Ann Thorac Surg 2008;85:1791-1792. doi:10.1016/j.athoracsur.2007.10.056
© 2008 The Society of Thoracic Surgeons
Case Reports
Bioprosthetic Mitral Valve Implantation for Active Mitral Valve Endocarditis in Third Degree Thorax Burn
Maurice A. Smith, MD*,
David D. Yuh, MD
Department of Cardiac Surgery, Johns Hopkins Hospital, Baltimore, Maryland
Accepted for publication October 15, 2007.
* Address correspondence to Dr Smith, Johns Hopkins Hospital, Department of Cardiac Surgery, 600 N Wolfe St, 618 Blalock, Baltimore, MD 21287-4618 (Email: msmit179{at}jhmi.edu).
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Abstract
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Infective endocarditis remains a devastating complication in the thermally injured patient. The treatment of infective endocarditis is primarily medical, but surgical intervention is often mandatory when various complications arise. We believe that this is the first reported case of mitral valve replacement in a patient with third degree burns to the thorax. We also discuss surgical indications and treatment options in this clinical setting.
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Introduction
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Endocarditis is a well-described complication of the thermally injured patient with an incidence of 0.6% to 1.5% reported in previous series. The mortality of infective endocarditis remains relatively high at 20%, but for the thermally injured patient the mortality has been reported as high as 95%. Burn patients are predisposed to endocarditis due to the high rate of bacteremia, a predisposition to forming fibrin platelet vegetations on the endocardium and repetitive trauma to the endocardium from indwelling venous catheters [1].
Bacterial endocarditis is a disease initially treated with parental antibiotic therapies, yet surgical intervention is mandatory when various complications arise. We present a case of active mitral valve endocarditis with embolic complication and large vegetation in the setting of a 90% total body surface area burns including the thorax. This is a unique presentation in that there have only been 3 reported cases of valvular replacements in burn patients (ie, 1 in Saudi Arabia, 1 in Belgium, and 1 in the United States). We believe this is the first reported case of mitral valve replacement performed in a patient with third degree burns to the thorax.
A 15-year-old healthy boy was severely burned in a gasoline fire with 90% total body surface area burns. He was taken to the operating room for escharatomy of bilateral upper and lower extremities. He required multiple replacements of allografts to both upper extremities, and his back was tangentially excised and allografted on day 13 of admission. His course was complicated on hospital day 16 by line sepsis with methicillin-resistant Staphylococcus aureus bacteremia. He remained febrile despite appropriate antibiotic coverage. On hospital day 20, he became acutely comatose with a disconjugate gaze. A head computed tomographic scan showed hydrocephalus with multiple periventricular infarcts and Osler nodes and Janeway lesions developed as seen on physical examination. A transthoracic echocardiograph showed a 23-mm serpiginous mobile vegetation on the posterior mitral valve leaflet with a 16-mm subvalvular extension and a mild central jet of mitral regurgitation, but there was no evidence of stenosis or mitral prolapse. On hospital day 21 the patient underwent excision and reallografting of the chest and abdomen.
Given the patient's youth and potential for recovery, he underwent mitral valve replacement on hospital day 22. The skin allograft over the chest was removed and the underlying soft tissue was scrubbed with a 4% chlorhexidine brush. The skin was then prepped with Chlora-Prep (Medi-Flex, Leawood, KS), which is 2% chlorhexidine and 70% isopropyl alcohol, and was draped with 3M Ioban Steri-Drape (3M Medical, St. Paul, MN). Through a median sternotomy, cardiopulmonary bypass was initiated in the standard fashion, and the mitral valve was accessed through a standard transverse left atriotomy. On inspection, necrotic material replaced the P2 and P3 mitral leaflet scallops extending up to but not into the posterior mitral annulus. The necrotic tissue was debrided and the anterior leaflet was excised as well. A 27-mm St. Jude BioCor (St. Jude Medical, St. Paul, MN) mitral bioprosthetic was implanted. A 32-French mediastinal chest tube was placed as was a 24-French left pleural Blake drain (Ethicon Inc, Sommerville, NJ). The sternum was reapproximated and the pectoralis fascia was closed with a running 2-0 Vicryl suture (Ethicon Inc) and the remaining dermis was closed with a 4-0 Caprosyn (Medent Barr Agencies, New Zealand). Pacing wires and chest tubes were secured in the normal fashion and he was dressed with Xeroform gauze (Kendall Healthcare, Indianapolis, IN). At this point, new allograft dressing was placed. Cultures confirmed that the native valve was infected with methicillin-resistant S. aureus. At his 2-month follow-up, the patient continues to be free from infection.
