Transesophageal Ultrasonography Research Articles

Intraoperative effectiveness of crystalloid and colloid volume substitution in patients undergoing elective major urological surgery by maintenance of the cardiac index within normal range

We compared intraoperative volume effectiveness of crystalloid and colloid substitution aimed to maintain the cardiac index (CI) within the normal range measured by transesophageal Doppler ultrasonography (TED) [1]. We also evaluated the frequency of postoperative complications, length of in-hospital stay and postoperative in-hospital mortality.

Transbronchial and Transesophageal Fine-Needle Aspiration Using an Ultrasound Bronchoscope in Mediastinal Staging of Potentially Operable Lung Cancer

We performed this study to evaluate the role of transesophageal endoscopic ultrasound with bronchoscope-guided fine-needle aspiration (EUS-B-FNA) following endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in the mediastinal staging of lung cancer. In this prospective study, we applied transbronchial and transesophageal ultrasonography using an ultrasound bronchoscope on patients with confirmed or strongly suspected potentially operable non-small cell lung cancer. Following EBUS-TBNA, EUS-B-FNA was used for mediastinal nodes that were inaccessible or difficult to access by EBUS-TBNA. The accessibility by EBUS-TBNA and EUS-B-FNA to mediastinal nodal stations having at least one node ≥ 5 mm was also checked. In 150 patients, we performed EBUS-TBNA and EUS-B-FNA on 299 and 64 mediastinal nodal stations, respectively. Among 143 evaluable patients, EBUS-TBNA diagnosed mediastinal metastasis in 38 patients. EUS-B-FNA identified mediastinal metastasis in three additional patients. Surgery diagnosed mediastinal metastasis in four more patients. The sensitivity, negative predictive value, and diagnostic accuracy of EBUS-TBNA in the detection of mediastinal metastasis were 84.4%, 93.3%, and 95.1%, respectively. These values for the combined approach of EBUS-TBNA and EUS-B-FNA increased to 91.1%, 96.1%, and 97.2%, respectively, although the differences were not statistically significant (P = .332, P = .379, and P = .360, respectively). Among 473 mediastinal nodal stations having at least one node ≥ 5 mm that were evaluated, the proportion of accessible mediastinal nodal stations by EBUS-TBNA was 78.6%, and the proportion increased to 84.8% by combining EUS-B-FNA with EBUS-TBNA (P = .015). Following EBUS-TBNA in the mediastinal staging of potentially operable lung cancer, the accessibility to mediastinal nodal stations increased by adding EUS-B-FNA and an additional diagnostic gain might be obtained by EUS-B-FNA. clinicaltrials.gov, NCT00741247.

Ultrasound and the risk of nosocomial cross infection

. Non-critical probes arethose that come into contact with intact skin, as occursduring abdominal, breast and small-parts examinations.Semi-critical probes come into contact with a mucosalmembrane, as occurs during transesophageal, transvagi-nal and transrectal ultrasonography, or diseased/breachedskin. Critical probes come into contact with blood and/orother body cavity fluids or internal tissues, as occursduring intraoperative ultrasonography.Non-critical transducers require low-level disinfection.Removal of the applied ultrasound gel and subsequentcleaning of the transducer with a disinfectant wipe orspray after each examination is considered adequate

Acute Haemophilus parainfluenzae endocarditis: a case report

IntroductionNumerous pathogens can cause infective endocarditis, including Haemophilus parainfluenzae. H. parainfluenzae is part of the H. aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae group that may cause about 3% of the total endocarditis cases, and is characterized by a subacute course and large vegetations.Case presentationAcute H. parainfluenzae endocarditis developed in a 54-year-old woman, with no underlying predisposing factors. The patient presented with fever of 3 days duration and a severe headache. Magnetic resonance imaging of the brain revealed multiple cerebral emboli with hemorrhagic foci. Upon suspicion of endocarditis, cardiac transesophageal ultrasonography was performed and revealed massive vegetations. The patient underwent emergency mitral valve replacement, and was further treated with ceftriaxone. Blood cultures grew H. parainfluenzae only after valve replacement, and a 6-week course of ceftriaxone was prescribed.ConclusionWe underline the typical presentation of large vegetations in H. parainfluenzae endocarditis, which are associated with embolic phenomena and resulting severity. Although the majority of the few cases reported in the literature are subacute in progress, our case further underlines the possibility that H. parainfluenzae endocarditis may develop rapidly. Thus, awareness of the imaging characteristics of the pathogen may enhance early appropriate diagnosis and therapeutic response.

