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

Mitral Valve Repair and Replacement in Endocarditis: A Systematic Review of Literature

BACKGROUND

Several observational studies have suggested a superior survival after mitral valve repair compared with replacement in patients undergoing surgery for infective endocarditis. The objective of this study was to systematically review the rate of morbidity and mortality associated with mitral valve repair or replacement in infective endocarditis.

METHODS

A Medline search was conducted for literature and a systematic review of 24 studies, reporting prognosis of patients who underwent surgery for mitral valve endocarditis, was performed. Information on the patients, type of surgery, and follow-up was abstracted using standardized protocols.

RESULTS

A total of 470 patients (39%) underwent mitral valve repair and 724 patients (61%) underwent valve replacement. Lower in-hospital mortality (2.3% versus 14.4%, relative risk: 0.16, 95% confidence interval: 0.09 to 0.30, p < 0.0001) and long-term mortality (7.8% versus 40.5%, relative risk: 0.19, 95% confidence interval: 0.13 to 0.29, p < 0.0001) were observed among patients undergoing mitral valve repair compared with replacement. In addition, the rates of early reoperation (2.2% versus 12.7%, p < 0.0001), early cerebrovascular events (4.7% versus 11.5%, p = 0.045), late reoperation (4.7% versus 8.7%, p = 0.039), late recurrent endocarditis (1.8% versus 7.3%, p = 0.0013), and late cerebrovascular events (1.6% versus 24.4%, p < 0.0001) were significantly lower after mitral valve repair. Meta-regression analysis demonstrated that mitral valve repair over replacement was associated with a better early and late prognosis after surgery. Male sex and acute surgery were (nonsignificantly) predictive of worse early outcome.

CONCLUSIONS

A systematic review of literature showed that mitral valve repair is associated with good clinical in-hospital and long-term results among patients undergoing surgery for infective endocarditis.

Medical versus surgical management of Staphylococcus aureus prosthetic valve endocarditis

PURPOSE

The study's purpose was to identify prognostic factors associated with mortality in Staphylococcus aureus prosthetic valve endocarditis and to determine whether these factors influenced decisions to treat medically versus surgically. We also analyzed whether there was a subset of patients who were cured with medical therapy alone.

SUBJECTS AND METHODS

A retrospective review of patients with S aureus prosthetic valve endocarditis was performed. Demographic and clinical data were collected from existing medical records. Severity of illness was classified using American Society of Anesthesiologists (ASA) score. Impact of treatment on in-hospital mortality was assessed using multiple logistic regression analysis.

RESULTS

Fifty-five patients met the Duke criteria for definite S aureus prosthetic valve endocarditis. Twenty-three patients were treated medically, and 32 patients had surgical intervention. Overall mortality was 36% (28% in the surgical group and 48% in the medical group). ASA score IV (P < .001) and older age (P = .014) were significant risk factors of mortality. Patients with ASA score IV (P = .037) and multiple prosthetic valves (P = .013) were less likely to undergo surgery. Medically treated patients were older compared with those in the surgical group (median age 66 vs 55 years, P = .04). All 4 patients aged less than 50 years in the medically treated group survived.

CONCLUSION

Mortality was generally higher in the medically treated patients with S aureus prosthetic valve endocarditis. Multivariable analysis showed that ASA class IV and bioprosthetic valves were independent predictors of mortality. A subset of medically treated patients characterized by age less than 50 years, ASA score III, and without cardiac, central nervous system, or systemic complications were cured without surgical intervention.

Comparison of clinical and morphological characteristics of Staphylococcus aureus endocarditis with endocarditis caused by other pathogens

OBJECTIVES

To analyse clinical, echocardiographic, and prognostic characteristics of Staphylococcus aureus infective endocarditis (IE) compared with endocarditis caused by other pathogens.

DESIGN

Cohort study.

METHODS

194 consecutive patients with definite IE according to the Duke criteria prospectively examined by transthoracic and transoesophageal echocardiography were enrolled. Patients without identified microorganisms were excluded. The S aureus IE group (n = 61) was compared with the group with IE caused by other pathogens (n = 133).

RESULTS

Compared with IE caused by other pathogens, S aureus IE was characterised by severe co-morbidity, a shorter duration of symptoms before diagnosis, and a higher prevalence of right sided IE, cutaneous portal of entry, and history of renal failure. Severe sepsis, major neurological events, and multiple organ failure were more frequent during the acute phase in S aureus IE. In-hospital mortality (34% v 10%, p < 0.001) was higher in patients with S aureus IE and the 36 month actuarial survival rate was lower in S aureus IE than in IE caused by other pathogens (47% v 68%, p = 0.002). Multivariate analyses identified S aureus infection as a predictive factor for in-hospital mortality and for overall mortality.

