Impact of Hemoglobin Drop, Bleeding Events, and Red Blood Cell Transfusions on Long-term Mortality in Patients Undergoing Transaortic Valve Implantation.

BACKGROUND: Despite the minimally invasive nature of transcatheter aortic valve implantation (TAVI), the procedure is associated with several complications. We aimed to analyze the individual impact of bleeding events, hemoglobin (Hb) drop, and red blood cell (RBC) transfusions on prognosis and to evaluate the temporal trends in bleeding and RBC transfusions since the initiation of the TAVI program in our centre and onward. METHODS: Consecutive patients (n = 597) undergoing transfemoral TAVI were prospectively enrolled. Periprocedural Hb levels, RBC transfusions, and major/life-threatening bleeding events were documented and analyzed. RESULTS: In the entire cohort, mean Hb level decreased after TAVI (11.8 ± 1.4 to 9.5 ± 1.3 g/dL; P < 0.001). Major/life threatening bleeding occurred in 66 (10.1%) patients, and 179 (30%) patients received RBC transfusions. Major/life threatening bleeding was not independently associated with mortality when adjusted for Hb drop and RBC transfusion. Among patients with an Hb drop of < 3 g/dL, those who received RBC transfusions had a higher mortality (hazard ratio [HR], 1.9; confidence interval [CI], 95% CI, 1.2-2.9; P = 0.004). Among patients with an Hb drop of ≥ 3 g/dL, the Hb drop had no significant impact on survival (HR, 1.5; 95% CI, 0.7-2.9; P = 0.2); however, patients who received RBC transfusions had a significantly higher mortality (HR, 4.1; 95% CI, 2.2-7.7; P < 0.001). The use of RBC transfusions decreased gradually over the duration of the study. CONCLUSIONS: An Hb drop is frequently observed after TAVI. RBC transfusions are strongly associated with increased long-term mortality in these patients, regardless of the degree of Hb drop or major bleeding.

Increased Incidence of Red Blood Cell Alloantibodies in Myelodysplastic Syndrome.

BACKGROUND: Approximately 80% of patients with myelodysplastic syndromes (MDS) receive multiple red blood cells (RBC), often multiple transfusions, and are therefore prone to develop alloantibodies against RBC. Because of increasing evidence for the role of immune dysregulation in the pathobiology of MDS, we hypothesized that in patients with MDS there is an increase in alloantibody formation beyond that expected from multiple transfusions. OBJECTIVES: To determine the prevalence rates of alloantibodies in patients with MDS who are transfusion dependent and compare them to rates of non-MDS patients matched for number of RBC units they received. METHODS: The blood bank database was screened to identify non-MDS patients matched for age and number of units transfused. Logistic regression analysis was applied to determine factors affecting alloantibody formation. RESULTS: Of 60 patients with MDS, 18 (30%) developed alloantibodies against RBC. Transfusion-dependent MDS and non-MDS patients (N = 56 each), matched for number of RBC units and age, were compared. Fifteen MDS patients (27%) but only 12 non-MDS patients (12%) developed alloantibodies (P = 0.057). The relative risk for developing antibodies in MDS patients was 2.14, and MDS was the strongest predictor for formation of alloantibodies during transfusion therapy (odds ratio 3.66, confidence interval 1.4-9.3). CONCLUSIONS: Patients with MDS are at increased risk to develop RBC alloantibodies, partly because these patients receive multiple RBC transfusions. Whether matching for RH and KEL would lead to lower rates of RBC alloantibodies remains to be determined.

Relaparotomies after cesarean sections: risk factors, indications, and management.

OBJECTIVE: To establish the frequency of post-cesarean relaparotomy, identify its risk factors, indications, and operative management. METHODS: This study was a retrospective matched case control study. Records of all women who underwent a cesarean section (CS) from July 2006 to March 2012 were reviewed. We identified all women who had a relaparotomy within 1 month from their CS. For each woman, two women were matched. We analyzed data regarding obstetrical history, current gestation, surgical parameters, and outcome. RESULTS: A total of 14,637 CS were performed during this period, of these, 58 cases required a relaparotomy (0.4%). In univariate analysis, female sex and duration of CS were associated with an increased risk for relaparotomy. In multivariate analysis, multiple pregnancies, general anesthesia, duration of operation, and female sex, independently increased the risk for relaparotomy. The leading indications for relaparotomy were hemodynamic shock and subcutaneous hematoma. The most common interventions during relaparotomy were cauterization of subcutaneous vessels, and ligation of large vessels. Overall, women requiring relaparotomy received, on average, 16 units of blood products. CONCLUSIONS: This study highlights risk factors associated with post-cesarean relaparotomy. Surgeons might use this important data to identify women at risk beforehand, and thus, reduce the morbidity associated with relaparotomy.

Usage of blood products in multiple-casualty incidents: the experience of a level I trauma center in Israel.