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Comment
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Due to the relatively high surgical mortality with active endocarditis, the American Heart Association has developed guidelines for surgical treatment. Class I recommendations, elaborating conditions for which there is general agreement that surgery is useful and effective, include fungal infective endocarditis, infection with aggressive antibiotic resistant bacteria, left-sided infective endocarditis caused by gram negative bacteria, persistent infection with positive blood cultures after 1 week of antibiotic therapy, and one or more embolic events during the first 2 weeks of antimicrobial therapy. Echocardiographic findings supporting surgical therapy include evidence of valve dehiscence, perforation, ruptured fistula, large perivalvular abscesses, and obstructive vegetations [2].
The surgical treatments of active infective endocarditis traditionally include mitral valve repair techniques and mitral valve replacement with mechanical or bioprosthetic valves. There are several published series on mitral valve repair for active endocarditis. Iung and colleagues [3] reviewed 32 cases of active mitral valve endocarditis of which 28 resulted in successful valve repair and Muehrcke and colleagues [4] reviewed 58 cases of active endocarditis of which 26 were successfully repaired. These results led to several general conclusions. Patients with vegetations on the anterior and posterior leaflets and those with previous mitral valve repairs were likely to require replacement. Near bileaflet obstruction necessitated repair whereas other abnormalities, such as annular abscess and chordal rupture, did not necessarily preclude repair. According to an analysis of more than 6,000 patients with infective endocarditis undergoing mitral valve surgery at more than 661 centers, the mortality rate was 10.6% for mitral valve repair and 15.7% for replacement. The review also reported a 5-year freedom from infection rate of 96% for valve repair compared with 83% for valve replacement, and a 10-year event-free rate of 80% for repair versus 46% for replacement [5]. Due to the selection bias that more aggressive disease was treated with valve replacement, no conclusions could be drawn on which procedure was truly preferable. However, these results suggest that mitral valve repair is a feasible option in certain circumstances.
The issue of prosthetic versus mechanical valve use in mitral valve replacement for acute infective endocarditis is less clear as the published evidence is conflicting. Cortina and associates [6] reported a higher incidence of recurrent infection in patients receiving mechanical valves. Sweeney and coworkers [7] found bioprosthetic valves were more likely to become infected, and Mullany and colleagues [8] showed no aspect of early or late outcomes that were influenced by the type of prosthesis implanted. Although this evidence does not provide firm guidelines, it is generally accepted that mechanical valves should be used in younger patients and prosthetic valves in patients greater than 70 years of age [2].
Several factors went into the decision for surgical treatment of this patient's active infective endocarditis. The patient had positive blood cultures despite 1 week of directed parenteral antibiotics, and he suffered embolic complication during the first 2 weeks of antimicrobial therapy, both of which are class I American Heart Association indications for surgical treatment. Although vegetation size alone has rarely been used as an indication for surgery, meta-analysis suggested the risk of systemic embolization is increased in patients with vegetations less than 10 mm in diameter (33% vs 19%) [2]. Surgery was advocated because it was believed that this young patient had a favorable chance of neurologic recovery if further emboli were prevented. All of these factors led to the decision that surgical treatment was the best option for this patient, despite the high risk for prosthetic endocarditis, given that the operation required transversing infected burn tissues. Our decision to use a bioprosthetic valve was largely based on the need to limit anticoagulation in the face of recurrent skin grafting operations that would be needed in the future. Through careful planning and close collaboration with our plastic surgical colleagues, we report a successful case of mitral valve replacement in a patient with third degree burns to the thorax.
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References
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- Apple J, Hunt J, Wait M, Purdue G. Delayed presentation of aortic valve endocarditis in patients with thermal injury J Trauma 2002;52:406-409.[Medline]
- Yamaguchi H, Eishi K. Surgical treatment of active infective mitral valve endocarditis Ann Thorac Cardiovasc Surg 2007;13:150-155.[Medline]
- Contemporary results of mitral valve repair for infective endocarditis J Am Coll Cardiol 2004;43:386-392.[Abstract/Free Full Text]
- Muehrcke DD, Cosgrove DM, Lytle BW, et al. Is there an advantage to repairing infected mitral valves? Ann Thorac Surg 1997;63:1718-1724.[Abstract/Free Full Text]
- Ruttman E, Legit C, Poelzl G, et al. Mitral valve repair provides improved outcome over replacement in active infective endocarditis J Thorac Cardiovasc Surg 2005;130:76.
- Cortina JM, Martinella J, Artiz V, Fraile J, Serrano S, Rabogo G. Surgical treatment of active prosthetic valve endocarditis: results in 66 patients Thorac Cardiovasc Surg 1987;35:209-214.[Medline]
- Sweeney MS, Reul GJ, Coley DA, et al. Comparison of bioprosthetic and mechanical valve replacement for active endocarditis J Thorac Cardiovasc Surg 1985;90:676-680.[Abstract]
- Mullany CJ, Chua HV, Schaff HV. Early and late outcome after surgical treatment of culture positive active endocarditis Mayo Clinic Proc 1995;70:517-525.[Abstract]
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Abstract
Introduction
