Coronary Revascularization

Coronary revascularisation — comprising percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) — is a cornerstone of management for obstructive coronary artery disease (CAD). In Australia, over 25,000 PCI procedures and approximately 10,000 CABG operations are performed annually, making revascularisation one of the most common therapeutic interventions in the health system.

The Australian Institute of Health and Welfare (AIHW) reports that ischaemic heart disease remains the leading cause of death in Australia, accounting for over 17,000 deaths in 2022. Coronary revascularisation is indicated across the spectrum of acute coronary syndromes (ACS) — ST-elevation myocardial infarction (STEMI), non-ST-elevation ACS (NSTEACS) — and chronic coronary syndromes (CCS) with refractory symptoms or high-risk anatomy despite optimal medical therapy (OMT).

Contemporary revascularisation practice in Australia is guided by the Cardiac Society of Australia and New Zealand (CSANZ) consensus statements, the European Society of Cardiology (ESC) / European Association for Cardio-Thoracic Surgery (EACTS) myocardial revascularisation guidelines, and National Heart Foundation of Australia (NHF) clinical recommendations. The multidisciplinary Heart Team — comprising interventional cardiologists, cardiac surgeons, imaging specialists, and allied health — is the recommended model for complex decision-making.

Trends in Australian practice include increasing use of newer-generation DES (everolimus- and zotarolimus-eluting), growing adoption of intravascular imaging-guided PCI (IVUS and OCT), expanding CTO programs, and an emerging role for transcatheter techniques in structural heart disease that complement traditional revascularisation.

Indications for PCI

PCI is indicated across a broad clinical spectrum:

• Primary PCI for STEMI: Emergent PCI of the culprit lesion within 120 minutes of first medical contact (FMC) is the gold standard reperfusion strategy. Door-to-balloon time target: ≤90 minutes at PCI-capable centres, ≤120 minutes for transfer patients.
• Early invasive strategy for NSTEACS: Coronary angiography ± PCI within 24 hours for high-risk features (GRACE score >140, dynamic ECG changes, haemodynamic instability, recurrent angina). Very-high-risk features mandate immediate (<2 hours) angiography.
• Stable chronic coronary syndromes: PCI for angina refractory to OMT, or in selected patients with significant stenosis (>90%) and demonstrable ischaemia on functional testing (FFR ≤0.80 or iFR ≤0.89). Routine PCI for stable CAD without ischaemia assessment is not recommended.
• Left main stem (LMS) PCI: Increasingly performed for ostial/shaft LMS disease and selected distal bifurcation LMS disease with low-intermediate SYNTAX score, as an alternative to CABG.

Stent Selection: DES vs BMS

Contemporary DES Platforms Available in Australia

Bifurcation Lesion PCI

Bifurcation lesions account for approximately 15–20% of all PCI. The provisional single-stent strategy (main vessel stenting with provisional side-branch intervention) is the default approach and is supported by the DKCRUSH-V, Nordic-Baltic Bifurcation Study IV, and BBC ONE trial data.

• Provisional stenting (preferred): Stent the main vessel first; only stent the side branch if there >70% residual stenosis, reduced TIMI flow, or dissection after main vessel stenting. Final kissing balloon inflation (FKBI) is recommended if side-branch intervention is performed.
• Planned two-stent techniques: Reserved for true bifurcations with large side branches (≥2.5 mm) with significant disease extending >5 mm into the side branch. Culotte, T-stent, and DK-crush techniques are available. DK-crush has the best evidence for LMS bifurcation (DKCRUSH-V: lower 3-year target-lesion failure vs provisional).
• Intravascular imaging: IVUS or OCT is strongly recommended for bifurcation PCI to optimise stent expansion, detect geographic miss, and confirm side-branch ostial coverage.

Chronic Total Occlusion (CTO) Interventions

CTOs are found in 15–30% of patients undergoing coronary angiography but account for only 5–10% of PCI attempts, reflecting technical complexity. Indications for CTO PCI include refractory angina despite OMT, heart failure with viable myocardium in the CTO territory, and patient preference after informed discussion of risks and benefits.

Rotational Atherectomy

Rotational atherectomy (RA) using the Rotablator® system (Boston Scientific) is indicated for severely calcified coronary lesions that cannot be crossed by a balloon or where adequate stent expansion is unlikely without lesion preparation. The diamond-coated burr ablates calcific plaque into microparticles (<5 μm) that are cleared by the reticuloendothelial system.

