What is the next step in management for a patient with an abnormal Myocardial Perfusion Imaging (MPI) stress study using Lexiscan (regadenoson)?

Management of Abnormal Myocardial Perfusion Imaging (MPI) Stress Study with Lexiscan

For patients with an abnormal Myocardial Perfusion Imaging (MPI) stress study using Lexiscan (regadenoson), the next step in management should be coronary angiography to evaluate for significant coronary artery disease requiring intervention. 1

Understanding the Significance of Abnormal MPI Results

An abnormal MPI stress test with Lexiscan indicates the presence of myocardial ischemia and/or infarction, which has significant prognostic implications:

• Moderate to large reversible perfusion defects carry the greatest risk of perioperative cardiac death or MI 1
• The extent and severity of ischemia provide powerful predictors of cardiac death risk 2
• The presence of abnormal perfusion is associated with a 1.5-fold increased risk of adverse cardiac events 3

Management Algorithm

1. Assess the Type and Extent of Perfusion Defect

• Reversible defects: Indicate active ischemia - inadequate blood flow during stress

  • Higher likelihood of benefit from revascularization 2
  • Associated with increased risk of cardiac events 1

• Fixed defects: Indicate prior infarction/scarring

  • Higher cardiac death risk, especially if multivessel 2
  • Less predictive of perioperative events but predict long-term cardiac events 1

• Size/extent of defect: Larger defects indicate worse prognosis and higher risk 2

2. Proceed to Coronary Angiography

Coronary angiography is the appropriate next step for patients with:

• Moderate to large areas of myocardial ischemia on MPI 1
• Persistent symptoms despite medical therapy 1
• Abnormal MPI with evidence of significant ischemia 1

This approach is supported by ACC/AHA guidelines which indicate that coronary angiography is reasonable to further assess risk in patients with:

• Depressed LV function (EF <50%) and moderate risk criteria on noninvasive testing 1
• Inconclusive prognostic information after noninvasive testing 1
• Unsatisfactory quality of life due to angina with preserved LV function and intermediate risk criteria 1

3. Consider Special Situations

• Balanced ischemia: In some cases, severe multivessel disease may produce "balanced ischemia" that can be falsely negative on MPI 4

  • If clinical suspicion remains high despite a normal MPI, consider CCTA with FFRCT

• Left bundle branch block: If the patient has LBBB, note that pharmacological stress MPI with regadenoson is preferred over exercise stress imaging 1

Important Caveats

• Avoid routine coronary angiography: Guidelines specifically state that routine preoperative coronary angiography is not recommended (Class III: No Benefit) 1

• False positives: Be aware that abnormal MPI results may be false positives. In one study, 50% of patients with abnormal MPI who underwent catheterization had false-positive results 5

• Rare complications: Although rare, regadenoson has been associated with myocardial infarction during testing, likely due to coronary steal phenomenon 6

• Consider patient-specific factors: The decision for coronary angiography should take into account:

  • Severity and extent of perfusion defects
  • Patient symptoms
  • Left ventricular function
  • Comorbidities
  • Patient preferences

By following this evidence-based approach, you can appropriately manage patients with abnormal MPI stress studies using Lexiscan to reduce morbidity and mortality from coronary artery disease.