Are elevated Aspartate Aminotransferase (AST) of 64 and Alanine Aminotransferase (ALT) of 65 acceptable for surgery?

Preoperative Clearance with Mildly Elevated Transaminases

AST 64 U/L and ALT 65 U/L represent mild elevations (<5× upper limit of normal) that do not contraindicate surgery, as these levels are commonly observed postoperatively and are not associated with adverse surgical outcomes. 1

Evidence Supporting Surgical Clearance

The most compelling evidence comes from liver transplantation guidelines, which demonstrate that even very high donor transaminases (>1,000 IU/L) do not predict poor post-transplant outcomes. A large cohort study of >5,000 liver transplant recipients found that elevated donor ALT and AST levels had no impact on early or overall graft loss or recipient survival on multivariate analysis. 1 This finding remained consistent even when analyzing subgroups including steatotic livers and donors with increasing ALT at donation. 1

Severity Classification

Your transaminase levels fall into the "mild" category:

• Mild elevation is defined as <5× upper limit of normal (ULN) 2, 3
• Using standard reference ranges (ALT: 29-33 IU/L for males, 19-25 IU/L for females; AST: similar ranges), your values represent approximately 2× ULN 2, 3
• This is far below the threshold requiring urgent intervention (>5× ULN) 4

Postoperative Context

Surgery itself commonly causes transaminase elevations that exceed your current levels:

• After laparoscopic cholecystectomy, ALT increases to 87 U/L at 24 hours and peaks at 99 U/L at 72 hours postoperatively in patients with preoperatively normal values 5
• AST similarly increases to 83 U/L at 24 hours and 104 U/L at 72 hours after laparoscopic procedures 5
• CO2 pneumoperitoneum is the primary mechanism for these changes, which are clinically insignificant 5
• Values normalize within 7-10 days postoperatively 5

Preoperative Considerations

Before proceeding, verify these factors to optimize safety:

• Exclude active liver disease: Check for jaundice, ascites, or coagulopathy (INR, albumin, bilirubin) 1
• Assess synthetic function: Normal albumin, bilirubin, and INR indicate preserved liver function despite mild transaminase elevation 3
• Review medications: Discontinue non-essential hepatotoxic medications if feasible 3
• Document alcohol use: AST:ALT ratio <1 (your case: 64/65 = 0.98) suggests non-alcoholic etiology rather than alcoholic liver disease (which shows ratio >2:1) 2, 4

Specific Surgical Considerations

For cardiac surgery (CABG), additional monitoring is warranted:

• Active or chronic liver disease is a contraindication to perioperative statin therapy, but mild transaminase elevation alone does not constitute active liver disease 1
• Approximately 2% of statin users develop elevated transaminases, but these elevations are not associated with permanent hepatotoxicity 1
• Postoperative glucose control targeting <180 mg/dL is indicated regardless of transaminase levels 1

Common Pitfalls to Avoid

• Do not delay surgery for mild transaminase elevations without evidence of synthetic dysfunction 1
• Do not assume AST elevation is purely hepatic: AST is present in cardiac muscle, skeletal muscle, and erythrocytes; check creatine kinase if muscle injury is suspected 2, 6
• Do not order extensive hepatic workup preoperatively unless synthetic function is impaired or values are >5× ULN 3, 4

Postoperative Monitoring

Plan for expected transaminase increases after surgery:

• Recheck liver enzymes only if clinical signs of hepatic dysfunction develop (jaundice, coagulopathy, encephalopathy) 1
• Transient elevations to 2-3× your current values are expected and clinically insignificant 5, 7
• Values should normalize within 2-4 weeks postoperatively 5, 7