INTRODUCTION: We present a case of a rare congenital pulmonary vascular anomaly presenting as pulmonary hypertension in an adult.
CASE PRESENTATION: A 52-year-old woman presented to the emergency room with a two week history of progressively worsening shortness of breath and bilateral lower extremity edema. She was afebrile, with a blood pressure of 130/82 mm Hg, heart rate of 91 beats per minute, respiratory rate of 23 breaths per minute, and pulse oxygen saturation of 91% on 4 liters via nasal cannula. Physical examination was significant for mild jugular venous distension, no cardiac murmurs, clear lung sounds, and 1+ pitting edema to mid-calf bilaterally. A chest radiograph revealed left pulmonary artery enlargement. Transthoracic echocardiography showed a pulmonary artery pressure (PAP) of 120/50 mm Hg and an ejection fraction of 55%. A bubble study was negative for any intracardiac shunt. There was no evidence of collagen vascular disease, underlying pulmonary or hepatic disease, or HIV infection. As part of an evaluation for thromboembolic disease, lower extremity duplex ultrasound was negative, but a ventilation-perfusion lung scan showed absence of perfusion to the right lung, with normal ventilation [Fig 1]. A CT pulmonary angiogram [Fig 2] showed no intra-arterial filling defects, but massive enlargement of the main pulmonary arterial trunk and left pulmonary artery with proximal right pulmonary artery interruption. Intercostal and chest wall arteries on the right were dilated consistent with systemic collateral flow to the right lung. Right heart catheterization and pulmonary angiography confirmed isolated proximal right main artery interruption with a PAP of 92/29 and mean PAP of 58 mm Hg. The patient was diagnosed with pulmonary arterial hypertension (PAH) complicating congenital proximal pulmonary artery interruption. Because of the lack of visualization of a distal pulmonary artery and the chronic severe nature of the pulmonary hypertension, she was not considered a surgical candidate. She was medically optimized on sildenafil, lasix, digoxin, and anticoagulation.
DISCUSSIONS: Proximal interruption of the pulmonary artery is a rare congenital anomaly. Although previously termed unilateral absence of the pulmonary artery because of the apparent termination before or at the hilum, proximal interruption is a more accurate description since the vascular network within the ipsilateral lung is intact and patent. The affected lung is perfused via systemic collateral vessels.1,2 Cardiac malformations are less frequent with right-sided proximal interruption. A subgroup of patients with right proximal pulmonary artery interruption without cardiac anomalies or pulmonary hypertension in infancy usually survive to adulthood. These individuals experience recurrent hemoptysis or pulmonary infections. Many patients remain asymptomatic through adulthood, the condition first being recognized during evaluation for abnormal chest radiograph. Our patient presented with severe PAH and cor pulmonale due to right proximal pulmonary artery interruption. Since she had been asymptomatic most of her life, PAH most likely developed over time as a complication of high flow through the pulmonary arterial system in the left unaffected lung. Our case stresses the importance of seeking underlying conditions in patients who present with PAH. Our patient's congenital anomaly was discovered during a work-up for thromboembolic disease as a possible cause for severe pulmonary hypertension. Since the pathophysiology of pulmonary hypertension was similar in our patient, we initiated treatment with sildenafil.
CONCLUSION: This is an unusual case of pulmonary hypertension, which in the course of work-up for an underlying cause was found to be due to a rare congenital anomaly. It illustrates the importance of the recommended investigation for associated conditions in patients with newly recognized pulmonary arterial hypertension.
DISCLOSURE: John Cho, No Financial Disclosure Information; No Product/Research Disclosure Information