Diagnosis Of Prosthetic Valve Endocarditis Research Articles

Abstract 18958: Management of Patients With Suspected Left-Sided Prosthetic Valve Endocarditis According to Myocardial FDG-PET CT Results

Introduction: Accurate diagnosis of prosthetic valve endocarditis (PVE) is challenging because echocardiography (Echo) can be limited by artifact from prosthetic material. Myocardial FDG-PET (PET) can improve diagnostic accuracy; however, little is known about its effect on patient management. Research Question: Does PET affect management of patients with suspected left-sided PVE? Methods: A retrospective, single-center study was conducted on all admitted patients with a history of aortic valve replacement (AVR) or mitral valve replacement (MVR) or repair who underwent a myocardial PET for suspected endocarditis between April 2016 to December 2022. PET was defined as positive, negative, or indeterminate based on signal intensity/pattern at valve prosthesis. For this analysis, patients with indeterminate results were included with negative results, resulting in four groups PET+, PET-, Echo+ and Echo-. Patients were followed up to twelve months. Data were obtained from chart review and supplemented with national death index data. Results: Of a total of 146 included patients, 68% had a surgical AVR, 14% had a transcatheter AVR and 21% had an MVR. Median age was 63 years and 30% of patients were female. Most patients had positive blood cultures on admission (66%). The Echo+/PET+ group had a high rate of definite PVE (95%). PVE was rejected in 58% of those in the Echo-/PET- group. PET+ patients were more likely to undergo surgery in both the Echo- (24% for PET+ vs. 12% for PET-) and Echo+ (62% for PET+ vs. 20% for PET-) groups. High rates of prolonged antibiotic courses (73%) were seen across all groups; PET- groups had lower rates of prolonged antibiotics. Conclusions: Although most patients with suspected PVE underwent initial conservative management, PET+ patients had higher rates of surgical management. Negative PET results may help to identify patients with suspected PVE that may not require prolonged antibiotics.

18F-FDG-Based Radiomics and Machine Learning: Useful Help for Aortic Prosthetic Valve Infective Endocarditis Diagnosis?

BackgroundFluorine-18 fluorodeoxyglucose (18F-FDG)-positron emission tomography (PET)/computed tomography (CT) results in better sensitivity for prosthetic valve endocarditis (PVE) diagnosis, but visual image analysis results in relatively weak specificity and significant interobserver variability. ObjectivesThe primary objective of this study was to evaluate the performance of a radiomics and machine learning–based analysis of 18F-FDG PET/CT (PET-ML) as a major criterion for the European Society of Cardiology score using machine learning as a major imaging criterion (ESC-ML) in PVE diagnosis. The secondary objective was to assess performance of PET-ML as a standalone examination. MethodsAll 18F-FDG-PET/CT scans performed for suspected aortic PVE at a single center from 2015 to 2021 were retrospectively included. The gold standard was expert consensus after at least 3 months’ follow-up. The machine learning (ML) method consisted of manually segmenting each prosthetic valve, extracting 31 radiomics features from the segmented region, and training a ridge logistic regressor to predict PVE. Training and hyperparameter tuning were done with a cross-validation approach, followed by an evaluation on an independent test database. ResultsA total of 108 patients were included, regardless of myocardial uptake, and were divided into training (n = 68) and test (n = 40) cohorts. Considering the latter, PET-ML findings were positive for 13 of 22 definite PVE cases and 3 of 18 rejected PVE cases (59% sensitivity, 83% specificity), thus leading to an ESC-ML sensitivity of 72% and a specificity of 83%. ConclusionsThe use of ML for analyzing 18F-FDG-PET/CT images in PVE diagnosis was feasible and beneficial, particularly when ML was included in the ESC 2015 criteria. Despite some limitations and the need for future developments, this approach seems promising to optimize the role of 18F-FDG PET/CT in PVE diagnosis.

A Case of Recurrent Infective Endocarditis Caused by Streptococcus Agalactiae.

