What are the indications and procedures for using excimer lasers in coronary applications, such as laser angioplasty, for treating coronary artery disease?

Coronary Application of Excimer Laser

Excimer laser coronary angioplasty should not be used routinely during percutaneous coronary intervention but may be considered as a bailout strategy for fibrotic or moderately calcified lesions that cannot be crossed or dilated with conventional balloon angioplasty. 1

Evidence-Based Recommendations

The American College of Cardiology provides clear guidance on excimer laser use in coronary interventions:

• Class IIb recommendation (may be considered): Excimer laser angioplasty for fibrotic or moderately calcified lesions that cannot be crossed or dilated with conventional balloon angioplasty 1
• Class III recommendation (should not be performed): Routine use of laser angioplasty during PCI 1

The evidence supporting these recommendations is compelling—randomized controlled trials have consistently failed to demonstrate improved clinical or angiographic outcomes compared to conventional techniques. 1

Clinical Algorithm for Decision-Making

Follow this stepwise approach when considering excimer laser:

1. First-line approach: Attempt conventional balloon angioplasty 1
2. Assess failure: Determine if the lesion is fibrotic or moderately calcified AND cannot be crossed or dilated 1
3. Consider laser only if: Both conditions above are met 1
4. Alternative considerations: For heavily calcified lesions, rotational atherectomy carries a Class IIa recommendation (stronger evidence) 2

Specific Clinical Applications

While the overall evidence is disappointing, excimer laser may have utility in select scenarios:

• Fibrotic lesions resistant to conventional approaches that cannot be crossed with standard equipment 1
• Moderately calcified lesions where balloon catheters fail to cross or dilate 1
• Chronic total occlusions to facilitate modification of the proximal cap, though this remains an advanced technique 3
• Undilatable stents where a stent was deployed but remains under-expanded 3

Evidence Base and Limitations

The evidence against routine laser use is robust:

• The AMRO trial (103 patients with functional or total occlusions) showed no benefit: angiographic success was 65% with laser-assisted balloon angioplasty versus 61% with balloon alone, with higher restenosis rates (66.7% vs 48.5%) 4
• A larger randomized trial (308 patients) demonstrated no advantage: net gain in minimal lumen diameter was actually lower with laser (0.40 mm vs 0.48 mm), and restenosis rates trended higher (51.6% vs 41.3%) 5
• Registry data from 3,000 consecutive patients showed procedural success of 90% but with complications including perforation (1.2%), Q-wave MI (2.1%), and emergency bypass surgery (3.8%) 6

Critical Pitfalls to Avoid

• Do not use laser routinely: The evidence clearly shows no benefit and potential harm with routine application 1, 5
• Recognize that laser is almost always followed by balloon angioplasty: In trials, 98% of laser procedures required subsequent balloon angioplasty, making it an adjunctive rather than standalone therapy 5
• Consider rotational atherectomy first for calcified lesions: This modality has stronger evidence (Class IIa) for heavily calcified lesions compared to laser's Class IIb recommendation 2
• Perforation risk: Early registry data showed 1.2% perforation rates, though this improved to 0.4% with experience 6

Positioning Among Other Plaque Modification Techniques

The hierarchy of evidence for lesion preparation is important:

• Rotational atherectomy: Class IIa recommendation for heavily calcified lesions that cannot be crossed or adequately dilated 2
• Excimer laser: Class IIb recommendation for fibrotic or moderately calcified lesions 1
• Cutting balloon: Class IIb recommendation for in-stent restenosis or ostial lesions 1