Left main coronary artery stenosis presenting with negative myocardial perfusion imaging: a case report of balanced ischaemia

Myocardial perfusion imaging (MPI) stress testing using technetium sestamibi is a non-invasive tool for diagnosing and risk-stratifying patients with coronary artery disease. Despite its utility, MPI stress testing exhibits various limitations.

An 80-year-old male presented with severe non-radiating exertional epigastric pain. Four months earlier, an MPI test was low risk with no significant perfusion defect. High-sensitivity cardiac troponins peaked at 97 ng/L with a delta value of 25. Left cardiac catheterization revealed a 99% calcified stenosis in the left main coronary artery. The patient underwent emergent coronary artery bypass grafting for refractory angina.

A critical left main coronary artery stenosis occurred despite a recent negative stress MPI. False-negative MPI can occur with balanced ischaemia in multi-vessel and left main coronary artery disease. This case underscores the importance of cautiously interpreting MPI results in intermediate/high-risk patients to identify balanced ischaemia.