Treatment of left main coronary artery compression in the setting of unpalliated congenital heart disease: a case series.

Background: Left main coronary artery compression syndrome (LMCS) is a well-characterized phenomenon resulting from compression of the left main coronary artery (LMCA) between the aorta and an enlarged pulmonary arterial trunk. The development of LMCS is usually described in the context of severe pulmonary arterial hypertension. Cases of LMCS, in the context of unpalliated congenital heart disease (CHD), are complex clinical scenarios that challenge traditional treatment paradigms. Case summary: Here, we discuss two thought-provoking patients with unpalliated CHD complicated by severe pulmonary hypertension (PH). Both patients developed LMCS, one with severe non-ST elevation myocardial infarction and the other with refractory angina. Their pulmonary vascular resistance was severely elevated despite pulmonary vasodilator therapy, and concomitant surgical correction of their CHD in addition to bypass grafting was deemed high risk. They underwent successful percutaneous coronary intervention (PCI) of the LMCA with drug-eluting stents. Discussion: Pulmonary hypertension can develop in the setting of long-standing unpalliated CHD. Surgical correction of congenital heart defects may be performed in select patients with systemic-to-pulmonary shunts, contingent on the status of PH severity. Pulmonary vasodilator therapy modulates haemodynamics to ensure surgical correction without risk of cardiopulmonary demise-termed the 'treat and repair' strategy. LMCS, an increasingly recognized phenomenon in patients with long-standing PH, is a notable complicating factor in the 'treat and repair' strategy. We introduce the concept that PCI of the LMCA may bridge patients to corrective surgery for CHD by allowing time for optimization of their pulmonary vasodilator therapy.