Spotlight Case January 2004

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Spotlight Case January 2004

• Crushing Chest Pain A Missed Opportunity

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Source and Credits

• This presentation is based on the Jan. 2004 AHRQ
  WebMM Spotlight Case
• See the full article at http//webmm.ahrq.gov
• CME credit is available through the Web site
• Commentary by Mark Graber, MD, State University
  of New York at Stony Brook
• Editor, AHRQ WebMM Robert Wachter, MD
• Spotlight Editor Tracy Minichiello, MD
• Managing Editor Erin Hartman, MS

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Objectives

• At the conclusion of this educational activity,
  participants should be able to
• Appreciate the challenges of diagnosing aortic
  dissection
• Describe the Bayesian approach to diagnosis
• Understand the benefits and limitations of
  heuristic thinking
• List the cardinal dimensions of clinical
  decision-making

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Case Crushing Chest Pain

• A 62-year-old female presented with 12 hours of
  crushing chest pain. Her blood pressure was
  140/90, heart rate 110, and respiratory rate 16.
  An EKG revealed left ventricular hypertrophy with
  strain. Review of the chest x-ray in the
  emergency department (ED) revealed no
  abnormalities. She was treated for an acute
  coronary syndrome (ACS) with heparin, aspirin,
  morphine, and a nitroglycerin drip. Cardiac
  enzymes were drawn.

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Case (cont.) Crushing Chest Pain

• The patient was admitted to the cardiac care
  unit. Seven hours after admission, the patient
  became hypotensive, with a systolic blood
  pressure in the 80s and a heart rate in the 120s.
  A repeat EKG revealed no significant changes.
  Right-sided leads showed no evidence of right
  ventricular infarct. The first set of cardiac
  enzymes was equivocal, and a CPK-MB was minimally
  elevated.

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Chest Pain in the Emergency Dept.

• Chest pain is a common complaint in the ED
• Correct and timely diagnosis is critical and
  linked to morbidity and mortality in many
  diagnoses
• Acute coronary syndrome
• Pulmonary embolism
• Aortic dissection

.
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Diagnosis of Chest Pain in the ED
von Kodolitsch Y, et al. Arch Intern Med.
20001602977-82.
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Three Different Approaches to Medical
Decision-Making

• Use of heuristics
• Bayesian approach
• Application of algorithms

Elstein AS. Acad Med. 199974791-4.
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Examples of Medical Decision-Making Using
Heuristics

• AvailabilityDiagnosis springs to mind because
  clinician has seen such patients before
• RepresentativenessMental match between patients
  symptoms and characteristic symptoms of disease
  stored in clinicians memory

Elstein AS. Acad Med. 199974791-4.
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Benefits and Risks of Using Heuristics

• AdvantageCan reach correct diagnosis rapidly
• DisadvantageCan lead to diagnostic error when
  correct diagnosis not considered

Elstein AS. Acad Med. 199974791-4.
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This Case Approached Using Heuristics

• Clinician knows
• Acute Coronary Syndrome is the most common cause
  of chest pain in the emergency room
• Clinician thinks
• Diagnosis must be ACS

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Medical Decision-Making Using Bayesian Approach

• List all diagnostic possibilities
• Determine likelihood of each
• Gather pertinent clinical data
• Adjust initial probabilities based on clinical
  data using Bayesian calculations

Sox HC Jr, et al. Medical decision making.1988.
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Is this ACS? Bayesian Approach
Nomogram
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Medical Decision-Making Using Bayesian Approach

• After adjusting pretest probability by clinical
  data available in this case (lack of ECG
  findings, lack of rales, hypotension, etc.), the
  overall likelihood of ACS is less than 17
• CONSIDER ALTERNATIVE DIAGNOSIS!

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Medical Decision-Making Using Algorithmic Approach

• Use of algorithms can simulate expert thinking
• Multiple decision models available
• Algorithms improve sensitivity and specificity of
  diagnosing cardiac ischemia when compared with
  clinical judgment

Panju AA, et al. JAMA. 19982801256-63. Goldman
L, et al. N Engl J Med. 1988318797-803. Pozen
MW, et al. N Engl J Med. 19843101273-8.
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Medical Decision-Making Using Algorithmic Approach

• Use of a formula based on 7 clinical variables to
  predict cardiac ischemia results in a likelihood
  of ACS of 7
• Use of a derived prediction rule using 4 clinical
  variables (hx MI, diaphoresis, ST elevation, q
  waves) results in a likelihood of 2 of ACS in
  this patient
• CONSIDER ALTERNATIVE DIAGNOSIS!

