Blood transfusion and the risk of atrial fibrillation after cardiac surgery

The association of hemoglobin with postoperative delirium and atrial fibrillation after cardiac surgery: a retrospective sub-study

BACKGROUND

Most cardiac surgery patients experience postoperative anemia. Delirium and Atrial Fibrillation (AF) are common and independent predictors of morbidity and mortality. Few reports examine their association with postoperative anemia. This study aims to quantify the association between anemia and these outcomes in patients undergoing cardiac surgery.

METHODS

This post-hoc analysis of the DECADE randomized controlled trial ran at six academic US hospitals. Patients aged 18-85 years with heart rate > 50 bpm undergoing cardiac surgery who had daily hemoglobin measurements in the first 5 Postoperative Days (POD) were included. Delirium was assessed twice daily with the Confusion Assessment Method for the ICU (CAM - ICU), preceded by the Richmond Agitation and Sedation Scale, with patients excluded from assessment if sedated. Patients had daily hemoglobin measurements, continuous cardiac monitoring plus twice-daily 12-lead electrocardiograms, up to POD4. AF was diagnosed by clinicians blinded to hemoglobin levels.

RESULTS

Five hundred and eighty-five patients were included. Mean postoperative hemoglobin Hazard Ratio (HR): 0.99 (95% CI 0.83, 1.19; p = 0.94) per 1 g.dL-1 hemoglobin decrease. 197 (34%) developed AF, mainly on POD = 2.3. Estimated HR = 1.04 (95% CI 0.93, 1.17; p = 0.51) per 1 g.dL-1 hemoglobin decrease.

CONCLUSIONS

Most patients undergoing major cardiac surgery were anemic in the postoperative phase. AF and delirium occurred in 34% and 12% of patients, respectively, but neither were significantly correlated with postoperative hemoglobin.

Impact of perfusion method on perioperative red blood cell transfusions and new-onset postoperative atrial fibrillation in mitral valve surgery patients

INTRODUCTION

Red blood cell (RBC) transfusions are common in cardiac surgery and reportedly associated with increased mortality and morbidity, including increased risk of postoperative new-onset atrial fibrillation (NOAF). The aim of this study was to compare minimal invasive extracorporeal circulation (MiECC) and conventional extracorporeal circulation (CECC) in terms of RBC transfusions and the incidence of NOAF in mitral valve surgery.

METHODS

The study population consisted of 89 MiECC and 169 CECC patients undergoing mitral valve surgery as an isolated procedure (80.6% of the patients) or in combination with coronary artery bypass grafting (19.4% of patients). 79.4% of the patients were male and the mean age was 62.1 years.

RESULTS

30.0% of patients aged < 65 years and 48.1% of patients aged ≥ 65 years needed RBC transfusion. The overall need for RBC transfusions did not differ between the treatment groups. Among patients < 65 years of age transfusions of ≥ 3 units were less frequent in MiECC than in CECC patients (OR 0.31, 95% CI 0.10-0.98, p = 0.045). The overall incidence of NOAF was 41.8% with no significant difference between MiECC and CECC groups. Red blood cell transfusions were associated with an increased risk of NOAF in an unadjusted analysis but not after adjustment for age and sex (OR 1.25, 95% CI 0.64-2.43, p = 0.515).

CONCLUSIONS

In mitral valve surgery MiECC compared to CECC was associated with less need of RBC units and platelets, particularly in patients aged < 65 years. Use of RBC transfusions was associated with increased risk of NOAF significantly only in unadjusted analysis.

