HISTOPATHOLOGY AIDING IN THE DIAGNOSIS OF AN ATYPICAL CASE OF AORTIC DISSECTION

Abstract

TOPIC: Cardiothoracic Surgery TYPE: Medical Student/Resident Case Reports INTRODUCTION: Aortic dissection (AD) often presents as acute severe chest or back pain and hemodynamic compromise[1,2]. Early and accurate diagnosis and treatment are crucial for survival. Multiple imaging modalities can be used to demonstrate the dissection, including Computed Tomographic Angiography (CTA), Magnetic Resonance Angiography (MRA), and Transesophageal Echocardiography (TEE). We present a case where a patient with atypical presentation of AD underwent multiple diagnostic studies with inconsistent results. CASE PRESENTATION: A 47-year-old male with history of hypertension, asthma, and tobacco use presented with sudden onset of left-hand numbness, tingling, and pain with associated changes of color in his hand. Patient had sensory deficits in the left hand and left big toe. A left upper extremity (LUE) venous duplex was unremarkable. CTA of the chest showed a filling defect in the right posterior ascending aorta suggestive of an intimal flap. Esmolol was initiated. TEE did not reveal AD. Heparin was initiated. Arterial Doppler of the LUE was negative for any atherosclerotic or thrombotic diseases or evidence of obstruction. The following day, the patient experienced crushing chest pain radiating to the back. Transthoracic echocardiogram showed filling defect in the ascending aorta. Patient was operated on emergently. Although a frank AD was not observed, a mobile pedunculated mass was reported. The affected segment of the aorta was resected and a graft was used for repair. Histopathology results showed focal adventitial hemorrhage and degenerative medial changes consistent with AD. DISCUSSION: In this case of atypical AD diagnosis was not made early due to atypical symptoms and inconclusive and inconsistent imaging studies. The definitive diagnosis was made through histopathology, as even the inspection at time of surgery was inconclusive for AD, given unusual gross appearance. Painless dissection is encountered only in 6.4% of cases [3]. Conventional CT scanning has a sensitivity of 83-95% but it drops to <80% in the ascending aorta[4-7]. MRA or TEE is typically performed next to confirm the diagnosis. Despite a sensitivity of 98%[8,9], TEE was unremarkable in this case. The features of the AD on histopathology, including the presence of the intimal tear, hemorrhage near the adventitial layer, and medial degeneration confirmed the diagnosis. In a recent large cardiovascular registry, >60% of cases of AD were first identified at autopsy[10,11]. CONCLUSIONS: This case represents a diagnostic challenge and highlights the possibility of uncommon presentation of AD, and the importance of taking the results of multiple imaging modalities into consideration to confirm the diagnosis. In this case, and due to unusual gross appearance during surgery, histopathology was necessary to confirm the diagnosis. It is extraordinarily rare to require histopathology to confirm diagnosis of AD at time of surgery. REFERENCE #1: 1.Hagan PG, Nienaber CA, Isselbacher EM, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA 2000; 283:897 REFERENCE #2: 2. Evangelista A, Isselbacher EM, Bossone E, et al. Insights From the International Registry of Acute Aortic Dissection: A 20-Year Experience of Collaborative Clinical Research. Circulation 2018; 137:1846. 3. Fatima S, Sharma K. Painless Aortic Dissection-Diagnostic Dilemma With Fatal Outcomes: What Do We Learn?. J Investig Med High Impact Case Rep. 2017;5(3):2324709617721252. 4. Nienaber CA, von Kodolitsch Y, Nicolas V, et al. The diagnosis of thoracic aortic dissection by noninvasive imaging procedures. N Engl J Med 1993; 328:1. 5. LePage MA, Quint LE, Sonnad SS, et al. 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Hosoda Y. [Pathology of aortic dissection]. Nihon Geka Gakkai Zasshi. 1996 Oct;97(10):873-8. 11. Huynh N, Thordsen S, Thomas T, Mackey-Bojack SM, Duncanson ER, Nwuado D, Garberich RF, Harris KM. Clinical and pathologic findings of aortic dissection at autopsy: Review of 336 cases over nearly 6 decades. Am Heart J. 2019 Mar;209:108-115. DISCLOSURES: No relevant relationships by Matthew Darrow, source=Web Response No relevant relationships by Muhammad Mufty, source=Web Response No relevant relationships by Pradyumna Tummala, source=Web Response