Surgery of Coronary Artery Disease

Ischemic Heart Disease IHD – imbalance between myocardial oxygen demand and supply: Coronary Artery Disease Printzmetal Angina Syndrome X

Coronary Artery Disease (CAD) Deficiency in blood supply to myocardium caused by stenotic atheromatous lesions in major branches of coronary arteries

Clinical Forms of CAD Stable Angina Unstable Angina Acute Coronary Syndrome Myocardial Infarction Ischemic Myocardiopathy (Left Ventricular Remodeling, Mitral Regurgitation)

Prevalence of CAD About 50% of total mortality in Europe and North America is due to cardiovascular diseases 100.000 of Acute Myocardial Infarctions in Poland each year The older population the more prevalent CAD

Complex Etiology of Atheromatosis Genetic (family history) Metabolic (hyperlipidemia, diabetes) Life Style (obesity, smoking, lack of exercise) Infectious and Inflammatory?

Risk Factors of CAD Sex - male Age - older Family History Arterial Hypertension Hyperlipidemia Smoking Obesity

Symptoms of CAD (1) Angina – retrosternal chest pain, usually related to the exercise Canadian Cardiovascular Society (CCS) Classification of Angina: I class – only in extreme exercise II class – in moderate exercise III class – in every exercise IV class – also in rest

Symptoms of CAD (2) Dyspnea (in Ischemic Myocardiopathy or Mitral Regurgitation) New York Heart Association (NYHA) classification of dyspnea (I-IV class) When NYHA class higher than CCS class – poor prognosis

Pathology of CAD (1)

Pathology of CAD (2)

Pathophysiology of CAD Consequences of Coronary Artery Stenosis: Up to 50% - asymptomatic About 75% - exercise angina More than 90% - rest angina 100% - AMI

Diagnostics of CAD

Evidence taken from Exercise ECG Clinically positive (angina) ECG positive (ST segment abnormalities) localization: anterior, lateral, posterior Exercise tolerance (in METs*) * MET – metabolic equivalent – rest oxygen demand = 30 ml/kg/min

Evidence taken from Echocardiography Global systolic function of left ventricle – left ventricular ejection fraction (LVEF): Good – LVEF>50% Moderately impaired –LVEF 30-50% Poor –LVEF<30% Regional systolic abnormalities (hypokinesis, akinesis, dyskinesis) Mitral Regurgitation

Indications for Coronary Angiography Typical Angina (even with negative ECG exercise test) Positive ECG exercise test Unstable Angina / Acute coronary syndrome (primary rescue PCI) After Myocardial Infarction especially when angina persists

Technique of Coronary Angiography Selective coronary artery catheterization via femoral or radial artery Administration of iodine contrast X-ray motion picture

Evidence taken from Coronary Angiography Presence of lesions in coronary arteries Degree of stenosis (0-100%) Localization of lesions (proximal or distal) Type of lesions (A, B or C)

What is a significant stenosis of coronary artery? Left main stem (LMS) stenosis of 50% or more Other vessels stenosis of 75% or more

Clinical Value of Coronary Angiography in Decision Making

Invasive Cardiology or Surgery Invasive Cardiology or Surgery? The most important disadvantage of PCI is still high rate of re-stenosis, reaching 30% per year (10% using DES)

Anatomy of Coronary Arteries

Anatomy of Left Coronary Artery

Anatomy of Right Coronary Artery

The Milestones of Coronary Surgery 1959 Sonnes Coronary angiography 1964 Kolesov Graft:LITA-LAD (no CPB, no Angiography) 1967 Favaloro CABG 1991 Benetti OPCAB

Idea of Surgical Treatment of CAD Revascularization of the heart via by-passing significantly narrowed coronary arteries to enhance blood supply to ischemic regions of myocardium

The Goals of Surgery in CAD To prolong a lifetime To improve a quality of living To prevent myocardial infarction and its complications