A 53-year-old man was admitted to hospital with a high fever and shivering. He had undergone aortic valve replacement 4 years previously due to infective endocarditis caused by Streptococcus agalactiae. 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) showed increased uptake in the tissue surrounding the prosthetic valve. S. agalactiae was detected in blood cultures after admission. We made a diagnosis of prosthetic valve endocarditis due to an S. agalactiae infection relapse. After 6 weeks of antibacterial treatment, the inflammatory findings successfully improved. However, reexamination with 18F-FDG PET/CT suggested the possibility of persistent prosthetic valve infection. Therefore, we decided to continue the oral antibiotic treatment after discharge.

Infective Endocarditis after Transcatheter Aortic Valve Replacement: Challenges in the Diagnosis and Management

Although initially conceived for high-risk patients who are ineligible for surgical aortic valve replacement (SAVR), transcatheter aortic valve replacement (TAVR) is now recommended in a wider spectrum of indications, including among young patients. However, similar to SAVR, TAVR is also associated with a risk of infectious complications, namely, prosthetic valve endocarditis (PVE). As the number of performed TAVR procedures increases, and despite the low incidence of PVE post-TAVR, clinicians should be familiar with its associated risk factors and clinical presentation. Whereas the diagnosis of native valve endocarditis can be achieved straightforwardly by applying the modified Duke criteria, the diagnosis of PVE is more challenging given its atypical symptoms, the lower sensitivity of the criteria involved, and the low diagnostic yield of conventional echocardiography. Delay in proper management can be associated with increased morbidity and mortality. Therefore, clinicians should have a high index of suspicion and initiate proper work-up according to the severity of the illness, the underlying host, and the local epidemiology of the causative organisms. The most common causative pathogens are Gram-positive bacteria such as Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus spp., and Streptococcus spp. (particularly the viridans group), while less-likely causative pathogens include Gram-negative and fungal pathogens. The high prevalence of antimicrobial resistance complicates the choice of therapy. There remain controversies regarding the optimal management strategies including indications for surgical interventions. Surgical assessment is recommended early in the course of illness and surgical intervention should be considered in selected patients. As in other PVE, the duration of therapy depends on the isolated pathogen, the host, and the clinical response. Since TAVR is a relatively new procedure, the outcome of TAVR-PVE is yet to be fully understood.

Multimodality Imaging in the Diagnosis of Prosthetic Valve Endocarditis: A Brief Review.

Infective endocarditis is a common and treatable condition that carries a high mortality rate. Currently the workup of infective endocarditis relies on the integration of clinical, microbiological and echocardiographic data through the use of the modified Duke criteria (MDC). However, in cases of prosthetic valve endocarditis (PVE) echocardiography can be normal or non-diagnostic in a high proportion of cases leading to decreased sensitivity for the MDC. Evolving multimodality imaging techniques including leukocyte scintigraphy (white blood cell imaging), 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), multidetector computed tomographic angiography (MDCTA), and cardiac magnetic resonance imaging (CMRI) may each augment the standard workup of PVE and increase diagnostic accuracy. While further studies are necessary to clarify the ideal role for each of these imaging techniques, nevertheless, these modalities hold promise in determining the diagnosis, prognosis, and care of PVE. We start by presenting a clinical vignette, then evidence supporting various modality strategies, balanced by limitations, and review of formal guidelines, when available. The article ends with the authors' summary of future directions and case conclusion.

Analysis of factors affecting the accuracy of 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography in case of suspected prosthetic valve infective endocarditis

