In this case, the constellation of severe PH with marked dilatation of the PAs seen on chest radiograph, as well as anginal symptoms, raised concern for extrinsic compression of the coronary arteries. Cardiology consultation resulted in recommendation for CA to simultaneously delineate anatomy and potentially intervene. CA demonstrated 80% narrowing of the LMCA at the ostia (Fig 2, see arrow). IVUS confirmed the narrowing was secondary to extrinsic compression from the PA opposed to atherosclerosis. Given case series demonstrating that PCI can be performed safely with good technical success regarding opening and stabilizing the compressed LMCA, the decision was made to proceed with placement of a bare metal stent in the LMCA. CA and IVUS confirmed 0% residual stenosis of the LMCA, as seen in Figure 3. The importance of PA dilation in causing extrinsic compression of the LMCA is also highlighted in this case. The PA trunk and aortic root diameters were 52 mm and 22 mm, respectively, with a resultant ratio of 2.36. The patient was initiated on clopidogrel 75 mg daily and aspirin 81 mg daily. Additionally, given the severely reduced cardiac index, treatment with IV treprostinil was subsequently initiated; however, this had to be discontinued secondary to intolerance of side effects and lack of social support. At 9-month follow-up she remains free of anginal symptoms.