The valve uptake index: improving assessment of prosthetic valve endocarditis and updating [18F]FDG PET/CT(A) imaging criteria.

AIMS: Diagnosis of prosthetic valve endocarditis (PVE) by positron emission computed tomography angiography (PET/CTA) is based on visual and quantitative morpho-metabolic features. However, the fluorodeoxyglucose (FDG) uptake pattern can be sometimes visually unclear and susceptible to subjectivity. This study aimed to validate a new parameter, the valve uptake index [VUI, maximum standardized uptake value (SUVmax)-mean standardized uptake value (SUVmean)/SUVmax], designed to provide a more objective indication of the distribution of metabolic activity. Secondly, to re-evaluate the utility of traditionally used PVE imaging criteria and determine the potential value of adding the VUI in the diagnostic algorithm of PVE. METHODS AND RESULTS: Retrospective analysis of 122 patients (135 prosthetic valves) admitted for suspicion of endocarditis, with a conclusive diagnosis of definite (N = 57) or rejected (N = 65) PVE, and who had undergone a cardiac PET/CTA scan as part of the diagnostic evaluation. We measured the VUI and recorded the SUVmax, SUVratio, uptake pattern, and the presence of endocarditis-related anatomic lesions. The VUI, SUVmax, and SUVratio values were 0.54 ± 0.1 vs. 0.36 ± 0.08, 7.68 ± 3.07 vs. 3.72 ± 1.11, and 4.28 ± 1.93 vs. 2.16 ± 0.95 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%, 88%, and 86.7% and increased diagnostic ability for confirming endocarditis when combined with the standard diagnostic criteria. CONCLUSIONS: The VUI demonstrated good diagnostic accuracy for PVE, even increasing the diagnostic power of the traditionally used morphometabolic parameters, which also confirmed their own diagnostic performance. More research is needed to assess whether the integration of the VUI into the PVE diagnostic algorithm may clarify doubtful cases and thus improve the diagnostic yield of PET/CTA.

Risk-benefit Assessment of Systematic Thoracoabdominal-pelvic Computed Tomography in Infective Endocarditis.

BACKGROUND: In the management of infective endocarditis (IE), the presence of extracardiac complications has an influence on both diagnosis and treatment. Current guidelines suggest that systematic thoracoabdominal-pelvic computed tomography (TAP-CT) may be helpful. Our objective was to describe how systematic TAP-CT affects the diagnosis and the management of IE. METHODS: In this multicenter cohort study, between January 2013 and July 2016 we included consecutive patients who had definite or possible IE according to the Duke modified criteria, validated by endocarditis teams. We analyzed whether the Duke classification and therapeutic management were modified regarding the presence or the absence of IE-related lesion on CT and investigated the tolerance of this examination. RESULTS: Of the 522 patients included in this study, 217 (41.6%) had 1 or more IE-related lesions. On the basis of CT results in asymptomatic patients, diagnostic classification was upgraded from possible endocarditis to definite endocarditis for only 4 cases (0.8%). The presence of IE-related lesions on CT did not modify the duration of antibiotic treatment (P = .55), nor the decision of surgical treatment (P = .39). Specific treatment of the lesion was necessary in 42 patients (8.0%), but only 9 of these lesions (1.9%) were asymptomatic and diagnosed only on the TAP-CT. Acute kidney injury (AKI) within 5 days of CT was observed in 78 patients (14.9%). CONCLUSIONS: The TAP-CT findings slightly affected diagnosis and treatment of IE in a very small proportion of asymptomatic patients. Furthermore, contrast media should be used with caution because of the high risk of AKI.

Risk assessment for infected endocarditis in Staphylococcus aureus bacteremia patients: When is transesophageal echocardiography needed?

AIMS: Echocardiography is the main technique for the diagnosis of endocarditis in patients with Staphylococcus aureus bacteremia (SAB), but a consensus about performing transthoracic echocardiography or transesophageal echocardiography (TEE) as first-line tests is currently lacking. Recently, a new scoring system has been proposed by Palraj et al. to guide the use of TEE in this population. Our aim was to validate this scoring system or modify it, if necessary. METHODS AND RESULTS: Data from SAB patients admitted from 2012 to 2014 were collected. We tested the Palraj scores to stratify patients' risk for endocarditis. Moreover, we analyzed our population to identify any other possible clinical predictors of endocarditis not included in the score. Endocarditis was diagnosed in 38 of 205 patients (18.5%). Palraj's score was effective in the detection of patients at high risk of endocarditis. In addition, we identified the presence of cardiac devices, prolonged bacteremia and intravenous drug abuse (IVDA) as elements strongly correlated with endocarditis. Two scoring systems (Day-1 and Day-5) were derived including IVDA as a variable. Using a Day-1 cut-off value ≥5 and a Day-5 cut-off value ≥2, the 'modified Palraj's score' showed sensitivities of 42.1% and 97.0% and specificities of 88.6% and 32.0% for Day-1 and Day-5 scores, respectively. CONCLUSION: We modify and expand upon an effective scoring system to identify SAB patients at high risk for endocarditis in order to guide use of TEE. The inclusion of IVDA in the criteria for the calculation of the scores improves its effectiveness.