Aim. To analyze the factors affecting the accuracy of 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (PET/CT) in case of suspected prosthetic valve endocarditis (PVE).Material and methods. The results of PET/CT performed in 66 patients after heart valve replacement were analyzed: 55 patients with suspected PVE (≥3 months after surgery) and 11 comparison groups without PVE (2 months after surgery). In the group with suspected PVE (n=55) at the time of the study, 27% (15/55) had a normal body temperature, 85% (47/55) — no leukocytosis. In 16% (9/55), the examination was performed from 3 to 6 months after surgery and in 67% (37/55) — against the background of long-term antibiotic therapy (ABT). The final diagnosis of PVE was made on the basis of clinical (including 6±3 followup), laboratory, instrumental, and intraoperative (n=40) data: confirmed — in 37 patients; ruled out — in 29 patients. In order to determine the influence of factors on obtaining false PET/CT results, the odds ratio was calculated.Results. In the group with suspected PVE (n=55), the PET/CT results made it possible to establish and rule out PVE in 92% (34/37) and 67% (12/18) of patients, respectively. In 16% (9/55) of patients, false positive (n=6) and false negative (n=3) results. Thus, the sensitivity, specificity and diagnostic accuracy of PET/CT in the diagnosis of PVE were 92%, 67% and 84%, respectively; positive and negative predictive values — 85% and 80%. The analysis of the odds ratio did not reveal the relationship of low inflammatory activity, the interval between surgery and PET/CT from 3 to 6 months, and long-term ABT before PET/CT with false PET/CT results (p>0,05). In the comparison group without PVE (n=11), 91% (10/11) received false positive PET/CT results, and one patient received a true negative result.Conclusion. The data obtained indicate the high informative value of PET/CT in the diagnosis of PVE. Interval >2 months between surgery and PET/CT significantly reduces the accuracy of PET/CT results. Other factors analyzed in the presented group did not affect the accuracy of PET/CT results.

The valve uptake index: a new measure in [18F]FDG PET/CT for the diagnosis of prosthetic valve endocarditis

Abstract Background Diagnosis of PVE by PET/CTA is based on visual and quantitative evaluation of morpho-metabolic features. The FDG uptake pattern is a main diagnostic criterion, but can be visually unclear and susceptible to subjectivity. The valve uptake index (VUI) is a new measure designed to provide a more objective indication of the distribution of metabolic activity. Purpose To validate the diagnostic accuracy of the valve uptake index (VUI) (SUVmax-SUVmean)/SUVmax, in patients with suspicion of prosthetic valve endocarditis (PVE). To establish a cut-off value that allows diagnosis of infection. Finally, to determine the incremental value of adding the VUI to the classic parameters for the diagnostis of PVE by PET/CT. Methods Retrospective analysis of 122 patients, with a conclusive diagnosis of definite or rejected PVE and who had undergone a cardiac PET/CTA scan. We measured the VUI and recorded the SUVmax, SUVratio, uptake pattern and the presence of endocarditis-related anatomic lesions. The diagnostic accuracy of these parameters was calculated. Results The VUI values were 0.54±0.1 vs. 0.36±0.08 in the definite PVE group vs. the rejected group, respectively (mean±SD; p<0.001). A cut-off value of VUI>0.45 showed a sensitivity, specificity and diagnostic accuracy for PVE of 85%, 90.3% and 87.4%, and significantly increased diagnostic ability for confirming endocarditis when combined with the standard diagnostic criteria. Conclusions The VUI had good diagnostic accuracy for PVE. The diagnostic power of currently used morphometabolic parametersis significantly increased by the addition of the VUI. Integration of the VUI in the diagnostic algorithm may clarify doubtful cases, and improve the diagnostic yield of PET/CTA. Funding Acknowledgement Type of funding sources: None.

Brucella Prosthetic Valve Endocarditis: A Systematic Review.

ObjectiveBrucella prosthetic valve endocarditis is a rare but a life-threatening complication of brucellosis. It remains a diagnostic challenge. Optimal treatment of Brucella prosthetic valve endocarditis is debated. Available data is limited to case reports or small case series. The purpose of this study was to systematically review all published cases of Brucella prosthetic valve endocarditis in the literature.MethodA systematic review of PubMed database, Google, Google Scholar, and Scopus (From January 1974 to the present) for studies providing epidemiological, clinical and microbiological data as well as data on treatment and outcomes of Brucella prosthetic valve endocarditis was performed.ResultsA total of 51 reported cases were reviewed. Brucella melitensis (45%) and Brucella abortus (11.7%) were the most frequently isolated species. Most common type of prosthesis valve was mechanical prothesis (84.3%) and ten patients had double valve prosthesis (19.6%). Fever and dyspnea were present in 100% and 37.2% of the cases, respectively. The diagnosis was set with echocardiographic finding in 30 cases (93.7%), which revealed vegetation in 27 cases (84.3%). Most used antibiotics were rifampicin, doxycycline and aminoglycoside or cotrimoxazole. No deaths were noted in patients treated by combined medical and surgical treatment, but mortality was noted in 27.7% of the cases treated by antibiotics alone (p = 0.006).ConclusionThis systematic review highlights diagnostic challenges and demonstrates that surgery improved outcome by reducing mortality in patients treated with the combined surgical and medical treatment option. Brucellosis should be considered in the differential diagnosis of prosthetic valve endocarditis in patients residing in or traveling to areas of endemicity.

