Rosen & Barkin's 5-Minute Emergency Medicine Consult (128 page)

• CXR:
  
  • Usually normal
    
  • May show cardiomegaly
    
  • May show pulmonary edema
    
  • May identify other etiologies of chest pain, such as pneumonia or widened mediastinum of aortic dissection.
    
• Rest echocardiography:
  
  • May identify ACS or AMI based on wall motion abnormalities; also can detect pump failure and valvular abnormalities.
    
  • Rest echo has a sensitivity of 70% and specificity of 87% for ACS.
    
  • Rest echo has a sensitivity of 93% and specificity of 66% for AMI.
    
• Technetium 99m sestamibi:
  
  • Radioactive IV dye taken up by myocardium, and detected by single photon emission CT (SPECT) imaging. (Also known as myocardial perfusion imaging.)
    
  • Can be imaged at rest to detect low- or no-flow areas of myocardium; can also be imaged after exercise or pharmacologic stress.
    
  • Per 2009 AHA/ACC guidelines, reserve for intermediate- to high-risk patients.
    
  • Has a sensitivity of 81% and specificity of 73% for ACS.
    
  • Has a sensitivity of 92% and specificity of 67% for AMI.
    
• CT coronary angiography (CTCA):
  
  • Imaging to evaluate degree of coronary artery stenosis and calcium deposits
    
  • Negative predictive value between 97% and 100%, accuracy comparable to stress testing
    
  • Recent NEJM article suggests CTCA decreases ED length of stay but leads to further downstream testing, radiation exposure, and no decrease in cost of care.
    
• Exercise stress testing (ETT):
  
  • May help establish diagnosis of angina, provide prognostic information.
    
  • 1-mm depression of the ST-segment in 3 consecutive beats and 2 consecutive leads is characteristic of cardiac ischemia.
    
  • Early positive (within 3 min) stress tests are worrisome for unstable angina.
    
  • 6 min of exercise using a standard Bruce protocol suggests an excellent prognosis.
    
  • Exercise stress testing with EKG alone has a sensitivity of 68% and specificity of 77%.
    
  • Exercise stress testing with echo has a sensitivity of 85% and specificity of 77%.
    
  • Exercise stress testing with technetium
    ^99m
    sestamibi has a sensitivity of 87% and specificity of 64%.
    
• Cardiac catheterization:
  
  • Considered the gold standard for evaluating coronary arteries.
    
  • A history of a recent negative catheterization does not fully exclude AMI, i.e., in cases of vasospasm or cocaine use.
    

EKG, cardiac enzymes, echo, stress testing

See ACS chapters.

TREATMENT

• Cardiac monitoring
  
• Out-of-hospital EKG:
  
  • Alone has a sensitivity of 76% and specificity of 88% for ACS.
    
  • Alone has a sensitivity of 68% and specificity of 97% for AMI.
    

• Cardiac monitoring
  
• Oxygen saturation
  

• See “Acute Coronary Syndrome: Stable Angina”; “Acute Coronary Syndrome: Unstable Angina”; and “Acute Coronary Syndrome: MI” for more detail.
  
• Guidelines for cardiac testing
  
• History suggestive of ACS:
  
  • Obtain ECG and 1st troponin (or other cardiac biomarkers).
    
• ECG or 1st troponin abnormal:
  
  • Admit; consider cardiology consult.
    
• Ongoing chest pain or pressure:
  
  • Obtain sestamibi or echo.
    
  • Consider serial EKGs
    
• Sestamibi, serial EKG or echo abnormal:
  
  • Admit or cardiology consult.
    
• Second troponin (or other cardiac biomarkers) abnormal:
  
  • Admit; consider cardiology consult.
    
• Ancillary testing:
  
  • For low- to moderate-risk patients: standard exercise testing (ETT).
    
    • If low-risk patient with good follow-up, ACC/AHA guidelines allow for outpatient stress testing within 72 hr.
      
    • Per 2007 AHA/ACC guidelines CTCA “reasonable alternative” to stress testing.
      
  • For abnormal or uninterpretable EKG: Stress echo or sestamibi.
    
  • For patient unable to exert self: Pharmacologic ETT (i.e., dobutamine stress or dipyridamole sestamibi).
    
  • Ancillary testing abnormal:
    
    • Cardiology consult or admit.
      

Patient should not be started on new antianginal medication before stress testing in the ED.

FOLLOW-UP

• History suggestive of cardiac etiology for chest pain and ED observation for serial testing unavailable
  
• Abnormal or changed EKG and ED observation unavailable
  
• Positive cardiac biomarkers
  
• Positive rest imaging
  
• If the diagnosis is unclear, admission to the hospital or an ED observation unit may be useful for serial cardiac biomarkers, EKGs, and further ancillary testing.
  
• Early positive stress test:
  
  • If the patient has a positive stress test, the decision for admission should be made in consultation with the primary care physician or cardiologist.
    

