The surgical treatment of infective endocarditis

Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

[Evaluation of the benefit of early valve surgery in the treatment of infective endocarditis. Contribution of propensity analyses]

Early valve surgery for infective endocarditis, that is surgery performed during the course of antibiotic therapy, is widely used. However, this intervention has never been proven effective in any clinical trial. Five recently published observational studies, using propensity analysis, analyzed the relationship between surgery and mortality. But they gave conflicting results, mainly because of their methodological limitations. Thus, to date, there is no reliable estimation of early valvular surgery impact on mortality. In addition, this example allows for discussing the interest of propensity analyses and to emphasizing their limitations.

Early Surgery in Patients with Infective Endocarditis: A Propensity Score Analysis

BACKGROUND

An accurate assessment of the predictors of long-term mortality in patients with infective endocarditis is not possible using retrospective data because of inherent treatment biases and predictable imbalances in the distribution of prognostic factors. Largely because of these limitations, the role of surgery in long-term survival has not been adequately studied.

METHODS

Data were collected prospectively from 426 patients with infective endocarditis. Variables associated with surgery in patients who did not have intracardiac devices who had left-side-associated valvular infections were determined using multivariable analysis. Propensity scores were then assigned to each patient based on the likelihood of undergoing surgery. Using individual propensity scores, 51 patients who received medical and surgical treatment were matched with 51 patients who received medical treatment only.

RESULTS

The following factors were statistically associated with surgical therapy: age, transfer from an outside hospital, evidence of infective endocarditis on physical examination, the presence of infection with staphylococci, congestive heart failure, intracardiac abscess, and undergoing hemodialysis without a chronic catheter. After adjusting for surgical selection bias by propensity score matching, regression analysis of the matched cohorts revealed that surgery was associated with decreased mortality (hazard ratio, 0.27; 95% confidence interval, 0.13-0.55). A history of diabetes mellitus (hazard ratio, 4.81; 95% confidence interval, 2.41-9.62), the presence of chronic intravenous catheters at the beginning of the episode (hazard ratio, 2.65; 95% confidence interval, 1.31-5.33), and paravalvular complications (hazard ratio, 2.16; 95% confidence interval, 1.06-4.44) were independently associated with increased mortality.

CONCLUSIONS

Differences between clinical characteristics of patients with infective endocarditis who receive medical therapy versus patients who receive surgical and medical therapy are paramount. After controlling for inherent treatment selection bias and imbalances in prognostic factors using propensity score methodology, risk factors associated with increased long-term mortality included diabetes mellitus, the presence of a chronic catheter at the onset of infection, and paravalvular complications. In contrast, surgical therapy was associated with a significant long-term survival benefit.

Clinical features and predictors for mortality in patients with infective endocarditis at a university hospital in Taiwan from 1995 to 2003

The clinical features and microbiological characteristics of 315 patients with definite or possible infective endocarditis (IE) from January 1995 to December 2003 were evaluated. There were 187 males and 128 females with a mean age of 51 years (range, 1 month to 92 years). Ninety-three patients (30%) had a diagnosis of valvular heart disease and 24 (8%) had received prosthetic valve replacement. Blood culture was negative in 62 patients (20%). Staphylococci (91 patients, 32%), including methicillin-susceptible Staphylococcus aureus (15%), methicillin-resistant S. aureus (11%), and coagulase-negative staphylococci (6%), were the most commonly encountered pathogens followed by viridans group streptococci (77 patients, 24%). Eight patients (25%) had various neurological, renal, embolic, and cardiac complications. Patients with neurological complications [odds ratio (OR) 8.175, P<0.001], nosocomial IE (OR 6.661, P<0.001), underlying malignancy (OR 4.993, P<0.001), elevated serum creatinine level (OR 3.132, P=0.001), or elevated WBC count (>15000/mm3) (OR 2.537, P=0.007) were at significantly increased risk of mortality. This study found mortality from IE was associated with several factors, among which neurological complications were the most hazardous. Patients with more than one risk factor had poorer prognosis. These results suggest the need for more aggressive management in patients with IE when multiple risk factors for mortality are identified.

