Cardiovascular Anesthesiology: Echo Rounds
A 60-yr-old female with a history of obesity, hypertension, and reactive airway disease presented with chest pain, back pain, and a recent syncopal event. The patient was in shock with evidence of cardiac tamponade. Computed tomography angiogram (CTA) showed “a hemorrhagic pericardial effusion and Type A intramural hematoma with linear defect of the anterior surface of the aortic root consistent with small dissection flap.” The patient was emergently taken to the operating room. Transesophageal echocardiogram (TEE) confirmed cardiac tamponade, good ventricular function, and mild aortic valvular insufficiency. A lesion was seen in aortic valve long-axis view at the anterior aspect of the sino-tubular junction (Fig. 1) (Video 1, see Supplemental Digital Content 1, http://links.lww.com/AA/A28, modified midesophageal aortic valve long-axis view in real-time shows a lesion [white arrow] at the anterior aspect of the sino-tubular junction, suggestive of dissection flap). In the aortic valve short-axis view, the same lesion appeared atheromatous with ragged edges and a central depression. It protruded into the aortic lumen and was located between the left and right coronary cusps (Fig. 2) (Video 2, see Supplemental Digital Content 2, http://links.lww.com/AA/A29, midesophageal aortic valve short-axis view in real-time demonstrates the lesion [white arrow] between the left and right coronary cusps; it is atheromatous with irregular borders). The aortic wall was minimally thickened and no dissection flap or false lumen was seen. Given the location of the atheromatous lesion in the aortic root and the accompanying cardiac tamponade, a provisional diagnosis of penetrating atherosclerotic ulcer with rupture into the pericardium was made. The surgical plan now changed to attempt a focal repair and avoid a more extensive aortic reconstruction. The pericardium was opened with prompt hemodynamic improvement. No other atheromatous lesions were palpated or seen by TEE in the ascending aorta. Cardiopulmonary bypass was initiated via femoral arterial and right atrial cannulae. A penetrating atherosclerotic ulcer surrounded by thrombus was identified between the origin of the left main coronary artery and the aortic valve commissure (Fig. 3). The ulcer was oversewn, the patient separated easily from cardiopulmonary bypass, and recovered fully.
Aortic lesions comprise a spectrum of pathology including dissection and two other lesser-known entities, intramural hematoma and penetrating atherosclerotic ulcer (Fig. 4). Intramural hematoma consists of blood within the aortic wall without intimal disruption. The presumed cause is vasa vasorum rupture. TEE criteria for aortic intramural hematoma are crescentic thickening of the aortic wall >0.7 cm with central displacement of intimal calcium and the absence of both a dissection flap and a Doppler flow signal in the aortic wall.1 Confirming intimal integrity is crucial. This is done by careful examination in multiple planes to exclude a dissection flap. The hematoma must be thoroughly assessed to ensure that there is no color flow Doppler signal. The presence of a color flow Doppler signal confirms a communication with the aorta and suggests that the presumed hematoma is actually the false lumen of an aortic dissection. Intimal calcium is important because when centrally displaced, aortic wall thickening is more easily appreciated. The absence of intimal calcium does not preclude the diagnosis of intramural hematoma. TEE provides excellent diagnostic accuracy with sensitivity and specificity of more than 90%.2 The natural history of intramural hematoma includes enlargement, aneurysm, or pseudoaneurysm formation and progression to dissection or rupture. A diagnostic conundrum occurs when trying to distinguish intramural hematoma from aortic dissection with false lumen thrombosis and no Doppler flow signal. In these cases, serial TEE examinations and other modalities, such as CTA or magnetic resonance imaging, are required. The classification of intramural hematoma is the same as aortic dissection with similar recommendations for surgical (Type A) or medical therapy (Type B). Medical therapy has been successfully used for Type A intramural hematoma.2 Echocardiographic features that argue in favor of surgery for Type A intramural hematoma are aortic diameter more than 5 cm and hematoma thickness more than 12 mm.3 As an option to medical therapy for Type B lesions, the role of endovascular stenting is not yet fully defined.
