Red blood cell storage duration and mortality in patients undergoing percutaneous coronary intervention

Effects of transfusing older red blood cells and platelets on obstetric patient outcomes: A retrospective cohort study

OBJECTIVE

To investigate associations between transfusion of blood products close to the end of shelf-life and clinical outcomes in obstetric inpatients.

METHODS

Mortality and morbidity were compared in patients transfused exclusively with red blood cells (RBC) stored for less than 21 days (fresh) versus RBC stored for 35 days or longer (old), and platelets (PLT) stored for 3 days or fewer (fresh) versus 4 days or longer (old) in Queensland, Australia from 2007 to 2013. Multivariable models were used to examine associations between these groups of blood products and clinical end points.

RESULTS

There were 3371 patients who received RBC and 280 patients who received PLT of the eligible storage durations. Patients transfused with old RBC received fewer transfusions (2.7 ± 1.8 vs. 2.3 ± 1.0 units; P < 0.001). However, a higher rate of single-unit transfusions was also seen in those patients who exclusively received old RBC (252 [9.3%] vs. 92 [13.7%]; P = 0.003). Comparison of fresh vs. old blood products revealed no differences in the quantities of transfused RBC (9.5 ± 5.9 vs. 9.1 ± 5.2 units; P = 0.680) or PLT (1.5 ± 0.8 vs. 1.4 ± 1.1 units; P = 0.301) as well as the length of hospital stay for RBC (3 [2-5] vs. 3 [2-5] days; P = 0.124) or PLT (5 [4-8] vs. 6 [4-9] days; P = 0.120).

CONCLUSION

Transfusing exclusively older RBC or PLT was not associated with increased morbidity or mortality.

The Changes of Elongation Index of erythrocytes caused by storage of blood at low temperature

Introduction: An important parameter characterizing the ability of erythrocytes to deform depending on the blood flow conditions is the Elongation Index (EI), and it is a parameter defined by the shape of the erythrocyte obtained as a diffraction pattern of erythrocytes at different values of shear stresses.

Material and methods: EI measurements at different shear stress were performed by Laser-assisted Optical Rotational Cell Analyzer (LORRCA) for erythrocytes derived from Tissue Bank in Katowice. Measurements were performed immediately after receiving them from Tissue Bank and after 2, 9, and 28 days of storage of samples at the temperature of 4°C in solution with the anticoagulant.

Results: An increase in the erythrocytes Elongation Index in the first 9 days of storing samples at low temperatures was observed in the entire range of applied shear stresses. This indicates an increase in the elasticity of erythrocytes during short-term storage at 4°C. In turn, on the 28th day of erythrocyte storage, a significant decrease in the Elongation Index for shear stresses greater than 1 Pa was observed, which indicates the stiffening of the erythrocyte membrane structure, reducing their elasticity. The relative decrease in the Elongation Index of erythrocytes stored for 28 days compared to erythrocytes measured at the beginning was similar and slightly greater than 30% for shear stresses greater than 3 Pa. For shear stresses lower than 3 Pa, the relative change in elongation index was smaller than for shear stresses greater than 3 Pa and increased with the increase in shear stress.

Conclusions: The elongation index of erythrocytes stored in the anticoagulant solution at 4°C, initially increases in the entire range of applied shear stresses in the first few days from the moment of blood collection and preparation at the Tissue Bank, and then decreases, but on the ninth day of storage the elongation index is still higher than for blood immediately after collection.

Extracorporeal life support system during cardiovascular procedures: Insights from the German Lifebridge registry

The frequency of mechanical circulatory support (MCS) device application has increased in recent years. Besides implantation in the emergency setting, such as circulatory arrest, MCS is also increasingly used electively to ensure hemodynamic stability in high-risk patients, for example, during percutaneous coronary interventions (PCI), valve interventions or off-pump coronary bypass surgery. Lifebridge (Zoll Medical GmbH, Germany) is a compact percutaneous MCS device widely used in daily clinical routine. The present study aimed to investigate the indications, feasibility, and outcomes after use of Lifebridge in cardiac interventions, evaluating a large-scale multicenter database. A total of 60 tertiary cardiovascular centers were questioned regarding application and short-term outcomes after the use of the Lifebridge system (n = 160 patients). Out of these 60 centers, eight consented to participate in the study (n = 39 patients), where detailed data were collected using standardized questionnaires. Demographic and clinical characteristics of the patient population, procedural as well as follow-up data were recorded and analyzed. In 60 interrogated centers, Lifebridge was used in 74% of emergency cases and 26% in the setting of planned interventions. The subcohort interrogated in detail displayed the same distribution of application scenarios, while the main cardiovascular procedure was high-risk PCI (82%). All patients were successfully weaned from the device and 92% (n = 36) of the patients studied in detail survived after 30 days. As assessed 30 days after insertion of the device, bleeding requiring red blood cell (RBC) transfusion constituted the main complication, occurring in 49% of cases. In our analysis of clinical data, the use of Lifebridge in cardiac intervention was shown to be feasible. Further prospective studies are warranted to identify patients who benefit from hemodynamic MCS support despite the increased rate of RBC transfusion due to challenges in access sites during cardiovascular procedures.

Red blood cell storage duration and long-term mortality in patients undergoing cardiac intervention: a Danish register study

OBJECTIVES

To study the effect of red blood cell (RBC) storage duration on long-term mortality in patients undergoing cardiac intervention.

BACKGROUND

RBCs undergo numerous structural and functional changes during storage. Observational studies have assessed the association between RBC storage duration and patient outcomes with conflicting results.

METHODS

Between January 2006 and December 2014, 82 408 patients underwent coronary angiography. Of these, 1856 patients received one to four RBC units within 30 days after this procedure. Patients were allocated according to length of RBC storage duration: short-term (≤11 days), intermediate (IM)-term (12-23 days) and long-term (≥24 days). The study endpoints were 30-day and long-term all-cause mortality.

