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Ann Thorac Surg 2001;71:100-103
© 2001 The Society of Thoracic Surgeons

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Original article: cardiovascular

Acute endocarditis treated with radical debridement and implantation of mechanical or stented bioprosthetic devices

^a Department of Cardio-Thoracic and Vascular Surgery, Odense University Hospital, Odense, Denmark

Accepted for publication August 24, 2000.

Address reprint requests to Dr Aagaard, Department of Cardio-Thoracic and Vascular Surgery, Odense University Hospital, DK-5000 Odense C, Denmark
e-mail: jan.aagaard{at}ouh.dk

	Abstract

Top Footnotes Abstract Introduction Patients and methods Results Comment References

 
Background. Operation for active infective endocarditis carries high mortality and morbidity rates, especially when the annulus is involved. Overall the literature favors the use of autograft and homograft valves because of better resistance to infection. In our clinic during the last 5 years we used an aggressive surgical approach to infective endocarditis in combination with implantation of mechanical or stented bioprosthetic devices.

Methods. From 1994 to 1999, 50 adults with aortic and/or mitral valve endocarditis underwent valve replacement. The median age of the 36 men and 14 women was 58 years (range, 17 to 78 years). All patients had active endocarditis at the time of operation. Native valve endocarditis was present in 48 patients and prosthetic valve endocarditis was present in 2 patients. The aortic valve was affected in 24 patients, the mitral valve in 21 patients, and both the aortic and mitral valves in 5 patients. Two of the patients with mitral endocarditis also had infection of the tricuspid valve. Annular destruction was present in 24 patients (48%). The patients were treated with radical excision of all infected tissue. The annular defects were closed, if possible, with direct sutures. Otherwise, a reconstruction was performed. Follow-up was 100% complete with a median follow-up period of 45 months (range, 6 to 66 months).

Results. The procedures were performed without lethal bleeding complications. Early mortality was 12% and the actuarial survival at follow-up was 80%. In none of the patients who died was death related to the prosthetic valve or recurrence of the endocarditis. Only 1 patient (2%) developed recurrence of the infective endocarditis and was reoperated with a Ross procedure. Three and a half years later the patient developed severe valve insufficiency of the autograft and was operated again with implantation of a mechanical device.

Conclusions. Native and prosthetic valve endocarditis can be treated successfully with aggressive surgical debridement and implantation of mechanical or stented bioprosthetic devices with a low risk of recurrent endocarditis.

	Introduction

Top Footnotes Abstract Introduction Patients and methods Results Comment References

 
The role of surgical treatment in the management of bacterial endocarditis is well established. Timely valve replacement during the course of the disease is expected to lead to an excellent functional outcome with a low prevalence of residual or recurrent infection. However, extension of the infectious process into the annular structures remains a major determinant of both the early and late results of surgical treatment of endocarditis. Varying degrees of annular involvement present a substantial challenge to the cardiac surgeon’s ingenuity in restoring the anatomic and functional integrity of the cardiac structures after removal of infected tissue. The surgical treatment of advanced endocarditis is constantly a matter of debate. Due to the nature of this disease, it has not been possible to conduct strict scientific studies on this subject to guide us in our choice of treatment for these patients, nor can this be expected in the future. In our clinic we believe radical debridement is a prerequisite to successful treatment. We have combined an aggressive surgical approach with the implantation of a mechanical or stented bioprosthetic device.

	Patients and methods

Top Footnotes Abstract Introduction Patients and methods Results Comment References

 
The present consecutive series represents all patients from January 1994 to September 1999 diagnosed with active infective endocarditis involving the aortic or the mitral valve or both who underwent operation. The hospital records and operative findings were reviewed retrospectively.

The median age of the 50 adults (36 men and 14 women) was 58 years (range, 17 to 78 years). All patients had active endocarditis at the time of operation and had been treated with antibiotics from a few days up to 1 month and in accordance with sensitivity tests in blood culture positive patients. Native valve endocarditis was present in 48 patients and prosthetic valve endocarditis in 2 patients. The aortic valve was affected in 24 patients, the mitral valve in 21 patients, and both the aortic and mitral valves in 5 patients. Two of the patients with mitral endocarditis also had infection of the tricuspid valve. Twenty-one patients (42%) were in New York Heart Association (NYHA) functional class IV and underwent urgent operation due to unstable hemodynamics. Six of the 21 patients were preoperatively on ventilator, and 2 of the 6 patients had commenced acute dialysis. The indications for operation in the remaining 29 patients were uncontrollable infection in 15 and embolism in 14 (cerebral, 9; peripheral, 5). Forty-one patients (82%) were preoperatively blood culture positive. The identified causative organisms are shown in Table 1. There was no difference in the incidence of positive blood cultures between patients with or without annular destruction.

