Incidence and prognostic impact of bleeding and transfusion after coronary surgery in low‐risk patients

Perioperative Bleeding Is Not an Independent Risk Factor for Acute Kidney Injury in On-pump Cardiac Surgery-A Post-hoc Analysis of a Randomized Clinical Trial

OBJECTIVES

To study the association between bleeding and acute kidney injury (AKI).

DESIGN

Post-hoc study of a randomized trial of 4% albumin versus Ringer's acetate for cardiopulmonary bypass priming and perioperative volume replacement.

SETTING

Single-center study.

PATIENTS

1,386 on-pump cardiac surgical patients.

MEASUREMENTS AND RESULTS

AKI was defined by the Kidney Disease: Improving Global Outcomes creatinine criteria, and bleeding by the Universal Definition of Perioperative Bleeding (UDPB) classification. With univariably independent factors, two logistic regression analyses (Model 1: AKI Risk Score, EuroSCORE II, and UDPB class; Model 2: risk scores, components of the UDPB classification, and factor VIII/von Willebrand factor concentrate) and a mediation analysis (Model 3: risk scores, UDPB class, and perioperative factors) were performed. A total of 139 (10%) patients developed AKI. In Model 1, UDPB class "severe" (odds ratio: 2.16, 95% confidence interval: 1.19-3.89), "massive" bleeding (6.78, 1.8-25.33), and AKI Risk Score (1.51, 1.29-1.78) were associated with AKI. In Model 2, AKI Risk Score (1.55, 1.33-1.82) and fresh frozen plasma transfusion (1.29, 1.06-1.58) were associated with AKI. In Model 3, the combined UDPB classes "severe" and "massive" bleeding did not have a direct effect (regression coefficient: 0.32, 95% confidence interval: -0.26 to 0.91), while mean arterial pressure (0.08, 0.003-0.21) and fluid balance (0.12, 0.17-0.27) had indirect effects on AKI.

CONCLUSIONS

In on-pump cardiac surgery, perioperative bleeding was not an independent risk factor for AKI but manifested as AKI via hypotension and higher fluid balance. Prevention of bleeding may reduce AKI in cardiac surgery.

Cardiac Surgical Bleeding, Transfusion, and Quality Metrics: Joint Consensus Statement by the Enhanced Recovery After Surgery Cardiac Society and Society for the Advancement of Patient Blood Management

BACKGROUND

Excessive perioperative bleeding is associated with major complications in cardiac surgery, resulting in increased morbidity, mortality, and cost.

METHODS

An international expert panel was convened to develop consensus statements on the control of bleeding and management of transfusion and to suggest key quality metrics for cardiac surgical bleeding. The panel reviewed relevant literature from the previous 10 years and used a modified RAND Delphi methodology to achieve consensus.

RESULTS

The panel developed 30 consensus statements in 8 categories, including prioritizing control of bleeding, prechest closure checklists, and the need for additional quality indicators beyond reexploration rate, such as time to reexploration. Consensus was also reached on the need for a universal definition of excessive bleeding, the use of antifibrinolytics, optimal cessation of antithrombotic agents, and preoperative risk scoring based on patient and procedural factors to identify those at greatest risk of excessive bleeding. Furthermore, an objective bleeding scale is needed based on the volume and rapidity of blood loss accompanied by viscoelastic management algorithms and standardized, patient-centered blood management strategies reflecting an interdisciplinary approach to quality improvement.

CONCLUSIONS

Prioritizing the timely control and management of bleeding is essential to improving patient outcomes in cardiac surgery. To this end, a cardiac surgical bleeding quality metric that is more comprehensive than reexploration rate alone is needed. Similarly, interdisciplinary quality initiatives that seek to implement enhanced quality indicators will likely lead to improved patient care and outcomes.

