Anomalous Bronchial Artery Origin - Canary in the Coal Mine - For Diagnosing Chronic Thromboembolic Pulmonary Hypertension.

Abstract

Anomalous bronchial artery origins may have clinical implications beyond their anatomical curiosity. In this case, identification of such an anomaly led to the diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH). A 49-year-old male with a history of recurrent deep vein thrombosis (DVT) and pulmonary embolism (PE) on anticoagulation presented with chest pain and shortness of breath. Laboratory analysis was remarkable for a troponin peak of 14.74 ng/ml, a brain natriuretic peptide level of 602 pg/ml and a D-dimer level of 0.62 μg/ml. Electrocardiogram showed non-specific ST elevation in the anterolateral and inferior leads. Computed tomography angiography (CTA) of the chest was positive for PE involving the right lower lobe pulmonary arterial tree. Echocardiogram showed reduced left ventricular function (ejection fraction 38%) and akinesis of the antero-apical and infero-apical segments. Cardiac catheterization revealed non-obstructive coronary arteries, and an anomalous origin of a right bronchial artery from the right coronary artery. The right bronchial hypertrophied as it supplied collateral flow to the occluded right pulmonary artery. This anomaly and the patient's history of multiple DVT/PEs while on therapeutic levels of warfarin with near normal D-dimer levels raised suspicion for a false positive PE. Pulmonary angiogram revealed chronic occlusion in branches of the right pulmonary artery, mean pulmonary artery pressure of 36 mmHg and no acute thrombus. Ventilation-perfusion scan confirmed the diagnosis of CTEPH. The patient underwent successful pulmonary thromboendarterectomy and subsequently had normalization of mean pulmonary artery pressure. This case underscores the importance of a comprehensive diagnostic approach, and consideration of alternative explanations for imaging findings, that unveiled the diagnosis of a complex and life-threatening condition such as CTEPH.

Learning points: This case underscores the diagnostic significance of identifying anomalous bronchial artery origin which played a crucial role in the diagnosis of the underlying chronic thromboembolic pulmonary hypertension (CTEPH).It is important to understand the limitations of computed tomography angiography (CTA) chest for diagnosis of CTEPH.