Dr. Luc TambeurDr. Luc Tambeur

Coronary artery Coronary artery bypass graftingbypass graftingCABG - OPCABCABG - OPCAB

Coronary artery diseaseCoronary artery disease

Definition:Definition: Narrowing of the coronary arteriesNarrowing of the coronary arteries Caused by thickening and loss of elasticity Caused by thickening and loss of elasticity

of the arterial wallsof the arterial walls Limiting blood flow to the myocardiumLimiting blood flow to the myocardium

Flow reserve (effort)Flow reserve (effort) At restAt rest OcclusionOcclusion

Coronary artery diseaseCoronary artery disease

Morphology and processes:Morphology and processes: Focal intimal accumulation of lipids, blood elements, Focal intimal accumulation of lipids, blood elements,

fibrous tissue, calcium etc. with associated changes fibrous tissue, calcium etc. with associated changes in the mediain the media

→ → PlaquePlaque → → StenosisStenosis Regression of plaque and collateral formationRegression of plaque and collateral formation Plaque rupture and thrombosisPlaque rupture and thrombosis Usually affects multiple coronaries simultaneously, Usually affects multiple coronaries simultaneously,

proximally and at bifurcationsproximally and at bifurcations

Myocardial infarctionMyocardial infarction

Imbalance between oxygen supply and Imbalance between oxygen supply and demanddemand

Myocardial necrosis starts after 20 minutesMyocardial necrosis starts after 20 minutes Border zoneBorder zone Reperfusion within 3-4 hours can limit the Reperfusion within 3-4 hours can limit the

extent of myocardial necrosisextent of myocardial necrosis Scarring. LV systolic and diastolic dysfunction. Scarring. LV systolic and diastolic dysfunction.

Chronic heart failure.Chronic heart failure.

DiagnosisDiagnosis

Symptoms: Angina pectoris, acute Symptoms: Angina pectoris, acute myocardial infarction, chronic heart myocardial infarction, chronic heart failure, sudden death, incidental finding failure, sudden death, incidental finding on ECGon ECG

Noninvasive tests to identify and quantify Noninvasive tests to identify and quantify CAD and sequelae: ECG, CXR, Labs, CAD and sequelae: ECG, CXR, Labs, Exercise testing, Nuclear scans, Exercise testing, Nuclear scans, Echocardiography, CT (CaEchocardiography, CT (Ca++++))

DiagnosisDiagnosis

Associated conditionsAssociated conditions Atherosclerosis: carotids, PADAtherosclerosis: carotids, PAD

Definitive diagnosis: extent, distribution Definitive diagnosis: extent, distribution and severity of and severity of anatomicanatomic coronary artery coronary artery diseasedisease Coronary angiographyCoronary angiography New modalities: CT (MRI)New modalities: CT (MRI)

Coronary angiographyCoronary angiography

Grading of stenoses:Grading of stenoses: Moderate: 50% diameter = 75% cross-Moderate: 50% diameter = 75% cross-

sectional area losssectional area loss Severe: 67% diameter = 90% cross-Severe: 67% diameter = 90% cross-

sectional area losssectional area loss

Distribution:Distribution: Single system / two system / three systemSingle system / two system / three system Left mainLeft main

Coronary anatomyCoronary anatomy

Indications for surgeryIndications for surgery

Comparative benefit of surgery relative to no Comparative benefit of surgery relative to no treatment / medical treatment / PCItreatment / medical treatment / PCI

Enormous variability in CAD, impacting on risk Enormous variability in CAD, impacting on risk calculation calculation → patient-specific predictions→ patient-specific predictions

General indications:General indications: Left main or left main equivalentLeft main or left main equivalent 3 system disease3 system disease 2 system disease with severe prox. LAD and LVEF 2 system disease with severe prox. LAD and LVEF

< 50% or ischemia on non-invasive testing< 50% or ischemia on non-invasive testing 1 or 2 system disease with large area of viable 1 or 2 system disease with large area of viable

myocardium and high-risk criteriamyocardium and high-risk criteria

Bypass graftingBypass grafting

Full sternotomy and CPB (HLM):Full sternotomy and CPB (HLM):

CABGCABG

Full sternotomy, no CPB:Full sternotomy, no CPB:

OPCABOPCAB

Small sternotomy, parasternal access, Small sternotomy, parasternal access, thoracotomy, with or without CPB:thoracotomy, with or without CPB:

e.g.e.g. MIDCABMIDCAB

Bypass graftingBypass grafting

CABG = Golden standard and still most CABG = Golden standard and still most widely used (STS database widely used (STS database ± 80%)± 80%)

Objective: complete revascularisation by Objective: complete revascularisation by bypassing all severe stenoses in all bypassing all severe stenoses in all affected coronary branches with ≥ 1-1.5 affected coronary branches with ≥ 1-1.5 mm diametermm diameter

Most widely used conduits: LIMA, RIMA, Most widely used conduits: LIMA, RIMA, SVG, radial artery, gastro-epiploic arterySVG, radial artery, gastro-epiploic artery

ConduitsConduitsLIMA / RIMALIMA / RIMA

ConduitsConduitsSVGSVG

ConduitsConduitsRadialRadial

ConduitsConduitsGastro-epiploicGastro-epiploic

Conduit configurationsConduit configurations

Endarter-Endarter-ectomyectomy

CABGCABG

Median sternotomyMedian sternotomy Conduit harvestingConduit harvesting Heparin, cannulation and CPB with mild to moderate Heparin, cannulation and CPB with mild to moderate

hypothermiahypothermia Cross-clamping of the aorta and cardioplegiaCross-clamping of the aorta and cardioplegia Distal anastomoses. Rewarming started.Distal anastomoses. Rewarming started. Cross-clamp removed. Proximal anast. using a partially Cross-clamp removed. Proximal anast. using a partially

occluding clamp. Clamp removed. De-airing. occluding clamp. Clamp removed. De-airing. CPB discontinued, cannulae removed, protamine.CPB discontinued, cannulae removed, protamine. Pacing wires, drainage tubes, hemostasis and closure.Pacing wires, drainage tubes, hemostasis and closure.

CABGCABG

OPCABOPCAB

Attempt to maintain normothermiaAttempt to maintain normothermia Median sternotomyMedian sternotomy Conduit harvestingConduit harvesting Heparin. Pacing wires.Heparin. Pacing wires. Maneuvers to maintain hemodynamic stability Maneuvers to maintain hemodynamic stability

(Trendelenburg, table, R pleura,.)(Trendelenburg, table, R pleura,.) Pericardial slingPericardial sling Luxation. Stabilisation. Distal anastomoses with or Luxation. Stabilisation. Distal anastomoses with or

without shunting.without shunting. Proximal anastomoses. Protamine.Proximal anastomoses. Protamine. Chest drains. Hemostasis. Closure.Chest drains. Hemostasis. Closure.

Not discussedNot discussed

IABP and other support devicesIABP and other support devices Emergency surgeryEmergency surgery Redo surgeryRedo surgery Other modalities of bypass grafting: Other modalities of bypass grafting:

MIDCAB, robotic surgery, …MIDCAB, robotic surgery, … Adjunctive surgical treatment: TMLR, Adjunctive surgical treatment: TMLR,

growth factors, cell transplantationgrowth factors, cell transplantation Combined surgeryCombined surgery

ResultsResults

Early mortality can be predicted, using risk Early mortality can be predicted, using risk stratification models (Euroscore, STS)stratification models (Euroscore, STS)

Time-Related Survival, generally:Time-Related Survival, generally: 1 month: 98%1 month: 98% 1 year: 97%1 year: 97% 5 year: 92%5 year: 92% 10 year: 81%10 year: 81% 15 year: 66%15 year: 66%

NB: NB: ± 25% of early and late deaths are not ± 25% of early and late deaths are not related to CAD or CABGrelated to CAD or CABG

Time-Related SurvivalTime-Related Survival

ResultsResults

Freedom from angina: 60% at 10 yearsFreedom from angina: 60% at 10 years Freedom from AMI: 86% at 10 yearsFreedom from AMI: 86% at 10 years Freedom from sudden death: 97% at 10 yearsFreedom from sudden death: 97% at 10 years 80% of patients are working 1 year postop.80% of patients are working 1 year postop. Graft patency: Graft patency:

LIMA (to LAD) LIMA (to LAD) ± 90% at 10 and 20 years. ± 90% at 10 and 20 years. Radial artery ± 80% at 7 yearsRadial artery ± 80% at 7 years Gastro-epiploic artery ± 60% at 10 yearsGastro-epiploic artery ± 60% at 10 years SVG ± 50-60% at 10 years, 80% to LADSVG ± 50-60% at 10 years, 80% to LAD