Definitions of major bleeding for predicting mortality in critically ill adult patients who survived 24 hours while supported with peripheral veno-arterial extracorporeal membrane oxygenation for cardiogenic shock: a comparative historical cohort study

PURPOSE

The severity of bleeding events is heterogeneously defined during peripheral veno-arterial extracorporeal membrane oxygenation (pVA-ECMO). We studied three bleeding definitions in pVA-ECMO: the Extracorporeal Life Support Organization (ELSO)-serious bleeding, the Bleeding Academic Research Consortium (BARC), and the universal definition of postoperative bleeding (UPDB) classifications.

METHODS

We included consecutive adult patients supported by pVA-ECMO for refractory cardiogenic shock admitted to Lille academic hospitals between January 2013 and December 2019. We assessed the association of bleeding definitions with the primary endpoint of 28-day all-cause mortality with the use of multivariate models accounting for time-dependent and competing variables. We compared models' performances using the Harrell's C-Index and the Akaike information criteria.

RESULTS

Twenty-eight-day mortality occurred in 128/308 (42%) 308 patients. The ELSO-serious bleeding (hazard ratio [HR], 1.67; 95% confidence interval [CI], 1.09 to 2.56) and BARC ≥ type 2 (HR, 1.55; 95% CI, 1.01 to 2.37) were associated with 28-day mortality (Harrell's C-index, 0.69; 95% CI, 0.63 to 0.74 for both). Predictors of ELSO-serious bleeding were postcardiotomy, body mass index, baseline platelets count, fibrinogen, and hemoglobin levels.

CONCLUSION

Extracorporeal Life Support Organization-serious bleeding and BARC ≥ type 2 are relevant definitions of major bleeding regarding their association with mortality in critically ill patients who survived the first 24 hr while supported with pVA-ECMO for cardiogenic shock.

STUDY REGISTRATION

CERAR (IRB 00010254-2022-050, Paris, France); first submitted on 18 April 2022.

Novel Platelet Function Analyzer 200 Predicts Blood Transfusion After Elective Cardiac Surgery in Patients Suspended on Dual Antiplatelet Therapy

The value of platelet function test in timing of cardiac surgery remains uncertain. Researches on correlation between Platelet Function Analyzer 200 (PFA-200) and bleeding after elective cardiac surgery are still inadequate. The objective of this study was to investigate the predictive value of PFA-200 in blood transfusion after cardiac surgery. A total of 71 patients on aspirin and P2Y12 receptor inhibitors undergoing cardiac surgery in Fuwai Hospital were enrolled. Platelet function after discontinuing of antiplatelet drugs was assessed by PFA-200 using closure time (CT). PFA-200 results before surgery were included in the statistics. The primary endpoint was postoperative blood transfusion. Seventeen patients (21.9%) received blood transfusion after cardiac surgery. The preoperative PFA-200 CT value in the transfused group was significantly higher than that in the non-transfused group (147.24 ± 85.54 s vs 98.06 ± 61.59 s, P = .011). Using 106 seconds as the dividing point, the incidence of blood transfusion in the elevated PFA-200 (CT > 106 s) group was significantly higher than those in normal PFA-200 (CT ≤ 106 s) group (10/24 patients, 41.9% vs 7/47 patients, 14.7%, P = .012). Multivariate logistic regression analysis showed that PFA-200 CT value > 106 s was an independent predictor of postoperative blood transfusion (OR: 4.05, 95%CI: 1.19-13.86, P = .026). The platelet function test PFA-200 had a predictive value for postoperative blood transfusion in elective cardiac surgery and had a promising prospect in the timing of cardiac surgery.

Machine learning algorithms to predict major bleeding after isolated coronary artery bypass grafting

Objectives

Postoperative major bleeding is a common problem in patients undergoing cardiac surgery and is associated with poor outcomes. We evaluated the performance of machine learning (ML) methods to predict postoperative major bleeding.

Methods

A total of 1,045 patients who underwent isolated coronary artery bypass graft surgery (CABG) were enrolled. Their datasets were assigned randomly to training (70%) or a testing set (30%). The primary outcome was major bleeding defined as the universal definition of perioperative bleeding (UDPB) classes 3–4. We constructed a reference logistic regression (LR) model using known predictors. We also developed several modern ML algorithms. In the test set, we compared the area under the receiver operating characteristic curves (AUCs) of these ML algorithms with the reference LR model results, and the TRUST and WILL-BLEED risk score. Calibration analysis was undertaken using the calibration belt method.