RESULTS

A total of 4168 RBC units were given to 1856 patients. The mean RBC storage duration was 8.5 ± 2.1, 17.7 ± 3.4 and 29.9 ± 3.4 days in the short-term, IM-term and long-term storage groups, respectively. There was no difference in baseline characteristics between the groups. The long-term storage group received significantly more units (2.4 ± 1.0 units) as compared to the short-term (2.0 ± 1.0 units; P < 0.001) and IM-term storage group (2.2 ± 1.0 units; P < 0.01). In the survival analysis, there was no significant difference in all-cause mortality between the groups (log-rank: 0.509 for 30-days mortality; 0.493 for 5-year mortality). Additional stratified analysis demonstrated no association between RBC storage duration and long-term mortality.

CONCLUSION

This study did not find an association between RBC storage duration and 30-days or long-term mortality in patients undergoing cardiac intervention.

Mortality outcomes in patients transfused with fresher versus older red blood cells: a meta-analysis

BACKGROUND

Among transfused patients, the effect of the duration of red blood cell storage on mortality remains unclear. This study aims to compare the mortality of patients who were transfused with fresher versus older red blood cells.

METHODS

We performed an updated systematic search in the CENTRAL, MEDLINE, EMBASE and CINAHL databases, from January 2015 to October 2016. RCTs of hospitalized patients of any age comparing transfusion of fresher versus older red blood cells were eligible. We used a random-effects model to calculate pooled risk ratios (RRs) with corresponding 95% confidence interval (CI).

RESULTS

We identified 14 randomized trials that enrolled 26 374 participants. All-cause mortality occurred in 1219 of 9531 (12·8%) patients who received a transfusion of fresher red blood cells and 1810 of 16 843 (10·7%) in those who received older red blood cells (RR: 1·04, 95% CI: 0·98-1·12, P = 0·90, I² = 0%, high certainty for ruling out benefit of fresh blood, moderate certainty for ruling out harm of fresh blood). In six studies, in-hospital death occurred in 691 of 7479 (9·2%) patients receiving fresher red cells and 1291 of 14 757 (8·8%) receiving older red cells (RR: 1·06, 95% CI: 0·97-1·15, P = 0·81, I² = 0%, high certainty for ruling out benefit of fresh blood, moderate certainty for ruling out harm of fresh blood).

CONCLUSION

Transfusion of fresher red blood cells does not reduce overall or in-hospital mortality when compared with older red blood cells. Our results support the practice of transfusing patients with the oldest red blood cells available in the blood bank.

Multiphoton excited hemoglobin fluorescence and third harmonic generation for non-invasive microscopy of stored blood

Red blood cells (RBC) in two-photon excited fluorescence (TPEF) microscopy usually appear as dark disks because of their low fluorescent signal. Here we use 15fs 800nm pulses for TPEF, 45fs 1060nm pulses for three-photon excited fluorescence, and third harmonic generation (THG) imaging. We find sufficient fluorescent signal that we attribute to hemoglobin fluorescence after comparing time and wavelength resolved spectra of other expected RBC endogenous fluorophores: NADH, FAD, biliverdin, and bilirubin. We find that both TPEF and THG microscopy can be used to examine erythrocyte morphology non-invasively without breaching a blood storage bag.

Use of propensity score methods to address adverse events associated with the storage time of blood in an obstetric population: a comparison of methods

Background

A recent topic of interest in the blood transfusion literature is the existence of adverse effects of transfusing red cells towards the end of their storage life. This interest has been sparked by conflicting results in observational studies, however a number of methodological difficulties with these studies have been noted. One potential strategy to address these difficulties is the use of propensity scores, of which there are a number of possible methods. This study aims to compare the traditional methods for binary exposures with more recently developed generalised propensity score methods.

Methods

Data were obtained from probabilistically linked hospital, births and blood bank databases for all women giving birth from 23 weeks gestation in New South Wales, Australia, between July 2006 and December 2010 with complete information on the birth admission and blood issued. Analysis was restricted to women who received 1–4 units of red cells. Three different propensity score methods (for binary, ordinal and continuous exposures) were compared, using each of four different approaches to estimating the effect (matching, stratifying, weighting and adjusting by the propensity score). Each method was used to determine the effect of blood storage time on rates of severe morbidity and readmission or transfer.

Results

Data were available for 2990 deliveries to women receiving 1–4 units of red cells. The rate of severe maternal morbidity was 3.7 %, and of readmission or transfer was 14.4 %. There was no association between blood storage time and rates of severe morbidity or readmission irrespective of the approach used. There was no single optimal propensity score method; the approaches differed in their ease of implementation and interpretation.

Conclusions

Within an obstetric population, there was no evidence of an increase in adverse events following transfusion of older blood. Propensity score methods provide a useful tool for addressing the question of adverse events with increasing storage time of blood, as these methods avoid many of the pitfalls of previous studies. In particular, generalised propensity scores can be used in situations where the exposure is not binary.

Impact of institutional culture on rates of transfusions during cardiovascular procedures: The Michigan experience

BACKGROUND

Red blood cell (RBC) transfusions have been associated with morbidity and mortality in both coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCI). As a mechanism for identifying determinants of RBC practice, we quantified the relationship between a center's PCI and CABG transfusion rate.

METHODS

We identified all patients undergoing CABG (n = 16,568) or PCI (n = 94,634) at each of 33 centers from 2010 through 2012 in the state of Michigan and compared perioperative RBC transfusion rates for CABG and PCI at each center. Crude and adjusted transfusion rates were modeled separately. We adjusted for common preprocedural risk factors (12 for CABG and 23 for PCI) and reported Pearson correlation coefficients based on the crude and risk-adjusted rates.

RESULTS

As expected, RBC transfusion was more common after CABG (mean 46.5%) than PCI (mean 3.3%), with wide variation across centers for both (CABG min:max 26.5:71.3, PCI min:max 1.6:6.0). However, RBC transfusion rates were significantly correlated between CABG and PCI in both crude, 0.48 (P = .005), and adjusted, 0.53 (P = .001), analyses. These findings were consistent when restricting to nonemergent cases (radj = 0.44, P = .001).

