Anatomical Imaging Helps to Rule out LMD in Severe or Moderate Ischemia: ISCHEMIA

Key findings of the study:

• Among 5,146 patients, the researchers observed that 414 (8%) had LMD.
• They found that the predictors of LMD were older age, male sex, absence of prior myocardial infarction, transient ischemic dilation of the left ventricle on stress echocardiography, the magnitude of ST-segment depression on ETT and peak metabolic equivalents achieved on ETT.
• They noted that the models were weakly predictive of LMD (C-index 0.643 and 0.684).

The authors concluded, "In patients with moderate or severe ischemia, clinical and stress testing parameters were weakly predictive of LMD on CTA. For most patients with moderate or severe ischemia, anatomical imaging is needed to rule out LMD."

In an accompanying editorial, Dr Waleed T. Kayani and his team wrote, "Senior et al, help generate more questions and will help lay the foundation for future investigations. As for the clinical question, based on this and all prior evidence, the answer remains that we need to apply all tools at hand. A careful assessment of a patient's risk factor profile and noninvasive imaging results can help guide. But, to accurately rule out LMD, for now, anatomical imaging remains the modality of choice".

In a summary report, Dr Debabrata Mukherjee wrote, "This post hoc study suggests that stress testing offered only modest incremental value over clinical parameters for prediction of LMD in those with moderate or severe ischemia. Furthermore, transient ischemic dilation by stress echocardiography, and the magnitude of ST-segment depression, and low achieved workload by ETT were associated with LMD independent of clinical factors but, the discriminatory capacity of the model was modest. There was high concordance of CTA and invasive angiography for LMD in the ISCHEMIA trial and for most patients, exclusion of LMD will require anatomical imaging, with either CTA or invasive coronary angiography."