Results

The prevalence of postoperative major bleeding was 7.1% (74/1,045). For major bleeds, the conditional inference random forest (CIRF) model showed the highest AUC [0.831 (0.732–0.930)], and the stochastic gradient boosting (SGBT) and random forest models demonstrated the next best results [0.820 (0.742–0.899) and 0.810 (0.719–0.902)]. The AUCs of all ML models were higher than [0.629 (0.517–0.641) and 0.557 (0.449–0.665)], as achieved by TRUST and WILL-BLEED, respectively.

Conclusion

ML methods successfully predicted major bleeding after cardiac surgery, with greater performance compared with previous scoring models. Modern ML models may enhance the identification of high-risk major bleeding subpopulations.

Real-World Clinical and Economic Outcomes Associated with Surgiflo® vs Floseal in Cardiovascular Surgeries in the US

Background

Topical hemostatic agents are an option for controlling bleeding during cardiovascular surgery. Previous studies comparing topical hemostatic agents in cardiovascular surgery predate the 2012 reformulation of Surgiflo®, which had been re-engineered to increase paste viscosity and thus be more adherent to the bleeding surface.

Objective

To compare clinical and economic outcomes in patients receiving the current formulation of Surgiflo vs Floseal during cardiovascular surgeries.

Methodology

A retrospective analysis was conducted using the Premier Healthcare Database. Eligible patients had an inpatient cardiovascular surgery between 1/1/2013 and 6/1/2018, were ≥18 years old and received the current formulation of Surgiflo or Floseal during surgery. Propensity score matching was performed, with exact matching on the surgery year and surgery type (aortic, coronary artery bypass grafting, valve, or other). Descriptive analysis and generalized estimating equations models compared outcomes between the Surgiflo and Floseal groups.

Results

The matched sample included 5768 patients in each group (mean age: 66.5 years; 66.3% male). In the matched sample, rates of any documented bleeding event were similar in Surgiflo and Floseal groups (6.9% vs 7.2%; P = 0.576). Differences in transfusion rates between patients receiving Surgiflo vs Floseal varied by operational definition and timing of measurement but did not differ by >2 percentage points. Compared to Floseal, patients who received Surgiflo experienced longer surgery duration (306.0 vs 299.4 minutes), lower hospitalization cost ($44,146 vs $46,812), and lower odds of readmission at 30, 60, and 90 days post-discharge (all P < 0.05). Inpatient mortality and LOS were comparable between Surgiflo and Floseal (all P > 0.05).

Conclusion

In this large study of real-world clinical and economic outcomes after cardiovascular surgery involving the current formulation of Surgiflo vs Floseal, Surgiflo was associated with mostly similar clinical outcomes as compared with Floseal. Differences in selected economic/resource use outcomes were also observed, for which root-cause analysis in future research would be informative.

A Blinded Randomized Trial Comparing Standard Activated Clotting Time Heparin Management to High Target Active Clotting Time and Individualized Hepcon HMS Heparin Management in Cardiopulmonary Bypass Cardiac Surgical Patients

Purpose: High-dose heparin has been suggested to reduce consumption coagulopathy.

Materials and Methods: In a randomized, blinded, prospective trial of patients undergoing elective, complex cardiac surgery with cardiopulmonary bypass, patients were randomized to one of three groups: 1) high-dose heparin (HH) receiving an initial heparin dose of 450 u/kg, 2) heparin concentration monitoring (HC) with Hepcon Hemostasis Management System (HMS; Medtronic, Minneapolis, MN, USA) monitoring, or 3) a control group (C) receiving a standard heparin dose of 300 u/kg. Primary outcome measures were blood loss and transfusion requirements.

