J Thorac Cardiovasc Surg 2003;125:1546-1548
© 2003 The American Association for Thoracic Surgery
Proximal prolapse of aortic intimal flap: A rare complication of acute type A aortic dissection
G. Hossein Almassi, MD Milwaukee, Wis
From the Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, Wis.
Received for publication July 30, 2001. Accepted for publication Feb 15, 2002.
Address for reprints: G. Hossein Almassi, MD, Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, Froedtert East Clinic, PO Box 26099, Milwaukee, WI 53226 (E-mail: galmassi{at}mcw.edu).
Acute type A aortic dissection requires emergency surgical repair to prevent the known life-threatening complications of rupture, cardiac tamponade, acute coronary ischemia, and branched arterial occlusion. Prolapse of the intimal flap into the distal ascending aorta and the aortic arch has been reported in cases of circumferential tear of the aortic intima.
1-4 We report a case of acute type A aortic dissection with intussusception of the intimal flap proximally into the aortic root and the left ventricular outflow tract, causing global myocardial ischemia.
A 75-year-old man had acute chest pain and shortness of breath. He was hypotensive, and the electrocardiogram disclosed global ST-segment depression in leads I, II, III, AVL, and AVF and precordial leads V2 to V6. Medical history included severe chronic renal insufficiency, coronary artery bypass grafting 10 years earlier, and repair of abdominal aortic aneurysm on 2 occasions 30 years and 7 years before the current presentation. A noncontrast computed tomographic (CT) scan of the chest and abdomen revealed extensive aneurysmal disease of the ascending and descending thoracic aorta with possible dissection of the descending and the remaining abdominal aorta. The patient was transferred to the cardiac catheterization laboratory, where multiple attempts at cannulation of the coronary ostia were unsuccessful. An aortic angiogram was inconclusive for dissection of the ascending aorta and failed to show the coronary arteries. Transesophageal echocardiography revealed an intimal flap in the root of the aorta close to the aortic valve prolapsing into the left ventricle in diastole (Figure 1). The aortic valve appeared intact. The patient was transferred to the operating room in cardiogenic shock and receiving high-dose inotropic support.
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Fig. 1. A, Aortic intimal flap in systole. B, Prolapsed intimal flap into the left ventricular outflow tract in diastole, covering the aortic valve. Open arrow, Aortic valve leaflet; filled arrow, intimal flap.
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Operative findings included a circumferential tear of the aortic intima in the midascending aorta at the level of old saphenous vein grafts. The intimal flap had totally prolapsed into the left ventricular outflow tract, covering the ostia of the left and right coronary arteries. During deep hypothermic circulatory arrest and retrograde cerebral perfusion, the dissection was repaired with an aortic valve conduit. Coronary artery bypass grafting was also performed.
Although infrequent, circumferential intimal tear of the ascending aorta can lead to intussusception of the intimal flap distally into the aortic arch in line with the direction of blood flow. 1-4 Proximal prolapse into the aortic root and left ventricular outflow tract is very unusual. The presentation in this patient might have been due to the presence of a saphenous vein graft suture line in the ascending aorta, keeping the distal flap from prolapsing, and to an extremely low cardiac output, despite high-dose inotropic support. Aortography was not diagnostic for ascending aortic dissection because the intimal flap had intussuscepted into the left ventricular outflow tract, and therefore there was absence of a false channel in the ascending aorta. We did not find any prior report on this complication in the English literature.
Contrast-enhanced spiral CT scanning of the chest is a fast, noninvasive, and sensitive test for the diagnosis of acute aortic dissection. 5 Contrast CT scan was not obtained in this patient because of severe renal insufficiency. The diagnosis was ultimately confirmed by means of transesophageal echocardiography. Transesophageal echocardiography can accurately establish the diagnosis of ascending aortic dissection by demonstrating a mobile flap or septum within the ascending aorta. 5,6 It is, however, invasive and requires a skillful technician and physician for performance and interpretation of the findings.
Acute dissection of the ascending aorta with prolapse of the intimal flap proximally into the aortic root and left ventricular outflow tract is an extremely uncommon and potentially lethal condition. In patients with prior coronary artery bypass grafting and symptoms suggestive of aortic dissection, appropriate diagnostic procedures should be used expeditiously to establish the diagnosis in the hope of providing a timely and lifesaving surgical operation for the patient.
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