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Biomedical subjects

H Baumgartner

Publications and source records attributed to H Baumgartner.

At least 55 records · Page 3Linked to original sources
PubMed1996

Ibuprofen and diclofenac sodium in the treatment of osteoarthritis: a comparative trial of two once-daily sustained-release NSAID formulations.

An investigator-blind, parallel-group, multicentre study was undertaken to compare the efficacy and tolerability of once-daily, sustained-release (s-r) ibuprofen and diclofenac sodium in patients (mean age 59.8 years) suffering from painful osteoarthritis affecting chiefly the knee and/or hip. Patients attending eight Swiss centres received either two s-r tablets of ibuprofen (daily dose 1600 mg; n = 30) or a single s-r diclofenac 100 mg tablet (n = 31) each evening for 21 days. Clinical assessments were performed prior to initiating therapy and after 7 and 21 days of treatment. Both treatments were efficacious, but statistically significant differences in favour of s-r ibuprofen were observed for the principal measure of efficacy, the investigator's assessment of the overall change in clinical condition; by Day 21, 37% of ibuprofen-treated patients vs 10% of diclofenac-treated patients were 'much improved' (p = 0.04). Patients' assessments of the efficacy of their treatment also favoured s-r ibuprofen at Day 7 for the relief of night pain (p = 0.048), at Day 21 for alleviation of day pain (p = 0.006) and for the ability to carry out normal activities (p = 0.01), and at both Days 7 and 21 for quality of sleep (p = 0.04 and 0.03, respectively). The patients' overall opinion of treatment was also significantly in favour of s-r ibuprofen, which was rated 'good or excellent' by 80% (24/30), compared with only 38% of patients (11/29) receiving s-r diclofenac sodium (p = 0.002). Two patients (6%) receiving s-r diclofenac sodium ceased treatment owing to dizziness and severe diarrhoea, respectively; there were no withdrawals in the ibuprofen-treated group. Ten (32%) patients in the s-r diclofenac group reported a total of 12 adverse events (mostly gastrointestinal in nature), compared with three (10%) patients in the s-r ibuprofen group who reported only three events (abdominal pain, insomnia and constipation). In conclusion, although both NSAID treatments improved the clinical condition of patients with painful osteoarthritis, statistically significant differences in favour of once-daily s-r ibuprofen (1600 mg) were demonstrated in terms of efficacy, indicating a potential therapeutic advantage for this formulation. Ibuprofen was also better tolerated than diclofenac sodium (100 mg/day), the latter being associated with gastrointestinal side effects in a significant proportion of patients. Sustained-release ibuprofen (Brufen Retard) thus represents an important addition to the available therapeutic armamentarium of once-daily NSAID formulations.

Activities of Daily Living↗
PubMed1996

Closure of ruptured coronary sinus by a pericardial patch.

We report on a case of coronary sinus rupture that happened during placement of a cardioplegia balloon catheter and its subsequent repair. First, the defect was oversewn, however, not successfully. Under cardiopulmonary bypass and cardioplegic arrest, a pericardial patch was used to reconstruct the coronary sinus. Six months after the operation, blood drained during diastole into the right atrium but the flow was partially reversed during systole.

Adult↗
PubMed1995

Estimation of coronary flow reserve by transesophageal coronary sinus Doppler measurements in patients with syndrome X and patients with significant left coronary artery disease.

