Risk Factors of Prosthetic Valve Endocarditis: A Case-Control Study

Healthcare exposures and associated risk of endocarditis after open-heart cardiac valve surgery

BACKGROUND

Infective endocarditis (IE) following cardiac valve surgery is associated with high morbidity and mortality. Data on the impact of iatrogenic healthcare exposures on this risk are sparse. This study aimed to investigate risk factors including healthcare exposures for post open-heart cardiac valve surgery endocarditis (PVE).

METHODS

In this population-linkage cohort study, 23,720 patients who had their first cardiac valve surgery between 2001 and 2017 were identified from an Australian state-wide hospital-admission database and followed-up to 31 December 2018. Risk factors for PVE were identified from multivariable Cox regression analysis and verified using a case-crossover design sensitivity analysis.

RESULTS

In 23,720 study participants (median age 73, 63% male), the cumulative incidence of PVE 15 years after cardiac valve surgery was 7.8% (95% CI 7.3-8.3%). Thirty-seven percent of PVE was healthcare-associated, which included red cell transfusions (16% of healthcare exposures) and coronary angiograms (7%). The risk of PVE was elevated for 90 days after red cell transfusion (HR = 3.4, 95% CI 2.1-5.4), coronary angiogram (HR = 4.0, 95% CI 2.3-7.0), and healthcare exposures in general (HR = 4.0, 95% CI 3.3-4.8) (all p < 0.001). Sensitivity analysis confirmed red cell transfusion (odds ratio [OR] = 3.9, 95% CI 1.8-8.1) and coronary angiogram (OR = 2.6, 95% CI 1.5-4.6) (both p < 0.001) were associated with PVE. Six-month mortality after PVE was 24% and was higher for healthcare-associated PVE than for non-healthcare-associated PVE (HR = 1.3, 95% CI 1.1-1.5, p = 0.002).

CONCLUSIONS

The risk of PVE is significantly higher for 90 days after healthcare exposures and associated with high mortality.

Clinical and echocardiographic characteristics associated with the development of infective endocarditis in patients with significant mitral stenosis

BACKGROUND

Infective endocarditis (IE) confers significant mortality and morbidity in patients with underlying mitral stenosis (MS), with both diseased native valves and after valvular procedures.

PURPOSE

We examined the clinical and echocardiographic parameters in association with the development of IE on patients with significant MS.

METHODS

A total of 478 consecutive patients with index echocardiographic diagnosis of significant mitral stenosis (mitral valve area <1.5 cm² ) were included. Patients were grouped into those with or without IE on at least 5 years of follow-up. Baseline clinical, echocardiographic profile and clinical outcomes were compared.

RESULTS

IE was observed in 4.4% (n = 21) of the cohort. These patients were younger (45.3 ± 14.6 vs. 53.2 ± 15.5 years, p = 0.022) at the time of MS diagnosis. NT-proBNP was higher in patients who developed IE (13529 ± 12230 vs. 4381 ± 5875 pg/ml, p < 0.001), with larger left atrial diameter (54.4 ± 10.1 vs. 49.9 ± 9.5 mm, p = 0.040) and elevated pulmonary artery systolic pressure (PASP, 62.3 ± 17.2 vs. 47.2 ± 16.5 mmHg, p = 0.026). There was no significant difference in terms of MS severity, other concomitant valvulopathies, or etiology (rheumatic or degenerative) of MS. Patients who smoked had higher incidence of IE (33.3% vs. 14.2%, log-rank 7.27, p = 0.007). After adjusting for age, valve procedure and PASP, patients who smoked remained at elevated risk of IE (adjusted hazards ratio 2.99, 95% confidence interval 1.18-7.56, p = 0.021).

CONCLUSION

IE occurs in a proportion of patients with MS. Smoking, younger age of diagnosis of MS as well as dilated left atria with elevated PASP may be associated with an elevated risk of this complication.

A fatal case of early prosthetic valve endocarditis caused by multidrug-resistant (MDR) - Sphingomonas paucimobilis

Sphyngomonas paucimobilis (S. paucimobilis) is a low-pathogenicity, gram-negative bacilli (GNB) that are previously known as an opportunist microorganism. Recent studies have shown that S. paucimobilis is an emerging pathogen causing various infections. Multidrug-resistant GNB has emerged as a major clinical and therapeutic dilemma in various hospital-associated infections. Although rare, S. paucimobilis could be associated with infective endocarditis (IE). Prosthetic valve endocarditis (PVE) is the most severe type of IE, which has high mortality rates despite diagnostic and treatment advances. We report a fatal case of early PVE associated with multidrug-resistant (MDR) - S. paucimobilis complicated with perivalvular abscess, complete heart block, valve detachment, and septic arthritis.

