Type-O Blood Is Not Associated With Elevated Mortality After Trauma: A North American Cohort Study

BACKGROUND

Recent studies have presented contradictory findings on the relationship between blood type and mortality in trauma patients. Using the largest population in a study of this type to date, we hypothesized that ABO genotype and Rhesus status would influence trauma-related mortality and morbidity given the relationship between blood type and hemostasis.

METHODS

Data from all trauma patients admitted to level I and level II trauma centers in one city over a five-year period was retrospectively analyzed. Patients were stratified by ABO type. Patient demographics and outcomes were then assessed. Chi-squared and Fisher's exact tests were used to analyze categorical variables. Continuous variables were analyzed using ANOVA or Kruskal-Wallis tests as appropriate. Logistic regression was used to determine independent associations for 28-day mortality and complications.

RESULTS

Of 5249 patients, severe injury (ISS >15) was present in 1469. Approximately one-quarter of patients with severe injury received blood products within the first 24 hours. There were no significant variations in demographics or complications between patients of different blood types. Univariate and multivariable regression analysis showed no association between blood type and mortality. However, penetrating injury, lower GCS, higher ISS, blood transfusion within 24 hours, and Asian descent were associated with higher overall mortality.

CONCLUSIONS

In contrast to previous studies, we found no evidence of an association between blood type and mortality. However, our findings suggest that patients of Asian descent may be at higher risk for mortality following trauma. Further research is warranted to explore this observation.

Desirability of Outcome Ranking and Response Adjusted for Antibiotic Risk (DOOR/RADAR) Post Hoc Analysis Supports Equipoise for Antibiotic Initiation Strategies in Intensive Care Unit-Acquired Pneumonia

Background: Pneumonia is the most common intensive care unit (ICU)-acquired infection and source of potential sepsis in ICU populations but can be difficult to diagnose in real-time. Despite limited data, rapid initiation of antibiotic agents is endorsed by society guidelines. We hypothesized that a post hoc analysis of a recent randomized pilot study would show no difference between two antibiotic initiation strategies. Patients and Methods: The recent Trial of Antibiotic Restraint in Presumed Pneumonia (TARPP) was a pragmatic cluster-randomized pilot of antibiotic initiation strategies for patients with suspected ICU-acquired pneumonia. Participating ICUs were cluster-randomized to either an immediate initiation protocol or a specimen-initiated protocol where a gram stain was required for initiation of antibiotics. Patients in the study were divided into one of seven mutually exclusive outcome rankings (desirability of outcome ranking; DOOR): (1) Survival, No Pneumonia, No adverse events; (2) Survival, Pneumonia, No adverse events; (3) Survival, No Pneumonia, ventilator-free-alive days ≤14; (4) Survival, Pneumonia, ventilator-free-alive days ≤14; (5) Survival, No Pneumonia, Subsequent episode of suspected pneumonia; (6) Survival, Pneumonia, Subsequent episode of suspected pneumonia; and (7) Death. These rankings were further refined using the duration of antibiotics prescribed for pneumonia (response adjusted for antibiotic risk; RADAR). Results: There were 186 patients enrolled in the study. After applying the DOOR analysis, a randomly selected patient was equally likely to have a better outcome in specimen-initiated arm as in the immediate initiation arm (DOOR probability: 50.8%; 95% confidence interval [CI], 42.7%-58.9%). Outcome probabilities were similar after applying the RADAR analysis (52.5%; 95% CI, 44.2%-60.6%; p = 0.31). Conclusions: We found that patients for whom antibiotic agents were withheld until there was objective evidence (specimen-initiated group) had similar outcome rankings to patients for whom antibiotic agents were started immediately. This supports the findings of the TARPP pilot trial and provides further evidence for equipoise between these two treatment strategies.