Long-term outcome of infective endocarditis: the impact of early surgical intervention

To determine the impact of early surgical intervention on long-term survival in patients with infective endocarditis (IE), charts of all patients who had IE from January 1987 through December 1996 were reviewed. A total of 252 patients with definite or possible IE were included. Forty-four patients (17.5%) had early surgery on median hospital day 2 (range, 0-30 days), and 208 patients (82.5%) received medical treatment alone. On multivariate analysis, several variables, including early surgical intervention, improved long-term survival rates (hazard ratio, 1.5; P=.03), mainly in patients with Staphylococcus aureus etiology (P=.04). When patients with prosthetic devices were excluded, the median duration of survival for patients who had early surgery was >150 months, compared with 61.5 months for patients in the medical group (P=.1). Early surgical intervention compared with medical therapy alone is associated with increased short- and long-term survival rates in patients with IE, primarily when IE is caused by S. aureus.

Operation for infective endocarditis: results after implantation of mechanical valves

BACKGROUND

Operation for acute endocarditis during the active phase violates a basic surgical rule not to implant a foreign body into an infective process, resulting in a high operative mortality and the risk of early recurrent endocarditis. Several investigators analyzing risk factors for perioperative mortality and morbidity presented strategies for more favorable outcomes, but most studies suffer from the drawback of heterogeneous populations observed over a long period of time.

METHODS

We present a prospective study on 138 patients operated on from March 1988 to March 1996. Patients were only included if the activity of the infection was proved by positive culture of the valve leaflets or by histologic staining. During the observation period, indication for operation, surgical approach, and postoperative antibiotic therapy were standardized as much as possible. After radical debridement of all parts of infected tissue, valve replacement was carried out with mechanical prostheses.

RESULTS

The early mortality was 11.5% overall. High New York Heart Association functional classification, advanced age, and staphylococcal disease were significant risk factors for early mortality. The site of infection, multiple valve involvement, and prosthetic valve endocarditis did not affect the outcome. Early recurrent endocarditis was recorded in only 3 patients of the entire series.

CONCLUSIONS

In case of acute infective endocarditis, valve replacement with mechanical prostheses is a safe procedure, if radical operation and aggressive postoperative antibiotic therapy are performed. For further improvements of the results, earlier operation is advisable in patients with rapidly progressive cardiac deterioration and in most cases of staphylococcal endocarditis.

A study of 47 bacteremic Staphylococcus aureus endocarditis cases: 23 with native valves treated surgically and 24 with prosthetic valves

A retrospective review of medical records from the Staphylococcus Laboratory, Copenhagen, 1982-1991, was carried out at the Department of Clinical Microbiology, Statens Serum Institut, 1994-1995, to investigate the clinical features and outcome of two subgroups of bacteremic Staphylococcus aureus endocarditis cases in non-drug addicts: patients with prosthetic valve endocarditis (PVE) and patients with native valve endocarditis treated surgically. Twenty-four cases of PVE were included. Six cases were early (within 60 days of valve implantation) and 18 were late. The overall in-hospital mortality was 42%. Surgical treatment resulted in a non-significantly lower mortality as compared with medical treatment alone (0% vs 50%, p = 0.19). Medical treatment of aortic and mitral valve endocarditis resulted in similar mortality rates (44% and 50%, respectively). Twenty-three cases of native valve infective endocarditis had the valve replaced surgically. The in-hospital mortality was 22%, which was significantly lower as compared with medical therapy (69%, p < 0.0001). The treatment changed significantly during the study period: 6 of 112 patients (5%) were treated surgically in the first half of the period (1982-1986) compared to 17 of 124 patients (14%) in the second half (1987-1991, p = 0.049). Severe congestive heart failure was the main indication for cardiac surgery in 21 patients. In conclusion, a shift towards a more aggressive surgical approach has taken place in the 10-year period. This development should be strengthened in the future as surgical intervention may improve survival in patients with infective endocarditis caused by S. aureus whether the infected valve is prosthetic or native.

Surgical treatment of endocarditis

Since early investigators first suggested that the treatment of endocarditis should include valve replacement for infections not readily controlled with medical therapy alone, the role of surgery has become expanded, yet refined, to improve the outcome of patients with this potentially fatal disease. Innovative surgical techniques have also been developed in an effort to improve the results of surgical treatment for complex sequelae of invasive infections. This article examines the current indications for surgical intervention, compares the various surgical options, and assesses the expected short-and long-term outcome after valve replacement for patients with native valve or prosthetic valve endocarditis.

