Study	Reason for exclusion
Bilgin 2002	Did not meet inclusion criteria. Blood transfusion, no filter on arterial line of cardiopulmonary bypass
Dell'Amore 2010	Not an arterial line filter. Residual blood
El‐Tahan 2009	Did not meet inclusion criteria. Ultrafiltration, no filter on arterial line of cardiopulmonary bypass
Gott 1998	Did not meet inclusion criteria. Not solely arterial line leukodepletion; also leukodepleted cardioplegia, salvaged and post‐operative blood products
Gu 1999a	Did not meet inclusion criteria. Filter on venous line of cardiopulmonary bypass
Hamada 2001	Did not meet inclusion criteria. Patients for coronary artery bypass graft
Johnson 1995	Did not meet inclusion criteria. Patients for coronary artery bypass graft
Karaiskos 2004	Not an RCT and did not meet exclusion criteria: mean ejection fraction; filter = 27%, control = 31%
Komai 1998	Did not meet inclusion criteria. Patients for ventricular septal defect
Lust 1996	Did not meet exclusion criteria. Patients for coronary artery bypass graft
Matheis 2001b	Did not meet inclusion criteria. Patients for coronary artery bypass graft
Onorati 2011	Did not meet inclusion criteria. Not solely arterial line leukodepletion; also leukodepleted cardioplegia
Pala 1995	Did not meet inclusion criteria. Leukodepletion on cardioplegia circuit only
Scholz 2002	Did not meet inclusion criteria. Patients for coronary artery bypass graft
Smit 1999	Did not meet inclusion criteria. Filter on venous line of cardiopulmonary bypass
Soo 2008	Did not meet inclusion criteria. In vitro study (see Soo 2010)
Soo 2009	Did not meet inclusion criteria. In vitro study (see Soo 2010)
van de Watering 1996	Did not meet inclusion criteria. Blood transfusion, no filter on arterial line of cardiopulmonary bypass
Zhang 2005	Did not meet inclusion criteria. No leukocyte depletion filter