Valve-related factors and incidence of prosthetic valve endocarditis

Aim

The aim of the study was to present our experience and evaluate the valve-related factors and the incidence of prosthetic valve endocarditis.

Material and methods

This is a retrospective study. Between 2010 and 2018, 36 patients were re-operated on due to prosthetic valve endocarditis The valve-related factors (type, size and position of the prosthetic valve) were analysed.

Results

Thirty-six patients had prosthetic valve endocarditis. The overall hospital mortality was 16.67%. Early vs. late onset prosthetic valve endocarditis mortality was 23.08% vs. 13.04% respectively. The type, size or position of the prosthesis was not associated with prosthetic valve endocarditis. There was a statistically significant difference between occurrence of prosthetic infection between mitral repair and replacement both in mechanical and biological valve groups. The most common infective agent in the early onset group was Staphylococcus aureus, whereas in the late onset group it was Enterococcus faecalis. Out of 13 patients with early prosthetic valve endocarditis, 11 had infection in the perioperative period around primary operation.

Conclusions

Based on our experience, prosthetic valve endocarditis has a high mortality. Early onset prosthetic valve endocarditis is less common but has higher mortality compared to the late onset. Mitral valve repair was less prone to develop prosthetic valve endocarditis, and valve-related factors (type and size of the valve, valve position) did not have any influence on the incidence of prosthetic valve endocarditis.

Infective endocarditis after transcatheter aortic valve implantation: a nationwide study

AIMS

Transcatheter aortic valve implantation (TAVI), now a common procedure to treat high-risk patients with severe aortic stenosis, has rapidly been expanding into younger and lower-risk populations, creating a need to better understand long-term outcome after TAVI. The aim of the present investigation was to determine the incidence, risk factors for, clinical presentation of, and outcome after prosthetic valve endocarditis (PVE) in patients treated with TAVI in a nationwide study.

METHODS AND RESULTS

Three registries were used: a national TAVI registry, a national diagnosis registry, and a national infective endocarditis registry. Combining these registries made it possible to perform a nationwide, all-comers study with independent and validated reporting of PVE in 4336 patients between 2008 and mid-2018. The risk for PVE after TAVI was 1.4% (95% confidence interval 1.0-1.8%) the first year and 0.8% (0.6-1.1%) per year thereafter. One-year survival after PVE diagnosis was 58% (49-68%), and 5-year survival was 29% (17-41%). Body surface area, estimated glomerular filtration rate <30 mL/min/1.73 m2, critical pre-operative state, mean pre-procedural valve gradient, amount of contrast dye used, transapical access, and atrial fibrillation were identified as independent risk factors for PVE. Staphylococcus aureus was more common in early (<1 year) PVE. Infection with S. aureus, root abscess, late PVE, and non-community acquisition was associated with higher 6-month mortality.

CONCLUSION

The incidence of PVE was similar to that of surgical bioprostheses. Compromised renal function was a strong risk factor for developing PVE. In the context of PVE, TAVI seems to be a safe option for patients.

CLINICAL TRIAL REGISTRATION

NCT03768180 (http://clinicaltrials.gov/).

Role of age and comorbidities in mortality of patients with infective endocarditis

PURPOSE

The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality.

METHODS

Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk.

RESULTS

A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32-3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39-1.88),and non-performed surgery (HR:1.64;95% CI:11.16-1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality.

CONCLUSION

There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group.

Comparison of Incidence, Predictors, and Outcomes of Early Infective Endocarditis after Transcatheter Aortic Valve Implantation Versus Surgical Aortic Valve Replacement in the United States

