Should a stress test be performed inpatient or outpatient?

Inpatient vs. Outpatient Stress Testing for Chest Pain

For patients with acute chest pain who are initially conservatively managed, stress testing should be performed before discharge as an inpatient for those with intermediate to high risk features, while low-risk patients can safely undergo outpatient stress testing within 72 hours of discharge. 1

Risk Stratification to Determine Testing Location

Inpatient Stress Testing Indicated For:

• Patients with AMI who are initially conservatively managed (medical therapy without invasive coronary angiography) 1
• Intermediate-risk patients with acute chest pain 1
• Patients with definite ACS but nondiagnostic ECG and normal initial cardiac biomarkers 1
• Patients with recurrent symptoms, new ECG changes, or positive cardiac biomarkers during observation 1
• Patients with a 30-day risk of death or MACE >1% 1

Outpatient Stress Testing Appropriate For:

• Low-risk patients (30-day risk of death or MACE <1%) 1
• Patients with possible ACS who have:
  • No recurrent symptoms during observation
  • Normal or unchanged ECG
  • Normal cardiac biomarkers
  • Hemodynamic stability 1

Evidence Supporting This Approach

The 2017 AHA/ACC guidelines specifically recommend that patients with AMI who are initially conservatively managed should undergo noninvasive stress testing before discharge 1. This helps identify high-risk patients who may need invasive angiography and possible revascularization to reduce the risk of recurrent ischemia/MI.

For intermediate-risk patients, management in an observation unit is reasonable to shorten length of stay and lower cost relative to inpatient admission 1. During this observation period, stress testing can be performed to guide further management decisions.

The 2007 ACC/AHA guidelines state that low-risk patients may be discharged and referred for outpatient stress testing within 72 hours 1. These patients should be given specific instructions on activity, medications, and what to do if symptoms recur while awaiting the stress test.

Important Considerations for Test Selection

When selecting the appropriate stress test modality:

• Exercise ECG testing is appropriate for patients who can exercise and have a normal baseline ECG
• Imaging-based stress tests (echocardiography, nuclear, CMR) are preferred for patients with:
  • Abnormal baseline ECG
  • Inability to exercise
  • Higher pre-test probability of coronary disease 1

Clinical Outcomes and Cost Considerations

Research shows no significant difference in 30-day cardiovascular outcomes (death, MI, PCI, CABG) between patients receiving inpatient, outpatient, or no stress testing within 30 days 2. However, inpatient stress testing has been shown to reduce subsequent ED visits for chest pain, though the cost savings from reduced ED visits do not offset the higher initial costs of inpatient testing 3.

Potential Pitfalls and Caveats

1. Overutilization in young patients: The diagnostic yield of routine stress testing in low-risk patients under 40 years is extremely low (0.24-0.32%) 4, suggesting that routine stress testing may not be beneficial in this population.

2. Provider selection of testing modality: For lower-risk chest pain patients, allowing physicians to select the appropriate stress test modality may be more cost-effective than mandating a specific type of test 5.

3. Timing considerations: Patients who develop recurrent symptoms during observation or have new ECG changes or positive biomarkers should be admitted and not discharged for outpatient testing 1.

4. Follow-up planning: When discharging patients for outpatient stress testing, ensure clear instructions are provided regarding medication use before testing, activity restrictions, and what to do if symptoms recur 1.

By following this risk-stratified approach to stress testing location, clinicians can optimize resource utilization while ensuring appropriate evaluation of patients with chest pain.