Coronary Artery Disease

Question 1

Non-classic sx of CAD

Answer 1

• Dyspnea
• Dizziness
• Syncope
• Pulmonary edema

Question 2

Pathophysiology of Coronary artery disease

Answer 2

Question 3

Gold standard dx test for CAD

Answer 3

Coronary angioraphy

Question 4

• 75% reduction in coronary artery cross-sectional area results in _
• 90% reductino in coronary artery cross-sectional area resutls in _

Answer 4

• 50% loss of arterial diamter (anginia with activity)
• 75-80% doss of diamter (angina with rest)

Question 5

Presenting clinical scenarios for CAD

Answer 5

• Chronic, stable angina
• Acute coronary syndrome (ACS)
  
  • ST elevation MI (STEMI)
    
    • myocardial necrosis with elevated biomarks and ST changes on EKG
  • Non-ST elevatin MI (NSTEMI)
    
    • myocardial necrosis with elevated biomarkers without ST changes on EKG
  • Unstable angina

Question 6

Etiology of STEMI

Answer 6

Rupture of atherosclerotic plauqe with acute mural thrombus formation and coronary artery obstruction

Question 7

Etiology of NSTEMI

Answer 7

• Atherosclerotic plaque rupture and thrombosis (MC)
• Coronary spasm (Prinzmetal’s angina)
• Progressive coronary obstruction
• Increased oxygen demand (demand ischemia, tachycardia)
• Decreased oxygen supply (anemia)

Question 8

Answer 8

Question 9

3 primary mechanisms through which CAD results in LV dysfunction

Answer 9

1. MI (irreversible) with loss of myocardium
2. Hybernating myocardium
   
   1. Myocardial dysfunction at rest due to CAD that partially resolves after revascularization
3. Stunned myocardium
   
   1. Transient myocardial dysfunction after reperfusion

Question 10

AHA/ACC Guidelines for Medical Management of CAD

Answer 10

• Smoking cessation
• Hypertension (goal < 140/90, or < 130/80 if DM or CKD)
• Hypercholesterolemia (goal LDL < 100; if TG > 200, then non-HDL < 130)
• Obesity (BMI 18.5-24.9)
• DM (goal HgbA1c < 7%)
• Anticoagulation
  
  • ASA 81 mg (all patients)
  • ASA 81 + Plavix 75 (ACS or PCI)
• ACE-I (EF < 40%)
  
  • ARB if intolerant to ACE-I
• Beta-blocker (all pts with MI, ACS, LV dysfunction)
• Aldosterone inhibitor (large MI in patient with low EF, no renal dysfunction)

Question 11

Summary of SYNTAX Trial

Answer 11

NEJM (2009)

• PCI vs. CABG
• Non-inferiority (LM or 3v CAD)
• Primary results:
  
  • Composite adverse events + cerebrovasc events higher in PCI vs. CABG
    
    • Primarily driven by higher repeat revascularization in PCI
  • Simlar MI and death rates
  • Stroke rates higher in CABG

Question 12

General repeat revascularizaton rates for PCI and CABG

Answer 12

• PCI (30% at 1 year and 55% at 5 years)
• CABG (3-15%)

Question 13

AHA/ACC Guidelines for CABG

Answer 13

• LM disease (>50% stenosis)
• LM equivalent diease (pLAD >70% + pCx stenosis)
• 3v CAD (especially if EF < 50%)
• 2v CAD with EF < 50%
• pLAD + 1-2v CAD
• Disabling angina refractory to medical managment
• Failed PCI
• Anatomy not suitable for PCI
  
  • Total occlusion
  • Circumferential calcification
  • Bifurcation involvment
  • Diffuse or distal lesions
• Concomitant cardiac lesions requiring surgery

Question 14

Tx STEMI

Answer 14

Non-surgical, usually medical, unless ongoing ischemia or cardiogenic shock despite maximal medical therapy

Question 15

Hemodynamic instability during OPCAB often due to:

Answer 15

• RV compression (exposure of lateral LV wall)
• Diastolic dysfunction from excessive downward pressure from coronary stabilizer
• Intraoperative ischemia from native CAD or coronary snaring

Question 16

Results of OPCAB versus On pump-CAB

Answer 16

• Surgical outcomes similar
• OPCAB:
  
  • Less blood loss and tranfusions
  • Less myocardial enzyme release in 24 hrs
  • Less neurocognitive dysfunction
  • Less renal insufficiency
• On-pump CABG
  
  • Higher number of total bypass grafts (more complete revascularization)
  • Easier grafts to posterior (Cx) targets
  • ? better long-term graft patency

Question 17

What are the diagnostic features of an acute ST elevation myocardial infarction (STEMI)?

Answer 17

a) ST elevation (>0.1mV except >0.2mV in V1-3 at the J point in two or more contiguous leads) with peaked T wave;
b) pathological Q waves >0.04sec or >25% of total QRS complex;
c) ischaemic type chest pain lasting >20 minutes.