CONCLUSIONS

S aureus IE compared with IE caused by other pathogens occurs in a more debilitated clinical setting and is characterised by a higher prevalence of severe sepsis, major neurological events, and multiple organ failure leading to higher mortality.

Staphylococcus aureus bacteremia and endocarditis

Staphylococcus aureus is a leading cause of bacteremia and endocarditis. Over the past several years, the frequency of S aureus bacteremia (SAB) has increased dramatically. This increasing frequency, coupled with increasing rates of antibiotic resistance, has renewed interest in this serious, common infection. S aureus is a unique pathogen because of its virulent properties, its protean manifestations, and its ability to cause endocarditis on architecturally normal cardiac valves. Although the possibility of underlying endocarditis arises in virtually every patient with SAB, only a minority of bacteremic patients will actually have cardiac involvement. Distinguishing patients with S aureus infective endocarditis (IE) from those with uncomplicated SAB is essential, but often difficult. In this review, the authors summarize recent changes in the epidemiology of SAB and IE, discuss the challenges in distinguishing SAB from IE, and discuss current trends in the management of patients with SAB and IE.

Infections of intracardiac devices

Intracardiac devices are increasingly used to correct hemodynamically dysfunctional valves and electrophysiologic abnormalities. These devices become infected at relatively low rates. Nevertheless, when these low rates are applied to widely used devices, significant numbers of infections result. Additionally, these infections have been associated with high degrees of morbidity and high mortality rates. This article reviews the epidemiology, microbiology, clinical presentation, and medical as well as surgical therapy of intracardiac device infections.

Staphylococcus aureus bacteremia and endocarditis

Staphylococcus aureus is a leading cause of bacteremia and endocarditis. Over the past several years, the frequency of S. aureus bacteremia (SAB) has increased dramatically. This increasing frequency, coupled with increasing rates of antibiotic resistance, has renewed interest in this serious, common infection. S. aureus is a unique pathogen because of its virulent properties, its protean manifestations, and its ability to cause endocarditis on architecturally normal cardiac valves. Although the possibility of underlying endocarditis arises in virtually every patient with SAB, only a minority of bacteremic patients will actually have cardiac involvement. Distinguishing patients with S. aureus infective endocarditis (IE) from those with uncomplicated SAB is essential, but often difficult. In this review, the authors summarize recent changes in the epidemiology of SAB and IE, discuss the challenges in distinguishing SAB from IE, and discuss current trends in the management of patients with SAB and IE.

Infections of intracardiac devices

Intracardiac devices are increasingly used to correct hemodynamically dysfunctional valves and electrophysiologic abnormalities. These devices become infected at relatively low rates. Nevertheless, when these low rates are applied to widely used devices, significant numbers of infections result. Additionally, these infections have been associated with high degrees of morbidity and high mortality rates. This article reviews the epidemiology, microbiology, clinical presentation, and medical as well as surgical therapy of intracardiac device infections.

Evidence of less severe aortic valve destruction after treatment of experimental staphylococcal endocarditis with vancomycin and dexamethasone

The beneficial effects of therapy combining an antibiotic and dexamethasone have been reported in human studies on meningitis and in experimental studies on septic arthritis, nephritis, and endophthalmitis. Since most patients with staphylococcal endocarditis need a combination of medical and surgical treatment, the purpose of this study was to determine whether the addition of dexamethasone to vancomycin has any beneficial effect regarding the degree of valve tissue damage or the course of experimental aortic valve endocarditis caused by a methicillin-resistant strain of Staphylococcus aureus. Rabbits with catheter-induced aortic valve vegetations were randomly assigned to a control group and to groups receiving dexamethasone (0.5 mg/kg of body weight, intravenously [i.v.], twice a day [b.i.d]), vancomycin (30 mg/kg, i.v., b.i.d), or dexamethasone plus vancomycin, for a total of 10 doses (two doses per day for 5 days). The severity of valve tissue damage was significantly less in groups receiving vancomycin plus dexamethasone compared with that of the group receiving vancomycin alone (P < 0.001). The severity of tissue damage was inversely correlated with the mean polymorphonuclear leukocyte number in valve tissue. No statistically significant differences were observed between the vancomycin-treated group and the vancomycin-plus-dexamethasone-treated group in survival, blood culture sterilization rate, or reduction of the microbial burden (in CFU per gram) in valvular tissue. In conclusion, treatment with a combination of vancomycin and dexamethasone for 5 days reduces the severity of valve tissue damage in experimental staphylococcal aortic valve endocarditis. These findings could have significant implications in the treatment of staphylococcal endocarditis and deserve further confirmation in clinical trials.