CONCLUSIONS

Red blood cell transfusion rates were significantly correlated between the CABG and PCI at individual hospitals in Michigan, independent of patient case mix. Future work should explore institutional practice patterns, philosophies, and guidelines for RBC transfusions.

Transfusion of recently donated (fresh) red blood cells (RBCs) does not improve survival in comparison with current practice, while safety of the oldest stored units is yet to be established: a meta-analysis

BACKGROUND AND OBJECTIVES

Preclinical studies generated the hypothesis that older stored red blood cells (RBCs) can increase transfusion risks. To examine the most updated and complete clinical evidence and compare results between two trial designs, we assessed both observational studies and randomized controlled trials (RCTs) studying the effect of RBC storage age on mortality.

MATERIALS AND METHODS

Five databases were searched through December 2014 for studies comparing mortality using transfused RBCs having longer and shorter storage times.

RESULTS

Analysis of six RCTs found no significant differences in survival comparing current practice (average storage age of 2 to 3 weeks) to transfusion of 1- to 10-day-old RBCs (OR 0·91, 95% CI 0·77-1·07). RBC storage age was lower in RCTs vs. observational studies (P = 0·01). The 31 observational studies found an increased risk of death (OR 1·13, 95% CI 1·03-1·24) (P = 0·01) with increasing age of RBCs, a different mortality effect than RCTs (P = 0·02).

CONCLUSION

RCTs established that transfusion of 1- to 10-day-old stored RBCs is not superior to current practice. The apparent discrepancy in mortality between analyses of RCTs and observational studies may in part relate to differences in hypotheses tested and ages of stored RBCs studied. Further trials investigating 1- to 10-day-old stored RBC benefits would seem of lower priority than studies to determine whether 4- to 6-week stored units have safety and efficacy equivalent to the 2- to 3-week-old stored RBCs commonly transfused today.

Storage duration of transfused red blood cells is not significantly associated with postoperative adverse events in pediatric cardiac surgery patients

The aim of this study was to evaluate the association of storage duration of transfused red blood cells with the risk of postoperative serious adverse events in pediatric cardiac surgery patients. We studied 517 patients and found that 22 patients (4.3%) had at least one serious adverse event. The maximum and mean storage duration of transfused red blood cells did not differ significantly between patients with and without serious adverse events (maximum, p = 0.89; mean, p = 0.81). In our study of pediatric cardiac surgery patients, the storage duration of transfused red blood cells was not significantly associated with the risk of serious adverse events.

Identified metabolic signature for assessing red blood cell unit quality is associated with endothelial damage markers and clinical outcomes

BACKGROUND

There has been interest in determining whether older red blood cell (RBC) units have negative clinical effects. Numerous observational studies have shown that older RBC units are an independent factor for patient mortality. However, recently published randomized clinical trials have shown no difference of clinical outcome for patients receiving old or fresh RBCs. An overlooked but essential issue in assessing RBC unit quality and ultimately designing the necessary clinical trials is a metric for what constitutes an old or fresh RBC unit.

STUDY DESIGN AND METHODS

Twenty RBC units were profiled using quantitative metabolomics over 42 days of storage in SAGM with 3- to 4-day time intervals. Metabolic pathway usage during storage was assessed using systems biology methods. The detected time intervals of the metabolic states were compared to clinical outcomes.

RESULTS

Using multivariate statistics, we identified a nonlinear decay process exhibiting three distinct metabolic states (Days 0-10, 10-17, and 17-42). Hematologic variables traditionally measured in the transfusion setting (e.g., pH, hemolysis, RBC indices) did not distinguish these three states. Systemic changes in pathway usage occurred between the three states, with key pathways changing in both magnitude and direction. Finally, an association was found between the time periods of the metabolic states with the clinical outcomes of more than 280,000 patients in the country of Denmark transfused over the past 15 years and endothelial damage markers in healthy volunteers undergoing autologous transfusions.

CONCLUSION

The state of RBC metabolism may be a better indicator of cellular quality than traditional hematologic variables.

Impact of the age of stored blood on trauma patient mortality: a systematic review

BACKGROUND

The impact of the age of stored red blood cells on mortality in patients sustaining traumatic injuries requiring transfusion of blood products is unknown. The objective of this systematic review was to identify and describe the available literature on the use of older versus newer blood in trauma patient populations.

METHODS

We searched PubMed, Embase, Lilac and the Cochrane Database for published studies comparing the transfusion of newer versus older red blood cells in adult patients sustaining traumatic injuries. Studies included for review reported on trauma patients receiving transfusions of packed red blood cells, identified the age of stored blood that was transfused and reported patient mortality as an end point. We extracted data using a standardized form and assessed study quality using the Newcastle-Ottawa Scale.

RESULTS

Seven studies were identified (6780 patients) from 3936 initial search results. Four studies reported that transfusion of older blood was independently associated with increased mortality in trauma patients, while 3 studies did not observe any increase in patient mortality with the use of older versus newer blood. Three studies associated the transfusion of older blood with adverse patient outcomes, including longer stay in the intensive care unit, complicated sepsis, pneumonia and renal dysfunction. Studies varied considerably in design, volumes of blood transfused and definitions applied for old and new blood..

CONCLUSION

The impact of the age of stored packed red blood cells on mortality in trauma patients is inconclusive. Future investigations are warranted.

Quantitative investigation of red blood cell three-dimensional geometric and chemical changes in the storage lesion using digital holographic microscopy

Quantitative phase information obtained by digital holographic microscopy (DHM) can provide new insight into the functions and morphology of single red blood cells (RBCs). Since the functionality of a RBC is related to its three-dimensional (3-D) shape, quantitative 3-D geometric changes induced by storage time can help hematologists realize its optimal functionality period. We quantitatively investigate RBC 3-D geometric changes in the storage lesion using DHM. Our experimental results show that the substantial geometric transformation of the biconcave-shaped RBCs to the spherocyte occurs due to RBC storage lesion. This transformation leads to progressive loss of cell surface area, surface-to-volume ratio, and functionality of RBCs. Furthermore, our quantitative analysis shows that there are significant correlations between chemical and morphological properties of RBCs.

