For an obese patient (>100 kg) who recently underwent percutaneous coronary intervention and is on dual antiplatelet therapy, how should fraxiparin be dosed and managed as a bridge before a colonoscopy?

Fraxiparin Dosing for Obese Post-PCI Patients Before Colonoscopy

For obese patients (>100 kg) on dual antiplatelet therapy after PCI requiring colonoscopy, fraxiparin (nadroparin) 0.6 mL is insufficient—weight-based dosing of LMWH is not recommended as bridging therapy, and the focus should be on carefully timed interruption of P2Y12 inhibitors while continuing aspirin. 1

Critical Context: Bridging is Not Recommended

• Routine bridging with LMWH, glycoprotein IIb/IIIa inhibitors, or other parenteral anticoagulation is explicitly not recommended for patients interrupting antiplatelet therapy for procedures. 1, 2
• The 2021 ACC Expert Consensus states that only a small subset of patients with extremely high thromboembolic risk should be considered for bridging with parenteral anticoagulation, and this applies specifically to warfarin bridging until INR is therapeutic—not to antiplatelet interruption. 1
• There is no evidence that heparin or LMWH bridging reduces thrombotic events when antiplatelet therapy is interrupted, and it significantly increases bleeding risk. 1, 3

Proper Management Strategy for This Clinical Scenario

Timing Considerations Based on Stent Type and Timing

If within 6 months of drug-eluting stent (DES) placement:

• Defer the colonoscopy if clinically possible, as the risk of stent thrombosis is highest in this period. 1
• If colonoscopy cannot be deferred, maintain both aspirin and P2Y12 inhibitor throughout the procedure if the endoscopist agrees. 1, 4

If 6-12 months post-DES or >1 month post-bare metal stent:

• Stop the P2Y12 inhibitor 5-7 days before colonoscopy (clopidogrel requires 5-7 days for platelet function recovery; prasugrel and ticagrelor have similar timelines). 1, 4
• Continue aspirin throughout the perioperative period. 1, 2
• Resume P2Y12 inhibitor with a loading dose (clopidogrel 600 mg) immediately after colonoscopy once hemostasis is confirmed. 1, 4

Special Considerations for Obesity (BMI >30 kg/m²)

The 2024 ESC consensus on body mass and antithrombotic therapy provides specific guidance:

• In obese patients (class ≥2, BMI >35), standard clopidogrel dosing may result in inadequate platelet inhibition due to altered pharmacokinetics. 1
• Consider doubling the maintenance dose of clopidogrel (150 mg daily) in obesity class ≥2 patients to achieve adequate platelet inhibition, though this is based on pharmacodynamic rather than clinical outcome data. 1
• For obese patients undergoing PCI, a longer duration of triple antithrombotic therapy and individualization of dosing intervals may be appropriate. 1
• There is no recommendation to use LMWH bridging in obese patients—the focus remains on optimizing oral antiplatelet therapy. 1

Multidisciplinary Discussion Required

• Mandatory consultation with the interventional cardiologist who performed the PCI before any antiplatelet interruption. 1, 2
• Assess specific thrombotic risk factors: multiple stents, bifurcation lesions, left main involvement, incomplete revascularization, diabetes, or history of prior stent thrombosis all increase risk. 2
• Colonoscopy is considered a high-risk bleeding procedure, which influences the decision-making. 1

Why Fraxiparin 0.6 mL is Not the Answer

• The fixed dose of 0.6 mL (approximately 5,700 IU anti-Xa) is designed for VTE prophylaxis, not as bridging for antiplatelet interruption. 1
• Weight-based LMWH dosing for bridging lacks evidence of benefit and increases bleeding complications. 1, 3
• The pharmacologic properties of LMWH do not adequately substitute for P2Y12 inhibition in preventing stent thrombosis. 1

Common Pitfalls to Avoid

• Never stop both aspirin and P2Y12 inhibitor simultaneously—this dramatically increases stent thrombosis risk with a hazard ratio of 161 for MI or death. 1
• Do not perform ad hoc procedures without proper Heart Team discussion in complex cases. 1
• Avoid assuming standard dosing is adequate in obese patients—pharmacodynamic responses are altered. 1
• Do not use bridging therapy routinely—it increases bleeding without reducing thrombotic events. 1