Results: There were 269 patients block randomized based on primary versus redo sternotomy to one of the three groups from August 2001 to August 2003. There was no difference in operative bleeding between the groups. Chest tube drainage did not differ between treatment groups at 8 hours (median [25th percentile, 75th percentile] for control group was 321 [211, 490] compared to 340 [210, 443] and 327 [250, 545], p = 0.998 and p = 0.540, for HH and HC treatment groups, respectively). The percentage of patients receiving transfusion was not different among the groups.

Conclusion: Higher heparin dosing accomplished by either activated clot time or HC monitoring did not reduce 24-hour intensive care unit blood loss or transfusion requirements.

Failure to achieve a satisfactory cardiac outcome after isolated coronary surgery in low-risk patients

OBJECTIVES

This study aims to investigate the incidence and determinants of major early adverse events in low-risk patients undergoing isolated coronary artery bypass grafting (CABG).

METHODS

The multicentre E-CABG registry included 7352 consecutive patients who underwent isolated CABG from January 2015 to December 2016. Patients with an European System for Cardiac Operative Risk Evaluation (EuroSCORE) II of <2% and without any major comorbidity were the subjects of the present analysis.

RESULTS

Out of 2397 low-risk patients, 11 (0.46%) died during the index hospitalization or within 30 days from surgery. Five deaths were cardiac related, 4 of which were secondary to technical failures. We estimated that 8 out of 11 deaths were potentially preventable. Logistic regression model identified porcelain aorta [odds ratio (OR) 34.3, 95% confidence interval (CI) 1.3-346.3] and E-CABG bleeding grades 2-3 (OR 30.2, 95% CI 8.3-112.9) as independent predictors of hospital death.

CONCLUSIONS

Mortality and major complications, although infrequently, do occur even in low-risk patients undergoing CABG. Identification of modifiable causes of postoperative adverse events may be useful to develop preventative strategies to improve the quality of care of patients undergoing cardiac surgery.

CLINICAL TRIAL REGISTRATION

NCT02319083 (https://clinicaltrials.gov/ct2/show/NCT02319083).

Predictors of Hospital Readmission within 30 Days after Coronary Artery Bypass Grafting: Data Analysis of 2,272 Brazilian Patients

Introduction

In order to reduce readmission rates after coronary artery bypass grafting (CABG), its predictors should be known in different contexts. The objective of this study was to identify predictive factors of hospital readmission within 30 days after CABG in a Brazilian center.

Methods

A secondary analysis of an electronic database of patients submitted to isolated CABG was performed. The relationship between readmission within 30 days and demographic, anthropometric, clinical, and surgery-related characteristics was investigated by univariate analyses. Predictors were identified by multiple logistic regression.

Results

Data from 2,272 patients were included, with an incidence of readmission of 8.6%. The predictors of readmission were brown skin color (Beta=1.613; 95% confidence interval [CI] 1.047-2.458; P=0.030), African-American ethnicity (Beta=0.136; 95% CI 0.019-0.988; P=0.049), chronic kidney disease (Beta=2.214; 95% CI 1.269-3.865; P=0.005), postoperative use of blood products (Beta=1.515; 95% CI 1.101-2.086; P=0.011), chronic obstructive pulmonary disease (Beta=2.095; 95% CI 1.284-3.419; P=0.003), and use of acetylsalicylic acid (Beta=1.418; 95% CI 1.000-2.011; P=0.05). Preoperative antibiotic prophylaxis (Beta=0.742; 95% CI 0.5471.007; P=0.055) was marginally significant.

Conclusion

The predictors identified may support a closer postoperative follow-up and individualized planning for a safe discharge.

Predictive scores for major bleeding after coronary artery bypass surgery in low operative risk patients

BACKGROUND

Cardiac surgery is associated with perioperative bleeding and carries high risk of allogeneic blood transfusion. Recently new scores for prediction of severe bleeding have been developed. This study aims to compare the WILL-BLEED, CRUSADE, PAPWORTH, TRUST, TRACK and ACTION scores in predicting major bleeding after CABG in patients with low estimated operative risk.