The role of cardiac computed tomography in the diagnosis of prosthetic valve endocarditis – A comparison with transthoracic and transesophageal echocardiography and intra-operative findings

BackgroundInfective endocarditis is one of the most severe complications after prosthetic valve implantation and an accurate diagnosis is a clinical challenge.The purpose was to assess the diagnostic usefulness of cardiac computed tomography (CT) in valvular and perivalvular complications in patients with prosthetic valve endocarditis (PVE) and to compare CT results with transthoracic echocardiography (TTE), transesophageal echocardiography (TEE) and intraoperative findings. MethodsThe retrospective study included 44 consecutive patients with PVE who underwent cardiac surgery. The mean age was 59.6 ± 12.9 years, 33 (75 %) were males.The presence of vegetations, abscess/pseudoaneurysm, paravalvular leakage (PVL) and inflammatory infiltration were evaluated by TTE, TEE and CT prior to surgery and the results were compared with intraoperative findings. ResultsEndocarditis affected 47 valves (26 mechanical, 21 biological) in 44 patients. PVE most often affected the aortic valve (n = 36), followed by the mitral valve (n = 9) and the pulmonary valve (n = 2). In the per-valve analysis, the sensitivity of TTE, TEE and CT in diagnosing vegetations was 65 %, 91 % and 96 %; abscess 44 %, 77 % and 89 %; paravalvular leakage 90 %, 100 % and 70 %; inflammatory infiltration 39 %, 56 % and 78 %, respectively. The combination of CT and echocardiography allowed the detection of abscesses/pseudoaneurysms and inflammatory infiltration in all cases except one. ConclusionCT was superior to echocardiography in the diagnosis of paravalvular abscesses, vegetations and inflammatory infiltration. Echocardiography had a higher diagnostic value to CT in the evaluation of paravalvular leakage. Cardiac CT combined with echocardiography improves the diagnostic accuracy of PVE and both modalities should be performed.

The usefulness of cardiac computed tomography in the diagnosis of perivalvular complications in patients with prosthetic valve endocarditis

Abstract Background and purpose of the study Echocardiography remains the gold standard for the diagnosis of prosthetic valve endocarditis (PVE). But in around 15% of cases, its results can be false negative due to the acoustic shadow of artificial valves. The aim of the study was compare cardiac computed tomography (CT) with other imaging modalities in the diagnosis of perivalvular complications in patients with PVE. Material and methods The study included 35 consecutive patients with PVE. Thirty of them had an artificial aortic valve (17- mechanical valve, 13-biological valve), 7-mechanical mitral valve, and one patient was after biological pulmonary valve implantation. Three patients were after aortic and mitral valve replacement. Each patient underwent transthoracic (TTE) and transesophageal (TEE) echocardiography. ECG-gated CT examinations were performed with a dual source CT system. All patients were qualified for surgical treatment. The assessment included the presence of vegetation, perivalvular abscess/pseudoaneurysm, inflammatory infiltration and prosthesis dehiscence. Results Intraoperative assessment revealed the presence of vegetations in 16 patients. The sensitivity of echocardiography (TTE+TEE) and CT examinations was 100% and 93% respectively. Twenty one abscesses/pseudoaneurysms were found intraoperatively. The sensitivity of echocardiography and CT examinations was 76% and 85%, respectively. The analysis of total TTE, TEE and CT findings showed that supplementing echocardiography with CT had increased the sensitivity of the method for detecting abscess/pseudoaneurysms to 95%. In a patient in whom no abscesse was found, inflammatory infiltration was diagnosed in echocardiography. Inflammatory infiltration was diagnosed intraoperatively in 13 patients. The sensitivity of echocardiography and CT was 69% in both examinations. The sensitivity of the combination TTE + TEE + CT was 92%. Perivalvular leakage was found intraoperatively in 17 patients. The sensitivity of echocardiography and CT for the diagnosis of this complication was 100% and 87%, respectively. Conclusions CT is better than echocardiography in diagnosing abscesses/pseudoaneurysms and has the same sensitivity in detecting inflammatory infiltration. Adding CT to echocardiography improves the sensitivity of these complications detection. CT is not superior to echocardiography in the diagnosis of vegetations and perivalvular leakage, but it can be a useful tool when echocardiography findings are inconclusive. Funding Acknowledgement Type of funding source: None

