Echocardiography in infective endocarditis: reassessment of prognostic implications of vegetation size determined by the transthoracic and the transesophageal approach

Clinical features remain important for the diagnosis of infective endocarditis in the modern era

BACKGROUND

Infective endocarditis (IE) can be difficult to diagnose, due to multiple (often non-specific) presenting features.

AIM

To assess the predictive accuracy of classical clinical features and blood investigations readily available at the time of presentation.

DESIGN

Cross-sectional analysis.

METHODS

We studied 29 IE cases and 79 controls (clinically suspicious contemporaneous cases where IE was subsequently excluded) from a hospital-based group of patients referred to a cardiac department with possible infective endocarditis. Patients were identified from the echocardiography database. Cases were defined by final diagnosis. Symptoms, signs, risk factors for IE and blood investigations were recorded from case notes and examined by univariate and multivariate analyses.

RESULTS

The sensitivity, specificity, and positive and negative predictive values of transthoracic echocardiography (TTE) for detection of IE in clinically suspected cases were 71%, 98%, 57% and 99%, respectively. Univariate analyses revealed a significant association between IE and several clinical features. Under multivariate analysis, previous heart valve surgery (OR 13.3, 90%CI 3.2-55.6), positive blood cultures (OR 17.2, 90%CI 4.9-58.8), signs of embolism (OR 11.4, 90%CI 3.0-43.5), a new, altered or changing murmur (OR 10.3, 90%CI 2.8-38.5) and splenomegaly (OR 18.2, 90%CI 3.6-90.9) were independent predictors for IE.

DISCUSSION

Clinical features at presentation continue to be important for the diagnosis of IE. Features such as positive blood cultures, signs of embolism and a changing heart murmur should be used to guide investigation and treatment of IE prior to echocardiography, or when TTE is negative.

Analysis of mortality and risk factors associated with native valve endocarditis in drug users: the importance of vegetation size

BACKGROUND

Native valve endocarditis in drug-user patients had a microbiology, a frequency of involvement of different cardiac valves, and a prognosis that differ from those in non-drug users. A retrospective study of native valve endocarditis cases in intravenous drug users diagnosed from 1985 to 1999 in our institution was performed to analyze the inhospital mortality of drug users with native valve endocarditis and to identify factors predictive of mortality.

METHODS

All patients fulfilled the Duke's criteria for definite or probable endocarditis. Analysis of predictors of inhospital mortality was restricted to right-sided infective endocarditis (IE) with definite diagnosis and echocardiographic data. The following variables were analyzed: sex, HIV serostatus, CD4 cell count < 200/mm3, time of IE diagnosis (before 1993 or after 1993), previous valvulopathy, polymicrobial IE, fungal etiology (mixed or alone), neurological complication, arterial emboli, pulmonary emboli, congestive heart failure, vegetation size (VS) > 2 cm, and inhospital cardiac surgery. Logistic regression was used in a multivariate model to identify factors independently associated with mortality. Adjusted odds ratios (OR) and 95% CIs were examined.

RESULTS

Four hundred ninety-three cases of IE were diagnosed in this period. Two hundred twenty cases of native valve endocarditis in intravenous drug users were identified. Fourteen cases in this group died (6%). Mean time from diagnosis to death was 18.5 +/- 15 days (range, 3-52). Vegetation size was available in 111 cases. Univariate analysis identified the following variables associated with inhospital mortality in right-sided cases: VS > 2 cm and fungal etiology. In multivariate analysis, the variables associated with mortality that achieved statistical significance were size of vegetation > 2 cm (P = .014, OR 10.2, 95% CI 1.6-78.0) and fungal etiology (P = .009, OR 46.2, 95% CI 2.4-1100.9).

CONCLUSIONS

The main prognostic factors of inhospital mortality in right-sided IE in drug users in our series were VS > 2 cm and fungal etiology. The role of early surgery in these patients should be reevaluated.

The use and effect of surgical therapy for prosthetic valve infective endocarditis: a propensity analysis of a multicenter, international cohort

BACKGROUND

Although surgical intervention is often used in the treatment of prosthetic valve infective endocarditis (PVIE), an understanding of its effect on survival has been limited by the biases of observational studies and lack of controlled trials.

METHODS

The International Collaboration on Endocarditis Merged Database is a large, multicenter, international registry of patients with definite endocarditis by Duke criteria, including 367 patients with PVIE. Clinical, microbiologic, and echocardiographic variables were analyzed to determine those factors associated with the use of surgery for PVIE. Logistic regression analysis was performed to create a propensity model of predictors of surgery use. Patients who underwent surgery during initial hospitalization were matched by propensity score with patients treated with medical therapy alone. Logistic regression analysis was performed to determine variables independently associated with inhospital mortality in this matched subset.

RESULTS

Surgical therapy for PVIE was performed in 148 (42%) of 367 patients. Inhospital mortality was similar for patients treated with surgery compared with those treated with medical therapy alone (25.0% vs 23.4%, P = .729). Surgical therapy was independently associated with patient age, microorganism, intracardiac abscess, and congestive heart failure. After adjustment for these determinants, inhospital mortality was predicted by brain embolization (OR 11.12, 95% CI 4.16-29.73) and Staphylococcus aureus infection (OR 3.67, 95% CI 1.29-9.74), with a trend toward benefit for surgery (OR 0.56, 95% CI 0.23-1.36).

CONCLUSIONS

Despite the frequent use of surgery for the treatment of PVIE, this condition continues to be associated with a high inhospital mortality rate in the contemporary era. After adjustment for factors related to surgical intervention, brain embolism and S aureus infection were independently associated with inhospital mortality and a trend toward a survival benefit of surgery was evident.

Risk of Embolism and Death in Infective Endocarditis: Prognostic Value of Echocardiography

Background— The incidence of embolic events (EE) and death is still high in patients with infective endocarditis (IE), and data about predictors of these 2 major complications are conflicting. Moreover, the exact role of echocardiography in risk stratification is not well defined.