METHODS

A multicenter observational study included 1391 patients who underwent isolated CABG from July 2015 to January 2018. We tested the hypothesis that the WILL-BLEED score, specifically designed for CABG, would perform at least as well as the CRUSADE, PAPWORTH, TRUST, TRACK and ACTION scores in predicting postoperative major bleeding in low operative risk patients. The primary endpoint was the performance of known bleeding risk scores after CABG. The secondary endpoint was the evaluation of in-hospital mortality.

RESULTS

Mean age was 68.2±9.4 years and median Euroscore II value was 1.69% (IQR 1.15-2.81%). Mean blood losses in the first 12 postoperative hours was 339.75 mL. Seventy-three (5.2%) subjects underwent administration of blood products. The rate of severe-massive bleeding according to UDPB grades 3-4 was 1.5%. WILL-BLEED, TRUST, TRACK and ACTION scores were significantly associated with severe postoperative bleeding. WILL-BLEED presented the best c-index (AUC: 0.658; 95% CI: 0.600,0.716). Reclassification analysis showed a worsening in sensitivity and significant negative reclassification of CRUSADE, PAPWORTH, TRACK and ACTION scores when compared with WILL-BEED. The combination of WILL-BLEED and TRUST scores improved the prediction ability (AUC: 0.673; 95% CI: 0.615-0.732). Overall in-hospital mortality was 1.65%. Early mortality in patients with severe versus no-severe bleeding was found to be 11.8% vs. 1.0% Severe bleeding (OR: 13.26; P value<0.001) was found to be significantly associated with early mortality.

CONCLUSIONS

Severe bleeding after CABG is a harmful event associated with adverse outcomes. WILL-BLEED Score has the better performance in predicting severe-massive bleeding after CABG. The TRUST Score, although suboptimal, represents a valuable alternative in this setting.

The Prognostic Significance of Different Bleeding Classifications in off-pump coronary artery bypass grafting

BACKGROUND

Perioperative bleeding during cardiac surgery are known to make patients susceptible to adverse outcomes and several bleeding classifications have been developed to stratify the severity of bleeding events. Further validation of different classifications was needed. The aim of present study was to validate and explore the prognostic value of different bleeding classifications in patients undergoing off-pump coronary artery bypass grafting (OPCAB).

METHODS

Data on baseline and operative characteristics of 3988 patients who underwent OPCAB in Beijing Anzhen Hospital from February 2008 to December 2014 were available. The primary endpoint was a composite of in-hospital death and nonfatal postoperative myocardial infarction (MI). The secondary endpoint was postoperative acute kidney injury (AKI). We explored the association of major bleeding defined by the European registry of Coronary Artery Bypass Grafting (E-CABG), Universal Definition of Perioperative Bleeding (UDPB), Bleeding Academic Research Consortium (BARC) classification and Study of Platelet Inhibition and Patient Outcomes (PLATO) with primary endpoints by multivariable logistic regression analysis and investigated their significance of adverse event prediction using goodness-of-fit tests of - 2 log likelihood.

RESULTS

In-hospital mortality was 1.23% (n = 49) and postoperative MI was observed in 4.76% (n = 190) of patients, AKI in 24.69% (n = 985). The incidence of the primary outcome was 5.99% (n = 239). Multivariable logistic regression analysis showed that BARC type 4 (OR = 2.64, 95% CI: 1.66-4.19, P < 0.001), UDPB class 4 (OR = 3.52, 95% CI: 2.05-6.02, P < 0.001) and E-CABG class 2-3 (class 2: OR = 2.24, 95% CI: 1.36-3.70, P = 0.001; class 3: OR = 12.65, 95% CI: 2.74-18.43, P = 0.002) bleeding but not PLATO bleeding were associated with an increased risk of in-hospital death and postoperative MI. Major bleeding defined by all the four classifications mentioned above was an independent risk factor of AKI after surgery. Inclusion of major bleeding defined by these four classifications improved the predictive performance of the multivariable model with baseline characteristics.

