J Thorac Cardiovasc Surg 1996;111:681-683
© 1996 Mosby, Inc.
Echo-free perfused space after homograft replacement of aortic valve: A morphologic study
Paolo Masiello, MDa,
Generoso Mastrogiovanni, MDa,
Rosa Russo, MDb,
Pasquale Angrisani, MDb,
Giuseppe Di Benedetto, MDa
Divisions of Cardiac Surgerya and Pathologyb
Hospital S. Giovanni di Dio e Ruggi D'Aragona
Salerno, Italy
To the Editor:
We read with interest the letter from Carrel and coworkers
1 regarding a peculiar echocardiographic finding after homograft replacement of the aortic valve, which they called "echo-free perfused space."
We recently dealt with a similar case. A 64-year-old man with chronic hepatitis C came to our observation in very poor condition after acute endocarditis caused by Staphylococcus hominis. Twelve years previously, he had undergone aortic valve replacement for aortic stenosis with a 25 mm Medtronic Hall valve (Medtronic, Inc., Minneapolis, Minn.). Transesophageal echocardiography showed a normally functioning aortic valve prosthesis with a large paravalvular leak and an abscess cavity between the aortic wall and the left atrium. After medical treatment and improvement in clinical condition, the patient underwent déAaebridement of the abscess cavity to aortic prosthesis replacement with a fresh homograft 22 mm in size secured with interrupted 3-0 Tevdek sutures (Deknatel Division, Fall River, Mass.) reinforced with pledgets. Transesophageal echocardiography performed immediately after the operation showed a well-functioning aortic prosthesis with depressed left ventricular function. A small echo-free perfused space was evident between the aortic and the homograft walls, located at the site of the previous abscess. No significant hemodynamic problems, and particularly no obstruction of the left ventricular outflow tract, were found. Unfortunately, in the postoperative course the patient had intractable low-output syndrome and died of multiorgan failure 2 days later. An autopsy was performed and the aortic root was examined. Macroscopic examination showed a very small space, about 2 mm large, between the aortic wall and the homograft and a dehiscence of the proximal suture (Fig. 1). At microscopy, the space was filled with fibrin and there was no degeneration of the aortic or homograft walls. Fatty and muscular tissue from the external layer of the homograft was lying between it and the aortic wall of the host (Fig. 2).
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Fig. 1. A small space, about 2 mm, is visible between the aortic and homograft walls at macroscopic examination. Dehiscence of the suture is evident.
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Fig. 2. Microscopic study shows the space containing fibrin. No sign of degeneration of the walls is present. A mass of fatty and muscular tissue, coming from the homograft, is visible between the vessels.
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In 75% of their patients that had undergone aortic valve replacement with homograft, Carrel and associates 1 found a characteristic echographic finding, which they called "echo-free perfused space." They postulated that this space was related to a local dehiscence of the proximal suture line in an area of severe intrinsic structural failure. Results of the morphologic study of our patient at autopsy allow us to support the hypothesis that the echo-free perfused space is caused by a local dehiscence of the subcommissural proximal suture, rather than a structural failure of the aortic wall. No signs of necrosis of endomyocardial layer were found in our patient. Previous inflammation and consequent edema of the aortic wall could be a predisposing factor.
To our knowledge, no complications have been reported from the echo-free space; however, the dehiscence at the proximal suture site may represent an additional risk for rupture, embolus or infection. Consequently, use of additional stitching and fibrin glue may be indicated, and a closer follow-up is mandatory in the postoperative period.
References
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Carrel T, Pasic M, Oechslin E, Jenni R, Turina M. Echo-free perfused spaces: a current postoperative finding after homograft replacement of the aortic valve. J THORAC CARDIOVASC SURG 1994;108:786-7.[Free Full Text]