The patients were treated with aggressive excision of all infected tissue, which means that the superficial layer of healthy tissue surrounding the infectious process was removed. The annular defects were closed, if possible, with direct sutures. Otherwise, the annulus was reconstructed. In 5 patients the outflow tract of the left ventricle was reconstructed with autologous pericardium and in another 4 patients with the insertion of a composite graft. In the 2 patients with partial separation of the left atrium from the ventricle the continuity was reestablished by direct sutures before implanting the device. A total of 55 valves were implanted: 43 Carbomedics [Sulzer Carbomedics, Austin, TX] (including 4 Carboseal composite grafts), 6 Mitroflow [Mitroflow, Vancouver, Canada], 3 Carpentier Edwards [Edwards Life Sciences, Irvine, CA], 2 St. Jude [St. Jude Medical, Minneapolis, MN], and 1 Björk Shiley Monostrut [Alliance Medical, Irvine, CA]. Concomitant coronary artery bypass grafting was performed in 2 patients. Mitral valve repair was not performed in any of the patients. The patients were treated postoperatively with intravenous antibiotics for 4 weeks.

Follow-up was obtained from a database containing the clinical visits of the patients. The follow-up was 100% complete, with a median follow-up period of 45 months (range, 6 to 66 months). Early mortality was defined as in-hospital death or death occurring within 30 days of operation. Actuarial survivorship was calculated by the Kaplan-Meier method.

	Results

Top Footnotes Abstract Introduction Patients and methods Results Comment References

 
Early mortality was 12% (6 of 50 patients). Preoperatively, these 6 patients were in a critical clinical condition. Three of the 6 patients could not be weaned from extracorporeal circulation. Three patients later died of multiorgan failure and without signs of recurrent endocarditis. Early reoperation was performed in 6 patients (13%) due to postoperative bleeding. Further, 1 patient with native aortic valve endocarditis was reoperated during the postoperative course due to a noninfectious iatrogenic defect in the anterior mitral leaflet. All reoperations were performed without further complications. Apart from the 3 patients who died of multiorgan failure, 3 patients needed temporary dialysis during the postoperative course. Recurrent endocarditis developed in 1 patient (2%). This patient was the only patient in whom a complete removal of all infected tissue was not described by the surgeon. Six weeks after the primary operation the patient underwent a Ross procedure. Three and a half years later the patient developed severe insufficiency of the autograft and was operated again with implantation of a mechanical valve. The patient is alive and doing well.

The late mortality was 9% (4 of 44 patients), and in none of these patients was death related to the prosthetic valve or the recurrence of endocarditis. A 25-year-old woman and drug addict died 5 months after operation in liver failure due to hepatitis. The second patient, a 70-year-old man with preoperative complicating diabetes and on hemodialysis, died 14 months after operation of coronary disease and myocardial infarction. Autopsy of a 67-year-old woman who died suddenly demonstrated coronary disease, a coronary thrombus, and myocardial infarction. The prosthetic valve was without change and functioning well. The fourth patient, a 25-year-old woman with preoperative severe lupus erythematosus disseminatus and on hemodialysis, died of bronchopneumonia 14 months after operation. The actuarial survival is presented in Figure 1. Forty of the 50 patients (80%) were alive at follow-up.

View larger version (8K): [in this window] [in a new window]   Fig 1. Postoperative survival in 50 patients treated for acute endocarditis.

	Comment

Top Footnotes Abstract Introduction Patients and methods Results Comment References

Operation for native or prosthetic valve endocarditis remains a formidable surgical challenge, with reported early mortality rates as high as 28% [3]. In another series of surgically treated native valve endocarditis the early mortality rate is around 8% [4, 5]. Prosthetic endocarditis is generally a more serious condition than native valve endocarditis, with a reported early mortality rate of 20% from the UK Heart Valve Registry [6]. As reconstruction of the valve is not a treatment of choice in patients with paravalvular destruction in whom the valve has to be replaced, one of the currently discussed questions is which replacement device meets the challenge of repairing a destroyed annulus while avoiding reoperation for early recurrent endocarditis? The suggestion of several authors to use homograft valves for replacement in aortic valve endocarditis sounds promising as the homograft valve is supposed to avoid several problems in these critically ill patients. The implantation may be technically easier because the biologic tissue is more flexible than a prosthetic device and so it can cope better with the problems of a destroyed aortic root [7, 8]. Perioperative mortality is considered by some authors to be lower after allograft replacement compared with prosthetic devices [9–11]. Concerning the question of whether the resistance of allografts toward recurrent or persisting endocarditis is higher, Haydock and coworkers [9] and McGiffin and colleagues [10] published two comparative clinical studies with large patient cohorts in 1992. Both demonstrated that allografts appear to have a lower immediate risk of recurrent endocarditis than mechanical valves or xenografts. Haydock and coworkers [9] reported an overall incidence of recurrent endocarditis of 10% for allografts versus 17% for xenografts or mechanical prostheses, and McGiffin and colleagues [10] reported incidences of 0% versus 17%, respectively. These studies, however, were not randomized and were carried out over a 20-year period, therefore differences in the outcome may not only be due to the replacement device but may also reflect differences in patient selection, surgical approach, and peroperative management during the observation period. In a later retrospective study by Niwaya and associates [12] the recurrence rate in patients with prosthetic aortic valve replacement was 12.5% (1 of 8 patients) versus 3% (2 of 60 patients) in the group of patients with a homograft or autograft for aortic valve replacement. This study was neither randomized nor prospective and only had a small number of patients in the prosthetic group. Patients who suffer from endocarditis involving both the aortic and mitral valves and in whom an aortic valve is replaced with a homograft or autograft will after all receive a prosthetic valve in the mitral position.

