Pre-operative anaemia, intra-operative hepcidin concentration and acute kidney injury after cardiac surgery: a retrospective observational study

Postoperative intravenous iron to treat iron-deficiency anaemia in patients undergoing cardiac surgery: a protocol for a pilot, multicentre, placebo-controlled randomized trial (the POAM trial)

Background

Iron-deficiency anaemia, occurring in 30-40% of patients undergoing cardiac surgery, is an independent risk factor for adverse outcomes. Our long-term goal is to assess if postoperative i.v. iron therapy improves clinical outcomes in patients with preoperative iron-deficiency anaemia undergoing cardiac surgery. Before conducting a definitive RCT, we first propose a multicentre pilot trial to establish the feasibility of the definitive trial.

Methods

This internal pilot, double-blinded, RCT will include three centres. Sixty adults with preoperative iron-deficiency anaemia undergoing non-emergency cardiac surgery will be randomised on postoperative day 2 or 3 to receive either blinded i.v. iron (1000 mg ferric derisomaltose) or placebo. Six weeks after surgery, patients who remain iron deficient will receive a second blinded dose of i.v. iron according to their assigned treatment arm. Patients will be followed for 12 months. Clinical practice will not be otherwise modified. For the pilot study, feasibility will be assessed through rates of enrolment, protocol deviations, and loss to follow up. For the definitive study, the primary outcome will be the number of days alive and out of hospital at 90 days after surgery.

Ethics and dissemination

The trial has been approved by the University Health Network Research Ethics Board (REB # 22-5685; approved by Clinical Trials Ontario funding on 22 December 2023) and will be conducted in accordance with the Declaration of Helsinki, Good Clinical Practices guidelines, and regulatory requirements.

Clinical trial registration

NCT06287619.

Inflammatory Trajectory and Anti-Inflammatory Pharmacotherapy in Frozen Elephant Trunk-Treated Acute Type I Aortic Dissection

Background

Acute DeBakey type I aortic dissection is associated with high morbidity and mortality. Little is known regarding the role of leukocyte trajectory in prognosis.

Methods

We included adult acute DeBakey type I aortic dissection patients with emergency frozen elephant trunk and total arch replacement in 2 cardiovascular centers (2020-2022). We used latent class mixed model to group patients according to their leukocyte patterns from hospital admission to the first 5 days after surgery. We investigated the association of leukocyte trajectory and 30-day and latest follow-up mortality (October 31, 2023), exploratorily analyzing the effects of ulinastatin treatment on outcome.

Results

Of 255 patients included, 3 distinct leukocyte trajectories were identified: 196 in group I (decreasing trajectory), 34 in group II (stable trajectory), and 25 in group III (rising trajectory). Overall, 30-day mortality was 25 (9.8%), ranging from 8.2% (16/196) in group I, 8.8% (3/34) in group II, to 24.0% (6/25) in group III (P for trend = .036). Group III was associated with higher mortality both at 30 days (adjusted hazard ratio, 3.260; 95% CI, 1.071-9.919; P = .037) and at the last follow-up (adjusted hazard ratio, 2.840; 95% CI, 1.098-7.345; P = .031) compared with group I.

Conclusions

Distinct and clinically relevant groups can be identified by analyzing leukocyte trajectories, and a rising trajectory was associated with higher short-term and midterm mortality.

[Iron deficiency in cardiac surgery patients and the possibility of its correction at the preoperative stage]

Among cardio-surgical patients, the prevalence of iron deficiency conditions reaches 70 %, and anemia is detected in less than 50% cases. Meanwhile, both anemia and latent iron deficiency are risk factors for adverse outcomes in cardio-surgical patients. These conditions are associated with a high frequency and greater volume of blood transfusions as well as with a longer stay in the hospital. Timely diagnosis and correction of iron deficiency, regardless of the presence of anemia, are mandatory at the stage of preoperative preparation. The use of oral iron medicines is limited by their low efficacy in this category of patients and a high risk of adverse events. Intravenous iron medicines have a high potential for correcting iron deficiency, and their efficacy and safety have been previously demonstrated. Administration of ferric carboxymaltose has proved beneficial in studies on iron deficiency correction in cardiological and cardio-surgical patients. In these patients, ferric carboxymaltose improved the dynamics of ferritin and hemoglobin, reduced the risk of blood transfusion, and decreased the duration of stay in the hospital. Preoperative intravenous administration of ferric carboxymaltose to cardio-surgical patients can improve clinical outcomes and the cost effectiveness of cardiac surgery.

