Extracorporeal Blood Purification and Acute Kidney Injury in Cardiac Surgery - SIRAKI02

Oct 18, 2024
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Author/Summarized by Author:
Amit Saha, MD
Summary Reviewer:
Anthony A. Bavry, MD,MPH,FACC
Trial Sponsor:
Hospital Universitari de Bellvitge, Public Health Ministry of Spain, and Baxter International
Date Published:
10/09/2024
Original Posted Date:
10/18/2024
References

Contribution To Literature:

The SIRAKI02 trial showed that in patients undergoing nonemergent cardiac surgery, extracorporeal blood purification reduced the incidence of cardiac surgery-associated AKI at postoperative day 7.

Description:

The goal of the trial was to determine the efficacy of extracorporeal blood purification (EBP) in mitigating the risk of cardiac surgery-associated acute kidney injury (CSA-AKI).

Study Design

  • Randomized
  • Double-blind
  • Dual-center

Patients undergoing nonemergent cardiac surgery were randomized in a 1:1 fashion to receive EBP (n = 169) or usual care (n = 174) while on cardiopulmonary bypass (CPB). EBP was performed via slow ultrafiltration using the oXiris system, a nonselective acrylonitrile-sodium methallylsulfonate/polyethylenimine membrane that can adsorb circulating cytokines and endotoxin released during CBP. Volume removal via ultrafiltration could be performed in either arm if indicated, with a non-EBP membrane used in the control arm.

  • Total number of enrollees: 343
  • Duration of follow-up: 90 days
  • Mean patient age: 69 years
  • Percentage female: 35%

Inclusion criteria:

  • Age ≥18 years
  • Planned for nonemergent cardiac surgery
  • Estimated CPB time >90 minutes

Exclusion criteria:

  • Estimated glomerular filtration rate <30 mL/min/1.73 m2
  • Renal replacement therapy <3 months prior
  • Ongoing immunosuppressive therapy with steroids equivalent to >0.5 mg/kg/day prednisone or nonsteroidal agent
  • Underlying autoimmune disease with or without treatment

Other salient features/characteristics:

  • Hypertension: 73%
  • Diabetes: 30%
  • Chronic kidney disease stage (CKD) 1-3b: 18%
  • Renin-angiotensin-aldosterone system inhibitor use: 58%
  • Mean baseline creatinine, EBP vs. usual care: 1.02 vs. 1.04
  • Median EuroSCORE II, EBP vs. usual care: 2.62% vs. 2.22%

Principal Findings:

The primary outcome, incidence of CSA-AKI, defined as an increase in serum creatinine ≥0.3 mg/dL in 48 hours or by ≥1.5 times baseline or urine output <0.5 mL/kg/hour for ≥6 hours, for EBP vs. usual care, was: 28.4% vs. 39.7%, adjusted difference 10.4% (95% confidence interval [CI] 2.3%-18.5%), p = 0.01.

Secondary outcomes for EBP vs. usual care:

  • Peak serum creatinine at 7 days: 1.26 vs. 1.39 mg/dL, p = 0.11
  • Renal replacement therapy at 7 days: 1.8% vs. 3.5%, p = 0.50
  • Intensive care unit length of stay: 3 vs. 3 days, unadjusted difference 0 days (95% CI -1 to 1)
  • Hospital length of stay: 13 vs. 13 days, unadjusted difference 0 days (95% CI -3 to 0)
  • 90-day survival: 95% vs. 96%, unadjusted difference 1.30% (-3.75% to 6.36%)

Interpretation:

EBP during CBP decreased the incidence of CSA-AKI compared with CBP alone in nonemergent cardiac surgery. These are the first randomized data to demonstrate a clinical benefit to intraoperative EBP. The preceding REMOVE trial failed to show any decrease in overall organ or renal dysfunction in surgically managed infective endocarditis despite successful reduction of circulating cytokine levels with EBP. This may have been due to differences in membrane hemadsorption characteristics or patient-level surgical risk. Although infective endocarditis patients may have hypothetically stood to benefit the most from cytokine reduction, they were much higher acuity than the current cohort with a 30-day mortality over 20%. Exploratory subgroup analyses in SIRAKI02 suggested particular benefit to patients at higher risk for AKI, namely those with hypertension, diabetes, underlying CKD, or depressed left ventricular ejection fraction (LVEF, n = 12). Although EBP reduced CSA-AKI incidence at 7 days, need for short-term renal replacement therapy as well as long-term outcomes such as 3-month survival were unaffected. Future multicenter studies, perhaps in cohorts enriched for vulnerable subgroups such as LVEF, will be needed to confirm the potential utility of intraoperative EBP beyond the immediate postoperative period.

References:

Pérez-Fernández X, Ulsamer A, Cámara-Rosell M, et al. Extracorporeal Blood Purification and Acute Kidney Injury in Cardiac Surgery: The SIRAKI02 Randomized Clinical Trial. JAMA 2024;Oct 9:[Epub ahead of print].

Editorial: Kwong YD, Liu KD. Impact of Adsorptive Blood Purification on Kidney Outcomes. JAMA 2024;Oct 9:[Epub ahead of print].

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention

Keywords: Acute Kidney Injury, Cardiac Surgical Procedures, Cardiopulmonary Bypass, Extracorporeal Circulation


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