Immediate endovascular repair for acute traumatic injuries of the thoracic aorta: A multicenter analysis of 28 cases

Endovascular repair of injured thoracic aorta offers a new minimal invasive therapeutic option that could be beneficial in the urgent management of polytrauma patients. The aim of this study was to assess our multicenter experience of immediate endovascular repair for acute traumatic injuries of the thoracic aorta. Between April 2002 and October 2007, all patients treated for an acute traumatic injury of the thoracic aorta, in a less than 12-hour delay, by endovascular repair, were reviewed retrospectively in three Parisian trauma centers. Collected data included age, sex, associated comorbidities, and traumatic lesions to determine the Traumatic Injury Severity Score (TRISS), the type of aortic lesion assessed by computed tomography (CT)-scan and transesophageal ultrasonography, technical aspects of endovascular repair, length of hospital stay, and postoperative mortality. Patients were regularly followed by clinical examination, chest radiographs, and thoracic CT-scan. Twenty-eight patients (20 males, mean age 45 +/- 18.8 years) were treated in a median delay of 5 hours (range 2 to 10 hours) after initial trauma. They all experienced severe traumatic injuries with a mean predictive mortality of 55.6% +/- 33.1% according to TRISS. Aortic lesions were associated with aortic parietal hematoma (71%), hemomediastinum (86%), and hemothorax (68%). All endovascular procedures were technically successful through femoral (n = 24) or iliac access (n = 4), in a mean operating time of 94 +/- 35.8 minutes. Proximal sealing of the endografts required the coverage of the origin of the left subclavian artery in 13 cases and of the left common carotid in one case. The median of hospital stay was 27 days (range 9 to 127 days), with an overall hospital mortality of 17.9% (n = 5). All deaths were unrelated to the aortic rupture or the stent placement, and no intervention-related morbidity or mortality was recorded during a median follow-up of 24 months (range 5 to 73 months). Endovascular stent grafting allows an immediate efficient repair for acute traumatic injuries of the thoracic aorta. This early management is, however, associated with a high in-hospital mortality, related to the severe concomitant injuries of such unselected multitrauma patients.

Evaluation of transesophageal echo-Doppler ultrasonography for the measurement of aortic blood flow in anesthetized cats

To evaluate the use of a transesophageal echo-Doppler ultrasonography (TED) technique for measurement of aortic blood flow (ABF) in relation to cardiac output (CO) measured by use of a thermodilution technique in anesthetized cats. 6 adult cats (mean +/- SD body weight, 5 +/- 0.7 kg). Anesthesia was induced and maintained in cats by administration of isoflurane. A thermodilution catheter was placed in a pulmonary artery. The TED probe was positioned in the esophagus in the region where the aorta and esophagus are almost parallel. Five baseline values for ABF and CO were concurrently recorded. Cats were randomly assigned to a high or low CO state (increase or decrease in CO by at least 25% from baseline, respectively). Baseline conditions were restored, and the other CO state was induced, after which baseline conditions were again restored. For each CO state, ABF and CO were measured 5 times at 5-minute intervals. Correlation and agreement between the techniques were determined by use of the Pearson product-moment correlation and Bland-Altman method. CO ranged from 0.16 to 0.75 L/min and ABF from 0.05 to 0.48 L/min. Overall data analysis revealed a high correlation (r = 0.884) between techniques but poor agreement (limits of agreement, -0.277 to 0.028 L/min). During the low CO state, correlation between techniques was low (r = 0.413). TED did not accurately measure CO. However, it allowed evaluation of CO patterns and may be useful clinically in anesthetized cats.

