Role of Transfusion Volume and Transfusion Rate as Markers of Futility During Ultramassive Blood Transfusion in Trauma.

BACKGROUND: Using a large national database, we evaluated the relationship between RBC transfusion volume, RBC transfusion rate, and in-hospital mortality to explore the presence of a futility threshold in trauma patients receiving ultramassive blood transfusion. STUDY DESIGN: The ACS-TQIP 2013 to 2018 database was analyzed. Adult patients who received ultramassive blood transfusion (≥20 units of RBC/24 hours) were included. RBC transfusion volume and rate were captured at the only 2 time points available in TQIP (4 hours and 24 hours), or time of death, whichever came first. RESULTS: Among 5,135 patients analyzed, in-hospital mortality rate was 62.1% (n = 3,190), and 4-hour and 24-hour mortality rates were 17.53% (n = 900) and 42.41% (n = 2,178), respectively. RBC transfusion volumes at 4 hours (area under the receiver operating characteristic curve [AUROC] 0.59 [95% CI 0.57 to 0.60]) and 24 hours (AUROC 0.59 [95% CI 0.57 to 0.60]) had low discriminatory ability for mortality and were inconclusive for futility. Mean RBC transfusion rates calculated within 4 hours (AUROC 0.65 [95% CI 0.63 to 0.66]) and 24 hours (AUROC 0.85 [95% CI 0.84 to 0.86]) had higher discriminatory ability than RBC transfusion volume. A futility threshold was not found for the mean RBC transfusion rate calculated within 4 hours. All patients with a final mean RBC transfusion rate of ≥7 U/h calculated within 24 hours of arrival experienced in-hospital death (n = 1,326); the observed maximum length of survival for these patients during the first 24 hours ranged from 24 hours for a rate of 7 U/h to 4.5 hours for rates ≥21 U/h. CONCLUSION: RBC transfusion volume within 4 or 24 hours and mean RBC transfusion rate within 4 hours were not markers of futility. The observed maximum length of survival per mean RBC transfusion rate could inform resuscitation efforts in trauma patients receiving ongoing transfusion between 4 and 24 hours.

Predictors of relapse and efficacy of rituximab in immune thrombotic thrombocytopenic purpura.

Patients with immune-mediated thrombotic thrombocytopenic purpura (iTTP) often experience life-threatening relapses of the disease, and rituximab (RTX) can be used to mitigate relapse risk. However, the predictors of relapse in iTTP and the magnitude and duration of effect of RTX remain key unanswered questions. Using a multi-institutional cohort of consecutive adult patients with iTTP, we used survival analysis to compare relapse rates between patients who received RTX during the index presentation with acute iTTP and those who did not. Of 124 patients, 60 (48%) received RTX and 34 (27%) experienced relapse. Median time to relapse was 3.71 (interquartile range, 1.75-4.9) and 1.33 (interquartile range, 0.43-2.35) years for RTX-treated and untreated patients, respectively. RTX conferred protection from relapse at 1 year of follow-up (P = .01) but not at 5 years of follow-up. Extended Cox regression was then used to identify predictors of relapse and to estimate the protective effect of RTX. The following parameters were independently associated with increased risk for subsequent relapse: presenting in iTTP relapse (hazard ratio [HR], 2.97; 95% confidence interval [CI], 1.4-6.4), age younger than 25 years (HR, 2.94; 95% CI, 1.2-7.2), and non-O blood group (HR, 2.15; 95% CI, 1.06-4.39). RTX initially provided protection from relapse (HR, 0.16; 95% CI, 0.04-0.70), but this effect gradually diminished, returning to the baseline risk for untreated patients at approximately 2.6 years. Patients who are young, have non-O blood group, or present with relapsed iTTP are at increased risk for subsequent relapse. RTX appears to confer short-term protection from relapse.

Treatment with or without plasma exchange for patients with acquired thrombotic microangiopathy not associated with severe ADAMTS13 deficiency: a propensity score-matched study.

BACKGROUND: Therapeutic plasma exchange (TPE) is a proven treatment for thrombotic thrombocytopenic purpura (TTP) characterized by severe ADAMTS13 deficiency, but the efficacy of TPE in suspected TTP with an ADAMTS13 activity level of more than 10% remains controversial. STUDY DESIGN AND METHODS: We conducted a propensity score (PS)-matched study of 186 adult patients included in the Harvard Thrombotic Microangiopathy (TMA) Research Collaborative registry who presented with TMA suggestive of TTP but an ADAMTS13 activity level of more than 10%. RESULTS: Before matching, patients treated with TPE (n = 71) differed from untreated patients (n = 115) by several clinical measures. PS matching was performed to address clinical disparities between the two groups and resulted in a well-balanced cohort of 59 TPE-treated patients paired with 59 untreated controls, all of whom had TMA. After matching, we observed no significant difference in the primary outcome of 90-day survival between the treated and untreated groups (hazard ratio, 0.88; 95% confidence interval [CI], 0.44-1.77; p = 0.72). In-hospital mortality (odds ratio [OR], 0.77; 95% CI, 0.34-1.75; p = 0.53) and the percentage of patients with platelet count recovery (OR, 1.58; 95% CI, 0.77-3.26; p = 0.21) also did not differ significantly between the two matched groups. CONCLUSION: Our data suggest that routine use of TPE in the diverse group of TMA patients without severe ADAMTS13 deficiency may not significantly improve outcomes.

A systematic review of transfusion-associated graft-versus-host disease.

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare complication of blood transfusion. The clinicolaboratory features of TA-GVHD and the relative contributions of recipient and component factors remain poorly understood. We conducted a systematic review of TA-GVHD reports. The HLA relationship between donor and recipient was classified as D = 0 when no donor antigens were foreign to the recipient vs D ≥ 1 when ≥1 donor antigen disparity occurred. We identified 348 unique cases. Criteria for component irradiation were met in 48.9% of cases (34.5% immune-compromised, 14.4% related-donor), although nonirradiated components were transfused in the vast majority of these (97.6%). Components were typically whole blood and red cells. When reported, component storage duration was ≤10 days in 94%, and 23 (6.6%) were leukoreduced (10 bedside, 2 prestorage, and 11 unknown). Among 84 cases with HLA data available, the category of D = 0 was present in 60 patients (71%) at either HLA class I or II loci and was more common among recipients without traditional indications for component irradiation. These data challenge the historic emphasis on host immune defects in the pathogenesis of TA-GVHD. The dominant mechanism of TA-GVHD in both immunocompetent and compromised hosts is exposure to viable donor lymphocytes not recognized as foreign by, but able to respond against, the recipient.