Detection of the source of arterial emboli by transesophageal echocardiography: A case report

Transcription

1 Detection of the source of arterial emboli by transesophageal echocardiography: A case report Brian G. Rubin, MD, Benico Barzilai, MD, Brent T. Allen, MD Charles B. Anderson, MD, and Gregorio A. Sicard, MD, St. Louis, Mo. We report a case acute lower extremity ischemia caused by emboli in which the initial diagnostic evaluation, including standard aortoiliofemoral arteriography and routine transthoracic two-dimensional echocardiography, failed to reveal the offending source. Because of the strong clinical suspicion that the origin of the arterial occlusion was embolic, transesophageal echocardiography was performed. Transesophageal echocardiography demonstrated an aortic valvular lesion and cardiac surgery was performed on an emergency basis. The use of transesophageal echocardiography in evaluating the heart and thoracic aorta as a source of distal emboli is also discussed. (J VASC SURG 1992;15:573-7.) Arterial embolic disease is an increasingly recognized clinical problem) The last 5 decades have seen an increase in age of affected patients and a change in the cause of this syndrome. A large experience was initially accumulated in a younger group of patients with rheumatic heart disease, whereas more recently, atherosclerotic cardiac disease has been the predominant cause of cardioarterial emboli. 2~ The combined percentage of emboli of noncardiac origin or of unknown origin has remained constant at approximately 15%, with noncardiac causes being recognized with increasing frequency and "cryptogenic" emboli becoming rare. 6-1 Recognition of the importance of localizing the offending source and recent technologic advances such as transesophageal echocardiography (TEE), which permit thorough evaluation of cardiac and noncardiac sources of emboli are responsible for reducing the percentage of arterial emboli of unknown origin. We report a case of acute arterial ischemia in a patient who was evaluated with arteriography and taken to the operating room for immediate attention. At operation, the salient finding was the retrieval of white, organized appearing material from a normal arterial tree, consistent with embolization rather than From the Department of Medicine, Division of Cardiology (Dr, Barzilai), Washington University School of Medicine, and the Vascular Surgery Section, Department of Surgery (Drs. Rubin, Allen, Anderson, and Sicard), Washington University School of Medicine, St. Louis. Reprint requests: Brian G. Rubin, MD, The Jewish Hospital of St. Louis, Department of Surgery, 216 S. I~ngshighway, St. Louis, MO /4/32416 in situ thrombosis. Postoperative investigation revealed an unusual origin of the source of emboli, requiring subsequent additional surgical intervention. Recognition of the syndrome of arterial embolization mandates an aggressive approach to determining the point of origin. CASE REPORT G.G. is a 49-year-old white man who noted the acute onset of severe bilateral calf claudication and calf muscle tenderness. He had no history of cardiac arrhythmias. A cardiac catheterization performed 6 months before this admission for atypical chest pain revealed normal coronary anatomy, no valvular abnormalities, and a normal ventriculogram. At this admission, his physical examination was significant for a new 2/6 systolic murmur at the left sternal border, with a regular rate and rhythm. Vascular examination revealed bilaterally absent popliteal and pedal pulses. His admission electrocardiogram demonstrated sinus tachycardia. He underwent aortoiliofemoral arteriography, which demonstrated bilateral popliteal artery occlusions with poor collateralization and an essentially normal arterial tree otherwise (Fig. 1). Bilateral popliteai artery thrombectomies resulted in retrieval of organized white material from normal appearing arteries in both legs, consistent with bilateral emboli. After operation he had restoration of normal pulses in both lower extremities. Subsequent work-up included a standard transthoracic echocardiogram (TTE) which was interpreted as normal (Fig. 2). Because of the strong suspicion that the retrieved material originated from a proximal embolic source, he then underwent TEE, which demonstrated a mobile I cm 2 mass on the right cusp of the aortic valve (Fig. 3). The patient underwent aortic valve replacement on an emergency basis, and a soft, friable mass originating from an aortic valve leaflet was found. Pathologic evaluation of the 573

