Myocardial ischemia in the setting of extrinsic coronary compression: two case reports.

Background: Myocardial ischemia occurs in the setting of inadequate or complete cessation of blood supply to the myocardium. While atherosclerosis is the most common cause; other causes have been identified. Rare cases can be caused by extrinsic compression of the coronaries by a dilated pulmonary artery (PA) or by mechanical obstruction from nearby chest tubes or drains. We present two cases of myocardial ischemia-driven malignant arrhythmia leading to cardiac arrest caused by obstruction of the coronary blood flow from external compression. Case Description: In the first case, venous bypass graft compression from a chest tube postoperatively was noted and in the second case left main coronary artery (LMCA) compression from a dilated PA secondary to pulmonary artery hypertension (PAH) was seen. Diagnosis of these two cases was made via emergent coronary angiogram and intravascular ultrasound (IVUS) and treated by placing a drug eluting stent (DES) in LMCA compression and by adjusting the chest tube and placing a DES in the venous bypass graft with the restoration of flow. We also review the available literature regarding the incidence, diagnosis, and management of this rare entity. Conclusions: Overall, extrinsic compression of the coronaries is rare, therefore clinicians need to be aware of this infrequent process, to allow for appropriate diagnosis, management, and to prevent excess morbidity and mortality from this rare complication.