Preoperative Anemia and Outcomes in Cardiovascular Surgery: Systematic Review and Meta-Analysis

Total arterial coronary artery bypass grafting in patients with preoperative anemia

OBJECTIVES

Blood transfusions after coronary artery bypass grafting (CABG) has been associated to adverse outcomes, especially in anemic patients. However, little is known about the influence of the modality of revascularization. Total arterial revascularization (TAR) was shown to reduce postoperative transfusion when compared to saphenous vein-based (SV)-CABG (LIMA plus one/more SV grafts). We, therefore, aimed to investigate the impact of TAR-CABG versus SV-CABG on blood products use and perioperative outcomes in patients with preoperative anemia, normally at higher risk for postoperative transfusions.

METHODS

From a cohort of 936 patients with mild preoperative anemia undergoing primary elective on-pump CABG, 166 matched pairs of patients undergoing either TAR- or SV-CABG were obtained. Anemia was defined as hemoglobin level <13 g/dl for men and <12 g/dl for women. The primary endpoint was the evaluation of red packed cells (RPC) use over the entire hospital stay.

RESULTS

TAR patients showed significantly reduced RPC usage compared with SV (mean difference 0.45 units). TAR patients had a reduced intubation time (mean difference 7.6 h) and were discharged 1.24 days earlier than SV patients. Pneumonia and acute kidney injury were doubled among SV patients. Adjusted regression showed that TAR technique is a predictor of reduced RPC unit use regardless of age and EuroSCORE II (odds ratio: 0.63, p < .01).

CONCLUSION

Patients with preoperative anemia might benefit from TAR regardless of age or calculated operative risk. TAR-CABG was associated to reduced postoperative use of blood products and postoperative length of stay in comparison with SV-CABG in this subset of patients.

Preoperative anaemia and outcome after elective cardiac surgery: a Dutch national registry analysis

BACKGROUND

Previous studies have shown that preoperative anaemia in patients undergoing cardiac surgery is associated with adverse outcomes. However, most of these studies were retrospective, had a relatively small sample size, and were from a single centre. The aim of this study was to analyse the relationship between the severity of preoperative anaemia and short- and long-term mortality and morbidity in a large multicentre national cohort of patients undergoing cardiac surgery.

METHODS

A nationwide, prospective, multicentre registry (Netherlands Heart Registration) of patients undergoing elective cardiac surgery between January 2013 and January 2019 was used for this observational study. Anaemia was defined according to the WHO criteria, and the main study endpoint was 120-day mortality. The association was investigated using multivariable logistic regression analysis.

RESULTS

In total, 35 484 patients were studied, of whom 6802 (19.2%) were anaemic. Preoperative anaemia was associated with an increased risk of 120-day mortality (adjusted odds ratio [aOR] 1.7; 95% confidence interval [CI]: 1.4-1.9; P<0.001). The risk of 120-day mortality increased with anaemia severity (mild anaemia aOR 1.6; 95% CI: 1.3-1.9; P<0.001; and moderate-to-severe anaemia aOR 1.8; 95% CI: 1.4-2.4; P<0.001). Preoperative anaemia was associated with red blood cell transfusion and postoperative morbidity, the causes of which included renal failure, pneumonia, and myocardial infarction.

CONCLUSIONS

Preoperative anaemia was associated with mortality and morbidity after cardiac surgery. The risk of adverse outcomes increased with anaemia severity. Preoperative anaemia is a potential target for treatment to improve postoperative outcomes.

Association of high-sensitivity C-reactive protein and anemia with acute kidney injury in neonates

BACKGROUND

The association of high-sensitivity C-reactive protein (hsCRP) and anemia with postoperative acute kidney injury (AKI) in neonates with congenital heart disease (CHD) is still unclear. The purpose of this study was to examine whether anemia-associated AKI is modulated by hsCRP in neonates.

METHODS

This study included 253 consecutive neonatal patients who underwent CHD surgery in a national tertiary hospital. We investigated the association between postoperative AKI with baseline hsCRP, anemia, and their interaction by multivariable logistic regression analyses.

RESULTS

The incidence of AKI was 24.1% in the entire cohort. After being adjusted for covariates, hsCRP level was negatively correlated with AKI (P < 0.01 for 1 mg/L threshold), whereas anemia emerged as an independent risk factor of AKI (P = 0.02). In addition, there was a significant interaction between anemia and hsCRP level (P = 0.01). In neonates with hsCRP < 1 mg/L, anemia was positively associated with AKI (P = 0.03). However, no significant association was found between anemia and AKI in the context of hsCRP ≥ 1 mg/L. Combination of anemia and hsCRP < 1 mg/L was independently correlated with the risk of AKI (P < 0.01), while concomitant anemia and hsCRP ≥ 1 mg/L or hsCRP < 1 mg/L combined with non-anemia was not.

CONCLUSIONS

In neonates with CHD, the risk of anemia-associated AKI may be modulated by hsCRP level. Attention should be paid to neonates with preoperative anemia and baseline hsCRP < 1 mg/L to reduce the risk of postoperative AKI.

