What are the necessary pre-procedure preparations for a coronary angiogram?

Preparation for Coronary Angiography

Patients undergoing coronary angiography should continue aspirin therapy, discontinue clopidogrel 5-7 days before elective procedures, discontinue GP IIb/IIIa inhibitors 4 hours before surgery, and manage anticoagulants according to specific timing guidelines while maintaining proper hydration and fasting status. 1

Medication Management

Antiplatelet Therapy

• Aspirin:

  • Continue aspirin (75-150mg daily) throughout the procedure 1
  • Only discontinue in patients at low thrombotic risk and high bleeding risk, particularly for procedures where bleeding in closed spaces is a concern 2

• P2Y12 Inhibitors (Clopidogrel, Prasugrel, Ticagrelor):

  • Discontinue clopidogrel 5-7 days before elective procedures 1
  • For urgent procedures, experienced surgeons may proceed if the increased bleeding risk is acceptable 1
  • For patients with recent stent placement, weigh the risk of stent thrombosis against bleeding risk 2

• GP IIb/IIIa Inhibitors:

  • Discontinue intravenous eptifibatide or tirofiban 4 hours before procedure 1
  • Discontinue abciximab 12 hours before procedure 1

Anticoagulant Therapy

• Unfractionated Heparin (UFH): Continue therapy 1
• Enoxaparin: Discontinue 12-24 hours before procedure 1
• Fondaparinux: Discontinue 24 hours before procedure 1
• Bivalirudin: Discontinue 3 hours before procedure 1
• Warfarin:
  • Traditional approach: Discontinue to reach INR <1.8 3
  • Alternative approach: May proceed with diagnostic angiography with therapeutic INR (2.0-3.0) if using radial access 3
  • Avoid procedures with supratherapeutic INR (>3.0) due to higher complication rates 3

Pre-Procedure Assessment

Laboratory Tests

• Complete blood count
• Renal function tests (creatinine, BUN)
• Coagulation profile (PT/INR, aPTT)
• Electrolytes 4
• High-sensitivity cardiac troponin (for ACS patients) 4

Cardiac Assessment

• 12-lead ECG within 10 minutes of first medical contact for ACS patients 4
• Risk stratification using GRACE or TIMI scores for ACS patients 4
• Echocardiography to evaluate left ventricular function when indicated 4

Hydration and Fasting

• Maintain adequate hydration before procedure to reduce contrast nephropathy risk
• NPO (nothing by mouth) status:
  • No solid food for 6 hours before procedure
  • Clear liquids may be permitted up to 2 hours before procedure

Special Considerations

Beta-Blockers

• Consider administering beta-blockers (preferably metoprolol) to achieve heart rate <65 bpm for optimal imaging 5
• Contraindications: Hypotension, high-degree AV block, decompensated heart failure 5
• Use with caution: Asthma, COPD, vasospastic disease 5

Calcium Channel Blockers

• Diltiazem is an alternative for heart rate control, particularly in patients with:
  • Asthma or bronchospastic disease
  • Heart transplant recipients 5

Nitroglycerin

• Sublingual nitroglycerin may be administered to dilate coronary arteries
• Contraindications: Concurrent use of erectile dysfunction medications, severe anemia
• Use with caution: Aortic stenosis, preload-dependent cardiac conditions 5

Common Pitfalls and Caveats

1. Antiplatelet Discontinuation Risk: Premature discontinuation of dual antiplatelet therapy in patients with recent stent placement can lead to catastrophic stent thrombosis 2

2. Bridging Therapy: Replacing antiplatelet therapy with heparin or LMWH does not adequately protect against coronary artery or stent thrombosis 2

3. Contrast-Induced Nephropathy: Patients with renal insufficiency require adequate hydration before and after the procedure

4. Diabetes Management: Metformin should be held on the day of procedure and for 48 hours afterward due to risk of lactic acidosis when combined with contrast agents

5. Access Site Complications: These are more common with femoral access compared to radial access, especially in anticoagulated patients 3

By following these preparation guidelines, the risk of complications from coronary angiography can be minimized while maintaining optimal diagnostic quality.