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Biomedical subjects

F Mahler

Publications and source records attributed to F Mahler.

At least 19 recordsLinked to original sources
PubMed2001

[Treatment of peripheral arterial occlusive disease].

The choice of therapy for peripheral artery occlusive disease depends on functional stage, site and extent of vascular lesion, pathogenesis, and the individual needs of the patients. In stage I (according to Fontaine) the risk factors are sought and treated. In stage II walking exercise is the main pillar besides vasoactive drugs and secondary drug prevention. Transluminal angioplasty is recommended if vascular lesions are suitable (short stenoses or occlusions in iliac a/o femoro-popliteal arteries). Surgery may be performed in aorto-iliac arteries but only exceptionally in femoro-popliteal disease. In stage III/IV or chronic critical ischemia every possibility for revascularisation must be considered. In acute stages immediate therapy is necessary. In our hands catheter techniques (thrombolysis a/o aspiration) are the first line approach on the femoro-popliteal level while occlusions on aorto-iliac level are left to surgery.

Angioplasty, Balloon↗
PubMed2000

[Progress in endovascular therapy of peripheral arteries].

Percutaneous transluminal angioplasty introduced by Grüntzig nearly 30 years ago, remains one of the most often performed treatment for peripheral artery disease. Aortoiliac stenoses as well as short femoropopliteal occlusions are particularly prone to PTA approach. Because catheter intervention is not only limited to balloon dilatation but offers a wide variety of treatment, endovascular treatment tends to replace the generic term PTA. Recent progress in this field extend far beyond imaging improvement. They comprise new revascularisation techniques and lesions that were formerly considered to be solely treatable by surgery become curable by endovascular approaches. Combined treatment associating thromboaspiration with embolectomy in case of acute or subacute infrainguinal occlusions as well as low dose infiltration thrombolysis with or without additional PTA represent now first choice therapeutic interventions. The manufacturing of stents or stent-grafts represents one of the greatest breakthrough in the field of endovascular interventions. Stents have significantly improved post PTA patency particularly in the suprainguinal location. Furthermore, stent-grafts represent an attractive alternative to bypass surgery in a selected population, to exclude aortic aneurysm, mainly below the renal arteries. The last but not the least of the progress in the management of patients with peripheral artery disease is the multidisciplinary approach of the vascular problems by the specialist involved in cardiovascular diseases.

Angiography↗
PubMed2000

The pole-pressure test: an easy alternative in patients with ischemic legs and incompressible arteries.

BACKGROUND: Systolic ankle artery pressure measured classically by cuff-manometry and Doppler ultrasound in patients with severely ischemic legs may be falsely elevated because of impaired compressibility of the arteries. We evaluated a hydrostatic blood pressure or so-called pole pressure test by correlating the ankle artery pressure as well as tcpO2 with the pole pressure. PATIENTS AND METHODS: We enrolled 29 patients (18 male, 11 female, 10 diabetics) with critical leg ischaemia. The pole pressure was obtained by elevating the leg, and measuring the height at which the Doppler signal disappears by means of a calibrated pole (recalculating cm H2O for mmHg). We used an 8 MHz cw-Doppler device. Only pole pressure values up to 70 cm H2O were included. In addition tcpO2 at 45 degrees C was recorded at the forefoot of the same leg. RESULTS: When we included the values of the ten diabetic patients the pole pressure of 57.9 +/- 16.2 mmHg (mean +/- SD) was significantly lower by 40.7 mmHg than the ankle pressure of 98. +/- 38.4 mmHg, p < 0.0001 (paired t-test). Without the diabetics the difference was 33.7 mmHg. The correlation coefficient between pole pressure and ankle pressure was 0.546 including the patients with diabetes, and 0.609 excluding the diabetics. The correlation of tcpO2 with the pole pressure, however, was 0.624 regardless of the inclusion of diabetics, while that between tcpO2 and ankle pressure was only 0.250. CONCLUSIONS: The pole pressure test is an easy, inexpensive and fast method providing a meaningful, quantitative measure independent of the compressibility of the arteries.

Aged↗
PubMed2000

Renal artery stenting following acute aortic dissection: implantation and follow-up.

