What's New in the 2021 Guidelines
This update consolidates the 2011 PCI, 2011 CABG, and 2015 PCI-STEMI guidelines with new evidence through May 2021, emphasizing patient-centered shared decision-making and Heart Team multidisciplinary approach.
Key Updates
- Reinforced Heart Team approach for complex CAD, particularly left main and multivessel disease
- Updated evidence on SYNTAX score utility for CABG vs. PCI decisions
- Expanded recommendations on intravascular imaging (IVUS, OCT) for PCI guidance
- Refined timing strategies for NSTE-ACS invasive angiography (early vs. delayed)
- Clarified DAPT duration, statin intensity, and blood pressure targets post-revascularization
- Addressed special populations: diabetes, CKD, elderly, prior CABG, low EF, cardiogenic shock
Indications for Revascularization
Stable Ischemic Heart Disease (SIHD)
Revascularization with PCI or CABG is indicated if:
- Significant stenosis (≥70% diameter or ≥50% left main)
- Objective evidence of ischemia (functional testing or imaging)
- Failed or inadequate medical therapy (GDMT)
- Symptoms amenable to revascularization
STEMI
Immediate Reperfusion Strategy: PCI is preferred within 12 hours of symptom onset for improved survival. CABG is an alternative if PCI is not feasible and there are mechanical complications (VSD, papillary muscle rupture, or severe mitral regurgitation).
NSTE-ACS
Timing of Invasive Angiography
Immediate (within 2 h): Cardiogenic shock, hemodynamic instability, refractory angina
Early (≤24 h): High-risk features (GRACE score >140, biomarker elevation)
Routine (<48 h): Initially stabilized, intermediate or low-risk patients
The Heart Team and Shared Decision-Making
Recommendation (Class I)
For patients with unclear optimal treatment strategy, a multidisciplinary Heart Team including interventional cardiology, cardiac surgery, and clinical cardiology is recommended to optimize patient outcomes.
Heart Team Composition
- Interventional cardiologist
- Cardiac surgeon
- Clinical cardiologist
- Anesthesiologist (for preoperative assessment)
- Advanced practice provider / nurse specialist
- Patient and family support members
Key Considerations by Heart Team
| Anatomic |
Procedural |
Patient Factors |
| Left main disease |
Surgical risk (STS score) |
Age, life expectancy |
| Multivessel disease |
Access site issues |
Frailty, comorbidities |
| SYNTAX score |
Operator expertise |
DAPT tolerance, preferences |
| Diabetes |
Graft availability |
Cognitive status, education |
PCI vs. CABG Decision Framework
SYNTAX Score
The SYNTAX score quantifies angiographic CAD complexity. In patients with multivessel disease or left main CAD, SYNTAX score guides choice:
- Low (≤22): Equivalent outcomes with PCI or CABG
- Intermediate (23-32): Heart Team discussion; both reasonable
- High (≥33): CABG preferred over PCI for mortality benefit
Left Main Disease
CABG Recommendations
- CABG is recommended to improve survival in SIHD with significant left main CAD
- PCI may be reasonable in selected patients with low-to-intermediate complexity and favorable anatomy
- Complex left main bifurcation: CABG is favored; PCI requires expertise and intravascular imaging
Diabetes
Class I (CABG with LIMA to LAD): Patients with diabetes and multivessel CAD with LAD involvement; CABG reduces mortality and repeat revascularization vs. PCI over long term (1–8 years).
Triple-Vessel Disease
CABG Preferred: Patients with EF <50%, significant stenosis in 3 major coronary arteries, and complex anatomy (SYNTAX ≥33). PCI may be considered in selected stable patients with anatomy suitable for complete revascularization.
PCI: Technical Considerations and Imaging
Drug-Eluting Stents (DES)
Class I: DES should be used in preference to BMS for all lesions to reduce restenosis, MI, and stent thrombosis. Newer-generation DES have superior safety and efficacy profiles.
