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Background: In 2007, the American Heart Association recommended antibiotic prophylaxis for the prevention of infective endocarditis (IE) for only the highest-risk patients. Whether this change affected the use of antibiotic prophylaxis and the incidence of IE is unclear., Methods: IE-related hospitalizations were identified from 2002 to 2014 among all adults and those at high and moderate risk for IE, stratified by age. Prescriptions for antibiotic prophylaxis were obtained from the Ontario Drug Benefit database for adults ≥65 years of age. Outcomes were antibiotic prophylaxis prescription rates and incidence of IE-related hospitalization. Trends in patient and pathogen characteristics were analyzed. Time series analyses were performed with segmented regression and change-point analyses., Results: Prescriptions for antibiotic prophylaxis decreased substantially in the moderate-risk cohort after the guideline revision (mean quarterly prescriptions, 30 680 versus 17 954 [level change, -6,481; P=0.0004] per 1 million population) with a minimal, yet significant, decrease followed by a slow increase in the high-risk group. There were 7551 IE-related hospitalizations among 6884 adults ≥18 years of age. Among adults ≥65 years of age, the mean IE rate increased from 872 to 1385 and 229 to 283 per 1 million population at risk per quarter in the high- and moderate-risk groups, respectively. Change-point analyses indicated that this increase occurred in the second half of 2010 in adults ≥65 years of age, 3 years after the American Heart Association guideline revision. Staphylococcus aureus and streptococcal species accounted for 30.3% and 26.4% of all IE, with a decrease in streptococcal infections over time., Conclusions: Antibiotic prophylaxis decreased significantly in the moderate-risk group with minimal change in the high-risk group after the American Heart Association guideline revision in 2007. However, IE-related hospitalizations increased among both high- and moderate-risk patients 3 years after the revision. Our study provides support for the cessation of antibiotic prophylaxis in the moderate-risk population.

Background: Invasive dental treatments (IDTs) can yield temporary bacteremia and have therefore been considered a potential risk factor of infective endocarditis (IE). It is hypothesized that, through the trauma caused by IDTs, bacteria gain entry to the bloodstream and may attach to abnormal heart valves or damaged heart tissue, giving rise to IE. However, the association between IDTs and IE remains controversial. The aim of this study is to estimate the association between IDTs and IE., Methods: The data in this study were obtained from the Health Insurance Database in Taiwan. We selected 2 case-only study designs, case-crossover and self-controlled case series, to analyze the data. The advantage of these methods is that confounding factors that do not vary with time are adjusted for implicitly. In the case-crossover design, a conditional logistic regression model with exposure to IDTs was used to estimate the risks of IE following an IDT with 4, 8, 12, and 16 weeks delay, respectively. In the self-controlled case series design, a conditional Poisson regression model was used to estimate the risk of IE for the risk periods of 1 to 4, 5 to 8, 9 to 12, and 13 to 16 weeks following an IDT., Results: In total, 9120 and 8181 patients with IE were included in case-crossover design and self-controlled case series design, respectively. In the case-crossover design, 277 cases and 249 controls received IDTs during the exposure period, and the odds ratio was 1.12 (95% confidence interval, 0.94-1.34) for 4 weeks. In the self-controlled case series design, we observed that 407 IEs occurred during the first 4 weeks after IDTs, and the age-adjusted incidence rate ratio was 1.14 (95% confidence interval, 1.02-1.26) for 1 to 4 weeks after IDTs., Conclusions: In both study designs, we did not observe a clinically larger risk for IE in the short periods after IDTs. We also found no association between IDTs and IE among patients with a high risk of IE. Therefore, antibiotic prophylaxis for the prevention of IE is not required for the Taiwanese population.