OBJECTIVES: This study sought to determine the feasibility of coronary sinus flow velocity analysis by transesophageal Doppler echocardiography for estimation of coronary flow reserve in patients with syndrome X and patients with coronary artery disease. BACKGROUND: Coronary flow reserve provides useful information in patients with coronary artery disease and patients with syndrome X. Current methods of measuring coronary flow reserve are invasive or require extensive laboratory equipment, or both. Transesophageal Doppler recordings of coronary sinus flow velocity before and after vasodilator application may allow noninvasive determination of coronary flow reserve. METHODS: We obtained coronary sinus flow velocity recordings before and after dipyridamole administration (0.6 mg/kg body weight per 5 min) in 9 patients with syndrome X, 14 with significant left coronary artery disease and 22 age-matched control patients. We used the formula anterograde minus retrograde flow velocity time integral times heart rate as an index of coronary sinus flow. Coronary flow reserve was calculated by dividing coronary sinus flow variables after dipyridamole administration by the respective baseline values. RESULTS: Technically adequate recordings were obtained in 44 (98%) of 45 patients. Compared with that in the control group (2.78 +/- 0.95 [mean +/- SD]), coronary flow reserve was significantly lower in patients with syndrome X (1.21 +/- 0.23, p < or = 0.001) as well as in those with coronary artery disease (1.47 +/- 0.7, p < or = 0.001). Using a cutoff coronary flow reserve value of 1.8, sensitivity, specificity and overall predictive value of coronary flow reserve determinations were, respectively, 100%, 91% and 94% for syndrome X and 86%, 91% and 89% for coronary artery disease. CONCLUSIONS: Coronary flow reserve calculation by transesophageal coronary sinus flow velocity recordings is feasible in a large proportion of patients and might be useful for the noninvasive evaluation of patients with syndrome X and patients with severe left coronary artery disease.

Blood Flow Velocity↗
PubMed1995

Partial papillary muscle rupture complicating acute myocardial infarction. diagnosis by multiplane transoesophageal echocardiography.

Papillary muscle rupture is a rare but generally fatal mechanical complication of acute myocardial infarction. In contrast to complete papillary muscle rupture, echocardiographic recognition of partial papillary muscle rupture has rarely been reported and seems to be more challenging. We describe a patient with partial papillary muscle rupture that could only be diagnosed by multiplane transoesophageal echocardiography, whereas transthoracic echocardiography and single plane transesophageal echocardiography showed only posterior mitral leaflet prolapse.

Echocardiography, Transesophageal↗
PubMed1994

[Primary angioplasty in acute myocardial infarct].

We report our experience with primary angioplasty (PPTCA) in acute myocardial infarction performed without prior thrombolytic therapy. Between January 1991 and April 1993, 44 patients underwent PPTCA. Duration of symptoms was 163 +/ 106 min; age range of patients was 30 to 89 years (mean 60.6 +/- 13.5 years). Twelve patients presented with cardiogenic shock (27%), 17 patients (39%) had at least one relative contraindication for thrombolysis. Primary success rate was 98%. No stroke or major bleeding was observed. Reocclusion occurred in two patients, whereby this complication was silent in one of the cases. Significant residual stenosis remained in two additional patients. Three patients (7%) underwent elective bypass surgery (ACBG). Overall two-week mortality was 9%, and only 3% in the subgroup of patients without cardiogenic shock. Complete follow-up (FU) exceeding four months is now available in 36 patients (mean FU 13.7 +/- 7.3 months). During the FU period three patients had ACBG and five patients had PTCA. Thus, seven of 36 patients (19%) needed an additional procedure. Three patients had died, all of them were older than 70 years and initially presented with cardiogenic shock. Overall survival (in hospital and FU) was 84% (97% when patients with cardiogenic shock were excluded). Long-term survival (in hospital and FU) of the twelve patients initially presenting with cardiogenic shock was 50%. In conclusion, PPTCA is a promising therapeutic option in patients with acute myocardial infarction, especially when thrombolysis is contraindicated or when cardiogenic shock is present. It appears to be feasible even in centers with only one available catheterization unit.

Adult↗
PubMed1993

Effect of stenosis geometry on the Doppler-catheter gradient relation in vitro: a manifestation of pressure recovery.