Transurethral Resection Syndrome Detected and Managed Using Transesophageal Doppler

Transurethral resection syndrome during transurethral resection of the prostate (TURP) results from excessive absorption of electrolyte-free irrigation fluids causing acute hypervolemia and hyponatremia. Neuraxial anesthesia is often recommended for TURP procedures because early signs of neurological deterioration can be detected. However, in patients requiring general anesthesia, other continuous and noninvasive measures are needed. Acute intravascular hypervolemia should be reflected by changes in hemodynamic values. Transesophageal Doppler ultrasonography of the aorta allows determination of stroke volume and other advanced hemodynamic variables related to intravascular volume status. We describe the first case of intraoperative detection of a TURP syndrome by noninvasive Doppler monitoring of hemodynamic variables during TURP.

Transösophagealer Ultraschall zur Diagnostik im Mediastinum

Along with endosonographic fine needle aspiration, transoesophageal ultrasonography is now well established for staging gastrointestinal tumors. It is especially well suited to assessing mediastinal structures due to its transoesophageal approach and its high local definition. The mediastinum can be viewed all the way from the tracheal bifurcation to the diaphragm. This technique is already in regular use for pulmonary problems and especially for staging pulmonary carcinomas.

Changes in the myocardial performance index during dobutamine administration in anesthetized cats

To investigate the relationship between myocardial performance index (MPI; also known as the Tei index) and cardiac function in anesthetized cats administered dobutamine. 6 adult cats. Cats were anesthetized by administration of propofol (6 mg/kg, IV), and anesthesia was maintained by administration of isoflurane. Heart rate and systolic arterial pressure (SAP) were monitored. Stroke volume, cardiac output, and aortic blood flow (ABF) were measured by use of transesophageal ultrasonography. Left ventricular fractional shortening (LVFS), mitral E-wave velocity-to-A-wave velocity (E:A) ratio, and ejection time were measured by use of transthoracic echocardiography. Dobutamine was administrated via a cephalic vein at rates of 2.5, 5.0, and 10 microg/kg/min. Heart rate, SAP, cardiac output, and ABF increased with dobutamine administration, whereas stroke volume significantly decreased. The LVFS significantly increased, and the E:A ratio significantly decreased. Total isovolumic time and the MPI significantly decreased. The MPI was negatively correlated (r=-0.63) with LVFS. Conversely, the MPI was positively correlated with the E:A ratio (r=0.47), stroke volume (r=0.66), and total isovolumic time (r=0.95). However, the MPI was not significantly correlated with heart rate, SAP, cardiac output, or ABF. Analysis suggested that the MPI provides a sensitive clinical assessment of cardiac response to medication in cats, which may be similar to the usefulness of the MPI reported in humans.

Long-term survival after excision of a solitary esophageal cancer brain metastasis