Two- and live/real time three-dimensional transthoracic echocardiographic assessment of infective endocarditis of a valved pulmonary conduit.

We describe the use of a nonstandard left infraclavicular approach in making the diagnosis of an infected valved conduit with two-dimensional transthoracic echocardiography. The patient was an adult with tetralogy of Fallot and pulmonary atresia who had undergone multiple surgical repair procedures. The initial diagnosis of infective endocarditis was made by transesophageal echocardiography. Both techniques demonstrated a single, large vegetation in the conduit. Live/real time three-dimensional transthoracic echocardiography, on the other hand, provided further information by demonstrating several additional vegetations in the conduit and more comprehensively assessed their size by enabling measurement of their azimuthal dimensions and volumes. The patient was treated with antibiotics with complete resolution of the vegetations.

Usefulness of real-time 3-dimensional echocardiography in the assessment of infective endocarditis: initial experience.

OBJECTIVE: Our aim was to provide an initial description of the usefulness of real-time 3-dimensional (3D) echocardiography when evaluating patients with infective endocarditis. METHODS: For this purpose, we describe 3 cases in which the usefulness of real-time 3D echocardiography is shown. RESULTS: Better definition of the morphologic characteristics of the vegetation and valvular apparatus was achieved with real-time 3D echocardiography. Furthermore, the information provided by the real-time 3D echocardiogram to the surgical team was accurate and direct because it was not based on detailed verbal information for performing a 3D mental reconstruction but was a simple image similar to what would be found in the operating room. In all cases, the information provided by the real-time 3D echocardiography was confirmed during surgery. CONCLUSIONS: Real-time 3D echocardiography is an important tool for aiding diagnosis or for fine tuning a suspected diagnosis when traditional echocardiography is not completely clear for both medical and surgical decision making.

Can structured clinical assessment using modified Duke's criteria improve appropriate use of echocardiography in patients with suspected infective endocarditis?

BACKGROUND: Although echocardiography has been incorporated into the diagnostic algorithm of patients with suspected infective endocarditis, systematic usage in clinical practice remains ill defined. OBJECTIVE: To test whether the rigid application of a predefined standardized clinical assessment using the Duke criteria by the research team would provide improved diagnostic accuracy of endocarditis when compared with usual clinical care provided by the attending team. METHODS: Between April 1, 2000 and March 31, 2001, 101 consecutive inpatients with suspected endocarditis were examined prospectively and independently by both teams. The clinical likelihood of endocarditis was graded as low, moderate or high. All patients underwent transthoracic echocardiography and appropriate transesophageal echocardiography if deemed necessary. All diagnostic and therapeutic outcomes were evaluated prospectively. RESULTS: Of 101 consecutive inpatients (age 50+/-16 years; 62 males) enrolled, 22% subsequently were found to have endocarditis. The pre-echocardiographic likelihood categories as graded by the clinical and research teams were low in nine and 37 patients, respectively, moderate in 83 and 40 patients, respectively, and high in nine and 24 patients, respectively, with only a marginal agreement in classification (kappa=0.33). Of the 37 patients in the low likelihood group and 40 in the intermediate group, no endocarditis was diagnosed. In 22 of 24 patients classified in the high likelihood group, there was echocardiographic evidence of vegetations suggestive of endocarditis. Discriminating factors that increased the likelihood of endocarditis were a prior history of valvular disease, the presence of an indwelling catheter, positive blood cultures, and the presence of a new murmur and a vascular event. General internists, rheumatologists and intensive care physicians were more likely to order echocardiography in patients with low clinical probability of endocarditis, of which pneumonia was the most common alternative diagnosis. CONCLUSION: Although prediction of clinical likelihood varies between observers, endocarditis is generally found only in those individuals with a moderate to high pre-echocardiographic clinical likelihood. Strict adherence to indications for transthoracic echocardiography and transesophageal echocardiography may help to facilitate more accurate diagnosis within the moderate likelihood category. Patients with low likelihood do not derive additional diagnostic benefit with echocardiography although other factors such as physician reassurance may continue to drive diagnostic demand.

Does assessment of pretest probability of disease improve the utility of echocardiography in suspected endocarditis in children?