Provider Perceptions of Antibiotic Initiation Strategies for Hospital-Acquired Pneumonia

Background: The practice of rapidly initiating antibiotic therapy for patients with suspected infection has recently been criticized yet remains commonplace. Provider comfort level has been an understudied aspect of this practice. Hypothesis: We hypothesized that there would be no significant differences in provider comfort level between the two treatment groups. Methods: We prospectively surveyed critical care intensivists who provided care for patients enrolled in the Trial of Antibiotic Restraint in Presumed Pneumonia (TARPP), which was a multicenter cluster-randomized crossover trial that evaluated an immediate antibiotic initiation protocol compared with a protocol of specimen-initiated antibiotic initiation in ventilated patients with suspected new-onset pneumonia. At the end of each enrollment arm, physicians at each center were surveyed regarding their overall comfort level with the recently completed treatment arm, and perception of adherence. Both a paired and unpaired analysis was performed. Results: We collected 51 survey responses from 31 unique participants. Providers perceived a higher rate of adherence to the immediate initiation arm than the specimen-initiated arm (Always Adherent: 37.5% vs. 11.1%; p = 0.045). Providers were less comfortable waiting for objective evidence of infection in the specimen-initiated arm than with starting antibiotic agents immediately (Very Comfortable: 83.3% vs. 40.7%; p = 0.004). For the smaller paired analysis, there was no longer a difference in comfort level. Conclusions: There may be differences in provider comfort levels and perceptions of adherence when considering two different antibiotic initiation strategies for suspected pneumonia in ventilated patients. These findings should be considered when planning future studies.

Abstract P2-09-02: Modulation of the immune microenvironment in high risk DCIS by intralesional injection of anti-PD-1 (pembrolizumab)

Background. Ductal carcinoma in situ (DCIS) is a risk factor for the subsequent development of invasive breast cancer. Features of DCIS that are associated with a high risk of a subsequent event include large size (> 5 cm), high grade, comedo necrosis, palpable mass, hormone receptor negativity, and HER2 positivity. We have previously shown that immune infiltrates are positively associated with these high-risk features, suggesting that manipulating the immune microenvironment in high-risk DCIS, for example via checkpoint blockade, could potentially alter disease progression.

Methods. In this phase 1 pilot study we investigated changes in the immune microenvironment of high risk DCIS after intralesional injection of anti-PD-1 (pembrolizumab). Study participants received 2 intralesional injections of pembrolizumab, 3 weeks apart, with surgery approximately 3 weeks after the 2nd dose. The study started with a dose of 2 mg/injection (1/100 of the standard 200 mg iv dose), then escalated to 4 mg and 8 mg, with 3 patients at each dose. Tissue samples from pre-treatment biopsies and post-treatment surgical resections were stained with two 6-plex immune panels using Opal immunofluorescence reagents (Perkin Elmer) on a fully automated Ventana Discovery platform, imaged with a Vectra 3 system and analyzed with inForm software (Perkin Elmer). An algorithm for tumor/stroma segmentation developed in inForm was used to randomly select 10 high power fields (hpfs) for imaging. Cell phenotype maps were generated for each of these hpfs for each sample. Cell densities were determined per area of stroma, DCIS, or total tissue and averaged across all hpfs for a given case. Spatial analyses were performed to quantitate co-localization of immune cells with DCIS cells.

Results. The intralesional injections were easily administered and well tolerated. No systemic toxicities were observed at any dose. MRI imaging demonstrated no change in the size of lesions after treatment. Multiplex immunofluorescence analyses demonstrated heterogeneous responses ranging from dramatic increases in T cells, in particular CD8+ T cells, in cases which had a T cell infiltrate prior to therapy, to no post-therapy T cell infiltrate in cases with a pre-therapy immune desert. We also observed increases in B cells and macrophages and a decrease in the ratio of FoxP3+ T cells to CD8+ T cells, the latter mainly due to a significant increase in CD8+ cells, as opposed to a decrease in FoxP3+ cells. Spatial analyses indicated that in some cases, despite a marked increase in T cells post therapy, these cells did not co-localize with DCIS cells, indicating a state of immune exclusion.

Conclusions. We have demonstrated the safety and feasibility of intralesional injection of an immune checkpoint inhibitor (pembrolizumab) in high risk DCIS. In some patients we observed a dramatic change in the immune microenvironment, with an increase in T cells, B cells, and macrophages, and a decrease in the FoxP3:CD8 ratio, even at a dose that is 1/100 of the standard intravenous clinical dose. An expansion study is underway in which patients will receive 4 injections of pembrolizumab at 3 week intervals prior to going to surgery to determine if more injections/time will increase response rate.

Citation Format: Campbell MJ, McCune E, Rothschild H, Bolen J, VandenBerg S, Chien J, Wong J, Esserman L. Modulation of the immune microenvironment in high risk DCIS by intralesional injection of anti-PD-1 (pembrolizumab) [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 P2-09-02.