Early Operative Intervention in Aortic Bacterial Endocarditis

Early Operative Intervention in Aortic Bacterial Endocarditis Stewart M. Scott, M.D. "Early Operative Intervention in Aortic Bacterial Endocarditis" by Prager and associates (this issue, p 347) at Vanderbilt University provides additional evidence that surgery is effective treatment for acute bacterial endocarditis. Considerable progress has been made in the treatment of bacterial endocarditis, a disease that was almost uniformly fatal less than forty years ago. Penicillin and modern antibiotics have cured the majority of patients, but others have survived because operative intervention was undertaken expeditiously in the face of medical failure. Operative intervention for endocarditis implies the use of one or more prosthetic heart valves. The introduction of a foreign body such as a heart valve into a site of infection is contrary to usually accepted surgical principles. However, in 1964, Yeh and associates [l] demonstrated that a prosthetic heart valve could be used to correct the residual deformity of healed bacterial endocarditis on an aortic valve without reappearance of infection. More significantly, in 1965, Wallace and co-workers [21 and, in 1967, our own group [31 were faced with the care of patients who were in intractable heart failure and had active endocarditis on the aortic valve. Valve excision and replacement with a prosthesis were accomplished in each patient successfully and without recurrence of infection. Many subsequent reports have confirmed the efficacy of surgical intervention in eradicating bacterial endocarditis resistant to antibiotic therapy and for correcting heart failure resulting from destruction of heart valves and adjacent structures. Indeed, prosthetic valve replacement for acute bacterial endocarditis is now an accepted principle and an effective method of management. It is well known that at least 20% of patients with acute bacterial endocarditis treated mediFrom the Surgical Service, Veterans Adminstration Medical Center, Asheville, NC 28805.

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cally will not respond to antibiotics. The surgical mortality for this group of patients is high (25%) in contrast to that for patients with healed bacterial endocarditis or for patients undergoing elective aortic valve replacement (5%). Congestive heart failure and sepsis are the most frequent causes of early postoperative deaths in these patients. Optimal surgical results are obtained only if operation is performed before the onset of irreversible left ventricular dysfunction or sepsis. To accomplish this, a more aggressive approach as advocated by Stinson [41 is suggested. Any patient with endocarditis due to gram-positive cocci not highly sensitive to antibiotics, due to gramnegative bacteria, or due to fungi should be treated surgically. Operation should be performed urgently if heart failure is present or develops during the course of medical treatment. More than one arterial embolus or a single cerebral embolus of significant magnitude, persistent systemic toxicity after a week of antibiotics, persistently positive blood cultures after three days of appropriate antibiotics, evidence of spread of intracardiac infection, and progressive, severe renal dysfunction are also indications for urgent operation. When operation is undertaken early, simple valve replacement may be sufficient to eradicate the infection and to correct existing cardiac defects. Surgeons have a natural preference for prostheses that have proved to be most satisfactory in their own experience. There is evidence, however, that tissue valves rather than mechanical valves may be preferable at sites where active infection is present. On mechanical valves, infection occurs in tissue adjacent to the sewing ring. Abscess formation and dehiscence are therefore likely. On tissue valves, an infection usually occurs first on the valve leaflets.* Leaflet destruction results in valve failure, thus providing early evidence of an infected *Roberts WC: Personal communication, 1981.

OOO3-4975/81/100327-02$01.25 @ 1981 by The Society of Thoracic Surgeons

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prosthesis. It has been suggested that the sewing ring of the porcine prosthesis is more resistant to infection than the sewing ring of the mechanical valve because it has had prolonged fixation with glutaraldehyde [5]. While Prager and associates addressed only the problem of endocarditis on the natural aortic valve, it should be remembered that endocarditis occurring on a prosthetic heart valve also must be treated vigorously and that the same rules apply in selecting patients for operation. The operative mortality for patients with infected prostheses is about the same as the operative mortality for patients with active natural valve endocarditis. However, patients in whom infection develops on heart valve prostheses within two months of implantation

are at twice the risk of patients having late onset of prosthetic endocarditis.

References 1. Yeh TJ, Hall BP, Ellison RG: Surgical treatment of aortic valve perforation due to bacterial endocarditis: a report of six cases. Am Surg 30:766-769, 1964 2. Wallace AG, Young WG, Osterhout S: Treatment of acute bacterial endocarditis by valve excision and replacement. Circulation 31:450-453, 1965 3. Scott SM, Fish RG, Crutcher JC: Early surgical intervention for aortic insufficiency due to bacterial endocarditis. Ann Thorac Surg 3:158-161, 1967 4. Stinson EB: Surgical treatment of infective endocarditis. Prog Cardiovasc Dis 221455168, 1979 5. Mills NL: The role of surgical therapy for bacterial endocarditis. J La State Med SOC132:53-57, 1980