Case report: paradoxically reversible perfusion defects on vasodilator stress imaging in a case of metastatic coronary compression.

Background: Patients with malignancy who experience metastasis to cardiac structures may exhibit ST-segment elevations and acute coronary syndrome (ACS) through poorly understood pathophysiologic mechanisms. We present a case in which vasodilator stress cardiovascular magnetic resonance provides unique insight into one such patient who suffered from recurrent episodes resembling ACS. Case summary: A 58-year-old male with metastatic lung adenocarcinoma presented with refractory angina and dynamic inferior electrocardiogram changes. The patient was referred for adenosine stress cardiovascular magnetic resonance, revealing multiple territories of abnormal perfusion during rest with improvement during adenosine infusion. Subsequent computed tomography displayed tumour encasement of the right coronary artery. Taken together, vasodilator-responsive extrinsic compression of multiple epicardial coronary arteries was suspected. Outpatient oncology follow-up for chemoimmunotherapy initiation was arranged with the hope that reducing tumour burden might alleviate coronary compression. However, in the ensuing months, the patient's disease advanced beyond the point of which his symptoms could be controlled medically, and he was ultimately enrolled in hospice care. Discussion: Encasement of coronary arteries can result in anginal symptoms if their position impairs coronary arterial flow. The presented case highlights the unique manner in which these lesions might behave on stress cardiac magnetic resonance imaging. Clinicians who encounter such unusual findings on vasodilator stress imaging should consider metastatic lesions to the cardiac structures on the differential diagnosis.