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Biomedical subjects

W F Walsh

Publications and source records attributed to W F Walsh.

At least 37 records · Page 2Linked to original sources
PubMed1994

Role of transoesophageal echocardiography in the diagnosis and management of aortic root abscess.

OBJECTIVE: To assess and compare the roles of transthoracic and transoesophageal echocardiography in the diagnosis and management of an aortic root abscess. DESIGN: To select patients with echocardiographic diagnosis of aortic valve endocarditis with and without an aortic root abscess and correlate this with a retrospective review of surgical and necropsy data. SETTING: Tertiary referral centre at a university teaching hospital. PATIENTS AND METHODS: 34 patients with confirmed aortic valve endocarditis were treated over a four and a half year period. All patients underwent both transthoracic and transoesophageal echocardiography with 17 patients having biplane or multiplane imaging. RESULT: 11 patients (32%) had an aortic root abscess. Transthoracic echocardiography identified four cases of aortic root abscess whereas transoesophageal echocardiography correctly detected all 11 cases and also detected complications including mitral aortic intervalvar fibrosa fistula in two patients and right atrial involvement in another two patients. Only biplane imaging was able to show an anterior aortic root abscess in one patient and the circumferential involvement of the aortic annulus in another two patients. All patients with an aortic root abscess were treated surgically after transoesophageal echocardiographic diagnosis. After operation, prosthetic aortic regurgitation was present in seven patients and a repeat operation was performed in three patients. Only transoesophageal echocardiography detected a postoperative aorto-right atrial fistula in two patients and recurrence of the root abscess in another. There were five deaths in hospital (45%). CONCLUSIONS: Compared with transthoracic echocardiography, transoesophageal echocardiography was more sensitive and more specific for the early diagnosis of aortic root abscess and its complications and facilitated both the preoperative and postoperative management of these patients. Biplane and multiplane imaging provide additional diagnostic information. All patients with suspected aortic valve endocarditis should have an early transoesophageal echocardiographic study.

Abscess↗
PubMed1994

Exclusion of atrial thrombus by transesophageal echocardiography does not preclude embolism after cardioversion of atrial fibrillation. A multicenter study.

BACKGROUND: Transesophageal echocardiography (TEE) has been used recently to detect atrial thrombi before cardioversion of atrial arrhythmias. It has been assumed that embolic events after cardioversion result from embolism of preexisting atrial thrombi that are accurately detected by TEE. This study examined the clinical and echocardiographic findings in patients with embolism after cardioversion of atrial fibrillation despite exclusion of atrial thrombi by TEE. METHODS AND RESULTS: Clinical and echocardiographic data in 17 patients with embolic events after TEE-guided electrical (n = 16) or pharmacological (n = 1) cardioversion were analyzed. All 17 patients had nonvalvular atrial fibrillation, including four patients with lone atrial fibrillation. TEE before cardioversion showed left atrial spontaneous echo contrast in five patients and did not show atrial thrombus in any patient. Cardioversion resulted in return to sinus rhythm without immediate complication in all patients. Thirteen patients had cerebral embolic events and four patients had peripheral embolism occurring 2 hours to 7 days after cardioversion. None of the patients were therapeutically anticoagulated at the time of embolism. New or increased left atrial spontaneous echo contrast was detected in four of the five patients undergoing repeat TEE after cardioversion including one patient with a new left atrial appendage thrombus. CONCLUSIONS: Embolism may occur after cardioversion of atrial fibrillation in inadequately anticoagulated patients despite apparent exclusion of preexisting atrial thrombus by TEE. These findings suggest de novo atrial thrombosis after cardioversion or imperfect sensitivity of TEE for atrial thrombi and suggest that screening by TEE does not obviate the requirement for anticoagulant therapy at the time of and after cardioversion. A randomized clinical trial is needed to compare conventional anticoagulant management with a TEE-guided strategy including anticoagulation after cardioversion.

Adult↗
PubMed1993

Evaluation of transesophageal echocardiography before cardioversion of atrial fibrillation and flutter in nonanticoagulated patients.

