Increased Risk of Infection and Mortality in Women after Cardiac Surgery Related to Allogeneic Blood Transfusion

Performance of a novel risk model for deep sternal wound infection after coronary artery bypass grafting

Clinical prediction models for deep sternal wound infections (DSWI) after coronary artery bypass graft (CABG) surgery exist, although they have a poor impact in external validation studies. We developed and validated a new predictive model for 30-day DSWI after CABG (REPINF) and compared it with the Society of Thoracic Surgeons model (STS). The REPINF model was created through a multicenter cohort of adults undergoing CABG surgery (REPLICCAR II Study) database, using least absolute shrinkage and selection operator (LASSO) logistic regression, internally and externally validated comparing discrimination, calibration in-the-large (CL), net reclassification improvement (NRI) and integrated discrimination improvement (IDI), trained between the new model and the STS PredDeep, a validated model for DSWI after cardiac surgery. In the validation data, c-index = 0.83 (95% CI 0.72–0.95). Compared to the STS PredDeep, predictions improved by 6.5% (IDI). However, both STS and REPINF had limited calibration. Different populations require independent scoring systems to achieve the best predictive effect. The external validation of REPINF across multiple centers is an important quality improvement tool to generalize the model and to guide healthcare professionals in the prevention of DSWI after CABG surgery.

Non-White Race/Ethnicity and Female Sex Are Associated with Increased Allogeneic Red Blood Cell Transfusion in Cardiac Surgery Patients: 2007-2018

OBJECTIVE

To evaluate racial and/or ethnic and sex disparities in allogeneic and autologous red blood cell (RBC) transfusions in cardiac surgery.

DESIGN

A retrospective observational study.

SETTING

2007 to 2018 data from FL, MD, KY, WA, NY, and CA from the State Inpatient Databases (SID), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

PARTICIPANTS

A total of 710,296 inpatients who underwent elective or emergency coronary artery bypass grafting (CABG), cardiac valve surgery,or combination CABG and/or valve surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were cohorted by race and/or ethnicity and sex, as defined by SID-HCUP. Demographic characteristics and comorbidities were compared. Rates and risk-adjusted odds ratios (aOR) were calculated for allogeneic and autologous RBC transfusion (primary outcomes). Additional secondary analyses were conducted for in-hospital mortality, 30-day readmission, 90-day readmission, hospital length of stay, and total charges to examine the effect of RBC transfusion status. Effect modification between race and sex was assessed. When controlling for patient demographics, comorbidities, and hospital characteristics, non-White patients were more likely to receive an allogeneic RBC transfusion during cardiac surgery than White patients (Black: aOR 1.17, 99% CI 1.13-1.20, p < 0.001, Hispanic: aOR 1.22, 99% CI 1.19-1.22, p < 0.001). Women were more likely to receive allogeneic RBC than men (aOR 1.69, 99% CI 1.66-1.72, p < 0.001). In interaction models, non-White women had the highest odds of allogeneic blood transfusion as compared to White men (reference category; Black women: aOR 2.04, 99% CI 1.91-2.17, p < 0.001, Hispanic women: aOR 2.03, 99% CI 1.90-2.16, p < 0.001).

CONCLUSION

These findings highlighted the differences in the rates of allogeneic RBC transfusion for non-White and female patients undergoing cardiac surgery, which is a well-established marker of poorer outcomes.

Challenges in Patient Blood Management for Cardiac Surgery: A Narrative Review

About 15 years ago, Patient Blood Management (PBM) emerged as a new paradigm in perioperative medicine and rapidly found support of all major medical societies and government bodies. Blood products are precious, scarce and expensive and their use is frequently associated with adverse short- and long-term outcomes. Recommendations and guidelines on the topic are published in an increasing rate. The concept aims at using an evidence-based approach to rationalize transfusion practices by optimizing the patient's red blood cell mass in the pre-, intra- and postoperative periods. However, elegant as a concept, the implementation of a PBM program on an institutional level or even in a single surgical discipline like cardiac surgery, can be easier said than done. Many barriers, such as dogmatic ideas, logistics and lack of support from the medical and administrative departments need to be overcome and each center must find solutions to their specific problems. In this paper we present a narrative overview of the challenges and updated recommendations for the implementation of a PBM program in cardiac surgery.