CONCLUSIONS

Bleeding assessed by BARC, E-CABG and UDPB classifications were significantly associated with poorer immediate outcomes. These classifications seemed to be valuable tool in the assessment of prognostic effect of perioperative bleeding.

Absence of perioperative excessive bleeding in on-pump coronary artery bypass grafting cases performed by residents

OBJECTIVES

On-pump coronary artery bypass grafting (CABG) is associated with elevated bleeding risk. Our aim was to evaluate the role of surgical experience in postoperative blood loss.

METHODS

A propensity score-matched analysis was employed to compare on-pump CABG patients operated on by residents and specialists. End points included drainage volume and bleeding severity, as assessed by the Universal Definition of Perioperative Bleeding in cardiac surgery and E-CABG scale.

RESULTS

A total of 212 matched pairs (c-statistics 0.693) were selected from patients operated on by residents (n = 294) and specialists (n = 4394) between October 2012 and May 2018. Patients did not differ in bleeding risk. There were no statistically significant differences in postoperative 6-, 12- and 24-h drainages between subjects operated on by residents and specialists, and there was no between-group difference in rethoracotomy or transfusion rate. There were no differences in Universal Definition of Perioperative Bleeding or E-CABG grades. In June 2018, after a median follow-up of 2.8 years (range 0.1-5.7 years), the overall survival was 94%, with no differences between the patients operated on by residents (95%) and specialists (92%) (P = 0.27).

CONCLUSIONS

Patients undergoing on-pump CABG, when operated on by a resident, are not exposed to an elevated bleeding risk, as compared with patients operated on by experienced surgeons.

In-hospital and mid-term outcomes in patients reoperated on due to bleeding following coronary artery surgery (from the KROK Registry)

OBJECTIVES

Surgical re-exploration due to postoperative bleeding that follows coronary artery surgery is associated with significant morbidity and mortality. The aim of this study was to assess a relationship between re-exploration, major postoperative complications, in-hospital mortality and mid-term outcomes in patients following coronary surgery, on the basis of nationwide registry data.

METHODS

We identified all consecutive patients enrolled in Polish National Registry of Cardiac Surgical Procedures (KROK Registry) who underwent isolated coronary surgery between January 2012 and December 2014. Preoperative data, major postoperative complications, hospital mortality and mid-term all-cause mortality were, respectively, analysed. Comparisons were performed in all patients, low-risk patients (EuroSCORE II < 2%, males, aged 60-70 years) and propensity-matched patients. The starting point for follow-up was the date of hospital discharge.

RESULTS

Among 41 353 analysed patients, 1406 (3.4%) underwent re-exploration. Reoperated patients had more comorbidities, more frequent major postoperative complications, higher in-hospital mortality (13.2% vs 1.8%, P < 0.001) and higher mid-term mortality in survivors (P < 0.001). In the low-risk population, 3.0% of patients underwent re-exploration. Reoperated low-risk patients and propensity-matched patients also had more frequent major postoperative complications and higher in-hospital mortality, but mid-term mortality in survivors was similar. In a multivariable analysis, re-exploration was an independent predictor of death and all major postoperative complications.

CONCLUSIONS

Surgical re-exploration due to postoperative bleeding following coronary artery surgery carries a high risk of perioperative mortality and is linked to major postoperative complications. Among patients who survive to hospital discharge, mid-term mortality is associated primarily with preoperative comorbidities.

Prothrombin Complex Concentrate in Cardiac Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Prothrombin complex concentrate (PCC) has recently emerged as an effective alternative to fresh frozen plasma (FFP) in treating excessive perioperative bleeding. This systematic review and meta-analysis evaluated the safety and efficacy of PCC administration as first-line treatment for coagulopathy after adult cardiac surgery.

METHODS

PubMed/MEDLINE, EMBASE, and the Cochrane Library were searched from inception to the end of March 2018 to identify eligible articles. Adult patients undergoing cardiac surgery and receiving perioperative PCC were compared with patients receiving FFP.