This study prospectively evaluated the role of transesophageal echocardiography (TEE) in screening for atrial thrombi before electrical cardioversion in 40 nonanticoagulated patients with nonvalvular atrial fibrillation (n = 33) or atrial flutter (n = 7). Transthoracic echocardiography did not detect atrial thrombus in any patient. TEE detected left atrial appendage thrombi in five patients (12%, p = 0.03), significantly associated with left ventricular systolic dysfunction (p = 0.02) and left atrial spontaneous echo contrast (p = 0.04). Cardioversion was cancelled in the five patients with thrombi and in two patients with spontaneous reversion before planned cardioversion. Cardioversion was successful in 25 (76%) of the 33 remaining patients. Cerebral embolism occurred 24 hours after successful cardioversion in one patient with atrial fibrillation and left ventricular dysfunction, who had left atrial spontaneous echo contrast, but no thrombus was detected by TEE before cardioversion. Repeat TEE after embolism showed a fresh left atrial appendage thrombus and increased left atrial spontaneous echo contrast. These results indicate that TEE improves the detection of left atrial appendage thrombi in candidates for cardioversion, in whom the procedure may be deferred. However, the exclusion by TEE of preexisting atrial thrombi before cardioversion does not eliminate the risk of embolism after cardioversion because of persistent atrial stasis and de novo thrombosis.

Anticoagulants↗
PubMed1993

Hematologic correlates of left atrial spontaneous echo contrast and thromboembolism in nonvalvular atrial fibrillation.

OBJECTIVES: This study examined the relation between left atrial spontaneous echo contrast, hematologic variables and thrombo-embolism in patients with nonvalvular atrial fibrillation. BACKGROUND: Left atrial spontaneous echo contrast is associated with left atrial stasis and thromboembolism in patients with nonvalvular atrial fibrillation. However, its hematologic determinants in patients with nonvalvular atrial fibrillation are unknown. METHODS: Clinical, hematologic and echocardiographic variables were prospectively measured in 135 consecutive patients with nonvalvular atrial fibrillation undergoing transesophageal echocardiography. RESULTS: Patients with left atrial spontaneous echo contrast (n = 74, 55%) had an increased fibrinogen concentration (p = 0.029), platelet count (p = 0.045), hematocrit (p = NS) and left atrial dimension (p = 0.005). Multivariate analysis showed that left atrial spontaneous echo contrast was independently related to hematocrit (odds ratio = 2.24, p = 0.002), fibrinogen concentration (odds ratio = 2.08, p = 0.008) and left atrial dimension (odds ratio = 1.90, p = 0.004) but not platelet count. It was also associated with left atrial thrombus (n = 15, p = 0.001) and with recent embolism (n = 40, p < 0.001). In 40 clinically stable outpatients without previous embolism, left atrial spontaneous echo contrast was significantly related to hematocrit (p = 0.005), fibrinogen concentration (p = 0.035) and left atrial dimension (p = 0.029) but not to coagulation factor VII, D-dimer, erythrocyte sedimentation rate, platelet count, plasma beta-thromboglobulin, plasma glycocalicin or glycocalicin index. CONCLUSIONS: Left atrial spontaneous echo contrast in patients with nonvalvular atrial fibrillation is independently related to hematocrit, fibrinogen concentration and left atrial dimension, indicating a relatively hypercoagulable state in addition to stasis. These findings support the hypothesis that left atrial spontaneous echo contrast is due to erythrocyte aggregation. Hematologic factors may contribute to its association with thromboembolism.

Aged↗
PubMed1993

Induction of human neonatal pulmonary fibroblast cytokines by hyperoxia and Ureaplasma urealyticum.

Multiple insults may induce bronchopulmonary dysplasia (BPD) in premature infants, including the recently reported association of BPD with neonatal Ureaplasma urealyticum colonization. One mechanism of damage could involve stimulation of proinflammatory cytokine release from pulmonary fibroblasts. We therefore compared the effects of U. urealyticum, oxygen, and lipopolysaccharide (LPS) on the release of interleukin (IL)-1 beta, IL-6, and IL-8 from neonatal fibroblasts. Fibroblasts were grown in multiwell plates and divided into the following experimental conditions: fibroblasts alone, fibroblasts plus U. urealyticum (10,000 cfu/mL), and fibroblasts plus LPS (2 micrograms/mL). Plates were then exposed to room air or hyperoxia for 48 h, and supernatants were assayed for IL. U. urealyticum-infected fibroblasts produced a significant increase in IL-6 (P < .05) and a dramatic increase in IL-8 (P < .05) that was independent of hyperoxic exposure and significantly increased over that produced by LPS or hyperoxia alone. U. urealyticum is a potent inducer of fibroblast cytokine release in vitro and may contribute to the development of BPD.

