Association of red blood cell transfusion and short- and longer-term mortality after coronary artery bypass graft surgery

Perioperative Mass Transfusion Affects In-Hospital but Not Follow-Up Survival in Patients with Acute Type A Aortic Dissection

Background and Objectives: The aim of this study was to analyze the influence of mass transfusion on the postoperative outcome and survival in patients presenting with acute Type A aortic dissection. Materials and Methods: Between 2002 and 2020, a total of 505 patients were surgically treated for an acute Type A aortic dissection. Mass transfusion was defined as the peri- and postoperative replacement by transfusion of 10 units. Patient characteristics and outcomes were analyzed and compared between patients with and without mass transfusion. Results: Mass transfusion occurred in 105 patients (20%). The incidences of symptomatic coronary malperfusion (p = 0.017) and tamponade (p = 0.043) were higher in patients with mass transfusion. There was no statistically significant difference in the distal extension of the aortic dissection between the two groups. A valved conduit was significantly more common in patients with mass transfusion (p = 0.007), while the distal aortic repair was similar between the two groups. Cardiopulmonary bypass time (p < 0.001), cross clamp time (p < 0.001) and in-hospital mortality were significantly higher in patients with mass transfusion (p < 0.001), but the survival after discharge (landmark-analysis) showed equal survival between patients with and without mass transfusion (log rank: p = 0.4). Mass transfusion was predictive of in-hospital mortality (OR: 3.308, p < 0.001) but not for survival after discharge (OR: 1.205, p = 0.661). Conclusions: Mass transfusion is necessary in many patients with acute Type A aortic dissection. These patients present sicker and require longer surgery. However, mass transfusion does not influence survival after discharge.

Platelet Toll-like Receptor 4–Related Innate Immunity Potentially Participates in Transfusion Reactions Independent of ABO Compatibility: An Ex Vivo Study

The role of platelet TLR4 in transfusion reactions remains unclear. This study analyzed platelet TLR4 and certain damage-associated molecular patterns (DAMPs) and evaluated how ABO compatibility affected TLR4 expression after a simulated ex vivo transfusion. A blood bank was the source of donor red blood cells. Blood from patients undergoing cardiac surgery was processed to generate a washed platelet suspension to which the donor blood was added in concentrations 1, 5, and 10% (v/v). Blood-mixing experiments were performed on four groups: a 0.9% saline control group (n = 31); a matched-blood-type mixing group (group M, n = 20); an uncross-matched ABO-specific mixing group (group S, n = 20); and an ABO-incompatible blood mixing group (group I, n = 20). TLR4 expression in the platelets was determined after blood mixing. We evaluated levels of TLR4-binding DAMPs (HMGB1, S100A8, S100A9, and SAA), lipopolysaccharide-binding protein, and endpoint proteins in the TLR4 signaling pathway. In the M, S, and I groups, 1, 5, and 10% blood mixtures significantly increased TLR4 expression (all p < 0.001) in a concentration-dependent manner. Groups M, S, and I were not discovered to have significantly differing TLR4 expression (p = 0.148). HMGB1, S100A8, and S100A9 levels were elevated in response to blood mixing, but SAA, lipopolysaccharide-binding protein, TNF-α, IL-1β, and IL-6 levels were not. Blood mixing may elicit innate immune responses by upregulating platelet TLR4 and DAMPs unassociated with ABO compatibility, suggesting that innate immunity through TLR4-mediated signaling may induce transfusion reactions.

Iron supplementation for patients undergoing cardiac surgery: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Iron supplementation has been evaluated in several randomized controlled trials (RCTs) for its potential to increase baseline hemoglobin and decrease red blood cell transfusion during cardiac surgery. This study's main objective was to evaluate the current evidence for iron administration in cardiac surgery patients.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, Web of Science databases, and Google Scholar from inception to 19 November 2020 for RCTs evaluating perioperative iron administration in adult patients undergoing cardiac surgery. The RCTs were assessed using a risk of bias assessment and the quality of evidence was assessed using the grading of recommendations, assessments, development, and evaluations.

RESULTS

We reviewed 1,767 citations, and five studies (n = 554) met the inclusion criteria. The use of iron showed no statistical difference in incidence of transfusion (risk ratio, 0.86; 95% confidence interval, 0.65 to 1.13). Trial sequential analysis suggested an optimal information size of 1,132 participants, which the accrued information size did not reach.

CONCLUSION

The current literature does not support or refute the routine use of iron therapy in cardiac surgery patients.

TRIAL REGISTRATION

PROSPERO (CRD42020161927); registered 19 December 2019.