OBJECTIVE: To compare the yield rate (YR) of echocardiography when evaluating children with suspected infectious endocarditis (IE) in both the actual clinical setting and in the hypothetic setting where strict clinical criteria are applied. Study design Medical records of 101 children undergoing echocardiography for suspected IE were reviewed. Echocardiograms with positive findings were identified and the actual diagnostic YR was calculated. With the use of clinical criteria proposed by von Reyn (VR), the probability of IE was retrospectively classified as (1) rejected, (2) possible, or (3) probable. Theoretic YR of echocardiography was calculated for each classification. RESULTS: The actual YR of echocardiography was 12% (12/101). The YR of echocardiography by VR class was 0% in rejected, 20% in possible, and 80% in probable cases (chi(2) = 55.1, P <.0001). Echocardiography did not change the probability of IE in any patient classified as rejected, but allowed reassignment of disease probability in a significant proportion of patients with possible or probable IE. CONCLUSIONS: The YR of echocardiography was significant when clinical probability of IE was intermediate-to-high, and low, with marginal clinical utility, when clinical probability was low. Strict pretest assessment of disease probability may lead to more effective utilization of echocardiography in this population.

Imaging techniques for diagnosis of infective endocarditis.

With the ability to structurally characterize cardiac manifestations, echocardiography is used for the diagnosis and management of infective endocarditis. In establishing the diagnosis according to the Duke criteria, the findings of endocardial involvement (vegetation, abscess, prosthetic valve dehiscence) or new valvular regurgitation represent "major" diagnostic criteria. As echocardiography cannot reliably differentiate noninfective from infective lesions, however, proper diagnosis lies in correlating echocardiography with clinical findings. The more invasive transesophageal approach provides substantially greater image resolution; this approach should be considered first in the evaluation of patients with higher prior probabilities of endocarditis and those with potential endocardial complications.

The role of transthoracic echocardiography in the diagnosis of infective endocarditis in children.

BACKGROUND: Infective endocarditis (IE) is frequently suspected but infrequently diagnosed in children. Clinicians often order echocardiograms to "rule out" IE. In an era of cost constraint, clinically efficient strategies must be developed to eliminate unnecessary tests. We hypothesized that transthoracic echocardiography (TTE) is only useful in children in whom there is a high clinical suspicion of IE based on history, physical examination, and persistently positive blood cultures. OBJECTIVE: To determine the role of TTE as a screening test for suspected IE in children. METHODS: Echocardiographic reports and medical records were reviewed retrospectively for 173 consecutive patients who underwent TTE to rule out IE from January 1993 to August 1996. RESULTS: Persistent fever was the predominant symptom leading to a suspicion of IE (120 patients [69.4%]). Fifty-seven (32.9%) of the 173 patients had congenital heart disease and 95 patients (54.9%) had indwelling venous catheters. Twenty-six patients (15.0%) were diagnosed and treated for IE. Twelve (46.2%) of these 26 patients had vegetations seen on TTE. The conditions of the remaining 14 patients were diagnosed clinically and these patients had persistently positive blood cultures. By univariate analysis, the risk factors associated with the diagnosis of IE were malaise, congestive heart failure, new or changing heart murmur, leukocytosis, hematuria, and the presence of 2 or more positive blood cultures for the same organism. The risk factors associated with positive TTE were malaise, congestive heart failure, new or changing heart murmur, leukocytosis, hematuria, and 2 or more positive blood cultures. The presence of an indwelling catheter or immunocompromised status were not predictive of vegetation or IE. CONCLUSIONS: Transthoracic echocardiography has poor sensitivity as a screening test for IE in patients with low clinical probability of the disease. A diagnostic algorithm for IE is suggested based on these data.

Echocardiography in patients with suspected endocarditis: a cost-effectiveness analysis.

PURPOSE: We sought to determine the appropriate use of echocardiography for patients with suspected endocarditis. PATIENTS AND METHODS: We constructed a decision tree and Markov model using published data to simulate the outcomes and costs of care for patients with suspected endocarditis. RESULTS: Transesophageal imaging was optimal for patients who had a prior probability of endocarditis that is observed commonly in clinical practice (4% to 60%). In our base-case analysis (a 45-year-old man with a prior probability of endocarditis of 20%), use of transesophageal imaging improved quality-adjusted life expectancy (QALYs) by 9 days and reduced costs by $18 per person compared with the use of transthoracic echocardiography. Sequential test strategies that reserved the use of transesophageal echocardiography for patients who had an inadequate transthoracic study provided similar QALYs compared with the use of transesophageal echocardiography alone, but cost $230 to $250 more. For patients with prior probabilities of endocarditis greater than 60%, the optimal strategy is to treat for endocarditis without reliance on echocardiography for diagnosis. Patients with a prior probability of less than 2% should receive treatment for bacteremia without imaging. Transthoracic imaging was optimal for only a narrow range of prior probabilities (2% or 3%) of endocarditis. CONCLUSION: The appropriate use of echocardiography depends on the prior probability of endocarditis. For patients whose prior probability of endocarditis is 4% to 60%, initial use of transesophageal echocardiography provides the greatest quality-adjusted survival at a cost that is within the range for commonly accepted health interventions.