Bronchopulmonary Dysplasia↗
PubMed1993

A primate model of Ureaplasma urealyticum infection in the premature infant with hyaline membrane disease.

Cultures positive for Ureaplasma urealyticum in babies weighing < 1000 g have been associated with both chronic lung disease (CLD) and death, but no definite causality has been established. To further investigate the role of the organism in CLD, we colonized premature baboons with U. urealyticum and compared resulting pathology with that in uninoculated control animals. Using an established model of prematurity, the 140-day-gestation baboon, three animals were colonized with U. urealyticum via endotracheal tube. All had hyaline membrane disease, indistinguishable from disease in human infants, and U. urealyticum infection. Samples obtained from nasopharynx, trachea, pleural fluid, and, at necropsy, lung tissue produced positive cultures. Culture of blood from one animal yielded U. urealyticum. On pathologic examination, after 6 days of ventilation, all three of the infected animals had the specific pathologic finding of bronchiolitis with epithelial ulceration not seen in four uninfected control animals. Thus, U. urealyticum is capable of causing a pathologically recognizable pulmonary lesion in premature primates with hyaline membrane disease.

Animals↗
PubMed1992

Transoesophageal echocardiography in heart disease--old technologies, new tricks.

Cardiac ultrasound and upper gastrointestinal endoscopy are relatively old technologies. With the introduction of new ultrasound probes and by incorporating ultrasound technology into conventional endoscopes, 'new tricks' in cardiac imaging were discovered. Posterior structures of the heart are now able to be imaged clearly by the ultrasound probe from the oesophagus. Consequently, better resolution of cardiac anatomy allows more accurate diagnosis of cardiac pathologies which is not possible using conventional transthoracic (TT) approach. Over a period of two years, 1200 cases of transoesophageal echocardiography (TOE) were undertaken in our institution. The major indications were diseases of the aorta (10%), source of cardioembolism (28%), assessment of native and prosthetic valve function (20%), suspected endocarditis and its complication (17%), pre and post percutaneous transluminal mitral valvotomy (PTMV [13%], congenital heart disease (2%) and others (10%). The greatest impact with TOE is in the diagnosis of aortic dissection and transection. TOE is superior to conventional TT approach in detecting potential source of embolism, valvular vegetations and its complication, native and prosthetic valve dysfunction and LA thrombus prior to PTMV. Observations by TOE such as spontaneous echo contrast (SEC) in the left atrium open new challenges for further research in its role in the pathogenesis of LA thrombus and its association with cardioembolic event. Other areas of interest include; reclassification of distal aortic dissection and the use of TOE in intra-operative work.

Aortic Diseases↗
PubMed1992

Surfactant lavage in a piglet model of meconium aspiration syndrome.

Meconium aspiration continues to be a major cause of morbidity and mortality in newborn infants and is one of the most common indications for extracorporeal membrane oxygenation. Lab studies have suggested that meconium inactivates surfactant and displaces surfactant from the alveolar surface. A recent report has suggested a clinical role for surfactant therapy in human infants with meconium aspiration. We evaluated the effect of surfactant (Survanta) lavage on a piglet model of meconium aspiration. Meconium pneumonitis was created by administration of 4 mL/kg of a 20% slurry of human meconium via endotracheal tube. Twenty-four newborn piglets were then randomly assigned to one of three groups: 1) suction only (n = 7), 2) saline lavage (n = 5), or 3) surfactant lavage (n = 7). Five piglets were excluded from analysis due to death from pneumothorax during meconium administration (n = 3), death from pneumothorax during saline lavage (n = 1), and death from pneumothorax during surfactant lavage (n = 1). The surfactant group had a statistically significant (p less than 0.05) improvement in arterial to alveolar oxygen ratio gradient versus both control groups for the first 3 h. The oxygenation index was statistically significant versus the suction only group at 1, 3, and 4 h. Surfactant lavage of meconium aspiration in piglets results in short-term improvement of oxygenation and warrants further study.

Animals↗
PubMed1991

Left atrial spontaneous echo contrast: a clinical and echocardiographic analysis.