Myocardial Blush Grade Predicts Postoperative Atrial Fibrillation following Mitral Valve Replacement: A Novel Perspective

Background: Atrial fibrillation (AF) remains the most common arrhythmia following mitral valve surgery. Although numerous clinical and laboratory indicators and possible mechanisms of postoperative AF (PoAF) have been described, the role of microvascular dysfunction in pathogenesis has not been assessed. We aimed to evaluate the association between microvascular dysfunction and PoAF in patients undergoing isolated mitral valve replacement. Methods: 188 patients undergoing mitral valve replacement were included in this retrospective study. Demographic characteristics of the patients were recorded. Angiographic assessment of microvascular perfusion was performed using the myocardial blush grading technique for each patient. Univariate and multivariate logistic regression analyses were utilized to determine predictors of PoAF. Results: Of 188 patients (56.69 ± 8.9 years, 39.4% male) who underwent mitral valve replacement, 64 (34%) patients developed PoAF. In the PoAF group, a lower basal hemoglobin level (12.64 ± 0.89 vs. 14.46 ± 0.91 g/dL; p < 0.001), a higher left atrial diameter [5.9 (5.2-6.47) vs. 4.9 (4.5-5.8) cm; p < 0.001], and a lower total blush score (TBS) (8.33 ± 0.84 vs. 8.9 ± 0.31; p < 0.001) were detected. Multivariate logistic regression analysis revealed that preoperative LA diameter (OR:2.057; 95% CI: 1.166-3.63; p = 0.013), preoperative hemoglobin (OR:0.12; 95% CI: 0.058-0.245; p < 0.001), and abnormal TBS (OR:15.1; 95% CI: 1.602-142.339; p = 0.018) were independent predictors of PoAF. Conclusions: Our findings demonstrated that TBS at the preoperative period was an independent predictor of PoAF in patients undergoing isolated mitral valve replacement.

The pressure field as a methodology for fluid management and red cell preservation during cardiac surgery

PURPOSE

Anemia and red cell transfusion contribute to morbidity and mortality of surgery. The concept of patient blood management to mitigate preoperative anemia, optimize coagulation, conserve red cells intraoperatively and accept lower post-operative transfusion thresholds has recently gained widespread acceptance across a range of surgical disciplines. Fluid administration is likely to contribute significantly to perioperative anemia and red-cell transfusion requirements, yet a robust basis for managing fluid administration in this context has not been articulated. There is an urgent need for this.

METHODS

We developed 'the pressure field method' as a novel approach to guiding the administration of fluid and drugs to optimize tissue perfusion. The pressure field method was used for the intraoperative management of 67 patients undergoing semi-elective cardiac surgery. We compared intraoperative anemia and transfusion requirements in this cohort with a conventional group of 413 patients undergoing cardiac surgery.

RESULTS

In the pressure field group, no patients required transfusion whereas in the conventional group, 16% required transfusion during bypass and these patients received an average of 2.4 units of packed red cells (P < 0.0001). The average decrease in hemoglobin in the pressure field group was only 13 g/L, whereas in the conventional group it was 52 g/L (P < 0.0001). 80% of the pressure field group received no intravenous fluid during cardiac surgery, and the average intraoperative fluid load was 115 mL.

CONCLUSION

The pressure field method appears to reduce transfusion requirements due to decreased intraoperative fluid loading.

Robotic-assisted versus conventional off-pump coronary surgery in women: A propensity-matched study

BACKGROUND

Off-pump coronary artery bypass (OPCAB) previously demonstrated its potential benefits in women; however, robotic-assisted OPCAB was scarcely studied.

OBJECTIVES

To investigate whether robotic-assisted OPCAB could further improve the outcomes in women and the potential impact of hybrid approaches with stents and completeness of revascularization on the late outcomes.

METHODS

Women who underwent robotic-assisted or conventional OPCAB (with sternotomy) between May 2005 and January 2021 at Lankenau Heart Institute were included. Propensity score matching was used to match 273 pairs on 27 characteristics.