Surgical Revascularization Procedures Coronary Artery By-Pass Grafting (CABG) - CLASSIC Off-Pump Coronary Artery By-Pass (OPCAB) – NO CPB Minimally Invasive Coronary Artery By-Pass (MID-CAB) – NO STERNOTOMY Transmural Laser Revascularization (TMLR) - ALTERNATIVE

CABG – The Classic Coronary Operation Since 1967 when Favaloro from Cleveland Clinic in USA performed the first CABG it has become one of the most popular surgical procedure in the world

CABG or OPCAB? The biggest advantage of OPCAB is avoidance of complications related to CPB e.g. SIRS and slightly lower costs However, OPCAB provides less completeness of revascularization and worse precision of anastomosis (moving operating area) Classic indication for OPCAB is isolated stenosis of LAD not suitable for PCI e.g. amputation

OPCAB

Cardio-Pulmonary Bypass (CPB)

Cardio-Pulmonary By-Pass (CPB) Extracorporeal circulation (ECC) Requires full heparinization of the patient Main elements: System of cannules, tubes and filters Oxygenator Pumps (arterial and suction) Side effects Blood cells damage Systemic Inflammatory Response Syndrome (SIRS)

Indications for CABG Left main stem stenosis > 50% Equivalent of LMS stenosis (proximal stenosis of LAD and Cx > 75%) Three-vessels disease (stenoses of RCA, LAD and Cx or their branches >75%) Proximal LAD stenosis >75% with one- or two-vessels disease, with excessive part of myocardium in jeopardy, especially in patients with poor LV function and/or in diabetics (not suitable for PCI, method of choice if isolated– OPCAB)

Counter-indications for CABG Acute myocardial infarction (2 weeks) Use of antiplatelet drugs like ticlopidine or clopidogrel (2 weeks or platelet concentrate – if emergency) Lack of graftable distal vessels (diameter of at least 1,5mm) – consider TMLR

Scheduled or emergency CABG?

Patient’s Preparation to Scheduled CABG Red cells concentrate (autotransfusion, family donations) Coagulometry Cessation of antiplatelet drugs (2 weeks before surgery) Optimal medical treatment (beta-blockers, statins, control of glycemia in diabetics) Co-morbidities (carotid doppler, gastroscopy)

Predictors of Outcomes after CABG Age > 60 years Female sex Poor LV function Re-do operation Emergency Obesity Co-morbidities Renal failure Chronic Obturatory Pulmonary Disease Stroke Generalized atherosclerosis

CABG-Technique Medial Sternotomy Use of CPB Saphenous by-pass grafts (SBG) or arterial grafts

Material for Grafts in CABG Saphenous vein (SBG) Left internal thoracic artery (LITA) Right internal thoracic artery (RITA) Radial artery (RA) Gastroepiploic artery

Venous or arterial grafts? Arterial grafts are generally better than venous – e.g. LITA patency rate after 20 years is 90% whereas 50% of SBGs is occluded after 10 years. GOLDEN STANDARD: LITA to LAD! Totally arterial revascularization is especially indicated in young patients and in those with bilateral crural varicosity

CABG

Venous grafts

Venous sequential graft

Harvested LITA

Graft: LITA to LAD

Harvesting and anastomosing of Radial Artery

Outcomes of CABG Mortality rate 1-5% - depends mostly of patients’ profile (see predictors of outcomes ) Common postop. complications: Excessive bleeding, heart tamponade Perioperative myocardial infarction - low cardiac output Stroke or psycho-organic syndromes Acute renal failure Hemothorax, pneumothorax Sternal dehiscence, mediastinitis

Typical uncomplicated course after CABG ICU 1-2 days: Artificial ventilation <12 hours Chest tubes – 2 days Hospital stay – about 1 week Antibiotics – 4 days Rehabilitation 2-3 weeks Most of the patients returns to normal activity in few months

Standard Medication after CABG „A B S” ASA 150-300 mg daily Beta-Blockers Statins

Secondary Prevention after CABG Lipids control Glucose control Weight control Arterial pressure control Smoking cessation Moderate exercise