Incidence of bacteremia in transesophageal echocardiography: a prospective study of 140 consecutive patients

Cost-Effectiveness of Echocardiography to Identify Intracardiac Thrombus among Patients with First Stroke or Transient Ischemic Attack

Background and Purpose . Echocardiography to select stroke patients for targeted treatments, such as anticoagulation (AC), to reduce recurrent stroke risk is controversial. The authors' objective was to evaluate the cost-effectiveness of imaging strategies that use transthoracic (TTE) and transesophageal (TEE) echocardiography for identifying intracardiac thrombus in new stroke patients. Methods . Model-based cost-effectiveness analysis of 7 echocardiographic imaging strategies and 2 nontesting strategies with model parameters based on systematic evidence review related to effectiveness of echocardiography in newly diagnosed ischemic stroke patients (white males aged 65 years in base case). Primary outcome was cost per quality-adjusted life year (QALY). Results . All strategies containing TTE were dominated by others and were eliminated from the analysis. Assuming that AC reduces recurrent stroke risk from intracardiac thrombus by 43% over 1 year, TEE generated a cost per QALY of $137,000 (relative to standard treatment) among patients with 5% thrombus prevalence. Cost per QALY dropped to $50,000 in patients with at least 15% intracardiac thrombus prevalence, or, if an 86% relative risk reduction with AC is assumed, in patients with thrombus prevalence of at least 6%. Probabilistic analyses indicate considerable uncertainty around the cost-effectiveness of echocardiography across a wide range of intracardiac thrombus prevalence (pretest probability). Conclusions . Current evidence on cost-effectiveness is insufficient to justify widespread use of echocardiography in stroke patients. Additional research on recurrent stroke risk in patients with intracardiac thrombus and on the efficacy of AC in reducing that risk may contribute to a better understanding of the circumstances under which echocardiography will be cost-effective. Key words: cost-effectiveness; decision analysis; stroke; transesophageal echocardiography; transthoracic echocardiography; diagnostic imaging. (Med Decis Making 2007;27:161—177)

The safety of transesophageal echocardiography in patients undergoing orthotopic liver transplantation

OBJECTIVE

To evaluate the safety of transesophageal echocardiography for the evaluation and intraoperative monitoring of patients during orthotopic liver transplantation.

DESIGN

Retrospective observational study.

SETTING

Tertiary care, university teaching hospital.

PARTICIPANTS

Patients (n = 116) who underwent intraoperative transesophageal echocardiography during liver transplantation.

INTERVENTIONS

Intraoperative transesophageal echocardiography during liver transplantation.

MEASUREMENTS AND MAIN RESULTS

The authors evaluated the safety of intraoperative transesophageal echocardiography in patients undergoing liver transplantation through a retrospective chart review. Complications associated with transesophageal echocardiography use were divided into minor and major complications. Out of 116 patients who underwent intraoperative transesophageal echocardiography, there was one minor and one major complication. The major complication rate was 0.86% (1/116) and the overall complication rate was 1.7% (2/116). There was no statistically significant correlation between pre-transplant sclerotherapy for treatment of varices and intraoperative transesophageal echocardiography-related gastrointestinal bleeding. Although the reported complication rate is higher than what has been quoted in the cardiac literature, intraoperative transesophageal echocardiography during liver transplantation has a low complication rate.

CONCLUSIONS

Intraoperative transesophageal echocardiography is a relatively safe method of monitoring cardiac performance in liver transplant patients.

Is antibiotic prophylaxis ever necessary before transoesophageal echocardiography?

Evidence strongly suggests that antibiotic prophylaxis should not be used routinely for transoesophageal echocardiography for any indication.

