Excercise-induced pulmonary hypertension and coronary artery anomaly: an unusual association

Abstract A healthy 55-year-old competitive sportsman, with familial history of early sudden cardiac death, came to our attention following the finding of asymptomatic exercise-induced myocardial ischemia (ST depression in V3- V6). Computed tomography (CT) coronary angiogram excluded atherosclerotic disease but showed a dominant right coronary artery (RCA) originating from left Valsalva sinus and with an interarterial course between the ascending aorta and the pulmonary artery. Both the trunk of the pulmonary artery and the right ventricle were reported as mildly dilated Transthoracic echocardiography showed a normal left ventricle (LV), while confirmed right ventricle (RV) dilatation, moderate tricuspid regurgitation (TR) and interatrial septal aneurysm. Stress echocardiography excluded inducible ischemia, but highlighted exercise-induced pulmonary hypertension (PH) (PAPs 25 → 70 mmHg), while a transesophageal echo confirmed a left-to-right shunt due to a 8-mm Patent Foramen Ovale (PFO). Rheumatological, thromboembolic and parenchymal lung diseases were excluded as possible causes of exercise-induced PH; a rest right heart catheterization (RHC) showed a Qp/Qs ratio at the upper limits of normal range without PH. Nuclear stress testing identified trivial asymptomatic septal ischemia. The patients started medium dose of beta-blockers and early follow-up was planned. This clinical case raises some questions: why is RV dilated? What role does PFO play? What is the cause of the inducible ischemia? What is the pathogenesis of exercise-induced PH? Pulmonary Arterial Hypertension, in early stages, often manifests only under exertion, but it is usually characterized by exercise dyspnea and low oxygen saturation. Moreover, intracardiac shunts may be involved in developing PH. In this specific case, pulmonary trunk may be expanded by pressure overload, causing the compression of aberrant RCA and consequent ischemic abnormalities. RV dilatation might be explained by exercise-induced PH itself, but it was not severe and has to be demonstrated by exercise right heart catheterization. The main questions are: which is the primary etiology of right chamber enlargement and myocardial ischemia? Which is the most appropriate therapeutic approach (i.e. conservative vs interventional)?