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 RegistrationNCT03768180 (http://clinicaltrials.gov/).

Prosthetic valve endocarditis caused by Pseudomonas aeruginosa with variable antibacterial resistance profiles: a diagnostic challenge

BackgroundInfective endocarditis (IE) caused by gram-negative bacilli is rare. However, the incidence of this severe infection is rising because of the increasing number of persons at risk, such as patients with immunosuppression or with cardiac implantable devices and prosthetic valves. The diagnosis of IE is often difficult, particularly when microorganisms such as Pseudomonas aeruginosa, which rarely cause this infection, are involved. One of the mainstays for the diagnosis of IE are persistently positive blood cultures with the same bacteria, while polymicrobial bacteremia usually points to another cause, e.g. an abscess. The antimicrobial resistance profile of some P. aeruginosa strains may change, falsely suggesting an infection with several strains, thus further increasing the diagnostic difficulties.Case presentationA 66-year old male patient who had a transcatheter aortic valve implantation (TAVI) one year previously developed fever seven days after an elective inguinal hernia repair. During the following four weeks, P. aeruginosa with different antibiotic resistance profiles was repeatedly isolated from blood cultures. Repeated trans-esophageal echocardiograms (TEE) were negative and an infection by different P. aeruginosa strains was suspected. Extensive diagnostic workup for an infectious focus was performed with no results. Finally, an oscillating mass on the aortic valve was detected by TEE five weeks after the initial positive blood cultures. P. aeruginosa endocarditis was confirmed by culture of the surgically removed valve. Whole genome sequencing of the last two P. aeruginosa isolates (valve and blood culture) revealed identical strains, with genome mutations for AmpR, AmpD and OprD.ConclusionsThe diagnosis of prosthetic valve endocarditis is particularly difficult for several reasons. The modified Duke criteria have a lower sensitivity for patients with prosthetic valve endocarditis and the infection may be caused by “unusual” pathogens such as P. aeruginosa. Patients with repeatedly positive blood cultures should make clinicians suspicious for endocarditis even if imaging studies are negative and if isolated pathogens are “unusual”. Repeatedly positive blood cultures for P. aeruginosa should be considered as “persistent bacteremia” (suspicious for IE) even in the presence of different antibiotic susceptibility patterns, since P. aeruginosa might rapidly activate or deactivate resistance mechanisms depending on antibiotic exposition.

