Baseline data included clinical characteristics, symptom status, past medical history, markers of renal function including serum creatinine (SCrea) and estimated glomerular filtration rate. Postoperative levels of SCrea were obtained from medical records and estimated glomerular filtration rate calculated accordingly [8]. Indication for surgery was based on coronary angiography. The use of redo-OPCAB was based on surgeons using predominantly OPCAB or CABG with none undertaking a mixed practice. The OPCAB technique used was as previously reported [9, 10] using pressure stabilizer and intracoronary shunts. Anaesthesia and perfusion techniques were also as previously reported [11–14].