Prophylactic use of vancomycin in adult cardiology and cardiac surgery

The recent appearance of Staphylococcus aureus and Staphylococcus epidermidis strains that have reduced susceptibility to vancomycin, and the spread of vancomycin-resistant enterococci, raise the specter of endovascular infections that will be difficult or impossible to cure with available drugs. We review issues concerning the prophylactic use of vancomycin in adult cardiology and cardiac surgery with special attention to dosing and indications. There is no indication for the routine use of prophylactic vancomycin in pacemaker implantations, cardiac catheterization, and transesophageal echocardiography. In institutions with a high incidence of methicillin-resistant S. aureus and S. epidermidis, vancomycin may be used for antibiotic prophylaxis in place of cephalosporins for pacemaker or defibrillator implantation. The strongest evidence in support of the prophylactic use of vancomycin is during cardiac surgeries, particularly valvular surgeries in institutions with a high prevalence of methicillin-resistant S. aureus and S. epidermidis. When vancomycin is used prior to open heart surgery, the dose should be 15 mg/kg rather than the standard 1 g dose that is often recommended in the literature and used by 85% of institutional pharmacists who responded to our survey. Cardiologists and cardiac surgeons should assume leadership roles in promoting its responsible use.

Biplane transesophageal echocardiography in the normal cat

Eight healthy, adult cats were examined with biplane transesophageal echocardiography (TEE). Cats were sedated with a combination of diazepam and propofol and were examined using a 5 mm x 80 cm pediatric biplane TEE probe. Consistent images were obtained at three imaging depths within the esophagus. The caudal position provided satisfactory short-axis images of the left ventricle and heart base. The middle position provided the best long-axis views of the left atrium, left ventricle, and aorta and allowed Doppler examination of transmitral left ventricular inflow. The cranial position provided satisfactory imaging of the aorta and pulmonary artery and allowed Doppler examination of right ventricular and left ventricular outflow. Biplane TEE provides an additional method of imaging the feline heart which is complimentary to other imaging techniques and the images obtained were similar to those reported for dogs. Although TEE offers a slight advantage over transthorcic imaging for Doppler examination, the quality of the images of heart base structures was not as consistently superior to transthoracic images in cats as reported in dogs.

Intraoperative transesophageal echocardiography during liver transplantation

OBJECTIVE

To investigate the safety, value, and impact of transesophageal echocardiography during liver transplantation.

DESIGN

Retrospective.

SETTING

University teaching hospital.

PARTICIPANTS AND INTERVENTIONS

The medical records of 346 patients and the videotapes of 100 intraoperative transesophageal echocardiography examinations were reviewed.

MEASUREMENTS AND MAIN RESULTS

Transesophageal echocardiography was indicated for intraoperative monitoring in 62 patients, 41 of whom had pertinent findings, and for diagnostic purposes in 38 patients, 14 of whom had the expected diagnosis verified. Thirty-one patients had no intraoperative findings. Information that would not have been detected intraoperatively by other means included intracardiac defects, the potential for transpulmonary air passage, valvular regurgitation, the presence or absence of ventricular dysfunction, and embolization occurring at allograft reperfusion. Unanticipated findings during the initial transesophageal echocardiography examination as well as evaluation of intraoperative events resulted in a major impact on patient management in 11% of patients. Preoperatively, 64 patients had a prothrombin time greater than 14 seconds; 56 had a platelet count less than 100,000/mm3; and 23 had esophageal varices, 7 of whom had not had variceal sclerotherapy. Two patients had a complication possibly caused by transesophageal echocardiography (sinus bradycardia and upper gastrointestinal bleeding). No patient experienced documented variceal hemorrhage, esophageal or gastric perforation, and/or oropharyngeal trauma.

CONCLUSIONS

It appears that transesophageal echocardiography can be performed safely in patients undergoing liver transplantation, is efficacious in rapidly disclosing new information and monitoring during periods of hemodynamic instability, and may have a significant impact on intraoperative patient management during liver transplantation.

