Pre-operative volume replacement versus usual care in diabetic patients having coronary artery bypass graft (CABG) surgery: a randomised controlled trial

Current primary outcome measures as of 15/05/2009:
Time until patients are classified as 'fit for discharge' since renal impairment is expected to impact on the risk of many post-operative complications. A patient must have normal temperature, pulse and respiration, normal oxygen saturation on air, normal bowel function and be physically mobile in order to be classified as fit for discharge.

Previous primary outcome measures:
Time until patients are classified as 'fit-for-discharge' since renal impairment is expected to impact on the risk of many post-operative complications. In order to be classified as fit for discharge, a patient must have a chest X-ray with no evidence of pleural effusion requiring drainage, lung collapse/consolidation or pneumothorax, no suspected infection, normal routine blood tests and temperature and be physically mobile.

Current secondary outcome measures as of 08/04/2013 (changes implemented as of 16/01/2013):
1. A participant’s judgement about his or her readiness for discharge when the above criteria are met (too soon, about right, could have been discharged earlier);
2. Estimated GFR (eGFR) from serum creatinine measured from blood samples collected preoperatively (baseline, pre-trial intervention), and at 0, 12, 24, 36, 48, 72, 96 and 120 hours after the operation and the % of participants with GFR<60 mL/min on 2 of the 8 post-operative times;
3. Microalbumin/creatinine ratio measured in urine samples collected preoperatively (baseline, pre-trial intervention) and at 0, 24, 48 and 120 hours to assess microvascular disease and renal glomerular injury.
4. Tubular injury as expressed by N-acetyl glucosaminidase (NAG) release measured in urine samples collected preoperatively (baseline, pre-trial intervention) and at 0, 24, 48 and 120 hours in a consecutive sub-sample of 50 patients.
5. Acute Kidney Injury (AKI, doubling of baseline serum creatinine at any time); serum creatinine will be measured from blood samples collected preoperatively (baseline, pre-trial intervention) and at 0, 24, 48, 72, 96, and 120 hours; the peak of postoperative serum creatinine level will be used in relation to the preoperative value to calculate the incidence of AKI;
6. In-hospital mortality and other standard measures of morbidity as used in previous RCTs, e.g. post-operative myocardial infarction (MI), stroke, arrhythmia, need for haemodynamic support, renal failure and wound infection (including 6-8 week telephone ASEPSIS assessment);
7. Use of health care resources and associated costs, e.g. duration of operation, intensive care unit (ICU)/high dependency unit (HDU) and ward stay, additional interventions to treat complications, readmissions;
8. Coronary Revascularisation Outcome Questionnaire (CROQ) preoperatively (preoperative version) and at 3 months.
9. The following outcomes will be measured in a consecutive sub-sample of 40 patients.
9.1. Preoperative blood glucose control, as measured by fasting blood glucose and haemoglobin A1c (HbA1c) prior to chest opening but after the intervention.
9.2. MicroRNA and other biochemical predictors of health outcome in serum and plasma taken preoperatively (baseline, pre-trial intervention) and at 0, 24 and 120 hours after the operation, and also in any leftover material/specimens collected during surgery (this may include, but is not limited to: portions of internal mammary arteries with surrounding tissues, pericardial fluid, pericardial fat/adipose tissue, pericardium, waste blood).
9.3. C-reactive protein as a marker of inflammation, measured preoperatively (baseline, pre-trial intervention) and at 0, 12, 24, 48, 72 and 120 hours after the operation.
9.4. Cardiac damage as measured with serial troponin T release measured pre-operatively (baseline, pre-trial intervention) and at 0, 12, 24, 48, 72 and 120 hours after the operation.

