Coronary Bypass Grafting for Patients Dependent on Dialysis: Modified Ultrafiltration for Perioperative Management

Coronary Artery Bypass Grafting in Dialysis-Dependent Patients - Key Peri-Operative Considerations

Cardiovascular disease represents the leading cause of mortality in dialysis-dependent (DD) patients, with the great majority of these patients afflicted by severe coronary artery disease. As rates of end-stage renal disease increase worldwide, DD patients represent a growing proportion of the coronary artery bypass grafting (CABG) cohort. Yet, these patients are complex, with crucial changes in their haemodynamic and physiologic profiles that complicate revascularisation surgery. First, this comprehensive literature review explores the outcomes and prognostic factors for DD patients undergoing CABG. We then summarise the intricacies relating to important peri-operative decisions such as use of cardio-pulmonary bypass and choice of conduit.

Clinical outcome of intraoperative hemodialysis using a hemoconcentrator during cardiopulmonary bypass for dialysis-dependent patients

OBJECTIVES

The basic materials and structure of a hemoconcentrator incorporated into cardiopulmonary bypass (CPB) circuits are similar to those of hemodialyzers. Gravity drainage hemodiafiltration (GHDF) is an easy-to-use intraoperative renal replacement therapy (RRT) that utilizes a hemoconcentrator. This study aimed to verify whether GHDF can correct electrolyte imbalance and remove uremic toxins in dialysis-dependent patients and to evaluate the clinical outcomes of GHDF by comparing it with a conventional method of dilutional ultrafiltration (DUF).

METHODS

This study retrospectively compared perioperative clinical values of 41 dialysis-dependent patients (21 patients with GHDF and 20 patients with DUF) who underwent open-heart surgery. Changes in serum parameters before and after passing through the hemoconcentrator were also compared.

RESULTS

Compared to DUF, GHDF significantly lowered potassium, blood urea nitrogen, and creatinine levels at the outflow of the hemoconcentrator. Less catecholamine was needed to wean CPB in GHDF than in DUF. The P/F ratio (arterial blood oxygen pressure/inhaled oxygen concentration) at the end of surgery was significantly higher in GHDF than in DUF (450.8 ± 149.7 vs. 279.3 ± 153.5; p < 0.001). Postoperative intubation time was shorter in GHDF than in DUF (8.3 ± 5.9 vs. 18.7 ± 16.1 h; p = 0.006). The major morbidity and mortality rates were comparable in both groups.

CONCLUSIONS

GHDF removed both potassium and uremic toxins more efficiently than DUF in dialysis-dependent patients. Less catecholamine was needed to wean CPB using GHDF. It improved the immediate postoperative respiratory function and enabled earlier extubation. GHDF is a novel and effective option for intraoperative RRT in dialysis-dependent patients undergoing open-heart surgery.

Safety of perioperative hemodialysis and continuous hemodiafiltration for dialysis patients with cardiac surgery

OBJECTIVE

We have routinely used postoperative continuous hemodiafiltration (CHDF) combined with intraoperative hemodialysis (IHD) for dialysis patients undergoing open-heart surgery. This perioperative management could avoid any limitation of potassium concentration in the cardioplegic solution, strict restriction of fluid administration, or blood transfusion.

METHODS

To evaluate the safety of this strategy, 22 dialysis patients who underwent open-heart surgery (Dialysis Group) were retrospectively compared with 30 patients with normal renal function selected from the same time period with rigorously matched clinical characteristics such as age, gender, and operative procedures (Matched Group).

RESULTS

No significant difference was found in the operative variables such as the operative procedures, cardiopulmonary bypass time, and aortic cross-clamp time in both groups. There were two deaths (9.1%) in the Dialysis Group compared with Matched Group (0%). In the Dialysis Group, the levels of serum potassium and creatinine were well controlled in the perioperative period with a mean duration of IHD and CHDF of 243.7 +/- 60.6 min and 2.7 +/- 1.1 days, respectively. In particular, no significant difference between intraoperative and postoperative levels of serum potassium was observed in the Dialysis Group (P = 0.09), whereas there was a significant increase in the Matched Group (P = 0.004). Mean volume administered for the first 24 h after surgery was not different from the Matched Group. There were no vascular access-related complications in the Dialysis Group.

CONCLUSIONS

Postoperative CHDF combined with IHD can provide a similar management protocol for dialysis patients compared to patients with normal renal function.