Antibiotic Prophylaxis for Endocarditis Prevention During Transesophageal Echocardiography: Controversy, Consideration, and What Really Happens

A survey was conducted in order to gain a better understanding of actual practice policies followed by academically affiliated institutions regarding the use of prophylactic antibiotics during transesophageal echocardiography. Results revealed that 10 of the 20 centers routinely used intravenous antibiotic prophylaxis for high risk transesophageal echocardiography. However, 5 of the 20 centers did not use any prophylactic antibiotics routinely, and the remaining 5 centers used primarily oral prophylactic regimens. In addition, the type of patient that was considered high risk for which antibiotic prophylaxis was used differed among institutions. Practice guidelines in 4 of the 20 institutions have changed in the last 5 years. These findings demonstrate a wide variation in the actual practice policies of different institutions, probably reflecting, in part, the lack of convincing evidence that prophylactic antibiotics benefit this subgroup of patients. (ECHOCARDIOGRAPHY, Volume 13, September 1996)

Risks for and prevention of infective endocarditis

It is accepted medical practice to prevent bacterial endocarditis in patients with susceptible congenital or acquired cardiac malformations who are likely to experience predictable procedure-related bacteremia. Patients in general, those with congenital heart disease specifically, are insufficiently aware of the need for such prophylaxis. It is responsibility of the physician to determine which patients are susceptible to endocarditis and the need for endocarditis prophylaxis for each patient for any given instance and to educate the patient as to this need. The American Heart Association provides wallet-sized cards that may be given to each patient. Those patients not previously known to have heart disease are, of course, not eligible for chemoprophylaxis. Because these represent many of the patients with endocarditis each year, it can be argued that only a minority of patients have preventable cases. Regarding the clinical application of anti-infective endocarditis prophylaxis, the American Heart Association gives this perspective: This statement represents recommended guidelines to supplement practitioners in the exercise of their clinical judgement and is not intended as a standard of care for all cases.... Because no adequate, controlled clinical trials of antibiotic regimens for the prevention of bacteria endocarditis in humans have been done, recommendations are based on vitro studies, clinical experience, data from experimental animal models, and assessment of both the bacteria most likely to produce bacteremia from a given site and those most likely to result in endocarditis. Bacterial endocarditis is one of the few infectious disease that almost always result in death unless treated. The dramatic nature of the morbidity and mortality of infective endocarditis in those so afflicted makes the prevention of even a few cases worth the effort.

Role of transthoracic and transesophageal echocardiography in diagnosis and management of infective endocarditis

Echocardiography has become a mainstay in the diagnosis of endocarditis. Vegetations were first visualized noninvasively beginning with M-mode echocardiography in the mid-1970s. The evolution of echocardiography, to include first two-dimensional imaging and then Doppler imaging in the 1980s, established echocardiography as the noninvasive test of choice to evaluate for the presence of vegetations as well as for their sequelae. Most recently, the addition of transesophageal echocardiography has expanded the role and yield of echocardiography in diagnosing endocarditis as well as in guiding management.

Critical appraisal of transesophageal echocardiography: limitations and pitfalls

As with any imaging technology, there are limitations and pitfalls to TEE. The limitations and pitfalls of TEE can be minimized best by experience. Initial training should not be circumvented, and maintenance of competency should be monitored strictly. Physicians with less than level II echocardiography training should work in close collaboration with an active echocardiography laboratory and have an appropriate review of current examinations. Both individual and laboratory standards for maintenance of competency should be established. Because of the new presentation of cardiac and extracardiac anatomy, unfamiliar but normal anatomy initially may be confused as abnormal. Additionally, certain structures are viewed in a manner that may mimic pathologic conditions. Because of the superior resolution offered by TEE, phenomena such as spontaneous contrast and ghosting are observed much more commonly than they are with transthoracic imaging. Highly detailed anatomic structures, such as atrial muscle bundles, sutures, and adipose tissue, are to be recognized and differentiated from thrombi, vegetation, and masses. Although TEE has been a dramatic step forward in diagnostic imaging, there is a potential for serious misinterpretation. This article discusses most of these potential problems; however, there always will be unique situations in which the findings must be addressed consistently and differentiated as normal, artifact, new observation, or misinterpretation.

Frequency of bacteremia associated with transesophageal echocardiography in intensive care unit patients: a prospective study of 139 patients

OBJECTIVE

To determine the occurrence rate of bacteremia associated with transesophageal echocardiography in intensive care unit (ICU) patients.

DESIGN

A prospective study of 139 patients undergoing transesophageal echocardiography.

SETTING

The medical ICU of a tertiary referral teaching hospital.