RESULTS

A total of 861 adult patients from four studies were retrieved. No randomized studies were identified. Pooled odds ratios (ORs) showed that the PCC cohort was associated with a significant reduction in the risk of RBC transfusion (OR, 2.22; 95% confidence interval [CI], 1.45 to 3.40) and units of RBC received (OR, 1.34; 95% CI, 0.78 to 1.90). No differences were observed between the groups for reexploration for bleeding (OR, 1.09; 95% CI, 0.66 to 1.82), chest drain output at 24 hours (OR, 66.36; 95% CI, -82.40 to 216.11), hospital mortality (OR, 0.94; 95% CI, 0.59 to 1.49), stroke (OR, 0.80; 95% CI, 0.41 to 1.56), and occurrence of acute kidney injury (OR, 0.80; 95% CI, 0.58 to 1.12). A trend toward increased risk of renal replacement therapy was observed in the PCC group (OR, 0.41; 95% CI, 0.16 to 1.02).

CONCLUSIONS

In patients with significant bleeding after cardiac surgery, PCC administration seems to be more effective than FFP in reducing perioperative blood transfusions. No additional risks of thromboembolic events or other adverse reactions were observed. Randomized controlled trials are needed to establish the safety of PCC in cardiac surgery definitively.

Vitamin C to Improve Organ Dysfunction in Cardiac Surgery Patients-Review and Pragmatic Approach

The pleiotropic biochemical and antioxidant functions of vitamin C have sparked recent interest in its application in intensive care. Vitamin C protects important organ systems (cardiovascular, neurologic and renal systems) during inflammation and oxidative stress. It also influences coagulation and inflammation; its application might prevent organ damage. The current evidence of vitamin C's effect on pathophysiological reactions during various acute stress events (such as sepsis, shock, trauma, burn and ischemia-reperfusion injury) questions whether the application of vitamin C might be especially beneficial for cardiac surgery patients who are routinely exposed to ischemia/reperfusion and subsequent inflammation, systematically affecting different organ systems. This review covers current knowledge about the role of vitamin C in cardiac surgery patients with focus on its influence on organ dysfunctions. The relationships between vitamin C and clinical health outcomes are reviewed with special emphasis on its application in cardiac surgery. Additionally, this review pragmatically discusses evidence on the administration of vitamin C in every day clinical practice, tackling the issues of safety, monitoring, dosage, and appropriate application strategy.

Advances in critical care management of patients undergoing cardiac surgery

Cardiac surgery has been evolving to include minimally invasive, hybrid and transcatheter techniques. Increasing patient age and medical complexity means that critical care management needs to adapt and evolve. Recent advances have occurred in several areas, including ventilation, haemodynamics and mechanical circulatory support, bleeding and coagulation, acute kidney injury, and neurological management. This narrative review describes standard care, recent advances, and future areas of research in the critical care management of patients undergoing cardiac surgery.

Impact of major bleeding on the risk of acute kidney injury in patients undergoing off-pump coronary artery bypass grafting

Background

Patients with perioperative bleeding during cardiac surgery are susceptible to acute kidney injury (AKI) which is proposed to be associated with short-term and long-term risk of adverse events. The relationship between perioperative bleeding in off-pump coronary artery bypass grafting (OPCAB) and AKI remains unknown. The purpose of this study is to evaluate the impact of perioperative bleeding on the risk of postoperative AKI in patient undergoing OPCAB.

Methods

Perioperative major bleeding was defined by the universal definition of perioperative bleeding (UDPB) class 3 to 4. The primary endpoint was postoperative AKI which was diagnosed using criteria of stage 1 of AKI proposed by Acute Kidney Injury Network (AKIN). The secondary endpoints included in-hospital mortality and the incidence of postoperative myocardial infarction (MI). Baseline characteristics were compared between patients with and without major bleeding. Multivariable logistic regression analysis was performed to identify potential predictive factors for AKI after OPCAB.

