Biomedical subjects

F Grabenwöger

Publications and source records attributed to F Grabenwöger.

At least 19 recordsLinked to original sources

PubMed1996

Stenoses of the first segment of the vertebral artery: difficulties in angiographic diagnosis.

Pathology at the origin of the vertebral artery may be the cause of incapacitating vertebrobasilar insufficiency (VBI). Preoperative diagnosis is made primarily on angiographic criteria. We compared intraoperative and angiographic findings in 30 patients and found important diagnostic discrepancies in patients with a caudal, ventral or dorsal origin of the vertebral artery. In their angiograms, vessel superimposition led us to over look 3 ostial stenoses and 10 stenoses due to kinking. Angiographic assessment of patients with VBI can be difficult. Adequate visualisation of the origin of the vertebral artery is mandatory for accurate diagnosis.

Aged↗

PubMed1996

Spiral CT angiography: study of stenoses and calcification at the origin of the vertebral artery.

The origin of the vertebral artery may be difficult to show on sonography or conventional angiography. Our aim was to evaluate the accuracy of CT angiography (CTA) in detecting arteriosclerotic changes in the first segment (V1) of the vertebral artery. We performed CTA and intra-arterial digital subtraction angiography (DSA) on 24 patients with vertebrobasilar insufficiency. The ostium and the V1 segment were examined. Stenosis was assessed on a three-grade scale, and calcification and the degree of kinking were recorded. DSA and CTA results were compared. The ostium of the artery was seen in all cases on CTA and in 33 of 47 cases with DSA. All ostial stenoses diagnosed on DSA were seen with CTA. CTA revealed 4 stenoses in cases in which angiography proved inadequate, 11 zones of calcification and 5 cases of luminal reduction due to calcified plaques undetected on DSA. In the V1 segment DSA and CTA showed 3 stenoses, 9 cases of kinking, 1 of coiling and 4 stenoses due to kinking. CTA also demonstrated 4 additional stenoses, 2 cases of kinking and 3 stenoses due to kinking.

Aged↗

PubMed1996

Coefficient of variation: a powerful Doppler ultrasonographic parameter for detection of renal artery stenosis.

The aim of our study was to objectively compare the effectiveness of various Doppler parameters in the diagnosis of renal artery stenosis. In three sheep, variable degrees of renal artery stenosis were induced and renal segmental arteries were investigated using pulsed Doppler sonography. In each animal the standard deviation of the instantaneous peak velocity within one cardiac cycle normalized by the mean peak velocity (coefficient of variation) had significantly higher normalized regression coefficients (k* = -0.215, average of three animals) when compared to resistive index (k* = -0.090) and acceleration index (k* = -0.069). In each individual animal, coefficient of variation detected lower pressure gradients (6.3 mm Hg, average value) than did resistive index (13.4 mm Hg) or acceleration index (17.3 mm Hg). The coefficient of variation may detect the presence of pressure gradients in renal artery stenosis more accurately than acceleration index or resistive index.

Animals↗

PubMed1996

Pseudopericardial effusions in heart transplant recipients.

BACKGROUND: The objective of this study was to determine the nature of sonographically observed band-shaped, homogeneous, almost echo-free structures located ventral to the right ventricle of the heart in heart transplant recipients. METHODS: A total of 212 consecutive heart transplant recipients was evaluated sonographically. RESULTS: In 18 of the 212 patients (8.5%) band-shaped structures were detected, and these structures were proved with computed tomography or magnetic resonance imaging to be caused by mediastinal fat. CONCLUSIONS: A sonographically demonstrable, almost echo-free band-shaped structure located ventral to the heart should not be misinterpreted as localized pericardial effusion.

Adult↗

PubMed1995

Intrarenal Doppler ultrasonography: which vessel should be investigated?

The aim of our study was to determine whether the site of intrarenal Doppler measurement influences diagnosis of renal artery stenosis. In an experimental test, three sheep with variable degrees of renal artery stenosis were investigated. In each animal, the resistive index from renal segmental arteries correlated better with mean pressure gradient (r = 0.85, 0.71, 0.85) and had lower standard deviation (s = 0.02 to 0.05) than resistive index from interlobar arteries (r = 0.48, 0.54, 0.61) (s = 0.03 to 0.11). In two animals the difference was significant (correlation: P < or = 0.01, P = 0.13, P < or = 0.05; standard deviation: P < or = 0.01, P < or = 0.34, P < or = 0.05). For detecting renal artery stenosis, vessels within the renal sinus should be used for Doppler sampling.

