METASTATIC PULMONARY CALCIFICATION: A RARE CAUSE OF PULMONARY HYPERTENSION

Abstract

SESSION TITLE: Fellows Pulmonary Vascular Disease Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Metastatic calcification is seen at autopsy in 60-75% of CKD patients on hemodialysis (HD) due to increased calcium phosphate product (normal 40 mg2/dl2; MPC >70 mg2/dl2) (1,2). Metastatic pulmonary calcification associated with pulmonary hypertension (PH) is rare. We present a case of MPC associated combined postcapillary and precapillary PH (CpcPH). CASE PRESENTATION: A 58-year-old woman with SLE, CTD-ILD (FVC 64%, TLC 56 %), ESRD on HD since 2008 and diastolic heart failure was admitted to the hospital with worsening dyspnea, leg edema and orthopnea. Her calcium phosphate product was 61. CT chest showed diffuse ground glass opacity with mosaic perfusion, enlarged pulmonary artery (PA 4.3 cm) and chest wall calcifications. Echocardiogram showed grade 3 diastolic dysfunction, severely dilated left atrium and elevated right ventricular systolic pressure. Heart catheterization showed mean PA pressure 62 mm Hg, PA wedge pressure 29 mm Hg, transpulmonary gradient (TPG) 33, diastolic pulmonary gradient (DPG) 11, pulmonary vascular resistance 9 WU, LV end diastolic pressure 27 mm Hg, cardiac output 3.6, cardiac index 2.1. Given her severe PH, low CI and NYHA functional class IV, she was started on inhaled treprostinil with improvement in leg edema and orthopnea at 6-month follow up. DISCUSSION: Hyperphosphatemia in ESRD causes increased calcium phosphate product leading to calcium crystallization. Metastatic calcifications are usually seen in lamina propria of stomach, lung alveoli, renal tubules and interstitium(2). Acidosis between HD sessions causes leaching of calcium from bone, leading to deposition during post dialysis alkalosis. Uremia alters the configuration of tissue protein, rendering them more calcifiable. Three main CT patterns of MPC include centrilobular ground glass nodules, dense consolidation and small dense nodules(1). It is usually peripheral in distribution with upper lung zone dominance due to increased alkalinity (higher V/Q ratio causing low PaCO2) causing calcium salt deposition. Vascular calcification in chest and abdominal wall is a common finding as noted in our case. 30-50% of CKD and ESRD patients have PH. Vascular calcification can affect pulmonary arterial capacitance (low PAC in our case 0.81) and increase RV afterload. In this case, contributing factors to her PH are elevated LVEDP, ILD and ESRD (WHO group II, III and V). TPG >12 and DPG >7 suggested pulmonary vascular remodeling from shear stress and downstream pressure. This is an interesting case of MPC with associated PH. Initiation of the pulmonary vasodilator treprostinil reduced her PVR allowing for a better coupling of the RV-PA system. CONCLUSIONS: Treatment of MPC includes intensification of HD sessions and use of calcium and phosphate binders. In this case, inhaled pulmonary vasodilators for treatment of CpcPH after medical treatment optimization of other co-morbidities led to symptomatic improvement. Reference #1: Metastatic pulmonary calcification: HRCT findings in 23 cases, Radiol Bras.2017 Jul-Aug; 50(4): 231–236 Reference #2: Metastatic pulmonary calcification: State-of-the-art review focused on imaging findings, Respiratory Medicine Feb 2014 (108): 668-676 Reference #3: Pulmonary hypertension with extensive calcification in small pulmonary vessels and alveolar capillary wall in a chronic hemodialysis patient, Journal of Cardiology Cases 8 (Feb 2013) e13–e16 DISCLOSURES: No relevant relationships by Moises Cossio, source=Web Response No relevant relationships by Domingo Franco-Palacios, source=Web Response No relevant relationships by Kushagra Gupta, source=Web Response No relevant relationships by Shahzad Hussain, source=Web Response No relevant relationships by Venkateswara Kollipara, source=Web Response No relevant relationships by Toribiong Uchel, source=Web Response