SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Stanford type A dissection of the proximal aorta is considered a surgical emergency due to high early mortality (1). The weakening of the aortic wall along with elevated shear stress may predispose to an aortic dissection. Concurrently, systemic amyloidosis tends to deposit in the vasa-vasorum, which leads to the frailty of the aortic vascular layers. Here we present an unusual case in which an asymptomatic type A aortic dissection was diagnosed due to suspected aortic amyloidosis. CASE PRESENTATION: A 73 year old woman with a history of uncontrolled hypertension (HTN) and diabetes mellitus presented for elective cardiac magnetic resonance imaging (MRI) due to suspected cardiac amyloidosis after testing positive for hereditary ATTR amyloid gene mutation. Her family history was significant for amyloid cardiomyopathy in two siblings. She had no exertional symptoms, and physical exam was only notable for a soft systolic ejection murmur at the left sternal border. Her electrocardiogram showed normal sinus rhythm with normal intervals. MRI unexpectedly noted a type A aortic dissection arising at the level of the sinotubular junction extending up the ascending aorta and down to the level of the iliac bifurcation with no evidence of myocardial amyloid deposition. She remained clinically asymptomatic but was transferred to the cardiac intensive care unit for initiation of intravenous antihypertensive therapy. Cardiac surgery was consulted and performed an urgent ascending hemi-arch replacement. Aortic tissue pathology was negative for amyloid protein. Subsequent outpatient follow-up showed stable aortic repair with chronic type B aortic dissection, and she continued to remain asymptomatic. DISCUSSION: It has been observed that 6.4% of aortic dissections are clinically subtle in presentation resulting in an increased mortality (2). Although MRI & pathologic analysis did not demonstrate amyloidosis, microvascular intramural amyloid deposition in the aorta remains possible. In this case, chronic uncontrolled HTN with age related degeneration of the aortic wall were likely the primary underlying factors. CONCLUSIONS: This case illustrates an unusual clinically silent presentation of a catastrophic illness. Although the management of silent Type A dissection typically require early surgical intervention, to improve survival, late asymptomatic presentations have been observed (3) Reference #1: Mehta RH, Suzuki T, Hagan PG, Bossone E, Gilon D, Llovet A, et al. Predicting Death in Patients With Acute Type A Aortic Dissection. Circulation. 2002 Jan 15;105(2):200–6. Reference #2: Park SW, Hutchison S, Mehta RH, Isselbacher EM, Cooper JV, Fang J, et al. Association of Painless Acute Aortic Dissection With Increased Mortality. Mayo Clin Proc. 2004 Oct 1;79(10):1252–7. Reference #3: 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: Document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adultThe Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J. 2014 Nov 1;35(41):2873–926. DISCLOSURES: No relevant relationships by Benjamin Kenigsberg, source=Web Response Removed 06/24/2020 by Benjamin Kenigsberg, source=Web Response No relevant relationships by Omar Yacob, source=Web Response