{
  "abstract": "There is a paucity of biomarkers for risk stratification following cardiac surgery. The red blood cell distribution width (RDW) – a standard component of routine CBC – quantifies the variation of RBC volumes during their lifespan. Elevated RDW is independently associated with morbidity and mortality across various metabolic and infectious conditions, and is a surrogate measure of fragility. Whether RDW can aid in risk stratification following cardiac surgery is unknown, and was the subject of this investigation.We evaluated the association of RDW with outcomes in patients enrolled in the global TRICS III randomized trial which compared restrictive to liberal blood transfusion in adult patients undergoing cardiac surgery. The primary composite outcome included death from any cause, myocardial infarction, stroke, or new-onset severe renal failure by hospital discharge at 28-days post-operatively. Secondary outcomes included all-cause death at 28 days and 6-months respectively.This analysis included 3658 patients for whom RDW was available (mean age 72±10; 63% male; EuroScore II 7.9±2.0; 26% CABG; 19% CABG+valve; 28% valve; 27% other). Elevated RDW was significantly and independently associated with incident primary adverse cardiorenal events at 28-days (highest RDW quartile vs. lowest RDW quartile, HR 1.96 (1.48–2.60); p<0.0001). A similar association was observed for key secondary outcomes of prolonged low-output state, acute kidney injury and new renal failure at 28 days post-operatively. Strikingly, following multivariate adjustment, elevated RDW was strongly associated with all-cause death at 28-days and 6-months following surgery (highest vs. lowest RDW quartile at 28-days: HR 2.12 (1.24–3.61); p<0.01 and 6 months: HR 2.42 (1.60–3.05); p<0.0001) (table 1), (figure 1).In this large trial of patients undergoing cardiac surgery, elevated RDW was associated with an increase in cardiorenal events, and short- and long-term mortality risk after multivariate adjustment. RDW may be a simple, inexpensive and highly predictive biomarker for adverse perioperative outcomes in cardiac surgery.Abstract 23 Table 1Adjusted odds ratios across RDW quartiles for primary and secondary outcomes Outcome ≤13 % 13.0- 13.7 % 13.8- 14.8 % ≥14.9 % P-Trend Per 1% Increase Primary composite outcome Reference 1.26 (0.92, 1.71) 1.28 (0.95, 1.73) 1.37 (1.01, 1.87) 0.21 1.04 (1.01,1.06) P-Value 0.14 0.10 0.04 <0.001 All-cause death Reference 0.98 (0.53, 1.81) 1.54 (0.90, 2.64) 2.12 (1.24, 3.61) 0.01 1.03 (1.00,1.06) P-Value 0.96 0.12 0.006 0.038 New-onset renal failure Reference 1.83 (0.97, 3.46) 1.79 (0.96, 3.32) 1.87 (1.01, 3.48) 0.20 1.04 (1.00,1.07) P-Value 0.06 0.06 0.04 0.026 Stroke Reference 1.94 (0.93, 4.01) 1.96 (0.96, 3.99) 1.00 (0.43, 2.33) 0.08 1.01 (0.95,1.07) P-Value 0.07 0.06 0.99 0.73 Myocardial infarction Reference 1.04 (0.70, 1.54) 0.80 (0.53, 1.19) 0.91 (0.60, 1.38) 0.60 1.03 (0.99,1.05) P-Value 0.85 0.27 0.65 0.074 Prolonged LOS Reference 1.23 (1.00, 1.50) 1.52 (1.26, 1.85) 1.92 (1.56, 2.36) <0.001 1.09 (1.06,1.11) P-Value 0.045 <0.001 <0.001 <0.001 Acute kidney injury Reference 1.11 (0.91, 1.36) 1.17 (0.96, 1.42) 1.23 (1.00, 1.52) 0.23 1.03 (1.01,1.05) P-Value 0.31 0.12 0.04 0.002 Infection Reference 1.38 (0.84, 2.25) 1.49 (0.93, 2.39) 1.80 (1.12, 2.90) 0.12 1.04 (1.01,1.06) P-Value 0.20 0.098 0.01 0.004 All-cause death at 6-months Reference 1.09 (0.68, 1.74) 1.35 (0.87, 2.08) 2.42 (1.60, 3.65) <0.001 1.03 (1.01,1.05) P-Value 0.73 0.18 <0.001 0.004 Data are presented as Hazard Ratio (95% Confidence Intervals). HR, hazard ratio; LOS, low-output state; RDW, red blood cell distribution width. Acute Kidney Injury (AKI) was defined by the Kidney Disease Improving Global Outcomes clinical practice guideline (KDIGO) as:(a) a 50% or greater increase in serum creatinine (from preoperative value) within 7 days; (b) a 26.5 μmol/L (0.3mg/dl) or greater increase from preoperative value within 48 hours; or (c) urine volume less than 0.5 ml/kg/h for 6 hours. Renal function was characterized as follows: Normal (CC >85ml/min); Moderate (CC > 50 and < 85ml/min); Severe (CC < 50ml.min) as per trial protocol. New-onset renal failure was defined as postoperative dialysis (excluding dialysis during CPB), which excludes patients who had received preoperative dialysis within four weeks prior to surgery. Renal dysfunction was defined by KDIGO criteria and only stage 3 were included as outcome measures.Abstract 23 Figure 1Relationship of RDW and survival after cardiac surgery cox proportional hazards regression analysis illustrating adjusted survival probabilities over 80 days, stratified by preoperative red blood cell distribution width quartiles (≤13%, 13.0–13.7%, 13.8–14.8%, ≥14.9%). The survival curves reveal a stepwise decline in survival probability with increasing red blood cell distribution width levels",
  "authors": [
    {
      "affiliations": [
        "Royal College of Surgeons in Ireland, Dublin, Ireland"
      ],
      "name": "R Verma"
    },
    {
      "affiliations": [
        "Cardiovascular and Thoracic Surgery, Cleveland Clinic, Cleveland, Ohio, USA"
      ],
      "name": "M Hibino"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, University of Toronto, Toronto, Ontario, Canada",
        "Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada"
      ],
      "name": "N Dhingra"
    },
    {
      "affiliations": [
        "Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada"
      ],
      "name": "S Patel"
    },
    {
      "affiliations": [
        "Epic Hospital, Ahmedabad, India"
      ],
      "name": "C Mehta"
    },
    {
      "affiliations": [
        "Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada",
        "Division of Hematology, Mount Sinai Hospital, Toronto, Ontario, Canada",
        "Division of Medical Oncology and Hematology, University Health Network, Toronto, Ontario, Canada",
        "Departments of Medicine, Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada",
        "Institute of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada"
      ],
      "name": "N Shehata"
    },
    {
      "affiliations": [
        "Division of Cardiac Surgery, University of Toronto, Toronto, Ontario, Canada",
        "Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada",
        "Division of Cardiovascular Surgery, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada",
        "Department of Surgery, University of Toronto, Toronto, Ontario, Canada"
      ],
      "name": "T Yau"
    },
    {
      "affiliations": [
        "Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada",
        "Department of Anesthesia, Li Ka Shing Knowledge Institute, St. Michael Hospital of Unity Health Toronto, Toronto, Ontario, Canada",
        "Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, Ontario, Canada",
        "Department of Physiology, University of Toronto, Toronto, Ontario, Canada",
        "Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada"
      ],
      "name": "CD Mazer"
    }
  ],
  "title": "23 Increased red blood cell distribution width is a marker of adverse cardiorenal outcomes following cardiac surgery",
  "uid": "8c80d43e-4a2b-55d5-b6ec-8739946047ce"
}