Locally advanced esophageal cancer remains a disease with a low long-term cure rate, despite combined modality therapy, because of the frequent presence of occult metastatic disease. Metastatic disease to the central nervous system (CNS) is unusual, with a reported incidence of betwee n0.4 %an d5.1%. 1 Patient swit hesophagea lcance rwh odo present with CNS metastases after initial treatment represent a clinica ldilemma .Althoug hsevera ltreatmen tstrategie susin gradiotherapy, surgical intervention, or both for CNS metastases exist, a poor prognosis is anticipated. We report long-term survival in a patient treated for a locally advanced adenocarcinoma of the esophagus and subsequently for a CNS metastasis. Clinical Summary The patient presented in June 1999 as a 53-year-old healthy white male with dysphagia and a 27-pound weight loss. Endoscopy identified a mass in the distal esophagus from 35 to 39 cm. A biopsy was positive for poorly differentiated adenocarcinoma. No evidence of metastatic disease by means of computed tomographic (CT) scans of the chest and abdomen was found. Transesophageal ultrasonography demonstrated a transmural neoplasm with a cytologically positive celiac lymph node equating to stage IVa disease. He was treated with 4 cycles of cisplatin, 5-fluorouracil, leucovorin, and concurrent radiation (5040 cGy in 28 fractions), which he tolerated well. Repeat CT scans revealed distal esophageal thickening without interval development of metastatic disease. Six weeks after completion of chemoradiation, esophagogastrectomy with en bloc “2-field” (celiac-mediastinal) lymphadenectomy was performed through an Ivor Lewis approach. He was discharged in good condition on the 10th postoperative day. Final pathology demonstrated extensive ulceration of the distal esophagus without evidence of residual neoplasm. Of 17 lymph nodes harvested from the surgical specimen, one had pathologic evidence of necrotic (nonviable) neoplasm, whereas the remainder were found to be free of previous or active disease. Six months after esophagogastrectomy, an acute mild right hemiparesis developed. Magnetic resonance imaging revealed a single 3-cm enhancing mass in the left posterior frontal lobe with surroundin gedem a(Figur e1, A and B) .N oothe revidenc eof recurrent disease on repeat CT scans, as well as endoscopy, was found. The patient underwent craniotomy and complete excision. Pathologic analysis confirmed a poorly differentiated adenocarcinoma with marked necrosis consistent with a metastasis from the primary esophageal neoplasm. He was discharged on the third postoperative day without residual hemiparesis and received adjuvant whole-brain radiation therapy beginning 3 weeks postoperatively (3375 cGy in 15 fractions). He has been carefully followed with CT imaging and endoscopy on a routine basis. The patient remains alive and well 6 years after esophagogastrectomy and 5.5 years after excision of the brain metastasis.

Regarding Manuscript entitled: “EUS-guided FNA of centrally located lung tumours following a non-diagnostic bronchoscopy”: [Annema J.T., Veseliç M, Rabe K.F. Lung Cancer 2005;48(3):357–361

Trans-oesophageal endoscopic ultrasonography (EUS) provides an overview of mediastinal structures, including the para-tracheal space, the sub-carinal region, the aortico-pulmonary window and the para-oesophageal space [1,2]. During the past decade several studies have demonstrated the utility of EUS-guided fine needle aspiration biopsy (EUS-FNA) in lung cancer staging [3—10]. In most of the studies the patients had either an established diagnosis of lung cancer and mediastinal spread (stage T4and/or N2-3 disease) located adjacent to oesophagus suspected by CT, or a solid mediastinal lesion of unknown origin outlined by CT. The reported sensitivity of EUS-FNA in such patients is around 90% for mediastinal malignancy. In addition, some studies have demonstrated, that

Midterm Results of Endoluminal Stent Grafting of the Thoracic Aorta

The purpose of this study was to evaluate the overall outcome of repair of thoracic aortic lesions with endoluminal grafts. Patients were studied prospectively following the implantation of a thoracic endovascular device. Preoperative imaging was performed by helical computed tomography (CT), angiography, transesophageal ultrasonography, or magnetic resonance imaging. Procedures were performed in an endovascular surgical suite under general anesthesia. All patients were evaluated with CT and chest radiography at discharge and at 1, 6, and 12 months. From December 1999 to November 2001, thirty-two patients were enrolled in the study (mean age 62 years; 20 male and 12 female patients). Seventeen patients had dissections, five patients had ruptured aortic ulcer, five patients had traumatic ruptures, three patients had atherosclerotic aneurysms, and two patients had pseudoaneurysms. An American Society of Anesthesiology score of III or IV was evaluated in 22 (69%) patients. The procedure was performed under emergency conditions in 11 cases. All prostheses were implanted successfully. There were no conversions. Three patients (9%) presented with a neurologic event following the implantation procedure, which was lethal in one case (hemorrhagic stroke). Two other patients died during early follow-up of myocardial infarction and multiorgan failure. The early death rate was 9%. The mean follow-up was 13.5 months. During follow-up, the maximal diameter of the aorta shrunk (> or = 5 mm) in 9 (28%) patients, remained stable in 17 (53%) patients, and increased (> or = 5 mm) in 6 (19%) patients. All patients presenting with an increased diameter were initially treated for dissections. A type 1 endoleak was diagnosed on the discharge CT scan in one patient. It sealed spontaneously thereafter. A type 3 endoleak was diagnosed 3 months after the procedure in one patient. A complementary stent graft was implanted in two patients presenting with a dissection with persistent patent false lumen and aortic enlargement. Three patients died during follow-up (two aneurysm-related and one aneurysm-unrelated death). The morbidity and mortality rates reported in our series related to the preoperative morbid conditions of the patients treated. Thoracic aorta endografting is an alternative to open surgery in this subset of patients.