Background: Because of the nephrotoxic effects of aminoglycosides, the Danish guidelines on infective endocarditis were changed in January 2007, reducing gentamicin treatment in enterococcal infective endocarditis from 4 to 6 weeks to only 2 weeks. In this pilot study, we compare outcomes in patients with Enterococcus faecalis infective endocarditis treated in the years before and after endorsement of these new recommendations., Methods and Results: A total of 84 consecutive patients admitted with definite left-sided E faecalis endocarditis in the period of 2002 to 2011 were enrolled. Forty-one patients were treated before and 43 patients were treated after January 1, 2007. There were no significant differences in baseline characteristics. At hospitalization, the 2 groups had similar estimated glomerular filtration rates of 66 and 75 mL/min (P=0.22). Patients treated before January 2007 received gentamicin for a significantly longer period (28 versus 14 days; P<0.001). The primary outcome, 1-year event-free survival, did not differ: 66% versus 69%, respectively (P=0.75). At discharge, the patients treated before 2007 had a lower estimated glomerular filtration rate (45 versus 66 mL/min; P=0.008) and a significantly greater decrease in estimated glomerular filtration rate (median, 11 versus 1 mL/min; P=0.009) compared with those treated after 2007., Conclusions: Our present pilot study suggests that the recommended 2-week treatment with gentamicin seems adequate and preferable in treating non-high-level aminoglycoside-resistant E faecalis infective endocarditis. The longer duration of gentamicin treatment is associated with worse renal function. Although the certainty of the clinical outcomes is limited by the sample size, outcomes appear to be no worse with the shorter treatment duration. Randomized, controlled studies are warranted to substantiate these results.

Background: The American Heart Association published updated guidelines for infective endocarditis (IE) prevention in 2007 that markedly restricted the use of antibiotic prophylaxis in certain at-risk patients undergoing dental and other invasive procedures. The incidence of IE caused by viridans group streptococci (VGS) in the United States after publication of the 2007 American Heart Association guidelines has not been reported., Methods and Results: We performed a population-based review of all definite or possible cases of VGS-IE using the Rochester Epidemiology Project of Olmsted County, Minnesota. Patient demographics and microbiological data were collected for all VGS-IE cases diagnosed from January 1, 1999, through December 31, 2010. We also examined the Nationwide Inpatient Sample hospital discharge database to determine the number of VGS-IE cases included between 1999 and 2009. We identified 22 cases with VGS-IE in Olmsted County over the 12-year study period. Rates of incidence (per 100 000 person-years) during time intervals of 1999-2002, 2003-2006, and 2007-2010 were 3.19 (95% confidence interval, 1.20-5.17), 2.48 (95% confidence interval, 0.85-4.10), and 0.77 (95% confidence interval, 0.00-1.64), respectively (P=0.061 from Poisson regression). The number of hospital discharges with a VGS-IE diagnosis in the Nationwide Inpatient Sample database during 1999-2002, 2003-2006, and 2007-2009 ranged between 15 318 to 15 938, 16 214 to 17 433, and 14 728 to 15 479, respectively., Conclusions: On the basis of data complete through 2010, there has been no perceivable increase in the incidence of VGS-IE in Olmsted County, Minnesota, since the publication of the 2007 American Heart Association endocarditis prevention guidelines.

Background: Infective endocarditis in children is rare, and most reports describe the experience in referral centers. The purpose of our study was to assess the characteristics of children with infective endocarditis in a large national sample., Methods and Results: We analyzed hospital discharge records with International Classification of Diseases, ninth revision, codes indicating infective endocarditis among admissions of patients <21 years of age in the Kids' Inpatient Databases 2000 and 2003; analyses for the 2 years were combined. In 1588 hospitalizations, the age distribution was bimodal, with peaks in infancy and late adolescence. The organism was coded in 632 admissions; Staphylococcus aureus was most common (57%), followed by the viridans group of streptococci (20%). Preexisting heart disease was present in 662 patients admitted (42%), among whom 81% had congenital heart disease, 8% had prosthetic valve endocarditis, and 5% had rheumatic heart disease. In-hospital mortality occurred in 84 patients (5%), 38 with preexisting heart disease. Death occurred in 12 of 25 patients (48%) with tetralogy of Fallot and pulmonary atresia, and 4 of 54 (8%) with prosthetic valve endocarditis. Among 46 deaths without preexisting heart disease, S aureus was the causative organism in 13 of 14 patients (93%) beyond infancy; among 32 infants who died, 10 (31%) were premature., Conclusions: In 2000 and 2003, we found a continuing shift in the epidemiology of pediatric infective endocarditis toward a higher proportion of children without preexisting heart disease. Risk factors for mortality included some forms of congenital heart disease and, among patients without preexisting heart disease, premature/neonatal age and S aureus as an etiologic agent.

