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Biomedical subjects

B Barzilai

Publications and source records attributed to B Barzilai.

At least 19 recordsLinked to original sources
PubMed1992

Frequency and significance of intrapulmonary right-to-left shunting in end-stage hepatic disease.

Intrapulmonary vascular abnormalities consisting of arteriovenous malformations and capillary dilatations have been described in patients with severe liver disease. These intrapulmonary vascular abnormalities can result in intrapulmonary right-to-left shunting and hypoxemia. Twenty-five of 53 patients (47%) with end-stage hepatic disease were found to have contrast echocardiographic evidence of intrapulmonary right-to-left shunting. There was no difference in mean age, gender distribution, or severity of hepatic disease in those with and without evidence of such shunting. Although there was no difference in mean partial arterial oxygen pressure (PaO2) values in the 2 groups (82 +/- 11 vs 76 +/- 11 mm Hg), the mean PaO2 value of those with at least 2+ left ventricular opacification (2 to 4+) was significantly lower (66 +/- 3 mm Hg, n = 8; p less than 0.01). Unexpectedly, patients with evidence of intrapulmonary shunting had a lower mortality rate before transplantation (3 of 25, 12%) than those without evidence of shunting (10 of 28, 36%) resulting in a significant difference in actuarial survival (p less than 0.05) by the end of the follow-up period. It is concluded that intrapulmonary right-to-left shunting occurs frequently in patients with end-stage liver disease and may be a marker of a positive biologic process that, in some way, leads to improved short-term survival.

Adult↗
PubMed1992

Quantitative ultrasonic imaging: tissue characterization and instantaneous quantification of cardiac function.

Quantitative myocardial tissue characterization is being developed to complement and expand conventional echocardiography by delineating the physical state of myocardium under diverse pathophysiologic conditions. Real-time quantitative integrated backscatter imaging has already been applied to patients with ischemic heart disease, hypertrophic cardiomyopathy, and cardiac allograft rejection in clinical investigations performed in the United States, Europe, and Japan. A recently introduced modification of imaging processing algorithms employed for characterization of tissue facilitates automatic detection of endocardial-blood interfaces and on-line quantification of ventricular size and function. Further progress and anticipated developments in quantitative ultrasonic imaging will undoubtedly augment the clinical applications of tissue characterizations based on myocardial integrated backscatter for improved diagnosis, elucidation of pathophysiology, and assessment of cardiac function.

Animals↗
PubMed1992

Importance of left ventricular function and systolic ventricular interaction to right ventricular performance during acute right heart ischemia.

To determine whether modulation of systolic ventricular interaction influences right ventricular performance during right heart ischemia, the effects of septal ischemia and inotropic stimulation were studied in 15 dogs in an open chest preparation. Right coronary branch occlusions led to right ventricular dilation and free wall dyskinesia, reversed septal curvature and reduced left ventricular diastolic volume. In systole, the septum thickened but bulged paradoxically into the right ventricle generating an active but depressed right ventricular systolic pressure (28.9 +/- 5.5 to 22.1 +/- 4.5 mm Hg), with associated decreases in right ventricular stroke work (5.66 +/- 0.94 to 1.92 +/- 0.53 g.m/m2) and left ventricular systolic pressure (123 +/- 11 to 80 +/- 10 mm Hg). Septal ischemia induced systolic septal thinning, left ventricular dilation and decreased left ventricular systolic pressure (80 +/- 10 to 55 +/- 10 mm Hg) and stroke work. Although the extent of paradoxic septal displacement increased, there were further decrements in right ventricular systolic pressure (22.1 +/- 4.5 to 18.7 +/- 4.3 mm Hg) and stroke work (1.92 +/- 0.53 to 0.7 +/- 0.2 g.m/m2). Dopamine infusion augmented left ventricular free wall contraction and increased left ventricular systolic pressure (55 +/- 10 to 172 +/- 17 mm Hg) and stroke work. Although systolic septal thinning persisted, the extent of paradoxic septal displacement increased strikingly and, despite continued right ventricular free wall dyskinesia, right ventricular systolic pressure increased (18.7 +/- 4.3 to 39.6 +/- 6.2 mm Hg) as did right ventricular stroke work (0.7 +/- 0.2 to 7 +/- 1.6 g.m/m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1992

Intraoperative echocardiographic diagnosis of previously unrecognized cor triatriatum.