Methods and Results— In a multicenter prospective European study, including 384 consecutive patients (aged 57±17 years) with definite IE according to Duke University criteria, we tested clinical, microbiological, and echocardiographic data as potential predictors of EE and 1-year mortality. Transesophageal echocardiography was performed in all patients. Embolism occurred before or after IE diagnosis (total-EE) in 131 patients (34.1%) and after initiation of antibiotic therapy (new-EE) in 28 patients (7.3%). Staphylococcus aureus and Streptococcus bovis were independently associated with total-EE, whereas vegetation length >10 mm and severe vegetation mobility were predictors of new-EE, even after adjustment for S aureus and S bovis . One-year mortality was 20.6%. In multivariable analysis, independently of the other predictors of death (age, female sex, creatinine serum >2 mg/L, moderate or severe congestive heart failure, and S aureus ) and comorbidity, vegetation length >15 mm was a predictor of 1-year mortality (adjusted relative risk=1.8; 95% CI, 1.10 to 2.82; P =0.02).

Conclusions— In IE, vegetation length is a strong predictor of new-EE and mortality. In combination with clinical and microbiological findings, echocardiography may identify high-risk patients who will need a more aggressive therapeutic strategy.

Embolic risk in subacute bacterial endocarditis: Determinants and role of transesophageal echocardiography

Embolic events are a frequent and life-threatening complication of subacute bacterial endocarditis (SBE) and are associated with a high mortality and morbidity. The prediction of the embolic risk in an individual patient remains a challenge. Echocardiography plays a key role in the management of infective endocarditis both for the diagnostic and prognostic assessment of these patients, but its value in predicting embolic events is still debated. This review focuses on the characteristics of embolic events in SBE, and on the role of echocardiography, especially transesophageal echocardiography (TEE), in the prediction of embolic events. The review confirms that, among other factors, TEE may be helpful in both the prediction of the embolic risk and the decision to perform early surgery.

Infective endocarditis and acute purulent pericarditis in a patient with hyperglycemia

A diabetic patient was admitted to our hospital for infective endocarditis with acute purulent pericarditis and diabetic ketoacidosis. Echocardiography revealed attachment of vegetation to the chordae tendineae in the left ventricle and pericaridial effusion. The vegetation was enlarged and pendulated for a few days despite maximal antimicrobial therapy. Surgical resection was desirable to decrease the risk of embolic complications and cardiovascular collapse. We could not open the heart because of accumulation of purulent pericardial fluid, and right renal infarction was complicated. We believe that the immunocompromised and hypercoagulable state due to diabetes caused these conditions.

Impact of harmonic imaging on transthoracic echocardiographic identification of infective endocarditis and its complications

OBJECTIVE

To evaluate the comparative diagnostic value of harmonic imaging (HI) in the assessment of patients with suspected infective endocarditis (IE).

SETTING

Tertiary referral centre.

DESIGN

139 consecutive patients were evaluated with three imaging modalities: transthoracic echocardiography with fundamental imaging (FI); HI; and transoesophageal echocardiography (TOE). Image quality was assessed for each modality by semiquantitative scoring (0, poor, to 3, excellent). Presence, dimension, and characteristics of vegetations were assessed separately for each imaging modality, as well as presence of abscesses.

RESULTS

35 patients had definite IE. TOE was positive in 33 patients, HI in 28, and FI in 12 (p < 0.001 for FI v HI and v TOE). Mean image quality was 1.4 (0.7) for FI, 2.1 (0.6) for HI (p < 0.01 v FI), and 2.6 (0.4) for TOE (p < 0.001 v HI). The association between FI and TOE findings was Phi = 0.35 (chi2 = 17.57, p = 0.0014) and between HI and TOE it was Phi = 0.95 (chi2 = 125.72, p < 0.0001; p < 0.0001 v FI). The global echo score of vegetations was 7.1 (3.3) with FI, 8.5 (3.4) with HI, and 11.3 (3.9) with TOE (p < 0.001 v HI). Compared with TOE, FI identified only one of seven abscesses (sensitivity 14%) and HI identified two of seven abscesses (sensitivity 28%).

CONCLUSIONS

HI provides an accurate assessment of suspected IE. TOE achieves superior definition of IE related abnormalities.

Adult Echocardiography and Doppler

One of the first reports of cardiac ultrasound imaging occurred in 1954 by Elder and Hertz. They described the use of ultrasound imaging for displaying continuous recording of movement of heart walls. This was displayed by the use of A-mode and B-mode methods. In the late 1950s, continuous-wave Doppler was used in cardiac imaging. By the late 1960s, two-dimensional real-time B-mode imaging was performed using mechanical head transducers. In the mid-1970s, phased array transducers were being utilized. Also in the late 1970s, transesophageal echo was being tested. The 1980s have seen advances in computer technology that have made color flow Doppler imaging possible, along with better image quality through scan conversion and image processing. In the 1990s developing techniques included stress echocardiography, intravascular ultrasound, contrast echocardiography, digital acquisition, second harmonic imaging, ultrasonic tissue characterization, and three-dimensional echocardiography. More recently, echocardiography has seen advances in real-time 3D imaging, handheld echocardiography, and myocardial perfusion. Advances in technology, along with improved understanding of the equipment, have made the availability and demand of echocardiography invaluable.

Chronic cor pulmonale: a rare complication of undiagnosed pacemaker lead endocarditis

Pacemaker lead infection is a rare life-threatening complication of permanent transvenous pacing. We describe the case of a young man who suffered recurrent undiagnosed septic pulmonary embolisms from pacemaker lead vegetations inducing chronic cor pulmonale with major pulmonary arterial hypertension. The potential complications of transvenous pacing and the systematic use of transesophageal echocardiography are emphasized.

Early predictors of in-hospital death in infective endocarditis

BACKGROUND

Data on early determinants of outcome in infective endocarditis (IE) are limited. We evaluated the prognostic significance of early clinical characteristics in a large, prospective cohort of patients with IE.

METHODS AND RESULTS

Two hundred sixty-seven consecutive patients with definite or possible IE by modified Duke criteria and echocardiography performed within 7 days of presentation were evaluated. Acute physiology was assessed by the Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) score at the time of presentation, and early heart failure was diagnosed by Framingham criteria. In-hospital mortality rate in the cohort was 19% and similar for patients with definite or possible IE (20% versus 16%, respectively; P=0.464). Independent predictors of death determined by logistic regression modeling were diabetes mellitus (OR 2.48; 95% CI, 1.24 to 4.96), Staphylococcus aureus as causative organism (OR, 2.06; 95% CI, 1.01 to 4.20), APACHE II score (OR, 1.07; 95% CI, 1.01 to 1.12), and embolic event (OR, 2.79; 95% CI, 1.15 to 6.80). Early echocardiographic findings of the Duke criteria were not predictive of death.