Animals↗

PubMed1994

Mesh tube-calibrated varicose veins for coronary artery bypass grafting.

Complex arterial bypass grafting may be contraindicated for patients with multivessel disease and inadequate saphenous veins. In such cases varicose veins may be used as bypass conduits after calibration by insertion into mesh tubes. After in vitro and experimental testing, as well as gratifying results in infrainguinal arterial reconstructions, wrapped varicose vein grafts in addition to arterial bypass grafts were used in 6 patients undergoing coronary artery bypass grafting.

Calibration↗

PubMed1994

[Rate of thrombosis after cava filter implantation. Long-term results].

Thrombosis of the access site and occlusion of the inferior vena cava after placement of an inferior vena caval filter are known complications of caval interruption. 30 patients were evaluated with colour-coded Doppler sonography 4 to 66 months (average 2.5 years) after percutaneous placement of either a Günther filter, a Bird's Nest filter or a Simon-Nitinol filter. One right internal jugular vein had post-thrombotic alterations. One inferior vena cava was found to be occluded 15 months after Simon-Nitinol filter placement. The long-term occlusion rates of access site and inferior vena cava after percutaneous filter introduction are low. These two factors need not be considered if implantation of a caval filter is contemplated.

Adult↗

PubMed1994

Quantification of pleural effusions: sonography versus radiography.

PURPOSE: To develop a practical method of estimating the volume of pleural effusions with sonography. MATERIALS AND METHODS: Fifty-one patients underwent sonography of the pleural space while supine. Sonographic results and results of lateral decubitus radiography were compared with actual effusion volumes. The maximum thickness of the pleural fluid layer was measured with both modalities, while actual effusion volume was determined by means of complete drainage. RESULTS: Sonographic measurements correlated statistically significantly better with actual effusion volume (r = .80) than did radiographic measurements (r = .58) (P < or = .05). With sonographic measurement, an effusion width of 20 mm had a mean volume of 380 mL +/- 130 (standard deviation), while one of 40 mm had a mean volume of 1,000 mL +/- 330. Prediction error with sonographic measurement (mean, 224 mL) was statistically significantly less (P < or = .002) than that with radiographic measurement (mean, 465 mL). CONCLUSION: In quantification of pleural effusions, the sonographic measurement method presented is preferable to radiographic measurement.

Adult↗

PubMed1994

Aprotinin does not decrease early graft patency after coronary artery bypass grafting despite reducing postoperative bleeding and use of donated blood.

Forty-five male patients with planned coronary artery bypass operation were randomized in a double blind fashion to receive either 6 million kallikrein inactivator units of aprotinin (high-dose group), 2 million kallikrein inactivator units of aprotinin (low-dose group), or placebo (control group). Postoperative bleeding was significantly decreased in both aprotinin groups in comparison to that in the control group (590 ml [290 to 1800 ml] high-dose group and 650 ml [280 to 1900 ml] low-dose group versus 920 ml (350 to 2700 ml) control group, p < 0.001). There was no difference between the two aprotinin groups. The need for postoperative blood transfusion was significantly lower in the aprotinin groups (1.46 [0 to 4] blood units high-dose group and 1.65 [0 to 5] blood units low-dose group versus 2.43 [0 to 7] blood units control group, p < 0.05). All patients underwent coronary angiography between the seventh and twelfth postoperative day. No difference was found among the three groups in patency of vein grafts-93.8% in the high-dose group, 94.5% in the low-dose groups, and 93.3% in the control group. Therefore, aprotinin significantly reduced postoperative bleeding and transfusion requirement after coronary artery bypass grafting without influencing early graft patency.

Aprotinin↗

PubMed1993

Six-year follow-up after heart valve replacement with the Edwards Duromedics bileaflet prosthesis.