Isquemia aguda por embolia paradójica

Summary Introduction . Paradoxical embolism is a rare event among central or peripheral ischemic phenomena that necessarily require a venous or cardiac thrombotic process together with a right-to-left, usually cardiac, shunt. Correct diagnosis and treatment is fundamental in the management of this infrequent pathology in order to prevent later recurrences. Case report. We describe the case of a 35-year-old female with a history of morbid obesity and four days' continued confinement to bed, who visited because of symptoms of acute ischemia in the upper left limb with loss of all the pulses at that level, and accompanied by dyspnea, hypoxaemia and hypercapnia. Arteriography was performed urgently and revealed an acute ischemic event, probably caused by an embolus, on the subclavian artery and, since concomitant pulmonary embolism was suspected, a pulmonary angiography was carried out that confirmed a massive pulmonary thromboembolism. At the same time, the existence of a right-to-left shunt due to simultaneous filling of the pulmonary artery and aorta was also thought to be likely. The presence of a paradoxical embolism was therefore suspected. No incidences occurred while the embolectomy was being performed and the pulmonary embolism was treated by local fragmentation plus urokinase perfusion for 24 hours with a perioperative stay in the intensive care unit and placement of a temporary vena cava filter. Once the patient's situation was under control, the study then continued with the diagnosis of a patent foramen ovale by means of transesophageal ultrasonography that was closed using a femoral percutaneous approach and placement of an Amplatzer-type occluder (PFO). The patient was discharged from hospital after successfully moving on to oral anticoagulants, since she was at all times under treatment with sodium heparin in perfusion. Conclusions. Paradoxical embolism accounts for only a very small percentage of all cases of acute ischemia. Yet, the clinician must suspect its existence when faced with atypical cases of ischemic episodes, whether they are associated or not with deep vein thrombosis, and each situation must always be evaluated separately, given the absence of a defined strategy for dealing with this unusual pathology. [ANGIOLOGIA 2004; 56: 571-8]

Measurement of cardiac output by transesophageal Doppler ultrasonography in anesthetized dogs: comparison with thermodilution

Thermodilution (TD) is the standard method for cardiac output (CO) monitoring in human medicine. Although called the ‘gold standard’, TD is related to numerous complications and data misinterpretations. Recently, a noninvasive, continuous, ultrasound-based technique for CO measurement has been developed (Hemosonic 100, Arrow Intl). This study compared transesophageal Doppler ultrasonography (TED) for measuring CO with TD in anesthetized dogs. In this study, ten dogs were used to simultaneously measure CO by TED and TD. All dogs were pre-medicated with acepromazine at 0.1 mg kg−1 IM, induced with thiopental at 10 mg kg−1 IV, and maintained on isoflurane at end-tidal concentrations of 1.3%. Baseline and four different levels of CO were used for comparison. Low CO levels were induced by caudal vena cava occlusion. High CO levels were induced by the constant IV infusion of dopamine, dobutamine, or norepinephrine. Each level of CO allowed one comparison between TED and TD. Forty-nine paired comparisons of CO were determined ranging from 0.73 to 10.9 L minute−1. Simple linear regression was used to determine the correlation between the two techniques. Correlation coefficient (r2) was 0.53. Bland and Altman statistical method was used for assessing agreement between the two methods. The difference between the TD and TED when all data were included was 0.82 (bias) ± 1.63 L minute−1 (mean ± SD). At low CO levels (baseline and caudal vena cava occlusion), the correlation coefficient was 0.77, bias was 0.35 ± 0.64 L minute−1. At high CO levels (dopamine, dobutamine, or norepinephrine), the correlation coefficient was 0.39. It was concluded that TED was not a reliable monitoring method in determining CO when positive inotropes were used. TED might have importance in situations of low CO values; however, further investigation is warranted.