CONCLUSIONS

Early in the course of IE, readily available clinical characteristics that reflect the host-pathogen interaction are predictive of in-hospital death. These factors may identify those patients with IE for more aggressive treatment.

Risk factors for systemic emboli in infective endocarditis

A retrospective study was undertaken to analyse the risk factors for systemic emboli in infective endocarditis. Patients (n = 80; 70% males; mean age 65 years; range 20-91 years) with infective endocarditis, as defined by the Duke criteria and diagnosed using transoesophageal echocardiography during the period January 1995 to March 2001, were included. The average time between the start of the illness and the beginning of antibiotic treatment was 55 days (range 0-405 days). The pathogens identified were streptococci (n = 47), staphylococci (n = 11), enterococci (n = 9), and others (n = 4). In nine cases, blood cultures were sterile. Thirty patients with at least one embolic episode were compared with 50 control patients. According to univariate analysis, the main risk factor for systemic emboli was the size of the vegetation (12.4 mm vs. 7.8 mm; p = 0.0005). The risk of emboli was 57% when the vegetation measured > 10 mm and only 22% when it was < 10 mm (p = 0.003). The mobility of the vegetation was also a risk factor: 48% if the vegetation was mobile; and 9% if fixed (p = 0.003). Sex, age, pathogen, antibiotic treatment, type of valve and the number and position of the vegetations were not found to be risk factors. With multivariate analysis, only mobility was identified as a risk factor. Overall, mobile vegetations > 10 mm in size were associated with an increased risk of embolic episodes in infective endocarditis.

Stroke location, characterization, severity, and outcome in mitral vs aortic valve endocarditis

OBJECTIVE

To characterize the incidence and clinical features of patients with infective endocarditis (IE) and stroke.

METHODS

The authors reviewed the records of 707 patients diagnosed with definite or possible IE between January 1984 and November 1999. Stroke was confirmed by application of strict definitions and classified by type, pathophysiology, vascular territory, and severity. The authors determined mortality rates for the initial hospitalization and 12 months after admission.

RESULTS

Strokes occurred in 68 (9.6%) of 707 patients with IE, 38 (17%) of 218 patients with mitral valve endocarditis (MVE), 14 (9%) of 149 patients with aortic valve endocarditis (AVE), and 16 (5%) of 340 patients with other forms of IE (OR for MVE vs AVE = 2.0, 95% CI 1.1 to 3.9). Among the patients with MVE or AVE and stroke, there were no significant relationships between site of vegetation and length of hospitalization, stroke severity, mortality during the initial hospitalization, or 12-month mortality. Fifty-two percent of patients with stroke and IE died within 1 year of admission.

CONCLUSIONS

The overall incidence of stroke in patients with IE (9.6%) is lower than previous reports (21 to 39%). Patients with MVE had a greater risk of stroke than patients with AVE. Fifty-two percent of patients died within 1 year of admission for IE.

A randomized trial of aspirin on the risk of embolic events in patients with infective endocarditis

OBJECTIVES

This study examined the effect of aspirin on the risk of embolic events in infective endocarditis (IE).

BACKGROUND

Embolism is a major complication of IE, and studies in animal models have shown that platelet inhibition with aspirin can lead to more rapid vegetation resolution and a lower rate of embolic events.

METHODS

We conducted a randomized, double-blinded, placebo-controlled trial of aspirin treatment (325 mg/day) for four weeks in patients with IE to test the hypothesis that the addition of aspirin would reduce the incidence of clinical systemic embolic events. Patients with perivalvular abscess were excluded. Serial cerebral computed tomograms and transesophageal echocardiograms were obtained in a subset of patients.

RESULTS

During the four-year study period, 115 patients were enrolled: 60 assigned to aspirin and 55 assigned to placebo. Embolic events occurred in 17 patients (28.3%) on aspirin and 11 patients (20.0%) on placebo, with an odds ratio (OR) of 1.62 (95% confidence interval [CI] 0.68 to 3.86, p = 0.29). There was a trend toward a higher incidence of bleeding in the patients taking aspirin versus placebo (OR 1.92, 95% CI 0.76 to 4.86, p = 0.075). Development of new intracranial lesions was similar in both groups. Aspirin had no effect on vegetation resolution and valvular dysfunction.

CONCLUSIONS

In endocarditis patients already receiving antibiotic treatment, the addition of aspirin does not appear to reduce the risk of embolic events and is likely associated with an increased risk of bleeding. Aspirin is not indicated in the early management of patients with IE.

Overview of transesophageal echocardiography for the chest physician

Transesophageal echocardiography (TEE) is a growing technology that is frequently utilized in the critical care setting by intensivists, surgeons, anesthesiologists as well as specialists in cardiovascular diseases. The clinical application of TEE continues to emerge, and the indications and diagnostic utility of this technology as currently available are summarized in this review.

Endocardial pacemaker or defibrillator leads with infected vegetations: a single-center experience and consequences of transvenous extraction

BACKGROUND

Removal of infected endovascular leads if often required for cure of systemic infection, but the perceived risk of embolic events in the presence of large (>10 mm) vegetations has been considered a relative contraindication to transvenous removal. Surgical removal of pacemaker leads has been suggested in this situation to avoid occurrence of pulmonary embolization.

METHODS

Of 38 patients with infection of implanted pacemaker or cardioverter-defibrillator devices, those with evidence for systemic infection underwent transesophageal echocardiography to assess for the presence of vegetations.

RESULTS

Vegetations on endocardial leads or right-sided cardiac structures ranging in size from 10 mm to 38 mm in their largest dimension were detected in 9 patients. All patients underwent successful transvenous removal of endocardial leads. Five of 9 patients (55%) had evidence of pulmonary embolism. However, all 5 patients made a full recovery with antibiotic treatment and anticoagulation. Among patients with endocardial vegetations, there was no difference in hospitalization periods between those with or without pulmonary embolism (14.6 +/- 0.8 days vs 18.0 +/- 4.5 days, P =.7).

CONCLUSIONS

Transvenous removal of infected pacemaker leads is an alternative to open-thoracotomy removal of infected leads. Fifty-five percent of patients with vegetations on endocardial leads in our series experienced pulmonary embolism, but neither survival nor length of hospital stay were affected by this complication.

