Infective endocarditis: Absence of microbiological diagnosis is an independent predictor of inhospital mortality

Surgery for blood culture-negative infective endocarditis: outcomes and the role of molecular biological imaging as diagnostic approach†

OBJECTIVES

The study aimed to analyse outcomes of surgery for blood culture-negative infective endocarditis (BCNIE) and to evaluate the role of molecular biological imaging.

METHODS

Patients undergoing surgery for native or prosthetic valve endocarditis from 2013 to 2022 were analysed regarding blood culture-positive infective endocarditis (BCPIE) and BCNIE. For laboratory diagnostics in BCNIE, excised valves or prostheses underwent conventional microbiological culture and fluorescence in situ hybridization combined with 16S rRNA-gene polymerase chain reaction and sequencing (FISHseq).

RESULTS

Of 521 patients overall, we identified 473 patients (342 males, mean age 63 ± 14.4 years) with preoperative blood cultures: 396 with BCPIE (83.7%) and 77 with BCNIE (16.3%). Preoperative characteristics and operative procedures were comparable between groups and the calculated perioperative risk (EuroSCORE II) was identical (BCNIE: 12.2 ± 8.8%, BCPIE: 12.9 ± 11.9%, P = 0.788). At surgery, signs of infective endocarditis were present in 71%, missing in 18% and inconclusive in 10% of patients with BCNIE. While valve cultures alone identified pathogens in 32% of BCNIE patients, the combination with FISHseq confirmed the infective aetiology in 98% and identified causative pathogens in 52%. Overall, early mortality was similar in BCNIE (16.9%) and BCPIE (18.2%, P = 0.620), but increased in 37 BCNIE patients without pathogen identification compared to 40 patients with pathogen identification (27.0% vs 7.5%, P = 0.032).

CONCLUSIONS

Integrating FISHseq as molecular biological imaging technique into valve analysis algorithms in patients undergoing surgery for BCNIE increases diagnostic gain and potentially improves outcome.

Epidemiology, Diagnosis, Treatment, and Prognosis of Infective Endocarditis

Infective endocarditis (IE) has experienced enormous changes in recent decades [...].

Coxiella burnetii and Bartonella Endocarditis Diagnosed by Metagenomic Next-Generation Sequencing

(1) Background: Culture-negative endocarditis is challenging to diagnose. Here, we retrospectively identified 23 cases of Coxiella burnetii and Bartonella endocarditis by metagenomic next-generation sequencing. (2) Methods: Twenty-three patients with culture-negative endocarditis were retrospectively enrolled from Guangdong Provincial People's Hospital (n = 23) between April 2019 and December 2021. Metagenomic next-generation sequencing was performed on blood (n = 22) and excised cardiac valvular tissue samples (n = 22) for etiological identification, and Sanger sequencing was performed for pathogenic diagnostic verification. The demographic and clinical data of the 23 patients were obtained from hospital electronic health records. (3) Results: A total of 23 male patients (median age, 56 years (interquartile range, 16)) with culture-negative endocarditis were diagnosed with Coxiella burnetii (n = 21) or Bartonella (n = 2) species infection by metagenomic next-generation sequencing. All patients underwent cardiac surgery. The resected tissue exhibited both a significantly higher number of unique suspected pathogen read-pairs and more unique pathogen read-pairs than the blood specimens. The results of Sanger sequencing tests on all remaining tissue and blood specimens were positive. Oral doxycycline was added to the antibiotic regimen for at least 1.5 years according to etiology. A total of 21 patients (91%) were discharged, and 20 patients were healthy at the 21-month (interquartile range, 15) follow-up visit. One patient exhibited endocarditis relapse with the same pathogen from inadequate antibiotic administration. The last 2 patients (9%) developed septic shock and multiple organ dysfunction syndrome postoperatively and died shortly after discharge. (4) Conclusions: CNE caused by C. burnetii and Bartonella species is challenging to diagnose and exhibits poor outcome due to delayed treatment. In response, mNGS, characterized by high sensitivity and rapid results, is an effective alternative for the etiological identification of C. burnetii and Bartonella endocarditis.

Sex-related disparities in the incidence and outcomes of infective endocarditis according to type 2 diabetes mellitus status in Spain, 2016-2020

BACKGROUND

We performed a study to assess sex-differences in incidence (2016-2020), clinical characteristics, use of therapeutic procedures, and in-hospital outcomes in patients with infective endocarditis (IE) according to T2DM status.

