital setting. Of those receiving WB prehospital, 84 (82%) received 1 U, 14 (12%) received 2U. There was no difference in age, sex, race, or injury severity scores between the two groups. While field pulse was similar (WB: median 117 vs. COMP: 114; p=0.649), WB patients had lower field systolic pressures (median 101 vs. 125; p=0.026) and were more likely to have positive field FAST exam (37% vs. 20%; p=0.053). On arrival, however, WB patients had lower pulse and higher systolic pressures than COMP patients (TABLE). There was no difference in arrival base excess and lactate values (TABLE). However, WB patients had less ED and post-ED blood transfusions than the COMP group. A multivariate linear regression model demonstrated that field WB was associated with a reduction in ED blood transfusions (corr. coef. -10.8, 95% C.I. -19.0 to -2.5; p=0.018).

Conclusion: Prehospital WB transfusion is associated with improved arrival physiology with similar degrees of shock compared to COMP treated pateints. More importantly, WB pateints received less transfusions after arrival than their COMP counterparts. 

22.01 Neural Input Modulates Aberrant Cell Fate After Extremity Trauma

Posted on January 31, 2019

C. Hwang1, C. A. Kubiak1, M. Sorkin1, C. A. Pagani1, T. Rehse1, M. A. Garada1, Z. N. Khatib1, P. Kotha1, J. Lisiecki1, D. M. Stepien1, N. D. Visser1, K. Vasquez1, A. W. James1, Y. S. Niknafs1, P. S. Cederna1, S. W. Kemp1, B. Levi1  1University Of Michigan,Surgery,Ann Arbor, MI, USA

Introduction: Heterotopic ossification (HO) is a painful, debilitating formation of ectopic bone, often found after severe polytrauma, burn and neural injury. Literature has implicated neurotrophic signals such as nerve growth factor (NGF) as crucial signals for normal bone development. Additionally,  secreted neural peptides including substance P (SP) have been demonstrated as capable of regulating osteoblast behavior, modulating osteogenic cues, and producing ectopic bone when exogenously introduced. Thus, we hypothesized that innervation is crucial to pathologic stem cell differentiation and resultant HO.

Methods: C57BL/6J male mice were stratified to burn/tenotomy (BT) or BT+neurectomy. The Achilles tendon was bisected and accompanied by 30% TBSA dorsal burn. Sciatic/sural nerves were transected at midthigh (proximal/distal to bifurcation, respectively). Hindlimbs were analyzed via µCT at 9 weeks (n=3-5/group). Sections (n=1) from the ankle were immunolabeled (IF) at 1 and 3 weeks. Myeloperoxidase (MPO) activity was measured via in vivo imaging system at the ankle at 4 days (n=4-5/group). From BT mice, mRNA was harvested from injured and uninjured tendon (n=3/group) and hybridized to Affymetrix microarray (1 week) or processed for whole transcriptome via RNAseq (3 weeks). Microarray data of human ligament cells from GEO dataset GSE5464 were analyzed using linear modeling with empirical Bayes method for differential expression.

Results: Sciatic neurectomy upon BT significantly reduced total HO (Fig A, 4.7 v. 1.57mm3, p=0.036). IF imaging of NGF and SP showed robust protein expression at 1 week with limited colocalization of F4/80 or Ly6G (Fig. B,C). Neurectomies did not cause changes in MPO levels (Fig. D). BT (Fig. E, right) induced upregulation of characteristic genes of inflammation (Il6, Ptgs2, Ptger1, Il1a, Tacr1) vs. ininjured tendon at 1 week (left). Similar upregulation was observed at 3 weeks (Fig. F). Notable neurotrophins, Ngf, Gdnf, and Brdf, were also upregulated.  GEO data exhibited parallel trends of Ngf and Brdf in human spinal ligament cells subjected to cyclic strain (Fig. G); a loading shown to be associated with ossification of connective tissues.

Conclusion: Interruption of innervation to an injury site inhibits post-traumatic ossification independent of myeloid cell infiltration (MPO) during the acute response. In mice, BT induces upregulation of neurotrophin genes in both acute and sub-acute timepoints, concordant with upregulation seen in strained human cells. BT exhibited robust labeling of NGF, spatially distinct from macrophages and PMNs, along with SP, a well characterized regulator of osteogenesis. This data suggests neural signals modulate aberrant wound healing as demonstrated by HO formation.