Myocardial bridge: an unrecognized cause of chest pain in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by an increased pulmonary vascular resistance resulting in progressive right ventricular hypertrophy and failure. While dyspnea on exertion is the leading symptom at diagnosis, the occurrence of chest pain, although less frequently observed, is an alarming symptom that requires immediate diagnostic work-up. Here we report the case of a 44-year-old woman with severe end-stage group 1 PAH who had repetitive occurrences of chest pain that led to frequent emergency room visits with documented signs of myocardial ischemia on EKG and troponin leaks. A computed tomography (CT) angiogram of the coronary arteries revealed the presence of a myocardial bridge (MB). An invasive coronary angiogram confirmed a MB over the left anterior descending (LAD) artery compressing the lumen of the LAD. As the patient was deteriorating on maximal medical PAH therapy, she was listed for, and subsequently received, a bilateral lung transplantation. Recognizing that the MB would pose a significant risk for ischemia during surgery as well as continuing source for chest pain after lung transplantation, the MB was surgically “unroofed” during the transplant surgery. The patient did well after surgery and did not complain of any residual chest pain. In conclusion, a MB compressing a segment of the coronary artery could be an under-diagnosed, but potentially not so rare cause of recurrent chest pain in PAH patients, which requires specialized diagnostic evaluation and treatment