Pozen MW, et al. N Engl J Med. 19843101273-8.
Tierney WM, et al. Crit Care Med.
198513526-31.
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Case (cont.) Crushing Chest Pain

• The team re-reviewed the chest x-ray and
  discovered an abnormality in the aorta a 1-cm
  separation between the intimal calcification and
  the adventitial outline of the descending aorta
  (the calcium sign), consistent with aortic
  dissection.

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Chest X-ray with Calcium Sign (arrow)
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Aortic Dissection

• Mortality rates approach 1 per hour
• Diagnosis is missed in 25-50 of patients
• Survival exceeds 90 with prompt diagnosis and
  management

Spittell PC, et al. Mayo Clin Proc.
199368642-51. Klompas M. JAMA.
20022872262-72. Nienaber CA, et al. N Engl J
Med. 19933281-9.
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Aortic Dissection

• Classic presentation includes acute-onset, severe
  chest/back pain described as tearing or
  ripping
• Atypical presentations are common
• 15 of patients report NO pain
• Supportive findings include pulse deficit, new
  aortic regurgitation, tamponade, and focal
  neurological deficits
• Majority of patients have no specific physical
  findings

Spittell PC, et al. Mayo Clin Proc.
199368642-51. Hagan PG, et al. JAMA.
2000283897-903.
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Aortic Dissection Physical Exam Findings
Klompas M. JAMA. 20022872262-72.
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Aortic Dissection

• 90 of patients with aortic dissection have an
  abnormal CXR
• Abnormal aortic contour and widened mediastinum
  are the most common findings
• A NORMAL CXR DOES NOT RULE OUT AORTIC DISSECTION!

Spittell PC, et al. Mayo Clin Proc.
199368642-51. Hagan PG, et al. JAMA.
2000283897-903.
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Aortic Dissection CXR Findings
Klompas M. JAMA. 20022872262-72.
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Case (cont.) Crushing Chest Pain

• A transesophageal echocardiogram revealed an
  ascending aortic dissection. Anticoagulation
  therapy was discontinued, beta-blocker therapy
  was initiated, and cardiothoracic surgery was
  called. The patient was transported to the
  operating room. Upon arrival in the operating
  room, the patient became progressively
  hypotensive, coded, and died. Post-mortem autopsy
  revealed hemorrhage into the pericardium.

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Transesophageal Echocardiography of Aortic
Dissection
Video
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What Went Wrong?

• The patients death may be result of errors in
  each of the cardinal dimensions of clinical
  decision-making
• Data gathering
• Hypothesis generation/synthesis
• Verification

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Errors in Clinical Decision-Making

• Data gathering
• Staff not trained to recognize the calcium sign
• Synthesis
• Diagnosis of ACS assigned despite low likelihood
• An alternative diagnosis was not initially
  entertained
• Verification
• Premature closure CCU team accepted diagnosis of
  ACS without re-examining the facts
• Framing Team biased by how case was presented
• Anchoring Team fixated on an early diagnosis

Rosman HS, et al. Chest. 1998114793-5. Elstein
AS. In Clinical reasoning in the health
professions. 199549-59. Kassirer JP, Kopelman
RI. Am J Med. 198986433-41. Graber M, et al.
Acad Med. 200277981-92.
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Avoiding Errors in Clinical Decision-Making

• Consider diseases you cannot afford to miss
• Supplement diagnostic skills using a bayesian
  approach or established algorithms
• Consider tests that will help rule in an
  alternative diagnosis rather than pursue a test
  for a diagnosis already in doubt
• Be aware of common cognitive biasesavoid
  premature closure by re-examining the facts
• Ask yourself, What else could this be?

Rosman HS, et al. Chest. 1998114793-5. Elstein
AS. In Clinical reasoning in the health
professions. 199549-59. Kassirer JP, Kopelman
RI. Am J Med. 198986433-41. Graber M, et al.
Paper presented October 20, 2002 Baltimore, MD.