The Duromedics Edwards valve (DE) was designed with a self-irrigating hinge mechanism to reduce the rate of thromboembolic complications. This report presents a prospective follow-up of patients after valve replacement with this prosthesis in a university hospital. Five hundred seven patients had DE prostheses implanted in the aortic (n = 268), mitral (n = 183) or aortic and mitral positions (n = 56). The perioperative mortality was 6.9%. Follow-up was 98% complete, comprising 2009 patient years for a mean follow-up of 48 months: (range 27-84). The actuarial freedom from complications is calculated as follows (linearized rates in parentheses): late mortality 81.0 +/- 2.3% (3.4%/patient year), thromboembolism 93.5 +/- 1.5% (1.1%/patient year), anticoagulation-related hemorrhage 89.5 +/- 2.0% (1.9%/patient year), prosthetic valve endocarditis 96.0 +/- 1.2% (0.7%/patient year), valve-related mortality 93 +/- 1.8% (1.5%/patient year), valve failure 89 +/- 2.0% (2%/patient year), treatment failure 88.0 +/- 2.0% (2.2%/patient year) and all valve-related morbidity and mortality 74.0 +/- 2.8% (5.3%/patient year). Two events of leaflet escape were observed in the study group (0.09%/patient year). Both patients were reoperated successfully. Mechanical hemolysis was subclinical in all cases. The DE shows a complication rate comparable to other modern mechanical valve prostheses. After solving the problem of durability, reconsideration of this valve is worthwhile due to its low risk of thromboembolic complications.

Aortic Valve↗

PubMed1993

[Ultrasound-guided needle biopsies of thoracic space-occupying lesions].

This study is concerned with the results and experience gained from performing ultrasound-guided needle biopsies of thoracic masses in 56 patients. The accuracy of the biopsy results were related to the certainty of the method, the visibility of the biopsy needle on real time images, the effect of biopsy needle thickness and tumour size. Correct diagnosis was achieved in 84.6%. Inability to see the biopsy needle resulted in only 5.4% of cases and only when using a low frequency transducer (3 MHz). The thickness of the biopsy needle affected the accuracy of the biopsy, since all false negative or inconclusive biopsies resulted from the use of fine calibre needles. There was no significant correlation between tumour size and the accuracy of the biopsy results.

Adult↗

PubMed1993

[Stenoses and occlusions of the abdominal aorta in patients less than 40-years old].

Stenosis or occlusion of the abdominal aorta in patients under 40 years of age is either due to a congenital malformation (abdominal aortic coarctation) or due to idiopathic aortitis (Takayasu's arteritis). Some authors, however, consider abdominal aortic coarctation as a subtype of Takayasu's arteritis. We evaluated 9 of our cases and 108 well-documented cases from the literature to help decide the question whether abdominal aortic coarctation is an entity of its own or a subtype of Takayasu's arteritis. In coarctation there is a slight male predominance, patients are usually younger than 20 years of age, and the short aortic stenosis is suprarenal with involvement of the renal arteries. In Takayasu's arteritis females are predominantly affected, patients are usually over 20 years of age, and the long aortic stenosis or occlusion is infrarenal without involvement of the renal arteries. Abdominal aortic coarctation must therefore be considered as a separate disease. Aortography is important, because the morphology of aortic alterations often allows a radiological diagnosis.

Adult↗

PubMed1993

Use of varicose veins as arterial bypass grafts.

Varicose veins are not generally used as arterial bypass grafts despite their physiological endothelial flow surface. The large, irregular diameter and the thin wall renders these veins inadequate. Experimental studies have shown that a considerable reduction in the diameter of veins can be achieved by external wrapping without the generation of obstructing folds of the vein wall. A Dacron mesh tube surrounding varicose veins was used as a bypass graft in 13 infrainguinal arterial reconstructions. Ligated larger side branches and connections of the mesh segments caused irregularities of the otherwise smooth flow surfaces. Ten grafts were patent after a mean follow-up of 17 months. Two grafts have remained patent despite severe outflow obstruction in one and proximal occlusion in the other; both underwent successful interventions. The antithrombogenic properties of these grafts were partly due to a marked increase of the vasa vasorum. Externally constricted varicose veins may be used as arterial bypass conduits with good intermediate-term patency.

Aged↗

PubMed1993

[The radiologic clinical picture of primary bone lymphoma].

Primary lymphoma of bone is a rare form of non-Hodgkin lymphoma which involves a single bone and has a relatively good prognosis following radiation therapy. We observed 17 histologically verified cases and found 97 cases in the literature. This rare tumour may occur at any time in adults and usually affects the metaphyses of long bones. It produces osteolytic changes and usually only mild periosteal reactions. Radiologically as well as histologically, differentiation from other highly malignant bone tumours is extremely difficult and sometimes impossible. A correct diagnosis can only be made from an accurate knowledge of the radiological appearances, localisation of the tumour and age of the patient.

Adolescent↗

PubMed1992

Mesh tube--constricted varicose veins used as bypass grafts for infrainguinal arterial reconstruction.

