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Biomedical subjects

F Mahler

Publications and source records attributed to F Mahler.

At least 19 recordsLinked to original sources
PubMed1992

Double-blind, randomized comparison of systemic continuous infusion of 0.25 versus 0.50 mg/kg/24 h of alteplase over 3 to 7 days for treatment of deep venous thrombosis in heparinized patients: results of the European Thrombolysis with rt-PA in Venous Thrombosis (ETTT) trial.

Thirty-two patients with acute, proximal-vein thrombosis were treated with heparin and alteplase (0.25 versus 0.5 mg/kg/24 h during 3-7 days) in a randomized, double-blind, multicenter, European (ETTT) trial. The treatment resulted in a decrease of the venographic Marder's score from 18 (6-25) to 13 (2-24) units (median, range) in Group I (0.25 mg/kg/24 h, n = 15, median decrease 3.0, p = 0.32) and from 17.5 (3-33) to 15.5 (0-27) in Group II (0.5 mg/kg/24 h, n = 16, median decrease 4.0, p = 0.23). Comparison of the sequential venograms could be performed in 14 cases of Group I and in 15 cases in Group II. A minority of patients showed substantial partial recanalization of the initially obstructed veins on the control venogram (one in each treatment group) and most of the control venograms showed either thrombus size reductions (5 in Group I, 7 in Group II) or no change or even deterioration (8 in Group I, 7 in Group II). Major bleedings were observed in 7 patients (7/32, 22%), 5 of them occurring in Group II (5/17, 29%). Thus, the results of the ETTT trial show that the used low dosages of alteplase administered intravenously over 3-7 days in heparinized patients cannot be recommended as a treatment for patients with deep venous thrombosis of lower limbs and/or pelvis. Further studies are needed to define a more suitable dosage regimen of alteplase in this indication.

Adolescent↗
PubMed1992

Femoropopliteal artery occlusion: clinical experience with the Kensey catheter.

In 25 patients, 12 with acute-subacute and 13 with chronic extensive femoropopliteal artery occlusions (mean length, 8 cm), a prospective study was performed after application of the Kensey catheter and subsequent performance of percutaneous transluminal angioplasty (PTA). Passage through the occlusion with the Kensey catheter failed in five patients because of the presence of dissections. As confirmed at angiography, free flow through the obstruction and the runoff bed could be restored with the Kensey catheter, guide wires, balloon dilation, and thrombus aspiration and/or thrombolysis in 24 of the 25 patients (96%). In five patients, peripheral embolisms occurred after application of the Kensey or balloon catheter. Cumulative patency rates, according to findings of a noninvasive examination, were 80% at 3 days, 59% at 6 months, and 38% at 12 months after performance of the combined interventions. Thus, the results obtained with use of this new device have not proved superior to previously reported results with conventional PTA.

Aged↗
PubMed1992

Interventional angiology.

Percutaneous transluminal angioplasty in peripheral artery occlusive disease by balloon catheters is the standard method in interventional angiology. For almost twenty years it has been recommended in the aorto-iliac region for arterial stenoses, and in the femoro-popliteal arteries for stenoses and short occlusions. Due to progress in technology of catheters and guide wires, a primary success rate of more than 90% is to be expected with favourable angiographic conditions. The long-term patency rate of some 90% on the aorto-iliac level exceeds that of 70-90% on the femoro-popliteal level. The patency rate decreases with increasing complexity of the lesions. Subacute/acute occlusions of the femoro-popliteal arteries by thrombosis or embolism are treated successfully in 80% of cases by catheter-thrombolysis and/or thrombus aspiration combined with percutaneous transluminal angioplasty if necessary. Several new techniques are under clinical evaluation, such as laser angioplasty, rotational catheters, atherectomy catheters and stents. Their application in clinical routine has up to now not been justified except for special situations such as obtaining biopsy material by Simpson catheter or maintenance of patency in balloon resistant lesions by stents.

Angiography↗
PubMed1992

[Diagnosis of deep venous thrombosis].