Cor triatriatum is a congenital heart defect resulting in abnormal septation of the left atrium by a fibromuscular membrane. Echocardiography has improved the preoperative diagnosis of this rare congenital heart defect. We report a case where transesophageal echocardiography proved useful in the intraoperative diagnosis of a previously undetected cor triatriatum.

Aged↗
PubMed1992

On-line assessment of ventricular function by automatic boundary detection and ultrasonic backscatter imaging.

To provide an approach suitable for on-line analysis of ventricular function, a conventional two-dimensional ultrasound imaging system was modified to detect and track blood-tissue interfaces in real time based on their quantitative acoustic properties. This modification permitted on-line display of the left ventricular cavity area, fractional area change, volumes and ejection fraction on a beat by beat basis. Images were obtained from 54 patients and 12 normal subjects with broad ranges of ventricular dimensions and systolic function. On-line measurements of cavity areas were compared with off-line measurements of cavity areas (analysis of videotaped conventional images). Left ventricular cavity areas measured on-line from short-axis views correlated closely with off-line views as did areas from apical views. On-line fractional area change correlated well with ejection fraction calculated off-line. More than 70% of patients could be studied adequately with the approach developed. Thus, automatic boundary detection based on quantitative assessment of tissue acoustic properties permits on-line quantitation of ventricular cavity areas and indexes of function.

Algorithms↗
PubMed1992

Detection of the source of arterial emboli by transesophageal echocardiography: a case report.

We report a case acute lower extremity ischemia caused by emboli in which the initial diagnostic evaluation, including standard aortoiliofemoral arteriography and routine transthoracic two-dimensional echocardiography, failed to reveal the offending source. Because of the strong clinical suspicion that the origin of the arterial occlusion was embolic, transesophageal echocardiography was performed. Transesophageal echocardiography demonstrated an aortic valvular lesion and cardiac surgery was performed on an emergency basis. The use of transesophageal echocardiography in evaluating the heart and thoracic aorta as a source of distal emboli is also discussed.

Aortic Valve↗
PubMed1992

Factors related to end-systolic volume are important determinants of peak early diastolic transmitral flow velocity.

BACKGROUND: Three important determinants of left ventricular (LV) peak early diastolic filling rate, which is related directly to the magnitude of the transmitral pressure difference, are the rate of LV isovolumic pressure fall (T1/2), left atrial (LA) pressure at mitral valve opening (X1), and end-systolic volume (ESV). METHODS AND RESULTS: To delineate the relative degrees to which these factors contribute to the magnitude of peak early diastolic filling rate, we measured LA and regional intra-LV pressures with micromanometers, LV volume with contrast angiography, and peak transmitral flow velocity (E) with transesophageal Doppler echocardiography in 16 anesthetized closed-chest dogs. E did not correlate significantly with either X1 (r = -0.255) or T1/2 (r = -0.281). Multivariate analysis, with E entered as the dependent variable and X1 and T1/2 as independent variables, also failed to reach significance (R = 0.310). E correlated significantly with ESV (r = -0.633, p less than 0.009). Using multivariate analysis, the major determinants of ESV were found to be LV contractility (+dP/dt), afterload (aortic diastolic pressure, AOdias), and preload (end-diastolic volume, EDV) (R = 0.848, p less than 0.001). E correlated significantly with two of the determinants of ESV (+dP/dt and AOdias) (R = 0.906, p less than 0.001); however, the addition of EDV did not significantly improve the multivariate relation (R = 0.911). To determine whether X1 or T1/2 would add significantly to the above multivariate relation, these factors were entered individually along with +dP/dt and AOdias as third independent variables. Neither the addition of X1 (R = 0.906) or T1/2 (R = 0.926) resulted in a significant improvement in the prediction of E. CONCLUSIONS: Our observations confirm the importance of factors related to ESV as important determinants of early diastolic filling. These relations suggest that the process of early diastolic function is intimately related to systolic function.

Animals↗
PubMed1992

Transesophageal echocardiography predicts successful withdrawal of ventricular assist devices.

