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Snapshot
  • A 67-year-old door-to-door meat salesman is brought to the emergency department by ambulance after complaining to his coworkers of sudden onset chest tightness and shortness of breath. He has pain in his chest that radiates to his left arm and jaw.  He has a past medical history of type II diabetes mellitus.  He has a 45 pack-year smoking history, takes aspirin and simvastatin, and has a BMI of 37.
Introduction
  • Primary cause of ischemic heart disease is atherosclerotic occlusion of the coronary arteries
    • major risk factors include
      • diabetes mellitus (most important and considered a CAD equivalent)
      • smoking (#1 preventable factor)
      • HTN
      • high cholesterol / Hyperlipidemia (total cholesterol - HDL ratio > 5.0)
      • family history
      • age > 45 men, > 55 women
    • minor risk factors include
      • obesity
      • lack of estrogens
      • homocystinuria
      • cocaine use
      • amphetamine use
Presentation
  • Symptoms
    • range from asymptomatic
      • particularly in older women and diabetics
    • to substernal tightness and/or pain
    • and shortness of breath
    • often diagnosed and characterized as
      • stable angina
        • predictable; presents with consistent amount of exertion
        • patient can achieve relief with rest or nitroglycerin
        • indicative of a stable, flow-limiting plaque
      • unstable angina
        • unpredictable; often presents at period of inactivity
        • defined as any new angina or rapidly worsening stable angina
        • limited improvement with nitroglycerin, and usually recurs soon afterward
        • indicative of a ruptured plaque with subsequent clot-formation in vessel lumen
  • Physical exam
    • in asymptomatic patients is usually normal
    • can demonstrate mitral regurgitation murmur and/or S4 during episodes
    • may also include signs of CHF from prior MI including
      • elevated JVD
      • lower extremity edema
      • crackles
    • and other signs of vascular disease including 
      • bruits
      • ischemic ulcers
      • and diminished pulses
Evaluation
  • Cardiac catheterization for definitive diagnosis   
    •  locate and assess severity of the lesion(s)    
  • CXR
    • to rule out aortic dissection
  • Elevated cardiac biomarkers
    • troponin, CK, and/or CK-MB may be present
  • EKG 
    • shows ST elevation or depression depending on severity of ischemia
    • and Q waves
  • Stress-testing  
    • to evaluate simultaneously with EKG, echo, and radionuclide perfusion studies
    • for patients without a history of prior coronary artery disease, all antianginal medications (beta-blockers, nitrates, calcium channel blockers) should be held for 48 hours before a stress test
    • for pharmacological stress tests using adenosine or regadenoson, use of dipyridamole should be held for 48 hours and intake of caffeine held for 12 hours to minimize false negative findings of ischemia
Differential
  • Myocardial infarction, aortic dissection, GERD, pericarditis, pulmonary embolism, spontaneous pneumothorax, esophageal spasm, and musculoskeletal disorders
Treatment
  • In acute coronary syndrome use 
    • morphine
    • oxygen
    • nitroglycerin
    • aspirin
    • ACEI's
    • may also use β-blockers, GPIIb/IIIa antagonists, angioplasty
  • Drugs that improve post-MI mortality rates include
    • Aspirin
    • β-blockers
    • ACEIs
    • ARBs
    • and HMG-CoA reductase inhibitors
    • NOT calcium channel blockers
Prognosis, Prevention, and Complications
  • Must control diabetes
    • considered a CAD equivalent causing
    • MI to often present atypically in these patients
  • Manage hypertension (<140/90 mmHg)
  • Manage cholesterol levels (<70 mg/dL)
  • Encourage smoking cessation and alcohol obstention
  • MI prevention with
    • Aspirin or clopidogrel (for ASA sensitivities)
  • Angina prevention with
    • β-blockers 
      • to lower HR
      • increase myocardial perfusion time
      • and decrease cardiac work load
    • nitrates + calcium channel blockers in severe or recurring cases
 

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