Abstract 12982: Between a Rock and a Hard Place: Stiff Left Atrial Syndrome in a Patient With Hereditary Rickets

Abstract

Introduction: Stiff left atrial syndrome (SLAS) is an uncommon cause of pulmonary hypertension (PH) that has been described as a complication of ablation for atrial fibrillation; here we describe a unique case of SLAS in the setting of extensive left atrial calcification from the treatment of hereditary hypophosphatemia (HH). Case Presentation: A 44-year-old woman with a history of HH presented for evaluation of progressive exertional dyspnea. Previous treatment with calcitriol and phosphate had been complicated by severe calcific mitral and aortic stenosis requiring aortic and mitral valve replacement eight years prior. She reported initial improvement in her symptoms after surgery, but more recently had noted worsening dyspnea and edema despite escalating her home diuretic dose. TTE was notable for moderately severe PH with no evidence of valvular or ventricular dysfunction. Chest CT showed extensive left atrial mural calcification (Figure A) with corresponding calcium visible in the wall of the left atrium on TTE (Figure B). The patient was admitted and underwent IV diuresis followed by RHC confirming mPAP of 41mmHg with a PCWP of 20mmHg and prominent V waves to 33mmHg (Figure C-D). PCWP was confirmed by wedge oxyhemoglobin saturation. Symptoms were improved but not resolved with additional diuresis. Discussion: In this patient with metastatic calcinosis related to the treatment of her HH, we believe her PH is most likely secondary to SLAS due to marked circumferential left atrial calcification. SLAS is characterized by decreased left atrial compliance, leading to large V waves in the absence of mitral regurgitation or an elevated LVEDP. Beyond diuresis, there are no proven treatments for PH due to SLAS.