Critical Preoperative Hemoglobin Value to Predict Anemia-Related Complications After Cardiac Surgery

OBJECTIVES

Preoperative anemia is frequent in patients undergoing cardiac surgery and is associated with increased postoperative complications. The purpose of this observational study was to estimate the critical preoperative hemoglobin threshold associated with the occurrence of complications after cardiac surgery.

DESIGN

A retrospective observational cohort study.

SETTING

A tertiary-care medical center from January 2019 to April 2020.

PARTICIPANTS

A total of 1,004 patients undergoing elective cardiac surgery were included.

INTERVENTIONS

None (observational study).

MEASUREMENTS AND MAIN RESULTS

The primary study endpoint was to define the hemoglobin threshold that predicted the occurrence of postoperative major complications after elective cardiac surgery. Postoperative complications were a composite criterion, including transient ischemic attack or stroke, myocardial infarction, acute kidney injury, respiratory failure, mediastinitis, or mesenteric ischemia. A discrimination threshold was determined by using receiver operating characteristic curves. The discrimination threshold for hemoglobin concentration with the best sensitivity/specificity ratio for the occurrence of postoperative complications was 13 g/dL for male patients and 11.8 g/dL for female patients. The incidence of postoperative complications was 17.2% in the total population. Independent risks were preoperative hemoglobin concentration, red blood cell transfusion, European System for Cardiac Operative Risk Evaluation II, and the type of surgery.

CONCLUSIONS

The critical preoperative hemoglobin thresholds associated with the occurrence of postoperative complications with the best sensitivity/specificity ratio were 13 g/dL for men and 11.8 g/dL for women, which were very similar to the World Health Organization criteria defining anemia.

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.

Combination of hepcidin with neutrophil gelatinase-associated lipocalin for prediction of the development of sepsis-induced acute kidney injury

BACKGROUND AND AIMS

The early prediction of the development of acute kidney injury (AKI) in critically ill patients with sepsis would facilitate early effective intervention. Recently, interest has focused on the biomarkers for AKI-linked iron metabolism. This study aimed to assess the early predictive values of hepcidin, neutrophil gelatinase-associated lipocalin (NGAL), and their combination for secondary AKI in patients with sepsis.

MATERIALS AND METHODS

A prospective cohort study was performed in septic patients. Serum and urine hepcidin, and urine NGAL were analyzed at admission. The primary outcome measure was occurrence of sepsis-induced AKI based on 2011 Kidney Disease: Improving Global Outcomes (KDIGO) criteria during the first week of ICU stay.

RESULTS

Of the 90 patients analyzed finally in the study, 44 (48.9%) patients developed AKI. Patients with AKI occurrence were more likely than those without AKI to have higher serum hepcidin and urine NGAL levels at admission (P < 0.01). Higher concentrations of these biomarkers were each independent predictor of the development of AKI in critically septic patients within the first week of their ICU stay. Serum hepcidin and urine NGAL (AUROC 0.787, 95% CI 0.688 to 0.8660 and AUROC 0.729, 95% CI 0.625 to 0.818, respectively) were comparable predictive indicators of AKI occurrence (P = 0.43 for DeLong's test). Combining both biomarkers increased the AUROC to 0.828(95% CI 0.733 to 0.899), and this performance was statistically significantly better than urine NGAL alone (P = 0.03 for DeLong's test).

CONCLUSION

Serum hepcidin measured at admission predicts the development of AKI similarly to urine NGAL. However, serum hepcidin adds significant accuracy to this prediction in combination with urine NGAL alone and has a good predictive value in patients with sepsis. Larger studies are needed to validate and explain these findings.

Preoperative platelet count, preoperative hemoglobin concentration and deep hypothermic circulatory arrest duration are risk factors for acute kidney injury after pulmonary endarterectomy: a retrospective cohort study

Background

Acute kidney injury (AKI) is a major postoperative morbidity of patients undergoing cardiac surgery and has a negative effect on prognosis. The kidney outcomes after pulmonary endarterectomy (PEA) have not yet been reported; However, several perioperative characteristics of PEA may induce postoperative AKI. The objective of our study was to identify the incidence and risk factors for postoperative AKI and its association with short-term outcomes.

