Research Article

Preoperative White Blood Cell Count and Risk of 30-Day Readmission after Cardiac Surgery

Table 4

Characteristics of patients and white blood cell count categories.

CharacteristicWhite blood cell count (in 1,000s)
<6.06.0–7.98.0–9.910.0–12.0>12.0 value

Number of patients (2,176)433845541224133
Demographics
 Age <0.001
 Female30.329.526.631.727.80.594
 BMI <0.001
Comorbidities
 Type 2 diabetes mellitus26.331.636.832.634.60.014
 Vascular disease25.627.927.929.928.60.817
 COPD12.214.719.420.118.10.009
 History of dialysis2.12.42.62.77.50.013
 Smoking9.717.928.835.730.1<0.001
Cardiac history
 Recent MI7.615.517.628.133.1<0.001
 CHF18.718.721.422.330.80.017
 Prior CABG5.13.93.11.84.50.256
 Prior valve2.51.30.91.33.00.173
 Prior PCI15.918.619.217.018.80.699
 NYHA Class IV12.012.216.624.629.3<0.001
Cardiac anatomy and function
 Left main disease ≥50%22.927.927.931.337.60.012
 Single-vessel disease41.634.733.028.126.80.013
 Two-vessel disease27.528.228.832.928.5
 Three-vessel disease30.937.238.239.144.7
 Ejection fraction
  <40%9.49.312.015.022.8<0.001
  40%–59%11.110.914.118.29.5
  50%–59%25.924.224.121.526.0
  ≥60%53.555.549.845.341.7
Procedural characteristics
 Priority
  Emergent1.62.86.110.323.3<0.001
  Urgent46.047.951.261.260.9
  Elective52.449.242.728.615.8
 Procedure
  CABG50.659.162.567.466.2<0.001
  Valve31.423.721.315.216.5
  CABG/valve18.017.316.317.417.3
 On-pump surgery92.492.088.789.790.20.213
 Nadir hematocrit <20 on bypass11.815.013.712.115.80.465
 Cardiopulmonary bypass time (min) 0.656
 Time to initial extubation (min) <0.001
 Intraoperative myocardial infarction1.22.52.43.14.50.203
 Return to bypass5.14.73.03.15.30.343
Management
 RBC transfusion36.332.930.731.743.60.041
 Use of 2 or more inotropes within 48 hours2.13.62.54.54.60.278
Adverse outcomes
 Low-cardiac output failure7.48.86.78.514.30.063
 Stroke1.20.81.51.80.80.687
 Mediastinitis0.20.70.60.91.50.552
 Acute kidney injury29.333.631.437.538.40.128
 Reintubation3.02.84.84.55.30.239
 Return to operating room for bleeding6.03.11.92.24.50.005
 New atrial fibrillation32.134.831.832.636.80.650
 Leg wound infection0.70.80.71.30.00.731
 Pneumonia1.61.41.13.11.50.354

COPD: chronic obstructive pulmonary disease; MI: myocardial infarction; CHF: congestive heart failure; CABG: coronary artery bypass graft surgery; PCI: percutaneous coronary intervention; WBC: white blood cell; eGFR: estimated glomerular filtration rate; CABG: coronary artery bypass graft surgery; RBC: red blood cell; ICU: intensive care unit.