Clinical effects of red blood cell storage

BACKGROUND

Well-characterized biochemical, structural, and physiological changes occur when red blood cells (RBCs) are stored for a period of time and are collectively called the storage lesion.

METHODS

Key study results are summarized and contrasted and new data from recently completed randomized controlled trials will be discussed.

RESULTS

It is unclear whether in vitro changes to RBCs that occur during storage are clinically relevant. The clinical effects of RBC storage have been the focus of observational studies in recent years. However, these studies lack any consensus, possibly because of methodological limitations.

CONCLUSIONS

The clinical significance of storing RBCs is controversial, although new data from randomized controlled trials of neonates and patients undergoing cardiac surgery suggest that the duration of RBC storage is not associated with adverse clinical outcomes in these patient populations.

Age of blood and adverse outcomes in a maternity population

BACKGROUND

In recent times there has been debate around whether longer storage time of blood is associated with increased rates of adverse outcomes after transfusion. It is unclear whether results focused on cardiac or critically ill patients apply to a maternity population. This study investigates whether older blood is associated with increased morbidity and readmission in women undergoing obstetric transfusion.

STUDY DESIGN AND METHODS

Women giving birth in hospitals in New South Wales, Australia, between July 2006 and December 2010 were included in the study population if they had received between 1 and 4 red blood cell units during the birth admission. Information on women's characteristics, transfusions, and outcomes were obtained from five routinely collected data sets including blood collection, birth, and hospitalization data. Generalized propensity score methods were used to determine the effect of age of blood on rates of severe morbidity and readmission, independent of confounding factors.

RESULTS

Transfusion data were available for 2990 women, with a median age of blood transfused of 20 days (interquartile range, 14-27 days). There were no differences in the maximum age of blood transfused between women with and without severe morbidity (21 [14-28] days vs. 22 [15-30] days) and in women readmitted or not (22 [14-28] days vs. 22 [16-30] days). After potential confounding factors were considered, no relationship was found between the age of blood transfused and rates of severe morbidity and readmission.

CONCLUSION

Among women receiving low-volume transfusions during a birth admission, there was no evidence of increased rates of adverse outcomes after transfusion with older blood.

Longer RBC storage duration is associated with increased postoperative infections in pediatric cardiac surgery

OBJECTIVES

Infants and children undergoing open heart surgery routinely require multiple RBC transfusions. Children receiving greater numbers of RBC transfusions have increased postoperative complications and mortality. Longer RBC storage age is also associated with increased morbidity and mortality in critically ill children. Whether the association of increased transfusions and worse outcomes can be ameliorated by use of fresh RBCs in pediatric cardiac surgery for congenital heart disease is unknown.

INTERVENTIONS

One hundred and twenty-eight consecutively transfused children undergoing repair or palliation of congenital heart disease with cardiopulmonary bypass who were participating in a randomized trial of washed versus standard RBC transfusions were evaluated for an association of RBC storage age and clinical outcomes. To avoid confounding with dose of transfusions and timing of infection versus timing of transfusion, a subgroup analysis of patients only transfused 1-2 units on the day of surgery was performed.

MEASUREMENTS AND MAIN RESULTS

Mortality was low (4.9%) with no association between RBC storage duration and survival. The postoperative infection rate was significantly higher in children receiving the oldest blood (25-38 d) compared with those receiving the freshest RBCs (7-15 d) (34% vs 7%; p = 0.004). Subgroup analysis of subjects receiving only 1-2 RBC transfusions on the day of surgery (n = 74) also demonstrates a greater prevalence of infections in subjects receiving the oldest RBC units (0/33 [0%] with 7- to 15-day storage; 1/21 [5%] with 16- to 24-day storage; and 4/20 [20%] with 25- to 38-day storage; p = 0.01). In multivariate analysis, RBC storage age and corticosteroid administration were the only predictors of postoperative infection. Washing the oldest RBCs (> 27 d) was associated with a higher infection rate and increased morbidity compared with unwashed RBCs.

DISCUSSION

Longer RBC storage duration was associated with increased postoperative nosocomial infections. This association may be secondary in part, to the large doses of stored RBCs transfused, from single-donor units. Washing the oldest RBCs was associated with increased morbidity, possibly from increased destruction of older, more fragile erythrocytes incurred by washing procedures. Additional studies examining the effect of RBC storage age on postoperative infection rate in pediatric cardiac surgery are warranted.

Blood transfusion after percutaneous coronary intervention and risk of subsequent adverse outcomes: a systematic review and meta-analysis

OBJECTIVES

This study sought to define the prevalence and prognostic impact of blood transfusions in contemporary percutaneous coronary intervention (PCI) practice.

BACKGROUND

Although the presence of anemia is associated with adverse outcomes in patients undergoing PCI, the optimal use of blood products in patients undergoing PCI remains controversial.

METHODS

A search of EMBASE and MEDLINE was conducted to identify PCI studies that evaluated blood transfusions and their association with major adverse cardiac events (MACE) and mortality. Two independent reviewers screened the studies for inclusion, and data were extracted from relevant studies. Random effects meta-analysis was used to estimate the risk of adverse outcomes with blood transfusions. Statistical heterogeneity was assessed by considering the I(2) statistic.

RESULTS

Nineteen studies that included 2,258,711 patients with more than 54,000 transfusion events were identified (prevalence of blood transfusion 2.3%). Crude mortality rate was 6,435 of 50,979 (12.6%, 8 studies) in patients who received a blood transfusion and 27,061 of 2,266,111 (1.2%, 8 studies) in the remaining patients. Crude MACE rates were 17.4% (8,439 of 48,518) in patients who had a blood transfusion and 3.1% (68,062 of 2,212,730) in the remaining cohort. Meta-analysis demonstrated that blood transfusion was independently associated with an increase in mortality (odds ratio: 3.02, 95% confidence interval: 2.16 to 4.21, I(2) = 91%) and MACE (odds ratio: 3.15, 95% confidence interval: 2.59 to 3.82, I(2) = 81%). Similar observations were recorded in studies that adjusted for baseline hematocrit, anemia, and bleeding.

