Unilateral absence of pulmonary artery complicated by severe pulmonary hypertension: favorable response to parenteral therapy

TOPIC: Pulmonary Vascular Disease TYPE: Fellow Case Reports INTRODUCTION: Unilateral absence of pulmonary artery (UAPA) is a rare disorder that can present as an isolated lesion or in association with other congenital heart defects. An important complication of UAPA is the development of pulmonary hypertension (PH). Herein, we discuss a patient with severe PH in the setting of congenital UAPA and highlight the hemodynamic response to combination vasodilator therapy that included parenteral treprostinil. CASE PRESENTATION: A 58-year-old female with a history of congenital left UAPA, left lung hypoplasia and severe PH presented for evaluation of repeated syncopal episodes on minimal exertion. Two years prior to presentation, RHC showed mPAP 56 mmHg, PAWP 11 mmHg, CO 3.63 L/min, CI 1.9 L/min/m2, and PVR 12.4 WU. The patient was receiving riociguat 2.5 mg po TID, ambrisentan 10 mg po daily, and selexipag 1600 mcg po BID. She was NYHA FC IV and required oxygen at 6 L/min via oxymizer. Upon presentation, she was severely hypoxic requiring HFNC at 50 L/min and fraction of inspired oxygen of 0.9. Evaluation revealed Pro-BNP of 6170 pg/ml and cardiac echo showed an EF of 45%, severe RV dilation with severe hypokinesis and RVSP of 100 mmHg. Chest CT with contrast showed absence of the left pulmonary artery, enlargement of the main and right pulmonary arteries without pulmonary embolism, hyperinflation of right lung, and hypoplasia of the left lung. PFTs showed TLC 64%, FEV1/FVC 86, FEV1 43%, FVC 39%, and DLco 23% of predicted. VQ scan showed marked decreased perfusion of the left lung, decreased ventilation of the anterior left lung with some patchy ventilation of the posterior aspect of the left lung, and normal right lung perfusion. Repeat RHC showed significant worsening of hemodynamics with mPAP of 76 mmHg and PVR of 28.6 WU. The patient was transitioned from selexipag to IV treprostinil with rapid titration to 40 ng/kg/min over a few days. There was improvement in her dyspnea and oxygenation with weaning of supplemental oxygen from HFNC to 6 L/min oxymizer. Pro-BNP trended down to 332 pg/ml and she had no recurrence of syncopal episodes. The patient was transitioned from IV to SQ treprostinil and further titration of SQ treprostinil was continued at home to 64 ng/kg/min. After 2 months, repeat echo showed improvement with an EF of 67%, moderate RV dilation with mild hypokinesis and RVSP 60 mmHg. Repeat RHC showed hemodynamic improvement with mPAP of 51 mmHg and PVR of 10.5 WU. DISCUSSION: Patients with UAPA and lung hypoplasia who develop PH pose a management dilemma as no treatment consensus exists. Therapeutic approaches should be based on severity of symptoms, pulmonary artery anatomy, associated cardiovascular anomalies, collateral circulation and hemodynamic parameters. CONCLUSIONS: Select patients with severe PH may benefit from a cautious trial of combination vasodilator therapy under close observation. REFERENCE #1: Kruzliak P, Syamasundar RP, Novak M, Pechanova O, Kovacova G. Unilateral absence of pulmonary artery: pathophysiology, symptoms, diagnosis and current treatment. Arch Cardiovasc Dis. 2013;106(8-9):448-454. doi:10.1016/j.acvd.2013.05.004 DISCLOSURES: Speaker/Speaker's Bureau relationship with United therapeutics Please note: $5001 - $20000 by Karim El-Kersh, source=Web Response, value=Honoraria Removed 04/21/2021 by Karim El-Kersh, source=Web Response Advisory Committee Member relationship with United therapeutics Please note: $1001 - $5000 by Karim El-Kersh, source=Web Response, value=Consulting fee Removed 04/21/2021 by Karim El-Kersh, source=Web Response Advisory Committee Member relationship with Actelion Please note: $5001 - $20000 by Karim El-Kersh, source=Web Response, value=Consulting fee Removed 04/21/2021 by Karim El-Kersh, source=Web Response Advisory Committee Member relationship with United Therapeutics Please note: Current Added 04/23/2021 by Karim El-Kersh, source=Web Response, value=Consulting fee Advisory Committee Member relationship with Actelion Please note: 2019 and 2020 Added 04/23/2021 by Karim El-Kersh, source=Web Response, value=Consulting fee Speaker/Speaker's Bureau relationship with United Therapeutics Please note: Current Added 04/29/2021 by Karim El-Kersh, source=Web Response, value=Honoraria Advisory Committee Member relationship with United Therapeutics Please note: Current Added 04/29/2021 by Karim El-Kersh, source=Web Response, value=Honoraria Advisory Committee Member relationship with Actelion Please note: 2019 and 2020 Added 04/29/2021 by Karim El-Kersh, source=Web Response, value=Honoraria Consultant relationship with Acceleron Pharma Please note: Current Added 04/29/2021 by Karim El-Kersh, source=Web Response, value=Consulting fee No relevant relationships by Meliha Hrustanovic-Kadic, source=Web Response