Are there medications that can decrease Acute Kidney Injury (AKI) after cardiac surgery?

Medications to Decrease Acute Kidney Injury After Cardiac Surgery

While there are no specific drugs that directly prevent acute kidney injury after cardiac surgery, several pharmacological strategies can be implemented to reduce the risk of AKI, including discontinuation of ACE inhibitors/ARBs, use of dexmedetomidine, and avoidance of nephrotoxic agents. 1

Risk Assessment and Early Detection

• AKI complicates 22-36% of cardiac surgical procedures, doubling total hospital costs 1
• Urinary biomarkers (tissue inhibitor of metalloproteinases-2 and insulin-like growth factor-binding protein 7) can identify patients at risk of AKI as early as 1 hour after cardiopulmonary bypass 1
• Early identification allows implementation of preventive strategies before permanent damage occurs

Pharmacological Strategies

Medications to Discontinue

• Discontinue angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) for 48 hours after surgery in patients at risk for AKI 1
• Avoid nephrotoxic agents including:
  • Aminoglycosides (unless no suitable alternatives exist) 2
  • Conventional amphotericin B (use lipid formulations if needed) 2
  • NSAIDs (associated with renal dysfunction after cardiac surgery) 1

Potentially Beneficial Medications

• Dexmedetomidine: May reduce AKI after cardiac surgery through its anti-inflammatory and organ-protective effects 1
• Atrial Natriuretic Peptide (ANP): Reduces the need for renal replacement therapy (Number needed to treat: 29) 3
• Brain Natriuretic Peptide (BNP): Associated with a 10% reduction in AKI incidence (Number needed to treat: 11) 3
• Fenoldopam: May reduce need for renal replacement therapy (Number needed to treat: 20) 3

Medications to Avoid

• Furosemide, mannitol, or dopamine should not be given solely for renal protection in aortic repairs 1
• Dopamine causes a significant reduction in creatinine clearance and should be avoided 3
• Piperacillin-tazobactam (Zosyn) combined with vancomycin has higher nephrotoxicity than cefepime plus vancomycin 2

Non-Pharmacological Interventions

• Goal-directed fluid therapy: Use monitoring techniques to guide administration of fluids, vasopressors, and inotropes to avoid hypotension and low cardiac output 1

  • Target specific parameters: blood pressure, cardiac index, systemic venous oxygen saturation, and urine output
  • Consistently demonstrates reduced complication rates and length of stay

• Glycemic control: Treat hyperglycemia (glucose >160-180 mg/dL) with insulin infusion protocols 1

  • Avoid hypoglycemia, especially with tight glucose targets

• Early extubation: Aim for extubation within 6 hours of surgery to reduce complications 1

Implementation Algorithm

1. Preoperative phase:

   • Identify high-risk patients using risk assessment tools
   • Discontinue ACE inhibitors and ARBs 48 hours before surgery
   • Avoid nephrotoxic agents

2. Intraoperative phase:

   • Implement goal-directed fluid therapy
   • Consider dexmedetomidine as part of anesthetic regimen
   • Maintain adequate perfusion pressure during cardiopulmonary bypass

3. Postoperative phase:

   • Monitor urinary biomarkers for early AKI detection
   • Continue avoiding nephrotoxic agents
   • Implement the KDIGO bundle for high-risk patients:
     • Avoid hyperglycemia
     • Optimize volume status and hemodynamic parameters
     • Close monitoring of creatinine and urine output

Common Pitfalls

• Relying on serum creatinine alone for AKI diagnosis delays recognition by 24-48 hours
• Excessive fluid administration can worsen outcomes; use goal-directed approach instead
• Continuing nephrotoxic medications postoperatively due to oversight
• Assuming all diuretics are renoprotective - furosemide and mannitol have not been shown to provide renal protection 1

Despite multiple studies, there remains no single pharmacological agent that consistently prevents AKI after cardiac surgery. The focus should be on risk identification, early detection using biomarkers, and implementing a bundle of preventive strategies rather than relying on a single drug intervention 4, 5.