CONCLUSIONS

Blood transfusion is independently associated with increased risk of mortality and MACE events. Clinicians should minimize the risk for periprocedural transfusion by using available bleeding-avoidance strategies and avoiding liberal transfusion practices.

The pathophysiology and consequences of red blood cell storage

Red cell transfusion therapy is a common treatment modality in contemporary medical practice. Although blood collection and administration is safer and more efficient than ever before, red cells undergo multiple metabolic and structural changes during storage that may compromise their functionality and viability following transfusion. The clinical relevance of these changes is a hotly debated topic that continues to be a matter of intense investigation. In the current review, we begin with an in-depth overview of the pathophysiological mechanisms underlying red cell storage, with a focus on altered metabolism, oxidative stress and red cell membrane damage. We proceed to review the current state of evidence on the clinical relevance and consequences of the red cell storage lesion, while discussing the strengths and limitations of clinical studies.

Transfusion of stored red blood cells in trauma patients is not associated with increased procoagulant microparticles

BACKGROUND

We set out to determine the effects of transfusing stored red blood cells (RBCs) on the levels of procoagulant microparticles (MPs) in the blood of trauma patients.

METHODS

Blood was drawn and processed to platelet poor plasma for MP analysis for 409 injured patients seen in the trauma bay from February 2011 to January 2013. Blood from 27 noninjured volunteers was also analyzed. Quantification of total procoagulant MP (per microliter plasma) using a direct plasma analysis via flow cytometry was performed. Demographic data, Injury Severity Score (ISS), overall mortality, and units of transfused packed RBCs were collected. Data are presented as median (interquartile range [IQR]). Transfusion groups were assessed using t test or Wilcoxon rank-sum test as appropriate. The α level was set as 0.05 for statistical significance.

RESULTS

Median ISS was 12 (IQR, 5-19), 12% were transfused, median age was 48 years (IQR, 29-62 years), 68% were male, and overall mortality was 3%. Median units transfused were 3 (IQR, 2-5). The median number of all procoagulant MP was greater in trauma patients (median 758; IQR, 405-1,627) when compared with our control subjects (median, 232; IQR, 125-372; p < 0.0001). This difference remained significant after adjusting for age and sex (p < 0.0001). In 39 patients who had MP levels measured before transfusion with RBC, the procoagulant MP levels did not change after transfusion (p = 0.07). Patients transfused with RBCs that were 14 days or older did not have increased procoagulant MP levels when compared with those that received RBCs that were younger than 14 days (p = 0.5).This was also true for those who received RBCs that were 28 days or older when compared with those that received RBCs that were younger than 28 days (p = 0.84).

CONCLUSION

Procoagulant MP is significantly greater in trauma patients as compared with volunteers, even after adjusting for age and sex. We did not observe any change in the levels of procoagulant MPs after transfusion of stored RBCs.

LEVEL OF EVIDENCE

Epidemiologic/prognostic study, level III.

Does prolonged storage of red blood cells cause harm?

Red blood cells (RBCs) degrade progressively during the weeks of refrigerated storage. No universally accepted definition of 'fresh' or 'old' RBCs exists. While practices vary from country to country, preservative solutions permitting shelf life as long as 7 weeks have been licenced. Transfusion of stored RBCs, particularly those at the end of the approved shelf life, has been implicated in adverse clinical outcomes. The results of observational analyses, animal models and studies in volunteers have proved provocative, controversial and contradictory. A recently completed randomized controlled trial (RCT) in premature infants exemplifies the difficulties with moderately sized clinical studies. Several other RCTs are in progress. The effect of RBC storage may well vary according to the clinical setting. Resolution of the importance of the storage lesion may require large pragmatic clinical trials. In the meantime, institutions involved in blood collection and transfusion should explore strategies that assure blood availability, while limiting the use of the oldest RBCs currently approved by regulation.

Duration of red blood cells storage and outcome in critically ill patients

PURPOSE

There is conflicting evidence on the effect of red blood cells (RBC) storage duration and clinical outcomes. We aimed to investigate the association between RBC storage duration and clinical outcomes in patients admitted to the intensive care unit (ICU).

MATERIALS AND METHODS

We retrospectively (2001-2011) studied adults admitted to the ICUs of 2 hospitals who received RBC. Using the mean, maximum and minimum age of RBC units transfused, we evaluated the association between RBC storage duration and mortality. We also analyzed the association between mean age of RBC units and length of stay (LOS) in survivors. We performed sensitivity analyses in patients who only received RBC in ICU and who only received leukodepleted RBC.

RESULTS

We studied 8416 patients who received a median of 4 (interquartile range, 2-7) RBC units. After multivariate analysis, age of RBC was not independently associated with mortality, including in the subgroup analyses. Furthermore, there was no clinically relevant relationship between mean RBC age and LOS.

CONCLUSIONS

RBC storage duration was not associated with increased mortality nor ICU and hospital LOS. These results support the view that the effect of RBC storage duration on outcomes in critically ill patients is uncertain.

Transfusion of older red blood cells is associated with decreased graft survival after orthotopic liver transplantation

Investigations have demonstrated conflicting results regarding the influence of the red blood cell (RBC) storage duration on outcomes. We evaluated whether graft failure or mortality after orthotopic liver transplantation (OLT) increased when recipients were transfused with older RBCs. This study included 637 patients who underwent OLT between January 2001 and June 2011. Baseline and perioperative data were obtained from our blood bank, the Unified Transplant Center database, and the United Network for Organ Sharing database. Recipients whose transfused RBCs were all stored for ≤ 15 days were grouped in a younger group, and recipients who were transfused with RBCs stored for >15 days were placed in an older group. The relationship between graft survival/mortality and the age of intraoperatively transfused RBCs was studied by Kaplan-Meier estimation with a log-rank test and multivariate Cox proportional hazards regression. Three hundred thirty-four patients and 303 patients were grouped in the younger and the older RBC groups, respectively, on the basis of the ages of intraoperatively transfused RBCs. Kaplan-Meier estimates of graft survival/mortality as a function of the posttransplant time were significantly different: the older group experienced the outcome sooner than the younger group [P = 0.02 (log-rank test)]. After covariate adjustments, the risk of graft failure/mortality was significantly different at any given time after transplantation between patients receiving intraoperative transfusions of older RBC units and patients receiving intraoperative transfusions of younger RBC units (hazard ratio = 1.65, 95% confidence interval = 1.18-2.31). In conclusion, patients who received intraoperative transfusions of RBCs with longer storage times had an increased risk of adverse outcomes.