Transfusion and its association with mortality in patients receiving veno-arterial extracorporeal membrane oxygenation

PURPOSE

Patients receiving veno-arterial Extracorporeal Membrane Oxygenation (V-A ECMO) may require transfusion due to bleeding risk and desire to optimize oxygen delivery. The purposes of this study were to determine the transfusion requirements in patients receiving V-A ECMO and to determine if transfusion was associated with hospital mortality or complications.

MATERIAL AND METHODS

Retrospective chart review of adult patients at University of Michigan between 1/1/2000-6/1/2017. Survivors and decedents were compared. Logistic regression was used to determine factors independently associated with mortality, hemorrhage, and ischemic events.

RESULTS

One hundred eighty-seven patients received V-A ECMO. Median number of red cells transfused was 9 units (interquartile range 3.5-20), platelets 4 (1-11) packs, plasma 2 (0-6) units, cryoprecipitate 0 (0,0) units. Only 69 (37%) patients survived to hospital discharge. Hemorrhage occurred in 108 (58%) patients and 27 (14%) suffered ischemic complications. Renal replacement therapy (OR 2.94, 95% confidence interval: 1.51-5.68, p < 0.001) and ECMO duration (OR 1.01, 95% confidence interval: 1.00-1.01, p = 0.005) but not transfusion, were associated with increased odds of death.

CONCLUSION

Most patients receiving V-A ECMO are transfused multiple units of blood products. Receipt of transfusion or having a bleeding or ischemic complication was not associated with increased mortality.

Anaemia: A risk factor for death and adverse outcomes following surgery for acute lower limb ischaemia

INTRODUCTION

Acute limb ischaemia (ALI) forms a significant part of the vascular surgery workload and carries with it high rates of morbidity and mortality. Anaemia is also common amongst vascular surgical patients and has been linked with poor outcomes in some subgroups. We aimed to assess the frequency of anaemia in patients with ALI and its impact on survival and complications following revascularisation to help direct future efforts to optimise outcomes in this patient group.

METHODS

A retrospective analysis of prospectively collected departmental data on patients undergoing surgical intervention for ALI between 2014 and 2018 was performed. Anaemia was defined as a pre-operative haemoglobin (Hb) of <120 g/L for women and <130 g/L for men. The primary outcome was overall survival, assessed with the Kaplan-Meier estimator, with application of Cox proportional hazard modelling to adjust for confounding covariates.

RESULTS

There were 158 patients who underwent treatment for ALI: 89 (56.3%) of these were non-anaemic with a mean Hb of 146 (SD = 18.4), and 69 (43.7%) were anaemic with a mean Hb of 106 (SD = 13.4). Anaemic patients had a significantly higher risk of death than their non-anaemic counterparts on univariate analysis (HR = 2.11, 95% CIs, 1.28-3.5, p = 0.0036). There was ongoing divergence in survival up to around 6 months between anaemic and non-anaemic groups. Under the Cox model, anaemia was similarly significant as a predictor of death (HR = 2.15, 95% CIs, 1.17-3.95, p = 0.013), accounting for recorded comorbidities, medication use and blood transfusion.

CONCLUSIONS

Anaemia is a significant and independent risk factor for death following revascularisation for ALI and can be potentially be modified. Vascular surgical centres should ensure they have robust pathways in place to identify and consider treating anaemia. There is scope for further work to assess how to best optimise a patient's levels of circulating haemoglobin.

[Results of implementation of a perioperative Patient Blood Management program in cardiovascular surgery]

BACKGROUND AND OBJECTIVE

Cardiovascular surgery (CCV) patients have a high incidence of perioperative anemia and bleeding that determines a high rate of allogeneic blood transfusion (AST). This is associated with an increase in morbidity, mortality and prolongs length of stay in hospital. Unnecessary transfusion is one of the measures to avoid and Patient Blood Management (PBM) programs have proven their effectiveness. Our objective was to reduce the transfusion of patients in cardiac surgery, without inferior results in morbidity and mortality, length of stay in hospital and being cost-effective, through the implementation of a PBM program.

MATERIAL AND METHODS

A mixed cohort study of 226 patients divided into 2 groups: retrospective pre-PBM (GP), from 2016, and intervention group (IG), prospective from 2018, with the results of the implementation of the guide.

RESULTS

The clinical results obtained allowed reducing the TSA from 92.59% to 79.69% (P<.001), saving 2.59 units of CH and 2.5 of PFC per patient (P<.001). A decrease was found in patients with fever (12.35% vs 1.56% with P=.006) and the need to escalate antibiotics (64.8% vs 42.19%, P=.002). The rest of postoperative complications and mortality at 3months did not present statistically significant differences. The length of stay was reduced by an average 3.6days in the IG, (95%CI: -8.10 to 0.9, P=.18). The cost decreased by 163.29€ per patient, taking into account exclusively the saving of blood components.