Acute aortic endocarditis with annular destruction: assessment of surgical treatment with cryopreserved valvular homografts.

BACKGROUND AND AIM OF THE STUDY: Valve ring abscesses in acute infective aortic endocarditis have a low, though not insignificant, prevalence. Surgical treatment with implantation of prosthetic valves may lead to major life-threatening complications, such as recurrent endocarditis and partial or complete prosthetic dislocation. Valvular homografts may offer a higher resistance to recurrent infection and have thus become recognized as an excellent and safe substitute for orthotopic left ventricular outflow reconstruction. METHODS: Between May 1991 and July 1996, 25 patients underwent surgical treatment for aortic endocarditis with annular destruction. Staphylococcus spp. were present in 32% of patients and Streptococcus spp. in 48%. Seven aortic valve replacements (AVR) and 18 aortic root replacements (ARR) were performed using cryopreserved valvular homografts. All grafts were implanted in the subannular position. RESULTS: The overall outcome was good in 23 patients, two died in the early postoperative period. Mean follow up was 38 +/- 18 months (range: 14 to 76 months). No recurrence of endocarditis was detected and no significant alterations of the implants were described. Transvalvular gradients were significantly lower in ARR patients than in AVR patients. CONCLUSIONS: Despite the severity of the tissue damage, cryopreserved homografts, when implanted in the subannular position, constitute a safe and reproducible surgical treatment of aortic endocarditis with annular involvement.

Cost-effectiveness of transesophageal echocardiography to determine the duration of therapy for intravascular catheter-associated Staphylococcus aureus bacteremia.

BACKGROUND: The appropriate duration of therapy for catheter-associated Staphylococcus aureus bacteremia is controversial. Conventional practice dictates that all patients receive prolonged courses of intravenous antibiotics. Some clinicians recommend abbreviated therapeutic courses, but an alternate approach involves prospectively identifying patients for whom abbreviated therapy is appropriate. OBJECTIVE: To determine the cost-effectiveness of transesophageal echocardiography (TEE) in establishing duration of therapy for catheter-associated S. aureus bacteremia. DESIGN: Cost-effectiveness analysis. DATA SOURCES: MEDLINE search of literature; clinical data from patients with S. aureus bacteremia (n = 196) and patients with endocarditis (n = 60); and costs obtained from the study institution, regional home health agency, and national estimates of professional and technical fees. TARGET POPULATION: Patients with catheter-associated S. aureus bacteremia on native heart valves without intravenous drug use or clinically apparent metastatic infection, immunosuppression, or indwelling prosthetic devices. TIME HORIZON: Patient lifetime. PERSPECTIVE: Societal. INTERVENTIONS: Antibiotic treatment based on TEE results compared with 2- or 4-week empirical therapy. OUTCOME MEASURES: Quality-adjusted life expectancy, costs, and incremental cost-effectiveness ratios. RESULTS OF BASE-CASE ANALYSIS: Compared with empirical short-course therapy, the TEE strategy cost $4938 per quality-adjusted life-year (QALY) gained. The effectiveness of the TEE strategy and the effectiveness of the long-course strategy were sufficiently similar that the additional cost of empirical long-course therapy ($1,667,971 per QALY) was higher than that which society usually considers cost-effective. RESULTS OF SENSITIVITY ANALYSES: In a four-way sensitivity analysis (endocarditis prevalence, TEE cost, short-course relapse rate, and TEE specificity), compared with empirical short-course therapy, the TEE strategy results ranged from cost savings to $155,624 per QALY. CONCLUSION: Within the limitations of existing empirical data, this study suggests that for patients with clinically uncomplicated catheter-associated S. aureus bacteremia, the use of TEE to determine therapy duration is a cost-effective alternative to 2- or 4-week empirical therapy.

Gonococcal endocarditis: assessment by transesophageal echocardiography.

Gonococcal endocarditis is a rare but aggressive infection that has an alarming rate of perivalvular abscess and mortality. We present a case of gonococcal endocarditis with intracardiac abscess and fistula diagnosed by transesophageal echocardiography. Given the often acute nature of gonococcal endocarditis and its propensity toward abscess formation, transesophageal echocardiography should be considered early in the course of this infection.

Transesophageal echocardiographic assessment of embolic sources: intracardiac and extracardiac masses and aortic degenerative disease.

The increased sensitivity of transesophageal echocardiography (TEE) makes it complementary and, in many cases, superior to transthoracic echocardiography in the detection of various sources of embolism. These sources include intracardiac thrombus, tumors, spontaneous echocardiographic contrast, and others. TEE is also helpful as an adjunctive test for the diagnosis of pulmonary embolisms.