Background: The purpose of this statement is to update the recommendations by the American Heart Association (AHA) for the prevention of infective endocarditis that were last published in 1997., Methods and Results: A writing group was appointed by the AHA for their expertise in prevention and treatment of infective endocarditis, with liaison members representing the American Dental Association, the Infectious Diseases Society of America, and the American Academy of Pediatrics. The writing group reviewed input from national and international experts on infective endocarditis. The recommendations in this document reflect analyses of relevant literature regarding procedure-related bacteremia and infective endocarditis, in vitro susceptibility data of the most common microorganisms that cause infective endocarditis, results of prophylactic studies in animal models of experimental endocarditis, and retrospective and prospective studies of prevention of infective endocarditis. MEDLINE database searches from 1950 to 2006 were done for English-language papers using the following search terms: endocarditis, infective endocarditis, prophylaxis, prevention, antibiotic, antimicrobial, pathogens, organisms, dental, gastrointestinal, genitourinary, streptococcus, enterococcus, staphylococcus, respiratory, dental surgery, pathogenesis, vaccine, immunization, and bacteremia. The reference lists of the identified papers were also searched. We also searched the AHA online library. The American College of Cardiology/AHA classification of recommendations and levels of evidence for practice guidelines were used. The paper was subsequently reviewed by outside experts not affiliated with the writing group and by the AHA Science Advisory and Coordinating Committee., Conclusions: The major changes in the updated recommendations include the following: (1) The Committee concluded that only an extremely small number of cases of infective endocarditis might be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100% effective. (2) Infective endocarditis prophylaxis for dental procedures is reasonable only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis. (3) For patients with these underlying cardiac conditions, prophylaxis is reasonable for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. (4) Prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of infective endocarditis. (5) Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure. These changes are intended to define more clearly when infective endocarditis prophylaxis is or is not recommended and to provide more uniform and consistent global recommendations.

Background: The risks of infective endocarditis (IE) associated with various conditions and procedures are poorly defined., Methods and Results: This was a population-based case-control study conducted in 54 Philadelphia, Pa-area hospitals from 1988 to 1990. Community-acquired IE cases unassociated with intravenous drug use were compared with matched community residents. Subjects were interviewed for risk factors. Diagnoses were confirmed by expert review of medical record abstracts with risk factor data removed. Cases were more likely than controls to suffer from prior severe kidney disease (adjusted OR [95% CI]=16.9 [1.5 to 193], P:=0.02) and diabetes mellitus (adjusted OR [95% CI]=2.7 [1.4 to 5.2], P:=0.004). Cases infected with skin flora had received intravenous fluids more often (adjusted OR [95% CI]=6.7 [1.1 to 41], P:=0.04) and had more often had a previous skin infection (adjusted OR [95% CI]=3.5 [0.7 to 17], P:=0.11). No association was seen with pulmonary, gastrointestinal, cardiac, or genitourinary procedures or with surgery. Edentulous patients had a lower risk of IE from dental flora than patients who had teeth but did not floss. Daily flossing was associated with a borderline decreased IE risk., Conclusions: Within the limits of the available sample size, the data showed that IE patients differ from people without IE with regard to certain important risk factors but not regarding recent procedures.

Background: The literature on infective endocarditis in hypertrophic cardiomyopathy (HCM) is virtually confined to case reports. Consequently, the risk of endocarditis in HCM remains undefined., Methods and Results: We assessed the occurrence of endocarditis in 810 HCM patients evaluated between 1970 and 1997. Endocarditis was diagnosed in 10 patients, 2 of whom were excluded from analysis of prevalence and incidence because they were referred for acute endocarditis. At first evaluation, echocardiographic features consistent with prior endocarditis were identified in 3 of 808 patients, a prevalence of 3.7 per 1000 patients (95% CI, 0.8 to 11). Of 681 patients who were followed, 5 developed endocarditis, an incidence of 1.4 per 1000 person-years (95% CI, 0.5 to 3.2); outflow obstruction was present in each of these 5 patients and was associated with the risk of endocarditis (P=0.006). In the 224 obstructive patients, incidence of endocarditis was 3.8 per 1000 person-years (95% CI, 1.6 to 8.9) and probability of endocarditis 4. 3% at 10 years. Left atrial size was also associated with the risk of endocarditis (P=0.007). In patients with both obstruction and atrial dilatation (>/=50 mm), incidence of endocarditis increased to 9.2 per 1000 person-years (95% CI, 2.5 to 23.5). Analysis of all 10 patients with endocarditis identified outflow obstruction in each and atrial dilatation in 7., Conclusions: Endocarditis in HCM is virtually confined to patients with outflow obstruction and is more common in those with both obstruction and atrial dilatation. These results indicate that antibiotic prophylaxis is required only in patients with obstructive HCM.