Intravascular Imaging-Guided PCI

The ILUMIEN IV (OCT-guided) and RENOVATE-COMPLEX-PCI (IVUS-guided) trials demonstrated that intravascular imaging-guided PCI improves clinical outcomes compared with angiography-guided PCI, particularly in complex lesions (LMCA, long lesions, bifurcations, calcified lesions). CSANZ recommends IVUS or OCT use during complex PCI where available.

• IVUS: Provides cross-sectional vessel imaging with plaque characterisation, measurement of vessel diameter and lesion length, assessment of stent expansion and apposition. Useful for LMS assessment and calcified lesions.
• OCT: Higher resolution (10–20 μm vs 100–200 μm for IVUS), superior for assessing stent strut coverage, dissection flaps, and thrombus. Requires contrast flush. Limited by vessel diameter >3.0 mm for adequate imaging.
• FFR/iFR physiology: Fractional flow reserve (FFR ≤0.80) and instantaneous wave-free ratio (iFR ≤0.89) are the standard invasive physiology assessments. FAME 3 confirmed FFR-guided PCI is superior to angiography-guided PCI in multivessel disease. iFR does not require adenosine, improving patient comfort and reducing procedural time.

CABG remains the revascularisation strategy of choice for several high-risk anatomical and clinical scenarios. Contemporary CABG in Australia is performed with a strong emphasis on arterial grafting — particularly left internal mammary artery (LIMA) to the left anterior descending (LAD) artery — and increasing use of bilateral internal mammary arteries (BIMA) and radial artery grafts.

Class I Indications for CABG

• Left main coronary artery (LMCA) disease: CABG is indicated for significant LMCA stenosis (≥50%) regardless of symptoms. PCI is a reasonable alternative for LMCA disease with SYNTAX score 0–22 and for intermediate SYNTAX (23–32) in selected patients; CABG is preferred for SYNTAX ≥33.
• Triple-vessel disease (3VD): CABG is the preferred revascularisation strategy, particularly with SYNTAX ≥23. The SYNTAX trial 10-year data demonstrated CABG superiority over PCI with first-generation DES for 3VD (mortality: CABG 22% vs PCI 29%, p=0.006 for SYNTAX ≥23).
• Diabetes with multivessel disease: The FREEDOM trial (2012) demonstrated CABG superiority over PCI in diabetic patients with multivessel disease (composite of death, MI, stroke at 5 years: 18.7% CABG vs 26.6% PCI, p=0.005). CABG is Class I recommended for DM with 2- or 3-vessel disease.
• Ischaemic cardiomyopathy with viable myocardium: CABG improves survival in patients with LVEF ≤35% and viable myocardium in ≥4 dysfunctional segments (STICH trial, STICHES 10-year follow-up). Requires viability assessment (PET, dobutamine echo, or cardiac MRI with late gadolinium enhancement).
• Failed PCI or anatomy unsuitable for PCI: Diffuse disease, heavy calcification precluding stent delivery, or failed CTO PCI with ongoing ischaemia.

SYNTAX Score Application

The SYNTAX score is an angiographic grading system that quantifies coronary artery disease complexity based on the number, location, and characteristics of lesions. It is calculated from 12 coronary segments and incorporates lesion dominance, bifurcations, CTOs, calcification, thrombus, and diffuse disease.

Graft Strategy in CABG

Off-Pump vs On-Pump CABG

On-pump CABG with cardiopulmonary bypass remains the standard technique. Off-pump CABG (OPCAB) avoids cardiopulmonary bypass and may benefit patients with heavily atheromatous aorta, severe renal impairment, or high neurological risk. However, the ROOBY and CORONARY trials showed no long-term mortality benefit for OPCAB, with a signal toward lower graft patency. Australian practice: on-pump is the default; OPCAB at surgeon discretion for selected cases.

The Heart Team Approach

The Heart Team meeting should include:

• Interventional cardiologist — review of coronary anatomy, SYNTAX score, feasibility of complete revascularisation by PCI
• Cardiac surgeon — operative risk assessment (EuroSCORE II, STS score), conduit availability, technical feasibility of CABG
• Non-invasive cardiologist or imaging specialist — LV function, viability assessment, functional testing results
• The patient — informed discussion of risks, benefits, alternatives, recovery time, and personal preferences

SYNTAX Score II 2020

The SYNTAX Score II 2020 refines the original anatomical SYNTAX score by incorporating clinical variables to generate individualised predictions of 4-year and 10-year mortality for PCI vs CABG. Variables include:

• Anatomical SYNTAX score
• Age
• Creatinine clearance (Cockcroft-Gault)
• Left ventricular ejection fraction (LVEF)
• Chronic obstructive pulmonary disease (COPD)
• Peripheral vascular disease (PVD)
• Sex
• Diabetes mellitus

