What is Percutaneous Coronary Intervention (PCI)?

What is Percutaneous Coronary Intervention (PCI)?

Percutaneous Coronary Intervention (PCI) is a catheter-based procedure that uses balloon inflation and typically stent placement to open narrowed or blocked coronary arteries, performed through arterial access under local anesthesia without requiring open-heart surgery. 1

Core Definition and Technique

PCI encompasses a broad range of catheter-based techniques for treating coronary artery stenosis, extending beyond the original balloon angioplasty (PTCA) to include:

• Intracoronary stent implantation (both bare-metal and drug-eluting stents) 1
• Balloon angioplasty using controlled inflation of a distensible balloon within the stenotic artery 2
• Atherectomy devices (directional, rotational, and extraction) 1
• Thrombectomy catheters and embolic protection devices 1

The procedure involves introducing a catheter system through a systemic artery (typically femoral or radial) under local anesthesia, advancing it to the coronary arteries, and treating the stenotic lesion. 2

Historical Evolution

The terminology has evolved significantly since the procedure's inception:

• Original term: PTCA (Percutaneous Transluminal Coronary Angioplasty) referred specifically to balloon-only procedures 1
• Current term: PCI encompasses all percutaneous coronary revascularization techniques 1
• Modern practice: Stenting now represents >70% of PCI procedures, while balloon-only PTCA accounts for <30% 1

Clinical Applications

Primary Indications

Stable Coronary Artery Disease:

• Patients with significant stenoses (>70% diameter) and unacceptable angina despite medical therapy 3
• Those with objective evidence of large ischemia in most lesion subsets 3
• When medical therapy cannot be implemented due to contraindications or adverse effects 3

Acute Coronary Syndromes:

• STEMI: Primary PCI is the treatment of choice when performed by experienced teams at PCI-capable hospitals, superior to thrombolysis with lower rates of death, reinfarction, and stroke 3, 4
• NSTE-ACS: Early angiography (≤48 hours) with PCI shows clear benefit in high-risk groups 3

Contraindications and Limitations

The American College of Cardiology recommends against PCI in:

• Patients not meeting anatomic criteria (>50% left main or >70% non-left main stenosis) or physiological criteria for revascularization 3
• Significant left main disease when patient is a CABG candidate 3
• Patients unable to tolerate or comply with dual antiplatelet therapy for the appropriate duration 3

Success Criteria

Angiographic Success

• Pre-stent era: Stenosis reduction to <50% with TIMI grade 3 flow 1
• Current benchmark: Stenosis reduction to <20% with optimal flow, reflecting the improved outcomes with stent technology 1

Procedural Success

Requires angiographic success plus absence of major in-hospital complications:

• Death
• Myocardial infarction (defined as CK-MB elevation >3-5× upper limit of normal or new Q-waves) 1
• Emergency coronary artery bypass surgery 1

Comparison with CABG

CABG is preferred over PCI for:

• Complex 3-vessel disease (SYNTAX score >22) to improve survival 3
• Multivessel disease with diabetes mellitus, particularly when left internal mammary artery grafting to LAD is feasible 3
• Significant left main coronary artery disease in surgical candidates 3

PCI outcomes versus CABG:

• Similar mortality and myocardial infarction rates in appropriate patient subsets 1
• Higher rates of repeat revascularization with PCI 5
• Better symptom relief initially with PCI, though differences diminish over time 3

Procedural Timing

Ad-hoc PCI (performed immediately following diagnostic angiography):

• Now represents 88% of procedures worldwide (increased from 54% in 1990) 2
• Reduces cost, hospital stay, and improves patient convenience 2
• Demonstrates equivalent safety and efficacy compared to staged procedures in contemporary practice 2

Staged PCI (separate session after diagnostic catheterization):

• Previously preferred for complex cases, but modern data shows no significant safety difference 2
• May still be appropriate for multivessel disease requiring planned sequential interventions 1

Critical Success Factors

Operator and facility requirements:

• Higher level of experience required for primary PCI in STEMI than for stable CAD 3
• Experienced operators and catheterization laboratory teams are essential for optimal outcomes 4
• Emergency PCI for STEMI requires expertise in managing complex MI patients, not just technical intervention skills 4

Adjunctive pharmacotherapy:

• Dual antiplatelet therapy (aspirin plus thienopyridine) is mandatory 1
• Glycoprotein IIb/IIIa inhibitors (especially abciximab) provide added value in STEMI 4
• Bivalirudin offers benefits as an anti-thrombin agent 4

Common Pitfalls

• Multivessel intervention at time of primary PCI: Previously contraindicated (Class III) in hemodynamically stable STEMI patients, but recent trials support staged or immediate multivessel PCI in selected cases 1
• Late stent thrombosis: Remains a concern, particularly with drug-eluting stents, requiring prolonged dual antiplatelet therapy 4
• Coronary perforation: Rare but serious complication requiring immediate recognition and treatment 6
• No-reflow phenomenon: Thrombo-embolism consequences requiring specific management strategies beyond structural lesion treatment 4