PATIENTS

One hundred thirty-nine ICU patients (mean age 58 yrs) who underwent transesophageal echocardiography.

INTERVENTIONS

Blood samples were systematically drawn for aerobic and anaerobic culture at the following times: before (blood culture 1), at the end of (blood culture 2), and 30 mins after (blood culture 3) transesophageal echocardiography examinations.

MEASUREMENTS AND MAIN RESULTS

The mean duration of transesophageal echocardiography was 35 mins (range 7 to 120). One hundred thirty-four patients received mechanical ventilation; 125 patients had a nasogastric tube. Fifty-one patients had one or more underlying conditions that usually justify antimicrobial prophylaxis of bacterial endocarditis before high-risk procedures. Fifty-six patients did not receive any antibiotic treatment at the time of transesophageal echocardiography. In 114 patients, the three blood cultures were negative. In six patients, transesophageal echocardiography was performed during a preexisting bacteremia. A contamination (only one positive blood culture of the three sampling times) with coagulase-negative staphylococci occurred in four patients at blood culture 1, five patients at blood culture 2, and six patients at blood culture 3. Contamination with Corynebacterium species occurred in two patients at blood culture 2. In one patient receiving cefotaxime and netilmicin, blood culture 1 was sterile and blood cultures 2 and 3 yielded coagulase-negative staphylococci. In one patient receiving no antibiotic treatment, blood culture 1 was sterile and blood cultures 2 and 3 yielded Enterococcus faecalis. None of these two patients received a specific antibiotic treatment or developed any secondary septic focus.

CONCLUSIONS

The overall frequency of bacteremia induced by transesophageal echocardiography in ICU patients was 1.4% (two of 139 patients) (95% confidence interval 0.2% to 5.1%). The frequency did not differ whether patients received antibiotics before transesophageal echocardiography (one [1.2%] of 83 patients) or not (one [1.8%] of 56 patients) (p = .96). Therefore, routine antimicrobial prophylaxis does not appear justified before transesophageal echocardiography in ICU patients.

Hypoxaemia during transoesophageal echocardiography

OBJECTIVES

To establish the incidence and severity of arterial oxygen desaturation during transoesophageal echocardiography performed under light intravenous sedation; to determine which patients are at greatest risk; and to assess the effects of supplementary oxygen treatment.

DESIGN

Prospective study of 150 patients referred for transoesophageal echocardiography.

SETTING

Echocardiography laboratory in a tertiary cardiothoracic referral centre.

MAIN OUTCOME MEASURE

Transcutaneous arterial oxygen saturation.

RESULTS

During transoesophageal echocardiography mean (SD) arterial oxygen saturation (SaO2) fell in 144 of 150 patients (96%) from 95.4%(2.6%) to 90.7%(6.3%) (p < 0.001). Significant hypoxaemia, defined as SaO2 < 90%, was found in 27 of 150 patients (18%); in this group SaO2 fell from 92.9%(3.5%) to 81.8%(9.6%) (p < 0.001), but rose rapidly on oxygen to 95.5%(2.4%) (p < 0.001). Two patients became profoundly hypoxaemic with SaO2 values of 35% and 74%. The principal risk factors for hypoxaemia during transoesophageal echocardiography were mitral valve disease, severe mitral regurgitation, and New York Heart Association symptomatic class III or IV.

CONCLUSIONS

Transcutaneous oximetry and supplementary oxygen should be available routinely during transoesophageal echocardiography.

Application of transthoracic and transesophageal echocardiography in the diagnosis and management of infective endocarditis

Infective endocarditis continues to be a cause of significant cardiac morbidity and mortality. To improve the prognosis of patients with this disorder, early diagnosis is crucial but difficult to establish on the basis of clinical parameters alone. Echocardiography, both transthoracic and transesophageal techniques, has a major role in the detection of vegetations that are the hallmark of endocarditis. Valvular and perivalvular complications can also be well assessed by echocardiography. With the improved resolution provided by recent technologic advances in echocardiography, vegetations can be reliably detected in most patients with endocarditis. We propose that present diagnostic criteria for endocarditis be revised to include echocardiographic findings as a major parameter in the diagnosis. Finally, a diagnostic approach incorporating transthoracic and transesophageal echocardiography in these patients will be discussed taking into consideration the different degrees of clinical suspicion for the existence of the disease.