Background: Prosthetic aortic valve endocarditis is a serious complication that carries a high morbidity and mortality. Aortic homografts have been used in this setting, but long-term results are not available., Methods and Results: Over a 23-year period, 48 patients presented with infected aortic valve substitutes: 28 homografts, 15 mechanical, and 5 xenografts. Nineteen patients had emergency surgery, and the mean interval between the first and second operation was 5.9 years (range, 1 month to 22 years). In 28 patients, the preoperative New York Heart Association (NYHA) class was III or IV. Active endocarditis was present in 39 patients, and the microorganisms grown were Staphylococcus epidermidis (n = 13), Staphylococcus aureus (n = 6), Streptococcus viridans (n = 6), Streptococcus faecalis (n = 4), Candida albicans (n = 5), and Gram-negative spp (n = 2). Aortic root abscesses were found in 28 (58%) patients, and transesophageal echocardiography was 95% accurate in their localization. All patients received homograft aortic valves, 19 as root replacement and 29 using the freehand technique. There were four (8.3%) early deaths; poor left ventricular function and concomitant procedure were identified as risk factors. At a mean follow-up of 4 years (range, 2 months to 19 years) 95% of the patients were in NYHA class I or II without significant aortic regurgitation. The actuarial survival at 5 years was 97% (confidence limit, 84% to 100%), and freedom from endocarditis at 10 years was 97% (confidence limit, 84% to 100%). Multivariate analysis did not identify risk factors for these late events., Conclusions: Homograft aortic valves offer good early and long-term results in patients with infected aortic valve substitutes.

Background: All of the 2,401 patients with aortic stenosis (AS), pulmonary stenosis (PS), or ventricular septal defect (VSD) admitted to the First Natural History Study of Congenital Heart Defects between 1958 and 1965 were eligible for the Second Natural History Study. Most patients with severe defects were managed surgically, and most with mild defects were managed medically. Final examination in the first study was carried out 8 years after admission., Methods and Results: For AS, the incidence rate of bacterial endocarditis (BE) was 27.1 per 10,000 person-years. The incidence rate was 15.7 per 10,000 person-years for those managed medically and 40.9 per 10,000 person-years for those managed surgically. Most patients managed surgically had severe AS, and severity was more important to the risk of BE than the method of management. For PS, only one of the 592 patients with PS experienced BE. For VSD, the incidence rate of BE was 14.5 per 10,000 person-years. Size of the VSD was not associated with risk of BE. The risk of BE before closure of the VSD was more than twice that after surgery., Conclusions: The incidence rate of BE was nearly 35-fold the population-based rate. The increased incidence in patients with AS after valvotomy was a function of severity of the defect and not a function of surgery. Presence of aortic regurgitation in patients with AS did not increase the risk of developing BE. Surgical closure of VSD lowered the risk of BE.

A total of 688 patients received 808 Björk-Shiley prostheses during a 5 year span. Cumulative duration of follow-up totaled 1175.4 patient-years (1368 valve-years). Linearized rates in percent per patient-year for valve-related events (95% confidence limits) were: strut fracture, 0.5 (0.00 to 1.03); infective endocarditis, 0.94 (0.39 to 1.49); thromboembolism, 2.2 (1.37 to 3.052); valve impingement, 0.3 (0.00 to 0.77); and anticoagulant-related hemorrhage, 3.1 (2.15 to 4.14). No valve thrombosis occurred. Actuarial patient survival, including in-hospital mortality, was: aortic valve replacement, 79.8 +/- 3.4%; mitral valve replacement, 71.7 +/- 4.9%; double valve replacement, 59.8 +/- 7.5%. Incremental risk factors for death were age over 65 (p = .001), preoperative infective endocarditis (p = .04), and associated procedures (p = .0002). Although this prosthesis carries a low risk of infective endocarditis and thromboembolism, concern has been raised regarding its structural integrity.