A penetrating atherosclerotic ulcer is “an atherosclerotic lesion with ulceration that penetrates the internal elastic lamina and allows hematoma formation within the medial layer of the aortic wall.”4 There are no defined TEE criteria for penetrating atherosclerotic ulcers. Usually a “crater like ulcer with jagged edges”5 is seen. At the site of the ulcer, there is aortic wall thickening from hematoma formation. Our patient had a “jagged” lesion with a small central depression that suggested ulceration. The full nature of this lesion could not be appreciated by CTA. What was reported as a “small dissection flap” was found at TEE examination to be a large ulcerating, atheromatous lesion. Penetrating atherosclerotic ulcers usually result in subadventitial hematoma. Thickening of the aortic wall from hematoma distinguishes penetrating atherosclerotic ulcers from protruding or mobile atheroma that do not breach the intima. Aortic wall thickening was minimal in our case. We believe that the transmural erosion of the ulcer into the pericardial sac prevented blood from significantly accumulating in the aortic wall because it was able to escape into the pericardium causing tamponade. We found only one reported case of penetrating atherosclerotic ulcer presenting with cardiac tamponade.6 The natural history of penetrating atherosclerotic ulcer can involve progression to dissection, frank rupture, or aneurysm. Intervention is generally recommended because of the increased likelihood of rupture when compared with aortic dissection or intramural hematoma. Surgery is usually required for lesions in the ascending aorta. Endovascular exclusion is an attractive option for a penetrating atherosclerotic ulcer in the descending aorta.
We present a case that demonstrates a rare cause for cardiac tamponade. Aortic dissection, intramural hematoma, and penetrating ulcer span a continuum with considerable overlap. The portability, speed, ease, and accuracy of TEE make it the best choice in diagnosing and guiding the management of these life-threatening conditions.
The authors thank Mr. David Alpern for his assistance in preparing the echocardiographic images.
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3. Kan CB, Chang JP. Optimal initial treatment and clinical outcome of type A aortic intramural hematoma: a clinical review. Eur J Cardiothorac Surg 2008;33:1002–6
4. Stanson AW, Kazmier FJ, Hollier LH, Edwards WD, Pairolero PC, Sheedy PF, Joyce JW, Johnson MC. Penetrating atherosclerotic ulcers of the thoracic aorta: natural history and clinicopathologic correlations. Ann Vasc Surg 1986;1:15–23
5. Sundt TM. Intramural hematoma and penetrating atherosclerotic ulcer of the aorta. Ann Thorac Surg 2007;83:S835–41
6. Yano K, Makino N, Hirayama H, Hatakenaka M, Matsui H, Soeda T, Hadama T. Penetrating atherosclerotic ulcer at the proximal aorta complicated with cardiac tamponade and aortic valve regurgitation. Jpn Circ J 1999;63:228–30
Clinician's Key Teaching Points
by Nikolaos J. Skubas, MD, and Roman M. Sniecinski, MD
- A penetrating atherosclerotic ulcer is a deep, irregularly shaped atheromatous lesion that extends past the intimal layer of the aorta toward the media and adventitial layers. Thrombus may be present on it usually protruding into the aortic lumen and, when long and mobile, can mimic an aortic dissection flap.
- When the penetrating atherosclerotic ulcer erodes beyond the intima, it often causes a hematoma and thickening of the aortic wall. It can erode through all of the aortic layers causing hemopericardium (and tamponade) or even frank rupture of the aorta.
- Echocardiographic examination in two orthogonal planes, mid (or upper) esophageal views at the level of aortic valve or ascending aorta in short and long-axis and color flow Doppler, are needed to differentiate it from artifact and other closely related aortic pathology, such as dissection (presence of an intimal flap) or intramural hematoma (thickened aortic wall not necessary associated with atheromas).