Topic Discussion: CABG( off pump vs on pump) and AKI

CABG induced AKI is fairly common.  Traditionally CABG is performed with bypass machine. Last decade has noted a surge in doing CABG via an off pump method. So you can get a CABG either off PUMP vs on PUMP.  If the pump is the problem and being on the bypass machine is what leads to the AKI, off PUMP CABG should have less AKI?

What is the data?

In 2010, a meta-analysis published in CJASN showed that off-pump CABG may be associated with a lower incidence of postoperative AKI but may not affect dialysis requirement, a serious complication of cardiac surgery. However, the different definitions of AKI used in individual trials and methodological concerns preclude definitive conclusions.

Then in 2014, Garg’s group from Canada did a large study looking at this question in the CORONARY study group in JAMA. They found that the use of off-pump compared with on-pump CABG surgery reduced the risk of postoperative acute kidney injury, without evidence of better preserved kidney function with off-pump CABG surgery at 1 year.

Another meta-analysis in 2015 from the Mayo clinic group showed a beneficial effect of off‐pump CABG on the incidence of AKI. However, this meta‐analysis does not show benefits of the need of dialysis or survival among patients undergoing off‐pump CABG.

In 2017, an Asian study published in Medicine found that among the 3 surgical methods( off pump, on pump with arrest heart, on pump with beating heart), off pump surgery resulted in lower AKI incidence. The short term outcome, including kidney function, of on pump beating heart surgery is similar to that of the off pump group.

The reasons that are proposed for higher AKI in on-pump CABG patients include renal hypoperfusion, hypotension, inflammation and oxidant stress. Compared to on-pump surgery, off pump surgery has potential benefits of reduced AKI risk and reduced cerebral dysfunction and reduced ICU stay and reduced mortality.

However, KDIGO guideline suggests that “off pump CABG not be selected for the purpose of reducing perioperative AKI or need for dialysis.”