Transesophageal echocardiography has been found to be an effective technique for the real-time assessment of myocardial and valvular function in postoperative patients. To determine the value of transesophageal echocardiography in patients with mechanical assist devices, we performed daily, bedside transesophageal echocardiography on 16 patients with right (n = 3), left (n = 1), or biventricular assist devices (n = 12). We obtained four-chamber and short-axis views in all patients. Valvular function and the presence of left-to-right shunts were evaluated by means of color flow Doppler imaging. During the echocardiographic study ventricular assist device flow was diminished to less than 1.5 L/min, and inotropic agents (dobutamine or epinephrine) were given to assess ventricular reserve. Changes in day-to-day ventricular function were assessed in comparisons made by two observers (one unaware of the study sequence) using a semiquantitative method for wall motion analysis. The left ventricular wall motion scores in the patients successfully weaned from left or biventricular assist devices (n = 5) improved (14.2 +/- 1.6 versus 8.2 +/- 1.5, p < 0.0001). The scores did not improve in patients who remained dependent on the devices (n = 8). Two patients with only right ventricular assist devices were successfully weaned after documentation of improvement of right ventricular function by transesophageal echocardiography. Transesophageal echocardiography documented a clot compressing the heart in three patients; intracavitary thrombi were seen in two other patients. Marked hemodynamic improvement occurred after surgical decompression. In conclusion, transesophageal echocardiography is a safe, effective method for the assessment of ventricular function of patients on ventricular assist device support. In addition, it allows one to assess valvular function and the presence or absence of impaired ventricular filling.

Adult↗
PubMed1992

An embolizing lesion in a minimally diseased aorta.

A case report of a patient with an unusual source of emboli resulting in acute limb-threatening ischemia is presented. Diagnostic angiography of the lower extremity was performed, followed by thromboembolectomy, which successfully restored normal arterial flow to the threatened leg. After surgery the patient underwent transesophageal echocardiography, which failed to identify an embolic source. Because of the high degree of clinical suspicion that the primary disease process was embolic rather than thrombotic, a thorough evaluation of the arterial tree was performed, including computed tomography and aortography. A large, mobile intravascular lesion arising from a normal descending thoracic aorta was identified and successfully treated with resection and graft placement.

Angiography, Digital Subtraction↗
PubMed1992

Management of the severely atherosclerotic ascending aorta during cardiac operations. A strategy for detection and treatment.

Embolization of atheroma from the ascending aorta is a principal cause of stroke after cardiac operations. We have previously shown that intraoperative ultrasonographic scanning of the aorta rapidly, safely, and accurately identifies atheromatous disease in the ascending aorta. Intraoperative ultrasonography of the ascending aorta was performed in 500 of a consecutive series of 540 patients 50 years of age or older (mean 68 years) who underwent a variety of cardiac operations. Eighty-nine percent required bypass grafting. Sixty-eight patients (13.6% of the total) with a mean age of 72 years (range 55 to 85 years) had significant atheromatous disease in the ascending aorta and were considered to be at increased risk for embolization. Palpation identified the atheromatous disease in only 26 (38%) of these patients and underestimated its severity. A total of 168 modifications in the standard techniques for cannulation and clamping of the aorta were implemented in the 68 patients (mean 2.5 per patient) and included alterations in the sites of aortic cannulation (50 patients), aortic clamping (54 patients), attachment of the vein grafts (35 patients), and cannulation for infusion of cardioplegic solution (29 patients). Ten patients with severe diffuse atheromatous disease underwent graft replacement of the ascending aorta with hypothermic circulatory arrest without aortic clamping. Fourteen patients with symptoms or with high-grade carotid artery occlusive disease were treated by concomitant carotid endarterectomy. Thirty-day mortality for the entire group was 3.4% (17 patients). Permanent neurologic deficits occurred in five (1.0%) of the patients in the entire group but in none of the 68 patients with significant atheromatous disease in whom modifications in technique were used. One patient in the latter group had a reversible ischemic neurologic deficit. Modification of standard cannulation and clamping techniques based on ultrasonography may reduce the frequency of stroke related to atheromatous embolization.

Aged↗
PubMed1991

Two-dimensional contrast echocardiography in the detection and follow-up of congenital pulmonary arteriovenous malformations.

