What are the management options for a patient with in-stent restenosis, particularly considering surgical revascularization via Coronary Artery Bypass Grafting (CABG)?

Management of In-Stent Restenosis: Surgical Revascularization

For patients with in-stent restenosis (ISR), repeat percutaneous coronary intervention (PCI) with drug-eluting stents (DES) is the first-line treatment, while coronary artery bypass grafting (CABG) should be reserved for patients with symptomatic recurrent diffuse ISR or when anatomy is not amenable to repeat PCI. 1

Primary Treatment Strategy: Repeat PCI with DES

• DES implantation is the Class I, Level A recommendation for treating ISR, demonstrating superior outcomes compared to bare-metal stents or balloon angioplasty alone 1
• Drug-coated balloons are also recommended as a Class I, Level A alternative for ISR treatment, particularly when avoiding an additional metallic layer is desirable 1
• Network meta-analyses consistently show that DES provides the lowest rates of restenosis and target-vessel revascularization among all available treatment modalities 1

When to Consider CABG for ISR

CABG becomes a reasonable option (Class IIa, Level C-EO) in specific clinical scenarios 1:

• Symptomatic recurrent diffuse ISR where repeat PCI has failed or is likely to fail 1
• Multivessel ISR with complex anatomy (SYNTAX score >22) where complete revascularization via PCI is not feasible 1
• ISR in patients with previous CABG where the left internal mammary artery (LIMA) was not previously used—LIMA is the conduit of choice for redo CABG 1
• Extensive ischemia or severe symptoms despite optimal medical therapy with ISR lesions not amenable to repeat PCI 1

Critical Decision-Making Algorithm

Step 1: Assess ISR Pattern and Extent

• Focal ISR (<10mm): Strongly favor repeat PCI with DES or drug-coated balloon 1, 2
• Diffuse ISR (>10mm): Consider repeat PCI first, but CABG becomes more reasonable if recurrent 1, 2
• Multiple vessel ISR: CABG should be strongly considered, especially with diabetes or reduced ejection fraction 1

Step 2: Evaluate Previous Interventions

• First-time ISR: Repeat PCI with DES is preferred 1
• Recurrent ISR (second or third occurrence): CABG becomes increasingly favorable to reduce recurrent events 1
• Previous CABG without LIMA use: Redo CABG with LIMA is indicated 1

Step 3: Consider Patient-Specific Factors

• Surgical risk assessment: Use EuroSCORE or STS score to determine CABG candidacy 1
• Diabetes mellitus with multivessel ISR: CABG preferred over repeat PCI 1
• Left ventricular dysfunction (EF 35-50%): CABG is Class IIa recommendation 1
• Anatomy unsuitable for PCI: CABG becomes necessary 1

Technical Considerations for CABG in ISR

• Coronary endarterectomy with stent removal may be performed in highly selected cases with diffuse disease, though this requires experienced surgical teams and meticulous postoperative anticoagulation 3
• Complete revascularization should be the goal when CABG is chosen, as incomplete revascularization negates the survival benefit 1
• LIMA to LAD grafting remains the gold standard conduit choice and should be prioritized 1

Common Pitfalls to Avoid

• Do not perform CABG for single-vessel ISR without proximal LAD involvement—this is Class III: Harm 1
• Avoid repeat PCI in patients with recurrent diffuse ISR who have already failed multiple interventions, as this leads to ongoing target lesion failure 1, 2
• Do not delay revascularization in patients with extensive ischemia (>10% myocardium) or severe symptoms refractory to medical therapy 1
• Ensure dual antiplatelet therapy compliance before any repeat PCI, as non-compliance increases stent thrombosis risk 1

Adjunctive Therapies

• Brachytherapy may be considered (Class IIb, Level B-NR) for recurrent ISR when other options have been exhausted, though this has largely been superseded by DES and drug-coated balloons 1
• Intravascular imaging (IVUS or OCT) should guide treatment decisions to identify underlying mechanisms such as stent underexpansion, neoatherosclerosis, or fracture 2
• Optimal medical therapy including high-intensity statin therapy, antiplatelet agents, and cardiovascular risk factor control remains essential regardless of revascularization strategy 1

Prognosis and Follow-Up

• ISR carries a 10-year target lesion revascularization rate of approximately 20%, emphasizing the need for aggressive secondary prevention 2
• Recurrent ISR after DES treatment occurs in 5-10% of cases, with higher rates in diabetic patients and those with diffuse disease patterns 1, 2
• CABG for multivessel ISR reduces the need for repeat revascularization compared to repeat PCI, though perioperative risks must be carefully weighed 1