What is the best course of action for a patient with recurrent chest pain, a strong family history of cardiovascular disease, and a history of drug abuse, who experiences immediate relief with nitroglycerin?

Management of Recurrent Chest Pain with Nitroglycerin Response

The patient should undergo a cardiac stress test or coronary CT angiography before proceeding directly to left heart catheterization, as response to nitroglycerin alone is not a reliable predictor of coronary artery disease. 1, 2, 3

Clinical Presentation Assessment

The patient's presentation has several concerning features:

• Substernal chest pain radiating to the back
• Associated symptoms: nausea, diaphoresis, shortness of breath
• Immediate relief with nitroglycerin (twice)
• Strong family history of cardiovascular disease
• History of drug abuse

While these symptoms are concerning for obstructive coronary artery disease (CAD), the relief with nitroglycerin alone cannot be used to confirm a cardiac etiology.

Diagnostic Value of Nitroglycerin Response

According to the ACC/AHA guidelines, "the relief of chest pain with nitroglycerin is not predictive of ACS" 1. Multiple studies have demonstrated that nitroglycerin relief does not reliably distinguish between cardiac and non-cardiac chest pain:

• In one study, nitroglycerin relieved chest pain in 35% of patients with documented ACS compared with 41% of patients without ACS 1
• Another study found the positive likelihood ratio for having CAD if nitroglycerin relieved chest pain was only 1.1 (0.96-1.34) 2
• Research shows no significant difference in pain response to nitroglycerin between patients with and without cardiac chest pain 4

Risk Assessment

The patient's presentation warrants risk stratification using validated tools such as the TIMI Risk Score 1. Risk factors include:

• Multiple episodes of chest pain within a short timeframe
• Strong family history of cardiovascular disease
• History of drug abuse (potential cocaine-induced coronary vasospasm)

Recommended Diagnostic Approach

1. Initial evaluation:

   • Complete 12-lead ECG (should be performed within 10 minutes of presentation) 1
   • Serial cardiac troponin measurements at presentation and 3-6 hours after symptom onset 1
   • Basic metabolic panel and complete blood count

2. Non-invasive testing (before proceeding to catheterization):

   • Exercise stress testing, stress echocardiography, or nuclear perfusion imaging
   • Coronary CT angiography (particularly useful if intermediate pre-test probability)

3. Invasive testing:

   • Left heart catheterization should be reserved for patients with:
     • Positive non-invasive testing
     • High-risk features (e.g., elevated troponins, dynamic ECG changes)
     • Recurrent symptoms despite medical therapy

Pitfalls to Avoid

1. Do not rely on nitroglycerin response alone to diagnose CAD or determine need for catheterization 2, 3, 4
2. Do not overlook non-coronary causes of chest pain that may respond to nitroglycerin (e.g., esophageal spasm, aortic dissection) 5
3. Do not delay appropriate risk stratification in patients with concerning clinical features

Treatment Considerations

While diagnostic evaluation is ongoing, appropriate medical therapy should include:

• Aspirin 81-325 mg daily
• Consider beta-blockers if no contraindications
• Nitroglycerin as needed for symptom relief
• Risk factor modification

Follow-up Recommendations

• Close follow-up within 1-2 weeks regardless of initial testing results
• Patient education regarding when to seek emergency care (chest pain unrelieved by nitroglycerin after 3 doses or lasting >20 minutes) 1
• Development of a personalized action plan for recurrent symptoms

Remember that while the patient's symptoms are concerning for CAD, a systematic approach to diagnosis is warranted rather than proceeding directly to invasive catheterization based solely on nitroglycerin response.