Biomedical subjects

A Waaler

Publications and source records attributed to A Waaler.

12 recordsLinked to original sources

PubMed1996

The influence of Albunex on the pulmonary circulation in patients with pulmonary hypertension or left heart failure.

To determine the safety of the ultrasound contrast agent Albunex, its influence on right and left heart haemodynamics in patients with pulmonary artery hypertension or left heart failure was assessed after intravenous injection. Patients with a left ventricular ejection fraction smaller than 40% or a systolic pulmonary artery pressure greater than 40 mmHg received 0.08 and 0.22 ml.kg-1 Albunex and 10 ml albumin in random order during right heart catheterization and transthoracic echocardiography. Right atrial, systolic and diastolic pulmonary artery and capillary wedge pressures were measured at 3 min and 5 min and cardiac output at 5 min after the intravenous injection of Albunex and control. The mean differences of pre- and postinjection values and their confidence intervals were tabulated and significance was anticipated if the confidence interval did not include 0. Significant changes to pre-injection values could be observed in diastolic pulmonary artery pressure 5 min after the injection of albumin and 0.08 ml.kg-1 Albunex, and in right atrial pressure 5 min after the injection of 0.22 ml.kg-1 Albunex only. Since intermediate opacification of the left ventricle was seen in only four patients with 0.22 ml.kg-1 Albunex, in the patients studied higher doses of Albunex and their safety need to be assessed.

Albumins↗

PubMed1993

Digital radiofrequency echocardiography in the detection of myocardial contrast following intravenous administration of Albunex.

Conventional contrast echo techniques have proved inadequate for the detection of myocardial perfusion using intravenously injected echo contrast agents because of the limitations and relative insensitivity of standard echocardiographic equipment. In order to avoid these problems, we have obtained pure digital radiofrequency ultrasound data from the left ventricle and myocardium during i.v. contrast myocardial perfusion echo studies. In 30 patients, following coronary arteriography, i.v. injections of the echo contrast agent Albunex (sonicated human serum albumin) in two doses of 0.08 and 0.22 ml.kg-1 were administered during digital radiofrequency echocardiography sampling of data from the myocardium and left ventricular cavity. Analysis of mean integrated backscatter (MIB, a measure of the total ultrasound energy) was performed before, during and after Albunex injection. The data were also analysed for a shift in frequency spectrum which could be caused by resonance of the Albunex contrast microspheres in the heart, a phenomenon which has been previously demonstrated in vitro. Digital radiofrequency ultrasound data were successfully obtained and analysed in 23 patients. In 31 segments where reasonable resting perfusion was expected, there was a significant increase in MIB from 0.644 to 1.245, P < 0.001 and time intensity curves could be constructed showing wash-in and wash-out of contrast from the myocardium. In 10 segments supplied by significantly diseased vessels, MIB intensity increased from 1.044 to 1.874, P = 0.054. In myocardial segments supplied by non-diseased vessels, microsphere resonance also caused a drop in mean frequency of 140 KHz, P < 0.001, and permitted similar temporal analysis of myocardial perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Intracoronary albunex. Its effects on left ventricular hemodynamics, function, and coronary sinus flow in humans.

BACKGROUND: Albunex is a recently developed ultrasonic contrast agent made from sonicated human serum albumin. The effects on left ventricular hemodynamics, function, and coronary sinus flow of intracoronary Albunex in humans have not been reported. METHODS AND RESULTS: Eighteen patients with known or suspected coronary artery disease were examined at the time of coronary arteriography with simultaneous two-dimensional echocardiography and left ventricular catheter-tip manometry. Intracoronary injections of Albunex into the left main coronary artery were performed, as were injections of 5% human serum albumin and iohexol, a widely used angiographic contrast agent. Mean coronary sinus flow was determined before and after injections of iohexol and 2 mL of Albunex. Injection of 1 mL of Albunex induced no changes in any of the measured hemodynamic parameters (heart rate, peak left ventricular [LV] systolic pressure, LV end-diastolic pressure, positive or negative LV dP/dt, or time constant of relaxation) or echocardiographic determinants of LV function (regional wall motion and global ejection fraction). Injection of 2 mL or more of Albunex caused small, transient (less than 30 seconds) changes in measures of isovolumic relaxation (negative LV dP/dt; 95% confidence interval: mean, -2.41 [-4.3, -0.52] and tau 1; confidence interval mean, 3.52; [1.48, 5.58]) but not in functional measures. Intracoronary injection of 5% human serum albumin had no effect. Iohexol induced small but significant changes in both systolic and diastolic parameters, which lasted beyond 30 seconds after injection. Mean coronary sinus blood flow increased. CONCLUSIONS: The effects of Albunex on hemodynamics, left ventricular function, and coronary sinus blood flow compare favorably with iohexol. Albunex can be considered to be an essentially inert contrast agent if used in patients with stable coronary artery disease.

