Transcript CAD - CCRMC Wiki

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
Coronary athero progression
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.
CCTA: Right Coronary Artery
Symptomatic CAD: Influence of CT Calcium Score
(JACC 2007; 50: 1469)
N = 254 (symptomatic)
CAD: >50% stenosis in 1 vessel by cath
Probability (%)
Low
(0-30)
Intermediate High
(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
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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
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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
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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
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Sudden death
ST elevation MI
Non ST elevation MI
Unstable angina
Stable angina
Variant ( vasospastic angina )
Cardiac Sudden Death
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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
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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
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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
• Chest pain where tests are equivocal
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
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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
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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
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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
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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
RX LAD
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)
Men
Women
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
Vulnerable Plaque : hs CRP
(Circulation 2002; 105: 1135)
•hs CRP: most sensitive independent marker of CV risk, including
sudden death (Circulation 2002; 105: 2595; Arch Int Med 2002; 162: 867; TIMI 11A
substudy: JACC 1998; 31: 1460)
•Asymptomatic persons with  hsCRP   coronary atherosclerosis
/ calcification (Framingham Heart Study: Circulation 2002; 106: 1189).
•hsCRP is an independent and stronger predictor of CV events than
LDL-C; best prediction is hsCRP + T-C/HDL-C ratio (WHS study: NEJM
2002; 347: 1557)
•hsCRP is predictor of CV events even when LDL-C levels are below
target values (WHS group: NEJM 2000; 342: 836; CARE study: Circulation 1999; 100:
230)
•Statins  hsCRP (PRINCE study: JAMA 2001; 286: 64; CARE study: Circulation
1999; 100: 230)   CV events (AFCAPS/TEXCAPS study: NEJM 2001; 344: 1959)
Vulnerable Plaque: MDCT Coronary Calcium Score
Coronary calcium: > 130 Hounsfield units
•Calcium is 100% specific for atherosclerosis
•Calcium shows weak correlation with luminal narrowing
•Area of calcium correlated (r = 0.9) with area of plaque
•Calcium area approximately 20% of associated plaque area
•“Soft plaque” → no detectable calcium
Symptomatic CAD: Influence of CT Calcium Score
(JACC 2007; 50: 1469)
N = 254 (symptomatic)
CAD: >50% stenosis in 1 vessel by cath
Probability (%)
Low
Intermediate High
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
Vulnerable Myocardium: No Structural Disease
(JACC 2004; 43: 1137)
Long QT syndromes (LQTS)
(QTc > 440 msecs in males, > 460 msecs in females)
Brugada syndrome
Pre-excitation (WPW syndrome)
-----------------------------------------------------------Short-coupled torsades
Drug-induced torsades
Idiopathic VT
Commotio cordis
Selection of Stress Test
Patient can Exercise:
•Low incidence of false positive:
Exercise EKG
•↑ False positives with exercise EKG:
Exercise Echo; Exercise thallium-sestamibi
Patient cannot Exercise / Uninterpretable exercise EKG:
Pharmacologic stress test:
Dobutamine echo
Adenosine thallium-sestamibi
CAD: Risk Assessment (Prognosis)
Virtually all patient management decisions must driven by
the clinician's assessment of the patient's prognosis.
It is risk assessment that should indicate the need for testing
and/or therapy
Failure to assess risk leads to inappropriate and expensive
testing in low risk patients, and less aggressive management
in those at very high risk.