Introduction
Coronary artery bypass grafting (CABG) surgery for coronary artery
disease (CAD) remains the most common cardiac surgery performed in the
USA and Canada4. The increased age of patients along
with risk factors for CAD (i.e., hypertension (HTN), diabetes mellitus
(DM), obesity and chronic kidney disease (CKD) increase the
perioperative risk for acute kidney injury (AKI) and subsequent fluid
overloaded (FO) states. The incidence of post operative AKI after
cardiac surgery has been reviewed and reported as high as
40%.5 Understandably, the two most common chronic
risk factors for heart disease (i.e., HTN and DM) are also the leading
causes for chronic kidney disease in the USA6. Pre,
intra and post operative factors for AKI include but are not limited to
baseline preoperative heart failure states, baseline renal function,
intraoperative intravenous fluid over or under hydration, and or
decreased renal excretion7-9. Other perioperative risk
factors for AKI include dye contrast from cardiac angiography and the
systemic inflammatory response syndrome (SIRS) due to surgery. More
concerning, is the relatively high failure to rescue (FTR) rate reported
for post cardiac surgery AKI3. Although the STS
mortality risk score is the most common indicator used to differentiate
low, medium, and high-risk cardiac surgical patients, it fails to
predict and capture other well-known high mortality risk factors
including uncontrolled DM (i.e., HgbA1c level)10,
nutritional status (i.e., albumin level) and decompensated heart failure
(i.e., BNP levels). According to the most recent 2019 STS results, the
average in-hospital and 30-day mortality rates for CABG are 1.8% and
2.2%, respectively7. Excess fluid overload in the
perioperative phase of care has also been associated with increase
morbidity and mortality6. Modified Ultrafiltration
(MUF) techniques have been used for decades in the operating room to
remove fluid but the use of simplified UF in the post operative cardiac
surgery period has not been fully investigated. Enhanced Recovery after
Surgery (ERAS) recommends using goal directed therapy (GDT) to avoid
excess perioperative salt and water intravenous infusions and
maintenance of euvolemia11, 12. Simplified
ultrafiltration therapy with its low extracorporeal volume can be used
to accomplish this task safely by removing isotonic plasma water in the
post-operative period.
The current data evaluates a simplified UF technology for the removal of
isotonic plasma water in high-risk post operative cardiac surgery
patients. No randomized controlled trial data has yet been published on
this subject. Results presented in this paper show safety and
applicability of this technology in post cardiac surgery care.