Intraoperative transesophageal ultrasonography can measure renal blood flow

Objective: To determine the feasibility of acquiring Doppler-derived indices of renal blood flow by transesophageal ultrasonography in the perioperative period. Design: Prospective, sequential, institutional review board—approved study. Setting: University teaching hospital. Participants: Nine patients with normal renal function, scheduled for elective primary coronary artery bypass graft surgery. Interventions: Two-dimensional images of renal parenchyma and Doppler measurement of intrarenal arterial blood flow during internal mammary dissection were acquired. To effect renal blood flow changes, the renal vasodilator dopamine, 2 μg/kg/min, was infused for 20 minutes after baseline measurements were made. Renal Doppler measurements were repeated to determine whether transesophageal ultrasonography can follow these changes. Measurements and Main Results: Hemodynamic measurements (heart rate, mean arterial blood pressure, cardiac output, and cardiac index) and Doppler velocity measurements of intrarenal arterial blood flow (peak systolic, end-diastolic, and mean velocity) were made at time 1 (T1 = baseline) and at time 2 (T2 = after 20 minutes of dopamine infusion). The derived Doppler indices, pulsatility index and resistive index, were calculated according to standard formulae. Measurements were compared by paired Student's t-test (two-tailed, p < 0.05, significant). There were no statistical differences between cardiac index (2.10 ± 0.93 L/min/m2v 2.21 ± 0.92 L/min/m2, p = 0.254) and mean arterial pressure (82.3 ± 11.2 mmHg v 83.3 ± 14.5 mmHg, p = 0.872) between T1 and T2. Systolic renal velocity increased from 44.7 ± 13.0 cm/s to 63.0 ± 20.4 cm/s (p = 0.005), diastolic velocity increased from 12.7 ± 4.0 cm/s to 22.4 ± 7.8 cm/s (p = 0.0003), and mean velocity increased from 22.5 ± 6.6 cm/s to 34.1 ± 11.7 cm/s (p = 0.003) after infusion of dopamine. These results indicate an increase in renal blood flow from baseline values. The pulsatility index decreased from 1.44 ± 0.29 to 1.21 ± 0.24 (p = 0.0005), whereas the resistive index decreased from 0.71 ± 0.06 to 0.64 ± 0.06 (p = 0.0004) after dopamine. Reductions in pulsatility and resistive indices indicate a reduction in renal vascular resistance. Conclusion: This study demonstrates the ability to acquire two-dimensional images of kidney and renal arterial Doppler velocities using transesophageal ultrasonography during cardiac surgery. Transesophageal renal arterial Doppler waveform analysis can follow changes in renal blood flow patterns secondary to interventional therapy. Copyright © 2001 by W.B. Saunders Company

The Echocardiographic Diagnosis, Characterization, and Extraction Guidance of Cardiac Foreign Bodies

Echocardiography is ideal for localizing cardiac foreign bodies and for characterizing associated cardiac and vascular injury before and during extraction. We report 5 cases of traumatic and iatrogenic cardiac foreign bodies that illustrate the central role of transthoracic and transesophageal ultrasonography in the management of these patients.

The echocardiographic diagnosis, characterization, and extraction guidance of cardiac foreign bodies

Echocardiography is ideal for localizing cardiac foreign bodies and for characterizing associated cardiac and vascular injury before and during extraction. We report 5 cases of traumatic and iatrogenic cardiac foreign bodies that illustrate the central role of transthoracic and transesophageal ultrasonography in the management of these patients.

Transesophageal ultrasonography of the normal canine mediastinum.