METHODS

Ours was a retrospective cohort study using data from the Spanish National Hospital Discharge Database. We estimated the incidence of hospitalizations for IE in men and women aged ≥ 40 years with and without T2DM. Propensity score matching (PSM) and multivariable logistic regression were used to compare subgroups according to sex and the presence of T2DM.

RESULTS

From 2016 to 2020, IE was coded in 9,958 patients (66.79% men). T2DM was diagnosed in 2,668 (26.79%). The incidence of IE increased significantly from 15.29 cases per 100,000 persons with T2DM in 2016 to 17.69 in 2020 (p < 0.001). However, this increment was significant only among men with T2DM (19.47 cases per 100,000 in 2016 vs. 22.84 in 2020; p = 0.003). The age-adjusted incidence of IE was significantly higher in people with T2DM (both sexes) than in those without T2DM (IRR, 2.86; 95% CI, 2.74-2.99). The incidence of IE was higher in men with T2DM than in women with T2DM (adjusted IRR, 1.85; 95% CI, 1.54-3.31). After PSM, in-hospital mortality (IHM) was higher among T2DM women than matched T2DM men (22.65% vs. 18.0%; p = 0.018). The presence of T2DM was not associated with IHM in men or women.

CONCLUSIONS

T2DM is associated with a higher incidence of hospitalization for IE. Findings for T2DM patients who had experienced IE differed by sex, with higher incidence rates and lower IHM in men than in women. T2DM was not associated to IHM in IE in men or in women.

Outcomes of culture-negative vs. culture-positive infective endocarditis: the ESC-EORP EURO-ENDO registry

AIM

Fatality of infective endocarditis (IE) is high worldwide, and its diagnosis remains a challenge. The objective of the present study was to compare the clinical characteristics and outcomes of patients with culture-positive (CPIE) vs. culture-negative IE (CNIE).

METHODS AND RESULTS

This was an ancillary analysis of the ESC-EORP EURO-ENDO registry. Overall, 3113 patients who were diagnosed with IE during the study period were included in the present study. Of these, 2590 (83.2%) had CPIE, whereas 523 (16.8%) had CNIE. As many as 1488 (48.1%) patients underwent cardiac surgery during the index hospitalization, 1259 (48.8%) with CPIE and 229 (44.5%) with CNIE. The CNIE was a predictor of 1-year mortality [hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.04-1.56], whereas surgery was significantly associated with survival (HR 0.49, 95% CI 0.41-0.58). The 1-year mortality was significantly higher in CNIE than CPIE patients in the medical subgroup, but it was not significantly different in CNIE vs. CPIE patients who underwent surgery.

CONCLUSION

The present analysis of the EURO-ENDO registry confirms a higher long-term mortality in patients with CNIE compared with patients with CPIE. This difference was present in patients receiving medical therapy alone and not in those who underwent surgery, with surgery being associated with reduced mortality. Additional efforts are required both to improve the aetiological diagnosis of IE and identify CNIE cases early before progressive disease potentially contraindicates surgery.

Infective Endocarditis in the Elderly: Challenges and Strategies

The specific management of infective endocarditis (IE) in elderly patients is not specifically addressed in recent guidelines despite its increasing incidence and high mortality in this population. The term "elderly" corresponds to different ages in the literature, but it is defined by considerable comorbidity and heterogeneity. Cancer incidence, specifically colorectal cancer, is increased in older patients with IE and impacts its outcome. Diagnosis of IE in elderly patients is challenging due to the atypical presentation of the disease and the lower performance of imaging studies. Enterococcal etiology is more frequent than in younger patients. Antibiotic treatment should prioritize diminishing adverse effects and drug interactions while maintaining the best efficacy, as surgical treatment is less commonly performed in this population due to the high surgical risk. The global assessment of elderly patients with IE, with particular attention to frailty and geriatric profiles, should be performed by multidisciplinary teams to improve disease management in this population.