Neurologic manifestations in Staphylococcus aureus endocarditis: a review of 260 bacteremic cases in nondrug addicts

PURPOSE

To investigate the neurologic manifestations of infective endocarditis caused by Staphylococcus aureus in a population of nondrug addicts with special emphasis on the clinical presentation, epidemiology, and mortality.

PATIENTS AND METHODS

During the period from 1982 to 1991 a total of 8,514 cases of bacteremia with S aureus were reported to the Staphylococcus Laboratory, Copenhagen, Denmark. The medical records of cases of suspected infective endocarditis were retrospectively reviewed and classified according to the new diagnostic criteria for endocarditis proposed by Durack.

RESULTS

A total of 260 cases from 63 hospitals fulfilled the diagnostic criteria. Overall, 91 patients (35%) experienced neurologic manifestations. Sixty-one presented with neurologic symptoms, whereas 30 patients developed neurologic complications at various intervals (median: 10 days) after the debut of the disease. The most frequent neurologic manifestation was unilateral hemiparesis, which occurred in 41 patients (45%). Forty-two percent of the females had neurologic manifestations compared to only 30% of the males (P = 0.06). Cases with native mitral valve infection had a significantly higher frequency of neurologic manifestations compared with all other valvular involvement (44% versus 29%, P = 0.02) but the frequency of neurologic complications was only nonsignificantly higher in those patients with native mitral valve infection than in those patients with native aortic valve infection (44% versus 31%, P = 0.10). Only two of the patients with tricuspid valve infection and none of those with congenital heart disorder experienced neurologic manifestations. A neurologic manifestation occurred in 22 (35%) of the 63 episodes in which vegetations were detected on the echocardiograms, compared with 17 (26%) of the 65 episodes without vegetations (P = 0.38). The mortality was 74% in patients with major neurologic manifestations and 56% in patients without neurologic manifestations (P = 0.008). In patients with neurologic complications the mortality was significantly higher among those treated with antibiotics alone as compared with those treated surgically (65 of 81, 80% versus 2 of 10, 20%; P = 0.0003).

CONCLUSIONS

In a population of nondrug addicts with infective endocarditis caused by S aureus the following main conclusions can be drawn: neurologic manifestations occur with a higher frequency in patients with native mitral valve infection. The presence of vegetations on echocardiograms is not a risk factor for developing neurologic complications but this conclusion is based on the results of transthoracic echocardiograms performed in only one half of the patients. The majority of the neurologic manifestations occur on presentation or shortly thereafter and the risk of recurrent embolism is low. Mortality is increased in patients with neurologic manifestations. A neurologic event per se may constitute an indication for surgical treatment.

Early and late survival after surgical treatment of culture-positive active endocarditis

OBJECTIVE

To describe a 30-year experience with surgically treated culture-positive active endocarditis.

DESIGN

We retrospectively reviewed the microbiologic, clinical, and operative findings and the survival data in 151 patients with culture-positive active endocarditis encountered between 1961 and 1991.

RESULTS

The mean age of the 110 male and 41 female patients was 49.8 years. Native valve endocarditis was present in 86 patients, and prosthetic valve endocarditis (PVE) was diagnosed in 65. The aortic valve was involved in 62% of patients, the mitral valve in 25%, and both valves in 10%. The operative mortality was 26%. The most important univariate determinants of mortality were an abscess at operation (P = 0.01) and renal failure (P = 0.03). A trend toward a higher mortality with PVE and staphylococcal infection was noted. For hospital survivors, the 5- and 10-year survival was 71% and 60%, respectively. Univariate determinants of an adverse long-term survival were annular abscess (P = 0.01), renal impairment (P = 0.01), heart failure (P = 0.02), and aortic valve involvement (P = 0.05). On multivariate analysis, the most important adverse determinants of long-term survival were heart failure (P = 0.02), renal impairment (P = 0.02), and PVE (P = 0.03). Thirty patients required a subsequent reoperation; of these, seven required a second and two a third operation. The most common reason for reoperation was periprosthetic regurgitation without infection (N = 19). Four operations were performed for recurrent endocarditis. At 5 and 10 years, the risk of reoperation was 23% and 36%, respectively.

CONCLUSION

Although surgical treatment of culture-positive active endocarditis is still associated with substantial mortality, the long-term outcome of hospital survivors is excellent. Subsequent reoperations for periprosthetic leak are common, but recurrent infection is uncommon.