The clinical diagnosis of deep venous thrombosis (DVT) is unreliable. Phlebography, an invasive method, has gained wide diffusion and is considered as gold standard, but it has several draw-backs such as elevated costs and x-ray exposure. For these reasons, other, non-invasive techniques for diagnosing DVT have been looked for. Among them, CW-Doppler, occlusion plethysmography and, more recently, colour-Duplex-sonography have gained most acceptance. While the first two methods are able to diagnose with sufficient sensitivity and specificity proximal DVT, they are unreliable for isolated calf vein thrombosis. The colour-Duplex-sonography, on the other hand, produces results similar to phlebography for proximal thrombosis and succeeds in detecting isolated calf vein thrombosis with sufficient accuracy. We propose therefore the following non-invasive proceeding when confronted with the question of DVT: The first investigation to be done is a (colour)-Duplex examination. If one lacks such an infrastructure, an investigation with CW-Doppler or occlusion plethysmography has to be performed. If the results are positive, the patient will be treated. Otherwise, the exam will be repeated after five to seven days for CW-Doppler and plethysmography. If now the result is positive, the patient will be treated, otherwise, as with a negative Duplex study, the suspicion of DVT will be dismissed.

Blood Flow Velocity↗
PubMed1992

Plasmapheresis for hyperviscosity syndrome in macroglobulinemia Waldenström and multiple myeloma: influence on blood rheology and the microcirculation.

The efficacy of plasmapheresis in improving blood flow properties in patients with hyperviscosity syndrome was studied during 22 plasmapheresis treatments in four patients with hyperviscosity syndrome (three with macroglobulinemia Waldenström, one with multiple myeloma). Immediately before and after plasmapheresis (exchange volume 3 liters) the following parameters were determined: standard hematologic parameters, serum proteins, plasma viscosity, whole blood viscosity, and blood flow velocity in finger nailfold capillaries by video microscopy. The hematocrit remained unchanged. Paraprotein concentrations were markedly reduced by plasmapheresis (average 35%). Plasma viscosity fell from 5.0 +/- 3.3 cp to 2.1 +/- 1.0 cp (p less than 0.0001, normal range 1.1 to 1.4 cp). Whole blood viscosity changed accordingly. The plasma viscosity before plasmapheresis (x) determined the drop in viscosity after plasmapheresis, according to the following regression: y = 0.97 - 0.77 x; r = 0.962, p less than 0.001. The spontaneous capillary blood cell flow velocity increased from 0.33 +/- 0.14 mm/sec to 0.55 +/- 0.21 mm/sec (p less than 0.01) and the change in spontaneous flow velocity (y) was correlated with the change in plasma viscosity (x): y = 0.02 - 0.05 x; r = 0.833, n = 7, p less than 0.05. We conclude that plasma viscosity is a major determinant of capillary blood flow and that plasmapheresis is an efficient treatment of abnormal microcirculation caused by increased plasma viscosity. Our data make it possible to predict the benefit of plasmapheresis in a given situation and contribute to a better use of this valuable method.

Blood Cells↗
PubMed1991

[Interventional angiography].

Percutaneous transluminal angioplasty (PTA) by balloon catheters is the standard method in interventional angiology. It is recommended in the aorto-iliac region for arterial stenoses, and in the femoro-popliteal arteries for stenoses and short occlusions. Due to progress in technology of catheters and guide wires, a primary success rate of more than 90% is to be expected with favorable angiographic conditions. The long-term patency rate of some 90% on the aorto-iliac level exceeds that of 70-90% on the femoro-popliteal level, with the patency rate decreasing with increasing complexity of the lesions. Subacute/acute occlusions of the femoro-popliteal arteries are treated successfully in 80% by catheter-thrombolysis and/or thrombus aspiration. Several new techniques are under clinical evaluation, such as laser angioplasty, rotational catheters, atherectomy catheters and stents. Their application in clinical routine has up to now not been justified except for special situations such as obtaining biopsy material by Simpson catheter or maintenance of patency in balloon resistant lesions by stents.

Angioplasty, Balloon↗
PubMed1991

Increased collagen around deformed finger nailfold capillaries in type I diabetes mellitus.