OBJECTIVES: This study investigated the effect of stenosis geometry on the Doppler-catheter gradient relation. BACKGROUND: Although gradient estimation by Doppler ultrasound has been shown to be accurate in various clinical and in vitro settings, there have also been reports of substantial discrepancies between Doppler and catheter gradients. These conflicting results may be due to differences in geometry and hemodynamic characteristics of flow obstructions. METHODS: Stenoses of various geometry were simultaneously studied with continuous wave Doppler and catheter technique in a well controlled pulsatile flow model. RESULTS: Doppler and catheter gradients correlated very well regardless of stenosis geometry and site of distal catheter measurement (r = 0.98 to 0.99, SEE = 1.8 to 5.3 mm Hg). When the catheter was pulled back through the stenosis, the highest gradients were found in or close to the stenosis. When these catheter gradients were compared with Doppler gradients, the agreement between the two techniques was excellent regardless of stenosis geometry (slope 0.97; mean difference 0.6 +/- 2.0 mm Hg). However, when distal pressures were measured 10 cm downstream from the stenotic segment, the slope of the regression line, and therefore the agreement between Doppler and catheter gradients, differed for the different stenosis types (slopes from 0.98 to 1.69). In stenoses with abrupt narrowing and abrupt expansion, agreement was acceptable. Doppler gradients were only slightly greater than catheter gradients (mean difference 4.5 +/- 5.2 mm Hg). In stenoses with a gradually tapering inlet and outlet, the Doppler-catheter gradient relation was dependent on the outflow angle. Good agreement was found for an angle of 60 degrees (mean difference 0.6 +/- 1.8 mm Hg). In stenoses with a 40 degrees outflow angle, Doppler gradients exceeded the catheter gradients by 13% on average; for stenoses with a 20 degrees outflow angle, Doppler gradients exceeded catheter gradients by 46 +/- 11.4%, with differences as great as 65 mm Hg. These results were identical for stenoses gradually tapering outward to the distal tubing diameter and those with abrupt expansion after 2 cm of gradual expansion. The results were also not affected by changing the inflow angle from 20 degrees to 60 degrees. However, an abrupt narrowing instead of a tapering inlet significantly altered the Doppler-catheter gradient relation (p < 0.001); Doppler gradients exceeded the catheter gradients by 34 +/- 10% for this stenosis type. CONCLUSIONS: Doppler gradients accurately reflect the highest gradients across flow obstructions that occur in the vena contracta. However, these gradients may be significantly greater than catheter gradients that are measured farther downstream, as is usually the case in clinical catheterization studies. These discrepancies are due to pressure recovery. The magnitude of pressure recovery is highly dependent on the stenosis geometry, which therefore significantly affects the Doppler-catheter gradient relation. It is the outflow geometry that predominantly influences this relation, but the shape of the inlet may affect the results as well. Although pressure recovery occurs even in stenoses with abrupt narrowing and abrupt expansion, the phenomenon is most likely to become clinically relevant in stenoses with a gradually tapering inlet and outlet with an outflow angle < or = 20 degrees.

Blood Pressure↗
PubMed1993

Effect of prosthetic valve malfunction on the Doppler-catheter gradient relation for bileaflet aortic valve prostheses.

BACKGROUND: Considerable discrepancies between Doppler and catheter gradients caused by localized gradients and pressure recovery have been reported for normal bileaflet aortic valve prostheses. METHODS AND RESULTS: To examine whether this Doppler-catheter gradient relation is affected by prosthetic valve malfunction, a 19-mm CarboMedics aortic valve was simultaneously studied with continuous-wave Doppler and catheter technique in normal function and in various states of malfunction ranging from slightly restricted opening to total occlusion of one leaflet. For each functional status, peak and mean gradients were measured at eight different flow rates (cardiac output, 2.0-6.0 L/min). Excellent correlation between Doppler and catheter gradients was found regardless of the valve function (r = 0.99, SEE = 1.0-3.3 mm Hg). However, the relation between Doppler and catheter gradient was highly dependent on the function of the valve as shown by a variation of slopes from 1.08 to 2.08. For the normally functioning valve (angle between flow axis and leaflet 5 degrees), peak and mean Doppler gradients were approximately twice the catheter gradients (slope, 2.08 and 2.03 for peak and mean gradients, respectively). Slightly restricted opening of one leaflet (22 degrees) significantly altered the Doppler-catheter gradient relation, and slopes decreased to 1.69 (p < 0.01) and 1.52 (p < 0.001) for peak and mean gradients, respectively. The differences between Doppler and catheter gradients significantly decreased with further restriction of valve opening, and slopes ranged from 1.25 to 1.41 for angles between 34 degrees and 52 degrees. When one leaflet was totally occluded, the slope finally dropped to 1.08 for both peak and mean gradients, and Doppler gradients were only slightly greater than catheter gradients. Gradients increased with malfunction of the valve caused by reduction of the effective orifice area. However, the increase of Doppler gradients was considerably smaller than the increase of simultaneous catheter gradients. CONCLUSIONS: The discrepancies between Doppler and catheter gradients that have been reported for normally functioning bileaflet aortic valve prostheses may be reduced or even disappear in patients with malfunctioning valves. Furthermore, the increase of Doppler gradients caused by malfunction of the valve may underestimate the true hemodynamic changes.

