Abstract Introduction Pulmonary veno-occlusive disease (PVOD) is a rare cause of pre-capillary pulmonary hypertension (PH) characterized by progressive fibrotic occlusion of pulmonary venules. Diagnosis is challenging because clinical and physiologic findings overlap with other forms of PH. Case Report A 53-year-old woman with severe pre-capillary PH presented with progressively worsening acute on chronic hypoxemic respiratory failure. Prior evaluation included echocardiography showing severe PH (right ventricular systolic pressure 77 mmHg) without left-sided disease. Right-heart catheterization confirmed pre-capillary physiology: mean pulmonary arterial pressure 47 mmHg, pulmonary artery wedge pressure 7 mmHg, cardiac output 3.30 L/min with cardiac index 1.63 L/min/m², pulmonary vascular resistance 12.12 Wood units, and left ventricular end-diastolic pressure 12 mmHg. Pulmonary function testing demonstrated moderate restriction with severely reduced DLCO. Outpatient V/Q scan detected multiple large bilateral mismatched perfusion defects, interpreted as high-probability pulmonary embolism, prompting a working diagnosis of CTEPH; however, serial CT angiography studies were negative for thromboembolic disease and no confirmatory pulmonary angiography was performed. Serologic evaluation for connective tissue and autoimmune etiologies was unrevealing. Admission CT showed progression of interlobular septal thickening, diffuse/centrilobular ground glass opacities, mediastinal lymphadenopathy, and pulmonary venous involvement including thrombosis. Bronchoalveolar lavage showed hemosiderin-laden macrophages without infection. In the setting of severe pre-capillary PH, profoundly reduced DLCO, large V/Q defects without CTA-proven emboli, and rapidly progressive CT findings classic for PVOD, a presumptive diagnosis of PVOD was made. Genetic testing for EIF2AK4 and emergent lung-transplant referral were initiated, but the patient decompensated rapidly; attempts at VA-ECMO during ECPR were unsuccessful. Discussion Characteristic findings that should prompt consideration of PVOD include abnormal V/Q scan without evidence of pulmonary embolism on CTPA or pulmonary angiogram, triad of classic abnormal chest CT findings (septal thickening, GGOs, and mediastinal lymphadenopathy) in the absence of left heart disease, profound hypoxemia and severely reduced DLCO. Although V/Q scans are frequently normal in patients with PVOD, there are case reports reporting mismatched defects in V/Q in PVOD likely due to involvement of larger pulmonary veins leading to segmental perfusion defects. In our case, initial misdiagnosis of CTEPH was based on over-reliance on a positive V/Q, absence of a confirmatory pulmonary angiography, and overlooking the abnormal parenchymal findings with significant hemodynamic abnormalities. PVOD is a rapidly progressive disease with lung transplantation being the only definitive therapy making early identification and referral to lung transplant extremely important to expedite care. This abstract is funded by: none
Khurana et al. (Fri,) studied this question.