Relative impact of red blood cell transfusion and anaemia on 5-year mortality in cardiac surgery

OBJECTIVES

The aim was to compare the relative effects of red blood cell (RBC) transfusion and preoperative anaemia on 5-year mortality following open-heart cardiac surgery using structural equation modelling. We hypothesized that patient risk factors associated with RBC transfusion are of larger importance than transfusion itself.

METHODS

This prospective cohort study, part of the Cardiac Surgery Outcome Study at St. Olavs University Hospital, Trondheim, Norway, included open-heart on-pump cardiac surgery patients operated on from 2000 through 2017 (n = 9315). Structural equation modelling, which allows for intervariable correlations, was used to analyse pathway diagrams between known risk factors and observed mortality between 30 days and 5 years postoperatively. Observation times between 30 days and 1 year, and 1-5 years postoperatively were also compared with the main analysis.

RESULTS

In a simplified model, preoperative anaemia had a larger effect on 5-year mortality than RBC transfusion (standardized coefficients: 0.17 vs 0.09). The complete model including multiple risk factors showed that patient risk factors such as age (0.15), anaemia (0.10), pulmonary disease (0.11) and higher creatinine level (0.12) had larger effects than transfusion (0.03). Results from several sensitivity analyses supported the main findings. The models showed good fit.

CONCLUSIONS

Preoperative anaemia had a larger impact on 5-year mortality than RBC transfusion. Differences in 5-year mortality were mainly associated with patient risk factors.

Iron supplementation for patients undergoing cardiac surgery: a protocol for a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Iron administration has been evaluated in several randomized controlled trials for the potential of increasing baseline hemoglobin values and decreasing the incidence of red blood cell transfusion during cardiac surgery. We describe the protocol for a study aiming to evaluate the efficacy and safety of perioperative iron administration in patients undergoing cardiac surgery.

METHODS

We will search MEDLINE, Embase, the Cochrane Central Register of Controlled Trials and the Web of Science, from inception to Nov. 19, 2020, for randomized controlled trials in any language evaluating the perioperative administration of iron in adult patients undergoing cardiac surgery; we will also include the first 50 results from Google Scholar. The primary outcome will be the incidence of red blood cell transfusion from the study intervention time until 8 weeks postoperatively. The secondary outcomes will be the number of red blood cell units transfused; change in ferritin level, reticulocyte count and hemoglobin concentration after iron administration; and adverse events. We will assess the risk of bias with the Cochrane Collaboration Risk of Bias Tool, and will analyze the primary and secondary outcomes using a random-effects model.

INTERPRETATION

This study will summarize the current evidence about perioperative iron administration in patients undergoing cardiac surgery, help determine whether this intervention should be included in enhanced-recovery protocols, and shape future research if needed. The final manuscript will be submitted to a peer-reviewed journal.

TRIAL REGISTRATION

PROSPERO no. CRD42020161927.

The risk factors for delayed recovery in patients with cardiopulmonary bypass: Why should we care?

Cardiopulmonary bypass (CPB) is very commonly performed among the cardiovascular surgeries, and delayed recovery (DR) is a kind of serious complications in patients with CPB. It is necessary to assess the risk factors for DR in patients with CPB, to provide evidence into the management of CPB patients.Patients undergoing CPB in our hospital from January 2018 to March 2020 were included. Cases that consciousness has not recovered 12 hours after anesthesia were considered as DR. The preoperative and intraoperative variables of CPB patients were collected and analyzed. Logistic regressions were conducted to analyze the potential influencing factor.A total of 756 CPB patients were included, and the incidence of DR was 9.79%. There were significant differences on the age, aspartate aminotransferase (AST), glutamic pvruvic transaminase (ALT), blood urea nitrogen (BUN), and serum creatinine (SCr) between patients with and without DR (all P < .05); there were no significant differences in the types of surgical procedure (all P > .05); there were significant differences on the duration of CPB, duration of aortic cross clamp (ACC), duration of surgery, minimum nasopharyngeal temperature, and transfusion of packed red blood cells between patients with and without DR (all P < .05). Logistic regression analysis indicated that duration of CPB ≥132 minutes (odds ratio [OR] 4.12, 1.02-8.33), BUN ≥9 mmol/L (OR 4.05, 1.37-8.41), infusion of red blood cell suspension (OR 3.93, 1.25-7.63), duration of surgery ≥350 minutes (OR 3.17, 1.24-5.20), age ≥6 (OR 3.01, 1.38-6.84) were the independent risk factors for DR in patients with CPB (all P < .05).Extra attention and care are needed for those CPB patients with duration of CPB ≥132 minutes, BUN ≥9 mmol/L, infusion of red blood cell suspension, duration of surgery ≥350 minutes, and age ≥60.