Predictors and Outcomes of Coronary Artery Bypass Grafting: A Systematic and Untargeted Analysis of More Than 120,000 Individuals and 1,300 Disease Traits

OBJECTIVE

To perform an untargeted data-driven analysis on the correlates and outcomes of coronary artery bypass grafting (CABG).

DESIGN

FinnGen cohort study.

SETTING

The authors collected information on up to 1,327 disease traits before and after CABG from nationwide healthcare registers.

PARTICIPANTS

A mixed population and patient sample of 127,911 individuals including 3,784 CABG patients.

INTERVENTIONS

The authors assessed the association between (1) traits and incident CABG and (2) CABG and incident traits using multivariate-adjusted Cox models.

MAIN RESULTS

Patients who underwent CABG and were in the fourth quartile of a risk score based on the top predictors of mortality had 12.2-fold increased risk of dying (95% confidence interval [CI], 10.3-14.5) compared with those in the first quartile. Cardiovascular disease (CVD) and CVD risk factors were most strongly associated with incident CABG. However, CABG was associated with death due to cardiac causes (hazard ratio [HR], 3.7; 95% CI, 3.5-4.0) or other causes (HR, 2.5; 95% CI, 2.4-2.7). CABG also was related to increased risk of several non-CVD traits, including anemia (HR, 3.4; 95% CI, 2.8-4.1), gastrointestinal disorders (HR, 2.2; 95% CI, 1.8-2.6), acute renal failure (HR, 4.2; 95% CI, 3.5-5.1), septicemia (HR, 3.6; 95% CI, 3.1-4.1), lung cancer (HR, 2.3; 95% CI, 1.9-2.8), Alzheimer's disease (HR, 2.5; 95% CI, 2.2-2.7), and chronic obstuctive pulmonary disease (HR, 2.5; 95% CI, 2.2-2.9).

CONCLUSIONS

Known CVD risk factors associate most strongly with incident CABG. However, CABG is associated with increased risk of several, somewhat unexpected, non-CVD traits. More detailed study of these links is warranted to establish potential causality and pathogenesis.

The effect of perioperative blood transfusion on kidney functions in total knee Arthroplasty

Objective:

Various studies have examined the effects of perioperative blood transfusion on kidney functions. In this study, we investigated the effects of blood transfusion on the kidney functions of patients undergoing total knee arthroplasty.

Methods:

: This retrospective study was carried out on 216 patients who had undergone total knee arthroplasty between January 2016 and January 2017. The patients were divided into two groups according to the level of blood transfusion used during surgery. Group-1 comprised 157 patients (72.7%) needing a blood transfusion of less than three units, while the 59 (27.3) patients in Group-2 required three or more than three units.

Results:

No statistical difference was found between the two groups regarding hypertension before surgery, diabetes mellitus, chronic kidney failure, smoking habits or lung disease (p> 0.05). Likewise, there was no significant difference related to pulmonary and other complications or mortality (p> 0.05). When the groups were compared according to their blood parameters, no statistical differences in postoperative renal or other system functions were found (p> 0.05).

Conclusions:

Blood transfusion does not have a negative effect on postoperative blood urea nitrogen (BUN) and creatinine levels, or glomerular filtration rate in total knee arthroplasty.

Adverse Outcomes of Perioperative Red Blood Cell Transfusions in Coronary Artery Bypass Grafting in Hospital Universiti Sains Malaysia

BACKGROUND

Perioperative red blood cell (RBC) transfusion in coronary artery bypass grafting (CABG) has both benefits and harms. Our aim was to study the association between perioperative RBC transfusion and its adverse outcomes.

METHODS

This was a retrospective study of patients who underwent isolated CABG in Hospital Universiti Sains Malaysia, Kelantan, Malaysia, from 1 January 2013 until 31 December 2017. Data were collected from medical records, and comparisons were made between patients who received perioperative RBC transfusions and those who did not have adverse outcomes after CABG.

