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Difficulty: HardDiagnostic Workup and Test Sequencing

A 67-year-old woman is evaluated in the cardiology clinic for a three-month history of episodic chest heaviness. She reports that the discomfort occurs when she performs upper body exertion, such as vacuuming or carrying groceries, and resolves completely after approximately five minutes of rest. Her medical history is significant for type 2 diabetes mellitus, hypertension, hyperlipidemia, advanced bilateral knee osteoarthritis, and severe persistent asthma. She relies on a motorized scooter for mobility due to debilitating joint pain. Her respiratory regimen includes a daily high-dose fluticasone-salmeterol inhaler and oral montelukast, but she still requires albuterol rescue therapy three to four times a week. Vital signs include a blood pressure of 146/88146/88 mm Hg and a heart rate of 7676/min. Physical examination reveals bilateral end-expiratory wheezes and pronounced crepitus in both knees. The cardiac examination is unremarkable. Her baseline electrocardiogram displays normal sinus rhythm without ischemic changes or conduction delays. Which of the following is the most appropriate next step in diagnostic workup?

  1. A
    Exercise electrocardiography
  2. B
    Adenosine myocardial perfusion imaging
  3. Dobutamine stress echocardiographyAnswer
  4. D
    Invasive coronary angiography
  5. E
    Coronary artery calcium scoring

Answer

Dobutamine stress echocardiography
The correct next step is dobutamine stress echocardiography. This patient has classic symptoms of stable angina and requires a non-invasive stress test to assess for inducible myocardial ischemia. Because her severe knee osteoarthritis renders her unable to exercise on a treadmill, a pharmacologic stress test is required. The two primary modalities for pharmacologic stress testing are vasodilator agents (e.g., adenosine, dipyridamole) and inotropic agents (e.g., dobutamine). Vasodilator agents are strictly contraindicated in patients with severe, active reactive airway disease because they stimulate bronchial adenosine receptors and can induce life-threatening bronchospasm. Given her active wheezing and frequent albuterol use, dobutamine is the safest pharmacologic agent to simulate stress and evaluate for regional wall motion abnormalities via echocardiography.

Step-by-Step Solution

1
Identify the clinical syndrome and pre-test probability.
The patient's exertional chest heaviness resolving with rest indicates typical stable angina, requiring further risk stratification for coronary artery disease.
To determine whether immediate invasive intervention or non-invasive diagnostic testing is warranted.
2
Assess the patient's capacity for physical exertion.
The patient uses a motorized scooter due to severe bilateral knee osteoarthritis and cannot perform a treadmill exercise test.
To choose between a physiological exercise stress test and a pharmacologic stress test.
3
Evaluate for contraindications to specific pharmacologic stress agents.
The patient has active, severe persistent asthma with wheezing on examination, which is an absolute contraindication to vasodilator agents (adenosine, dipyridamole).
To prevent potentially life-threatening iatrogenic bronchospasm.
4
Select the safest and most appropriate testing modality.
Dobutamine stress echocardiography is identified as the optimal diagnostic test.
Dobutamine serves as a safe inotropic alternative to vasodilators, and echocardiography will adequately assess for stress-induced regional wall motion abnormalities.

Key Concept

Selection of the appropriate non-invasive stress testing modality based on patient-specific physical limitations and pharmacologic contraindications.
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Topics

Diagnostic Workup and Test Sequencing

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