Two patients with renal artery involvement in type B dissection of the aorta were treated by percutaneous stent implantation. Both of them were hypertensive and showed increasing serum creatinine levels. After stent implantation in the renal arteries blood pressure and renal function improved, and the renal arteries were patent in duplex ultrasound 15 and 30 months after treatment respectively.

Aged↗
PubMed2000

Percutaneous catheter thrombus aspiration for acute or subacute arterial occlusion of the legs: how much thrombolysis is needed?

OBJECTIVE: To evaluate the role of a combined percutaneous endovascular approach including thrombus aspiration, catheter thrombolysis, and percutaneous transluminal angioplasty (PTA) to treat acute and subacute occlusions of native leg arteries. MATERIALS AND METHODS: Retrospective evaluation of the effectiveness and safety of this catheter therapy in 89 consecutive patients (93 legs) in a single centre. RESULTS: Treatment was initially successful in 90% of legs. Mortality at 30 days was 8%, and at 12 months 19%. Amputation-free survival at 12 months was 78%. Aspiration alone was sufficient in 31% of cases, urokinase (mean dose 112 500+/-55 900 IU) was used in 22%, PTA was added in 69%. There was no major bleeding except for one false aneurysm treated by ultrasound-guided compression. Secondary interventions within 12 months were required in 30% of cases (14 endovascular, 16 open surgical procedures). CONCLUSIONS: Catheter thrombus aspiration in combination with thrombolysis and/or PTA is highly effective. Only in a minority of patients are thrombolytics in modest doses necessary, and serious bleeding complications are rare. We recommend this procedure as first-line treatment for acute or subacute infrainguinal arterial occlusions.

Acute Disease↗
PubMed2000

Stent placement in ostial and nonostial atherosclerotic renal arterial stenoses: a prospective follow-up study.

PURPOSE: To compare the results of balloon percutaneous transluminal renal angioplasty (PTRA) and stent placement in atherosclerotic ostial, proximal, and isolated truncal stenoses. MATERIALS AND METHODS: Between January 1994 and April 1998 the authors prospectively followed up 163 consecutive patients with 200 atherosclerotic renal arterial lesions after primary PTRA or primary stent placement. Duplex ultrasonography was performed 1 day and 3, 6, and 12 months later. RESULTS: The primary 12-month PTRA patency rates were 34% (21 of 33 atherosclerotic lesions) for ostial stenoses, 65% (20 of 60) for proximal stenoses, and 83% (five of 30) for truncal stenoses (chi(2) value, 15.63; P <.001). The corresponding stent patency rates were 80% (four of 21), 72% (nine of 34), and 66% (five of nine), respectively (chi(2) value, 4.11; not significant). Significant stent-related reduction in risk of restenosis was limited to the ostial stenoses (P =.002). CONCLUSION: Renal arterial stent placement considerably improves patency in ostial stenoses, but compared with the technically successful PTRA, it does not significantly improve primary patency in proximal and isolated truncal renal arterial stenoses.

Adult↗
PubMed2000

Influence of the ultrasound contrast agent Levovist on human nailfold capillary microcirculation.

Little is known about the behavior of ultrasound contrast microbubbles in human capillaries. The evaluation of circulatory effects of echo contrast media may bring valuable information for the interpretation of echo contrast phenomena in the human myocardium. In 12 healthy volunteers (aged 31 +/- 6.7 years; five women), nailfold capillaries were examined by means of TV microscopy. The authors investigated acral microcirculation at rest and after local cold application with and without saccharide-based microbubbles (10 mL Levovist 300 mg/mL IV). The mean blood flow velocity at rest was 1.18 +/- 0.18 mm/s (mean value +/-1 SD) and 1.11 +/- 0.11 mm/s (mean value +/- 1 SD) after the injection of Levovist (ns). One minute after local cold exposure a decrease of the blood flow velocity by 61% before and by 75% after intravenous Levovist was found. In both groups the cold-induced decrease of blood flow velocity was statistically significant (p<0.01), whereas there was no significant difference in flow reaction between the two groups. No wall adhesion of blood cells or extravasation of contrast into the surrounding tissue was detected. After intravenous injection of a regular dose of saccharide-based microbubbles Levovist, no change of blood cell flow velocity and no wall adhesion or extravasation could be found at rest and after cold application in human nailfold capillaries. Since microcirculatory flow characteristics in the finger nailfold capillaries are not influenced by Levovist, it might be assumed also that myocardial blood flow behavior remains unchanged, so that this contrast agent may be used as a flow tracer for cardiac investigation.