Infective endocarditis (IE) of prosthetic or bioprosthetic heart valves is a serious complication associated with significant morbidity and mortality. Data on the incidence, risk factors, and outcomes of IE after transcatheter aortic valve implantation (TAVI) in the United States are limited. We used the 2013 to 2014 Nationwide Readmissions Databases to determine the incidence of early IE after TAVI and surgical aortic valve replacement (SAVR) in the US. Clinical characteristics, independent predictors, and outcomes of patients with IE post-TAVI were examined. In 29,306 TAVI and 66,077 SAVR patients, the incidence rates of early IE were 1.7% (95% confidence interval [CI] 1.5% to 1.9%) and 2.5% (95% CI 2.3% to 2.9%) per person-year, respectively. In a propensity-matched cohort of 15,138 TAVI and 15,030 SAVR patients (weighted), there were no significant differences in the incidence rates of IE (1.7% [95% CI 1.4% to 2.0%] vs 1.9% [95% CI 1.6% to 2.2%] per person-year, log-rank p = 0.29) or in the median (interquartile range) time to IE (91 [48 to 146] vs 92 [61 to 214] days, p = 0.13). Staphylococcus (30.4%), Streptococcus (29.9%), and Enterococcus (20.5%) were the most common causative organisms of IE post-TAVI. Younger age, history of heart failure, need for permanent pacemaker placement, cardiac arrest, major bleeding, and sepsis during the index TAVI hospitalization were independently associated with an increased risk of IE. In-hospital mortality rate during readmission for IE was 15.6%. In conclusion, in a nationally representative cohort of TAVI patients in the US, the incidence rate of early IE was 1.7% per person-year. Age, co-morbid conditions, invasive procedures, and complications during the index hospitalization were associated with incident IE post-TAVI.

Prosthetic valve endocarditis - A trouble or a challenge?

Prosthetic valve endocarditis (PVE) represents a rare and serious complication of valve replacement associated with high morbidity and mortality, which significantly differs from native valve endocarditis (NVE). There are two major problems: establishing diagnosis and treatment of PVE. Diagnosis in PVE is challenging and often requires several imaging methods besides standard microbiological analyzes. Transesophageal echocardiographic examination remains the widely used imaging technique in PVE diagnosis, but additional techniques such as computed tomography (CT) and ¹⁸F-fluodeoxyglucose positron emission tomography/CT are often necessary. Persistent fever, embolic complications, valve dehiscence, intracardial abscess, heart failure, as well as staphylococcal and fungal PVE require surgical treatment to avoid lethal outcome. The introduction of transcatheter valve implantations and devices significantly complicated the approach - diagnostic and therapeutic to PVE patients. Despite constantly increasing knowledge regarding pathogenesis and treatment of PVE, the optimal therapy remains a matter of debate. Additional studies are necessary to define therapeutic strategies for this potentially fatal complication.

Early Onset Prosthetic Valve Endocarditis: Experience at a Cardiothoracic Surgical Hospital, 2006-2016

BACKGROUND

Early onset prosthetic valve endocarditis (EO-PVE) is an serious complication associated with heart valve replacement surgery.

OBJECTIVES

To describe the epidemiologic, clinical, and laboratory profile of patients with EO-PVE in a cardiac surgical hospital.

PATIENTS AND METHODS

A retrospective analysis of an endocarditis database, implemented prospectively, with a post hoc study driven by analysis of cases of adults with definite endocarditis occurring up to 12 months after heart valve surgery.

RESULTS

We identified 26 cases in 2,496 surgeries in the period 2006-2016. The average annual incidence was 1.04%. The median time between valve replacement and the diagnosis of EO-PVE was 33 days (interquartile range [IQR] 19.25-118.75). Biologic and mechanical prostheses were affected in 53.8% and 46.2%, respectively. Rheumatic disease was present in 57.7% of patients. The most common causative pathogens were Staphylococcus epidermidis (23.1%). No Staphylococcus aureus infection was reported. Complications were present in 73.1% of cases, including embolism (65.4%), acute renal failure (38.5%), and heart failure (23.1%). The mortality rate at 30 days and 12 months was 3.8% and 34.6%, respectively.

CONCLUSIONS

In our cohort EO-PVE was an serious complication of heart valve replacement with a high morbidity and mortality, despite its low frequency.

Surgical treatment of late aortic prosthetic valve endocarditis: 19 years' experience

AIM OF THE STUDY

We retrospectively analyzed the results of operations conducted for aortic prosthetic valve endocarditis in a single center over 19 years.

MATERIAL AND METHODS

From February 1992 to January 2011, we performed operations on 27 patients with aortic prosthetic valve endocarditis. Seventeen patients (63.0%) were male, and the mean age was 39.1 ± 14.2 (16-67) years. Blood cultures were positive in 11 patients (40.7%), and the most commonly identified microorganism was Streptococcus (7 patients, 25.9%). The mean duration of follow-up was 8.6 ± 4.7 years (0.5-18.2), adding up to a total of 136.9 patient/years.