Bartonella Endocarditis in Spain: Case Reports of 21 Cases

Blood culture negative endocarditis (BCNE) is frequent in infective endocarditis (IE). One of the causes of BCNE is fastidious microorganisms, such as Bartonella spp. The aim of this study was to describe the epidemiologic, clinical characteristics, management and outcomes of patients with Bartonella IE from the “Spanish Collaboration on Endocarditis-Grupo de Apoyo al Manejo de la Endocarditis infecciosa en España (GAMES)”cohort. Here we presented 21 cases of Bartonella IE. This represents 0.3% of a total of 5590 cases and 2% of the BCNE from the GAMES cohort. 62% were due to Bartonella henselae and 38% to Bartonella quintana. Cardiac failure was the main presenting form (61.5% in B. hensalae, 87.5% in B. quintana IE) and the aortic valve was affected in 85% of the cases (76% in B. henselae, 100% in B. quintana IE). Typical signs such as fever were recorded in less than 40% of patients. Echocardiography showed vegetations in 92% and 100% of the patients with B. henselae and B. quintana, respectively. Culture was positive only in one patient and the remaining were diagnosed by serology and PCR. PCR was the most useful tool allowing for diagnosis in 16 patients (100% of the studied valves). Serology, at titers recommended by guidelines, only coincided with PCR in 52.4%. Antimicrobial therapy, in different combinations, was used in all cases. Surgery was performed in 76% of the patients. No in-hospital mortality was observed. One-year mortality was 9.4%. This article remarks the importance for investigating the presence of Bartonella infection as causative agent in all BCNE since the diagnosis needs specific microbiological tools and patients could benefit of a specific treatment.

Molecular diagnosis of Coxiella burnetii in culture negative endocarditis and vascular infection in South Korea

BACKGROUND

Q fever endocarditis is a major cause of culture-negative endocarditis. The role of Coxellia burnetii is underestimated because it is difficult to diagnose. We investigated the significance of C. burnetii as the cause of culture-negative endocarditis and vascular infection by examining blood and tissue specimens using serological testing and polymerase chain reaction (PCR).

METHODS

All patients with infective endocarditis or large vessel vasculitis were prospectively enrolled at a tertiary-care hospital from May 2016 through September 2020. Q fever endocarditis and vascular infection were diagnosed based on: (1) positive PCR for a cardiac valve or vascular tissue, (2) positive PCR for blood or phase I immunoglobulin G (IgG) ≥ 6400, or (3) phase I IgG ≥ 800 and < 6400 with morphologic abnormality. PCR targeted C. burnetii transposase gene insertion element IS1111a.

RESULTS

Of the 163 patients, 40 (25%) had culture-negative endocarditis (n = 35) or vascular infection (n = 5). Of the 40 patients, 24 (60%) were enrolled. Eight (33%) were diagnosed with Q fever endocarditis or vascular infection. Of these 8 patients, 6 had suspected acute Q fever endocarditis or vascular infection with negative phase I IgG. Six patients were not treated for C. burnetii, 4 were stable after surgery. One patient died due to surgical site infection after 5 months post-operatively and one died due to worsening underlying disease.

CONCLUSIONS

Approximately one-third of patients with culture-negative endocarditis and vascular infection was diagnosed as Q fever. Q fever endocarditis and vascular infection may be underestimated in routine clinical practice in South Korea.KEY MESSAGEQ fever endocarditis and vascular infection may be underestimated in routine clinical practice, thus, try to find evidence of C. burnetti infection in suspected patients by all available diagnostic tests including PCR.

Blood culture-negative infective endocarditis: a worse outcome? Results from a large multicentre retrospective Spanish cohort study

BACKGROUND

To assess the impact of blood cultures negative infective endocarditis (BCNIE) on in-hospital mortality.

METHODS

Prospective multicentre study with retrospective analysis of a Spanish cohort including adult patients with definite IE. Cardiac implantable devices infection were excluded. Comparisons between blood cultures positive and BCNIE groups were performed to analyse in-hospital mortality.

RESULTS

1001 cases were included of which 83 (8.3%) had BCNIE. Alternative microbiological diagnosis was achieved for 39 (47%) out 83 cases. The most frequent identifications were: Coxiella burnetii (11; 28.2%), Tropheryma whipplei (4; 10.3%), Streptococcus gallolyticus (4;10.3%) and Staphylococcus epidermidis (3; 7.7%). Surgery was performed more frequently in BCNIE group (57.8 vs. 36.9%, p < .001). All-cause in-hospital mortality rate was 26.7% without statistical difference between compared groups. BCNIE was not associated to worse mortality rate in Cox regression model (aHR = 1.37, 95% CI 0.90-2.07, p = .14). Absence of microbiological diagnosis was also not associated to worse in-hospital prognosis (aHR = 1.62, 95% CI 0.99-2.64, p = .06).