Risk factors for "major" embolic events in hospitalized patients with infective endocarditis

BACKGROUND

Infective endocarditis often is complicated by embolic events after hospital admission. Identifying patients at higher risk may improve the disease outcome. This study was aimed at identifying predictors of embolic risk among the clinical and laboratory data obtained on hospital admission in patients diagnosed as having definite infective endocarditis according to the Duke criteria.

METHODS

Ninety-four patients were enrolled in a prospective study. The results of hematologic, echocardiographic, and microbiological investigations were analyzed, using statistical methods as appropriate. Multivariate analysis was applied to variables significantly associated with embolism in univariate analysis.

RESULTS

Forty-six percent of patients had a major embolic complication after admission. No association was found between embolism and sex, site of infection, or microorganism involved. Patients with embolism were significantly younger, had larger vegetation, and showed a significantly higher level of serum C-reactive protein and lower albumin concentrations than those without embolism. Young age, larger vegetation size, and high levels of C-reactive protein were the independent variables associated with an increased incidence of embolic events in the multivariate logistic regression analysis.

CONCLUSIONS

Our data indicate that patients with infective endocarditis with young age and/or with large vegetation and/or with high serum levels of C-reactive protein are at increased risk of major embolic complications during the in-hospital course of the disease.

Culture-negative suppurative endocarditis causing severe mitral valve obstruction: complementary use of transesophageal and transthoracic echocardiography

Infective endocarditis causes a myriad number of serious complications. Mitral valve obstruction is a rare complication. We report a 48-year-old Asian female who presented with two-week duration of fever and rapidly developed acute pulmonary edema and cardiogenic shock. Sequential transthoracic and transesophageal echocardiography revealed a rapidly growing vegetation on the anterior mitral leaflet with severe stenosis of the valve. All the blood cultures were negative. The patient underwent a successful mitral valve replacement. A review of 21 previously reported cases of mitral valve obstruction from endocarditis demonstrates the poor prognosis of this entity and supports early surgery.

[Predictors of hospital mortality in 186 cases of active infective endocarditis treated in a tertiary medical center (1992-2001)]

INTRODUCTION AND OBJECTIVES

The aim of this study was to describe the predictors of hospital mortality found in patients admitted for infective endocarditis (IE) to a cardiovascular surgery ward. Patients and method. Prospective study of 186 patients with IE treated in our hospital between 1992 and 2001.

RESULTS

One hundred fourteen patients (61.3%) had native valve endocarditis and 72 (38.7%) had prosthetic valve endocarditis (early in 28 patients [up to 12 months after surgery] and late in 44 [later than 12 months]). Blood cultures were positive in 82%. The predominant organism was Streptococcus viridans (36%) in native valve endocarditis and Staphylococcus aureus (33%) in prosthetic valve endocarditis. The hospital mortality was 22.6%. Severe sepsis (4.8%) produced a high mortality rate (88%) and was caused by Staphylococcus aureus in 60%. One hundred nineteen patients (64%) required surgery, 79 (66.4%) of them urgently. Negative blood cultures predicted need for surgery in native valve endocarditis (p < 0.05). The surgical mortality was 21.8% and was related to NYHA III-IV class (p = 0.014) and emergency surgery (p = 0.009) in patients with native valve endocarditis. This last factor also predicted higher surgical mortality in patients with early prosthetic valve endocarditis (p < 0.001).

CONCLUSIONS

The hospital mortality of this group of patients with infective endocarditis treated in a tertiary medical center was high. The presence of severe sepsis, although infrequent, had a somber prognosis. Severe heart failure in native valve endocarditis and urgent surgery in native and prosthetic valve endocarditis increased surgical mortality.

Current best practices and guidelines. Assessment and management of complications in infective endocarditis

The most important complications of endocarditis are congestive heart failure, paravalvular abscess formation, and embolism, especially stroke. In addition, endocarditis may be complicated by septic arthritis, vertebral osteomyelitis, pericarditis, metastatic abscesses and an array of renal problems ranging from immune-complex glomerulonephritis to renal abscesses. Adverse reactions associated with medical treatment of endocarditis can also result in significant complications such as ototoxicity and nephrotoxicity, skin rashes, and serum sickness. This review focuses on the cardiac, embolic, neurologic and renal complications of endocarditis and discusses how these complications influence the clinical management of individual cases in daily practice.

Infective endocarditis and cardiac surgery in intravenous drug abusers and HIV-1 infected patients

Infective endocarditis (IE) is one of the most severe complications of parenteral drug abuse. The incidence of IE in intravenous drug abusers (IVDAs) is 2% to 5% per year, being responsible for 5% to 10% of the overall death rate. The prevalence of HIV infection among IVDAs with IE ranges between 30% and 70% in developed countries and HIV-infection by itself increases the risk of IE in IVDAs. The incidence of IE in IVDAs is currently decreasing in some areas, probably due to changes in drug administration habits by addicts to avoid HIV transmission. Overall, Staphylococcus aureus is the most common etiological agent, being usually sensitive to methicillin (MSSA). The tricuspid valve is the most frequently affected (60% to 70%), followed by the mitral and aortic valves (20% to 30%). HIV-positive IVDAs have a higher ratio of right-sided IE and S aureus IE than HIV-negative IVDAs. Response to antibiotic therapy is similar. Drug addicts with non-complicated MSSA right-sided IE can be treated with an i.v. short-course regimen of nafcillin or cloxacillin for 2 weeks, with or without addition of an aminoglycoside during the first 3 to 7 days. The prognosis of right-sided endocarditis is generally good; overall mortality is less than 5%, and with surgery is less than 2%. In contrast, the prognosis of left-sided IE is less favorable; mortality is 20% to 30%, and even with surgery is 15% to 25%. IE caused by GNB or fungi has the worst prognosis. Mortality between HIV-infected or non-HIV-infected IVDAs with IE is similar. However, among HIV-infected IVDAs, mortality is significantly higher in those who are most severely immunosuppressed, with CD4+ cell count < 200/microL or with AIDS criteria. Conversely, IE in HIV-infected patients who are not drug abusers is rare. The epidemiology of cardiac surgery in IVDAs and/or HIV-infected patients has changed in recent years. There is a decrease in IE and an increase of patients undergoing surgery (CABS) for coronary artery disease secondary to the hyperlipidemia and lipodystrophy induced by highly active antiretroviral therapy (HAART). Cardiac surgery in HIV-infected patients with or without IE does not worsen the prognosis because extracorporeal circulation did not affect the immune status after surgery. Morbidity and mortality seems to stay within the same range as the non-infected patients. In our experience, in the IE in HIV-infected IVDA group, the 1-year survival is 65% and the 5 and 10-year actuarial survival is 35%. For patients operated on for coronary artery disease, the 5-year survival is 100%.