Previous secondary outcome measures as of 01/05/2012:
1. A participant's judgement about his or her readiness for discharge when the above criteria are met (too soon, about right, could have been discharged earlier)
2. Estimated GFR from serum creatinine measured from blood samples collected preoperatively, and at 0, 12, 24, 36, 48, 72, 96 and 120 hours after the operation) and the % of participants with GFR <60 mL/min on 2 of the 8 post-operative times
3. Microalbumin/creatinine ratio measured in urine samples collected preoperatively and at 0, 24, and 48 hours to assess microvascular disease and renal glomerular injury
4. Tubular injury as expressed by by N-acetyl glucosaminidase (NAG) release measured in urine samples collected preoperatively and at 0, 24, and 48 hours in a consecutive sub-sample of 80 patients.
5. Acute Kidney Injury (AKI, doubling of baseline serum creatinine at any time); serum creatinine will be measured from blood samples collected preoperatively and at 0, 24, 48, 72, 96, and 120 hours; the peak of postoperative serum creatinine level will be used in relation to the preoperative value to calculate the incidence of AKI
6. In-hospital mortality and other standard measures of morbidity as used in previous RCTs, e.g., post-operative MI, stroke, arrhythmia, need for haemodynamic support, renal failure and wound infection (including 4-6 week telephone ASEPSIS assessment)
7. Use of health care resources and associated costs, e.g., duration of operation, ICU/HDU and ward stay, additional interventions to treat complications, readmissions
8. Coronary Revascularisation Outcome Questionnaire (CROQ) preoperatively (preoperative version) and at 3 months

Previous secondary outcome measures as of 15/05/2009:
1. A participant's judgement about his or her readiness for discharge when the above criteria are met (too soon, about right, could have been discharged earlier)
2. Estimated GFR from serum creatinine measured from blood samples collected preoperatively, and at 0, 12, 24, 36, 48, 72, 96 and 120 hours after the operation) and the % of participants with GFR <60 mL/min on 2 of the 7 post-operative times
3. Microalbumin/creatinine ratio measured in urine samples collected preoperatively and at 0, 24, and 48 hours to assess microvascular disease and renal glomerular injury
4. Tubular injury as expressed by by N-acetyl glucosaminidase (NAG) release measured in urine samples collected preoperatively and at 0, 24, and 48 hours in a consecutive sub-sample of 80 patients.
5. Acute Kidney Injury (AKI, doubling of baseline serum creatinine at any time); serum creatinine will be measured from blood samples collected preoperatively and at 0, 24, 48, 72, 96, and 120 hours; the peak of postoperative serum creatinine level will be used in relation to the preoperative value to calculate the incidence of AKI
6. In-hospital mortality and other standard measures of morbidity as used in previous RCTs, e.g., post-operative MI, stroke, arrhythmia, need for haemodynamic support, renal failure and wound infection (including 4-6 week telephone ASEPSIS assessment)
7. Use of health care resources and associated costs, e.g., duration of operation, ICU/HDU and ward stay, additional interventions to treat complications, readmissions
8. Coronary Revascularisation Outcome Questionnaire (CROQ) preoperatively (preoperative version) and at 3 months

Previous secondary outcome measures:
1. A participant's judgment about his or her readiness for discharge when the above criteria are met (too soon, about right, could have been discharged earlier)
2. Estimated glomerular filtration rate (GFR) from serum creatinine measured from blood samples collected pre-operatively, and at 0, 4, 12, 24 and 48 hours after the operation) and the percentage of participants with GFR less than 60 mL/min on two of the five post-operative times
3. Renal glomerular and tubular injury as expressed by microalbumin/creatinine ratio and by N-acetyl glucosaminidase (NAG) release respectively and measured in urine samples collected pre-operatively and at 0, 24, and 48 hours in a consecutive sub-sample of 80 patients
4. Acute renal failure (ARF) (doubling of baseline serum creatinine at any time). Serum creatinine will be measured from blood samples collected pre-operatively and at 0, 24, 48, 72, 96, and 120 hours; the peak of post-operative serum creatinine level will be used in relation to the pre-operative value to calculate the incidence of ARF
5. In-hospital mortality and other standard measures of morbidity as used in previous randomised controlled trials, e.g., post-operative myocardial infarction (MI), stroke, arrhythmia, need for haemodynamic support, renal failure and wound infection (including 4 - 6 week telephone ASEPSIS assessment)
6. Use of health care resources and associated costs, e.g. duration of operation, intensive care unit (ICU)/high dependency unit (HDU) and ward stay, additional interventions to treat complications, readmissions
7. Coronary Revascularisation Outcome Questionnaire (CROQ) pre-operatively (pre-operative version) and at 3 months