CONCLUSION

The PBM program is effective in reducing TSA in cardiac surgery in a tertiary hospital with high complexity patients and high transfusion rate. There are signs suggestive of a decrease in infections and a tendency to decrease the length of stay and mortality. In the economic approximation carried out, the cost of the intervention was lower than the savings implied by the decrease in transfusion.

Anemia as a Risk Factor for Organ Dysfunctions in Patients Operated on Heart Valves

Aim      To study the effects of pre- and postoperative anemia on the risk and the structure of internal organ dysfunction in patients undergoing surgery for acquired heart diseases (AHD).Material and methods  This was a retrospective cohort study including 610 primarily operated patients with AHD. A comparative analysis of the incidence and the structure of internal organ dysfunction was performed, and the likelihood of intraoperative hemotransfusion was determined for patients with preoperative anemia (Hb &lt;130 g/l) and without it. The incidence and the nature of internal organ damage were compared in patients with postoperative Hb &lt; 90 g/l and 90-130 g/l.Results The presence of postoperative anemia detected in 45 % of patients at two days after the surgery 6-fold increased the risk of acute heart failure (odds ratio [OR], 5.75; 95 % confidence interval [CI], 1.23-26.84; р=0.016), 4-fold increased the risk of multiorgan failure (MOF) (OR, 4.2; 95 % CI, 1.16-15.64; р=0.03), and 5-fold increased the likelihood of hemotransfusion (OR, 4.74; 95 % CI, 3.12-7.19; р&lt;0.0001). Severe and moderate anemia (Hb &lt;90 g/l) was observed in 11.2 % of patients, which presence 6-fold increased the risk of brain dysfunction (OR, 5.72; 95 % CI, 2.17-15.06; р=0.001) and MOF (OR, 5.97; 95 % CI, 1.94-18.35; р=0.004) compared to patients with Hb 90-130 g/l.Conclusion      In patients with AHD, postoperative anemia increases the risk of circulatory decompensation at two days after the surgery and of MOF and also increases the likelihood of intraoperative hemotransfusion; postoperative anemia with Hb &lt;90 g/l increases the risk of brain damage and MOF.

Postoperative infection and mortality following elective surgery in the International Surgical Outcomes Study (ISOS)

BACKGROUND

Postoperative infection is one of the most frequent and important complications after surgery. The epidemiology of infection following elective surgery remains poorly described.

METHODS

This was a prospective analysis of the International Surgical Outcomes Study (ISOS) describing infection by 30 days after elective surgery. Associations between postoperative infection (primary outcome) and baseline demographic, surgical, and anaesthetic risk factors were assessed. Analyses were carried out using logistic and linear regression models. Secondary outcomes were 30-day mortality and duration of hospital stay. Treatments received by patients after different types of infection were evaluated.

RESULTS

Some 44 814 patients were included in the analysis, with a total of 4032 infections occurring in 2927 patients (6.5 per cent). Overall, 206 patients died, of whom 99 of 2927 (3.4 per cent) had infection. Some 737 of 4032 infections (18.3 per cent) were severe; the most frequent types were superficial surgical-site infection (1320, 32.7 per cent), pneumonia (708, 17.6 per cent), and urinary tract infection (681, 16.9 per cent). Excluding missing data, antimicrobials were used in 2126 of 2749 infections (77.3 per cent), and 522 of 2164 patients (24.1 per cent) required admission to critical care. Factors associated with an increased incidence of infection in adjusted analyses were: age, male sex, ASA grade, co-morbid disease, preoperative anaemia, anaesthetic technique, surgical category, surgical severity, and cancer surgery. Infection significantly increased the risk of death (odds ratio 4.68, 95 per cent c.i. 3.39 to 6.47; P < 0.001), and duration of hospital stay by on average 6.45 (6.23 to 6.66) days (P < 0.001).

CONCLUSION

Infection is a common complication after elective surgery. Recognition of modifiable risk factors will help inform appropriate prevention strategies.

Preoperative anemia and transfusion in cardiac surgery: a single-centre retrospective study

Background

Preoperative anemia and transfusion are associated with worse outcomes. This study aims to identify the prevalence of preoperative anemia, transfusion rates on surgery day, and predictors of transfusion in elective cardiac surgery patients at our centre. We also aim to evaluate our preoperative intervention program, and examine the intervention window for anemia before surgery.

Methods

This study included 797 adult patients who underwent elective cardiac surgery at a tertiary hospital. Multivariable logistic regression analysis was used to identify predictors of transfusion on surgery day.

Results

Preoperative anemia was present in 15% of patients. Anemic patients had a significantly higher transfusion rate at 53% compared to 10% in non-anemic patients. Hemoglobin concentration, estimated glomerular filtration rate (eGFR), body surface area (BSA), and total cardiopulmonary bypass time were predictive of transfusion on surgery day. Patients had a median of 7 days between initial visit and surgery day, however, referral to the blood conservation clinic was only done for 8% of anemic patients and treatment was initiated in 3% of anemic patients. Among the 3 anemic patients who received treatment, 2 did not require blood transfusion on surgery day.

