Pulmonary Capillary Hemangiomatosis and Refractory Hypoxemia During PH Therapy

Abstract

<h3>Introduction</h3> Pulmonary capillary hemangiomatosis (PCH), a rare cause of pulmonary hypertension (PH), presents clinically with right heart dysfunction and may be indistinguishable from typical pulmonary arterial hypertension. Vasodilator therapy exacerbates hypoxemia in PCH despite improvement in heart failure symptoms. Lung transplant is the only definitive therapy. We present the case of a patient succumbing to progressive hypoxemia on PH therapy during lung transplant evaluation. Autopsy revealed PCH. <h3>Case Report</h3> A 42-year-old female with PH due to undifferentiated connective tissue disease presented with acute respiratory distress. She was diagnosed 2 years prior and initially treated with macitentan, tadalafil and diuretics with clinical improvement; however, worsening shortness of breath and new finding of hypoxemia developed after 1 year. Imaging revealed faint patchy nodular opacities initially attributed to UCTD-associated pneumonitis. Steroids and mycophenolate failed to achieve radiographic improvement. Repeat right heart catheterization showed continued elevation in pulmonary artery pressure and stably reduced cardiac output. Subcutaneous infusion of Treprostinil was initiated 2 months prior to admission, which worsened hypoxemia. Clinical diagnosis of pulmonary veno-occlusive disease (PVOD) vs PCH was suspected and lung transplant evaluation initiated. On admission, patient presented with syncope and was found to have refractory hypoxemia despite high-flow oxygen supplementation. Cardiogenic shock and hypoxemic respiratory failure ensued, resulting in hepatic and renal failure, leading to cardiac arrest and unsuccessful resuscitation. Autopsy showed PCH. <h3>Summary</h3> Refractory hypoxemia during up-titration of vasodilator therapy for PH should prompt clinical suspicion for atypical causes of PH such as PCH. Early lung transplant referral is essential if PCH/PVOD is suspected given its poor prognosis and potentially harmful responses associated with traditional PH therapy.