Results

A total of 4,030 ACS (acute coronary syndrome) patients who underwent OPCAB were included in this study. Major bleeding rate was 9.8% (n =394). AKI was found in 995 (24.7%) patients. Multivariable regression analysis showed that perioperative major bleeding conferred a significantly higher risk of AKI after OPCAB with an odds ratio of 1.67 (95% confidence interval 1.32-2.10, P<0.001). When a decrease in hemoglobin, transfusion and chest tube output were included in the same logistic model separately to replace major bleeding, transfusion was the most strongly risk factor associated with AKI after surgery (OR =2.08, 95% CI: 1.38-3.16, P<0.001).

Conclusions

Perioperative bleeding is associated with a higher risk of postoperative AKI in ACS patients who underwent OPCAB. Moreover, blood and blood products transfusion most correlated with AKI after surgery. Prevention of severe bleeding and reducing blood transfusion requirement may improve the outcomes of OPCAB.

Short-term outcome of cardiac surgery under cardiopulmonary bypass in patients who refuse transfusion: a controlled study

BACKGROUND

Although bloodless cardiac surgery has been successfully performed for many years, studies with controls permitting transfusion are few and their results inconclusive. This study compares the outcome of cardiac surgery on Jehovah's Witnesses (JW) refusing transfusion, with that of controls permitting transfusion if required.

METHODS

Data from 172 operations in 162 JW were compared with 172 matched controls. Risk factors, preoperative, operative, 48 hour postoperative variables, outcome data and transfusions were recorded.

RESULTS

Preoperative and operative variables were similar in both groups except for more previous cardiac operations, and more frequent use of cell saver and aprotinin in JW, who bled less and had higher hemoglobin concentrations at all periods. Thirty-day mortality was higher in JW (9.9% vs. 3.5%; P=0.03) (Risk difference 6.4%; CI95%: 2.7-10.1). Nevertheless operative mortality was similar in both groups (9.9% vs. 7.6%; P=0.44). Mortality in low-risk subjects was higher in JW (8.9% vs. 1.0%; P=0.02) (Risk difference 7.9%; CI95%: 2.7-13.2). Moreover, death associated with hemorrhage and anemia tended to be more frequent in JW. Mortality of transfused controls (14.1%) and their matched JW (13.0%) was similar. In contrast, mortality of non-transfused controls was zero versus 6.3% in their matched JW (P=0.059).

CONCLUSIONS

Low-risk JW had significantly higher mortality than controls. Bleeding related deaths tended to be more frequent in JW. Blood-sparing maneuvers should be intensively implemented in both JW and patients permitting transfusion in order to reduce bleeding and the need for transfusion with its harmful effects.

The impact of minor blood transfusion on the outcome after coronary artery bypass grafting

PURPOSE

To investigate the impact of minor perioperative bleeding requiring transfusion of 1-2 red blood cell (RBC) units on the outcome after coronary artery bypass grafting (CABG).

METHODS

Sixteen cardiac surgical centers contributed to the prospective European CABG registry (E-CABG). 1014 patients receiving 1-2 RBC units during or after isolated CABG were compared to 2264 patients not receiving RBCs.

RESULTS

In 827 propensity score matched pairs, transfusion of 1-2 RBC units did not affect the risk of in-hospital/30-day death (p=0.523) or stroke (p=0.804). However, RBC transfusion was associated with an increased risk of acute kidney injury (p=0.008), sternal wound infection (p=0.001), postoperative use of antibiotics (p=0.001), prolonged use of inotropes (p<0.0001), use of intra-aortic balloon pump (p=0.012), length of intensive care unit stay (p<0.0001) and length of in-hospital stay (p<0.0001). Matched paired analysis excluding pre- and postoperative critical hemodynamic conditions showed that RBC transfusion was associated with an increased risk of major complications except in-hospital/30-day death.

CONCLUSION

Minor perioperative bleeding and subsequent transfusion of 1-2 RBC units did not affect the risk of early death, but increased the risk of other major adverse events. Minimizing perioperative bleeding and prevention of even low-volume RBC transfusion may improve the outcome after CABG.