Methods

This was a single-center, retrospective, observational, cohort study. Assessments of AKI diagnosis was executed based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

Results

A total of 123 consecutive patients who underwent PEA between 2014 and 2018 were included.

The incidence of postoperative AKI was 45% in the study population. Stage 3 AKI was associated with worse short-term outcomes and 90-day mortality (p < 0.001, p = 0.002, respectively). The independent predictors of postoperative AKI were the preoperative platelet count (OR 0.992; 95%CI 0.984–0.999; P = 0.022), preoperative hemoglobin concentration (OR 0.969; 95%CI 0.946–0.993; P = 0.01) and deep hypothermic circulatory arrest (DHCA) time (OR 1.197; 95%CI 1.052–1.362; P = 0.006) in the multivariate analysis.

Conclusion

The incidence of postoperative AKI was relatively high after PEA compared with other types of cardiothoracic surgeries. The preoperative platelet count, preoperative hemoglobin concentration and DHCA duration were modifiable predictors of AKI, and patients may benefit from some low-risk, low-cost perioperative measures.

Simple Postoperative AKI Risk (SPARK) Classification before Noncardiac Surgery: A Prediction Index Development Study with External Validation

BACKGROUND

Researchers have suggested models to predict the risk of postoperative AKI (PO-AKI), but an externally validated risk index that can be practically implemented before patients undergo noncardiac surgery is needed.

METHODS

We performed a retrospective observational study of patients without preexisting renal failure who underwent a noncardiac operation (≥1 hour) at two tertiary hospitals in Korea. We fitted a proportional odds model for an ordinal outcome consisting of three categories: critical AKI (defined as Kidney Disease Improving Global Outcomes AKI stage ≥2, post-AKI death, or dialysis within 90 days after surgery), low-stage AKI (defined as PO-AKI events not fulfilling the definition of critical AKI), and no PO-AKI.

RESULTS

The study included 51,041 patients in a discovery cohort and 39,764 patients in a validation cohort. The Simple Postoperative AKI Risk (SPARK) index included a summation of the integer scores of the following variables: age, sex, expected surgery duration, emergency operation, diabetes mellitus, use of renin-angiotensin-aldosterone inhibitors, baseline eGFR, dipstick albuminuria hypoalbuminemia, anemia, and hyponatremia. The model calibration plot showed tolerable distribution of observed and predicted probabilities in both cohorts. The discrimination power of the SPARK index was acceptable in both the discovery (c-statistic 0.80) and validation (c-statistic 0.72) cohorts. When four SPARK classes were defined on the basis of the sum of the risk scores, the SPARK index and classes fairly reflected the risks of PO-AKI and critical AKI.

CONCLUSIONS

Clinicians may consider implementing the SPARK index and classifications to stratify patients' PO-AKI risks before performing noncardiac surgery.

Role of anesthesiologists in managing perioperative anemia

PURPOSE OF REVIEW

Anemia can contribute negatively to a patient's morbidity and mortality. Which treatment options do exist and what role do anesthesiologists play in management of perioperative anemia treatment? This review gives an overview about recent findings.

RECENT FINDINGS

Patient Blood Management and standards for the management and treatment of anemia have been established worldwide. Various logistic settings and approaches are possible. With a special focus on cardiovascular anesthesia, intravenous iron is a therapeutic option in the preoperative setting. Autologous blood salvage is a standard procedure during surgery. Restrictive transfusion triggers in adult cardiac surgery have been shown to be beneficial in the majority of studies. Elderly patients and defined comorbidities might require higher transfusion triggers. Both, intravenous and oral iron increase hemoglobin values when given prior to surgery. Oral iron is effective when given several weeks prior to elective surgery. Erythropoietin is a treatment decision individualized to each patient.

SUMMARY

Within the previous 18 months, important publications have demonstrated the established role of anesthesiologists in managing perioperative anemia. A substantial pillar for anemia treatment is the implementation of Patient Blood Management worldwide.