Red blood cell storage: how long is too long?

Red blood cells (RBCs) undergo biochemical and structural changes during storage, commonly referred to as the "storage lesion." Evidence suggests that the longer the RBC product is stored, the less effective is the transfused blood. Many studies linking morbidity to transfusion have not considered duration of RBC storage as a variable that may modulate the effect. In addition, the effects of supply and demand and RBC inventory management strategies have been incompletely investigated. It is possible to envision a blood management system based on modern inventory management strategies that could greatly reduce storage duration.

The impact of prolonged storage of red blood cells on cancer survival

Background

The duration of storage of transfused red blood cells (RBC) has been associated with poor clinical outcomes in some studies. We sought to establish whether prolonged storage of transfused RBC in cancer patients influences overall survival (OS) or cancer recurrence.

Methods and Findings

Patients diagnosed with cancer at The Ottawa Regional Cancer Centre between January 01, 2000 and December 31, 2005 were included (n = 27,591) where 1,929 (7.0%) received RBC transfusions within one year from diagnosis. Transfused RBC units were categorized as “new” if stored for less than 14 days, “intermediate” if stored between 14 and 28 days and “old” if stored for more than 28 days. Baseline characteristics between the comparative groups were compared by ANOVA test. Categorical variables and continuous variables were compared using Chi-squared and Wilcoxan rank-sum tests respectively. Overall survival was not associated with duration of storage of transfused RBC with a median survival of 1.2, 1.7, 1.1 years for only new, intermediate and old RBC units respectively (p = 0.36). Cancer recurrence was significantly higher in patients who received a RBC transfusion than those who did not (56.3% vs 33.0% respectively; p<0.0001) but was not affected by the duration of storage of transfused RBC (p = 0.06). In multivariate analysis, lung cancer, advanced stage, chemotherapy, radiation, cancer-related surgery and cancer recurrence were associated with inferior OS (p<0.05), while age, advanced stage, lung cancer, and more than 6 units of blood transfused were associated with cancer recurrence (p<0.05). The duration of storage of RBC before transfusion was not associated with OS or cancer recurrence in multivariate analysis.

Conclusion

In patients diagnosed with cancer, the duration of storage of transfused RBC had no impact on OS or cancer recurrence. This suggests that our current RBC storage policy of providing RBC of variable duration of storage for patients with malignancy is safe.

Relationship between red cell storage duration and outcomes in adults receiving red cell transfusions: a systematic review

INTRODUCTION

The duration of red blood cell (RBC) storage before transfusion may alter RBC function and supernatant and, therefore, influence the incidence of complications or even mortality.

METHODS

A MEDLINE search from 1983 to December 2012 was performed to identify studies reporting age of transfused RBCs and mortality or morbidity in adult patients.

RESULTS

Fifty-five studies were identified; most were single-center (93%) and retrospective (64%), with only a few, small randomized studies (eight studies, 14.5%). The numbers of subjects included ranged from eight to 364,037. Morbidity outcomes included hospital and intensive care unit (ICU) length of stay (LOS), infections, multiple organ failure, microcirculatory alterations, cancer recurrence, thrombosis, bleeding, vasospasm after subarachnoid hemorrhage, and cognitive dysfunction. Overall, half of the studies showed no deleterious effects of aged compared to fresh blood on any endpoint. Eleven of twenty-two (50%) studies reported no increased mortality, three of nine (33%) showed no increased LOS with older RBCs and eight of twelve (66%) studies showed no increased risks of organ failure. Ten of eighteen (55%) studies showed increased infections with transfusion of older RBCs. The considerable heterogeneity among studies and numerous methodological flaws precluded a formal meta-analysis.

CONCLUSIONS

In this systematic review, we could find no definitive argument to support the superiority of fresh over older RBCs for transfusion.

Age of red blood cells and transfusion in critically ill patients

Red blood cells (RBC) storage facilitates the supply of RBC to meet the clinical demand for transfusion and to avoid wastage. However, RBC storage is associated with adverse changes in erythrocytes and their preservation medium. These changes are responsible for functional alterations and for the accumulation of potentially injurious bioreactive substances. They also may have clinically harmful effects especially in critically ill patients. The clinical consequences of storage lesions, however, remain a matter of persistent controversy. Multiple retrospective, observational, and single-center studies have reported heterogeneous and conflicting findings about the effect of blood storage duration on morbidity and/or mortality in trauma, cardiac surgery, and intensive care unit patients. Describing the details of this controversy, this review not only summarizes the current literature but also highlights the equipoise that currently exists with regard to the use of short versus current standard (extended) storage duration red cells in critically ill patients and supports the need for large, randomized, controlled trials evaluating the clinical impact of transfusing fresh (short duration of storage) versus older (extended duration of storage) red cells in critically ill patients.

Red blood cell-derived microparticles isolated from blood units initiate and propagate thrombin generation

BACKGROUND

Red blood cell-derived microparticles (RMPs) are small phospholipid vesicles shed from RBCs in blood units, where they accumulate during storage. Because microparticles are bioactive, it could be suggested that RMPs are mediators of posttransfusion complications or, on the contrary, constitute a potential hemostatic agent.

STUDY DESIGN AND METHODS

This study was performed to establish the impact on coagulation of RMPs isolated from blood units. Using calibrated automated thrombography, we investigated whether RMPs affect thrombin generation (TG) in plasma.