CONCLUSIONS

In our cohort, BCNIE was not associated to greater in-hospital mortality based in multivariate Cox regression models. The variables most frequently associated with mortality were indicated but not performed surgery (aHR = 2.48, 95% CI 1.73-3.56, p < .001), septic shock (aHR = 2.24, 95% CI 1.68-2.99, p < .001), age over 65 years (aHR = 1.88, 95% CI 1.40-2.52, p < .001) and complicated endocarditis (aHR = 1.79, 95% CI 1.36-2.37, p < .001).

Culture-negative infective endocarditis (CNIE): impact on postoperative mortality

Introduction

Poor postoperative outcomes have been reported after surgery for infective endocarditis (IE). Whether the absence of positive cultures impacts the prognosis remains a matter of discussion. The aim of this study was to evaluate the impact of negative cultures on the prognosis of surgically treated IE.

Methods

This was a single-center, retrospective study. From January 2000 to June 2019, all patients who underwent valvular surgery for IE were included in the study. The primary endpoint was early postoperative mortality. A covariate balancing propensity score was developed to minimize the differences between the culture-positive IE (CPIE) and culture-negative IE (CNIE) cohorts. Using the estimated propensity scores as weights, an inverse probability treatment weighting (IPTW) model was built to generate a weighted cohort. Then, to adjust for confounding related to CPIE and CNIE, a doubly robust method that combines regression model with IPTW by propensity score was adopted to estimate the causal effect of the exposure on the outcome.

Results

During the study period, 327 consecutive patients underwent valvular repair/replacement with the use of cardiopulmonary bypass and cardioplegic cardiac arrest for IE. Their mean age was 61.4 ± 15.4 years, and 246 were males (75.2%). Native valve IE and prosthetic valve IE accounted for 87.5% and 12.5% of cases, respectively. Aortic (182/327, 55.7%) and mitral valves (166/327, 50.8%) were mostly involved; 20.5% of isolated mitral valve diseases were repaired (22/107 patients). The tricuspid valve was involved in 10 patients (3.3%), and the pulmonary valve in 1 patient (<1%). Fifty-nine patients had multiple-valve disease (18.0%). Blood cultures were negative in 136/327 (41.6 %). A higher postoperative mortality was registered in CNIE than in CPIE patients (19% vs 9%, respectively, p = 0.01). The doubly robust analysis after IPTW by propensity score showed CNIE to be associated with early postoperative mortality (odds ratio 2.10; 95% CI, 1.04–4.26, p = 0.04).

Conclusions

In our cohort, CNIE was associated with a higher early postoperative mortality in surgically treated IE patients after dedicated adjustment for confounding. In this perspective, any effort to improve preoperative microbiological diagnosis, thus allowing targeted therapeutic initiatives, might lead to overall better postoperative outcomes in surgically treated IE.

Risk Factors for In-Hospital Mortality in Infective Endocarditis

BACKGROUND

Infective endocarditis (IE) is associated with severe complications and high mortality. The assessment of mortality rates and predictors for fatal events is important to identify modifiable factors related to the pattern of treatment, in order to improve outcomes.

OBJECTIVES

We sought to evaluate clinical outcomes of patients with IE and to determine predictors of in-hospital mortality.

METHODS

Retrospective single-center study including patients with IE admitted during a 10-year period (2006-2015). Data on comorbidities, clinical presentation, microbiology and clinical outcomes during hospitalization were evaluated. Risk factors of in-hospital death were analyzed. A p-value < 0.05 was considered significant.

