What is the interpretation of a pharmacological stress test showing normal myocardial perfusion, left ventricular ejection fraction of 85%, and low to moderate risk for cardiac events, with findings of septal hypokinesis, transient ischemic dilatation, and coronary artery calcification on non-contrast Computed Tomography (CT) images?

From the Guidelines

Based on the stress test results, I strongly recommend a follow-up anatomical evaluation of the coronary arteries, such as a coronary CT angiogram or cardiac catheterization, due to several concerning findings. The test shows a mildly abnormal Transient Ischemic Dilatation (TID) ratio of 1.20, which can indicate balanced ischemia even when perfusion appears normal, as suggested by the 2023 AHA/ACC guideline for the management of patients with chronic coronary disease 1. Additionally, coronary artery calcification was detected on the non-contrast CT images, suggesting underlying coronary artery disease, which is a significant risk factor for cardiac events, as highlighted in the same guideline 1. While the myocardial perfusion appears normal with no evidence of ischemia, and the left ventricular ejection fraction is excellent at 85%, the presence of septal hypokinesis (likely due to Left Bundle Branch Block) combined with the TID and calcification warrants further investigation. The stress test indicates a low to moderate risk for cardiac events, but these specific findings suggest potential coronary artery disease that may not be fully captured by perfusion imaging alone, as noted in the guideline that a negative functional test for CCD does not uniformly predict a <1% annual risk of cardiovascular death or nonfatal MI 1. Prompt anatomical evaluation would help determine if there are significant coronary stenoses requiring intervention, particularly if you're experiencing cardiac symptoms, and would be in line with the recommendation to optimize anti-ischemic and preventive therapies to reduce the patient’s angina burden and improve clinical outcomes, as suggested by the 2021 AHA/ACC chest pain guideline 1. Key points to consider in the management of this patient include:

• The importance of anatomical evaluation in patients with suspected coronary artery disease, even with normal perfusion imaging
• The role of coronary artery calcification and TID in risk stratification for cardiac events
• The need for optimal medical therapy to reduce angina burden and improve clinical outcomes, as evidenced by major RCTs such as COURAGE, ISCHEMIA, and BARI-2D 1.

From the Research

Stress Test Results

• The stress test shows a pharmacological stress test protocol with excellent overall quality of the study 2.
• Attenuation artifact was present, but SPECT images using Technetium (99mTc) Sestamibi study demonstrate homogenous tracer distribution throughout the myocardium, suggestive of normal perfusion study with no evidence of ischemia 3, 4.
• The left ventricular ejection fraction was calculated to be 85, indicating good heart function 5.
• The scan indicates low to moderate risk for cardiac events, which is consistent with the results of noninvasive stress testing for coronary artery disease 3, 4.

Recommendations and Findings

• Gated SPECT imaging reveals septal hypokinesis due likely to LBBB, which may be a sign of underlying cardiac disease 2.
• Transient Ischemic Dilatation of 1.20 was observed, which may indicate some degree of cardiac stress 5.
• Coronary artery calcification was seen in non-contrast CT images, which is a marker of atherosclerosis and may be associated with an increased risk of cardiac events 6.
• The recommendations suggest that TID is mildly abnormal, and consider anatomical evaluation if indicated clinically, which is consistent with the findings of coronary computed tomography angiography vs functional stress testing for patients with suspected coronary artery disease 6.

Comparison with Other Studies

• The results of this stress test are consistent with other studies that have shown that noninvasive stress testing is a useful tool for risk stratification in patients with suspected coronary artery disease 3, 4.
• However, other studies have also shown that coronary computed tomography angiography may be a more accurate diagnostic tool for detecting coronary artery disease, especially in patients with suspected CAD 2, 6.
• The relationship between stress test findings and anatomic or functional extent of coronary artery disease assessed by coronary computed tomography angiography-derived fractional flow reserve is complex and requires further study 5.