RESULTS

In the intraoperative period, women who underwent robotic-assisted OPCAB presented longer operative times (6.00 vs. 5.38 h; p < 0.001), higher rates of extubation in the operating room (83.9% vs. 75.5%; p = 0.019) and lower rates of blood transfusion (13.2% vs. 32.2%; p < 0.001). In the postoperative period, women who underwent robotic-assisted OPCAB presented lower rates of new onset atrial fibrillation (16.8% vs. 25.6%; p = 0.016), need of blood transfusion (33.0% vs. 54.9%; p < 0.001), shorter intensive care unit (ICU) (46.1 vs. 49.8 h; p = 0.006) and hospital length of stay (5.0 vs. 6.0 days; p < 0.001). We observed no statistically significant differences in the rates of operative death between the groups (1.47% vs. 1.47%; p = 0.771). In the follow-up, we observed no differences in terms of overall survival regardless of hybrid procedures with stents and completeness of revascularization.

CONCLUSIONS

Robotic-assisted OPCAB in women is as safe as conventional OPCAB and may further improve outcomes. Hybrid coronary revascularization was a valuable adjunct in the robotic scenario and completeness of revascularization did not play a role in this setting.

Association between Anemia and New-Onset Atrial Fibrillation in Critically Ill Patients in the Intensive Care Unit: A Retrospective Cohort Analysis

New-onset atrial fibrillation (NOAF) is one of the leading causes of morbidity and mortality, especially in older patients in the intensive care unit (ICU). Although many comorbidities are associated with NOAF, the effect of anemia on the onset of atrial fibrillation is still unknown. This study aimed to test the hypothesis that anemia is associated with an increased risk of developing NOAF in critically ill patients in intensive care. We performed a retrospective analysis of critically ill patients who underwent routine hemoglobin and electrocardiography monitoring in the ICU. Receiver operating characteristics analysis determined the hemoglobin (Hb) value that triggered NOAF formation. Bivariate correlation was used to determine the relationship between anemia and NOAF. The incidence of NOAF was 9.9% in the total population, and 12.8% in the patient group with anemia. Analysis of 1931 patients revealed a negative association between anemia and the development of NOAF in the ICU. The stimulatory Hb cut-off value for the formation of NOAF was determined as 9.64 g/dL. Anemia is associated with the development of NOAF in critically ill patients in intensive care.

Postoperative Atrial Fibrillation Reduced by Intraoperative and Postoperative Cell Saver System in Coronary Artery Bypass Graft Surgery

OBJECTIVE

Postoperative atrial fibrillation is commonly seen after cardiac surgery. One of the contributing factors is mediastinal shed blood and inflammation. Cell salvage techniques can reduce allogenic blood transfusion and reduce inflammation. The aim of this study was to investigate the reduction of postoperative atrial fibrillation by using the cell-salvage system.

METHODS

Patients who underwent isolated coronary artery bypass graft surgery (n = 498) were analyzed retrospectively in 2 groups. Postoperative atrial fibrillation group (n = 75) and non-postoperative atrial fibrillation group (n = 423). Preoperative and postoperative demographic and clini- cal data were compared between the 2 groups, respectively. Postoperative atrial fibrillation and possible contributing factors were analyzed with multinomial logistic regression analysis.

RESULTS

In the postoperative atrial fibrillation group, the patients' age and European System for Cardiac Operative Risk Evaluation (Euroscore) were higher than in the non-postoperative atrial fibrillation group (P = .001 and P = .003, respectively). Postoperative intensive care unit stay and hospital stay were longer in the postoperative atrial fibrillation group than in the non-postoperative atrial fibrillation group (P = .001 and P = .046, respectively). There were no statistical differences in mortality between groups. The incidence of postoperative atrial fibrillation decreased with the use of cell saver system and low Euroscore.

CONCLUSION

The use of a cell salvage device intraoperatively and during the early postoperative period can decrease the incidence of postop- erative atrial fibrillation group.

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.

Biochemical predictors of postoperative atrial fibrillation following cardiac surgery

Background

New-onset postoperative atrial fibrillation (POAF) is common after cardiac surgery. Early identification of its risk factors during the preoperative period would help in reducing the associated morbidity, mortality, and healthcare costs.