The clinical and echocardiographic variables related to left atrial spontaneous echo contrast were prospectively evaluated in a consecutive series of 400 patients undergoing transesophageal echocardiography with a 5-MHz single plane transducer. Left atrial spontaneous echo contrast was found in 75 patients (19%) and was significantly associated with atrial fibrillation, mitral stenosis, absence of mitral regurgitation, increased left atrial dimension and a history of suspected embolism. Seventy-one (95%) of the patients with spontaneous echo contrast had atrial fibrillation or mitral stenosis. Anticoagulant therapy had no significant association with spontaneous echo contrast. Multivariate analysis in 89 patients with mitral stenosis or mitral valve replacement showed that spontaneous echo contrast was the only independent predictor (p = 0.03) of left atrial thrombus or suspected embolism, or both. In 60 patients with atrial fibrillation of nonvalvular origin, spontaneous echo contrast (p = 0.01) and age (p = 0.03) were the only independent predictors of left atrial thrombus or suspected embolism, or both. It is concluded that left atrial spontaneous echo contrast is 1) a common finding in patients undergoing transesophageal echocardiography, 2) associated with conditions favoring stasis of left atrial blood, and 3) a marker of previous thromboembolism in patients with nonvalvular atrial fibrillation and those with mitral stenosis or mitral valve replacement.

Atrial Fibrillation↗
PubMed1991

Ureaplasma urealyticum demonstrated by open lung biopsy in newborns with chronic lung disease.

Lung biopsy tissue from eight infants with chronic lung disease was evaluated for the presence of Ureaplasma urealyticum. Specimens from four infants grew the organism. Pleural fluid cultures matched lung tissue but tracheal cultures were negative in two babies with positive lung tissue. There were no distinguishing pathologic findings in the four culture-positive infants which could be used to identify them vs. the culture-negative infants. Three culture-positive infants improved clinically after therapy directed at Ureaplasma even though two remained culture-positive. Ureaplasma grows in lung tissue of infants with chronic lung disease, it does not demonstrate any specific standard pathologic findings and tissue cultures do not match endotracheal cultures.

Biopsy↗
PubMed1991

Role of transoesophageal echocardiography in evaluation of cardiogenic embolism.

OBJECTIVE: To determine the value of transoesophageal echocardiography in the assessment of selected patients at risk of cardiogenic embolism or after it. DESIGN: Prospective comparison of the results of transoesophageal and transthoracic echocardiography. Transoesophageal echocardiography was performed with a 5 MHz single plane phased array transducer. SETTING: University teaching hospital. PATIENTS: 100 patients referred for transoesophageal echocardiography after a cerebral ischaemic event or peripheral arterial embolism (n = 63), before percutaneous balloon dilatation of the mitral valve (n = 23), or before electrical cardioversion of atrial fibrillation (n = 14). RESULTS: Transthoracic echocardiography showed potential sources of embolism in four patients including left ventricular thrombus in two patients (with one false positive), left atrial appendage thrombus (n = 1), and patent foramen ovale (n = 1). Transoesophageal echocardiography showed 59 potential embolic sources in 45 patients including left atrial spontaneous echo contrast (n = 33), left atrial appendage thrombus (n = 13), left ventricular thrombus (n = 5), patent foramen ovale (n = 3), left ventricular spontaneous echo contrast (n = 2), mitral valve prosthesis thrombus (n = 1), mitral valve prolapse (n = 1), and pronounced aortic atheroma (n = 1). Transoesophagal echocardiography showed potential embolic sources in 36/53 (68%) patients with atrial fibrillation compared with 9/47 (19%) patients in sinus rhythm. Percutaneous balloon dilatation of the mitral valve was performed without embolic complications in 18 patients without left atrial thrombi and in three patients with small fixed thrombi in the left atrial appendage. It was cancelled in two patients with large thrombi in the left atrial appendage. Cardioversion was performed without embolic complications in 14 patients without left atrial thrombi. CONCLUSIONS: Transoesophageal echocardiography detects potential sources of embolism better than transthoracic echocardiography in selected patients at risk of cardiogenic embolism or after it.

Adult↗
PubMed1991

A randomized comparison of intravenous heparin with oral aspirin and dipyridamole 24 hours after recombinant tissue-type plasminogen activator for acute myocardial infarction. National Heart Foundation of Australia Coronary Thrombolysis Group.