The mediastinum of eight normal research dogs was examined by transesophageal ultrasonography with a 5 MHz frequency transducer to establish a baseline for future use of this new imaging modality as a diagnostic tool. Each examination consisted of 360 degree scans in both transverse and sagittal planes from the thoracic inlet to the esophageal hiatus. Dissections of four of these research dogs were then performed to confirm transesophageal ultrasonography findings. Transesophageal ultrasonography of the mediastinum was a good imaging modality for the evaluation of the heartbase, the major cranial mediastinal vessels, the descending aorta, and occasionally part of the azygos vein. Anatomic orientation was best obtained by beginning the examination at the heart base. Lymph nodes and smaller caliber vessels could not be distinguished from surrounding tissues; however, Doppler ultrasound was useful for identifying the smaller vessels. Although a 5 MHz frequency transducer is preferred for transesophageal echocardiography, a higher frequency transducer would improve the resolution of the images of small near-field structures and may be more appropriate for mediastinal imaging.

Upright posture decreases esophageal varices flow velocity in patients with cirrhosis

Background/Aims: Patients with cirrhosis tend to have esophageal variceal bleeding episodes at night, rather than during the day time. Since human beings carry on ordinary activities in the upright posture in the day time and are recumbent at night, we hypothesized that posture may be a factor related to a circadian variation of variceal bleeding. The aim of this study was to examine the effect of upright posture on esophageal varices hemodynamics in patients with cirrhosis. Methods: Nine patients with cirrhosis and esophageal varices were included in a crossover study performed on 2 separate days. On the non-endoscopic day, cardiac output, portal vein flow velocity, and superior mesenteric artery flow velocity were measured with percutaneous Doppler ultrasonography. Plasma renin activity and plasma norepinephrine concentrations were also determined. On the endoscopic day, in addition to the above measurements, esophageal varices flow velocity was measured using transesophageal Doppler ultrasonography. These measurements were performed in the supine position and 20 min after the assumption of the upright position. Results: On the non-endoscopic day, the upright posture significantly decreased cardiac output, portal vein flow velocity, and superior mesenteric artery flow velocity. Plasma renin activity and plasma norepinephrine concentration were significantly increased after assumption of the upright position. On the endoscopic day, similar hemodynamic and hormonal changes were observed. In addition, the upright posture significantly decreased esophageal varices flow velocity. Furthermore, the magnitude of the reduction in esophageal varices flow velocity (−42%) was significantly greater than that in portal vein flow velocity (−22%, p<0.01) and that in superior mesenteric artery flow velocity (−25%, p<0.01). Although the change in esophageal varices flow velocity was not significantly correlated with that in plasma renin activity ( r=−0.28) and that in plasma norepinephrine concentration ( r=−0.10), it was significantly correlated with the change in superior mesenteric artery flow velocity ( r=0.73, p<0.05). Conclusions: The upright posture decreases esophageal varices flow velocity mainly because of the reduction in splanchnic blood flow. This effect may contribute to a low prevalence of esophageal variceal bleeding in the day time in patients with cirrhosis

Transesophageal Ultrasonographic Imaging in Rat Hearts: Visualization of Aortic Valve Vegetations in Non-Bacterial Thrombotic Endocarditis

The aim of this study was to test the feasibility of transesophageal ultrasonography in rats by using an intravascular ultrasound system for visualization of vegetations at the aortic valve in the animal model of experimental endocarditis. After anesthesia and preparation of the right carotid artery, a polyethylene catheter was advanced across the aortic valve into the left ventricle in 91 rats. For transesophageal ultrasonography an intravascular ultrasound catheter (3.5 French; 30 MHz) linked to an imaging system was introduced into the esophagus. Sonographic investigations were performed every 24 hours until death. The presence, size, and echogenicity of vegetations were evaluated. Presence and size were compared to autopsy findings. No complications occurred as a result of the sonographic investigation. Left-sided valvular structures were imaged regularly. For detection of vegetations, sensitivity and specificity were 93% and 88%, respectively. Comparing the measurements of the vegetation size the following regression equation was obtained: y = 0.74x + 0.04 ( r = 0.89; standard error of estimate = 0.02 cm). Inter- and intraobserver variabilities for sonographic measurements were 8.3% and 6.2%, respectively. Transesophageal ultrasonography permits reliable detection and repetitive accurate quantification of vegetations in the rat model of endocarditis. The technique enhances longitudinal studies of the dynamic process of the growth of vegetations under defined microbial conditions.(J Am Soc Echocardiogr 1998;11:201–5.)