Adolescent↗

PubMed1992

Iopentol in urography. A clinical comparison between iopentol and metrizoate including delayed reactions.

A double-blind comparative study of the nonionic contrast medium iopentol and the ionic contrast medium metrizoate for urography was carried out in 200 adult outpatients. Significantly less discomfort and other side effects were observed following iopentol than following metrizoate. No serious adverse reactions and no clinically significant alterations in heart rate or blood pressure were observed. A questionnaire was used to record delayed symptoms, from 30 min after contrast medium injection and for one week. The response rate was 92% and delayed adverse events were reported by 45%. The incidence of delayed reactions was significantly lower following iopentol than following metrizoate, i.e., delayed arm pain, fatigue, headache, diarrhea, nasal congestion, and rash. Delayed arm pain was probably due to contrast medium induced thrombosis in 1% following iopentol and in 8% following metrizoate. Most other symptoms were probably related to a combination of nocebo effect and coincidentally occurring symptoms. The urograms with both media were of similar high quality. Iopentol was found a suitable contrast medium for urography.

Adult↗

PubMed1990

Intravenous urography with a new non-ionic contrast media in a clinical phase III study: iopentol vs iohexol.

The safety and diagnostic efficacy of iopentol 300 mg I/ml were compared with iohexol 300 mg I/ml in 300 patients submitted for urography. The study was carried out as a double-blind, randomised parallel study where 149 patients received iopentol and 150 patients iohexol. There were no significant differences between the patients receiving the two contrast media with regard to demographic parameters, rate of injection or total dose of injected contrast media. No changes in blood pressure and no clinically important changes in heart rate were detected in the two groups. No serious adverse effects occurred. Seven patients (5%) in the iohexol and 12 patients (8%) in the iopentol group experienced adverse effects other than a sensation of warmth. Fourteen iohexol patients (9%) and 18 iopentol patients (12%) experienced warmth related to the contrast injection. Excellent films were obtained in most patients and no difference in diagnostic quality between iopentol and iohexol was observed.

Adult↗

PubMed1990

Elimination of iohexol, a low osmolar nonionic contrast medium, by hemodialysis in patients with chronic renal failure.

The dialyzability of iohexol was examined in patients with chronic renal failure on long-term hemodialysis treatment. Eight patients had iohexol (Omnipaque 240 or 350 mg I/ml) injected in doses between 98 and 1,493 mg I/kg body weight (BW) 25 h (mean time) before start of hemodialysis. Dialysance of iohexol was 81 +/- 15 ml/min (mean +/- SD) compared to 120 +/- 16.8 ml/min for creatinine. Elimination half-life for iohexol during hemodialysis was 3.9 +/- 1.1 h while plasma clearance was 64 +/- 17 ml/min. The distribution volume calculated (0.25 +/- 0.05 liters/kg BW) confirms previous observations with distribution in the extracellular fluid only. Before the start of hemodialysis 36 +/- 28% of the dose injected was eliminated, indicating some extrarenal elimination. After 4 h of hemodialysis 72 +/- 11% of the dose was removed.

Adult↗

PubMed1990

Renal effects of the non-ionic contrast medium iopentol after intravenous injection in healthy volunteers.

Renal effects of the new non-ionic contrast medium iopentol in increasing doses were assessed and compared with the effects of physiologic saline. Twenty-four healthy male volunteers, allocated to three dose groups, were given iopentol intravenously in doses of 0.3, 0.6, and 1.2 g I/kg body weight, respectively. The highest dose group was also given physiologic saline separately as a control. The diuresis increased in all groups, most in the highest dose group, and with a concomitant fall of urine osmolality and increase in osmolar clearance. A slight decrease of serum osmolality, creatinine and urea occurred at 3 hours due to hemodilution. The glomerular filtration rate was unaffected by iopentol. The urinary excretion of albumin and beta 2-microglobulin was unchanged. However, urinary N-acetyl-beta-glucosaminidase and alkaline phosphatase increased significantly, most in the highest dose group. All changes were reversible.

Acetylglucosaminidase↗

PubMed1989

Safety and toleration of the non-ionic contrast medium iopentol. An intravenous phase I trial.

The safety and toleration of iopentol, a new non-ionic contrast medium for intravascular use, were evaluated. In the intravenous phase I study, 24 volunteers were allocated to 3 dose groups corresponding to 0.3, 0.6 or 1.2 g I/kg body weight, respectively. Injection of saline was used as control in the highest dose group. Adverse events, hemodynamic parameters, and clinical chemical parameters in the blood and urine were recorded. No severe or unexpected adverse events occurred. All findings were transient and included a sensation of warmth, a small increase in heart rate, a dilution effect on blood parameters, and enzymuria. The deviations in clinical chemical parameters fell mostly within reference ranges and were clinically insignificant. Thus, iopentol may safely be advanced to clinical trials in patients for comparative studies.

