Ann Thorac Surg 2006;82:2282-2285
© 2006 The Society of Thoracic Surgeons
Case Reports
Perforation of the Valsalva Sinus After Implantation of Medtronic Freestyle Aortic Bioprosthesis
Nobuchika Ozaki, MD,
Yutaka Hino, MD,
Yuji Hanafusa, MD,
Teruo Yamashita, MD,
Kenji Okada, MD,
Takuro Tsukube, MD,
Yutaka Okita, MD*
Kobe University Graduate School of Medicine, Division of Cardiovascular, Thoracic, and Pediatric Surgery, Kobe, Japan
Accepted for publication April 24, 2006.
* Address correspondence to Dr Yutaka Okita, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan. (Email: yokita{at}med.kobe-u.ac.jp).
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Abstract
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We report on structural valve deterioration in patients with the Medtronic Freestyle aortic bioprosthesis (Medtronic, Inc, Minneapolis, MN), including spontaneous perforation of the Valsalva sinus. These occurred in four prosthesis in 3 patients using the modified subcoronary method or full root technique. One patient died of ruptured pseudoaneurysm and the others survived reoperation well. Careful follow-up is required after Freestyle bioprosthesis implantation.
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Introduction
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Only few reports have been published regarding structural valve deterioration (SVD) of the stentless aortic bioprosthesis. The Medtronic Freestyle aortic bioprosthesis (Medtronic, Inc, Minneapolis, MN) has provided excellent hemodynamics and improved surgical outcome including good survival and very low valve-related complication [1]. We report four cases of SVD in patients who had a Freestyle bioprosthesis.
From October 1999 through December 2002, 61 aortic valve operations including aortic root replacement with the Medtronic Freestyle valve (Medtronic, Inc) were performed at the Kobe University Hospital. Informed consent was obtained from all patients and institutional review board in our hospital demonstrated that approval was received and that consent was waived.
The pathology was aortic stenosis in 36 patients, aortic insufficiency (AI) in 21, and prosthetic valve failure in 4. Four valves were implanted in 3 patients who had SVD develop postoperatively.
The implant technique included the subcoronary technique in a patient and a full root technique in 3. With the subcoronary technique, the right and left sinuses of the Freestyle valve were incised and sutured to the native sinuses, respectively. The Freestyle valve noncoronary sinus was left intact and sutured to the ascending aorta. In the full root technique, the Freestyle valve was implanted with the whole system and the coronary buttons were anastomosed to the right and left coronary ostium correspondingly with 5-0 polypropylene suture. The first row suture was 4-0 polyester, and the sutures for the second row and aortic closure were 4-0 polypropylene.
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Patient 1
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A 63-year-old man presented with cardiopulmonary arrest and died. He had undergone aortic valve replacement using a 23-mm Freestyle valve with full root technique 51 months ago. Autopsy showed a large pseudoaneurysm with a hole 15 x 5 mm in diameter in the Freestyle valve noncoronary sinus, resulting in aortic rupture of the pseudoaneurysm to the right thorax. Pathologic findings showed that the defect in the noncoronary Valsalva sinus was at the transitional border between the elastic tissue and collagen fibers. There was no evidence of infection and suture line dehiscence.
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Patient 2
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A 62-year-old man was admitted because of severe AI and congestive heart failure. He had undergone aortic valve replacement for AI with a 21-mm Freestyle bioprosthesis using the subcoronary technique 20 months ago. At the second surgery, a 15-mm hole in the Freestyle valve noncoronary sinus that was left intact at the prior operation was noted (Fig 1). Severe AI was due to a right cusp tear and a 2-mm noncoronary cusp fenestration close to the right noncoronary commissure. He had a new 21-mm Freestyle valve with the full root technique. Pathologic findings showed that noncoronary Valsalva sinus hole was in the transitional zone between the elastic tissue and collagen fibers (Fig 2). There was no evidence of infection in pathologic examination. His postoperative course was uneventful.
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Fig 1. Operative findings showing a 15-mm hole in the Freestyle valve noncoronary sinus and a right cusp tear (right, intraoperative findings; left, specimen). (NCC = noncoronary cusp; RCC = right coronary cusp.)
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Fig 2. Pathologic findings showing noncoronary Valsalva sinus defect in the transitional zone between the elastic tissue and collagen fibers.
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Patients 3 and 4
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A 63-year-old woman with annulo-aortic ectasia complicating moderate AI and the ascending and arch aneurysm had a 25-mm Freestyle aortic valve replacement using full root fashion, the total aortic arch replacement with the 26-mm quadrifurcated graft. Seventeen months after the operation she had a pseudoaneurysm of the aortic root observed on the computed tomography (Fig 3). At the second surgery, two large holes (20 mm in diameter) were noted in the Freestyle valve left and noncoronary sinuses. She had aortic root replacement again with a 25-mm Freestyle valve using the full root technique. Histologic examination showed more or less the same findings as patients 1 and 2 in that the defects in the noncoronary and left Valsalva sinuses were located in the shift from the aortic elastic wall to the collagen fibers (Fig 4A). She had an uneventful recovery.
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Fig 3. Computed tomography showing the pseudoaneurysm of the aortic root (right, the lower part; left, the upper).