Aortic Valve↗
PubMed1993

[Clinical aspects of spinal stenosis].

Spinal stenosis is a common problem in the elderly population. Thanks to better knowledge it is being diagnosed more frequently and in many cases successfully treated by surgery. Clinically, patients with a lumbogluteal and in later stages bilateral sciatic pain syndrome can be differentiated from patients with monoradicular pain. Typically, the posture deteriorates with walking distance. Spinal stenosis must be differentiated from peripheral vascular disorders and compressive disc herniation. The possibilities of conservative therapy are limited and their effect is lasting only in mild cases.

Adult↗
PubMed1992

Electrophysiological findings in a case of severe intrathecal baclofen overdose.

Multimodality evoked potentials were examined in a case of serious accidental intrathecal baclofen overdose in a patient who suffered from severe spasticity due to a traumatic brain lesion. Electrophysiological findings during, before and after the intoxication were compared. Transcranial electrical stimulation up to 750 V did not evoke any responses in thenar muscles on the first day of intoxication. An improvement to normal values was observed within 3 days, paralleled by an amelioration of the patient's clinical condition. Cervical electrical stimulation was largely unaffected by baclofen. Median nerve somatosensory and brain-stem acoustic evoked potentials revealed few or no differences during intoxication compared to pre- and post-intoxication responses.

Adolescent↗
PubMed1992

Effect of prosthetic aortic valve design on the Doppler-catheter gradient correlation: an in vitro study of normal St. Jude, Medtronic-Hall, Starr-Edwards and Hancock valves.

To evaluate the normal range of Doppler-derived velocities and gradients, their relation to direct flow measurements and the importance of prosthetic valve design on the relation between Doppler and catheter-derived gradients, five sizes of normal St. Jude bileaflet, Medtronic-Hall tilting disc, Starr-Edwards caged ball and Hancock bioprosthetic aortic valves were studied with use of a pulsatile flow model. A strong linear correlation between peak velocity and peak flow, and mean velocity and mean flow, was found in all four valve types (r = 0.96 to 0.99). In small St. Jude and Hancock valves, Doppler velocities and corresponding gradients increased dramatically with increasing flow, resulting in velocities and gradients as high as 4.7 m/s and 89 mm Hg, respectively. The ratio of velocity across the valve to velocity in front of the valve (velocity ratio) was independent of flow in all St. Jude, Medtronic-Hall, Starr-Edwards and Hancock valves when the two lowest flow rates were excluded for Hancock valves. Although Doppler peak and mean gradients correlated well with catheter peak and mean gradients in all four valve types, the actual agreement between the two techniques was acceptable only in Hancock and Medtronic-Hall valves. For St. Jude and Starr-Edwards valves, Doppler gradients significantly and consistently exceeded catheter gradients with differences as great as 44 mm Hg. Thus, Doppler velocities and gradients across normal prosthetic heart valves are highly flow dependent. However, the velocity ratio is independent of flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1992

Color Doppler regurgitant characteristics of normal mechanical mitral valve prostheses in vitro.

