Interventional cardiology has transformed the management of coronary artery disease. Understanding when and how to intervene is crucial for optimal patient outcomes.
Indications for PCI
Class I Indications (Strongest Evidence)
- STEMI: Primary PCI within 90 minutes of first medical contact
- Cardiogenic shock: Regardless of time from symptom onset
- Refractory angina: Despite optimal medical therapy
Class IIa Indications
- High-risk stable angina: Failed medical therapy
- Significant left main disease: In patients not suitable for CABG
- Multi-vessel disease: With heart failure and reduced EF
Class III (Not Recommended)
- Asymptomatic patients: No evidence of ischemia
- Single vessel disease: With successful medical therapy
- Low-risk stable angina: Without significant ischemia
Stent Technology
Bare Metal Stents (BMS)
- Restenosis rate: 20-30%
- Antiplatelet therapy: 1 month minimum
- Use: Limited, mainly for large vessels
Drug-Eluting Stents (DES)
- Restenosis rate: 5-10%
- Antiplatelet therapy: 6-12 months minimum
- Types: Everolimus, zotarolimus, biolimus
Key Point: DES has dramatically reduced restenosis and is now the default choice for most PCI procedures.
Bioresorbable Scaffolds
- Mechanism: Temporary scaffolding, then absorbed
- Status: Limited use due to scaffold thrombosis concerns
- Future: Next-generation scaffolds under investigation
Antiplatelet Therapy
Dual Antiplatelet Therapy (DAPT)
| Duration | Indication |
|---|---|
| 1 month | High bleeding risk |
| 6 months | Standard risk |
| 12 months | High thrombotic risk |
Agents
- Aspirin: 81 mg daily, lifelong
- P2Y12 inhibitor: Clopidogrel, ticagrelor, or prasugrel
- Ticagrelor: Preferred for ACS (PLATO trial)
- Prasugrel: Faster onset, more potent (TRITON-TIMI 38)
Complex PCI Scenarios
Left Main Disease
- SYNTAX score: Guides revascularization strategy
- Low syntax (0-22): PCI or CABG equivalent
- High syntax (>32): CABG preferred
Chronic Total Occlusions (CTO)
- Success rates: 70-90% in experienced centers
- Techniques: Antegrade, retrograde, hybrid
- Benefits: Improved angina, LV function
Bifurcation Lesions
- Medina classification: Describes bifurcation anatomy
- Strategies: Provisional stenting vs two-stent techniques
- Jailed wire technique: Common approach
Invasive Physiology
Fractional Flow Reserve (FFR)
- Measurement: Pressure wire across stenosis
- Cutoff: FFR ≤ 0.80 indicates ischemia
- Evidence: FAME trials showed improved outcomes
Instantaneous Wave-Free Ratio (iFR)
- Measurement: Diastolic-only pressure ratio
- Cutoff: iFR ≤ 0.89
- Advantage: No adenosine required
Complications and Management
Bleeding
- Access site: Radial > femoral (RIVAL trial)
- Bivalirudin: Alternative to heparin
- TR Band: For radial hemostasis
Contrast-Induced Nephropathy
- Prevention: Hydration, minimize contrast
- Risk factors: CKD, diabetes, heart failure
- Monitoring: Creatinine at 24-48 hours
Stent Thrombosis
- Acute: < 24 hours
- Subacute: 1-30 days
- Late: 1-12 months
- Very late: > 12 months
Quality Metrics
| Metric | Target |
|---|---|
| Door-to-balloon time (STEMI) | < 90 minutes |
| Radial access | > 80% |
| FFR/iFR use | > 30% |
| DAPT compliance | > 90% |
Conclusion
Interventional cardiology continues to evolve with new technologies and techniques. Understanding indications, techniques, and complications will help you provide optimal care for your patients.
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