RESULTS

A total of 134 cases were included (73% males, mean age of 61 ± 16 years-old). Half of them had previous valvular heart disease. Healthcare-associated IE and negative blood-cultures occurred in 22% and prosthetic IE in 25%. The aortic valve was the one most often affected by infection. Staphylococcus aureus was the most commonly isolated microorganism. Forty-four (32.8%) patients underwent cardiac surgery. The in-hospital mortality rate was 31.3% (42 patients). The identified risk factors for in-hospital mortality were Staphylococcus aureus etiology (OR 6.47; 95% CI: 1.07-39.01; p = 0.042), negative blood-cultures (OR 9.14; 95% CI: 1.42-58.77; p = 0.02), evidence of valve obstruction in echocardiography (OR 8.57; 95% CI: 1.11-66.25; p = 0.039), clinical evolution with heart failure (OR 4.98; 95%CI: 1.31-18.92; p = 0.018) or septic shock (OR 20.26; 95% CI: 4.04-101.74; p < 0.001). Cardiac surgery was a protective factor of mortality (OR 0.14; 95% CI 0.03-0.65; p = 0.012).

CONCLUSION

The risk factors for in-hospital mortality were clinical (heart failure, septic shock), evidence of valve obstruction in echocardiography, Staphylococcus aureus etiology or negative blood cultures. Invasive treatment by surgery significantly decreased the mortality risk.

Short- and long-term mortality in patients with left-sided infective endocarditis not undergoing surgery despite indication

INTRODUCTION AND OBJECTIVES

In infective endocarditis (IE), decisions on surgical interventions are challenging and a high percentage of patients with surgical indication do not undergo these procedures. This study aimed to evaluate the short- and long-term prognosis of patients with surgical indication, comparing those who underwent surgery with those who did not.

METHODS

We included 271 patients with left-sided IE treated at our institution from 2003 to 2018 and with an indication for surgery. There were 83 (31%) surgery-indicated not undergoing surgery patients with left-sided infective endocarditis (SINUS-LSIE). The primary outcome was all-cause death by day 60 and the secondary outcome was all-cause death from day 61 to 3 years of follow-up. Multivariable Cox regression and propensity score matching were used for the analysis.

RESULTS

At the 60-day follow-up, 40 (21.3%) surgically-treated patients and 53 (63.9%) SINUS-LSIE patients died (P <.001). Risk of 60-day mortality was higher in SINUS-LSIE patients (HR, 3.59; 95%CI, 2.16-5.96; P <.001). Other independent predictors of the primary endpoint were unknown etiology, heart failure, atrioventricular block, and shock. From day 61 to the 3-year follow-up, there were no significant differences in the risk of death between surgically-treated and SINUS-LSIE patients (HR, 1.89; 95%CI, 0.68-5.19; P=.220). Results were consistent after propensity score matching. Independent variables associated with the secondary endpoint were previous IE, diabetes mellitus, and Charlson index.

CONCLUSIONS

Two-thirds of SINUS-LSIE patients died within 60 days. Among survivors, the long-term mortality depends more on host conditions than on the treatment received during admission.

The role of 99mTc-HMPAO-labelled white blood cell scintigraphy in the diagnosis of cardiac device-related infective endocarditis

Aims

The hybrid technique of single-photon emission tomography and computed tomography with technetium99m-hexamethylpropyleneamine oxime–labelled leucocytes (99mTc-HMPAO-SPECT/CT) is an emerging diagnostic technique in patients with cardiac device-related infective endocarditis (CDRIE). This prospective study assessed the 99mTc-HMPAO-SPECT/CT diagnostic profile and its added value to the modified Duke criteria (mDuke) in CDRIE diagnostic work-up.

Methods and results

The study examined 103 consecutive patients with suspected CDRIE, who underwent 99mTc-HMPAO-SPECT/CT. Diagnostic accuracy was calculated based on a final clinical CDRIE diagnosis, including microbiology, echocardiography, and a 6-month follow-up. Subsequently, we compared the diagnostic value of the initial mDuke classification with a classification including 99mTc-HMPAO-SPECT/CT positive results as an additional major CDRIE criterion: mDuke-SPECT/CT.

Overall, CDRIE was diagnosed in 31 (31%) patients, whereas 35 (34%) 99mTc-HMPAO-SPECT/CT were positive. 99mTc-HMPAO-SPECT/CT was characterized by 86% accuracy, 0.69 Cohen’s kappa coefficient, 84% sensitivity, 88% specificity, 93% negative, and 74% positive predictive values. The original mDuke displayed 83% accuracy, 0.52 kappa, whereas mDuke-SPECT/CT had 88% accuracy, and 0.73 kappa. Compared with mDuke, mDuke-SPECT/CT showed significantly higher sensitivity (87% vs. 48%, P &lt; 0.001). According to mDuke, 49.5% of patients had possible CDRIE, and after reclassification, that figure dropped to 37%. Furthermore, having assessed the diagnosis categorization improvement following the incorporation of 99mTc-HMPAO-SPECT/CT, the net reclassification index value was found to be 31.4%.