RESULTS

A total of 108 patients who underwent isolated CABG were included in our study, and 78 patients received perioperative RBC transfusions. Patients who received perioperative RBC transfusions compared to those who did not were significantly more likely to develop prolonged ventilatory support (21.8% versus 0%, P = 0.003), cardiac morbidity (14.1% versus 0%, P = 0.032), renal morbidity (28.2% versus 3.3%, P = 0.005) and serious infection (20.5% versus 3.3%, P = 0.037). With each unit of packed RBC transfusions, there was a significantly increased risk of prolonged ventilatory support (adjusted odds ratio [AOR] = 1.45; 95% confidence interval [CI] = 1.20-1.77; P < 0.001), cardiac morbidity (AOR =1.40; 95%CI = 1.01-1.79; P = 0.007), renal morbidity (AOR = 1.23; 95%CI = 1.03-1.45; P = 0.019) and serious infection (AOR = 1.31; 95%CI = 1.07-1.60; P = 0.009).

CONCLUSION

Perioperative RBC transfusion in isolated CABG patients is associated with increased risks of developing adverse events such as prolonged ventilatory support, cardiac morbidity, renal morbidity and serious infection.

Association Between Adverse Clinical Outcomes After Coronary Artery Bypass Grafting and Perioperative Blood Transfusions

Background

Bleeding is a serious complication of coronary artery bypass grafting that often leads to blood transfusion. Approximately 50% of patients who have the surgery receive blood products, and blood transfusions play a role in adverse outcomes after the surgery.

Objective

To examine the association between perioperative blood transfusion and postoperative adverse outcomes in patients undergoing coronary artery bypass grafting.

Methods

A systematic review of the literature, via the matrix method of quality evaluation, was conducted. PubMed, CINAHL, and Science Direct databases for 2000 through 2016 were searched. Inclusion criteria were articles published in English and original research related to clinical outcomes of blood transfusion after coronary artery bypass grafting. Seventeen articles were included in the review.

Results

Mortality, both short- and long-term, was significantly higher in transfusion patients than in nontransfusion patients. Patients with transfusion of red blood cells had higher resource utilization and more complications, including infection, pneumonia, renal failure, graft occlusion, and atrial fibrillation, than did nontransfusion patients.

Conclusion

An association exists between red blood cell transfusions and adverse clinical outcomes for patients undergoing coronary artery bypass grafting. Transfusion of red blood cells is sometimes unnecessary, may be injurious, and should be used cautiously. Even a single-unit increase in perioperative red blood cell transfusions can have a significant adverse impact on outcomes. Individual benefits and risks should be weighed before transfusion to avoid adverse outcomes. Transfusion guidelines should be reviewed to include the latest evidence to guarantee the most appropriate use of blood products.

Gender disparities in red blood cell transfusion in elective surgery: a post hoc multicentre cohort study

OBJECTIVES

A post hoc gender comparison of transfusion-related modifiable risk factors among patients undergoing elective surgery.

SETTINGS

23 Austrian centres randomly selected and stratified by region and level of care.

PARTICIPANTS

We consecutively enrolled in total 6530 patients (3465 women and 3065 men); 1491 underwent coronary artery bypass graft (CABG) surgery, 2570 primary unilateral total hip replacement (THR) and 2469 primary unilateral total knee replacement (TKR).

MAIN OUTCOME MEASURES

Primary outcome measures were the number of allogeneic and autologous red blood cell (RBC) units transfused (postoperative day 5 included) and differences in intraoperative and postoperative transfusion rate between men and women. Secondary outcomes included perioperative blood loss in transfused and non-transfused patients, volume of RBCs transfused, perioperative haemoglobin values and circulating red blood volume on postoperative day 5.

