Asian Cardiovasc Thorac Ann 1999;7:241-243
© 1999 Asia Publishing EXchange Pte Ltd
Aorto-Left Atrial Fistula Complicating Native Aortic Valve Endocarditis
Durgaprasad Rajasekhar, DM,
Padmanabhan Manoj, MCh,1,
Dronamraju Dilip, FRCS,1
Department of Cardiology
1 Department of Cardiothoracic Surgery
Sri Venkateswara Institute of Medical Sciences
Tirupati, Andhra Pradesh, India
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For reprint information contact: Durgaprasad Rajasekhar, DM Tel: 91 8574 51222 Ext. 2369 Fax: 91 8574 28803 Department of Cardiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, AP 517507, India.
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Abstract
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A 21-year-old male with native aortic valve Streptococcus viridans endocarditis was found to have an aorto-left atrial fistula by transthoracic echocardiography. He underwent successful fistula plication and aortic valve replacement.
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Introduction
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Infection of the aortic valve may extend into the annulus and the mitral-aortic intervalvular fibrosa, resulting in the formation of an aortic root abscess or a pseudoaneurysm in the region of the mitral-aortic intervalvular fibrosa.1,2 Such a pseudoaneurysm can rupture and cause an aorto-left atrial fistula.3 We describe the surgical treatment of this complication in a patient with aortic valve endocarditis.
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Case Report
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A 21-year-old male presented with fever, dyspnea, and palpitations of 4 weeks duration. On physical examination, he was febrile with a regular pulse of 86 beats•min–1, high volume, and blood pressure of 130/50 mm Hg. The jugular venous pressure was not raised. Cardiovascular system examination revealed a hyperdynamic apical beat, normal first and second heart sounds, and a long early diastolic murmur at the left second intercostal space. The lungs were clear and the abdomen was normal. Preliminary blood investigations detected moderate anemia (hemoglobin 81 g•L–1), polymorphonuclear leukocytosis, and a raised erythrocyte sedimentation rate (75 mm•h–1). A blood culture 2 weeks prior to hospitalization grew Streptococcus viridans. However, repeat cultures after admission were sterile. Chest radiography showed mild cardiomegaly, an electrocardiogram was within normal limits, and echocardiography revealed a mildly enlarged left ventricle with normal systolic function. A 4 x 8 mm vegetation was seen on the left coronary cusp. The mitral-aortic intervalvular fibrosa was echodense (Figure 1
). There was no vegetation on the mitral valve. Color flow Doppler imaging showed moderate aortic regurgi-tation but no mitral regurgitation. There was a color jet between the left aortic sinus and the left atrium (Figure 2), which was predominantly systolic. A diagnosis of aortic valve endocarditis with an aorta-to-left atrial fistula was made and the patient underwent aortic valve replacement with repair of the fistula.
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Figure 1. Parasternal long-axis echocardiogram showing the thickened and enlarged mitral-aortic intervalvular fibrosa.
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Figure 2. Color Doppler study showing a turbulent jet from the aortic posterior sinus to the left atrium, delineating the fistula.
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The heart was approached through a median sternotomy. Aortic cannulation was employed with two-stage jugular venous cannulation of the right atrium for cardiopulmonary bypass. Cardioplegia was instilled via direct coronary cannulation after an oblique aortotomy. No vegetation was seen on inspection of the aortic valve cusps but the annulus was mildly dilated. The left coronary sinus was dilated and a small ulcerated fistulous tract with a diameter of approximately l mm was seen opening into the left atrium. A fine probe was passed through the tract. The valve cusps were excised. The aortic end of the communication was closed with double-pledgeted 4/0 Prolene (Ethicon, Aurangabad, India) mattress sutures.
A 9-A Starr-Edwards prosthetic valve (Baxter Healthcare, Irvine, CA, USA) was sutured to the annulus. It was noted that the sewing ring fitted in neatly and completely covered the previously plicated opening of the fistula. Interrupted 2/0 Ethibond sutures (Ethicon Ltd, Edinburgh, Scotland, UK) were used to fix the valve. The aortotomy was closed in two layers with 4/0 Prolene. The patient came off cardiopulmonary bypass with inotropic support (dobutamine 5 µg•kg–1•min–1). He was extubated after 12 hours of elective ventilation. Pre-discharge echocardio-graphy confirmed closure of the fistula and good prosthetic valve function.
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Discussion
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The anterior mitral leaflet is in anatomical continuity with the aortic valve and the junctional zone between the two valves is formed by annular fibrous tissue termed the mitral-aortic intervalvular fibrosa.2 Infective endocarditis of the aortic valve can extend into the annulus and mitral-aortic intervalvular fibrosa, resulting in the formation of an aortic root abscess, pseudoaneurysm, and aortoatrial fistula.1 Such complications are more frequent in prosthetic valve endocarditis than in native valve endocarditis. The echocardiographic appearance of such aneurysms was first described by Bansal and colleagues.3 Transesophageal echocardiography is more sensitive than transthoracic echocardiography in the diagnosis of these complications of aortic valve endocarditis.1,4,5 In a series of 34 patients with aortic valve endocarditis, 2 (6%) had an aorta-to-left atrial communication detected by transesophageal echocardiography.1 In another series of 73 cases of aortic valve endocarditis with complications requiring surgery, only 2 patients (2.7%) had aorto-left atrial fistula.6 However, the fistula in our patient was easily detected by transthoracic echocardiography and color flow Doppler imaging.
Surgery is indicated even when the pseudoaneurysm is unruptured. Valve replacement in cases of aortic valve endocarditis with infection limited to the leaflets is associated with a low incidence of persistent infection. However, when the infectious process extends into the aortic annular wall or mitral-aortic intervalvular fibrosa, surgery is challenging.6,7 Several surgical techniques are available for repair and debridement of fibrous skeleton endocarditis. Any such surgical maneuver must be based on the 3-dimensional nature of the cardiac structures, achieve sufficient access to the site of infection, and cause minimal postoperative functional impairment.7 An individualized technique must be used, depending on the extent of the disease process. Surgery entails valve replacement and the use of an autograft or allograft to patch the surgical and infection-related defects. Konno's aortoventriculoplasty, originally described for enlargement of the aortic annulus and left ventricular outflow tract, has been used for debridement and repair of fibrous skeleton endocarditis.7 Gharagozloo and colleagues8 used anterior mitral leaflet tissue to repair an aortoatrial fistula. Our patient had no aortic root or wall abscess or destruction of the annulus. The fistulous tract was small, therefore, simple plication of the fistulous tract was sufficient and the sewing ring of the prosthetic valve strengthened the closures.
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References
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Karalas DG, Bansal RC, Hauek AJ, Ross JJ. Applegate PM, Jutzy KR et al. Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis: clinical and surgical implications. Circulation 1992;86:353–62.[Abstract/Free Full Text]
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Abstract
Introduction