RESULTS

We found that RMPs were not only able to increase TG in plasma in the presence of a low exogenous tissue factor (TF) concentration, but also to initiate TG in plasma in absence of exogenous TF. TG induced by RMPs in the absence of exogenous TF was neither affected by the presence of blocking anti-TF nor by the absence of Factor (F)VII. It was significantly reduced in plasma deficient in FVIII or F IX and abolished in FII-, FV-, FX-, or FXI-deficient plasma. TG was also totally abolished when anti-XI 01A6 was added in the sample. Finally, neither Western blotting, flow cytometry, nor immunogold labeling allowed the detection of traces of TF antigen. In addition, RMPs did not comprise polyphosphate, an important modulator of coagulation.

CONCLUSIONS

Taken together, our data show that RMPs have FXI-dependent procoagulant properties and are able to initiate and propagate TG. The anionic surface of RMPs might be the site of FXI-mediated TG amplification and intrinsic tenase and prothrombinase complex assembly.

Transfusion of banked red blood cells and the effects on hemorrheology and microvascular hemodynamics in anemic hematology outpatients

BACKGROUND

The aim of this study was to investigate the effects of red blood cell (RBC) transfusion on the hemorrheologic properties and microcirculatory hemodynamics in anemic hematology outpatients receiving 2 to 4 RBC units of either "fresh" (leukoreduced storage for less than 1 week) or "aged" (leukoreduced storage for 3-4 weeks) RBCs.

STUDY DESIGN AND METHODS

Measurements were performed before and 30 minutes after RBC transfusion in hematology outpatients. Leukoreduced RBC suspensions were stored in saline-adenine-glucose-mannitol (SAGM) additive solution. Whole blood viscosity was measured using Couette low-shear viscometry, RBC deformability and aggregability were measured using laser-assisted optical rotational cell analysis, and microcirculatory density and perfusion were assessed using sidestream dark field imaging.

RESULTS

One group of patients (n = 10) received a median (interquartile range) of 3 (2-3) RBC bags that were stored for 7 (5-7) days (fresh) and the other group of patients (n = 10) received 3 (3-3) RBC bags that were stored for 23 (22-28) days (aged). After transfusion of fresh versus aged RBCs, hematocrit increased to 32 ± 3% versus 31 ± 2% (p < 0.363), whole blood viscosity increased to 4.2 ± 0.4 Pa/sec versus 4.2 ± 0.6 Pa/sec (p < 0.912), RBC deformability index remained unaffected, RBC aggregability index increased to 55 ± 10 versus 55 ± 13 (p = 0.967), microcirculatory flow remained unaffected, and microcirculatory density increased to 19.3 ± 2.5 mm/mm(2) versus 18.7 ± 1.9 mm/mm(2) (p = 0.595), respectively.

CONCLUSION

Storing leukoreduced SAGM-suspended RBCs for 3 to 4 weeks did not affect their ability to improve hemorrheologic properties and microcirculatory hemodynamics in our small group of anemic hematology outpatients. Larger studies are needed to confirm this finding.

Duration of red blood cell storage and outcomes following orthotopic liver transplantation

Liver transplantation may be complicated by massive intraoperative bleeding, and red blood cell (RBC) transfusions may be required. The storage duration or age of transfused RBCs has been shown to affect the morbidity and mortality of critically ill, trauma, and cardiac surgery patients. Here we investigate the effect of RBC age on the outcomes of liver transplant patients. Five hundred thirty-one patients underwent orthotopic liver transplantation between January 1, 2000 and August 15, 2010. The patient demographics, the Model for End-Stage Liver Disease-sodium (MELD-Na) score, and the number and age of RBC units were evaluated with univariate and multivariate models of outcomes, which included mortality rates 2 years after transplantation, postoperative infections, and organ rejection. In a univariate analysis, the number of RBC units (but not the RBC age) was associated with increased 2-year mortality, an increased risk of infection, and a decreased risk of organ rejection. Only the number of RBC units was associated with increased 2-year mortality in a multivariate Cox regression model. The mortality risk was decreased by two-thirds for patients who received <10 U of RBCs versus those who received ≥10 U (hazard ratio = 0.33, 95% confidence interval = 0.16-0.69, P = 0.003). The number of transfused RBC units was not associated with the risk of infection or organ rejection in a multivariate logistic regression model. In conclusion, the RBC age is not associated with infection, organ rejection, or death in liver transplant patients. Patients who receive more blood have an increased risk of death. In a multivariate model, the MELD-Na score was not associated with increased mortality, and this is consistent with previous studies demonstrating that the MELD-Na score is a poor predictor of long-term survival after transplantation.

Transfusion of older stored blood and risk of death: a meta-analysis

BACKGROUND

Blood for transfusion is stored for up to 42 days. Older blood develops lesions and accumulates potentially injurious substances. Some studies report increasing toxicity as blood ages. We assessed the safety of transfused older versus newer stored blood.

STUDY DESIGN AND METHODS

PubMed, Scopus, and Embase were searched using terms new and old and red blood cell and storage through May 6, 2011, for observational and randomized controlled studies comparing outcomes using transfused blood having longer and shorter storage times. Death was the outcome of interest.

RESULTS

Twenty-one studies were identified, predominantly in cardiac surgery (n=6) and trauma (n=6) patients, including 409,966 patients. A test for heterogeneity of these studies' results was not significant for mortality (I(2)=3.7%, p=0.41). Older blood was associated with a significantly increased risk of death (odds ratio, 1.16; 95% confidence interval [CI], 1.07-1.24). Using available mortality data, 97 (95% CI, 63-199) patients need to be treated with only new blood to save one life. Subgroup analysis of these trials indicated that the increased risk was not restricted to a particular type of patient, size of trial, or amount of blood transfused.

CONCLUSION

Based on available data, use of older stored blood is associated with a significantly increased risk of death.

