What is the next step in managing a 61-year-old post-myocardial infarction (MI) patient with a history of coronary artery bypass grafting (CABG) surgery, presenting with intermittent open wounds on the leg that show moderate improvement with doxycycline (a tetracycline antibiotic), but have not fully healed, and also has discoloration of the right lower leg with preserved sensation and pulse?

Management of Post-CABG Leg Wounds with Discoloration

Referral to a wound clinic was the correct decision, and the next critical step is urgent vascular assessment to rule out peripheral artery disease (PAD) or critical limb ischemia (CLI), as this patient's saphenous vein harvest site wounds with discoloration and delayed healing despite antibiotics strongly suggest inadequate arterial perfusion rather than simple infection. 1

Immediate Diagnostic Evaluation Required

The wound clinic must perform:

• Ankle-brachial index (ABI) and toe-brachial index (TBI) measurements to assess arterial perfusion, as discoloration with non-healing wounds in a post-CABG patient with coronary disease suggests concurrent PAD 1
• Duplex ultrasound of lower extremity arteries if ABI is abnormal (<0.90) or if CLI is suspected (ABI <0.40 or TBI <0.70) 1
• Assessment for complete wound healing potential before determining if revascularization is needed 1

The presence of good pulse and sensation is reassuring but does not exclude significant arterial disease, particularly in diabetic patients where calcified vessels can give falsely elevated ABI readings 1

Interdisciplinary Care Team Approach

An interdisciplinary care team should evaluate and provide comprehensive care to achieve complete wound healing and prevent limb-threatening complications. 1 This team must coordinate:

• Vascular surgery consultation if arterial insufficiency is confirmed, as revascularization may be necessary before wounds can heal 1
• Wound care specialists for debridement, appropriate dressing selection, and infection management 1
• Offloading strategies to reduce pressure on affected areas 1
• Optimization of medical therapy including glycemic control if diabetic, as this affects wound healing 1

Antibiotic Management Considerations

The moderate improvement with doxycycline suggests bacterial colonization or infection, but:

• Continue antibiotics only if clinical signs of infection persist (increased exudate, odor, pain, surrounding erythema beyond simple discoloration) 2
• Doxycycline alone will not achieve wound healing if underlying arterial insufficiency exists 1
• Systemic antibiotics should be administered based on clinical infection indicators, not prophylactically for non-healing wounds 2

Wound Care Strategy

While awaiting vascular assessment:

• Use foam dressings (like Mepilex) primarily for exudate control and comfort, not to accelerate healing 2
• Assess wounds at each dressing change for infection signs, exudate characteristics, and healing progress 2
• Do not rely on dressings alone to achieve healing without addressing underlying perfusion issues 2

Critical Decision Point: Revascularization vs. Conservative Management

If vascular assessment reveals significant PAD or CLI:

• Revascularization should be coordinated with wound care efforts to achieve complete wound healing 1
• Endovascular or surgical revascularization may be required depending on lesion characteristics and patient factors 1
• Complete wound healing is the goal, as one study demonstrated 100% limb salvage at 3 years when this was achieved after revascularization 1

If vascular assessment shows adequate perfusion:

• Focus on infection control, offloading, and optimized wound care 1
• Consider negative-pressure wound therapy if primary closure is not feasible 1
• Intermittent pneumatic compression devices may be considered to augment wound healing 1

Common Pitfalls to Avoid

• Do not assume good pulses exclude significant arterial disease, particularly in diabetic or elderly patients with calcified vessels 1
• Do not continue antibiotics indefinitely without documented infection, as this promotes resistance without addressing the underlying healing problem 2
• Do not delay vascular assessment in post-CABG patients with harvest site complications, as saphenous vein harvest can unmask pre-existing PAD 1
• Failing to address underlying perfusion issues will result in continued non-healing regardless of wound care quality 2

Post-CABG Specific Considerations

Given the recent CABG (November 2024):

• Ensure optimal secondary prevention measures including antiplatelet therapy, statin therapy, and blood pressure control, as these affect both cardiac and peripheral vascular outcomes 1
• Physical examination should include assessment of all harvest sites for similar complications 1
• Cardiac rehabilitation participation should not be delayed by leg wounds if patient is otherwise stable, though modifications may be needed 1