Varicose veins are generally deemed inappropriate graft material for arterial reconstructions despite their physiologic flow surface because of their large and irregular caliber. Size reduction by threading such veins in constricting tubes may create bypass grafts of suitable caliber as long as redundant wall material does not cause stenoses. Sixteen human varicose veins (mean +/- SD, 13 +/- 3 mm diameter) obtained after stripping operations were inserted into Dacron mesh tubes of 6 mm internal diameter. Paraffin casts of the distended veins showed a size reduction of 6.9 +/- 2.6 mm. Wall material formed folds in only two veins. In both cases, diameter reduction was more than 10 mm. However, the folds did not result in significant stenoses. Mesh-constricted varicose veins were used as bypass material in 11 infrainguinal arterial reconstructions. All externally supported segments showed satisfactory size reduction without stenoses or folds. One graft occluded 2 months after surgery. Two patients had to undergo reoperation after 2 and 16 months, respectively. None of the complications could be attributed to the constriction of veins. The remaining grafts are patent and functional after a mean of 17 months (range, 6 to 42 months). Considerable size reduction by external wrapping of varicose veins is possible without adverse side effects. Such constricted veins were used successfully as bypass grafts for infrainguinal arterial reconstructions.

Aged↗

PubMed1992

Cardiac function, morphology and chromosomal aberrations in a calf with ectopia cordis cervicalis.

A male calf with ectopia cordis cervicalis inferior was investigated clinically, hemodynamically, and morphologically from the 3rd day of age until slaughter at the age of 22 months. Arterial hypertension (mean AOP 140 mm Hg), concentric myocardial hypertrophy and good ventricular contractility with normal valve function were found. Normal clinical condition at rest (cardiac output 48 l/min in the 600 kg bullock), but cyanosis and dyspnea during physical exercise were observed. Variations in the large vessels, such as persistence of the right cranial caval vein and one common pulmonary vein emptying into the left atrium, were found. Abrupt caliber differences of large arterial vessels together with a right angled aortic arch were observed, presumably contributing to increased afterload. The cytogenetic analysis showed the presence of a small marker chromosome leading to a chromosome number of 61 in a fraction of metaphases (mosaicism). Moreover, chromosome breakages were observed in many cells. From the 5 cows which were inseminated, 3 became pregnant. Ectopia cordis was not observed in any offspring. We conclude that in this animal compensated cardiac insufficiency with peripheral hypertension was established.

Animals↗

PubMed1992

Age-associated changes of the triangular fibrocartilage of the wrist: evaluation of the diagnostic performance of MR imaging.

To define the appearance of degenerative changes of the triangular fibrocartilage (TFC) of the wrist on magnetic resonance (MR) images, the TFCs in one wrist of each of 30 healthy subjects in three age groups (20-35, 36-50, and greater than 50 years) and six TFCs from fresh cadavers were examined by means of coronal T1-weighted spin-echo sequences. Histologic findings were compared with findings on MR images in the cadaveric TFCs. It was proved that patches or lines of signal hyperintensity within the cadaveric TFCs were caused by degenerative changes and tears. Similar changes of the TFCs on MR images of the healthy subjects may have been caused by degeneration. In the healthy subjects, degenerative changes of the TFC, usually well defined on MR images, occurred at a very early age. The TFC appears to undergo stages of degeneration comparable to those of the menisci of the knee, but differentiation between traumatic and degenerative tears may be difficult.

Adult↗

PubMed1992

[Surgery of blunt heart trauma].

Between 1972 and 1990 11 patients--all but one of them with multiple injuries--were treated surgically for blunt cardiac trauma caused by traffic accident in about 90%. Myocardial rupture (n = 3), laceration of the pericardial sac (n = 1), mitral insufficiency (n = 5; one of them in combination with atrial septal defect), ventricular septal defect (n = 1) and myocardial aneurysm (n = 1) occurred. Patients with myocardial rupture and pericardial laceration died within 2 h after admission to hospital; the other patients were successfully treated by mitral valve replacement (n = 4), mitral valvuloplasty and repair of ASD, suture repair of VSD and resection of myocardial aneurysm in one case, respectively. The interval to operation was 8 months to 12 years. Whereas pericardial tamponade caused by rupture of the atrial or ventricular wall and injuries of main coronary vessels require immediate surgical intervention, valve insufficiencies, septal defects or myocardial aneurysms may be mostly treated at a later date. Improvement of logistic measurements and the suspicion of blunt cardiac trauma followed by immediate surgical intervention may reduce the mortality rate in cases of cardiac rupture.

Adolescent↗