Pulmonary arteriovenous (A-V) malformation is frequently a manifestation of Osler-Weber-Rendu syndrome (hereditary hemorrhagic telangiectasia). We identified 14 patients (9 men and 5 women) with A-V malformation by contrast echocardiography; 10 patients with atrial right-to-left shunt served as control subjects. Agitated saline solution (10 ml) was injected through a peripheral vein during echocardiographic imaging. The delay in the appearance of microcavitations in the left atrium was measured (in number of frames) after right atrial appearance. The degree of left ventricular opacification was graded 1 to 4+ (where 4+ = intense left ventricular endocardial outline, and 1+ = minimal opacification). Results indicated patients with A-V malformation had a significant delay (p less than 0.001) in left atrial appearance of microcavitations compared with those with atrial right-to-left shunt (66 +/- 27 vs 21 +/- 7 frames, mean +/- 1 standard deviation). In the group with A-V malformation, abnormal blood gases were present in only 6 of 14 patients and chest x-ray was positive in 7. Pulmonary angiography was performed in 11 of 14 patients with positive contrast echocardiography, and all 11 had A-V malformation identified. In patients with 3 to 4+ left ventricular opacification (n = 8), large (greater than 5 mm feeding vessel) or multiple malformations were present, whereas patients with small or isolated malformation had 1 to 2+ left ventricular opacification. Balloon occlusion of malformations was performed in all 11 of these patients; repeat contrast echocardiography revealed significant diminution of right-to-left shunt in 9, and 2 required repeat embolotherapy for an additional previously undetected A-V malformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Right atrial ischemia exacerbates hemodynamic compromise associated with experimental right ventricular dysfunction.

To determine the importance of right atrial function with acute right ventricular dysfunction, sequential right ventricular and right atrial ischemia were induced in 15 dogs. Right ventricular ischemia resulted in right ventricular free wall dyskinesia, right ventricular dilation by ultrasound, elevated right ventricular filling pressure and paradoxic septal motion. There were decrements in right ventricular systolic pressure (28.9 +/- 5.5 to 25.5 +/- 4.6 mm Hg) (p less than 0.05 for these and all subsequent values) and stroke work (5.66 +/- 0.94 to 2.66 +/- 0.62 g.m/m2), resulting in reductions in left ventricular preload, systolic pressure (123 +/- 11 to 97 +/- 12 mm Hg) and stroke volume (24.2 +/- 4.3 to 19.1 +/- 5.2 ml). Right atrial contractility was augmented, as indicated by increases in peak A wave amplitude (ratio of peak A wave to mean right atrial pressure 1.22 +/- 0.02 to 1.46 +/- 0.3) and right atrial stroke work (0.11 +/- 0.02 to 0.25 +/- 0.05 g.m/m2). Right atrial ischemia depressed right atrial contraction, as indicated by decreased A wave amplitude (ratio of peak A wave to mean right atrial pressure 1.46 +/- 0.3 to 1.04 +/- 0.2) and stroke work (0.25 +/- 0.05 to 0.04 +/- 0.01 g.m/m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Left ventricular outflow obstruction resulting from insertion of mitral prostheses leaving the native leaflets intact: adverse clinical outcome in seven patients.

Left ventricular (LV) outflow obstruction may result from retaining the anterior mitral leaflet when a mitral prosthesis is inserted in the mitral anulus. We retrospectively reviewed the echocardiograms (two-dimensional Doppler and Doppler color flow imaging, or transesophageal with color flow imaging) obtained in seven patients with preoperative mitral regurgitation who had a prosthesis implanted with the native mitral leaflets left intact. Systolic anterior motion of the native anterior mitral leaflet, as seen in dynamic LV outflow tract obstruction, was observed in six of seven patients. LV fractional shortening preoperatively was less than or equal to 0.25 in all (mean 0.20 +/- 0.04) and did not significantly (p = ns) increase postoperatively (mean 0.27 +/- 0.12). Color flow imaging revealed disturbed systolic flow in the LV outflow tract in five patients, and all had systolic anterior motion of the native anterior mitral leaflet. Continuous wave Doppler detected significant systolic LV outflow tract jets in five patients averaging 4.1 +/- 0.9 m/sec. Mitral prosthetic function was normal (pressure half-time of 81 +/- 25 msec and mean gradient of 7 +/- 3 mm Hg +/- SD) in five patients. Clinical follow-up revealed that all had died, six of them within 2 months of their operation. Thus systolic anterior motion of the native anterior mitral leaflet occurs commonly after prosthetic mitral valve insertion with the native leaflets left intact. Continuous wave Doppler often demonstrates increased systolic LV outflow tract velocities consistent with dynamic LV outflow obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Regional and global myocardial circulatory and metabolic effects of isoflurane and halothane in patients with steal-prone coronary anatomy.

