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J Thorac Cardiovasc Surg 2003;125:200-203
© 2003 The American Association for Thoracic Surgery
Brief Communications |
From the Department of Cardiovascular Surgery, Osaka City University Medical School, Osaka, Japan.
Received for publication Jan 23, 2002 Accepted for publication April 15, 2002. Address for reprints: Toshihiro Fukui, MD, Department of Cardiovascular Surgery, Osaka City University Medical School, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan (E-mail: tm-fukui{at}gem.hi-ho.ne.jp).
Aortic valve replacement in the presence of infectious endocarditis with an aortic annular abscess, aortic root destruction, and left ventricular-aortic discontinuity, remains a formidable surgical challenge. Early diagnosis and surgical intervention can be lifesaving.
1-3 Radical débridement of infected tissues and reconstruction of the left ventricular outflow tract are fundamental tenets of treatment. However, the choice of valve substitute remains one of the most contentious subjects in the management of this condition. Although several researchers 3-6 have reported success with homografts and autografts, prosthetic valve replacement remains the standard surgical approach. 7-9
Recently the porcine stentless bioprosthesis has gained favor as an aortic valve replacement because its hemodynamic performance is excellent and it has good midterm durability. 10-12 We have used this prosthesis in 5 patients with complex aortic root infection during the past 3 years, and that experience is the basis of this report.
Patients and methods (Table 1)
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One patient underwent surgery after inflammation had subsided in response to medical treatment. The other 4 patients were critically ill at the time of operation. The operation was postponed 2 weeks because of a hemorrhagic cerebral infarction in 1 case (case 4). In that case, the patient had been febrile for 1 week and had lost consciousness acutely while in the outpatient department. Cardiopulmonary resuscitation was started immediately, and catheterization, performed under percutaneous cardiopulmonary support and intra-aortic balloon pumping, revealed a stuck valve leaflet and massive aortic regurgitation. She was transferred to the operating room immediately.
Surgical management
A median sternotomy was created, and cardiopulmonary bypass was established with mild systemic hypothermia. The left ventricle was vented by cannulation through the right superior pulmonary vein. Cold blood cardioplegic solution was administered both antegrade and retrograde during aortic clamping. The surgical strategy was débridement of the abscess cavity and all friable tissue, reconstruction of the left ventricular outflow tract, and full root implantation with the Freestyle stentless valve (Medtronic, Inc, Minneapolis, Minn) with coronary reconstruction.
Results
Microbiology
The causative microorganism was isolated in 3 cases. Coagulase-negative Staphylococcus was cultured in 2 cases, and group B Streptococcus was cultured in another case. The infecting agent could not be identified in the final 2 cases.
Echocardiographic findings
Transesophageal echocardiography was performed preoperatively in all cases except for case 4, a patient whose unstable hemodynamic condition precluded examination. A pseudoaneurysm was detected in 2 of these cases (cases 1 and 2; Figure 1), and an aortic root abscess was demonstrated clearly in the other 2 (cases 3 and 5).
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In the other 3 cases, aortotomy revealed extensive inflammation of the entire aortic anulus, vegetations, and an annular abscess. Prosthetic valves were partially detached along the site of the abscess formation. In case 4, vegetations under the prosthetic valve had caused the valve leaflet to become stuck in the open position. In case 5, a para-annular abscess in the region of the noncoronary sinus communicated with the right atrium. A large vegetation attached to the orifice was removed, and the opening of the fistula was closed. Native valve and prosthetic valves were removed, followed by aggressive débridement. The abscess cavity in each patient was closed with a bovine pericardial patch, and the aortic root was reconstructed with the Freestyle valve. Inflow anastomosis sutures in the reconstructed anulus were placed with deep bites to attach the left ventricle to the patch. Thus the Freestyle valve was seated in the left ventricular outflow tract, and the closed abscess cavity was outside the valve itself. The coronary arteries were implanted as buttons to the side to the corresponding sinus of the bioprosthesis with a continuous 4-0 polypropylene suture. In case 3, a saphenous vein graft to the right coronary ostium was performed because a bicuspid valve made direct implantation of the coronary artery inadvisable.
The mean perfusion time was 366 minutes (range 239-520 minutes). The mean aortic crossclamp time was 199 min (range 155-246 minutes).
Operative results
There were no early or late deaths in this series. Low cardiac output necessitated postoperative intra-aortic balloon pump support in 1 case. In case 4, immediate sternal closure was precluded by low cardiac output at the time of surgery, and the sternum was closed uneventfully on the sixth postoperative day. Complete atrioventricular block, which did not necessitate pacemaker implantation, developed in 1 patient. No patients required reexploration for postoperative bleeding.