Embolic risk in subacute bacterial endocarditis: determinants and role of transesophageal echocardiography

Embolic events are a frequent and life-threatening complication of subacute bacterial endocarditis (SBE), and are associated with a high mortality and morbidity. The prediction of the embolic risk in an individual patient remains a challenge. Echocardiography plays a key role in the management of infective endocarditis both for the diagnostic and prognostic assessment of these patients, but its value in predicting embolic events is still debated. This review focuses on the characteristics of embolic events in SBE, and on the role of echocardiography, especially transesophageal echocardiography (TEE), in the prediction of embolic events. The review confirms that, among other factors, TEE may be helpful in both the prediction of the embolic risk, and the decision to perform early surgery.

Clinical criteria and the appropriate use of transthoracic echocardiography for the exclusion of infective endocarditis

BACKGROUND

Clinical guidelines currently suggest that transthoracic echocardiography (TTE) be carried out in all patients with suspected endocarditis, but the use of TTE where there is a low probability of infective endocarditis has a poor diagnostic yield. This screening approach may no longer be appropriate.

OBJECTIVE

To examine whether clinical criteria might aid decision making with respect to the use of TTE in possible endocarditis.

DESIGN

A retrospective review of patient records.

SETTING

Cardiology department of a tertiary referral centre.

PATIENTS

500 consecutive hospital inpatients referred for TTE to exclude endocarditis.

MAIN OUTCOME MEASURES

Evidence of endocardial vegetations on TTE and the presence of predetermined clinical criteria that may predispose to, or be suggestive of, endocarditis.

RESULTS

Evidence of infective endocarditis was detected on echocardiography in 43 of the 500 patients (8.6%). In 239 patients (48%), vegetations and certain prespecified clinical criteria were both absent. These criteria were: vasculitic/embolic phenomena; the presence of central venous access; a recent history of injected drug use; presence of a prosthetic valve; and positive blood cultures. The collective absence of these five criteria indicated a zero probability of TTE showing evidence of endocarditis.

CONCLUSIONS

The use of simple clinical criteria during the decision making process may avoid many unnecessary TTE examinations in hospital inpatients with a low probability of endocarditis.

Sensitivity of transthoracic versus transesophageal echocardiography for the detection of native valve vegetations in the modern era

BACKGROUND

Thirteen years ago, transthoracic echocardiography (TTE) was found to be less sensitive than transesophageal echocardiography (TEE) for native valve vegetations. Since then, harmonic imaging and other advances have improved TTE. How this affects the sensitivity of TTE is unknown.

METHODS

Fifty patients with echocardiography-diagnosed endocarditis had TTE and TEE examinations on high-end machines. These were matched for date of study with 50 patients who had TTE and TEE examinations that were negative for vegetations.

RESULTS

A total of 51 vegetations were seen on TEE. The sensitivity of TTE for vegetations was only 55% (aortic 50% [12/24]; mitral 62% [16/26]; tricuspid 0% [0/1]). Anatomic valvular abnormalities did not alter the sensitivity of TTE (P =.42 for mitral; P =.97 for aortic valves). However, larger vegetations were more likely to be found by TTE.

CONCLUSION

Despite advances in imaging during 12 years, TTE is still insensitive compared with TEE for the detection of native valve vegetations, and fails to demonstrate nearly half of them.

Endocarditis caused by Lactococcus cremoris

We describe a case of subacute endocarditis due to Lactococcus cremoris associated with consumption of unpasteurized milk. Treatment with amoxicillin-clavulanic acid and subsequently penicillin resulted in prompt sterilization of this patient's bloodstream and full recovery.

The changing clinical aspects of infective endocarditis: descriptive review of 90 episodes in a French teaching hospital and risk factors for death

OBJECTIVE

We wanted to describe the epidemiological aspects of infective endocarditis (IE) in a French hospital and identify the prognostic factors.

METHODS

We reviewed the clinical, echocardiographic and microbiological features, and the outcome of 89 patients (90 episodes, median age 60 years) with IE over 18 months. Logistic regression analysis was used to identify prognostic factors for death.

RESULTS

A native valve was involved in 68 cases (75.5%); in 7 of these the patient was an intravenous drug user. A prosthetic valve was involved in 22 cases (24.5%); 5 of these were of early onset. Diagnosis was definite in 87% of cases. Median time to diagnosis was 3 days. Twenty-five patients (28%) were immunocompromised. A portal of entry, usually cutaneous, was identified in 65% of cases. Sixty-two percent of patients had an underlying heart disorder, usually degenerative. The infection involved the left heart in more than 75% of cases. One or more vegetations were detected in 75% of cases. The median size of vegetation was 15 mm. Isolated agents were mainly staphylococci (n=40 (44%), including 12 coagulase-negative isolates), and streptococci (n=23 (25%), including 7 enterococci). In 11 cases (12%), cultures remained negative. Nineteen episodes were nosocomial and Staphylococcus aureus was implicated in 11 of them. Fifty percent of patients had at least one complication: heart failure (n=42), kidney failure (n=44), embolism (n=35), septic shock (n=19). Surgery was performed in 49 cases (54%) due to heart failure (n=19), cerebral embolism (n=12), and/or severe valve lesions (n=27). Eighteen patients died, 10 of whom were infected with S. aureus. Nosocomial IE (P=0.0008), heart failure (P=0.004) and prosthetic valve (P=0.01), but not S. aureus were independently associated with death.

CONCLUSIONS

S. aureus was the main microorganism isolated in our patients. However, it was not independently predictive of fatal outcome.