Aim of the study

This study aimed to identify the predictors of POAF following open cardiac surgery, with emphasis on biochemical parameters.

Methods

A total of 1191 patients with no preoperative atrial fibrillation (AF) and undergoing open cardiac surgery for any reason were included in this retrospective study. Data on clinical and biochemical parameters, the occurrence of new-onset AF, and its clinical course were retrieved from the hospital database.

Results

During the early postoperative period 330 patients (27.7%) developed atrial fibrillation, at median third postoperative day (range 1–6 days) and 217 (65.8%) responded to treatment. Multivariate analysis identified the following as the significant independent predictors of any POAF: EF < 60% (Odds ratio (OR), 2.6), valvular intervention (OR, 2.4), liver failure (OR, 2.4), diabetes (OR, 1.6), low hematocrit (OR, 2.1), low thrombocyte (OR, 5.6), low LDL (OR, 1.6), high direct bilirubin (OR, 2.0), low GFR (OR, 1.6), and high CRP (OR, 2.0). Following parameters emerged as significant independent predictors of persistent AF: EF < 60% (OR, 1.9), diabetes (OR, 2.1), COPD (OR, 1.8), previous cardiac surgery (OR, 3.1), valvular intervention (OR, 2.4), low hematocrit (OR, 1.9), low LDL (OR, 2.1), high HbA1c (OR, 2.0), and high CRP (OR, 2.7).

Conclusions

Certain parameters assessed during preoperative physical and laboratory examinations have the potential to be used as markers of POAF.

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.

Management of Common Postoperative Complications

Postoperative complications are common. Major guidelines have been published on stratifying and managing adverse cardiovascular events and thromboembolic events, but there is often less literature supporting management of other, more common, postoperative complications, including acute kidney injury, gastrointestinal complications, postoperative anemia, fever, and delirium. These common conditions are frequently seen in hospital and can contribute to longer lengths of stay and rising health care costs. These complications are often due to the interplay between both patient-specific and surgery-specific risk factors. Identifying these risk factors, while addressing and optimizing modifiable risks, can mitigate the likelihood of developing these postoperative complications. Often, a multidisciplinary approach, including care team members through all phases of the surgical encounter, is needed. Cardiovascular and thrombotic complications have been addressed in prior articles in this perioperative series. We aim to cover other common postoperative complications, such as acute renal failure, postoperative gastrointestinal complications, anemia, fever, and delirium that often contribute to longer lengths of stay, rising health care costs, and increased morbidity and mortality for patients.

Fragmented QRS complexes are associated with postoperative atrial fibrillation development after coronary artery bypass grafting surgery

OBJECTIVE

Postoperative atrial fibrillation (PoAF) is one of the most frequent complications and a major risk factor of morbidity and mortality after coronary artery bypass grafting (CABG). Fragmented QRS complex (fQRS) on a 12-lead surface ECG is recently gained increasing attention as a simplified noninvasive ECG marker with diagnostic and prognostic value in various cardiac conditions. The aim of the present study was to evaluate the association between development of PoAF and presence of fQRS on admission ECG in patients undergoing CABG surgery.

METHODS

A total of 242 patients who underwent CABG between February 2016 and June 2018 were included in this study. The patients were divided into two groups as developing and nondeveloping PoAF groups in the postoperative period. fQRS was defined as the presence of various RSR' patterns including an additional R wave, notching of the R or S waves, or the presence of more than one fragmentation in two contiguous leads.

RESULTS

In-hospital mortality was higher in PoAF (+) group compared to PoAF (-) group (20.5 vs. 6.4%, P = 0.004). PoAF rate was higher in fQRS (+) group than fQRS (-) group (25.3 vs. 9.8%, P = 0.001). In multivariate analysis, the presence of fQRS complexes on admission ECG [odds ratio (OR) 2.801, 95% confidence interval (CI) 1.262-6.211, P = 0.011) and hemoglobin (OR 0.794; 95% CI, 0.641-0.985; P = 0.036) were identified as independent predictors of PoAF after CABG surgery.