Adult↗
PubMed1999

Stenting of the peripheral, renal and supraaortic arteries and the aorta.

In spite of the limited experience with the newer types of stents (covered stents, stent grafts) and the resultant reservations, this development is one of the most fascinating features of the last decade and opens new perspectives for vascular medicine and endovascular surgery in the near future. At present stents in the aortoiliac region, including the origin of renal arteries, appear to fulfil their promise. In the femoropopliteal and crural region there are still unresolved problems (relapse rate around 50%), and stents should be implanted only in salvage situations. However, primary application of stents cannot be recommended even in the unproblematic regions, due to the possibility of stent-induced intimal hyperplasia and the high cost of the devices. In other more controversial regions such as the carotid arteries, the application is still experimental and should be performed under controlled study circumstances.

Aged↗
PubMed1999

A prospective, randomized evaluation of nonsurgical closure of femoral pseudoaneurysm by compression device with or without ultrasound guidance.

Femoral artery pseudoaneurysm (PA) is a significant complication following diagnostic or therapeutic catheterization. The treatment of choice for femoral artery PA is freehand ultrasound-guided compression repair (UGCR). An alternative method is compression by mechanical devices. The study evaluated the mechanical compression device (FemoStop) with (G1) or without (G2) ultrasound guidance for initial placement in a randomized fashion. Thirty-eight patients (20 women, 18 men) age 40 to 85 (mean 54) years with clinical signs of PA underwent diagnostic color Doppler ultrasound. Randomization yielded 19 patients each for G1 and G2. PA occurred after 12 diagnostic cardiac catheterizations, 18 coronary stent implantations or balloon angioplasties, 2 electrophysiology procedures, and 6 peripheral percutaneous transluminal angioplasties. The G1 protocol was successful in 15 of 19 patients (79%), with a mean compression time of 28 min. The three other patients were treated successfully with UGCR. Only one patient needed vascular surgery. The G2 protocol was successful in 14 of 19 patients (74%) with a mean compression time of 33 min. The failed patients were treated successfully: three with UGCR and two with the same mechanical compression device now positioned under ultrasound control. Compression therapy with the compression device (FemoStop) for iatrogenic femoral pseudoaneurysm does not require ultrasound guidance for positioning. Cathet. Cardiovasc. Intervent. 47:304-309, 1999.

Aged↗
PubMed1999

PTA of the subclavian and innominate arteries: long-term results.

BACKGROUND: To investigate the long-term clinical and duplex sonographic results of percutaneous transluminal angioplasty (PTA) of the subclavian and innominate arteries, and the potential of a new double balloon technique to avoid cerebrovascular thromboembolism. PATIENTS AND METHODS: Forty-three PTAs were performed on 38 subclavian, four innominate arteries and one subclavian-subclavian bypass in 37 patients. In three instances a protective double balloon technique was used. Indication for the intervention was: subclavian steal syndrome (n = 14 [38%]), upper extremity arterial insufficiency (n = 26 [70%]), peripheral thromboembolism (n = 8 [22%]) and PRIND/stroke (n = 3 [8%]). Analysis of long-term follow-up (median 15, range 2 to 100 months) was possible of 28 patients including duplex sonographic assessment in 23 patients. The cumulative patency rate was calculated by means of life-table analysis. RESULTS: Technical success was achieved in 36 endovascular procedures (84%). Minor peripheral catheter complications occurred in three interventions (7%), cerebrovascular thromboembolism in four (9%). No cerebrovascular complications were seen using the double balloon technique. On final check-up 4 patients (14%) suffered from subclavian steal syndrome, 3 (11%) from mild upper extremity arterial insufficiency and one (4%) from rest pain. Duplex sonography showed no stenosis in 12 of 23 patients (52%) and a stenosis of less than 50% in 8 (35%). The life-table analysis showed a secondary cumulative patency rate of 72% after 100 months with all restenoses occurring within 24 months. CONCLUSIONS: PTA of the subclavian and innominate arteries appears to be a useful alternative to surgery with a low complication rate. The long-term patency rate of 72% is comparable to results of other series. In high risk situations cerebrovascular complications may be reduced using the new double balloon technique.