Volume quantification of intracardiac mass lesions by transesophageal three-dimensional echocardiography

As compared with two-dimensional (2-D) transesophageal echocardiography (TEE), 3-D echocardiography now permits more realistic visualization of cardiac anatomy and of intracardiac lesions. The aim of this study was to apply newer 3-D echocardiographic techniques to quantify volumes of intracardiac masses undergoing surgical resection seen during an intraoperative TEE. The calculated volumes were compared with actual in vitro measurements of surgically resected masses. A total of 14 patients (9 men; 5 women; age range between 21 and 77 years) with intracardiac mass lesions (4 tumors: 3 left atrial myxomas and 1 mitral valve fibroelastoma, and 10 vegetations: 5 aortic valve, 3 mitral valve, 1 tricuspid and 1 pulmonary valve) were studied. Using commercially available 3-D reconstruction software (TomTec v. 4.1), the volumes of intracardiac masses were estimated using both the average rotation (rotation around the long axis, AR) and disk summation (parallel short axis cuts, DS) methods. Volumes of these lesions were also measured in vitro by water submersion. They ranged from 0.20 mL to 24 mL (mean +/- SD = 8.07 +/- 9.21 mL). Both 3-D TEE AR and 3-D TEE DS calculated volumes correlated excellently with in vitro measured volumes (r = 1.00 and r = 0.98, respectively, p = < 0.0001). The correlation between 3-D TEE AR and 3-D TEE DS calculated volumes was also excellent (r = 0.98, p = < 0.0001). In conclusion, the volume assessments by 3-D TEE of intracardiac mass lesions correlated well with in vitro measured volumes of surgical specimens. This technique may prove to be valuable in further defining intracardiac pathology and is a further advancement toward the application of clinically useful 3-D echocardiography.

Role of echocardiography in the diagnosis and management of infective endocarditis

Infective endocarditis is a life-threatening disease with significant morbidity and mortality. Accurate and early diagnosis for initiation of effective treatment is essential in improving patient outcome. Echocardiography is currently the primary modality for the detection of vegetations and cardiac complications that result from endocarditis. Technological advances in echocardiography, particularly the development of transesophageal echocardiography (TEE), have revolutionized the diagnosis and management of infective endocarditis. With the enhanced resolution provided by TEE, vegetations and paravalvular complications can be reliably detected. Transthoracic and transesophageal echocardiography provides complementary information for patient management and follow-up, and is best used in conjunction with clinical data. By means of its high sensitivity and negative predictive value, TEE is essential in the evaluation of prosthetic valve endocarditis and the paravalvular complications of IE. All patients with suspected infective endocarditis should undergo transthoracic echocardiography, and most of these patients should also undergo TEE evaluation. The role of new technology such as harmonic and three-dimensional imaging is yet to be determined.

Transoesophageal echocardiography in selecting patients for anticoagulation after ischaemic stroke or transient ischaemic attack

OBJECTIVES

To investigate prospectively the role of transoesophageal echocardiography (TEE) in selecting patients for anticoagulation in an unselected stroke population.

METHODS

Transthoracic echocardiography (TTE) and TEE were done in all clinically suitable hospitalised patients (n = 457) with transient ischaemic attack or ischaemic stroke in the acute phase during a two year period in Turku University Hospital. 441 patients were successfully evaluated for cardiac sources of embolism using TEE within 31 days of the event.

RESULTS

A major risk factor for a cardiac source of embolism excluding atrial fibrillation, acute myocardial infarction, and prosthetic valve was detected in 10% of patients and a minor risk factor for a cardiac source of embolism in 46%. When a major risk factor of a cardiac source of embolism was detected using TTE or TEE and no contraindications were present, the patient was given anticoagulation drugs. If a minor risk factor for a cardiac source of embolism was detected, anticoagulation treatment was started after clinical assessment, if no contraindications were present. In 62 (14%) cases, the patient was given oral anticoagulation drugs or the necessity of ongoing anticoagulation treatment was confirmed on the basis of TEE. When these anticoagulation treated patients were evaluated using logistic regression analysis, they were found to have significantly more atrial fibrillation and histories of myocardial infarctions. Moreover, the patients were mainly men. When patients in sinus rhythm and without any history of cardiac disease were analysed, 8% of patients were found to have been given anticoagulation drugs on the basis of TEE data.

CONCLUSION

This study suggests that TEE should be used in patients with stroke even without any clinical evidence of cardiac disease when the patients are candidates for anticoagulation.

Infective endocarditis in intravenous drug abusers and HIV-1 infected patients

Infective endocarditis (IE) is one of the most severe complications of parenteral drug abuse. The incidence of IE in intravenous drug abusers (IVDAs) is 2% to 5% per year, being responsible for 5% to 20% of hospital admissions and 5% to 10% of the overall death rate. IVDAs often develop recurrent IE. The prevalence of HIV infection among IVDAs with IE ranges between 30% and 70% in urban areas in developed countries. The incidence of IE in IVDAs is currently decreasing in some geographical areas, probably due to changes in drug administration habits undertaken by addicts in order to avoid HIV transmission. Overall, Staphylococcus aureus is the most common etiological agent, being in most geographical areas sensitive to methicillin (MSSA). The remainder of cases is caused by streptocococci, enterococci, GNR, Candida spp, and other less common organisms. Polymicrobial infection occurs in 2% to 5% of cases. The tricuspid valve is the most frequently affected (60% to 70%), followed by the mitral and aortic valves (20% to 30%); pulmonic valve infection is rare (< 1%). More than one valve is infected in 5% to 10% of cases. HIV-positive IVDAs have a higher ratio of right-sided IE and S. aureus IE than HIV-negative IVDAs. Response to antibiotic therapy is similar among HIV-infected or non-HIV-infected IVDAs. Drug addicts with non-complicated MSSA right-sided IE can be treated successfully with an i.v. short-course regimen of nafcillin or cloxacillin for 2 weeks, with or without addition of an aminoglycoside during the first 3 to 7 days. Surgery in HIV-infected IVDAs with IE does not worsen the prognosis. The prognosis of right-sided endocarditis is generally good; overall mortality is less than 5%, and with surgery less than 2%. In contrast, the prognosis of left-sided IE is less favorable; mortality is 20% to 30%, and even with surgery is 15% to 25%. IE caused by GNB or fungi has the worst prognosis. Mortality between HIV-infected or non-HIV-infected IVDAs with IE is similar. However, among HIV-infected IVDAs, mortality is significantly higher in those who are most severely immunosuppressed, with CD4+ cell count < 200/microL or with AIDS criteria. Finally, IE in HIV-infected patients who are not drug abusers is rare.