All patients received intravenous antibiotic therapy for at least for 4 weeks after the operation. Signs of inflammation subsided and disappeared completely, and all patients are alive and well without evidence of recurrent infection (Table 2
).
Discussion
Untreated infectious endocarditis with aortic annular abscess, aortic root destruction, and left ventricular-aortic discontinuity is invariably fatal. Immediate surgical intervention can be lifesaving, but the mortality rate after this heroic intervention can be as high 21%. 13 For patients with complex aortic root infection, simple replacement of the infected valve is inadequate treatment, and a more extensive operation is indicated.
Several innovative surgical techniques have been developed to manage aortic root infection, such as patch closure of the abscess and in situ valve replacement, 14 translocation of the aortic valve and saphenous vein bypass grafts to the coronary arteries, 15 and composite prosthesis and Dacron polyester fabric graft reconstruction of the aortic root. 16 Despite the success obtained with these methods, some researchers have reported the superiority of autograft and homograft valve replacement for complex aortic valve endocarditis. 3-6
Aortic homografts and autografts (Ross procedures) have been used for infectious endocarditis because these grafts mold well to the fragile infected aortic anulus, 3,17 offer excellent hemodynamic performance, 18 and are resistant to infection. Aortic homografts offer an attractive alternative to the implantation of prosthetic material. However, homografts are not always available and are particularly difficult to obtain in Japan. Further, the Ross operation is complicated, and it is not an option in urgent situations. 9 Recently, stentless porcine valves have been used to treat infectious endocarditis. 19,20 Santini and colleagues 19 reported a series of 10 cases of aortic valve infective endocarditis treated with porcine stentless valve (Biocor LTDA, Biocor Industriae e Pesquisa LtDa, Belo Horizonte, Brazil; Toronto SPV, St Jude Medical, Inc, St Paul, Minn).
Our surgical strategy for managing complex aortic endocarditis is full root replacement with the Freestyle stentless valve after extensive débridement of infected tissue, with closure of abscess as indicated. Patch closure of a periannular abscess and destroyed anulus permits obliteration of these cavities and facilitates reconstruction of the left ventricular outflow tract. The Freestyle stentless valve resembles an aortic homograft, and its handling qualities are similar to those of a homograft. We found it relatively easy to insert the Freestyle stentless valve into the left ventricular outflow tract, including the reconstructed aortic anulus. The technique that we used protected the débrided area by excluding it from exposure to systemic pressure. Radical débridement is absolutely essential to the eradication of infection. 7,21 Full root replacement with the Freestyle valve allows the surgeon greater confidence in performing radical débridement of all infected tissue, because prosthetic replacements for the structures integral to the left ventricular outflow tract are readily available. The Freestyle stentless valve with the full root replacement method offers the cardiac surgeon a new and powerful, option for treating complex aortic root infection. Our operative results were favorable, although the number of cases was small. Reinfection and valve dysfunction were not complications, and hemodynamic performance has been excellent. 22,23 Although long-term follow-up is necessary to determine its durability, the Freestyle stentless valve appears to be an excellent alternative to a homograft.
References
This article has been cited by other articles:
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  P. Stelzer Stentless Aortic Valve Replacement: Porcine and Pericardial Card. Surg. Adult, January 1, 2008; 3(2008): 915 - 934. [Full Text]
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 S. A. LeMaire and J. S. Coselli Options for managing infected ascending aortic grafts. J. Thorac. Cardiovasc. Surg., October 1, 2007; 134(4): 839 - 843. [Full Text] [PDF]
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 T. Shibata, Y. Sasaki, H. Hirai, T. Fukui, M. Hosono, and S. Suehiro Early surgery for hospital-acquired and community-acquired active infective endocarditis Interactive CardioVascular and Thoracic Surgery, June 1, 2007; 6(3): 354 - 357. [Abstract] [Full Text] [PDF]
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 D. G. Pennington The Impact of New Technology on Cardiothoracic Surgical Practice Ann. Thorac. Surg., January 1, 2006; 81(1): 10 - 18. [Full Text] [PDF]
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B. Mahesh, G. Angelini, M. Caputo, X. Y. Jin, and A. Bryan Prosthetic Valve Endocarditis Ann. Thorac. Surg., September 1, 2005; 80(3): 1151 - 1158. [Abstract] [Full Text] [PDF]
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