Key Trial Evidence: PCI vs CABG

Surgical Risk Assessment

Surgical risk stratification is essential for the Heart Team. Two validated scoring systems are used in Australian practice:

• EuroSCORE II: Predicts in-hospital mortality for cardiac surgery. Variables include age, sex, renal function, cardiac status, recent MI, pulmonary disease, neurological disease, extracardiac arteriopathy, active endocarditis, critical preoperative state, diabetes on insulin, NYHA class, CCS class 4 angina, LV function, pulmonary hypertension, urgency, weight of intervention, and thoracic aorta surgery.
• STS Risk Score (Society of Thoracic Surgeons): Predicts operative mortality and morbidity for isolated CABG. Widely used in Australian cardiac surgery units. An STS predicted mortality >5% identifies high-risk patients.
• Frailty assessment: Gait speed, grip strength, cognitive function (Montreal Cognitive Assessment), and nutritional status. Frailty is an independent predictor of poor post-CABG outcomes and should be incorporated into decision-making.

Patient Preferences and Shared Decision-Making

Patient-centred care requires that revascularisation decisions incorporate individual values and preferences:

• Recovery time: PCI typically allows return to normal activity within 1–2 weeks; CABG requires 6–12 weeks for sternal healing and full recovery.
• Stroke risk: CABG carries a 1–2% perioperative stroke risk (higher in elderly, aortic atherosclerosis); PCI stroke risk is <0.5%.
• Repeat revascularisation: PCI has higher rates of repeat revascularisation (5–15% at 5 years) vs CABG (2–5%).
• DAPT commitment: PCI mandates prolonged DAPT; CABG does not require DAPT post-operatively (unless recent ACS or LIMA graft concern).
• Angina relief: CABG provides more complete and durable angina relief, especially with multivessel disease.

Stent Thrombosis

Management of stent thrombosis:

1. Emergency coronary angiography with aspiration thrombectomy (Export® catheter)
2. Intravascular imaging (IVUS or OCT) to identify the mechanism — underexpansion, malapposition, geographic miss, edge dissection, neoatherosclerosis
3. Treat the underlying cause: high-pressure balloon dilatation, additional stenting for dissection or geographic miss
4. GP IIb/IIIa inhibitor (abciximab or eptifibatide) if not already administered
5. Confirm or escalate antiplatelet therapy: switch from clopidogrel to ticagrelor (Brilinta®) 90 mg BD or prasugrel (Effient®) 10 mg OD (if not already on these agents)
6. Check platelet function testing (VerifyNow® P2Y12 assay) if clopidogrel resistance suspected — available at major Australian centres
7. Extended DAPT consideration: ≥12 months (or lifelong) if stent thrombosis occurred despite DAPT

In-Stent Restenosis (ISR)

In-stent restenosis is the recurrence of significant luminal narrowing (>50%) within a stented segment. Presentation ranges from asymptomatic (detected on routine surveillance) to ACS. ISR rates with newer-generation DES are 3–8%, compared with 20–30% for BMS.

Periprocedural Myocardial Infarction (Type 4a MI)

Type 4a MI is defined as an elevation of cardiac troponin (>5× 99th percentile upper reference limit [URL]) within 48 hours of PCI, with either (a) symptoms of myocardial ischaemia, (b) new ischaemic ECG changes, (c) angiographic loss of patency of a major coronary artery, or (d) imaging evidence of new loss of viable myocardium. The incidence ranges from 5–30% depending on the definition used and the complexity of the lesion.

• Prevention: Adequate pre-treatment with DAPT, intravascular imaging to avoid geographic miss, careful side-branch protection during bifurcation PCI, distal protection devices for SVG interventions, and avoidance of slow/no-reflow with appropriate lesion preparation.
• Post-PCI troponin surveillance: All patients should have serial high-sensitivity troponin (hs-cTn) measured at 6–12 hours post-PCI. Routine post-PCI troponin elevation (1–5× URL) is common and generally benign; elevation >5× URL with clinical correlate requires further investigation.
• Management: Angiographic re-look if troponin rise is significant with ECG or haemodynamic changes. Treat the cause (side-branch occlusion, distal embolisation, no-reflow). GP IIb/IIIa inhibitors and intracoronary vasodilators (nitroprusside, adenosine, verapamil) for no-reflow.

Vascular Access Complications

Periprocedural Antiplatelet and Anticoagulation Strategy

Optimal pharmacotherapy is critical to minimise both ischaemic and bleeding complications:

DAPT Duration Recommendations

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