Current best practices and guidelines. Assessment and management of complications in infective endocarditis

The most important complications of endocarditis are congestive heart failure, paravalvular abscess formation, and embolism, especially stroke. In addition, endocarditis may be complicated by septic arthritis, vertebral osteomyelitis, pericarditis, metastatic abscesses and an array of renal problems ranging from immune-complex glomerulonephritis to renal abscesses. Adverse reactions associated with medical treatment of endocarditis can also result in significant complications such as ototoxicity and nephrotoxicity, skin rashes, and serum sickness. This review focuses on the cardiac, embolic, neurologic and renal complications of endocarditis and discusses how these complications influence the clinical management of individual cases in daily practice.

Risk of embolization after institution of antibiotic therapy for infective endocarditis

OBJECTIVES

This study was designed to assess the risk of systemic embolization in patients with left-sided infective endocarditis, once adequate antibiotic treatment had been initiated, on the basis of prospective clinical follow-up.

BACKGROUND

As one of the complications of infective endocarditis, embolization has a great impact on prognosis. Prediction of an individual patient's risk of embolization is very difficult.

METHODS

We studied 217 episodes of left-sided endocarditis that were experienced among a cohort of 211 prospectively recruited patients. According to the Duke criteria, 91% of the episodes were definite infective endocarditis. Seventy-two episodes involved infections located on prosthetic valves. All patients were studied by transthoracic and transesophageal echocardiography. Clinical, echocardiographic and microbiologic data were entered in a data base. The mean follow-up interval was 151 days.

RESULTS

Twenty-eight episodes (12.9%; group I) of endocarditis had embolic events after the initiation of antibiotic therapy. The remaining 189 episodes did not embolize (group II). Most emboli (52%) affected the central nervous system, and 65% of the embolic events occurred during the first two weeks after initiation of antibiotic therapy. Previous embolism was associated with new embolism (relative risk [RR] 1.73, 95% confidence interval [CI] 1.02 to 2.93; p = 0.05). There was an increase in the risk of embolization with increasing vegetation size (RR 3.77, 95% CI 0.97 to 12.57; p = 0.07). Vegetation size had no impact on the risk of embolization in streptococcal endocarditis or aortic infection. By contrast, large (> or = 10 mm) vegetations had a higher incidence of embolism when the microorganism was staphylococcus (p = 0.04) and the mitral valve was infected (p = 0.03). The increase in vegetation size at follow-up showed a higher risk for embolization (RR 2.64, 95% CI 0.98 to 7.16; p = 0.02).

CONCLUSIONS

Embolism before antimicrobial therapy is a risk factor for new emboli. The risk of embolization seems to increase with increasing vegetation size, and this is particularly significant in mitral endocarditis and staphylococcal endocarditis. An increase in vegetation size, despite antimicrobial treatment, may predict later embolism.

Acute ischemic stroke patterns in infective and nonbacterial thrombotic endocarditis: a diffusion-weighted magnetic resonance imaging study

BACKGROUND AND PURPOSE

Although infective endocarditis (IE) and nonbacterial thrombotic endocarditis (NBTE) are associated with cardioembolic stroke, differences in the nature of these conditions may result in differences in associated stroke patterns. We compared patterns of acute and recurrent ischemic stroke in IE and NBTE, using diffusion-weighted MRI (DWI).

METHODS

Using ICD-9 diagnostic codes and medical record review, we identified 362 patients (387 episodes) with IE and 14 patients with NBTE. Thirty-five patients (with 27 episodes of IE, 9 NBTE) who underwent 36 initial and 29 follow-up DWI scans were selected for this study. DWI lesion size, number, and location were compared between groups and correlated with stroke syndromes and endocarditis features.

RESULTS

DWI was abnormal in all but 2 patients. Four acute stroke patterns were identified: (1) single lesion, (2) territorial infarction, (3) disseminated punctate lesions, and (4) numerous small (<10 mm) and medium (10 to 30 mm) or large (>30 mm) lesions in multiple territories. All patients with NBTE exhibited pattern 4, whereas those with IE exhibited patterns 1, 2, 3, and 4 (6, 2, 8 and 9 episodes, respectively). Seventy-five percent of patients with pattern 3 exhibited the clinical syndrome of embolic encephalopathy. Vegetation size, valve, and organisms had no correlation with stroke patterns.

CONCLUSION

DWI has utility in differentiating between IE and NBTE. Patients with NBTE uniformly have multiple, widely distributed, small and large strokes, whereas patients with IE exhibit a panoply of stroke patterns.

Functional tricuspid regurgitation secondary to aortic annular abscess: An unusual presentation of infective endocarditis

An unusual case of aortic annular abscess is presented, in which the patient presented with features of gross tricuspid regurgitation. There was no direct involvement of the tricuspid valve. Tricuspid regurgitation disappeared following surgical repair of the annular abscess. The present case also illustrates the utility of trans-oesophageal echocardiography in establishing the diagnosis and planning surgical intervention.

Comparison of clinical and echocardiographic characteristics of Streptococcus bovis endocarditis with that caused by other pathogens

The aim of our study was to compare the clinical, echographic, and prognostic features of Streptococcus bovis (S. bovis) endocarditis with those caused by other streptococci and pathogens in a large sample of patients with definite endocarditis by Duke criteria, using transesophageal echocardiography. Two hundred six patients (149 men, mean age 57 +/- 15 years) with a diagnosis of infective endocarditis formed the study population. All patients underwent multiplane transesophageal echocardiography and blood cultures. Cerebral, thoracoabdominal computed tomographic scan was performed in almost all patients (95%). All patients with S. bovis endocarditis underwent colonoscopy. Incidence of S. bovis endocarditis in our sample was 19%. Patients with S. bovis endocarditis were older than other groups. Multiple valve involvement, native valves, and large vegetations (>10 mm) were more frequent in patients with S. bovis. There was a significantly higher occurrence of embolism in the S. bovis group. Splenic embolism and multiple embolisms were significantly more frequent in patients with S. bovis. Gastrointestinal lesions, anemia, and spondylitis were observed more frequently with S. bovis endocarditis. In addition to the requirement for gastrointestinal examination for S. bovis endocarditis, our study underlines the need for systematic screening for vertebral and splenic localizations, and suggests the use of early surgery to prevent the high risk of embolism in these patients.