[Antibiotic prophylaxis in heart surgery]

Cardiac surgery enters mainly into the class I of Altemeier ("clean surgery"). However, many factors may explain an intraoperative contamination: surgery of long duration, extra-corporeal circulation, aspiration of blood and air, immunodepression...). In fact, the infectious risk decreases from about 25% with placebo to 5% with prophylactic antibiotics. The staphylococcal infections are the most frequent (mediastinitis, endocarditis, parietal infections...). Cephalosporins, particularly of second-generation type (cefamandole, cefuroxime), perform better than antistaphylococcal penicillins. The combination with an amino-side may be used when Gram negative bacilli infection prevalence is high. Vancomycin is efficient but hypotension and renal impairment have been reported. Therefore, vancomycin is used in patients allergic to cephalosporins, when a high prevalence of methicillin-resistant Staphylococcus or enterococci infections is reported, or when the patient has recently received broad-spectrum antimicrobial therapy. The antibiotic doses must take into account the haemodilution due to extracorporeal circulation and the necessity to obtain sufficient serum concentrations throughout surgery. A prophylaxis of more than 48 hours is not associated with an improved outcome. In cardiac transplantation a prophylaxis is essential, but is still questioned during the insertion of pace-markers. In any case, the antibiotic prophylaxis must take into account the bacterial prevalence of each institution.

Routine use of transesophageal echocardiography and color flow imaging in the evaluation and treatment of children with congenital heart disease

We reviewed our experience with transesophageal echocardiography (TEE) and color flow imaging in 157 consecutive patients with known or suspected heart disease to ascertain the impact of this technology on patient care. TEE was performed for diagnostic purposes (22/157), during interventional cardiac catheterizations (13/157), and during operative procedures (122/157). Diagnostic studies were performed after transthoracic echocardiography (TTE) in 21 of 22 patients. TEE was performed because TTE was inconclusive (15/21) or failed to provide sufficient detail of an abnormality (6/21). TEE detected an abnormality in 6 of 15 inconclusive TTEs. TEE was helpful during interventional cardiac catheterizations, particularly during umbrella closure of septal defects and in patients with complex venous and atrial anatomy undergoing transseptal puncture. TEE studies performed before cardiac operations significantly changed the diagnosis in only 5 of 122 (4%) patients, but the information changed the surgical approach in 4 of 5 of these patients. Postoperative TEE assessment more frequently changed care and resulted in further surgical management in 9 of 122 (7%) or a change in medical management in 6 of 122 (5%) patients. TEE was discontinued because of complications before studies were completed in only 4 of 157 (3%) patients. TEE and color flow imaging is a useful adjunct to care of children with known or suspected congenital heart disease.

Risk of endocarditis in transesophageal echocardiography

The risk of endocarditis associated with transesophageal echocardiography was studied in 101 patients. To evaluate possible bacteremia, blood cultures were performed on samples from consecutive patients who did not have clinical or laboratory evidence of infection. The broth blood culture Signal system was used in all patients, and additionally, the lysis-centrifugation technique was performed in a subgroup of 40 patients to further ameliorate recovery of rapidly phagocytosed germs. Comprehensive criteria for differentiation between true bacteremia and possible contamination were provided by means of simultaneous blood sampling from two separate venipuncture sites and skin specimens from the venipuncture area. Oropharyngeal specimens were cultured for evaluation of possible association of oropharyngeal flora with positive blood culture findings. They revealed facultative pathogenic isolates, as well as physiologic residental flora, in 15 patients. All blood isolates that were recovered simultaneously 6 minutes after the procedure were found to be sterile. Correspondingly, clinical follow-up for 2 weeks was uneventful with regard to episodes of infection. These results indicate that the risk of bacteremia associated with transesophageal echocardiography is extremely low. Thus endocarditis prophylaxis is not required for this procedure.

