Coronary Artery Disease • 1.1 million MIs in U.S. annually • 500,000 deaths due to acute MI • Major cause of sudden death not associated with acute MI ( chronic coronary artery disease ). • Major cause of CHF • Acute and chronic anginal syndromes
Stable vs unstable angina • Unstable plaque, Large lipid core,thin fibrous cap and lg amount of inflammatory cells. • Stable plaque, Small lipid core,thick fibrous cap and sparse inflammatory cells.
Symptomatic CAD: Influence of CT Calcium Score(JACC 2007; 50: 1469) • N = 254 (symptomatic) • CAD: >50% stenosis in 1 vessel by cath • Probability (%)LowIntermediateHigh(0-30) (31-70) (>71) • Pretest 13 53 87 • CT Calcium positive 68 * 88 * 96 • CT calcium is useful in symptomatic patients with low/ intermediate pretest probability • CT calcium is not useful in symptomatic high risk patients
CAD: Inflammatory Plaque(NEJM 2000; 342: 101) • Large, eccentric lipid-rich pool > 40% volume • Foam cell infiltration • Thin fibrous cap < 1 m • Local inflammatory environment • macrophages, T cells, neutrophils • smooth muscle cells • enzymes, cytokines metalloproteinases • Neovascularization → intra-plaque hemorrhage
Indications for cardiac catheterization • Selected cases of acute ST elevation MIs • Post MI ischemia • Unstable angina • Selected cases of non ST elev. MI • Chronic angina with strong pos stress test • Patients undergoing valve surgery who have coronary risk factors • ? All MI patients ( open vessel theory ) • Cardiogenic shock.
Coronary arteries • Left main coronary artery • Left anterior descending • Circumflex • Right coronary artery
Branched of coronary arteries • L main : LAD and Circumflex • LAD : septal perforators and diagonals branches • Circumflex : obtuse marginals,posterolateral and atrioventricular • RCA : SA nodal, AV nodal, conus, RV, posterolateral and posterior descending
RX L Main Coronary artery • Degree of stenosis may be difficult to grade • Occlusion causes massive MI • Stenosis-markedly positive stress test • Usual RX is CABG • In special circumstances may be stented.
RX LAD • Major stenosis of LAD usually gives strong positive stress test. • Occlusion of LAD causes a large MI with major decrease in EF • Stenting of high grade proximal stenosis of LAD usually yields excellent results • Stenting of LAD with a large diagonal branch off the lesion may be problematic.
RX Circumflex • CX stenosis often with few ECG findings although classically should show in AVL and V6. • When CX is non dominent MI causes only minor decrease in EF • CX marginal branches are targets for CABG
RX RCA disease • Usually dominant ( main supply to inferior and posterior LV ). PDA usually is a branch of RCA • Occlusion of proximal RCA usually results in a lessor decrease in EF and lower mortality than LAD block • Brady arrhythmias and temporary heart block is common. • RV infarction is uncommon but has a high morbidity and mortality
Presentations of CAD • Sudden death • ST elevation MI • Non ST elevation MI • Unstable angina • Stable angina • Variant ( vasospastic angina )
Cardiac Sudden Death • Ventricular fibrillation • Electro-mechanical dissociation • Asystole • Etiologies : Acute MI, Old MI with EF less than 30 %, Cardiac myopathies from various diseases and various etiolgies with NL LV function ( Brugada,Long QT,idiopathic,IHSS etc.).
Courage Trial • Randomized 2287 pts with chronic stable angina to optimal medical RX vs optimal medical RX plus bare metal stenting. • Patients excluded were UA, strong pos stress test,50% or greater L Main disease,class 4 angina or EF less than 30%.
Courage Trial • No change in outcomes ( death or MI ) but less angina in stent gp at 1 and 3 years but not at 5 years. • 33% of pts in Med RX alone limb eventually needed intervention.
Recommendations based on Courage trial • Pts with symptomatic or asymptomatic stable CAD should undergo assessment of LV fx and risk stratification with ischemia testing. • Stable pts with good LV fx and low risk stress test can be managed medically without cath.
Recommendations from Courage trial • Pts with impaired LV Fx or high risk features on ischemia testing should be cathed. • If angina not well controlled, cath. • 1 or 2 vessel disease with good LV fx should be stented • L main, 3 vessel disease or 2 vessel disease (with LAD): CABG or in selected cases stents.