Patient selection criteria and management guidelines for outpatient parenteral antibiotic therapy for native valve infective endocarditis

Outpatient parenteral antibiotic therapy (OPAT) for infective endocarditis (IE) is being applied widely, despite the absence of controlled data that demonstrates that outcomes are equivalent to those with standard inpatient antibiotic therapy. We review existing OPAT guidelines, published data on the timing of complications from IE, and data on risk factors that can be used to predict complications. These data are used to propose more stringent criteria for patient selection and clinical management of OPAT for native valve IE. We recommend a conservative approach (inpatient or daily outpatient follow-up) during the critical phase (weeks 0-2 of treatment), when complications are most likely, and we recommend consideration of OPAT for the continuation phase (weeks 2-4 or 2-6 of treatment) when life-threatening complications are less likely.

The risk of stroke and death in patients with aortic and mitral valve endocarditis

BACKGROUND

Previous studies have generated inconsistent results when attempting to define predictors of stroke and death in patients with endocarditis. We sought to examine the relationship between vegetation 2-dimensional size and stroke in those with infective endocarditis (IE) and to identify differences between aortic valve (AV) and mitral valve (MV) IE with regard to clinical characteristics, echocardiographic findings, stroke, and death.

METHODS

We used the Duke Endocarditis Database to examine 145 episodes of definite IE involving the AV, n = 62, or MV, n = 83. A logistic regression model was developed to analyze important variables in predicting stroke, and a Cox proportional hazards model was used in predicting mortality.

RESULTS

The mitral valve was infected in 57% of the cases. Vegetations were more commonly detected in patients with MV IE (92.8% vs 66.1%, P =.001) and these MV vegetations were significantly larger (P <.05). Thirty-four of 145 episodes (23.4%) were complicated by stroke. MV IE was associated with a greater stroke rate, 32.5% versus 11.3% (P =.003). Strokes tended to occur early in the course of illness, particularly in MV IE. In the multivariable model, the independent predictors of stroke were MV IE (P =.04) and vegetation length (P =.03). Independent predictors of 1-year mortality were age (P =.02) and vegetation area (P =.048).

CONCLUSION

Stroke is more common in patients with MV IE. Vegetation 2-dimensional size and characteristics are important predictors of stroke and mortality. These findings may lead to predictive models that allow physicians to identify high-risk patients who need aggressive treatment strategies to prevent long-term morbidity and mortality.

Infective endocarditis in children--incidence, pattern, diagnosis and management in a developing country

BACKGROUND

In developing countries, patients with infective endocarditis are referred late, there is low yield of blood cultures and incidence of rheumatic heart disease is still high.

OBJECTIVE

Evaluate clinical pattern, assess diagnostic criteria in our settings and determine outcome.

SETTING

A tertiary referral center for paediatric and adult cardiology.

PATIENTS AND METHODS

All children with infective endocarditis admitted to a single center from April 1997 to March 2000 were analysed. The diagnosis was based on Duke's criteria, which proposed two major and six minor criteria. Minor criteria were expanded to include raised acute phase reactants and presence of newly diagnosed or increasing splenomegally. The patients were stratified as definite, possible and rejected cases.

RESULTS

Of 1402 hospital admissions, 45 patients fulfilled the diagnostic criteria for infective endocarditis giving an incidence of 32 per 1000 hospital admissions. The mean age was 7.9 +/- 4 years (4 months to 16 years) with only two patients under 1 year of age. Rheumatic heart disease was the underlying lesion in 24 patients (53%) while congenital heart lesions occurred in 20 patients (45%). Previous antibiotic treatment was given in 26 patients (58%) definitely. Blood cultures were positive in 21 patients (47%); Streptococcus Viridans being the most common organism, while vegetations on echocardiography were present in 32 patients (71%). Surgery was undertaken in four patients and five patients left against medical advise. Of 10 patients with aortic valve involvement, there were three deaths (30%) and overall mortality was 13% (six patients).

CONCLUSIONS

The incidence of infective endocarditis is 32 per 1000 (3.2%) hospital admissions in a tertiary paediatric cardiology referral center. Rheumatic heart disease is still the most common underlying heart lesion. Blood cultures are positive in less than 50% of cases and echocardiography in expert hands is a more sensitive tool in our set up. Mortality is still high and aortic valve involvement in particular, carried poor prognosis.

Echocardiography predicts embolic events in infective endocarditis

OBJECTIVES

The aim of our study was to assess the value of transesophageal echocardiography (TEE) in predicting embolic events (EEs) in a large group of patients with definite endocarditis according to the Duke criteria, including silent embolism.

BACKGROUND

The value of echocardiography in predicting embolism in patients with endocarditis remains controversial. Some studies reported an increased risk of embolism in patients with large and mobile vegetations, whereas other studies failed to demonstrate such a relationship.

METHODS

Multiplane transesophageal echocardiograms of 178 consecutive patients with definite infective endocarditis (IE) were analyzed. The incidence of embolism was compared with the echocardiographic characteristics (localization, size and mobility) of the vegetations. To detect silent embolism, cerebral and thoraco-abdominal scans were performed in 95% of patients.

RESULTS

Among 178 patients, 66 (37%) had one or more EEs. There was no difference between patients with and without embolism in terms of age, gender and left valve involved. On univariate analysis, Staphylococcus infection, right-side valve endocarditis and vegetation length and mobility were significantly related to EEs. A significant higher incidence of embolism was present in patients with vegetation length >10 mm (60%, p < 0.001) and in patients with mobile vegetations (62%, p < 0.001). Embolism was particularly frequent among 30 patients with both severely mobile and large vegetations (> 15 mm) (83%, p < 0.001). On multivariate analysis, the only predictors of embolism were vegetation length (p = 0.03) and mobility (p = 0.01).

CONCLUSIONS

Our study shows that the presence of vegetations on TEE is predictive of embolism and that the morphologic characteristics of vegetations are helpful in predicting EEs in both mitral and aortic valve IE. It also suggests that early operation may be recommended in patients with vegetations > 15 mm and high mobility, irrespective of the degree of valve destruction, heart failure and response to antibiotic therapy.