Clinical and echocardiographic features of aorto-atrial fistulas

Karthik Ananthasubramaniam

doi:10.1186/1476-7120-3-1

Abstract

Aorto-atrial fistulas (AAF) are rare but important pathophysiologic conditions of the aorta and have varied presentations such as acute pulmonary edema, chronic heart failure and incidental detection of the fistula. A variety of mechanisms such as aortic dissection, endocarditis with pseudoaneurysm formation, post surgical scenarios or trauma may precipitate the fistula formation. With increasing survival of patients, particularly following complex aortic reconstructive surgeries and redo valve surgeries, recognition of this complication, its clinical features and echocardiographic diagnosis is important. Since physical exam in this condition may be misleading, echocardiography serves as the cornerstone for diagnosis. The case below illustrates aorto-left atrial fistula formation following redo aortic valve surgery with slowly progressive symptoms of heart failure. A brief review of the existing literature of this entity is presented including emphasis on echocardiographic diagnosis and treatment.

Highlights

A 66 year old male with history of rheumatic heart disease and aortic valve replacement (AVR) presented with progressive worsening fatigue, exertional dyspnea and paroxysmal nocturnal dyspnea
The echocardiographic findings mimicked changes which could be related to endocarditis, the absence of any obvious vegetations or prosthetic malfunction combined with lack of clinical and laboratory evidence of endocarditis favoured a more slowly progressive postoperative complication rather than an infectious process
In a previous report we have highlighted the fulminant course of prosthetic valve endocarditis due to Proteus mirabilis leading to aorto-right atrial fistula from rupture of a pseudoaneurysm secondary to prosthetic valve endocarditis [9]

Summary

Discussion

In a large collection of about 4000 cases of thoracic aortic aneurysms, Boyd first reported AAF as an incidental. This reveals the limitations of viewing a three dimensional structure such as the heart in a two dimensional fashion, a void which may be filled by 3-dimensional (3-D) echocardiography This case highlights the importance of intraoperative TEE in guiding valvular surgery identifying potential intraoperative cardiac complications, which can be corrected in the same setting. Since repeat sternotomy and cardiac surgery by itself carries a higher risk of perioperative complications, intraoperative pre and post pump TEE play an integral role in guiding the surgeons as to any new complications which may have risen during surgery This is more so in valve surgeries or aortic reconstruction surgery http://www.cardiovascularultrasound.com/content/3/1/1 where a real time 2-D TEE with color assessment pre and post pump provides important information regarding success of surgical intervention and new complications.

Conclusion

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