Patients who meet the following criteria are safe to discharge:

• History not suggestive of cardiac etiology for chest pain
  
• Normal ECG
  
• Normal cardiac testing
  

• Abnormal stress test will require close follow-up with cardiology or PCP.
  
• Undifferentiated CP should have ED stress testing unless clear follow-up is available.
  

• Normal EKG or enzymes do not rule out CAD.
  
• Repeat EKG or additional leads improve sensitivity in detecting AMI.
  
• Most ED patients with undifferentiated chest pain will need some form of additional testing.
  

• Cardiac Radionuclide Imaging Writing Group. Criteria for Cardiac Radionuclide Imaging. ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 Appropriate Use Criteria for Cardiac Radionuclide Imaging. Joint guideline of ACC/AHA.
  
• 2013 ACCF/AHA Guideline for Management of ST Elevation Myocardial Infarction.
  J Am Coll Cardiol.
  2012.
  
• Hoffman U, Truong QA, Schoenfeld DA, et al. Coronary CT angiography versus standard evaluation in acute chest pain.
  N Engl J Med
  . 2012; 367:299–308.
  
• Yiadom MY. Acute coronary syndrome clinical presentations and diagnostic approaches in the emergency department.
  Emerg Med Clin North Am
  . 2011;29:689–697.
  

CODES

• 89.59 Other nonoperative cardiac and vascular measurements
  
• 411.1 Intermediate coronary syndrome
  
• 413.9 Other and unspecified angina pectoris
  

BASICS

• Cardiac transplant recipients are a unique population with increased risk for cardiac ischemia, heart failure, as well as general risks as an immunocompromised host.
  
• 1,900–2,300 cardiac transplants per yr in US
  
• 1-yr survival 85–90%; 5-yr survival ∼75%
  
• Typical immunosuppressive therapy to control rejection is a “triple-drug” regimen often including steroids.
  
• Frequent biopsies are used initially to evaluate rejection; echocardiography often used in children.
  
• Complications occur most commonly in the 1st 6 wk after cardiac transplantation
  

• The proportion of elderly patients on the transplant list, and receiving transplants are increasing.
  
• Due to changes in immune system with age, elderly transplant recipients are at increased risk of life-threatening infections, and acute rejection.
  

• Pregnancy after cardiac transplant is becoming more common. Between 1988 and 2010, 63 women received either heart or heart–lung transplants. They have reported 108 pregnancies, all progressing to live births.
  
• Most common complications include hypertension, pre-eclampsia, and rejection.
  
• Physiologic changes that occur with pregnancy do not relate to increased rate of heart failure in transplant patients.
  
• Special attention should be paid to these patients regarding rejection and infection given their immunosuppression.
  

• Rejection
  
  • Hyperacute rejection
    
    • Occurs within minutes of transplantation
      
    • Rare, due to ABO or other graft/host major incompatibility
      
    • Aggressive and immediately fatal to graft
      
  • Acute rejection
    
    • Lymphocyte infiltration and myocyte destruction
      
    • Most common in 1st 6 wk
      
    • May occur at any time
      
    • 75% prevalence
      
  • Chronic rejection
    
    • Fibrosis and graft vascular disease
      
    • Long-term complication
      
    • Incompletely understood etiology
      
    • No effective therapy
      
• Cardiac allograft vasculopathy
  
  • Analogous to accelerated coronary artery disease in native hearts
    
  • Limits long-term survival, leading cause of mortality after 1 yr
    
• Immune-mediated atherosclerosis
  
  • Form of chronic rejection
    
• Infections
  
  • 1st mo
    
    • Bacterial infections are the most common cause of mortality during this high-risk time period
      
    • Pneumonia (Pseudomonas, Legionella, other gram-negative organisms)
      
    • Mediastinitis
      
    • Wound infection
      
    • UTI
      
  • 1st yr
    
    • Opportunistic and conventional infections
      
    • Cytomegalovirus (CMV)
      
    • Herpes simplex virus (HSV)
      
    • Legionella
      
    • Fungal infections
      
    • Pneumocystis carinii
      
• Medication toxicity
  
  • Cyclosporine, Neoral (2nd-generation cyclosporine), tacrolimus:
    
    • Nephrotoxicity (30% incidence)
      
    • Hepatotoxicity
      
    • Neurotoxicity
      
    • Hyperlipidemia, diabetogenic
      
  • Azathioprine, mycophenolate mofetil:
    
    • Bone marrow suppression
      
    • Leukopenia
      
  • Sirolimus:
    
    • Hyperlipidemia
      
    • Wound healing
      
  • Steroids
    
    • Osteoporosis
      
    • Cushing disease
      
• Neoplasms
  
  • Secondary to immunosuppression
    
  • 10–100 times more common vs. general population
    
  • Skin and lip cancer
    
  • Lymphomas
    
  • Kaposi's sarcoma
    
  • Solid organ neoplasms