Meta-analysis of 18F-FDG PET/CT in the diagnosis of infective endocarditis

BackgroundThe current diagnosis of infective endocarditis (IE) is based on the modified Duke criteria, which has approximately 80% sensitivity for the diagnosis of native valve endocarditis (NVE), with lower sensitivity for the diagnosis of prosthetic valve endocarditis (PVE) and culture-negative endocarditis. There is preliminary evidence that 18F-FDG PET/CT is an adjunctive diagnostic test with high accuracy reported in small studies to date. We therefore performed a meta-analysis of studies evaluating the use of PET/CT in the diagnosis of IE to establish a more precise estimate of accuracy. MethodsPubMed, Embase, Cochrane library, CINAHL, Web of Knowledge, and www.clinicaltrials.gov were searched from January 1990 to April 2017 for studies evaluating the accuracy of PET/CT for the evaluation of possible IE. ResultsWe identified 13 studies involving 537 patients that were included in the meta-analysis. The pooled sensitivity of PET/CT for diagnosis of IE was 76.8% (95% CI 71.8–81.4%; Q = 39.9, P < 0.01; I2 = 69.9%) and the pooled specificity was 77.9% (95% CI 71.9–83.2%; Q = 44.42, P < 0.01; I2 = 73.0%). Diagnostic accuracy was improved for PVE with sensitivity of 80.5% (95% CI 74.1–86.0%; Q = 25.5, P < 0.01; I2 = 72.5%) and specificity of 73.1% (95% CI 63.8–81.2%; Q = 32.1, P < 0.01; I2 = 78.2%). Additional extracardiac foci of infection were found on 17% of patients on whole body PET/CT. ConclusionPET/CT is a useful adjunctive diagnostic tool in the evaluation of diagnostically challenging cases of IE, particularly in prosthetic valve endocarditis. It also has the potential to detect clinically relevant extracardiac foci of infection, malignancy, and other sources of inflammation leading to more appropriate treatment regimens and surgical intervention.

Positron emission tomography for diagnosis of prosthetic valve endocarditis

Positron emission tomography for diagnosis of prosthetic valve endocarditis

18F-FDG PET/CT in the diagnosis of prosthetic valve endocarditis

18F-FDG PET/CT in the diagnosis of prosthetic valve endocarditis

Myocardial ischaemia as a result of external coronary compression from infective aortic root aneurysm: atypical presentation of prosthetic valve endocarditis

SummaryThis case describes an unusual presentation of prosthetic valve endocarditis (PVE): an acute coronary syndrome. A 67-year-old male presented with cardiac sounding chest pain on a background of a short history of night sweats, weight loss and general malaise. Four months previously, he had undergone bio-prosthetic aortic valve replacement for severe aortic stenosis and single vessel bypass grafting of the obtuse marginal. Whilst having chest pain, his ECG showed infero-lateral ST depression. Early coronary angiography revealed a new right coronary artery (RCA) lesion that was not present prior to his cardiac surgery. Using multi-modality cardiac imaging, the diagnosis of PVE was made. An aortic root abscess was demonstrated that was causing external compression of the RCA.

Comparable perioperative outcomes and mid-term survival in prosthetic valve endocarditis and native valve endocarditis.

Cardiac surgery for prosthetic valve endocarditis (PVE) represents one of the highest risk surgeries with in-hospital mortality of 20%. Given the complex nature of the operation, the operative outcome is likely strongly susceptible to the surgeon's experience and centre case volume, as measurements often are not apparent in large observational studies. We sought to evaluate operative outcomes and mid-term survival of patients with PVE compared with those of native valve endocarditis (NVE) at a tertiary care hospital. We conducted a single-institutional retrospective review of 188 consecutive patients (146 NVE and 42 PVE) undergoing cardiac surgery for endocarditis between 2011 and 2016 at a tertiary care hospital in the USA. A logistic regression model was fit to evaluate patient characteristics and perioperative outcomes in PVE and NVE: operative mortality and composite events (death, stroke, prolonged intubation, renal failure and sepsis). The Kaplan-Meier analysis was used to estimate the mid-term survival. The Cox proportional hazard model was fit to assess the adjusted risk associated with mid-term survival. Operative mortality was 4.1% for NVE and 0% for PVE (P = 0.34). Composite events occurred in 30.6% and 38.1% of NVE and PVE, respectively (P = 0.45). Multivariable logistic regression for composite events showed that PVE was not associated with increased risk of adverse events [odds ratio 1.4, 95% confidence interval (CI) 0.6-3.4; P = 0.49]. The Kaplan-Meier analysis demonstrated no statistically significant difference in survival (P = 0.99). Finally, the Cox proportional hazard analysis for mid-term mortality demonstrated that PVE was not associated with increased risk for hazard of death: hazard ratio 0.4, 95% CI 0.2-1.1; P = 0.085. Surgery for PVE can yield a low mortality rate with mid-term survival comparable with those of NVE. The diagnosis of PVE alone should not deter surgeons from operating on this complex patient population, provided that surgical expertise and experienced multidisciplinary team equipped to handle complex clinical scenarios are available.