The use of isoflurane in patients with coronary artery disease remains controversial because of the possibility of "coronary steal". In this study, the effects of isoflurane and halothane on global and regional myocardial blood flow and metabolism were compared, and the relationship between steal-induced myocardial ischemia and the administered volatile anesthetic was investigated in 40 patients with steal-prone coronary anatomy undergoing elective coronary artery bypass operations. The patients were randomly assigned to receive either isoflurane or halothane (0.5 MAC inspired concentration) immediately after induction with fentanyl (50 micrograms/kg). Hemodynamic measurements and blood samples were obtained at preinduction, postintubation, preincision, poststernotomy, at 60 min after beginning isoflurane or halothane, and precannulation (a total of 238 study events). Throughout the study, heart rate was kept constant by atrial pacing at approximately postintubation values while arterial pressure was maintained within 10% of postintubation values with fluid administration or phenylephrine infusion. Overall, systemic hemodynamic changes observed during the study were similar in the two groups. Myocardial ischemic episodes were defined as a new electrocardiographic ST-segment shift of greater than or equal to 0.1 mV, new echocardiographic regional wall motion abnormalities (RWMA) and/or myocardial lactate production (MLP). A total of 18 new ischemic episodes were detected in 15 patients (7 episodes during isoflurane in 7 patients and 11 during halothane in 8 patients). Ten (56%) episodes were related to acute hemodynamic abnormalities, whereas 8 (44%) were random and unrelated to changes. Seven episodes were detected by echocardiography (38%), 6 by MLP (33%) and 1 by ECG (6%) only, whereas concomitant echocardiographic abnormalities and MLP were observed during 2 episodes (11%), echocardiographic and ECG during 1 (6%), and ECG and MLP during 1 other (6%). Ratios of regional to global coronary venous flow, coronary vascular resistance, myocardial oxygen content, and lactate extraction, along with hemodynamic data obtained during these episodes, do not support coronary steal for the development of myocardial ischemia. We conclude that in patients with steal-prone coronary anatomy anesthetized with fentanyl, neither isoflurane nor halothane administered at concentrations used in the current study is likely to cause myocardial ischemia by the coronary steal mechanism.

Adult↗
PubMed1991

Measuring physical activity with a single question.

Using 1,004 subjects enrolled in a worksite health promotion program, this report evaluated the validity of a single question about participation in regular exercise. Measured at baseline, this one question had a significant age-adjusted association with body mass index (p less than 0.0001 in women and p = 0.001 in men), HDL cholesterol (p less than 0.0001 in women), and oxygen capacity (p = 0.0007 in women and p = 0.002 in men). Thus, one self-reported question can provide useful information about who is and who is not participating in regular exercise. The potential validity of a single exercise question is particularly relevant in complex epidemiologic studies where lengthy questionnaires highlight the importance of brief instruments.

Adult↗
PubMed1991

Intraoperative ultrasonographic evaluation of the ascending aorta in 100 consecutive patients undergoing cardiac surgery.

Dislodgement of atheromatous plaque from the ascending aorta following manipulation is one of the principal causes of stroke following cardiac surgery. To define clinical correlates that predict the presence of severe atherosclerosis, we performed ultrasonographic evaluation of the ascending aorta at the time of cardiac surgery in 100 consecutive patients. The ascending aorta was divided into three equal segments for analysis, and the severity of atherosclerosis was determined as mild when intimal thickening (less than 3 mm) was localized to one segment, moderate when intimal thickening (greater than 3 mm) was present in one or two segments, and severe when intimal thickening (greater than 3 mm) was present throughout the entire circumference in all three segments. Thirty-eight percent of the studies were normal, mild atherosclerosis was present in 33%, moderate atherosclerosis in 19%, and severe atherosclerosis in 10% of the patients. Palpation of the ascending aorta to detect atherosclerosis significantly underestimated the presence (p less than 0.001) and severity (p less than 0.001) of atherosclerosis when compared with ultrasonography. Age, carotid artery disease, diabetes, gender, smoking, and hypertension were evaluated for their ability to discriminate between normal and severely atherosclerotic aortas. Stepwise logistic regression analysis showed age (p less than 0.02) and diabetes (p less than 0.04) to be significant independent predictors of the presence of severe atherosclerosis in the ascending aorta. Based on the ultrasonographic findings, the operative procedure was altered to reduce the risk of embolization in 17% of the patients. We conclude that high-resolution images of the ascending aorta for identification of atherosclerosis can be obtained by ultrasonography.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