Adult↗
PubMed1999

New system for image analysis in nailfold capillaroscopy.

For quantitative evaluation of human TV nailfold capillary microscopy a new semi-automated image-analyzing system called "CapiShape" is presented. Skeletons and boundaries of capillaries are obtained by a special image processing algorithm to describe the shape of capillaries. In addition to conventional parameters such as diameters and loop widths for the size of single capillaries, new non-size parameters related to surface area and the skeletons are calculated. To describe capillary distribution in a nailfold, the ratio of distance between capillaries to its projection in the X axis, and area percentage are indicated. With different operators and different orientations of the camera, the measured differences in diameters and loop widths are smaller than 1.5 microm, and in area percentage smaller than 1.0%. As practical examples, applications of CapiShape to patients with scleroderma showed marked, significant differences in capillary size between patients and controls, patients with diabetes differed significantly in non-size parameters from controls. CapiShape is specially designed for clinical applications, and besides the usual measures new parameters for describing nailfold images may be developed. CapiShape is safe and easy to use for diagnosis, routine examination, and quantitative follow-up studies.

Adult↗
PubMed1998

Pseudoaneurysm of femoral artery after catheterisation: treatment by a mechanical compression device guided by colour Doppler ultrasound.

BACKGROUND: Femoral artery pseudoaneurysm is a significant complication in patients undergoing diagnostic or therapeutic catheterisation. First choice treatment for pseudoaneurysm is freehand ultrasound guided compression repair, which is time consuming and uncomfortable for the patient and operator. AIM: To explore a mechanical compression device (FemoStop) as an alternative treatment for iatrogenic femoral artery pseudoaneurysm. METHODS: Fourteen patients with pseudoaneurysm were considered for treatment with FemoStop after a brief freehand ultrasound guided compression repair to confirm the compressibility of the lesion. The FemoStop compression was applied for 20 minutes. The result was controlled with colour Doppler ultrasound, and a second cycle of 20 minutes followed if necessary. RESULTS: FemoStop compression was successful in 13 of the 14 patients. The mean compression time was 33 minutes (range, 20-60). The mean number of compression periods was 1.6 (range 1-3). FemoStop compression was successful in all 11 patients not taking anticoagulants and in two of three patients receiving anticoagulants. The mean compression time in patients given oral or intravenous anticoagulants was longer (50 v 27 minutes). Colour Doppler ultrasound 12 hours after the procedure indicated no recurrence of pseudoaneurysm in the 13 patients with initial success. CONCLUSIONS: FemoStop compression for iatrogenic pseudoaneurysm is feasible, and as safe and effective as freehand ultrasound guided compression repair. It is more comfortable for the patient and operator, and probably more economical than freehand compression.

Adult↗
PubMed1998

A New Approach to Plaque Removal: The Redha-Cut Device.

PURPOSE: To prospectively determine the safety, feasibility and efficacy of a new atherectomy device. Methods. Seventy patients with 93 symptomatic femoro-popliteal lesions underwent percutaneous atherectomy with Redha-cut, a metallic, flexible catheter. The device works on pull-back with two umbrella-like blades and enables cutting, retaining and removing of material. Quantitative analysis of the angiograms was performed. RESULTS: Obtaining of atherectomized samples was successful in all cases. The mean atherectomy time was 5 +/- 2 minutes. The stenoses were reduced from 74 +/- 2.3% before to 26 +/- 2% after atherectomy (p < 0.001). Subsequent PTA, which was performed to optimize the results, further decreased the degree of stenosis to 17% (p > 0.5). No perforations, acute closure or early re-thrombosis occurred. Cumulative patency rates according to the findings of non-invasiveive examinations were 83% at 6 months and 66% at 12 months. Conclusions. The Redha-cut device is a simple, safe and efficacious tool for biopsy sampling and atherectomy. Further studies randomizing patients either to balloon or atherectomy are planned to compare this technique with others in regard to long-term patency.

Journal Article↗