RESULTS

In all surgical groups, the transfusion rate was significantly higher in women than in men (CABG 81 vs 49%, THR 46 vs 24% and TKR 37 vs 23%). In transfused patients, the absolute blood loss was higher among men in all surgical categories while the relative blood loss was higher among women in the CABG group (52.8 vs 47.8%) but comparable in orthopaedic surgery. The relative RBC volume transfused was significantly higher among women in all categories (CABG 40.0 vs 22.3; TKR 25.2 vs 20.2; THR 26.4 vs 20.8%). On postoperative day 5, the relative haemoglobin values and the relative circulating RBC volume were higher in women in all surgical categories.

CONCLUSIONS

The higher transfusion rate and volume in women when compared with men in elective surgery can be explained by clinicians applying the same absolute transfusion thresholds irrespective of a patient's gender. This, together with the common use of a liberal transfusion strategy, leads to further overtransfusion in women.

Observational studies - should we simply ignore them in assessing transfusion outcomes?

BACKGROUND

As defined by evidence-based medicine randomized controlled trials rank higher than observational studies in the hierarchy of clinical research. Accordingly, when assessing the effects of treatments on patient outcomes, there is a tendency to focus on the study method rather than also appraising the key elements of study design. A long-standing debate regarding findings of randomized controlled trials compared with those of observational studies, their strengths and limitations and questions regarding causal inference, has recently come into focus in relation to research assessing patient outcomes in transfusion medicine.

DISCUSSION

Observational studies are seen to have limitations that are largely avoided with randomized controlled trials, leading to the view that observational studies should not generally be used to inform practice. For example, observational studies examining patient outcomes associated with blood transfusion often present higher estimates of adverse outcomes than randomized controlled trials. Some have explained this difference as being a result of observational studies not properly adjusting for differences between patients transfused and those not transfused. However, one factor often overlooked, likely contributing to these variances between study methods is different exposure criteria. Another common to both study methods is exposure dose, specifically, measuring units transfused during only a part of the patient's hospital stay. When comparing the results of observational studies with randomized controlled trials assessing transfusion outcomes it is important that one consider not only the study method, but also the key elements of study design. Any study, regardless of its method, should focus on accurate measurement of the exposure and outcome variables of interest. Failure to do so may subject the study, regardless of its type, to bias and the need to interpret the results with caution.

Increased hospital costs associated with red blood cell transfusion

BACKGROUND

Red blood cell (RBC) transfusion is independently associated in a dose-dependent manner with increased intensive care unit stay, total hospital length of stay, and hospital-acquired complications. Since little is known of the cost of these transfusion-associated adverse outcomes our aim was to determine the total hospital cost associated with RBC transfusion and to assess any dose-dependent relationship.

STUDY DESIGN AND METHODS

A retrospective cohort study of all multiday acute care inpatients discharged from a five hospital health service in Western Australia between July 2011 and June 2012 was conducted. Main outcome measures were incidence of RBC transfusion and mean inpatient hospital costs.

RESULTS

Of 89,996 multiday, acute care inpatient discharges, 4805 (5.3%) were transfused at least 1 unit of RBCs. After potential confounders were adjusted for, the mean inpatient cost was 1.83 times higher in the transfused group compared with the nontransfused group (95% confidence interval, 1.78-1.89; p < 0.001). The estimated total hospital-associated cost of RBC transfusion in this study was AUD $77 million (US $72 million), representing 7.8% of total hospital expenditure on acute care inpatients. There was a significant dose-dependent association between the number of RBC units transfused and increased costs after adjusting for confounders.

CONCLUSION

RBC transfusions were independently associated with significantly higher hospital costs. The financial implication to hospital budgets will assist in prioritizing areas to reduce the rate of RBC transfusions and in implementing patient blood management programs.

SSRIs increase risk of blood transfusion in patients admitted for hip surgery

Background

Recent studies have shown that an increased bleeding tendency can be caused by Selective Serotonin Reuptake Inhibitors (SSRI) use. We aimed to investigate the occurrence and risk of blood transfusion in SSRI users compared to non-SSRI users in a cohort of patients admitted for hip-surgery.