BACKGROUND: To evaluate normal regurgitant characteristics of St. Jude (SJ) and Medtronic-Hall (MH) mitral valves, four sizes (25-31 mm) of each were studied in a pulsatile flow model. METHODS AND RESULTS: Regurgitant flow was measured by flowmeter at left ventricular pressures of 80, 130, and 180 mm Hg. Peak regurgitant flow rates ranged from 6.2 to 12.7 cm3/sec in SJ valves and from 7.9 to 17.5 cm3/sec in MH valves. Regurgitant orifice areas calculated from the Doppler continuity equation ranged from 1.6 to 2.0 mm2 in SJ valves and from 2.2 to 2.9 mm2 in MH valves. Regurgitant volumes across the closed valve at a left ventricular pressure of 130 mm Hg were normalized to an ejection time of 280 msec and ranged from 1.5 to 1.9 cm3 in SJ valves and from 2.1 to 2.8 cm3 in MH valves. Jets were imaged by color Doppler in six rotational planes, and jet size and morphology were compared with those of regurgitant jets from circular orifices with sizes comparable to the calculated prosthetic valve regurgitant orifices (1.1-3.1 mm2). SJ valves showed two converging jets from the pivot points, one central jet, and a variable number of peripheral jets. The mean color jet area derived from the six image planes ranged from 1.6 to 5.3 cm2. Aliasing occurred only close to the valve (maximal distance 0.5-2.0 cm). MH valves showed a large central jet with a maximal length of aliased flow between 2.0 and 5.5 cm. Depending on valve size, driving pressure, and image plane, one or two small peripheral jets were found. These jets did not show aliasing in any case. The mean color jet area ranged from 5.1 to 11.0 cm2. Jets originating from circular orifices of comparable size showed jet areas from 5.5 to 13.9 cm2 and aliasing distances from 3.3 to 7.3 cm. At similar regurgitant orifice areas, driving pressures, and regurgitant flows, the measured color areas and aliasing distances were smallest in SJ valves, larger in MH valves, and largest in simple circular orifices. CONCLUSIONS: Large, complex regurgitant jets can be found in normal closed SJ and MH valves by color Doppler, although regurgitant flow volume is minimal. Jet size and velocity distribution differs markedly between SJ valves, MH valves, and circular orifices, even with comparable driving pressure, regurgitant orifice area, and regurgitant volume. The characteristic patterns of normal regurgitation must be recognized to avoid incorrect diagnoses of pathological regurgitation in SJ and MH prosthetic valves. MH valves should not be removed solely on the basis of a central regurgitant jet with a long aliasing distance. Peripheral jets in MH valves and all jets in SJ valves should be considered normal as long as no or only minimal aliasing is present. In contrast, peripheral jets with significant aliasing may represent strong evidence of pathological regurgitation.

Blood Flow Velocity↗
PubMed1992

Doppler assessment of prosthetic valve orifice area. An in vitro study.

BACKGROUND: Although Doppler echocardiography has been shown to be accurate in assessing stenotic orifice areas in native valves, its accuracy in evaluating the prosthetic valve orifice area remains undetermined. METHODS AND RESULTS: Doppler-estimated valve areas were studied for their agreement with catheter-derived Gorlin effective orifice areas and their flow dependence in five sizes (19/20-27 mm) of St. Jude, Medtronic-Hall, and Hancock aortic valves using a pulsatile flow model. Doppler areas were calculated three ways: using the standard continuity equation; using its simplified modification (peak flow/peak velocity); and using the Gorlin equation with Doppler pressure gradients. The results were compared with Gorlin effective orifice areas derived from direct flow and catheter pressure measurements. Excellent correlation between Gorlin effective orifice areas and the three Doppler approaches was found in all three valve types (r = 0.93-0.99, SEE = 0.07-0.11 cm2). In Medtronic-Hall and Hancock valves, there was only slight underestimation by Doppler (mean difference, 0.003-0.25 cm2). In St. Jude valves, however, all three Doppler methods significantly underestimated effective orifice areas derived from direct flow and pressure measurements (mean difference, 0.40-0.57 cm2) with differences as great as 1.6 cm2. In general, the modified continuity equation calculated the largest Doppler areas. When orifice areas were calculated from the valve geometry using the area determined from the inner valve diameter reduced by the projected area of the opened leaflets, Gorlin effective orifice areas were much closer to the geometric orifice areas than Doppler areas (mean difference, 0.40 +/- 0.31 versus 1.04 +/- 0.20 cm2). In St. Jude and Medtronic-Hall valves, areas calculated by either technique did not show a consistent or clinically significant flow dependence. In Hancock valves, however, areas calculated by both the continuity equation and the Gorlin equation decreased significantly (p less than 0.001) with low flow rates. CONCLUSIONS: Doppler echocardiography using either the continuity equation or Gorlin formula allows in vitro calculation of Medtronic-Hall and Hancock effective valve orifice areas but underestimates valve areas in St. Jude valves. This phenomenon is due to localized high velocities in St. Jude valves, which do not reflect the mean velocity distribution across the orifice. Valve areas are flow independent in St. Jude and Medtronic-Hall prostheses but decrease significantly with low flow in Hancock valves, suggesting that bioprosthetic leaflets may not open fully at low flow rates.