RESULTS

Forty procedures were performed on these 27 patients. The most commonly performed procedure was aortic valve replacement with a prosthetic valve - 16 patients (59.3%). Fifteen patients were operated on during the active phase of infection. In-hospital mortality was observed in 11 patients (40.7%). Postoperatively, 12 patients (44.4%) had low cardiac output, 3 (11.1%) suffered from a heart block; none of them required permanent pacemaker implantation. The actuarial survival for 1 and 5 years was 55.6 ± 9.6% and 47.6 ± 9.7%, respectively.

CONCLUSIONS

Prosthetic valve endocarditis of the aortic valve is a challenging situation for the surgeon. The surgical treatment carries a high mortality rate and long-term survival is low. Among the survivors, however, recurrence and the need for reoperation are unlikely.

The risk for bacterial endocarditis in cirrhotic patients: a population-based 3-year follow-up study

BACKGROUND

We noted only rare reports of cirrhotic patients with bacterial endocarditis (BE). There is insufficient data on the risk of BE in liver cirrhosis. This is the first national population-based study evaluating the risk of BE in cirrhotic patients.

METHODS

We used the National Health Insurance Database, which is derived from the Taiwan National Health Insurance Program. The study cohort comprised 40803 patients with cirrhosis and the comparison cohort consisted of 40841 randomly selected subjects with a similar age and sex distribution.

RESULTS

Of the total 81644 patients, 192 (0.24%) experienced BE during the 3-year follow-up period, 121 patients from the study cohort (0.30% of the cirrhotic patients) and 71 patients from the comparison group (0.17% of non-cirrhotic patients) (p<0.001). After adjusting for patient age, sex, and comorbid disorders, the Cox regression analysis showed that cirrhotic patients had a high risk of BE compared to non-cirrhotic patients during the 3-year follow-up period (hazard ratio 2.04, 95% confidence interval 1.61-2.44, p<0.001).

CONCLUSION

We conclude that liver cirrhosis is a risk factor for the occurrence of BE.

Cardiovascular implantable device infections

As life expectancy continues to increase and biotechnology advances, the use of cardiovascular implantable devices will continue to rise. Unfortunately, despite modern medical advances, the infection and mortality rates remain excessively elevated. This article reviews the pathophysiology and general concepts of cardiac device-related infections, including the physical and chemical characteristics of the medical device, host response to the medical device, and the microbiologic virulence factors. Infections of the most commonly utilized cardiovascular implantable devices, including cardiovascular implantable electronic devices, bioprosthetic and mechanical valves, ventricular assist devices, total artificial hearts, and coronary artery stents, are reviewed in detail.

Prosthetic valve endocarditis: clinicopathological correlates in 122 surgical specimens from 116 patients (1985-2004)

BACKGROUND

Few studies have documented the clinicopathological features of prosthetic valve endocarditis independently of native valve endocarditis.

STUDY DESIGN

Retrospective analysis of patients undergoing cardiac surgery for prosthetic valve endocarditis at our institution (1985-2004).

METHODS

Medical records and microscopic slides were reviewed from 116 patients for demographics, infecting organisms, comorbidities, and pathologic features.

RESULTS

Patients were 12-86 years old (mean, 59 years). Among 122 valves, 64% were from men and 67% were purely regurgitant. Aortic prosthetic valve endocarditis frequently affected men (76%); mitral prosthetic valve endocarditis often affected women (62%). Embolization occurred in 35% and heart failure in 32%. Prevalent predisposing conditions were the prosthetic valve alone (43%) and diabetes mellitus (20%). Prosthetic valve endocarditis was aortic or mitral in 98% and was active in 70%. Annular abscess or paravalvular leak affected mechanical valves more frequently than bioprosthetic (89% vs. 65%; P=.001). Causative organisms (n=116) included Staphylococcus aureus (30%), coagulase-negative staphylococcus (22%), viridans streptococci (18%), enterococci (10%), other streptococci (8%), and other organisms (12%). S. aureus was the most prevalent cause of early-onset (38%) and late-onset (30%) prosthetic valve endocarditis. Coagulase-negative staphylococcus caused early-onset (31%) and most intermediate-onset (40%) disease and had a shorter median implantation-to-infection time than other organisms (6.5 vs. 61.3 months; P<.001). Viridans streptococci and enterococci primarily caused late-onset endocarditis. For active infections by cocci, most cases exhibited strong Gram staining, but four showed only strong Grocott methenamine silver staining.