Intravascular Imaging (IVUS / OCT)
Recommended Uses
IVUS (Class IIa): Left main or complex coronary stenosis to guide lesion assessment, stent sizing, and post-PCI minimum lumen area
OCT (Class IIa): Alternative to IVUS for procedural guidance; superior for ostial disease and left main assessment
Stent Failure (Class IIa): IVUS or OCT to determine mechanism and guide repeat intervention
Physiologic Assessment (FFR / iFR)
FFR (Class I): In stable patients with angiographically intermediate lesions (40–70% diameter stenosis), FFR is recommended to guide decision to perform PCI vs. defer to medical therapy.
iFR (Class IIa): Instantaneous wave-free ratio is a reasonable alternative to FFR for intermediate lesions when FFR is not feasible.
Complete Revascularization
Multivessel PCI: Strategy depends on clinical presentation. In STEMI, staged PCI of non-culprit arteries is reasonable to reduce recurrent events. In stable disease, complete revascularization is preferred when anatomy permits.
Post-Revascularization Pharmacotherapy and Monitoring
Secondary Prevention
Essential Medications
- High-Intensity Statin: Atorvastatin 80 mg or rosuvastatin 20–40 mg daily; target LDL <70 mg/dL (or <55 if very high-risk)
- Aspirin: 75–100 mg daily indefinitely
- P2Y12 Inhibitor (DAPT): As specified; duration based on setting (STEMI, NSTE-ACS, stable)
- Beta-blocker: Metoprolol, carvedilol, or bisoprolol; target resting HR 50–60 bpm in post-MI patients
- ACE-I or ARB: For EF ≤40%, diabetes, or hypertension
- Blood Pressure Target: <130/80 mmHg in most patients; individualize in elderly
Cardiac Rehabilitation
Class I: Enrollment in a supervised cardiac rehabilitation program with exercise, risk factor modification, education, and psychosocial support is recommended for all patients after revascularization to improve adherence, reduce symptoms, and lower recurrent event risk.
Follow-Up Monitoring
Surveillance Strategy
2–4 weeks post-PCI/CABG: Clinical assessment, medication review
3 months: Repeat lipid panel, renal function, glucose; echocardiography if EF reassessment needed
6–12 months: Functional testing only if symptoms or clinical indication
Routine surveillance angiography not recommended in absence of symptoms
Special Populations and Clinical Scenarios
Diabetes Mellitus
Patients with diabetes and multivessel CAD, especially with LAD involvement, benefit more from CABG than PCI for long-term mortality reduction (Class I, LIMA to LAD). PCI is reasonable in selected patients with amenable anatomy and good compliance with DAPT.
Chronic Kidney Disease (CKD)
Risk Mitigation
- Adequate hydration and volume assessment pre-angiography
- Minimize contrast volume; use iso-osmolar or low-osmolar agents
- Avoid N-acetyl-cysteine and prophylactic dialysis (limited benefit)
- Radial artery approach preferred to reduce bleeding complications
- Avoid routine revascularization in asymptomatic stable CAD (Class III: No Benefit)
Elderly Patients (≥75 Years)
Personalized Approach: Treatment decisions should be individualized based on life expectancy, cognitive function, frailty, and patient preferences. Both PCI and CABG can be safe options when selected carefully with shared decision-making.
Prior CABG / Repeat Revascularization
Recommendations
- Percutaneous intervention of native vessel or vein graft preferred over redo CABG
- LIMA patency should be assessed; avoid manipulation if patent
- Complex anatomy or poor distal targets may warrant redo CABG (with IMA conduit if available)
Cardiogenic Shock and Multivessel PCI
CULPRIT Strategy (Class I): In STEMI with cardiogenic shock and multivessel disease, primary PCI of culprit artery only is recommended, with staged revascularization of non-culprit lesions after stabilization. Immediate multivessel PCI is not beneficial.
Low Ejection Fraction (EF ≤35%)
CABG with LIMA to LAD (Class I): Recommended for significant left main or multivessel CAD with EF <35% and objective ischemia to improve survival vs. medical therapy alone.