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Fig 4. Operative findings showing 20-mm holes in the Freestyle valve left and noncoronary sinuses in the 2nd (A) (right, intraoperative findings; left, specimen) and the 3rd operation (B) (right, specimen from inside; left, from outside). (LCC = left coronary cusp; NCC = noncoronary cusp.)
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One year later, an identical false aneurysm was noted and she underwent the third operation, which revealed the same findings, with large holes (20 mm in diameter) in the Freestyle valve left and noncoronary sinuses (Fig 4B). The modified Bentall procedure with a 23-mm Carpentier-Edwards (Edwards Lifesciences, Irvine, CA) pericardial valve and a 28-mm straight graft was performed. Consistently there was no evidence of infection, rejection, degeneration, and suture line trouble. She has been well for 25 months.
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Comment
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Very few cases of structural valve deterioration have ever been reported after the implantation of Freestyle aortic valves. Bach and colleagues [1] published 8-year data of 700 patients at eight centers and reported the SVD incidence to be 0.4% [1]. There were three cases of SVD, all occurring with the subcoronary technique. The main causes were cusp tears of Freestyle valve, and there was no case of perforation of the Freestyle valve wall as seen in the present cases. Recently one report regarding perforation of the Freestyle valve wall was published [2]. In their case, aortic wall perforation occurred in the left and noncoronary sinuses of Valsalva as seen in our cases. They suspected the cause to be careless manipulation of the Freestyle valve. Large holes in the noncoronary sinus spontaneously occurred in four of our cases, one by the subcoronary technique and three using the full root method. It is considerably suspected that small injury to the Freestyle aortic wall in the previous operation may be related to hazardous deterioration of the valve. However, we are very surprised to experience these cases, because the noncoronary sinus of Freestyle valve is usually not manipulated, not sutured, and left untouched, especially in the full root technique during operation.
Previous studies have demonstrated detailed anatomical, histologic, and dynamic research for the aortic root [3–5]. In the aortic root collagenous structure gradually replaces the aortic elastic tissue from the level of the sinotubular junction toward the annulus [3]. In the present cases, histologic findings showed that Valsalva sinus defects were in the transitional zone between the aortic elastic wall and annular collagen fibers. Histologic weakness may exist in the transitional zone, especially in the noncoronary sinus, where there is no coronary ostium. The greatest aortic annular circumferential and torsional deformation during the cardiac cycle occurred at the left annular sector and least occurred at the noncoronary sector. In contrast to large annular asymmetric deformations, the left, right, and noncoronary sinuses at the sinotubular junction contracted symmetrically [4]. This could increase the stress at the base of the noncoronary leaflet and the homologous sinus of Valsalva. In addition, the intrinsic anatomic weakness of this part can be explained by the embryologic origin of the aortic annulus. The right and left cusps originate respectively from the right superior and the left inferior truncoconal cushion, whereas the noncoronary cusp derives from the intercalated endocardial cushion [5]. These characteristics may lead to aortic sinus fatigue and eventual SVD.
In patient 2, using the modified subcoronary technique, there is some possibility that the tension by fluid collections between the noncoronary sinus of the Freestyle valve and the native aortic wall could have contributed to failure of the wall of the prosthesis at the location. Because the noncoronary sinus wall of the Freestyle valve was backed with the native aortic wall in the modified subcoronary technique to exert inner blood pressure on both the prosthetic and native aortic walls.
Another interesting thing is that one patient (patient 3) had the same findings of SVD twice (ie, large defects in the noncoronary and left coronary sinuses). Immunogenicity of the Freestyle bioprosthesis must be extinguished and no rejection for the Freestyle valve was histologically confirmed in these cases. Although the reason was uncertain, it might be associated with biocompatibility of glutaraldehyde-fixed valves in some special cases.
Since these cases, subsequent echocardiogram or computed tomography is now performed for patients with Freestyle aortic prosthesis at 6 months, 1 year, and then at 1-year intervals postoperatively.
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References
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- Bach DS, Kon ND, Dumesnil JG, Sintek CF, Doty DB. Eight-year results after aortic valve replacement with the Freestyle stentless bioprosthesis J Thorac Cardiovasc Surg 2004;127:1657-1663.[Abstract/Free Full Text]
- Kameda Y, Mizuguchi K, Kuwata T, Mori T, Taniguchi S. Aortopulmonary fistula due to perforation of the aortic wall of a Freestyle stentless valve Ann Thorac Surg 2004;78:1827-1829.[Abstract/Free Full Text]
- Sutton III JP, Ho SY, Anderson RH. The forgotten interleaflet triangles: a review of the surgical anatomy of the aortic valve Ann Thorac Surg 1995;59:419-427.[Abstract/Free Full Text]
- Dagum P, Green GR, Nistal FJ, et al. Deformational dynamics of the aortic root: modes and physiologic determinants Circulation 1999;100(Suppl):II-54-II-62.[Medline]
- Cicco GD, Lorusso R, Colli A, et al. Aortic valve periprosthetic leakage: anatomic observations and surgical results Ann Thorac Surg 2005;79:1480-1485.[Abstract/Free Full Text]
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Abstract
Introduction