Implications of bleeding in acute coronary syndrome and percutaneous coronary intervention

The advent of potent antiplatelet and antithrombotic agents over the past decade has resulted in significant improvement in reducing ischemic events in acute coronary syndrome (ACS). However, the use of antiplatelet and antithrombotic combination therapy, often in the settings of percutaneous coronary intervention (PCI), has led to an increase in the risk of bleeding. In patients with non-ST elevation myocardial infarction treated with antithrombotic agents, bleeding has been reported to occur in 0.4%-10% of patients, whereas in patients undergoing PCI, periprocedural bleeding occurs in 2.2%-14% of cases. Until recently, bleeding was considered an intrinsic risk of antithrombotic therapy, and efforts to reduce bleeding have received little attention. There have been increasing data demonstrating that bleeding is associated with adverse outcomes, including myocardial infarction, stroke, and death. Therefore, it is imperative to optimize patient outcomes by adopting pharmacological and nonpharmacological strategies to minimize bleeding while maximizing treatment efficacy. In this paper, we present a review of the bleeding classifications used in large-scale clinical trials in patients with ACS and those undergoing PCI treated with antiplatelets and antithrombotic agents, adverse outcomes, particularly mortality associated with bleeding complications, and suggested predictive risk factors. Potential mechanisms of the association between bleeding and mortality and strategies to reduce bleeding complications are also discussed.

Storage time of transfused red blood cells and impact on clinical outcomes in hematopoietic stem cell transplantation

BACKGROUND

Red blood cell (RBC) transfusion may prolong recovery in some patients, perhaps due to changes that occur during more prolonged RBC storage. We examined the impact of RBC transfusion and the age of transfused RBC units on clinical outcomes in hematopoietic stem cell transplantation (HSCT).

STUDY DESIGN AND METHODS

Data concerning RBC transfusions between Day 0 and Day +30 were analyzed for patients undergoing HSCT (n = 555) at a single institution. "Old" RBC units were defined as those stored for 15 days or longer.

RESULTS

The proportion of old RBC units transfused and the mean age of transfused units did not correlate with 100-day nonrelapse mortality, organ-specific toxicity, length of stay (LOS), or incidence of intensive care unit (ICU) admission (p > 0.05). In comparing the 71 patients who received only old RBC units with 218 patients who received only "new" RBC units, there was no increase in adverse clinical outcomes after HSCT. Autologous transplant recipients (n = 355, 3.8 units/patient) were more likely to avoid RBC transfusion and received fewer units compared with allogeneic recipients (n = 200, 6.4 units/patient, p < 0.0001). The mean number of transfused RBC units was greater in patients admitted to the ICU (10.5 units vs. 3.7 units/patient, p < 0.01), correlated with longer LOS (p < 0.0001), and correlated with increasing number of organ systems with toxicity of at least Grade 2 (p < 0.0001).

CONCLUSION

The importance of RBC storage time does not appear to influence clinical outcomes in HSCT. Patients with increased RBC transfusion requirements have greater toxicity after HSCT. Whether RBC transfusion contributes to toxicity, however, remains unclear.

The Age of Blood Evaluation (ABLE) randomized controlled trial: study design

Red blood cells (RBCs) are transfused to treat anemia and to maintain oxygen delivery to vital organs during critical illness. Laboratory and observational studies have raised the possibility that prolonged RBC storage may adversely affect clinical outcomes. Compared with RBCs stored less than 1 week, there are no clinical data demonstrating that RBCs stored longer remain as effective at carrying or releasing oxygen, and observational studies have risen to possibility that prolonged RBC storage might result in harm to vulnerable patients requiring blood transfusions. The "Age of Blood Evaluation" (ABLE) study (ISRCTN44878718) is a double-blind, multicenter, parallel randomized controlled clinical trial. It will test the hypothesis that the transfusion of prestorage leukoreduced RBCs stored for 7 days or less (fresh arm) as compared with standard-issue RBCs stored, on average, 15 to 20 days (control arm) will lead to lower 90-day all-cause mortality and reduced morbidity in critically ill adults. We include adults in intensive care units (ICUs) who (1) have had a request for a first RBC unit transfusion during the first 7 days of ICU admission and (2) have an anticipated requirement for ongoing invasive and noninvasive mechanical ventilation exceeding 48 hours. Enrolled patients are randomized at the time of transfusion to receive either standard-issue RBC units or RBCs stored 7 days or less issued by the local hospital transfusion service. The primary outcome is 90-day all-cause mortality. Secondary outcomes include ICU and hospital mortality, organ failure, and serious nosocomial infections. With 2510 patients, we will be able to detect a 5% absolute risk reduction (from 25% to 20%). The ABLE study is currently enrolling patients in 23 university-affiliated and community-hospital ICUs across Canada; sites in France and United Kingdom are expected to start recruitment in 2011. Regardless of the results, ABLE study will have significant implications on the duration of RBC storage. A negative trial will reassure clinicians and blood bankers regarding the effectiveness and safety of standard-issue RBCs. A positive trial will have significant implications with respect to inventory management of RBCs given to critically ill adults with a high risk of mortality and will also prompt research to better understand the RBC storage lesion in the hopes of minimizing its clinical consequences through the development of better storage methods.

[Clinical impact of length of storage before red blood cell transfusion]

Presently, red blood cell units are stored up to 42 days in France and Canada. Length of storage of red blood cell units is not based on clinical outcomes: it is rather based on a decision made by some experts in the 1940s that red blood cell units can be stored as long as the average hemolysis is lower than 1% and the proportion of red blood cells still alive 24 hours post-transfusion is higher than 70%. Data reported recently suggest that transfusion with older red blood cell units may jeopardize the outcome of severely ill patients. In this paper, we comment the data already published on this question, and we summarize the randomized clinical trials presently on-going that were undertaken to address the relationship between length of storage of red blood cell units and outcomes of transfused patients.

Microparticles in stored red blood cells as potential mediators of transfusion complications

This article reviews evidence for the involvement of cell-derived microparticles (MPs) in transfusion-related adverse events. The controversy concerning possible added risk of older versus fresher stored blood is also reviewed and is consistent with the hypothesis that MPs are involved with adverse events. Although all types of circulating MPs are discussed, the emphasis is on red blood cell-derived MPs (RMPs). The evidence is particularly strong for involvement of RMPs in transfusion-related acute lung injury, but also for postoperative thrombosis. However, this evidence is largely circumstantial. Work in progress to directly test the hypothesis is also briefly reviewed.