Conclusions

Preoperative anemia is present in 15% of patients at our centre and these patients have 53% transfusion rates on surgery day. Hemoglobin concentration, eGFR, BSA, and total cardiopulmonary bypass time were predictors of transfusion on surgery day. Patients had a median of 7 days between initial visit and surgery day. Referral and anemia treatment were infrequently initiated in preoperative anemic patient.

Sex-Specific Associations Between Preoperative Anemia and Postoperative Clinical Outcomes in Patients Undergoing Cardiac Surgery

BACKGROUND

Preoperative anemia is common in cardiac surgery, yet there were limited data describing the role of sex in the associations between anemia and clinical outcomes. Understanding these relationships may guide preoperative optimization efforts.

METHODS

This is an observational cohort study of adults undergoing isolated coronary artery bypass grafting or single- or double-valve surgery from 2008 to 2018 at a large tertiary medical center. Multivariable regression assessed the associations between preoperative hemoglobin concentrations and a primary outcome of postoperative acute kidney injury (AKI) and secondary outcomes of perioperative red blood cell (RBC) transfusion, reoperation, vascular complications (ie, stroke, pulmonary embolism, and myocardial infarction), and hospital length of stay (LOS). Each outcome was a single regression model, using interaction terms to assess sex-specific associations between hemoglobin and outcome.

RESULTS

A total of 4117 patients were included (57% men). Linear splines with sex-specific knots (13 g/dL in women and 14 g/dL in men) provided the best overall fit for preoperative hemoglobin and outcome relationships. In women, each 1 g/dL decrease in hemoglobin <13 g/dL was associated with increased odds of AKI (odds ratio = 1.49; 95% confidence interval [CI], [1.23-1.81]; P < .001), and there was no significant association between hemoglobin per 1 g/dL >13 g/dL and AKI (0.90 [0.56-1.45]; P = .67). The association between hemoglobin and AKI in men did not meet statistical significance (1.10 [0.99-1.22]; P = .076, per 1 g/dL decrease <14 g/dL; 1.00 [0.79-1.26]; P = .98 for hemoglobin per 1 g/dL >14 g/dL). In women, lower preoperative hemoglobin (per 1 g/dL decrease <13 g/dL) was associated with increased odds of RBC transfusion (2.90 [2.33-3.60]; P < .001), reoperation (1.27 [1.11-1.45]; P < .001) and a longer hospital LOS (multiplicative increase in geometric mean 1.05 [1.03-1.07]; P < .001). In men, preoperative hemoglobin (per 1 g/dL decrease <14 g/dL) was associated with increased odds of perioperative RBCs (2.56 [2.27-2.88]; P < .001) and longer hospital LOS (multiplicative increase in geometric mean 1.02 [1.01-1.04] days; P < .001) but not reoperation (0.94 [0.85-1.04]; P = .256). Preoperative hemoglobin per 1 g/dL >13 g/dL in women and 14 g/dL in men were associated with lower odds of RBCs transfusion (0.57 [0.47-0.69]; P < .001 and 0.74 [0.60-0.91]; P = .005, respectively).

CONCLUSIONS

Preoperative anemia was associated with inferior clinical outcomes after cardiac surgery. The associations between hemoglobin and outcomes were distinct for women and men, with different spline knot points identified (13 and 14 g/dL, respectively). Clinicians should consider data-driven approaches to determine preoperative hemoglobin values associated with increasing risk for adverse perioperative outcomes across sexes.

Guidelines for enhanced recovery after cardiac surgery. Consensus document of Spanish Societies of Anesthesia (SEDAR), Cardiovascular Surgery (SECCE) and Perfusionists (AEP)

The ERAS guidelines are intended to identify, disseminate and promote the implementation of the best, scientific evidence-based actions to decrease variability in clinical practice. The implementation of these practices in the global clinical process will promote better outcomes and the shortening of hospital and critical care unit stays, thereby resulting in a reduction in costs and in greater efficiency. After completing a systematic review at each of the points of the perioperative process in cardiac surgery, recommendations have been developed based on the best scientific evidence currently available with the consensus of the scientific societies involved.

Preoperative Anemia and Outcomes After Corrective Surgery in Neonates With Dextro-Transposition of the Great Arteries

OBJECTIVES

The authors aimed to assess whether untreated preoperative anemia was associated with increased risk for adverse outcomes after the arterial switch operation in neonates with dextro-transposition of the great arteries (d-TGA).

DESIGN

Retrospective cohort study.

SETTING

Single cardiac surgery center.

PARTICIPANTS

Eighty-two newborns with d-TGA.

INTERVENTIONS

The authors categorized the cohort into the following two groups: the infants with preoperative anemia group (defined as a hematocrit <0.40 L/L) and the control group.