Aortic Valve↗
PubMed1992

Capillary versus arterial plasma catecholamines as markers for sympatho-adrenal activity in infants.

In this study, we investigated whether capillary plasma catecholamines can be used as a suitable substitute for arterial catecholamines. Analysis was done radioenzymatically. Catecholamine concentrations were not different in arterial and simultaneously collected "arterialized" (warmed foot) capillary plasma obtained by heel-prick from 18 neonatal intensive care patients as assessed by linear regression analysis (correlation coefficient: 0.966 for noradrenaline; 0.894 for adrenaline; p less than 0.05) and by a Wilcoxon test [noradrenaline: 2.13 (0.61-10.47) versus 2.41 (1.05-10.23); adrenaline: 0.75 (0.16-1.70) versus 0.72 (0.10-1.37) nmol/L, median (range)]. However, "arterialization" of capillary blood is important; when blood was obtained in nine neonates without warming their feet, capillary concentrations of noradrenaline were higher than arterial values (p less than 0.03) and those of adrenaline were not different from arterial values. Catecholamine concentrations in arterialized capillary plasma collected in healthy full-term infants at 1 h [n = 9; noradrenaline: 6.85 (3.09-8.88) nmol/L; adrenaline: 1.34 (0.86-2.85) nmol/L] and 5 d after birth [n = 27; noradrenaline: 1.58 (0.89-3.16) nmol/L; adrenaline: 0.59 (0.25-1.64) nmol/L] reflect the well-known fall (p less than 0.01) in catecholamine levels after delivery. With a highly sensitive analytical technique, catecholamine concentrations can reliably be assessed in minute samples (100-200 microL) of arterialized capillary blood, even when concentrations have dropped to low "resting" basal levels. Moreover, the capillary sampling procedure is simple and safe, can easily be applied to healthy infants, and does not have the practical and ethical limitations of arterial blood sampling.

Adrenal Glands↗
PubMed1992

A modular mock circulation for hydromechanical studies on valves, stenoses, vascular grafts and cardiac assist devices.

P6vices for hydrodynamic simulation are required in a variety of studies such as device evaluation, cardiovascular modeling and for student training. Most studies today use different, incompatible circuits, which must be redesigned for every new application. To obtain a universal apparatus, a unitized system with standard connectors was developed. Three types of connectors were selected: 1" flange connectors, 1/2" tubing connectors and Luer-connectors with a 2 mm lumen. The complete system consists of reservoirs, throttles, valve holders, adapters for Doppler ultrasound probes, and converters to link these basic diameters. The apparatus can be driven by membrane, centrifugal and geared pumps. The system has successfully been used in echocardiographic studies of stenosis and valvular insufficiency, for pulse propagation in vascular grafts, and to test the hydraulic performance of cardiac assist devices. Flow rates between 0.1 and 30 l/min and pressure gradients up to 250 mmHg were achieved. In practical use, the system can be adapted to suit various investigations, with minimal expense. Standardization of the parts and connectors results in simple documentation and good reproducibility.

Blood Circulation↗