Medication Management Prior to Cardiac Catheterization
Direct Answer
In patients with impaired renal function undergoing cardiac catheterization, hold metformin at the time of or prior to the procedure if eGFR is between 30-60 mL/min/1.73m², and restart only after confirming stable renal function at 48 hours post-procedure. 1, 2 For anticoagulation, the approach depends on thrombotic risk and medication type, but most oral anticoagulants should be interrupted with specific timing based on renal function and drug half-life.
Anticoagulation Management
Warfarin
- Stop warfarin 5 days before the procedure in patients requiring interruption, particularly those without mechanical valves or extremely high thrombotic risk 1
- Bridging therapy with unfractionated heparin or low-molecular-weight heparin may be appropriate for patients with mechanical mitral valves or those with additional thrombotic risk factors 1
- Do not routinely use bridging therapy for most patients, as it increases bleeding risk without clear benefit 3
Direct Oral Anticoagulants (DOACs)
- For standard renal function: stop DOACs 48 hours (2 days) before high-risk procedures to ensure minimal residual anticoagulant effect 1
- For dabigatran with CrCl 30-50 mL/min: stop at least 72 hours before the procedure due to renal clearance dependence 1
- Rivaroxaban in severe renal impairment (CrCl 15-30 mL/min): observe closely for bleeding signs, but avoid use if CrCl <15 mL/min 4
- Omit the morning dose on the day of low-risk procedures to perform at trough levels 1
Antiplatelet Agents
- Continue aspirin 81-325 mg in patients already on daily therapy 1
- Clopidogrel should ideally be stopped 5 days before elective procedures if CABG is anticipated, though continuation may be reasonable for diagnostic catheterization 1
- Avoid prasugrel or ticagrelor as part of triple therapy due to increased bleeding risk 1
Medications Requiring Dose Adjustment or Holding in Renal Impairment
Metformin - Critical Priority
- Hold metformin at the time of or prior to contrast administration if eGFR 30-60 mL/min/1.73m² 1, 2
- Also hold in patients with history of hepatic impairment, alcoholism, or heart failure regardless of eGFR 1, 2
- Re-evaluate eGFR 48 hours after the procedure and restart only if renal function is stable 1, 2
- Metformin is contraindicated if eGFR <30 mL/min/1.73m² 2
Rationale: Metformin accumulation in the setting of contrast-induced nephropathy significantly increases the risk of potentially fatal lactic acidosis 2
Renally-Cleared Anticoagulants
- Adjust doses of enoxaparin, fondaparinux, bivalirudin, and GP IIb/IIIa inhibitors in patients with CrCl <60 mL/min 1, 5
- In severe renal failure (CrCl <30 mL/min), these agents may be contraindicated or require substantial dose reduction 5
Other Oral Hypoglycemics
- Long-acting sulfonylureas (glyburide) should not be used at any level of CKD due to prolonged hypoglycemia risk 6
- Short-acting sulfonylureas (glipizide, glimepiride) can be used with caution at reduced doses when eGFR <30 mL/min/1.73m² 6
- SGLT-2 inhibitors should not be used when eGFR <30 mL/min/1.73m² 6
Nephrotoxic Medications to Withhold
Hold NSAIDs 48 hours before the procedure to reduce contrast-induced nephropathy risk 5
- This includes naproxen, ibuprofen, and other non-selective NSAIDs 7, 5
- NSAIDs significantly increase bleeding risk when combined with anticoagulants 7
Other nephrotoxic agents to hold 48 hours pre-procedure: aminoglycosides, amphotericin B 5
Contrast-Induced Nephropathy Prevention Protocol
Hydration Strategy
- Administer isotonic saline (0.9% NaCl) at 1 mL/kg/hour starting 12 hours before and continuing 12-24 hours after contrast 1, 5
- Alternative for lower-risk patients: 250-500 mL before and after the procedure 5
- Exercise extreme caution in heart failure patients—reduce volume and monitor closely for pulmonary edema 5
Contrast Selection and Volume
- Use low-osmolar or iso-osmolar contrast media 1, 5
- Minimize contrast volume to maximum 50 mL for diagnostic procedures in high-risk patients 5
- Calculate contrast volume to creatinine clearance ratio to predict maximum safe volume 1
Post-Procedure Monitoring
- Measure serum creatinine at 48-72 hours post-procedure to detect contrast-induced nephropathy 1, 5
- Measure GFR at 48-96 hours post-procedure 5
Common Pitfalls to Avoid
- Do NOT use N-acetylcysteine—current evidence shows no benefit for preventing contrast-induced nephropathy 1, 5
- Do NOT switch between enoxaparin and UFH or vice versa due to increased bleeding risk 1
- Do NOT aggressively hydrate patients with heart failure and volume overload—use cautious, limited hydration with close monitoring 5
- Do NOT forget to restart anticoagulation post-procedure—nearly 40% of patients in real-world practice fail to restart, exposing them to stroke risk 3
- Do NOT use thiazide diuretics when CrCl <30 mL/min—they are ineffective 5
- Do NOT assume all patients need bridging therapy—it increases bleeding risk without clear benefit in most cases 3
Special Considerations for High-Risk Populations
Severe Renal Impairment (CrCl <30 mL/min)
- Hydration with isotonic saline remains essential 5
- Use iso-osmolar contrast agents 5
- Minimize contrast dose aggressively 5
- Consider alternative imaging if possible
Patients on Multiple Anticoagulants
- Avoid combining fondaparinux with UFH unless necessary to prevent catheter thrombi during PCI 1
- Triple therapy (OAC + dual antiplatelet) should use the lowest effective NOAC dose and include gastric protection with PPI 1