ADVANCED IMAGING IN DIAGNOSING PROSTHETIC VALVE AND CARDIAC DEVICE INFECTIONS: A META-ANALYSIS

The diagnosis of prosthetic valve endocarditis (PVE) and infection of cardiac implantable electronic devices (CIED) is challenging. It is recognized that transthoracic echocardiography and trans esophageal echocardiography have limitations in evaluating infective endocarditis. Adding F-

The additional role of 18F-FDG PET/CT in prosthetic valve endocarditis.

The purpose of the present review is an update on the diagnosis of prosthetic valve endocarditis (PVE), evaluating the additional value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to the standard modified DUKE criteria on which for a long time is based the diagnostic strategy of the disease. We did a comprehensive research on the studies reported in the literature and regarding the employment of 18F-FDG PET/CT in the early diagnosis of PVE in patients with suspected disease. Scientific databases have been examined such as Medline and PubMed, followed by a review of citations and reference lists. The research included the following terms: infective endocarditis, prosthetic heart valve and cardiac valve replacement infections, 18F-FDG PET/CT and endocarditis. The recent studies reported in the literature on the PVE diagnostic approaches showed elevated sensitivity and specificity values of 18F-FDG PET/CT ranging from 73 to 96.6% and from 80 to 94%, respectively, reducing the number of misdiagnosed patients. The usefulness of the radioisotopic procedure is even more important when the other diagnostic conventional diagnostic tools, such as echocardiography, are inconclusive or negative in patients in whom the diagnosis of PVE is definitively ascertained. However, false negative and positive results of 18F-FDG PET/CT were also ascertained in some studies interfering with image interpretation even if such limitation can be reduced with an adequate patient preparation, with a better knowledge of clinical course of the disease, of the treatment in progress and of the different technical aspects of the method. In different studies reported in the literature, 18F-FDG PET/CT proved to improve the diagnostic accuracy of the conventional modified DUKE criteria in patients with suspected IE, and in particular with PVE, giving the highest diagnostic performance and providing additional diagnostic benefits. Thus, the radioisotopic hybrid procedure should be included in the diagnostic protocol of PVE as complementary tool to modified DUKE criteria. Finally, the usefulness of 18F-FDG PET/CT in monitoring the response to antibiotic therapy, although the few data reported in the literature are encouraging, needs more numerous studies and with a major number of cases.

18 F-Fluorodeoxyglucose Imaging of Inflammation

For >100 years,1 the diagnosis of endocarditis has been challenging, and this has been compounded by the increasing number of patients with prosthetic materials in the heart. The clinical challenge extends beyond accuracy because any delay in disease recognition inevitably postpones treatment planning and contributes to the high mortality rate that ranges between 14% and 22% during the hospitalization and ≤40% at 1-year follow-up.2 Current standards rely on the modified Duke criteria3 that catalogues clinical, imaging, microbiological, and pathological data into major and minor criteria so as to define a diagnostic probability classified as definite, possible, or unlikely with a sensitivity of ≈80%.4 Echocardiography (either transthoracic or transesophageal) represents an essential component in this process. However, despite its high resolution and wide applicability, ultrasound imaging is limited, particularly under 2 different conditions: in early disease stages, small structural alterations can be missed, whereas in postsurgical patients, the presence of composite material generates acoustic shadowing that may hamper diagnosis of prosthetic valve endocarditis (PVE),5 leading to inconclusive diagnosis in about 30% of patients.6 See Article by Mathieu et al To overcome this clinical uncertainty, single photon emission computed tomographic imaging of labeled leukocyte recruitment has been used for quite some time as a means to detect focal areas of infection.7,8 Overall consensus is that this technique is highly specific both in endocarditis of native structures and in PVE. However, the limited spatial resolution limits its diagnostic sensitivity even when single photon emission computed tomography is coregistered with computed tomography (CT). Radiolabeling of white blood cells also adds complexity to this procedure. Consequently, it tends to be used when other approaches remain inconclusive unless the question of endocarditis occurs in the early postsurgical phases, when the healing process impedes the analysis of other …