CONCLUSION

The presence of fQRS on admission ECG was found to be an independent predictor of PoAF in patients undergoing isolated CABG.

Elucidation of the novel role of ethnicity and diabetes in poorer outcomes after cardiac surgery in a multiethnic Southeast Asian cohort

BACKGROUND

Although diabetes is associated with ethnicity and worse cardiac surgery outcomes, no research has been done to study the effect of both diabetes and ethnicity on cardiac surgery outcomes in a multiethnic Southeast Asian cohort. Hence, this study aimed to delineate the association of ethnicity on outcomes after cardiac surgery among diabetics in a multiethnic Southeast Asian population.

METHODS

Perioperative data from 3008 adult patients undergoing elective cardiac surgery from 2008 to 2011 at the two main heart centers in Singapore was analyzed prospectively, and confirmatory analysis was conducted with the generalized structural equation model.

RESULTS

Diabetes was significantly associated with postoperative acute kidney injury (AKI) and postoperative hyperglycemia. Postoperative AKI, Malay ethnicity, and blood transfusion were associated with postoperative dialysis. Postoperative AKI and blood transfusion were also associated with postoperative arrhythmias. In turn, postoperative dialysis and arrhythmias increased the odds of 30-day mortality by 7.7- and 18-fold, respectively.

CONCLUSIONS

This study identified that diabetes is directly associated with postoperative hyperglycemia and AKI, and indirectly associated with arrhythmias and 30-day mortality. Further, we showed that ethnicity not only affects the prevalence of diabetes, but also postoperative diabetes-related outcomes.

Red blood cell distribution width: A marker of anisocytosis potentially associated with atrial fibrillation

The incorporation of biomarkers in the actually used risk scores seem to be helpful for early identifying atrial fibrillation (AF) patients at higher risk. The aim of this critical review of the scientific literature is to investigate the potential clinical significance of red blood cell distribution width (RDW) in AF. A systematic electronic search was carried out to identify all articles describing an epidemiological association between RDW and AF in adult human populations. Data abstraction was conducted on a final number of 35 articles (13 cross-sectional, 12 prospective and 10 retrospective studies). The results of these epidemiological investigations were all virtually concordant to emphasize that an enhanced RDW value is not only a predictive factor and a marker of AF but its measurement may also be helpful for predicting the risk of developing many adverse complications in patients with AF, such as recurrence and duration of AF, hospitalization for heart failure, bleeding, left atrial thrombosis and stasis, thromboembolic events and mortality. AF patients with RDW values exceeding the local reference range may be more aggressively investigated and managed, in order to identify and attenuate the impact of possible underlying disorders causing both anisocytosis and AF.

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.

Blood transfusion and risk of atrial fibrillation after coronary artery bypass graft surgery: A meta-analysis of cohort studies

The aim of this study was to systematically evaluate the effect of blood transfusion (BT) on postoperative atrial fibrillation (AF) in adult patients who had undergone coronary artery bypass grafting (CABG) surgery.PubMed, Embase, and Cochrane Library databases from inception to January 2017 were searched. Cohort studies were searched that evaluated the association between BT and the risk of postoperative AF in adult patients who had undergone CABG surgery. Study quality was assessed by using the Newcastle-Ottawa scale (NOS). A meta-analysis was performed with the random-effect model.Eight cohort studies involving 7401 AF cases and 31,069 participants were identified and included in our data analysis. The pooled odds ratio of postoperative AF in patients with BT was 1.45 (95% confidence interval, 1.26-1.67), with significant heterogeneity (P < .0001, I = 79%). Excluding one study that had an off-pump CABG did not significantly impact this result (odds ratio, 1.36; 95% confidence interval, 1.23-1.50; n = 7). To examine the stability of the primary results, we performed subgroup analyses. The association between BT and the risk of postoperative AF was similar, as determined in the stratified analyses conducted according to study design, type of surgery, and country.The findings of the present meta-analysis demonstrated a statistically significant increase in postoperative AF risk among adult patients with BT. Further prospective large-scale studies are needed to establish causality and to elucidate the underlying mechanisms.