Quantitative finger nailfold capillary microscopy was performed in 25 patients with type I diabetes and in 27 healthy control subjects. In the last consecutive 6 patients and 7 controls of these populations, finger nailfold biopsies were taken. Measurements of loop width as an in vivo parameter for deformities of the capillary loops showed significantly higher values in diabetic patients than in controls. Histopathological examination showed markedly and significantly increased deposition of collagen in nailfold dermal papillae of the diabetic patients. The deposition of collagen was positively correlated with the number of capillary endothelial cells in the nailfold dermal papillae and with the size of the papillae in diabetic patients. It is concluded that, in addition to deformity of nailfold capillaries, collagen deposition may also be a sign of metabolic disturbance and perhaps of proliferation of capillary endothelial cells in diabetic microangiopathy.

Adult↗
PubMed1991

Quantitative nailfold capillary microscopy in cutaneous and systemic lupus erythematosus and localized and systemic scleroderma.

Quantitative television microscopy of nailfold capillaries of the fingers was performed in 12 patients with cutaneous lupus erythematosus (six with discoid type and six with disseminated type), in six patients with localized scleroderma (two with circumscribed type, two with linear types, and two with atrophic type), in 10 patients with systemic lupus erythematosus, and in eight patients with systemic scleroderma. The following features were analyzed and compared with a control group (n = 15) of similar age: venous plexus visibility; density of capillaries; avascular fields; hemorrhages; giant capillaries; diameters of the transitional segment, the arterial, and the venous limbs; loop width; and flow stop caused by local cooling test. The patient groups with cutaneous lesions only showed no essential differences as compared with the controls. Patients with systemic scleroderma differed in almost every finding from the controls and from patients with localized scleroderma. Patients with systemic lupus erythematosus exhibited significant differences in several findings as compared with the controls and the cutaneous lupus erythematosus group, but there was overlap.

Adolescent↗
PubMed1991

Comparative evaluation of three ambulatory plethysmographic devices as regards accuracy and handling in daily practice.

We compared a computed strain gauge plethysmograph (SGP1) with a Gutmann strain gauge plethysmograph (SGP2) and a photoplethysmograph (PPG) in 24 normal and 12 radiologically proven postphlebitic limbs with respect to assessment of the calf pump function, discrimination between normal and pathologic values, and handling. Recovery time (RT50), refilling volume (RV) and the Index (RT50xRV) were measured at the ankle and the calf in each limb after 20 dorsiflexions of the feet in the sitting position. The PPG device could only measure RT50. There was a strong positive correlation in RT50, RV and Index values between SGP1 and SGP2 at the ankle and at the calf (p less than 0.001), but none in RT50 ankle and calf values between PPG and SGP1 (p = 0.1) and PPG and SGP2 (p = 0.1). The comparison between normal and postphlebitic limbs revealed significant differences for all three values RT50, RV and Index only for SGP1 ankle measurements (p less than 0.02, p less than 0.01, respectively). Ankle RT50 values were significantly longer than calf RT50 values for both strain gauge devices (p less than 0.01), where PPG results were not influenced by the site of measurement. The average number of tests required to obtain a valid curve in each limb at the ankle and calf was lowest for SGP1 measurements. Vein calf pump function is easily and accurately assessed by SGP1 ankle measurements. However a threshold limit between normal and pathologic values can not be defined either for RT50 or for RV values in the individual case, and the creation of an Index adds little to solve this problem.

Adult↗
PubMed1991

Magnetic resonance angiography of abdominal vessels: early experience using the three-dimensional phase-contrast technique.

Based on three-dimensional acquisition of three sequences sensitive to one flow-direction, abdominal magnetic resonance phase-contrast angiography (MRA) was performed in 13 volunteers and 20 patients. The subjects received no antiperistaltic medication and were allowed to breath normally during the three acquisition periods of 11 minutes. The frequency of demonstration of the normal aorta, superior mesenteric and right and left renal arteries was 100%/100%/91%/100%, and of the inferior vena cava, splenic, superior mesenteric and portal veins was 92%/67%/92%/100%, respectively, whereas other abdominal vessels were seen less constantly. In renal artery stenosis or occlusion, MRA detected eight out of nine pathological arteries, missed only a minimal stenosis and was never false positive. In all 10 cases of portal hypertension, MRA demonstrated the venous collaterals detected by conventional angiography and in six cases showed more collaterals, particularly paravertebral vessels. A Budd-Chiari syndrome was investigated as well. If the accuracy of MRA can be proved in larger studies, it may become an important diagnostic tool in evaluating abdominal vascular pathology, such as renal artery stenosis or portal hypertension.