Outcomes after thrombolytic RX • LAD occlusion: 4-5 lives saved/ 100 pts treated • New LBBB: 6-7 lived saved/ 100 pts treated • RCA or Circumflex occlusion ( Inferior MI,uncomplicated: 1 life saved/ 100 pts treated • Best outcomes occur when pts treated within 4 hours of symptom onset
RX Stable angina • Aspirin • Statin • Beta blocker • All patients after stent or those with ASA intolerance - Clopidogrel • ACE ( Ramipril preferred ) for high risk patients ie diabetes,prior MI,HTN etc. )
RX Unstable angina • Nitrates • Low molecular heparin • Beta blockers to HR about 60 • ASA,preferably non coated • Clopidogrel • 2b3a platelet inhibitor • Statin • ACE for BP control • Cardiology consult quickly to consider cath
Routine Stress testing in Asymptomatic Diabetics(DIAD trial: Diabetes Care 2004; 27: 1954) • N = 1123 (asymptomatic DM, age 50-75 years) MPI + Rx vs Usual Rx for 5 years • Positive MPI: 22% • Moderate- large perfusion defects: 40% • Other risk factors / inflammation biomarkers not predictive of positive MPI except autonomic dysfunction • Using ADA guidelines would have failed to predict 41% of patients with silent ischemia
Post MI Care ( ST elevation ) • Ischemia testing when pt stable ( usually 3-5 days • Pos stress– cardiac cath • Neg stress usually not cathed • All patients instructed about life style changes ( cigs,diet,exercise etc. ) • Meds usually asa,beta blocker,ace and a statin.
Ischemia Tests • Treadmill stress test • Treadmill stress test with Echocardiogram • Treadmill stress test with Thallium • Adenosine or Persantine nucleotide test without exercise ( Sestamibi ) • Dobutamine Echo test without exercise
Contraindications to Stress Testing • MI in past 48 hours • Unstable angina, ongoing • Poorly controlled CHF or arrhythmias • Acute Aortic dissection or PE • Myocarditis • Major associated conditions ie pneumonia,severe anemia,acute renal failure
Relative contraindications to Stress Testing • Severe Aortic Stenosis • SBP >200 or diastolic > 110 • Known L main CAD • Significant arrhythmias • HOCM • Major electrolyte imbalance
Stress Echocardiography • Higher specificity • Versatility: more extensive evaluation of cardiac anatomy and function • Greater convenience, efficacy and availability • Lower cost
Stress Perfusion imaging • Higher technical success rate • Higher sensativity, particularly with 1 vessel disease • Better accuracy when multiple rest-LV wall motion abnormalities are present • Better when good technical Echo can not be obtained • More extensive published data available
Dobutamine Echo • Causes ischemia by increasing O2 demand • Must have a good technical Echo • Used in pts who can not exercise • A positive test is a new regional wall motion abnormality • Usually not helpful with myopathic LV • Don’t use in UA or recent V tach.
Setup for intervention or CABG • Severe ( > 75-80% ) proximal stenosis with the distal vessel being 2.5 mm or larger and free of major disease. • If the distal vessel is very small or has major diffuse disease an intervention or CABG will usually not be successful
Etiologies of ischemia other than Atherosclerosis • Congenital coronary artery anomalies • Cocaine • Prinzmetal’s varient angina • Aortic stenosis or HOCM • Coronary arteritis • Coronary artery ectasia • Bridging coronary arteries ? • Syndrome X • Coronary thrombus
CAD: Screening Asymptomatic Patients • (Ann Int Med 2004; 141: 57) • “ACP/AHA recommends against screening asymptomatic outpatients for CAD” • CAD: Lifetime Risk • (Framingham Heart Study. Circulation 2006; 113: 791; Lancet 1999; 353: 89) • Asymptomatic population between 40-90 years • At age 40 years, lifetime risk is: • Male: 49% • Female: 32% • Aggressive identification and management of asymptomatic patients at risk recommended
Classification of CAD in all Patients • Established CAD • MI, cath-proven CAD, PCI, CABG • CAD equivalent • DM, Cr Cl < 60 ml/min, CVA/carotid IMT > 1.1 mm, PVD, Atherosclerotic aortic aneurysm • Chronic coronary syndrome (CCS) • Chronic stable angina, silent ischemia, Syndrome X • Acute coronary syndrome (ACS) • NSTE-ACS, STE-ACS • Risk for CAD
Vulnerable Patient: Risk Effects(Circulation 2004; 109: 2613) • Cigarette smoking and DM are strongest risk factors • Most common dyslipidemia: (↑TG + ↓HDL-C) • Strongest lipid factor: T-C/HDL-C ratio (JAMA 2001;285: 2481) • At age 40 years (Framingham Heart Study): • Reduced life expectancy (years)MenWomen • Obesity 5.8 7.1 • Smoking 8.66 7.59 • HTN 5.1 4.9 • Sedentary lifestyle 1.3-3.7 1.5-3.5