Red blood cell distribution width as a novel prognostic marker after myocardial revascularization or cardiac valve surgery

Association of red blood cell distribution width and hemoglobin-to-RDW ratio with contrast-associated acute kidney injury in patients undergoing coronary angiography: A retrospective study

BACKGROUND

Inflammation contributes to poor prognosis in cardiovascular diseases. A novel biomarker for systemic inflammation that has garnered attention is the red blood cell distribution width (RDW). This study is designed to explore potential associations between RDW and hemoglobin-to-RDW ratio (HRR) with contrast-associated acute kidney injury (CA-AKI).

METHODS

This study retrospectively analyzed 4054 patients undergoing coronary angiography (CAG). Linear regression models were employed to assess the relationships between RDW or HRR and the elevation of serum creatinine (Scr). The associations between RDW or HRR and CA-AKI were explored using restricted cubic spline and log-binomial regression analyses taking into account specific cutoff values and quintiles. Exploratory analyses were also conducted to further investigate these associations.

RESULTS

Among enrolled patients, the average age was 66.9 years and 34.3% were female. Notably, patients who developed CA-AKI tended to have higher RDW and lower HRR. Multivariable linear regression models demonstrated that RDW exhibited a positive association with Scr elevation (β = 2.496, 95% confidence interval [CI] = 1.784-3.208), while HRR displayed a negative association (β = -3.559, 95% CI = -4.243 to -2.875). Multivariable log-binomial regression models confirmed that both high RDW (RDW ≥ 13.8%) and low HRR (HRR < 8.9) were significantly associated with a higher risk of CA-AKI (RDW [≥13.8% vs. <13.8%]: relative risk [RR] = 1.540, 95% CI = 1.345-1.762; HRR [<8.9 vs. ≥8.9]: RR = 1.822, 95% CI = 1.584-2.096). Exploratory analysis determined that such associations still existed regardless of age, gender, estimated glomerular filtration rate, or anemia.

CONCLUSIONS

Elevated preoperative RDW and decreased HRR were significantly associated with CA-AKI in patients undergoing CAG.

The Prognostic Significance of Red Cell Distribution Width in Cardiac Surgery: A Systematic Review and Meta-Analysis

RED CELL DISTRIBUTION WIDTH (RDW) is a routinely available biomarker of likely erythropoietic dysfunction, which may be associated with adverse outcomes after cardiac surgery. This systematic review and meta-analysis aimed to clarify the prognostic value of RDW in patients undergoing cardiac surgery. The authors searched MEDLINE, Embase, and the Cochrane Library from inception to May 10, 2022 for studies investigating the association between elevated RDW (as defined by the authors of included studies) and adverse outcomes after cardiac surgery. Herein, the authors extracted maximally adjusted hazard ratios (HRs) and odds ratios (ORs) with associated CIs, and pooled them using random-effects inverse- variance modeling. The authors explored interstudy heterogeneity using metaregression. The authors included 26 studies involving 48,092 patients who had undergone cardiac surgery. Elevated preoperative RDW was associated with long-term mortality (pooled HR 1.63, 95% CI 1.05-2.52), short-term mortality (pooled OR 2.16, 95% CI 1.21-3.87), acute kidney injury (AKI; pooled OR 1.30, 95% CI 1.19-1.41) and postoperative atrial fibrillation (POAF; pooled OR 1.44, 95% CI 1.05-1.96). Some studies suggested a significant association between preoperative RDW elevation and neurologic complications; however, their number was insufficient for meta-analysis. The postoperative RDW levels were less consistently reported and could not be meta-analyzed. In conclusion, the authors found that elevated preoperative RDW was associated with increased short- and long-term mortality, POAF, and AKI after cardiac surgery. Further research is needed to investigate its role in the risk stratification of patients undergoing cardiac surgery.

Preoperative red cell distribution width to lymphocyte ratio as biomarkers for prolonged intensive care unit stay among older patients undergoing cardiac surgery: a retrospective longitudinal study

Introduction: Our aim was to use the red cell distribution width-lymphocyte ratio (RLR) as a novel biomarker to predict prolonged intensive care unit (ICU) length of stay (LOS) among older patients undergoing cardiovascular surgery. Methods: This longitudinal study included older patients admitted to a tertiary cardiovascular surgery hospital between January 2017 and January 2022. Results: A total of 574 patients were studied, including 83 patients (14.5%) who had prolonged ICU LOS and 471 (85.5%) control subjects. After adjustment for the European System for Cardiac Operative Risk Evaluation 2, the RLR score showed a 10% increased risk of prolonged ICU LOS (odds ratio: 1.10; CI: 1.05-1.16; p = 0.01). Conclusion: Preoperative RLR can be used to predict the risk of long-term intensive care stay in older cardiac surgery patients.

Relationship Between High-Density Lipoprotein-Cholesterol and Red Cell Distribution Width in Patients With Coronary Artery Disease

Background

A high red cell distribution width (RDW), which indicates ongoing inflammation, and low levels of high-density lipoprotein-cholesterol (HDL-C) are associated with increased mortality and morbidity in patients with coronary artery disease (CAD). Recent studies have suggested that HDL-C possesses anti-inflammatory and antioxidant effects, which may explain its anti-atherogenic properties. This study aims to determine the relationship between HDL-C levels and RDW in patients with CAD.

Materials and methods

This cross-sectional study was performed on 120 patients with CAD from July 2020 to June 2021 in the Hematology Department of Chughtai Lab Lahore. Patients were graded according to the degree of coronary artery stenosis as follows: Grade 1,30%-50%; Grade 2, 51%-70%; and Grade 3,>70%. The HDL-C level was measured from venous blood samples by a fully automated Abbot Alinity analyzer. The RDW was measured by Sysmex XN-5000. The sample size was calculated using the Select Statistics calculator. The mean RDW and HDL-C of the patients were calculated, and correlation analyses were performed using the Pearson correlation coefficient.

Results

The HDL-C level was inversely related to the RDW. Of the 120 patients, 38, 44, and 38 had Grade 1, Grade 2, and Grade 3 stenosis, respectively. The mean HDL-C level and RDW were 30.58 ±3.77 mg/dL and 16.04% ±1.66%, respectively. The value of r was −0.8622 (strongly negative). Data were stratified based on the degree of stenosis. The values of r in Grades 1, 2, and 3 were −0.43 (moderately negative), −0.604 (moderately negative), and −0.27 (weakly negative), respectively.

Conclusion

The RDW can be used as an additional marker to determine the disease status in CAD patients.

Omega-3 index is directly associated with a healthy red blood cell distribution width

Low red blood cell (RBC) membrane content of EPA and DHA, i.e., the omega-3 index (O3I), and elevated RBC distribution width (RDW) are risk factors for all-cause mortality. O3I and RDW are related with membrane fluidity and deformability. Our objective was to determine if there is a relationship between O3I and RDW in healthy adults. Subjects without inflammation or anemia, and with values for O3I, RDW, high-sensitivity C-reactive protein (CRP), body mass index (BMI), age and sex were identified (n = 25,485) from a clinical laboratory dataset of  > 45,000 individuals. RDW was inversely associated with O3I in both sexes before and after (both p < 0.00001) adjusting models for sex, age, BMI and CRP. Stratification by sex revealed a sex-O3I interaction with the RDW-O3I slope (p < 0.00066) being especially steep in females with O3I ≤ 5.6%. In healthy adults of both sexes, the data suggested that an O3I of > 5.6% may help maintain normal RBC structural and functional integrity.