MEASUREMENTS AND MAIN RESULTS

Preoperative anemia was diagnosed in 21 (25.6%) infants. Anemic infants received intraoperative red blood cell transfusions significantly more often than controls (81.0% v 34.4%, p < 0.001). No differences were observed in the incidence of adverse events, duration of hospitalization (median 27 days v 26 days, p = 0.881), and mortality (0% v 4.9%, p = 0.566). Postnatal hematocrit was the only variable independently associated with preoperative anemia in multivariate logistic regression analysis (unit odds ratio, 0.832; 95% confidence interval, 0.743-0.931; p = 0.001).

CONCLUSIONS

Untreated preoperative anemia was not associated with adverse outcomes in neonates undergoing reparative surgery for d-TGA.

Postoperative Nadir Hemoglobin and Adverse Outcomes in Patients Undergoing On-Pump Cardiac Operation

BACKGROUND

Patients undergoing cardiac operation are susceptible to anemia. Low hemoglobin concentration is a risk factor for composite adverse events and death after cardiac operation. Here we investigated the association of postoperative nadir hemoglobin with adverse outcomes in patients undergoing on-pump cardiac operation.

METHODS

Adult patients in 2 medical centers were retrospectively analyzed. The primary outcome was postoperative composite adverse events. The secondary outcome was all-cause death in the hospital.

RESULTS

Of the 8206 patients analyzed, 1628 (19.8%) experienced composite adverse events after operation and 109 (1.3%) died. Patients receiving on-pump cardiac operation with nadir hemoglobin of 9.0 to 9.9 g/L showed a low incidence of composite adverse events (175 of 1423 [12.3%]) and death (5 of 1423 [0.4%]). Compared with nadir hemoglobin at 9.0 to 9.9 g/dL, the relative risk (RR) of composite adverse events increased stepwise as nadir hemoglobin fell below 9.0 g/dL: adjusted RR was 1.44 (95% confidence interval [CI], 1.14-1.83) for 8.5 to 8.9 g/dL, 1.56 (95% CI, 1.23-1.99) for 8.0 to 8.4 g/dL, 1.66 (95% CI, 1.31-2.11) for 7.5 to 7.9 g/dL, 2.22 (95% CI, 1.75-2.83) for 7.0 to 7.4 g/dL, and 4.00 (95% CI, 3.18-5.04) for less than 7 .0 g/dL. Furthermore, the risk of death was significantly higher when nadir hemoglobin was below 7.0 g/dL than when it was 9.0 to 9.9 g/dL (RR, 5.36; 95% CI, 2.20-16.12).

CONCLUSIONS

Compared with the risks when nadir hemoglobin is 9.0 to 9.9 g/dL, the risk of composite adverse events increases when postoperative nadir hemoglobin is below 9.0 g/dL, whereas risk of death increases when nadir hemoglobin is below 7.0 g/dL.

Preoperative Hemoglobin Level, Oxygen Saturation and Postoperative Outcomes in Children With Cyanotic Congenital Heart Disease: A Propensity-Score Matching Analysis

BACKGROUND

The optimal preoperative hemoglobin (Hb) level is difficult to define in children with cyanotic congenital heart disease (CHD) due to hypoxemia-induced secondary erythrocytosis. This retrospective study integrated preoperative Hb and pulse oxygen saturation (SpO₂) using the product of Hb × SpO₂ to predict postoperative outcomes in children with cyanotic CHD.

PATIENTS AND METHODS

Children aged <18 years undergoing cardiac surgery with cyanotic CHD were included. The cutoff value of Hb × SpO₂ was the age-adjusted lower limit of normal Hb (aaHb) in healthy children. The main outcomes were in-hospital death and the composite outcome of severe postoperative events. Multivariate logistic regression analysis and propensity score matching analysis were used to adjust for important confounders.

RESULTS

The presence of preoperative Hb × SpO₂ < aaHb was observed in 21.6% of cyanotic children (n = 777). Children with Hb × SpO₂ < aaHb had higher in-hospital mortality (12.5% vs. 4.6%, P < 0.001) and composite outcome incidence (69.6% vs. 32.3%, P < 0.001) than those with Hb × SpO₂ ≥ aaHb. After propensity score matching, 141 pairs of children were successfully matched. Multivariate analysis showed that preoperative Hb × SpO₂ < aaHb was significantly associated with the composite outcome in the entire population (odds ratio = 4.092, 95% confidence interval = 2.748-6.095, P < 0.001) and the matched cohorts (odds ratio = 2.277, 95% confidence interval = 1.366-3.795, P = 0.002).

CONCLUSION

Our results suggest that a preoperative Hb × SpO₂ value below the lower limit of normal hemoglobin is a prognostic factor in cyanotic children undergoing cardiac surgery and is a potential criterion to evaluate preoperative anemia in this population.

Management of Perioperative Iron Deficiency in Cardiac Surgery: A Modified RAND Delphi Study

BACKGROUND

Over the last decade, preoperative anemia has become recognized as a clinical condition in need of management. Although the etiology of preoperative anemia can be multifactorial, two-thirds of anemic elective surgical patients have iron deficiency anemia. At the same time, one-third of non-anemic elective surgical patients are also iron deficient.

