Coronary Artery Disease

Question 1

Non-classic sx of CAD

Answer 1

• Dyspnea
• Dizziness
• Syncope
• Pulmonary edema

Question 2

Gold standard dx test for CAD

Answer 2

Coronary angioraphy

Question 3

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

Answer 3

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

Question 4

Presenting clinical scenarios for CAD

Answer 4

• 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 5

Etiology of STEMI

Answer 5

Rupture of atherosclerotic plauqe with acute mural thrombus formation and CA obstruction

Question 6

Etiology of NSTEMI

Answer 6

• 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 7

3 primary mechanisms through which CAD results in LV dysfunction

Answer 7

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 8

AHA/ACC Guidelines for Medical Management of CAD

Answer 8

• 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 9

Summary of SYNTAX Trial

Answer 9

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 10

General repeat revascularizaton rates for PCI and CABG

Answer 10

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

Question 11

AHA/ACC Guidelines for CABG

Answer 11

• 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 12

Tx STEMI

Answer 12

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

Question 13

Hemodynamic instability during OPCAB often due to:

Answer 13

• 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 14

Results of OPCAB versus On pump-CAB

Answer 14

• 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