Data collection and clinical management
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].
Computed tomography angiography was used according to surgeon preference to ascertain the anatomical relation of the heart and grafts with the re-entry route. Left ventricular ejection fraction was derived from baseline echocardiogram or left ventriculogram. Our definition of reduced left ventricular ejection fraction was <50%. Intraoperative and postoperative data collection and clinical management were as previously reported [8]. Patients developing non-cardiac single organ renal, respiratory and/or neurological dysfunction/failure were treated till complete recovery and referred to a specialist centre for further management beyond the 30-days cut-off, if necessary.