METHODS

Modified-RAND Delphi methodology was employed to identify areas of consensus among an expert panel regarding the management of iron deficiency in patients undergoing cardiac surgery. A list of statements was sent to panel members to respond to using a five-point Likert Scale. All panel members subsequently attended a face-to-face meeting. The initial survey was presented and discussed, and panel members responded to each statement on the Likert scale again. Based on the second survey, the panel came to a consensus on recommendations.

RESULTS

The panel recommended all patients undergoing cardiac surgery be evaluated for iron deficiency, whether or not anemia is present. Evaluation should include iron studies and reticulocyte hemoglobin content. If iron deficiency is present, with or without anemia, patients should receive parenteral iron. Erythropoietin stimulating agents may be appropriate for some patients.

CONCLUSIONS

Consensus of an expert panel resulted in a standardized approach to diagnosing and managing iron deficiency in patients undergoing cardiac surgery.

[Anemia as a risk factor of contrast-associated acute kidney injury]

AIM

The aim of our study was to assess the role of anemia as a risk factor of contrast-associated acute kidney injury (CA-AKI) in patients with stable coronary artery disease.

MATERIALS AND METHODS

1023 patients with chronic coronary artery disease were enrolled in a prospective, open, cohort study (ClinicalTrials.gov ID NCT04014153). 83 patients had anemia. CA-AKI was defined as an increase of 25% or more, or an absolute increase of 0.5 mg/dl or more in serum creatinine from baseline value, assessed at 48 hours following the administration of the contrast. The primary endpoint of the study was the development of CA-AKI according to KDIGO criteria.

RESULTS

CA-AKI developed in 12 (14.5%) patients with anemia according to the relative increase of the level of serum creatinine (25% and more from the baseline). With using the absolute increase of the level of serum creatinine the prevalence of CA-AKI was 2 (2.4%) patients. Patients with anemia had higher rate of CA-AKI than the overall population of the study (14.4% versus 12.7%). Although our results were not statistically significant (р=0.61, odds ratio 1.19, 95% confidence interval 0.632.24).

CONCLUSION

The prevalence of CA-AKI was higher in the group of patients with anemia, but didnt meet statistical significance and needs further evaluation in larger studies.

The Impact of Transfusions on Mortality After Transcatheter or Surgical Aortic Valve Replacement

BACKGROUND

An increasing body of evidence suggests that packed red blood cell (PRBC) transfusion may be associated with increased morbidity and mortality after transcatheter and surgical aortic valve replacement. It remains unclear whether PRBC transfusion is a surrogate marker or truly an independent risk factor for mortality after aortic valve replacement in different populations.

METHODS

The Surgical Replacement and Transcatheter Aortic Valve Implantation (SURTAVI) trial randomized 1660 patients with symptomatic, severe aortic stenosis at intermediate risk for operative death to transcatheter aortic valve replacement or surgical aortic valve replacement. Baseline characteristics and outcomes including all-cause and cardiovascular mortality at 30 days and thereafter were compared between participants with and participants without PRBC transfusion. Cox proportional hazards models with time-varying covariates were fitted to estimate the effect of PRBC transfusion on mortality after adjustment for comorbidities and procedural complications.

RESULTS

Patients receiving PRBC were older, more commonly female and frail, with more comorbidities. The Society of Thoracic Surgeons Predicted Risk of Mortality baseline score was higher in the transfused group. After adjustment for these differences, PRBC transfusion was associated with mortality at 30 days, but not thereafter. The effect of PRBC on mortality (hazard ratio 1.04; 95% confidence interval, 0.96 to 1.11; P = .304) at 30 days was not independent of procedural complications (hazard ratio 21.04; 95% CI, 7.26 to 60.95; P < .001).

CONCLUSIONS

Poor health status, procedural complications, PRBC transfusion, and mortality are correlated with each other. Transfusion of PRBC did not independently increase risk for mortality. In this intermediate-risk population, transfusion appears to be a risk marker of chronic conditions and periprocedural complications as opposed to a risk factor for postprocedural mortality. (Clinical trial registration: www.clinicaltrials.gov NCT01586910.).

Preoperative atrial fibrillation in association with reduced haemoglobin predicts increased 30-d mortality after cardiac surgery

