What is the interpretation of a pharmacological stress test with Technetium (99mTc) Sestamibi study showing normal perfusion, left ventricular ejection fraction of 85%, and low to moderate risk for cardiac events, in the presence of septal hypokinesis, Transient Ischemic Dilatation (TID), and coronary artery calcification?

From the Guidelines

The patient's stress test results indicate a need for further anatomical evaluation due to a mildly abnormal Transient Ischemic Dilatation (TID) ratio and other concerning findings, despite a normal cardiac perfusion study. The pharmacological stress test with Technetium Sestamibi shows homogenous tracer distribution, suggesting normal perfusion with no evidence of ischemia 1. However, several findings are noteworthy: a mildly abnormal TID ratio of 1.20, septal hypokinesis likely due to Left Bundle Branch Block (LBBB), and coronary artery calcification visible on non-contrast CT images. Despite the excellent left ventricular ejection fraction of 85%, these findings collectively suggest a low to moderate risk for cardiac events. Given the mildly abnormal TID ratio, which can indicate balanced ischemia or multivessel disease even in the absence of perfusion defects, further anatomical evaluation is recommended, as suggested by guidelines for the management of stable angina pectoris 1. This would typically involve a coronary CT angiogram or conventional coronary angiography to directly visualize the coronary arteries and assess for significant stenosis, particularly if the patient has symptoms consistent with cardiac ischemia or other clinical risk factors. The use of exercise stress imaging is recommended for patients who are able to exercise, but pharmacologic stress is useful for risk stratification in patients who are unable to exercise 1. In patients with a normal stress perfusion study, the subsequent rate of cardiac death and myocardial infarction is low, approximately <1% per year, which is nearly as low as that of the general population 1. However, abnormal findings on stress perfusion scintigraphy have been associated with severe CAD and subsequent cardiac events. Therefore, further evaluation with a coronary CT angiogram or conventional coronary angiography is recommended to assess for significant stenosis and guide management.

From the Research

Stress Test Results Summary

• The stress test results indicate a low to moderate risk for cardiac events, with a left ventricular ejection fraction of 85 and no evidence of ischemia on SPECT images using Technetium (99mTc) Sestamibi study 2.
• The presence of attenuation artifact and septal hypokinesis due to LBBB were noted, as well as transient ischemic dilatation of 1.20 2.
• Coronary artery calcification was seen in non-contrast CT images, which may be associated with a higher cardiac event rate 3.

Pharmacological Stress Test Protocol

• The study highlights the importance of considering the patient's clinical status and characteristics when choosing a pharmacological stress test agent 2.
• Different pharmacological agents are available, and the choice of agent depends on the patient's medications and characteristics 2.
• The study also discusses the indications, contraindications, and precautions for stress test modalities, including pharmacological stress tests 2.

Diagnostic Accuracy and Coronary Calcification

• The presence of coronary calcification may cause artifacts in computed tomography coronary angiography (CTCA), but the diagnostic accuracy of CTCA is still high in patients with hypertension 4.
• Ultra-high-resolution CT (UHR-CT) may be effective in overcoming the limitations of conventional CT for accurately evaluating coronary artery stenoses in severely calcified vessels 5.
• The study suggests that UHR-CT may be a useful tool for assessing patients with severe coronary artery calcification, with high diagnostic confidence scores and good sensitivity and specificity for stenosis assessment 5.

Recommendations and Future Directions

• The study recommends considering anatomical evaluation if indicated clinically, given the mildly abnormal transient ischemic dilatation (TID) result 2.
• The choice of noninvasive diagnostic modality, including stress testing and noninvasive coronary imaging, depends on the patient's individual characteristics and clinical status 6.
• Further research is needed to determine the best test for each patient, taking into account the strengths and limitations of each diagnostic modality 6.