Application of CLCVP Technique in Early Intervention of CSA-AKI

Acute kidney injury (AKI) is a common and serious complication after cardiac surgery, which is associated with worsen prognosis including longer hospitalization, elevated mortality and morbidity and greater healthcare costs.The pathophysiological mechanisms underlying the development of AKI after cardiac surgery are complex. Venous congestion during cardiac surgery rather than hypotension is independently associated with the postoperative adverse kidney events, for both AKI within 7 days postoperative and longer-term acute kidney disease (AKD) that develops between 8- and 90-day postoperative window.Central venous pressure (CVP) is used as an indicator to quantify the degree of venous congestion, and high CVP may reflect severe venous congestion, contributing to decreased organ perfusion pressure and negatively affect renal microcirculation.

Controlled low central venous pressure (CLCVP) technique is a common and safe technique in clinical surgery.CLCVP technology has been widely used in hepatectomy, but there are few studies on its application in cardiac surgery settings. Most scholars believe that it has no adverse effects on the kidneys, while some studies suggest that it has a certain protective effect on the kidneys, but the mechanism is unclear.Actively targeting lower CVP levels using fluid restriction, reverse Trendelenburg position, vasodilators and other methods by anesthetics, can significantly reduce major intraoperative bleeding events.CLCVP technique could potentially play a role in renal protection during cardiac surgery by easing venous congestion through reduced CVP levels.

We therefore carried out a controlled randomized clinical trial to study the effect of CLCVP technique on postoperative acute kidney complications after on-pump cardiac surgery. Specifically, we tested the hypothesis that CLCVP management reduces the incidence of postoperative AKI through lower intraoperative CVP levels.

Inclusion criteria

• Patients aged 18 years and older, who underwent cardiac surgery (coronary artery bypass grafting (CABG), heart valve surgery, heart transplant or surgical excision of intracardiac myxoma) were eligible for analyses.

Exclusion criteria

• pre-existing renal insufficiency defined by presence of abnormal preoperative serum creatinine ≥ 133 μmol/L and/or preoperative diagnosis of renal insufficiency within 6 months' preoperative period.
• patients with preoperative dialysis dependence within 60 days before surgery, off-pump heart surgery, prior kidney transplantation, pregnancy, as well as those under drug therapy with nitroglycerin were excluded.