Total arterial revascularization in patients with acute myocardial infarction - feasibility and outcomes

BACKGROUND

In acute situations such as acute myocardial infarction (AMI) with indication for coronary artery bypass grafting (CABG), total arterial revascularization (TAR) is often rejected in favour of saphenous vein (SV) grafting, which is assumed to allow for quicker vessel harvesting, a simpler anastomosis technique, and thus quicker revascularization and fewer bleeding complications. The aim of this study was to evaluate whether reluctance to apply TAR in AMI is still justified from a technical point of view in the current era and whether superiority of TAR results is also evident in emergency patients with AMI undergoing CABG.

METHODS

In this retrospective analysis of 434 consecutive patients undergoing CABG for AMI with either TAR or with a combination of one internal mammary artery and SV grafts between 2008 and 2014, procedural data, short-term and mid-term outcome were compared. Propensity score matching of the groups was performed.

RESULTS

After propensity score matching, 250 patients were included in the analysis (TAR group: n = 98; SV group n = 152). The procedural time (TAR group: 211 min vs. SV group: 200 min, p = 0.46) did not differ between the groups. Erythrocyte transfusion rates were higher in the SV group (76% vs. 57%; p < 0.001). Rates of re-exploration for bleeding did not differ. Thirty-day mortality rates were comparable (TAR group: 3.4% vs. SV group: 4.5%, p = 0.68). Kaplan-Meier analysis until 7 years postoperatively revealed a tendency for improved survival after TAR (75% vs. 62%; log-rank p = 0.12).

CONCLUSION

TAR neither impairs rapid revascularization nor reduces its safety in patients with AMI. It may result in improved long-term outcome and should be preferred in the clinical setting of AMI.

Implementing a protocol to optimize blood use in a cardiac surgery service: results of a pre-post analysis and the impact of high-volume blood users

BACKGROUND

Blood transfusions are a common and costly intervention for cardiac surgery patients. Evidence suggests that a more restrictive transfusion strategy may reduce costs and transfusion-related complications without increasing perioperative morbidity and mortality.

STUDY DESIGN AND METHODS

A transfusion-limiting protocol was developed and implemented in a cardiovascular surgery unit. Over a 5-year period, data were collected on patient characteristics, procedures, utilization of blood products, morbidity, and mortality, and these were compared before and after the protocol was implemented.

RESULTS

After the protocol was put in place, fewer patients required transfusions (38.2% vs. 45.5%, p = 0.004), with the greatest reduction observed in postoperative blood use (29.1% vs. 37.2%, p = 0.001). In-hospital morbidity and mortality did not increase. When patients who received transfusions were stratified by procedure, the protocol was most effective in reducing transfusions for patients undergoing isolated coronary artery bypass grafting (CABG; 4.09 units vs. 2.51 units, p = 0.009) and CABG plus valve surgery (10.32 units vs. 4.77 units, p = 0.014). A small group of patients were disproportionate recipients of transfusions, with approximately 6% of all patients receiving approximately half of the blood products.

CONCLUSION

A protocol to limit transfusions decreased the proportion of cardiothoracic surgery patients who received blood products. A very small group of patients received a large number of transfusions, and within that group the observed mortality was significantly higher than in the general patient population. Current protocols cannot possibly account for these patients, and this should be considered when analyzing the performance of protocols designed to reduce unnecessary transfusions.

Storage time of intraoperative transfused allogeneic red blood cells is not associated with new-onset postoperative atrial fibrillation in cardiac surgery

BACKGROUND

Allogeneic red blood cell (RBC) transfusion has been associated with new-onset postoperative atrial fibrillation (POAF) following cardiac surgery. Prolonged storage time of RBC may increase the risk. The primary aim of the study was to evaluate whether the storage time of RBC is associated with development of POAF.