Abdomen↗
PubMed1991

[Mapping of superficial veins for vascular replacement using duplex ultrasound].

With regard to surgical vascular reconstruction, we evaluated the saphenous veins of 110 patients as potential substitute vessels by duplex ultrasound. The technique is analogous to the one used for diagnosis of varicose veins. Finally 74 patients underwent a surgical intervention with exploration or removal of veins. The comparison between the 74 operative findings available for analysis and the results of duplex ultrasound showed agreement in 93%. The duplex technique informs not only about the permeability and morphology of the veins but also by direct skin marking about their precise position. In comparison with phlebography, it is in experienced hands at least as reliable, without morbidity and virtually without inconvenience to the patient. In our opinion, the non-invasive duplex ultrasound method is quite adequate for the preoperative judgement of veins destined for vessel replacement.

Aged↗
PubMed1991

[Recent instrumental developments in percutaneous transluminal angioplasty (PTA)].

In addition to the balloon-catheter for PTA a number of new devices have been developed in recent years. Among them the most outstanding are laser beam application, mechanical devices for recanalization and endoprostheses for stenting of the vessels. The initial fascination by laser technique in PTA has given way to a matter-of-fact appreciation of the method. Up to now no available laser system achieves better clinical results than conventional PTA in the long run. Although there is much potential in the laser principle, it still is to be regarded as experimental. As for mechanical devices the fast rotating Kensey-catheter has not been proven superior to balloon PTA in our hands neither to remove organized or fresh thrombotic occlusive matter. A slowly rotating catheter (Rotacs) facilitates primary recanalisation of long occlusions prior to balloon dilatation. Atherectomy by the Simpson-catheter provides samples for histological studies but is indicated only in special situations. Numerous other mechanical percutaneous endarterectomy devices are under development, but clinical long term evaluation is not yet available. Vascular stents - self expandable or balloon expandable systems - may serve to keep the newly dilated arterial lumen open and to prevent late recurrences. While in larger vessels such as iliac arteries or aorta good long-term results after insufficient PTA were shown, other indications are still experimental. For all of these newer technologies both their relative effectiveness and the extent to which they may compare with or complement balloon PTA remain to be determined.

Angioplasty, Balloon↗
PubMed1990

[The diabetic foot].

The socio-economic, medical and psycho-social consequences of lower-limb injuries in diabetic patients are enormous. The risk of lower extremity amputation is 15 times greater in diabetic patients than in the age-matched non-diabetic population. About 1000 diabetic patients undergo a disabling amputation annually in Switzerland. Implementation of appropriate educational and foot-care programmes by motivated pluridisciplinary teams may reduce major amputations by as much as 50%. Regular examination of the feet of diabetic patients, therefore, deserves the same priority in diabetes care as control of the optic fundus and of kidney function, but unfortunately this is seldom the case. These guidelines summarize the physiopathology, the diagnosis and the treatment of diabetic foot problems. Emphasis is placed on simple preventive measures which should help protect the majority of high-risk patients.

Diabetes Complications↗
PubMed1990

Do vasospasms provoke ocular diseases?

Vasospasms in the eye are often combined with digital vasospasms, as can be diagnosed with a nailfold capillaroscopic local cooling test. In 16 patients with a history of cold hands and feet the presence of peripheral vasospasms without any underlying disease was demonstrated by means of nailfold video-capillaroscopy. These patients showed the phenomenologic diagnosis of low-tension glaucoma with visual field defects characteristic of glaucoma even though intraocular pressure above 21 mmHg was excluded. The visual field defects were not homonymous, indicating a prechiasmal location of the vascular disturbance. Ocular vasospasms cause visual field damage that can be aggravated or provoked by cooling one hand in cold water and that often improves after treatment with the calcium channel blocker nifedipine. The results suggest that vasospasms not only are present in Raynaud's disease, migraine, and Prinzmetal's variant angina but also may be an important factor in the genesis of low-tension glaucoma. This is a new finding and may be related to a general vasospastic syndrome.

Adolescent↗