2 574 Rubin et al Journal of VASCULAR SURGERY Fig. 1. Angiogram of popliteal region demonstrates bilateral popliteal artery occlusions with poor collateralization. Above the level of occlusions arterial tree appears entirely normal. Fig. 2. Transthoracic echocardiographic (TEE) view of region of aortic valve. The quality of this image is typical of resolution obtained on TTE. The left ventricular outflow tract (LVOT) and aorta (AO) are labeled and aortic valve leaflets are indicated (solid white arrow). No valvular abnormalities were noted on this examination. popliteal artery specimen demonstrated organized thrombus as did the evaluation of the valve vegetation. The aortic valve specimen demonstrated evidence of dead valvular tissue, referred to as "necrobiotic valvulitis" (Fig. 4). DISCUSSION Arterial embolization is an increasingly frequent clinical problem. Often, after evaluating the patient's history, physical examination, and electrocardio-

3 Volume 15 Number 3 March 1992 Transesophageal echocardiography and arterial emboli 575 Fig. 3. Transesophageal echocardiographic view of the aortic valve. The left ventricular outflow tract (LVOT) and aorta (AO) are indicated. The aortic valve is open and a large echogenic mass (solid white arrow) hanging off the inside of the valve cusp in the middle of the aortic flow lumen is easily seen. This is the same area depicted in Fig. 2. Fig. 4. Histologic section of aortic valve. Fibrinoid necrosis and degeneration of portions of the valve are seen. Other sections demonstrated inflammatory granulation tissue with palisading histiocytes,.consistent with necrobiotic valvulitis. Special stains for fungal and bacterial microorganisms were negative. gram, the embolic source is readily apparent. Currently, cardiac sources of emboli comprise approximately 85% of all cases, with the primary abnormality being thrombus in the left atrium or left atrial appendage, valvular vegetations, or ventricular thrombus from a recent myocardial infarction or a ventricular aneurysm.ll As diagnostic modalities have improved, the percentage of emboli of unclear origin

4 576 Rubin et al. Journal of VASCULAR SURGERY has fallen, and some new or unusual embolic sources are being more commonly reported. Abbott et al.2 at the Massachusetts General Hospital reported that the embolic source could not be localized in only 5% of their patients. One recent, useful technique for evaluating the heart and thoracic aorta has been TEE. It is performed by use of an ultrasound transducer passed perorally into the midthoracic esophagus. From a vantage point directly behind the left atrium, and unencumbered by interposed intrathoracic and chest wall acoustic attenuation, TEE permits superb resolution of the entire heart and most of the thoracic aorta. 12 Although it is more commonly performed, standard transthoracic echocardiography (TTE) has several disadvantages; it may fail to adequately visualize the left atrium and has a reported overall sensitivity ranging from 30% to 88%. 13-'s In patients with left atrial thrombi from mitral stenosis, the thrombus is limited to the left atrial appendage in 40% of cases, '6 which is completely visualized in, at most, 20% patients when the standard transthoracic approach is used.'7 Additionally, a condition referred to as "spontaneous echocardiographic contrast" of the atrium is frequently seen on TEE. This phenomenon, only rarely recognized on TTE, appears to represent stagnant or slow atrial flow and is associated with an increased risk of arterial embolization.18,19 Transesophageal echocardiography also results in improved sensitivity of the detection of cardiac valxaalar vegetations. A recent report by Erbel et al.20 who used TEE as the "gold standard" demonstrated that TTE visualized all lesions greater than i cm seen by TEE. However, TTE recognized only 69% of TEE diagnosed vegetations from 6 to 10 mm and only 25% of TEE diagnosed vegetations of less than 5 ram. Since TEE uses a higher frequency transducer than TTE, resolution of delicate structures such as valve leaflets are markedly improved. Our patient with an aortic valxaalar lesion not seen on TTE, but readily apparent on TEE again demonstrates the sensitivity of this modality. Transesophageal echocardiography also can be used to visualize portions of the thoracic aorta) 2 Experience with TEE in the evaluation of aortic disease in patients with embolic syndromes is preliminary. However, Tunick and Kronzon 2~ demonstrated three cases of protruding or mobile atherosclerotic aortic plaque by TEE in patients with systemic embolization, and nine cases of aortic disease were reported by Hoffman et al?2 None of these lesions were demonstrable by TTE. Other less common causes of arterial embolization, including paradoxic emboli with right-to-left intracardiac shunts, are also readily diagnosable by TEE with a high degree of sensitivity. In a recent series of 479 patients with cerebral or peripheral emboli who underwent both TTE and TEE, potential sources ofemboli were detected in 176 (37%) by TTE versus 310 (65%) by TEE. 23 Transesophageal echocardiography is now a widely accepted, readily available technique with improved sensitivity and should be considered in patients in whom the suspicion of cardiac source of embolization is high despite a normal transthoracic echocardiogram, or as the initial imaging modality in patient with suspected arterial emboli from the thoracic aorta. REFERENCES 1. Elliotr JP Jr, Hageman JH, Szilagyi DE, et al. Arterial embolization: problems of source, multiplicity, recurrence and delayed treatment. Surgery 1980;88: Abbott WM, McCabe CC, Maloney KD, et al. Arterial embolism: a 44-year perspective. Am J Surg 1982; 143: Connett MC, Murray DH Jr, Wennecker WW. Peripheral arterial emboli. Am J Surg 1984;148: Fogarty TJ, Daily PO, Shumway NE, et al. Experience with balloon catheter technic for arterial embolectomy. Am J Surg 1971;122: Sheiner NM, Zeltzer J, Macintosh E. Arterial embolectomy in the modern era. Can J Surg 1982;25: Darling RC, Austen WG, Linton RR. Arterial embolism. Surg Gynecol Obstet 1967;124: Green RM, DeWeese JA, Rob CG. Arterial embolectomy before and after the Fogarty catheter. Surgery 1975;77: Hight DW, Tilney NL, Couch NP. Changing clinical trends in patients with peripheral arterial emboli. Surgery 1976;79: Warren R, Linton RR. The treatment of arterial embolism. N Engl J Med 1948;238: Warren 1K, Linton RR, Scannell JG. Arterial embolism: recent progress. Ann Surg 1954;140: Brewster DC, Chin AK, Fogarty TJ. Arterial thromboembollsm. In: Rutherford RB, ed. Vascular surgery. Philadelphia: WB Saunders, 1990: Seward JB, Khandheria BK, Oh JE, et al. Transesophageal echocardiography: technique, anatomic correlations, implementation, and clinical applications. Mayo Clin Proc 1988; 63: Schweizer P, Bardos F, Erbel R. Detection of left atrial thrombi by echocardiography. Br Heart J 1981;45: Wallach JB, Lukash L, Angrist AA. An interpretation of the incidence of mural thrombi in the left auricle and appendage with particular reference to mitral commissurotomy. Am Heart J 1953;45: Stratton JR. Common causes of cardiac emboli: left ventricular thrombi and atrial fibrillation. West J Med 1989;151: Kuecherer HF, Lee E, Schiller NB. Role of transesophageal echocardiography in diagnosis and management of cardiovascular disease. Cardiol Clin 1990;2:

5 Volume 15 Number 3 March 1992 Transesophageal echocardiography and arterial emboli Aschenberg W, Schlfiter M, Krenner P, et al. Transesophageal two-dimensional echocardiography for the detection of left atrial appendage thrombus. J Am Coil Cardiol 1986;7: Beppu S, Nimura Y, Sakakibara H, et al. Smoke-like echo in the left atrial cavity in mitral valve disease: its features and significance. J Am Coil Cardiol 1985;6: De Belder MA, Tourikis L, Leech G, et al. Spontaneous contrast echoes are markers of thromboembolic risk in patients with atrial fibrillation. Circulation 1989;80: Erbel R, Rohmann S, Drexler M, et al. Improved diagnostic value of echocardiography in patients with infective endocarditis by transesophageal approach: a prospective study. Eur Heart J 1988;9: Tunick PA, Kronzon I. Protruding atherosclerotic plaque in the aortic arch of patients with systemic embolization: a new finding seen by transesophageal echocardiography. Am Heart I 1990;120: Hoffmann T, Kasper W, Meinertz T, et al. Echocardiographic evaluation of patients with clinically suspected arterial emboli. Lancet 1990;336: Daniel WG, Angermann C, Engberding R, et al. Transesophageal echocardiography in patients with cerebral ischemic events and arterial embolism: a European multicenter study. Circulation 1989;80(suppl II):473. Submitted Feb. 21, 1991; accepted luly 12, BOUND VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the JOUV, NaL or VASCULAR SURGERY for 1992 are available to subscribers only. They may be purchased from the publisher at a cost of $65.00 for domestic, $85.55 for Canadian, and $81.00 for international subscribers for Vol. 15 (January to June) and Vol. 16 (July to December). Price includes shipping charges. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Subscription Services, Mosby-Year Book, Inc., Westline Industrial Drive, St. Louis, MO , USA. In the United States call toll free: (800) , ext In Missouri or foreign countries call: (314) Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNAL subscription.