Implication of negative results on a monoplane transesophageal echocardiographic study in patients with suspected infective endocarditis

OBJECTIVES

This study was conducted to determine the implications of negative findings on a transesophageal echocardiographic study in which neither a vegetation nor an abscess is identified in patients with clinically suspected infective endocarditis.

BACKGROUND

Echocardiography is the procedure of choice for evaluating suspected infective endocarditis in patients. Transesophageal echocardiography has been shown to be superior to transthoracic imaging. Although the importance of positive results or a diagnostic study is known, the significance of negative findings on a transesophageal study is not clear.

METHODS

All transesophageal echocardiographic studies performed over a 2-year period for suspected infective endocarditis were reviewed and the clinical course of patients with an initially negative study result was assessed to determine their final diagnosis.

RESULTS

Of the 105 patients identified, 65 had a negative transesophageal study result. In the majority of this group (56 of 65), an alternate diagnosis was made or there was no infective endocarditis on follow-up examination, or both. Of the remaining nine patients, four were treated for endocarditis without a definite diagnosis and five had infective endocarditis proved by either repeat transesophageal study (n = 3), pathologic findings (n = 1) or a diagnostic clinical course (n = 1). Gram-positive bacteremia and the presence of a prosthetic valve in the aortic position tended to be more common in the latter group.

CONCLUSIONS

A negative transesophageal study result reduces the likelihood that endocarditis is present. Repeat examination, however, should be considered in high risk patients, such as those with prosthetic valves or unexplained bacteremia, to avoid a missed diagnosis.

Prospective study of blood culture during transesophageal echocardiography

To ascertain the incidence and significance of bacteremia associated with transesophageal echocardiography (TEE), 132 consecutive patients (aged 17 to 73 years) free of apparent infection who were undergoing 135 transesophageal echocardiographic procedures from October 1990 to August 1991, were prospectively studied. For each procedure, two sets of blood cultures were obtained for culture 30 to 60 minutes before TEE, immediately after, and 180 to 240 minutes after the procedure. For each blood culture, 10 ml of venous blood was evenly inoculated into aerobic and anaerobic culture bottles and inoculated for 7 days using a radiometric system. A throat swab was obtained immediately before each procedure. Three of 270 preprocedure blood cultures were positive for Bacillus cereus, Staphylococcus simulans, and Peptostreptococcus species, respectively. No blood culture was positive in the immediate postprocedure period. Two of 270 late blood samples grew Staphylococcus epidermidis in the same patient. Nevertheless, the microorganisms isolated from blood cultures were different from those isolated from the throat swab. No patients had fever or evidence of infective endocarditis after TEE during the follow-up period. It is concluded that the incidence of TEE-related bacteremia is extremely low, and a general recommendation for antibiotic prophylaxis during TEE is not warranted.

The role of transesophageal echocardiography in critical care: UCSF experience

The applications of transesophageal echocardiography (TEE) now encompass the arena of critical care. We reviewed the indications, findings, and outcome of TEE in the critical care setting in a tertiary care hospital and report our experience. Eighty-three transesophageal echocardiograms were performed in 69 critically ill patients for the following indications: endocarditis (43%), embolic source (13%), hypotension (10%), mitral regurgitation (10%), left ventricular function (6%), aortic dissection (4%), prosthetic valve dissection (4%), and other (10%). Findings were unexpected in 21 of 83 studies and led to a change in management in 17%. On the basis of the results of TEE, 22% of patients had further evaluation by a more invasive technique, and 19% of patients had surgical intervention without further study. No significant complications attributable to TEE were noted. We conclude that TEE is a safe and useful diagnostic technique with fairly broad applications in the critical care setting.

Critical appraisal of transesophageal echocardiography: limitations, pitfalls, and complications

Because transesophageal echocardiography is invasive, it has the potential for serious complications. Limitations occur because of the restricted transducer mobility within transducers for special situations. Pitfalls (potential erroneous diagnoses resulting from misinterpretation of normal and abnormal anatomy) are prevalent with this new technology. This report critically reviews transesophageal echocardiography and discusses and illustrates commonly encountered limitations, pitfalls, and complications.