Methods

We conducted a retrospective cohort study of patients who underwent planned or emergency hip surgery from 1996 to 2011 in the Academic Medical Center in Amsterdam. Primary outcome measure was risk of blood transfusion. Secondary outcome measures were pre- and postoperative hemoglobin level. Multivariate logistic regression was used to adjust for potential confounders.

Results

One-hundred and fourteen SSRI users were compared to 1773 non-SSRI users. Risk of blood transfusion during admission was increased for SSRI users in multivariate analyses (OR 1.7 [95% CI 1.1–2.5]). Also, pre-operative hemoglobin levels were lower in SSRI users (7.8±1.0 mmol/L) compared to non-SSRI users (8.0±1.0 mmol/L) (p = 0.042)), as were postoperative hemoglobin levels (6.2±1.0 mmol/L vs. 6.4±1.0 mmol/L respectively) (p = 0.017)).

Conclusions

SSRI users undergoing hip surgery have an increased risk for blood transfusion during admission, potentially explained by a lower hemoglobin level before surgery. SSRI use should be considered as a potential risk indicator for increased blood loss in patients admitted for hip surgery. These results need to be confirmed in a prospective study.

The relationship between total red blood cells and plasma transfusion and acute lung injury risk after cardiac surgery: a retrospective study

The aim of our study was to determine whether red blood cells (RBCs) and fresh frozen plasma (FFP) transfusion is independently associated with the development of acute lung injury (ALI) in patients after cardiac surgery. In retrospective study, 165 patients were included. The results showed total fresh RBCs transfusion were not significantly increased in patients who developed ALI compared with patients who did not develop ALI (4.7 ± 2.4, 4 [0-12] units VS 4.0 ± 1.9, 3 [0-9] units, P = 0.119). FFP transfusion were also not significantly increased (704.1 ± 832.5, 600 [150-6500] ml VS 533.9 ± 323.6, 400 [125-3100] ml, P = 0.053). Multivariable logistic regression analysis showed that only age and CPB time were independent factors for ALI, but not for total RBCs and FFP transfused, with the adjusted OR 0.952 (95% CI 0.762-1.189, P=0.664), and 1.000 (95% CI 0.999-1.001, P = 0.480), respectively. In subgroup analysis, female patients showed a lower ALI incidence in low RBCs transfused group (23.9% VS 45.0%, OR 0.38, 95% CI 0.15-0.98) and in low FFP transfused group (22.0% VS 44.4%, OR 0.35, 95% CI 0.14-0.90). Our study demonstrates that red blood cells and fresh-frozen plasma transfusion are not related with ALI after cardiac surgery in our institution.

Pharmacologic tools to reduce bleeding in surgery

Strategies to reduce blood loss and the need for transfusions in surgery include enhancement of coagulation, inhibition of fibrinolysis, and an improved decision algorithm for transfusion based on bedside monitoring of global hemostasis. The synthetic antifibrinolytic drug tranexamic acid has emerged as an effective alternative in this respect for orthopedic and cardiac surgery. Although it seems less effective than aprotinin, it has not been associated with the increased risk of mortality of the latter. Thromboelastography to monitor the global hemostatic capacity and to guide the appropriate use of blood components in cardiac surgery is also effective in reducing the need for transfusion. Patients on antithrombotic drug therapy may need reversal before surgery to avoid excessive blood loss, or intraoperatively in cases of unexpected bleeding. Available options are protamine for unfractionated or low-molecular-weight heparin, recombinant activated factor VII for fondaparinux, prothrombin complex concentrate for vitamin K antagonists and possibly for oral factor Xa inhibitors, dialysis and possibly activated prothrombin complex concentrate for oral thrombin inhibitors, desmopressin for aspirin and possibly for thienopyridines, and platelet transfusions for the latter.

Developing performance measures for patient blood management

In 2005, The Joint Commission set about assessing the need for performance measures associated with the provision of blood products. Through a rigorous process, seven patient blood management performance measures were created. These measures incorporated a measure requiring transfusion consent; three measures requiring the combination of a laboratory value and a rationale for transfusion of plasma, platelets, or red blood cells; a measure requiring standard documentation about a transfusion; a measure evaluating preoperative anemia screening; and a measure of preoperative type screening and antibody testing before the start of major blood loss surgery. This article describes the process of this measure development and summarizes the final measures and some of the evidence supporting the measures.