Conclusion

In patients with CDRIE, 99mTc-HMPAO-SPECT/CT provides high diagnostic accuracy, whereas a negative scan excludes CDRIE with high probability. Inclusion of 99mTc-HMPAO-SPECT/CT into mDuke diagnostic criteria yields significantly higher sensitivity and a reduction in possible CDRIE diagnoses.

Antimicrobial management of Tropheryma whipplei endocarditis: the Spanish Collaboration on Endocarditis (GAMES) experience

OBJECTIVES

Tropheryma whipplei has been detected in 3.5% of the blood culture-negative cases of endocarditis in Spain. Experience in the management of T. whipplei endocarditis is limited. Here we report the long-term outcome of the treatment of previously reported patients who were diagnosed with infective endocarditis (IE) caused by T. whipplei from the Spanish Collaboration on Endocarditis-Grupo de Apoyo al Manejo de la Endocarditis Infecciosa en España (GAMES) and discuss potential options for antimicrobial therapy for IE caused by T. whipplei.

PATIENTS AND METHODS

Seventeen patients with T. whipplei endocarditis were recruited between 2008 and 2014 in 25 Spanish hospitals. Patients were classified according to the therapeutic regimen: ceftriaxone and trimethoprim/sulfamethoxazole, doxycycline + hydroxychloroquine and other treatment options.

RESULTS

Follow-up data were obtained from 14 patients. The median follow-up was 46.5 months. All patients completed the antibiotic treatment prescribed, with a median duration of 13 months. Six patients were treated with ceftriaxone and trimethoprim/sulfamethoxazole (median duration 13 months), four with doxycycline + hydroxychloroquine (median duration 13.8 months) and four with other treatment options (median duration 22.3 months). The follow-up after the end of the treatments was between 5 and 84 months (median 24 months).

CONCLUSIONS

All treatment lines were effective and well tolerated. Therapeutic failures were not detected during the treatment. None of the patients died or experienced a relapse during the follow-up. Only six patients received antibiotic treatment in accordance with guidelines. These data suggest that shorter antimicrobial treatments could be effective.

99mTc-HMPAO-labeled leukocyte SPECT/CT and transthoracic echocardiography diagnostic value in infective endocarditis

Infective endocarditis (IE) is a life-threatening disease, establishing a diagnosis is often challenging. The aim of this prospective study was to evaluate and compare the diagnostic performance of the combined use of single photon emission tomography and computed tomography with technetium99m-hexamethylpropyleneamineoxime—labeled leukocytes (99mTc-HMPAO-SPECT/CT) with transthoracic echocardiography (TTE) in patients with suspected IE. We enrolled 40 consecutive patients (12 females, 28 males, mean age: 58.6 ± 18) with suspected IE in the years 2015–2016. All patients underwent clinical evaluation, TTE and 99mTc-HMPAO-SPECT/CT for the assessment of lesions typical for IE. Scans were evaluated for the presence and location of increased radioactivity foci, corresponding to the accumulation of radiolabeled leukocytes in inflammatory lesions. After 6 months, the patients were re-evaluated clinically and with TTE. Final IE diagnosis was established in 14 (35%) patients. Lesions typical for IE were shown in 28 (70%) TTEs and 16 (40%) 99mTc-HMPAO-SPECT/CTs. The latter tests were characterized by 90% accuracy, 93% sensitivity, 88% specificity, 96% negative predictive value (NPV), 81% positive predictive value (PPV). TTE demonstrated 60% accuracy, 93% sensitivity, 42% specificity, 92% NPV, and 46% PPV. 99mTc-HMPAO-SPECT/CT was characterized by a lower number of false-positive results compared to TTE (3 vs. 15). In patients with suspected IE, 99mTc-HMPAO-SPECT/CT yields a smaller number of false-positive results, significantly higher diagnostic accuracy, specificity and PPV than TTE. It helps to differentiate IE infectious and sterile echocardiographic lesions and reduces by 27% the number of misdiagnosed IE classified in the ‘possible IE’ category by modified Duke Criteria.