BACKGROUND: This study addressed the need for heparin administration to be continued for more than 24 hours after coronary thrombolysis with recombinant tissue-type plasminogen activator (rt-PA). METHODS AND RESULTS: A total of 241 patients with acute myocardial infarction were treated with 100 mg rt-PA and a bolus of 5,000 units i.v. heparin followed by 1,000 units/hr i.v. heparin for 24 hours. At 24 hours, 202 patients were randomized to continue intravenous heparin therapy (n = 99) in full dosage or to discontinue heparin therapy and begin an oral antiplatelet regimen of aspirin (300 mg/day) and dipyridamole (300 mg/day) (n = 103). On prospective recording, there were no differences in the pattern of chest pain, reinfarction, or bleeding complications. Coronary angiography on cardiac catheterization at 7-10 days showed no differences in patency of the infarct-related artery. The proportion of patients with total occlusion (TIMI grade 0-1) of the infarct-related artery was 18.9% in the heparin group and 19.8% in the aspirin and dipyridamole group. In the patients with an incompletely occluded infarct-related artery, the lumen was reduced by 69 +/- 2% of normal in the heparin group and 67 +/- 2% in the aspirin and dipyridamole group. Left ventricular function assessed on cardiac catheterization and radionuclide study at day 2 and at 1 month showed no differences between the two groups. Left ventricular ejection fraction on radionuclide ventriculography at 1 month was 52.4 +/- 1.2% in the heparin group and 51.9 +/- 1.2% in the aspirin and dipyridamole group. CONCLUSIONS: We conclude that heparin therapy can be discontinued 24 hours after rt-PA therapy and replaced with an oral antiplatelet regimen without any adverse effects on chest pain, reinfarction, coronary patency, or left ventricular function.

Administration, Oral↗
PubMed1990

The clinical role of transoesophageal echocardiography.

The role of transoesophageal echocardiography (TEE) was evaluated in a consecutive series of 100 procedures performed in 86 patients (age 17-81, mean 56 years). All patients had prior transthoracic echocardiography (TTE). TEE was performed with a 5 MHz phased array transoesophageal transducer with pulsed wave Doppler and colour flow mapping capability. Forty-four per cent of patients received intravenous sedation and 36% received antibiotic prophylaxis. There were no complications of TEE. The TTE and TEE findings were compared. In patients referred for possible cardiac source of embolism, left atrial thrombi were detected in 8/27 TEE studies but in none of 27 TTE studies. In 12 patients with prosthetic valve dysfunction TEE distinguished prosthetic from periprosthetic regurgitation in 9/12 studies compared to 3/12 with TTE. In 11 patients with suspected aortic dissection TEE correctly detected dissection in all seven cases in which the diagnosis was subsequently confirmed, whereas TTE showed only equivocal findings in two cases. Vegetations were detected by TEE in 4/5 studies in patients with proven native valve endocarditis and by TTE in 2/5. No vegetations were detected by TTE or TEE in five studies in patients with proven prosthetic valve endocarditis. Compared with other investigations there were no false positive TEE studies and one possible false negative study. We conclude that TEE is a safe procedure which often provides additional clinical information to transthoracic echocardiography.

Adolescent↗
PubMed1989

Left ventricular volumes in moderate alcohol users: a study from the workplace.

We measured resting and exercise left ventricular volumes by a count-based, nongeometric radionuclide method in 23 healthy volunteers grouped according to reported average daily alcohol consumption: 0-20 g (Gp A), 21-50 g (Gp B) and greater than 50 g (Gp C). No patient had measurable alcohol in his blood at the time of study. Mean resting LV Ejection Fraction (EF) was 65 +/- 2% in Group A, 64 +/- 2% in Group B, and 65 +/- 3% in Group C. Exercise EF was 76 +/- 1,75 +/- 3 and 74 +/- 4%, respectively. Resting Endsystolic Volume Indices in the three groups were 19.2 +/- 3, 18.9 +/- 2 and 21.8 +/- 3 ml/m2; exercise values were 15.9 +/- 2, 12.8 +/- 2 and 13.3 +/- 2 ml/m2, respectively. This cohort was selected for absence of markers of alcohol-related illness, and all subjects were employed. We found no evidence for impaired left ventricular systolic function with moderate alcohol usage using a sensitive radionuclide technique.

Adult↗