MATERIALS AND METHODS

Pre-, per- and postoperative data were retrieved from the Western Denmark Heart Registry and local blood banks regarding patients who underwent coronary artery bypass surgery, valve surgery or combined procedures in Aalborg or Aarhus University Hospital during 2010-2014. Multiple logistic regression was used to determine the risk of POAF according to transfusion of RBC on the day of surgery. Furthermore, we determined trend in storage time of RBC according to risk of POAF using restricted cubic splines. Patients with a history of preoperative atrial fibrillation, patients who received transfusions preoperative and patients who died at the day of surgery were among excluded patients.

RESULTS

A total of 2,978 patients with a mean age of 66.4 years were included and 609 patients (21%) received RBC transfusion on the day of surgery. POAF developed in 752 patients (25%) and transfused patients were at an increased risk compared with non-transfused patients (adjusted Odds Ratios for patients receiving RBC: 1.37; 95% CI: 1.11-1.69, P-value = 0.004). However, RBC transfusion was not necessarily the cause of POAF and may only be a marker for development of POAF. There was no significant association between storage time of RBC and POAF.

CONCLUSIONS

In contrast to intraoperative allogeneic RBC transfusion in general, increased storage time of RBC is not associated with development of POAF in cardiac surgery.

A comparison of red blood cell transfusion utilization between anti-activated factor X and activated partial thromboplastin monitoring in patients receiving unfractionated heparin

Essentials Anti-activated factor X (Anti-Xa) monitoring is more precise than activated partial thromboplastin (aPTT). 20 804 hospitalized cardiovascular patients monitored with Anti-Xa or aPTT were analyzed. Adjusted transfusion rates were significantly lower for patients monitored with Anti-Xa. Adoption of Anti-Xa protocols could reduce transfusions among cardiovascular patients in the US.

SUMMARY

Background Anticoagulant activated factor X protein (Anti-Xa) has been shown to be a more precise monitoring tool than activated partial thromboplastin time (aPTT) for patients receiving unfractionated heparin (UFH) anticoagulation therapy. Objectives To compare red blood cell (RBC) transfusions between patients receiving UFH who are monitored with Anti-Xa and those monitored with aPTT. Patients/Methods A retrospective cohort study was conducted on patients diagnosed with acute coronary syndrome (ACS) (N = 14 822), diagnosed with ischemic stroke (STK) (N = 1568) or with a principal diagnosis of venous thromboembolism (VTE) (N = 4414) in the MedAssets data from January 2009 to December 2013. Anti-Xa and aPTT groups were identified from hospital billing details, with both brand and generic name as search criteria. Propensity score techniques were used to match Anti-Xa cases to aPTT controls. RBC transfusions were identified from hospital billing data. Multivariable logistic regression was used to identify significant drivers of transfusions. Results Anti-Xa patients had fewer RBC transfusions than aPTT patients in the ACS population (difference 17.5%; 95% confidence interval [CI] 16.4-18.7%), the STK population (difference 8.2%; 95% CI 4.4-11.9%), and the VTE population (difference 4.7%; 95% CI 3.3-6.1%). After controlling for patient age and gender, diagnostic risks (e.g. anemia, renal insufficiency, and trauma), and invasive procedures (e.g. cardiac catheterization, hemodialysis, and coronary artery bypass graft), Anti-Xa patients were less likely to have a transfusion while hospitalized for ACS (odds ratio [OR] 0.16, 95% CI 0.14-0.18), STK (OR 0.41, 95% CI 0.29-0.57), and VTE (OR 0.35, 95% CI 0.26-0.48). Conclusion Anti-Xa monitoring was associated with a significant reduction in RBC transfusions as compared with aPTT monitoring alone.