Infective endocarditis in Western Norway: a 20-year retrospective survey

BACKGROUND

To investigate epidemiological trends of infective endocarditis (IE) in western Norway a retrospective study was performed.

METHODS

Characteristics of 706 IE admissions from 1996 to 2005 and 2006 to 2015 were analysed and compared using the Chi-square test for categorical variables and the t-test for age. Survival was analysed by multiple Cox regression and reported by the hazard ratio (HR).

RESULTS

Mean annual incidence rates increased from 4.6 to 7.4 per 100,000 inhabitants (rate ratio: 1.97, 95% confidence interval: 1.52-2.56, p < .001). Non-viridans streptococci, enterococci and Staphylococcus aureus (S. aureus), were all independently associated with increased mortality. The frequency of IE caused by enterococci increased from 3.7 to 13.0% (p < .001). The proportion of intravenous drug users (IVDU) increased from 16.5 to 23.5% (p = .015) and had increasing aortic valve involvement (p = .023). Prosthetic valve endocarditis (PVE) constituted 30% of IE cases in both decades with biological PVE increasing from 9.4 to 22.1% (p < .001) and mechanical PVE decreasing from 18.7 to 8.9% (p < .001). In the last decade, valve replacement surgery was performed in 37.6% of the patients, of which 85.5% received a bioprosthesis.

CONCLUSIONS

The incidence of IE increased significantly. Non-viridans streptococci, enterococci and S. aureus were all significantly associated with increased mortality. The increased number of enterococcal IE and the increased number of IVDUs with left-sided IE constituted new challenges. Biological implants were preferred in a majority of patients requiring surgery.

Prognostic implications of a negative echocardiography in patients with infective endocarditis

BACKGROUND

Echocardiography plays an important role in infective endocarditis (IE) diagnosis according with the modified Duke criteria. We evaluated the implications of a positive echocardiography in the prognosis of a cohort of patients with IE.

METHODS

Prospective multicentre study in 31 Spanish centres. From January 2008 to September 2016, 3467 patients were included (2765 definite IE, 702 possible IE). The main outcome was in-hospital mortality. Echocardiography diagnosis was based on modified Duke criteria for the diagnosis of IE.

RESULTS

Median age was 69 years (interquartile range: 57-77 years). Comorbidity was high (mean Charlson index 4.7 ± 2.8). Transoesophageal echocardiography was performed in 2680 (77.3%). The overall inhospital mortality rate was 26.7%. Univariate analysis showed that, in patients with definite IE, inhospital mortality was similar in patients with positive and negative echocardiography (27.7% vs. 24.6%, respectively, p = 0.121). In possible IE these figures were 27.5% vs. 16.7%, respectively, p < 0.001. Complications (cardiac and extracardiac [embolic, immunological, and septic shock]) were more frequent with positive than with negative echocardiography, regardless of clinical suspicion (definite IE 35.5% vs. 16.8%, respectively, p < 0.001; possible IE 20.8% vs. 7.6%, respectively, p < 0.001). Positive echocardiography was a predictor of inhospital death by logistic regression modelling, after adjusting for confounders, definite IE (odds ratio [OR] 1.3, 95% confidence interval [CI] 1.02-1.76, p = 0.036), possible IE (OR 1.59, 95% CI 1.02-2.45, p = 0.036).

CONCLUSIONS

A positive echocardiography in patients with IE is associated with increased inhospital mortality, in addition to other clinical factors and comorbidities.

Laboratory Approach to the Diagnosis of Culture-Negative Infective Endocarditis

Blood-culture negative endocarditis (BCNE) accounts for up to 35% of all cases of infective endocarditis (IE) and is a serious life-threatening condition with considerable morbidity and mortality. Rapid detection and identification of the causative pathogen is essential for timely, directed therapy. Blood-culture negative endocarditis presents a diagnostic and therapeutic challenge. Causes of BCNE are varied including: treatment with antibiotic agents prior to blood culture collection; sub-optimal specimen collection; and/or infection due to fastidious (eg. nutritionally variant streptococci), intracellular (eg. Coxiella burnetii, Bartonella species) or non-culturable or difficult to culture organisms (eg. Mycobacteria, Tropheryma whipplei and fungi); as well as non-infective aetiologies. Here, we review aetiological and diagnostic approaches to BCNE including newer molecular based techniques, with a brief summary of imaging investigation and treatment principles.