Original articleAssociation Between Postoperative Acute Kidney Injury and Duration of Cardiopulmonary Bypass: A Meta-Analysis
Section snippets
Defining Acute Kidney Injury
The primary outcome was the development of new-onset AKI-CPB as defined by the Acute Kidney Injury Network (AKIN) criteria.5 Before the use of the AKIN classification, there had been up to 37 different definitions of renal failure in the medical literature, which made these studies very heterogenous and difficult to compare. These definitions varied from a 25% increase over baseline creatinine to the need for dialysis.6 The need for a consensus definition that also could be used to validate
CPB Time as Risk Factor for AKI
The CPB times for subjects with AKI-CPB and controls in all 9 studies are reported in minutes (mean ± standard deviation) (Table 2). The overall and absolute mean differences of duration of CPB and 95% CIs for each study are reported in Fig 2. In all 9 studies, the patient cohort with AKI reported longer CPB times compared with the cohort that did not develop AKI-CPB (control).
The absolute mean differences between the cohorts (AKI-CPB and control) for individual studies ranged from 3 minutes
Discussion
The spectrum of CPB-induced pathophysiologic changes includes the systemic inflammatory response, changes in renal vasomotor tone, destruction of red cells, pigment nephropathy, loss of pulsatile flow, activation of complement and coagulation pathways, and generation of microemboli (fibrin, platelet aggregates, cellular debris, fat, and air).
Other established patient and surgical risk factors include advanced age, preoperative renal insufficiency, ejection fraction <40%, excessive hemodilution
Conclusions
Longer duration of CPB is associated with an increased risk of developing postoperative AKI.
Acknowledgments
The authors thank Drs Provonchère, Landoni, and Conlon for their willingness to discuss the project and provide specific anonymous data (Drs Landoni and Provonchère) from their previously published studies.
References (24)
- et al.
Independent association between acute renal failure and mortality following cardiac surgery
Am J Med
(1998) - et al.
Renal dysfunction and serious infections after open-heart surgery
Kidney Int
(2003) - et al.
A comparison of the RIFLE and Acute Kidney Injury Network classifications for cardiac surgery associated acute kidney injury: A prospective cohort study
J Thorac Cardiovasc Surg
(2009) - et al.
The incidence and risk of acute renal failure after cardiac surgery
J Cardiothorac Vasc Anesth
(2004) - et al.
Predictors of ARF after cardiac surgical procedures
Am J Kidney Dis
(2003) - et al.
Does the combination of aprotinin and angiotensin-converting enzyme inhibitor cause renal failure after cardiac surgery?
Ann Thorac Surg
(2005) - et al.
Cardiopulmonary bypass duration is an independent predictor of morbidity and mortality after cardiac surgery
J Cardiothorac Vasc Anesth
(2008) - et al.
Coronary artery bypass grafting: The Society of Thoracic Surgeons national database experience
Ann Thorac Surg
(1994) - et al.
Cardiopulmonary bypass-associated acute kidney injury
Anesthesiology
(2011) - et al.
Minimal changes of serum creatinine predict prognosis in patients after cardiothoracic surgery: A prospective cohort study
J Am Soc Nephrol
(2004)