Acute kidney injury following cardiac surgery: impact of early versus late haemofiltration on morbidity and mortality

Abstract

Various forms of renal replacement therapies (RRT) are available to treat acute kidney injury (AKI) after cardiac surgery. The objective of this review is to assess the incidence of postoperative AKI that necessitates the application of haemofiltration in adult patients undergoing cardiac operations with cardiopulmonary bypass (CPB), to determine the factors that influence the outcome in these patients. In addition, the review aims to assess the outcomes of postoperative early haemofiltration as compared to late intensive haemofiltration. Different forms of RRT such as intermittent haemodialysis, continuous haemofiltration, or hybrid forms which combine advantages of both are now available for application in cardiac surgery patients, and will be discussed in this article. The underlying disease, its severity and stage, the aetiology of AKI, clinical and haemodynamic status of the patient, the resources available, and different costs of therapy may all influence the choice of the RRT strategy. AKI, with its risk of uraemic complications, represents an independent risk factor for adverse outcomes in critically ill patients after cardiac surgery. Whether early initiation of RRT is associated with improved survival is unknown, and also clear guidelines on RRT durations are still lacking. In particular, it remains unclear whether haemodynamically unstable patients who develop septic shock pre- and postoperatively can benefit from early RRT initiation. In addition, it is not known whether in AKI patients undergoing cardiac surgery RRT modalities can eliminate significant amounts of clinically relevant inflammatory mediators. This review gives an update of information available in the literature on possible mechanisms underlying AKI and the recent developments in continuous renal replacement treatment modalities.

The impact of continuous haemofiltration with high-volume fluid exchange during cardiopulmonary bypass surgery on the recovery of patients with impaired renal function: a pilot randomised trial

“…23 Newer developments in surgical techniques, such as minimally invasive surgery which avoids the manipulation of the ascending aorta, can also reduce kidney complications. 23 Although there is evidence from a variety of sources [24][25][26] that early filtration soon after on-pump surgery is beneficial for patients who have pre-operative renal impairment, there is a deficit of previous work on the clinical impact of intraoperative haemofiltration (haemofiltration applied during on-pump surgery). The Society of Thoracic Surgeons and the Society of Cardiovascular Anaesthesiologists' blood conservation practice guidelines 27 also recommend that the existing evidence, designated IIb(a) (p. 948), is insufficient to reach a consensus as to whether or not intraoperative haemofiltration is significantly beneficial.…”

Serum creatinine role in predicting outcome after cardiac surgery beyond acute kidney injury

“…The best starting time for postoperative RRT is also controversial. Most studies have found lower mortality with the earlier initiation of RRT [163,186,187] . In addition, recent guidelines suggest that using continuous RRT is superior to standard intermittent RRT in hemodynamically unstable patients [148] .…”

The Risk-Adjusted Impact of Intraoperative Hemofiltration on Real-World Outcomes of Patients Undergoing Cardiac Surgery

“…In contrast, the delayed use of postoperative hemo iltration on patients with known preoperative kidney impairment does not signi icantly impact occurrence of AKI and the impact of AKI on survival. It is with this reasoning and evidence from other studies [46][47][48] that we hypothesize that for patients with preoperative kidney disease routine application of intraoperative haemo iltration or early CVVH rather than the traditional delayed CVVH (which is commonly started 1-3 days after CABG in response to mostly oliguria symptoms and electrolytes imbalance) may improve outcomes of these vulnerable patients. The recent introduction of hemodial iltration techniques incorporating citrate-based regional anticoagulation systems soon after CPB may be a game changer for patients with preoperative kidney disease in routine clinical practice [49].…”