Adult↗

PubMed1988

Clinical trial program for iopentol. A new nonionic ratio 3.0 contrast medium with emphasis on clinical phases I and II.

Iopentol is a new nonionic, water-soluble ratio 3.0 roentgen contrast medium (CM) for vascular use. The aim is to present the vascular clinical trial program for iopentol and to report the findings from the clinical phases I and II. The clinical program started with an intravenous (IV) safety and pharmacokinetic phase I trial (24 volunteers) and continued with six open, noncomparative phase II trials (61 patients) for studying cardiovascular and arterial tolerance (two trials in cardioangiography), venous tolerance (two trials in IV computed tomography [CT] enhancement), and cerebral and arterial tolerance (2 trials in cerebral arteriography). One volunteer in the phase I trial was excluded because of a vasovagal reaction following saline injection, and four patients were protocol deviators in cardioangiography. Mainly renal glomerular filtration of unmetabolized iopentol, close to 100% recovered after 24 hours in the urine, was found in the phase I study. No unexpected or severe contrast-induced reactions were encountered in phases I and II. Good diagnostic efficiency was obtained in phase II. As also expected, iopentol seemed to be well-tolerated. However, its relative efficiency and tolerance profile can only be documented from the ongoing comparative phase III trials.

Contrast Media↗

PubMed1987

Pharmacokinetics of iopentol in healthy volunteers.

Iopentol is a new non-ionic contrast medium. In order to study the pharmacokinetic properties, iopentol 350 mg I/ml was administered intravenously to healthy male volunteers at 3 dose levels (0.3, 0.6 and 1.2 g I/kg body weight). To evaluate renal excretion all subjects were given chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA) additionally to iopentol. The highest dose level group also received saline and 51Cr-EDTA about 3 weeks prior to iopentol. Serum, urine and faeces were sampled at different time intervals. Unmetabolized iopentol was excreted almost entirely in urine during the first 24 hours by means of glomerular filtration. A small fraction (2%) of the dose was excreted in faeces. No dose dependent pharmacokinetics was observed up to doses of 1.2 g I/kg body weight. The pharmacokinetic properties of iopentol make it a well suited contrast medium for vascular use.

Adult↗

PubMedDate not supplied

Publications on clinical trials with X-ray contrast media: differences in quality between journals and decades.

The objective of the present study was to investigate the quality of clinical trial publications on X-ray contrast media by use of a simple criteria list with 11 items. The publication quality in the 1960s, 1970s and 1980s and in five radiological journals was compared. One hundred and three articles retrieved from the literature and published in Br J Radiol (British), Acta Radiol (Scandinavian), Radiology (American), RöFo (German) and in Ann Radiol (French) were finally included. The adapted method seemed to be suitable for roughly assessing the quality of contrast medium publications. The present reporting standard has increased considerably since the 1960s, however a higher standard is still needed. Although the limited material gathered in our investigation does not allow unequivocal statements, the results indicate that the reporting standard of the 1980s in the selected American, British and Scandinavian radiological journals was somewhat better than in the German journal and better than in the French journal. Use of the present or other assessment methods is one tool to improve the reporting standard.

Clinical Trials as Topic↗

PubMedDate not supplied

Left ventricular volume determination using Albunex.

The aim of this study was to assess the ability of intravenous injection of Albunex to improve left ventricular volume determination in patients with various cardiac diseases. It is conceivable that the intravenous injection of microbubbles could improve echocardiographic left ventricular border delineation leading to improved interobserver variability. Echocardiograms were obtained during simultaneous intravenous injection of 0.08 and 0.12 ml/kg Albunex (four-chamber view). Within 6 hours after the recording of the contrast echocardiograms routine left heart angiography was performed. Volumes were measured using the slice method in native and contrast echocardiograms as well as in the angiograms by two independent investigators. The mean differences of angiographic-native echocardiographic and angiographic-contrast echocardiographic volumes (ml) as well as the calculated ejection fraction and their confidence intervals were tabulated and significance was anticipated if the confidence interval did not include zero. Significant changes to angiographic values could be observed concerning end-diastolic, echocardiographic, and contrast echocardiographic volumes at end diastole and end systole, while ejection fractions were similar. Differences between observers were significantly smaller in the contrast echocardiographic images than in the native echocardiographic images. Albunex led to a significantly decreased interobserver variability.

Adult↗