Coronary Artery Bypass Grafting (CABG) in Multivessel Disease: Indications, Procedure, Outcomes and Post‑operative Management
1. Introduction
CABG remains the gold standard for revascularisation in patients with multivessel coronary artery disease (MVD) who are symptomatic or have left‑ventricular dysfunction. In India, the prevalence of MVD is high due to late presentation and diabetes burden, making CABG a cornerstone of cardiovascular care. This article details the indications, procedural steps, typical outcomes and comprehensive perioperative management for CABG in MVD.
2. Indications
- Symptomatic multivessel disease: Angina (CCS III–IV) despite optimal medical therapy.
- Left ventricular dysfunction: LVEF < 50% with significant coronary stenosis.
- Triple vessel disease (TVD): Especially when the left main stem is involved.
- Ischemic heart failure: Recurrent hospitalisations or documented myocardial ischemia.
- Patients with diabetes and 2–3 vessel disease where CABG shows superior long‑term survival compared to PCI.
- High SYNTAX score: Anatomical complexity favouring surgical revascularisation.
3. Pre‑operative Assessment
- Echocardiography: Baseline LVEF, wall motion abnormalities, valve function.
- CCTA / Coronary Angiography: Detailed coronary anatomy, graft suitability.
- CT angiogram of thoracic aorta: Assess proximal aortic anatomy for graft anastomosis.
- Cardiac MRI (if available): Viability assessment of myocardium.
- Pre‑operative labs: CBC, electrolytes, renal function, coagulation profile.
- Risk scores: EuroSCORE II, STS score to quantify operative risk.
- Intraoperative TEE: Baseline valve function and LV size.
4. Surgical Technique
- Patient Positioning & Anesthesia: Supine, 30° reverse Trendelenburg; general anesthesia with double lumen endotracheal tube for single lung ventilation if needed.
- Harvesting of Conduits:
- Great saphenous vein (GSV) from the leg – endoscopic or open.
- Internal thoracic artery (ITA) – left ITA is preferred; right ITA used in specific anatomies.
- Radial artery (RA) – harvested with a tourniquet; pre‑op Allen’s test to ensure ulnar collateral circulation.
- Cardiopulmonary Bypass (CPB): Aortic and venous cannulation; aortic cross‑clamp; antegrade or retrograde cardioplegia.
- Graft Strategy:
- Single or multiple arterial grafts – the “arterial dominance” concept.
- Sequential grafting of obtuse marginal branches using a single radial or saphenous segment.
- Composite Y‑grafts (e.g., LITA–RITA to LAD; radial artery to PDA).
- Intraoperative TEE: Verify graft patency, valve function, ventricular filling.
- Weaning & Closure: Gradual wean from CPB; meticulous hemostasis.
5. Typical Outcomes (Indian Data)
- Early mortality: 1–3% in high‑volume centres.
- 30‑day morbidity: Stroke 0.5–1%, renal failure 2–4%, wound infection 3–5%.
- Long‑term survival: 10‑year survival ~70% for LVEF >50%; better than PCI in diabetic patients.
- Re‑infarction rates: <1% at 5 years with arterial grafts.
- Quality of life: Significant improvement in CCS class and NYHA status.
6. Post‑operative Pharmacotherapy (Evidence‑Based)
- Dual Antiplatelet Therapy (DAPT): Aspirin 150–300 mg daily + clopidogrel 75 mg for 12 months (or ticagrelor if indicated).
- Beta‑blockers: Metoprolol 25–100 mg BID to reduce mortality and arrhythmias.
- ACE Inhibitors / ARBs: Enalapril 5–10 mg BID for LV dysfunction or hypertension.
- Statins: Atorvastatin 80 mg daily; high‑intensity therapy to lower LDL <70 mg/dL.
- Anticoagulation: For patients with mechanical valves or atrial fibrillation – warfarin (INR 2–3) or DOACs if suitable.
- Diabetes Management: Insulin therapy intra‑operatively; transition to oral agents post‑op.
- Supplemental Therapies: ACE inhibitors for renal protection; magnesium sulfate if QT prolongation.
7. Perioperative Monitoring & Rehabilitation
- ICU Care: Hemodynamic monitoring, urine output, lactate clearance.
- Extubation: Within 6–12 hours if stable.
- Early Mobilisation: Ambulation by day 2–3; physiotherapy for cardiac rehab.
- Follow‑up Imaging: CTA at 6 months to assess graft patency in high-risk patients.
- Lifestyle Modifications: Smoking cessation, diet counselling (Mediterranean style), exercise regimen 150 min/week.
8. Common Complications & Management
- Stroke: Pre‑op embolic risk assessment; meticulous aortic handling.
- Renal Failure: Avoid nephrotoxic drugs; maintain euvolemia.
- Graft Occlusion: Early detection with Doppler ultrasound; consider percutaneous intervention.
- Infection: Strict aseptic technique; prophylactic antibiotics (cefazolin 2 g).
9. Conclusion
CABG in multivessel disease offers superior long‑term survival and symptom relief when performed in experienced centres with meticulous perioperative care. In India, adherence to evidence‑based protocols and patient‑specific pharmacotherapy can optimise outcomes and reduce morbidity.