Platelet transfusions: trigger, dose, benefits, and risks

Over the last half century, platelet transfusion has been an effective therapy for the prevention and treatment of bleeding, particularly in patients with hematologic malignancies. Recent randomized trials have demonstrated that current practices may be suboptimal in a number of ways. The rationale for parsimony in the use of this powerful therapy includes previously described severe and fatal adverse outcomes (including refractoriness, hemolysis from ABO-mismatched transfusions, acute lung injury, and bacterial sepsis), newly described serious potential risks (including thrombosis and earlier leukemic recurrence), difficulty in maintaining adequate supplies of platelets, the need to place volunteer donors on cell separators to provide the product, and cost. Recent findings demonstrate that the platelet count threshold for prophylactic transfusion can be as low as 10,000/µL, and a therapeutic rather than a prophylactic strategy of transfusion for bleeding manifestations only may be equally safe for most patients. Another recently completed study suggests that very low doses of platelet transfusions (the equivalent of half a unit of apheresis platelets or two to three units of whole blood-derived platelets) are as effective at preventing bleeding as much higher doses. One question for which there are no randomized trial data is at what threshold prophylactic platelet transfusion should be given before invasive procedures or major surgery. The typically recommended threshold of 50,000/µL is based only on expert opinion, and substantial observational data indicate that this threshold leads to many transfusions that are likely unnecessary and therefore represent risk with little or no additional benefit.

The platelet as an immune cell-CD40 ligand and transfusion immunomodulation

The discovery that platelets possess cell membrane, cytoplasmic, and secreted forms of the co-stimulatory molecule CD40 ligand (CD40L, also known as CD154) has led to a revolution in the view of this anucleate, differentiated cell fragment, previously thought only to be involved in blood clotting (hemostasis). During the last decade, it has become clear that platelets function in innate and adaptive immunity and possess pro-inflammatory, as well as pro-thrombotic properties. They interact not only with other platelets and endothelial cells, but also with lymphocytes, dendritic cells, and structural cells such as fibroblasts. Soluble forms of CD40L (sCD40L) in the human circulation are almost entirely derived from platelets. Elevated levels of CD40L are associated with clinically important conditions, such as vascular disease, abnormal clotting (thrombosis), lung injury, and autoimmune disease. Each year millions of platelet transfusions are given to patients that contain large amounts of sCD40L. sCD40L in the supernatant of stored platelets can induce cytokines, chemokines, and lipid mediators by activating CD40 bearing cells. Increased levels of sCD40L in transfused blood are associated with transfusion-related acute lung injury, a potentially fatal complication, as well as more common, milder transfusion reactions such as fever and rigors. These effects come under the rubric of transfusion immunomodulation, which postulates that transfusion recipient biology, particularly immune function, is dramatically altered by transfusion of stored allogeneic blood.

The silent risks of blood transfusion

PURPOSE OF REVIEW

Clinical research has identified blood transfusion as an independent risk factor for immediate and long-term adverse outcomes, including an increased risk of death, myocardial infarction, stroke, renal failure, infection and malignancy. New findings have called into question the traditional assumptions clinicians utilize in evaluating the risks and benefits of blood transfusion. Appreciation of newly recognized risks is important for conserving scarce resources and optimizing patient outcomes.

RECENT FINDINGS

Recent clinical outcomes research has examined the impact of blood transfusion on critically ill patients, trauma patients, patients undergoing cardiac surgery, patients experiencing acute coronary syndromes, oncology patients and others. These studies provide additional evidence of adverse outcomes associated with blood transfusion in a wide variety of clinical contexts.

SUMMARY

The benefits of blood transfusion have never been conclusively demonstrated, but evidence of transfusion-related harm continues to accumulate. Given the transfusion triggers that currently predominate in clinical practice it appears that clinical outcomes could improve significantly with more widespread adoption of restrictive transfusion strategies.