OBJECTIVES

Atrial fibrillation is the most common arrhythmia occurring after cardiac surgery. Less attention has been focused on preoperative atrial fibrillation and anaemia as risk factors for mortality after cardiac surgery. The aim of this study was to determine preoperative risk factors for 30-d mortality after open-heart surgery. Design. The study population consisted of 2015 patients (73.4% men; mean age 68 years) undergoing coronary artery bypass grafting (CABG) (52.0%), aortic valve replacement (AVR) (18.6%), AVR and CABG (10.0%), mitral valve plasty or replacement (14.0%), and AVR and aortic root reconstruction (ARR) (5.5%) in Kuopio University Hospital from January 2013 to December 2016. Univariate and multivariate Cox proportional hazards models were used for statistical analyses. Kaplan-Meier survival curves were generated. Results. Total 30-d mortality was 1.8%. By Cox regression analysis, predictors of 30-d mortality (hazard ratio [HR] [95% confidence interval [CI]]) included female gender (1.95 [1.00-3.77]), preoperative atrial fibrillation, (2.38 [1.12-5.03]) reduced haemoglobin level (3.40 [1.47-7.90]), and pulmonary congestion (3.16 [1.52-6.55]). The combination of preoperative reduced haemoglobin and preoperative atrial fibrillation was a strong predictor (12.37 [4.40-34.77], p < .001). Estimated glomerular filtration rate (eGFR) predicted 30-d mortality in univariate models but was not an independent predictor in multivariate models. Conclusions. According to the main findings of our study, the combination of preoperative atrial fibrillation and reduced haemoglobin level substantially increase the risk of 30-d mortality after cardiac surgery. Identification of high-risk patients pre-operatively could help to make optimal clinical decisions for timing of operation and perioperative treatment.

Controversies in the Clinical Practice of Patient Blood Management

Patient blood management (PBM) has been proposed as a standard of care in modern perioperative medicine. PBM-related interventions usually are implemented as bundles, but randomized controlled trials on the implementation of PBM as a bundle are missing. This special article focuses on the current evidence and controversies in the clinical practice of PBM and on emerging data related to specific PBM-related interventions in patients undergoing cardiac surgery. Strong evidence for many PBM-related interventions is limited because of missing studies or the poor quality of published findings and study endpoints. Restrictive blood transfusion and timely interventions to maintain hemoglobin concentration and to reduce blood loss potentially might result in improved patient outcome, although the latter has yet to be proven.

Preoperative Anemia as a Risk Factor for Postoperative Outcomes in Patients Undergoing Lung Transplantation

OBJECTIVES

The aim of this study was to evaluate the effect of preoperative anemia on early postoperative outcomes in a population of patients undergoing lung transplantation.

DESIGN

Single-center retrospective study of lung transplantation recipients between April 2013 and June 2018. The primary outcome was hospital length of stay.

SETTING

Ronald Reagan UCLA Medical Center, Los Angeles, CA, a tertiary academic medical center.

PARTICIPANTS

Patients presenting from home for lung transplantation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 435 patients underwent lung transplantation during the study period. After exclusion, 342 were included in the analysis. The prevalence of preoperative anemia was 54% (n = 183); however, only 11% of anemic patients received treatment for anemia before transplantation. Multivariate regression analysis indicated that lower hemoglobin levels were associated with longer hospital lengths of stay (p = 0.049). Preoperative anemia also was independently associated with an increased risk for redo surgery for bleeding (odds ratio 4.89; p = 0.007). No association between preoperative anemia and any of the other postoperative outcomes examined was found.

CONCLUSIONS

Preoperative anemia in patients undergoing lung transplantation is undertreated and independently associated with an increased risk for redo surgery for bleeding. Additional studies regarding reasons for this association and effect of treatment are necessary to improve outcomes.

A Better Predictor of Acute Kidney Injury After Cardiac Surgery: The Largest Area Under the Curve Below the Oxygen Delivery Threshold During Cardiopulmonary Bypass

Background

The aim of this study was to compare the predictive accuracy of acute kidney injury (AKI) after cardiac surgery using cardiopulmonary bypass for the largest area under the curve (AUC) below the oxygen delivery (DO₂) threshold and the cumulative AUC below the DO₂ threshold.

Methods and Results

From March 2017 to October 2019, 202 patients who had undergone cardiac surgery with cardiopulmonary bypass were enrolled. The perfusion parameters were recorded every 20 seconds, and the DO₂ (10×pump flow index [L/min per m²]×[hemoglobin (g/dL)×1.36×arterial oxygen saturation (%)+partial pressure of arterial oxygen (mm Hg)×0.003]) threshold of 300 mL/min per m² was considered to define sufficient DO₂. The nadir DO₂, the cumulative AUC below the DO2300, and the largest AUC below the DO2300 were used to predict the incidence of AKI. Postoperative AKI was observed in 12.4% of patients (25/202). By multivariable analysis, the largest AUC below the DO2300 ≥880 (odds ratio [OR], 4.9; 95% CI, 1.2–21.5 [P=0.022]), preoperative hemoglobin concentration ≤11.6 g/dL (OR, 7.6; 95% CI, 2.0–32.3 [P=0.004]), and red blood cell transfusions during cardiopulmonary bypass ≥2 U (OR, 3.3; 95% CI, 1.0–11.1 [P=0.041]) were detected as independent risk factors for AKI. Receiver operating curve analysis revealed that the largest AUC below the DO2300 was more accurate to predict postoperative AKI compared with the nadir DO₂ and the cumulative AUC below the DO2300 (differences between areas, 0.0691 [P=0.006] and 0.0395 [P=0.001]).

Conclusions

These data suggest that a high AUC below the DO2300 is an important independent risk factor for AKI after cardiopulmonary bypass, which could be considered for risk prediction models of AKI.