CONCLUSIONS

Cocci accounted for 83% of infections. Early-onset prosthetic valve endocarditis was primarily staphylococcal, and late-onset prosthetic valve endocarditis resembled native valve endocarditis. Both Gram and Grocott methenamine silver stains were necessary to reliably identify organisms microscopically.

Prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) is associated with a high mortality during the early and midterm follow-up despite diagnostic and therapeutic improvements; its incidence is increasing and reaches 20-30% of all infective endocarditis episodes. In this review, changes in epidemiology, microbiology, diagnosis and therapy that have evolved in the past few years are analyzed. Staphylococci (both Staphylococcus aureus and coagulase-negative Staphylococcus) have emerged as the most common cause of PVE and are associated with a severe prognosis. Moreover, diagnosis may often be difficult because of its complications and extracardiac manifestations; thus, a comprehensive assessment of the clinical, echocardiographic and laboratory data must be performed. Early PVE, comorbidity, severe heart failure and new prosthetic dehiscence are predictors of mortality. Therapy is not indicated by evidence-based recommendations but mostly on identification of the high-risk conditions. A PVE is a common indication for surgery, whereas medical treatment alone may be achieved in a few instances. Systematic prophylaxis should be used to prevent this severe complication of cardiac valve replacement.

The changing face of prosthetic valve endocarditis at a tertiary-care hospital: 1986-2005

INTRODUCTION AND OBJECTIVES

To investigate changes in the clinical characteristics, etiology and prognosis of prosthetic valve endocarditis at a tertiary-care hospital.

METHODS

Retrospective cohort study of all patients diagnosed with prosthetic valve endocarditis using modified Duke criteria between 1986 and 2005. The analysis covered two time periods: January 1986 to December 1995 (P1) and January 1996 to December 2005 (P2).

RESULTS

In total, 133 episodes of endocarditis occurred in 122 patients. Of these, 73 (54.9%) were diagnosed in P1 and 60 (45.1%) in P2, with incidences of 2.19% and 2.18%, respectively. The patients' mean age (SD) was 52.6+/-16.6 years in P1 and 66.2+/-11.5 years in P2 (P=.0001). Clinical characteristics were similar in the two study periods. The increase in Enterococcus infection was remarkable (12.5% in P2 vs. 4.9% in P1; relative risk [RR]=2.5; 95% confidence interval [CI], 0.7-9.6), as was the decrease in viridans group Streptococcus infection (12.5% in P2 vs. 31.1% in P1; RR=0.4; 95% CI, 0.2-0.9). Some 90.4% of patients (63/73) underwent surgery in P1, while 68.3% (41/60) underwent surgery in P2. The difference was significant (RR=0.8; 95% CI, 0.6-0.9). The in-hospital mortality rate was 28.8% in P1 and 30% in P2 (RR=1; 95% CI, 0.6-1.7).

CONCLUSIONS

Changes in the epidemiology and microbiological etiology of prosthetic valve endocarditis were observed over the 20-year study period. Diagnostic and therapeutic approaches also changed, but mortality remained high.

Matching criteria in case-control studies on postoperative infections

Matching is commonly used in case-control studies to control for the effect of major confounding factors. We evaluated the available evidence from case-control studies regarding postoperative infections to identify how frequently matching was performed and with what specific variables. We searched for relevant case-control studies in PubMed until August 2006 and further evaluated those that used individual matching between cases and controls. We identified and evaluated 42 relevant studies. Age was used as a matching criterion in 27 of these 42 (64.3%) case-control studies. The specific type of surgical procedure was the second most commonly used criterion in 17 of 42 studies (40.5%). Gender was used in 14/42 studies (33.3%) as a matching criterion between case and control patients. The period at risk for development of surgical site and/or other postoperative infections, i.e. time from surgery to the diagnosis of infection, was used in nine of 42 studies (21.4%), as was date of operation, and the primary diagnosis that led the case and control patients to surgery. The same surgeon or surgical team was used in seven studies (16.7%); matching according to the National Nosocomial Infection Surveillance system risk score was performed in five studies (11.9%). The findings of our analysis suggest that various characteristics are used for matching in case-control studies of postoperative infections. A more consistent use of matching with the specific type of surgical procedure may help in increasing the internal validity of a case-control study in this field of clinical research.

A forgotten but important risk factor for infective endocarditis in patients with prosthetic valve: pedicure

We report a case of infective endocarditis developing after pedicure in a 36-y-old female. Methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis was diagnosed. Even aggressive therapy was ineffective. To our knowledge, we report the first case of infective endocarditis secondary to pedicure in the literature.