Fifty-three (3.6%; actuarially 4.1% at 48 months) of 1465 consecutive in-hospital survivors of valve replacement from 1975 to July 1979 (aortic, mitral, or aortic and mitral, only one untraced) developed prosthetic valve endocarditis (PVE). Incremental risk factors for developing PVE were native valve endocarditis (p less than .0001), black race (p = .0001), mechanical prosthesis (vs bioprosthesis) (p = .005), male sex (p = .04), and longer cardiopulmonary bypass time (p = .09). In general, the hazard function for developing PVE was greatest at 3 weeks after valve replacement. Patients with native valve endocarditis had a tendency to develop PVE early after valve replacement, as did patients in whom mechanical prostheses were used. PVE associated with Staphylococcus epidermidis tended to appear within 6 months of valve replacement, whereas streptococcal PVE tended to appear later after valve replacement. PVE took an atypical form in some patients, but patients with possible PVE (n = 6) had the same findings as those with certain PVE (n = 47). In 11 patients bacteriologic confirmation of PVE was not obtained. The typical prosthetic and periprosthetic characteristics of PVE were present in 30 of the 40 cases in which observations were possible. PVE is a serious condition; 34 (64%) of our 53 patients died. Most deaths occurred within 3 months of the first evidence of PVE. Recovery of some patients is possible with appropriate medical and surgical treatment, but more intense preventive measures are indicated.

Twenty-six major cardiovascular centers participated in a cooperative study of all cases of infective endocarditis occurring during a single calendar year to obtain an overview of infective endocarditis. The study was designed to learn which patients appear to be at highest risk to develop this infection after palliative or reparative cardiovascular surgery. Of 278 patients developing infective endocarditis during the year at these medical centers, 63 (23%) had had previous cardiovascular surgery and 215 had not. Seventy percent of the 278 patients had recognized congenital or acquired heart disease before developing the infection. Rheumatic heart disease accounted for over half of the patients with underlying structural heart disease. A majority (55%) of the 63 patients who had been operated on before developing endocarditis had prosthetic valves inserted. Of those who did not require prosthetic valves, the majority had congenital heart disease with systemic artery-to-pulmonary artery shunts. Although these data were obtained from a selected group of patients, they confirm a significant risk of endocarditis in patients with prosthetic valves and suggest that in postoperative patients with non-valvular congenital heart disease, the highest risk appears to be in cyanotic patients with palliative pulmonary artery-to-systemic artery shunts.

Bacterial endocarditis developed in 24 patients during follow-up in the Natural History Study. It occurred significantly more often in patients with ventricular septal defect (1.5/1000 patient-years) and aortic stenosis (1.8/1000 patient-years) than in those with pulmonary stenosis (0.2/1000 patient-years). Complications, especially emboli and aortic regurgitation, occurred in 50% of the patients. Overall mortality was 25%. Incidence rates were significantly greater for males than for females and greater for patients over 20 years of age than for younger patients. Patients who had had ventricular septal defect treated surgically had a lower incidence of endocarditis than non-surgical patients, whereas surgery did not reduce the incidence in patients with aortic stenosis. The estimated risk of contracting bacterial endocarditis prior to 30 years of age in a patient with medically-treated ventricular septal defect is 9.7%; the risk estimate for surgical patients in 2.0%. Although data regarding the use of prophylactic antibiotics were not available for patients in the Natural History Study, these results certainly suggest that continued antibiotic prophylaxis for dental and certain surgical procedures is mandatory for patients with aortic stenosis, even after successful cardiac surgery. It is the authors opinion that prophylaxis is probably less necessary for patients who have pulmonary stenosis, whether surgically treated or not, and for patients with documented complete closure of VSD.

A retrospective review of 149 episodes of bacterial endocarditis (BE) in 141 patients under 25 years of age, at The Children's Hospital Medical Center from 1933 through June of 1972, demonstrates increasing survival and a distinct change in the frequency of underlying congenital heart disease and rheumatic heart disease (RHD). Certain forms of congenital heart disease such as tetralogy of Fallot, small ventricular septal defect, and aortic stenosis are at particular risk for BE. Following BE, patients with ventricular septal defect and tetralogy of Fallot have less morbidity and higher survival rates than children with aortic outflow lesions. over the entire time period, alpha Streptococcus is the most common pathogen and Staphylococcus aureus, second most frequent organism. Surgical correction in patients with congenital heart disease may offer the best form of prevention.

Thirteen patients with proven Q fever endocarditis and three additional patients with probable endocarditis are reviewed. The most helpful diagnostic test is the demonstration of a high complement fixing antibody titre to Phase 1 antigen of Coxiella burneti. The macroscopic pathology of the aortic valve is described and includes aneurysmal pockets in the aortic wall and valve annulus which are demonstrable angiographically. Evidence is presented that the infection may be controlled by prolonged tetracycline therapy and that this is accompanied by a falling antibody titre to Phase 1 antigen. Valve replacement is undertaken only for symptomatic and hemodynamic indications. The combined tetracycline therapy and valve replacement have produced a fall in titres with eradication of infection and palliation of the cardiac disability in all patients followed for long periods.