Formica 2013 (A).

Study characteristics
Methods	Prospective, parallel‐group, randomised clinical trial Run‐in period: between June and December 2011 Number of study centres and locations: single centre; Cardiac Surgery Clinic, Department of Surgical Science and Interdisciplinary Medicine, University of Milano‐Bicocca, San Gerardo Hospital, Monza, Italy
Participants	Sixty‐one participants undergoing isolated CABG were prospectively randomised to MECC (n = 19), SECC (n = 20), or OPCABG (n = 22). Mean age: 69.35 years Sex (female/male ratio): 21.11% Low‐risk patients Inclusion criteria: first and isolated CABG operation, at least two‐vessel disease, EF ≥ 40%, age between 18 years and 85 years, serum Cr levels < 1.8 mg/100 mL, and absence of inflammatory syndromes and haematological disorders Exclusion criteria: calcified and intramyocardial coronary arteries, recent or current steroid treatments, emergency or urgency operation, recent MI (< 10 days), unstable angina with IV medications, and preoperative IABP
Interventions	Intervention group: MECC. The MECC system (Maquet‐Jostra AG, Hirrlingen, Germany) was a closed miniaturised circuit with no blood–air contact and no open venous reservoir. The system components included a centrifugal Rotaflow pump, a polimethylpentene membrane Quadrox D oxygenator, a heat exchanger, a venous bubble trap VBT160 located between the venous line and the centrifugal pump, an arterial filter, and a 1000‐mL closed bag used to prime and substitute volume during CPB. Control group: standard ECC system. The standard extracorporeal system consisted of a polyvinylchloride heparin‐coated circuit (Maquet‐Jostra, Hirrlingen, Germany), a hollow‐fiber polypropylene oxygenator (Quadrox Maquet‐Jostra, Hirrlingen, Germany), an open reservoir, a roller pump (Stockert, Munchen, Germany), a system of blood suction from the surgical field, a heat exchanger, and an arterial filter (Maquet‐Jostra, Hirrlingen, Germany).
Outcomes	Primary outcomes: perioperative mortality and morbidity (AF, new MI) Secondary outcomes: blood lactate; haemodilution; markers for inflammation and endothelial activation such as TNF‐α, IL‐6, monocyte chemotactic protein‐1, and E‐selectin; clinical outcomes; TnT; and CK‐MB Timing: during and after surgery
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Preoperative characteristics did not differ amongst the three groups; no randomisation method description is given.
Allocation concealment (selection bias)	Unclear risk	All the operations were performed by the same senior surgeon; no allocation information is given.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not specified
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not specified
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Two participants in the OPCABG group were withdrawn from the trial because of intraoperative conversion of OPCABG to standard CPB after haemodynamic instability; no ITT analysis.
Selective reporting (reporting bias)	Unclear risk	Inflammatory outcomes were not reported properly: TNF‐α and E‐selectin without SD in the figures and D‐dimer data were not shown.
Other bias	Low risk	This work was funded by the University fund for scientific research (Fondo di Ateneo per la Ricerca), University of Milano‐Bicocca.