The supposed higher resistance of allografts to recurrent infection is attributed to the content of viable cells [13] which, in turn, seems to be dependent on the preservation technique. The best results were achieved with cryopreserved homografts, and the worst results were with cold, wet, stored, antibiotic-sterilized ones [14]. This, however, is one of the drawbacks of the method: cryopreserved allografts require an extraordinary expenditure for storage and stringent bacteriologic control. Therefore, this kind of allograft will hardly be available in most centers if a patient is admitted for urgent operation, which was the case in 42% of the patients in our study. Recent attention has focused on the use of autografts in the case of aortic valve endocarditis [12, 15, 16]. The Ross procedure is a demanding double procedure involving the implantation of an allograft and is not an option in an urgent situation. Another drawback of allograft valves is the need to reoperate many of these patients for graft failure. The incidence of tissue failure in allografts has decreased in recent years as new methods of preservation have been invented, but O’Brien and colleagues [17] reported 50% reoperations within 15 years after valve replacement and Baratt-Boyes and associates [18] described an actuarial freedom of only 42% from valve replacement 14 years after homograft implantation. The fact that patients with acute endocarditis are usually younger at the time of operation than patients with noninfectious acquired valve diseases [19] means that most patients in whom an aortic valve is replaced with an allograft will undergo reoperation for graft failure. Freedom from reoperation after Ross procedure (autograft or homograft) was reported by Elkins and colleagues [20] to be 89% at 5 years. As Blackstone and Kirklin [21] have pointed out, the risk after second valve procedures evidently increases and therefore every effort should be made to make the first valve procedure a lasting one.

We have, during the last 5 years, treated patients with active endocarditis and paravalvular destruction with implantation of a prosthetic device after debridement and reconstruction of the annulus. The majority of patients suffered from native valve endocarditis as prosthetic valve endocarditis is seldom seen in Denmark today. The rate of recurrent infection was very low in our study, with only 1 patient experiencing this complication (2%). Such a result can be achieved only if a very radical surgical approach is used [22–25]. Infected tissue must be removed thoroughly, even if large defects are created, because leaving infected tissue in situ always carries a high risk of recurrent endocarditis, regardless of the replacement device chosen [26, 27]. In fact, the patient who developed recurrent endocarditis in our study was the only patient in whom complete removal of all infected tissue was not described by the surgeon.

These guidelines may have a more serious impact on the outcome of these patients than the choice of the replacement device per se. Our data prove that, even in patients with acute infective endocarditis and annular abscess, replacement of the valve with a prosthetic device together with extensive debridement and the closure of abscess cavities leads to results as satisfactory as those reported after allograft replacement. Extensive debridement is an important factor for a low recurrence rate, and we find that a broad, tight, and secure fixation of the prosthetic device is equally important to avoid paravalvular leakage and recurrence. We have mainly been using the Sulzer Carbomedics (Austin, TX) prosthetic heart valve and find that the shape and the consistency of the sewing cuff fulfill these requirements for fixation very nicely.

The operations in our series were performed without lethal bleeding complications. This is in contrast to some previous reports [9–11] favoring the allograft. In the study by Niwaya and associates [12] using mainly homografts and autografts, 6 of 71 patients (8%) died perioperatively due to uncontrollable bleeding.

The present study has a relatively short follow-up period ranging from 6 to 66 months (median, 45 months), but there is unanimous agreement that events occurring months or years after operation for acute endocarditis are usually not related to the initial infection or to the surgical procedures performed. We conclude that a prosthetic device is still a good alternative to an allograft in patients undergoing urgent valve replacement for infective endocarditis. The procedure can be performed with a low operative mortality and a low rate of recurrence.

	Footnotes

Top Footnotes Abstract Introduction Patients and methods Results Comment References

 
This article has been supported, in part, by a de minimus contribution by Sulzer, Inc, Austin, Texas.

	References

Top Footnotes Abstract Introduction Patients and methods Results Comment References

 

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Jan Aagaard Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Aagaard, J. Articles by Andersen, P. V. Search for Related Content PubMed PubMed Citation Articles by Aagaard, J. Articles by Andersen, P. V. Related Collections Valve disease Related Article