Anemia and perioperative mortality in non-cardiac surgery patients: a secondary analysis based on a single-center retrospective study

Background

Evidence regarding the relationship between anemia and perioperative prognosis is controversial. The study was conducted to highlight the specific relationship between anemia and perioperative mortality in non-cardiac surgery patients over 18 years of age.

Methods

This study was a retrospective analysis of the electronic medical records of 90,784 patients at the Singapore General Hospital from January 1, 2012 to October 31, 2016. Multivariate regression, propensity score analysis, doubly robust estimation, and an inverse probability-weighting model was used to ensure the robustness of our findings.

Results

We identified 85,989 patients, of whom75, 163 had none or mild anemia (Hemoglobin>90g/L) and 10,826 had moderate or severe anemia (Hemoglobin≤90g/L). 8,857 patients in each study exposure group had similar propensity scores and were included in the analyses. In the doubly robust model, postoperative 30-day mortality rate was increased by 0.51% (n = 219) in moderate or severe anemia group (Odds Ratio, 1.510; 95% Confidence Interval (CI), 1.049 to 2.174) compared with none or mild anemia group (2.47% vs.1.22%, P<0.001). Moderate or severe anemia was also associated with increased postoperative blood transfusion rates (OR, 5.608; 95% CI, 4.026 to 7.811, P < 0.001). There was no statistical difference in Intensive Care Unit (ICU) admission rate among different anemia groups within 30 days after surgery (P=0.104).

Discussion

In patients undergoing non-cardiac surgery over 18 years old, moderate or severe preoperative anemia would increase the occurrence of postoperative blood transfusion and the risk of death, rather than ICU admission within 30 days after surgery.

Efficacy of quadruple treatment on different types of pre-operative anaemia: secondary analysis of a randomised controlled trial

In patients with pre-operative anaemia undergoing cardiac surgery, combination treatment with intravenous iron, subcutaneous erythropoietin alpha, vitamin B12 and oral folic acid reduces allogeneic blood product transfusions. It is unclear if certain types of anaemia particularly benefit from this treatment. We performed a post-hoc analysis of anaemic patients from a randomised trial on the 'Effect of ultra-short-term treatment of patients with iron deficiency or anaemia undergoing cardiac surgery'. We used linear regression analyses to examine the efficacy of a combination anaemia treatment compared with placebo on the following deficiencies, each representing a part of the combination treatment: ferritin and transferrin saturation; endogenous erythropoietin; holotranscobalamine; and folic acid in erythrocytes. Efficacy was defined as change in reticulocyte count from baseline to the first, third and fifth postoperative days and represented erythropoietic activity in the immediate peri-operative recovery phase. In all 253 anaemic patients, iron deficiency was the most common cause of anaemia. Treatment significantly increased reticulocyte count in all regression analyses on postoperative days 1, 3 and 5 (all p < 0.001). Baseline ferritin and endogenous erythropoietin were negatively associated with change in reticulocyte count on postoperative day 5, with an unstandardised regression coefficient B of -0.08 (95%CI -0.14 to -0.02) and -0.14 (95%CI -0.23 to -0.06), respectively. Quadruple anaemia treatment was effective regardless of the cause of anaemia and its effect manifested early in the peri-operative recovery phase. The more pronounced a deficiency was, the stronger the subsequent boost to erythropoiesis may have been.

Single center experience with patients on veno arterial ECMO due to postcardiotomy right ventricular failure

OBJECTIVES

Right ventricular (RV) failure is associated with poor outcome and increased mortality in cardiac surgery. Aim of our study was to analyze the outcome of veno arterial extracorporeal membrane oxygenation (va ECMO) therapy in patients with isolated RV failure in postcardiotomy cardiogenic shock (PCS) and to evaluate risk factors associated with 30-day-mortality.

METHODS

Between August 2006 until August 2016, 64 consecutive patients with va ECMO therapy due to fulminant RV failure in PCS were identified and included in this retrospective observation. Further, outcome data and a comparison of va ECMO survivors and nonsurvivors was conducted.

RESULTS

The mean age of the patient cohort was 63 ± 14 years. Patients were treated with va ECMO for 79 ± 61 hours. Twenty-eight patients (44%) were successfully weaned off ECMO support. Overall 30-day-mortality was 88% (56/64). Hemoglobin concentration before ECMO implantation, maximum rise of muscle-brain type creatine kinase during ECMO therapy, as well as lactic acid concentration 24 hours after initiation of va ECMO therapy were predictive for 30-day mortality.

CONCLUSION

ECMO therapy in RV failure due to PCS is shown to be associated with an excessive mortality. Regarding our data, va ECMO might only be an appropriate short-term mechanical assist device separating patients form cardiopulmonary bypass with an acceptable weaning rate. Particularly, in case of failed hemodynamic recovery of the right heart on va ECMO, direct RV bypass systems might function as a bailout option. Additionally, cardiac enzymes and lactic acid might provide valuable information in meeting therapy-related decisions.