OBJECTIVE: To predict how much blood will be needed based on the number of injured patients arriving after a multiple-casualty incident. DESIGN: A retrospective study evaluating data collected in 18 consecutive terrorist attacks in the city of Tel Aviv between January 1997 and February 2005. SETTING: A large, urban trauma center. PATIENTS: A total of 986 patients in 18 events. MAIN OUTCOME MEASURES: Number of packed red blood cell (PRBC) units transfused per patient. RESULTS: A total of 332 U of PRBCs were transfused. Half of the PRBC units were administered as massive transfusions to 4.7% of the patients. The number of PRBC units transfused per patient index (PPI) was related to incident size (mean [SD], 0.70 [1.60] to 1.50 [1.60]). The most frequent major blood group transfused was type O (50%). Half of the units of PRBCs were supplied during the first 2 hours. CONCLUSIONS: One unit of blood per evacuated victim is sufficient in a small multiple-casualty incident and 2 U is sufficient in a large multiple-casualty incident. Half of the PRBC units should be blood group O.

Vitamin K-dependent coagulation factors and fibrinogen levels in FFP remain stable upon repeated freezing and thawing.

BACKGROUND: FFP is considered adequate for transfusion up to 24 hours after thawing and is currently used most often to replace deficient clotting factors, such as in warfarin overdose. We set to examine the levels of vitamin K-dependent factors (i.e., prothrombin, FVII, F IX, FX), as well as fibrinogen, upon twice freezing and thawing of FFP. If factor levels in refrozen FFP remain within normal limits, this component can possibly be transfused, thus avoiding wastage of precious blood components. STUDY DESIGN AND METHODS: Twenty units of FFP, five units of each blood group A, B, AB, and O, were thawed, and aliquots were taken for measurement of coagulation factors. The plasma units were then kept for 24 hours at 4 degrees C, at which point a second aliquot was taken, The remaining FFP units were refrozen and kept at -80 degrees C for 1 week. The above procedure was then repeated. Coagulation-factor activity and fibrinogen level were measured by the coagulation analyzer. RESULTS: The mean levels of prothrombin, FVII, F IX, FX, and fibrinogen of each blood group (A, B, AB, and O) were calculated for each of four time points and found not statistically different (p > 0.05). Therefore, the rest of the analysis was done for all 20 FFP units as one group. The mean +/- SD levels of each coagulation factor at each time point demonstrated that all levels were within normal limits of all factors measured and that for none of the factors was there a significant decay of activity. CONCLUSIONS: The levels of prothrombin, FVII, F IX, FX, and fibrinogen remain stable and adequate for transfusion in twice-thawed-and-refrozen FFP. This component can be safely used for transfusion as a source of vitamin K-dependent clotting factors and fibrinogen.

Opsonization of apoptotic cells by autologous iC3b facilitates clearance by immature dendritic cells, down-regulates DR and CD86, and up-regulates CC chemokine receptor 7.

Immature dendritic cells (iDCs) do not mature after uptake of apoptotic cells and may play a role in the induction of peripheral tolerance to self antigens derived from apoptotic material. The integrins, alphavbeta3, alphavbeta5, and the scavenger receptor, CD36, have been shown to mediate uptake of apoptotic cells by iDCs. However, it is not known whether the complement system, also takes part in this process. In this study we investigated the ability of iDCs to bind to apoptotic cells opsonized by iC3b. Monocyte-derived dendritic cells were offered apoptotic Jurkat cells opsonized by autologous iC3b and labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanineperchlorate. A significant increase (P < 0.001) in the amount of cleared apoptotic cells was seen at low ratios. Despite increased efficiency of uptake, interaction between iC3b-opsonized apoptotic cells and iDCs down-regulated the expression of major histocompatibility complex class II, CD86, CC chemokine receptor (CCR)2, CCR5, and beta2-integrins (P < 0.001), and up-regulated expression of CCR7 (P < 0.001). In addition, iDC maturation responses to CD40L and lipopolysaccharide were significantly inhibited. We conclude that opsonization of apoptotic cells by iC3b induces tolerant iDCs that are able to migrate to lymph nodes.

Donor anti-Jk(a) causing hemolysis in a liver transplant recipient.

BACKGROUND: Hemolytic transfusion reactions have been observed in recipients of ABO- and/or D-mismatched marrow, peripheral blood, and solid organs. Passenger lymphocyte syndrome occurs when immunocompetent donor lymphocytes transferred during transplantation produce alloantibodies against host antigens. CASE REPORT: The first case of a delayed, anti-Jk(a)-mediated hemolytic reaction in a liver transplant recipient, caused by passenger donor lymphocytes, is reported here. A 43-year-old man underwent liver transplantation. Six weeks later, the patient underwent a second liver transplant. On Day 10 of the second transplant, clinical hemolysis ensued; anti-Jk(a) was detected. The patient's DAT became positive, and anti-Jk(a) was eluted from his RBCs. On Day 35 of the patient's second transplant, 3 weeks after the last blood transfusion, the patients' DAT was still weakly positive with anti-Jk(a) in the eluate. Six months later, serum antibody screening was negative, but the DAT was still weakly positive. The patient's RBCs tested Jk(a+), whereas the second donor's RBCs were Jk(a-). CONCLUSION: This is the first documentation of clinically significant hemolysis caused by anti-Jk(a), produced by passenger lymphocytes transferred from the donor's liver to the transplant recipient.