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Biomedical subjects

F Mahler

Publications and source records attributed to F Mahler.

At least 55 records · Page 3Linked to original sources
PubMed1997

Unusual pseudoaneurysms after catheterization: successful treatment by ultrasound-guided compression.

Postcatheterization pseudoaneurysms occur mostly in the femoral artery. Two patients (both women, aged 67 and 59 years) undergoing percutaneous transluminal angioplasty (PTA) at our institution presented pseudoaneurysms in unusual locations, one in the brachial and one in the popliteal artery. Because of good experiences with ultrasound-guided compression repair (UGCR) in the femoral artery, we also successfully performed this noninvasive treatment on the two patients. Follow-up at 28 and 12 months, respectively, after the procedure, showed no instances of recurrence. As with the excellent results of UGCR in the femoral artery, we believe that this new modality is also the treatment of choice in iatrogenic pseudoaneurysms of the arm and popliteal arteries.

Aged↗
PubMed1997

Discriminative microcirculatory screening of patients with refractory limb ischaemia for dorsal column stimulation.

OBJECTIVES: (1) To determine the proportion of patients with critical limb ischaemia refractory to invasive treatment that can be successfully treated by dorsal column stimulation (DCS), and (2) to identify potential responders to DCS by a simple test that is sufficiently predictive to limit the need for a prolonged trial stimulation period. PATIENTS AND METHODS: Twenty patients with chronic limb-threatening ischaemia were assessed by a battery of macro- and microcirculatory tests and a DCS trial of 1 week. Favourable response during the trial determined selection for long-term stimulation. RESULTS: During a mean observation period of 14 months, limb salvage rate (LSR) was 63% overall and 83% among patients selected after a favourable trial. Of the tests performed preoperatively, digital subtraction angiography, Doppler assessment, oscillometry, capillaroscopy, foot temperature, and transcutaneous partial pressure of oxygen (tcpO2) in the supine or sitting position did not adequately predict DCS response. The supine-sitting tcpO2 gradient (delta tcpO2) was a good predictor of DCS outcome, with an 88% LSR when delta tcpO2 > 15 Torr, dropping to 12% when delta tcpO2 < or = 15 Torr. CONCLUSIONS: DCS is a rewarding therapeutic option in selected patients with critical limb ischaemia. delta tcpO2 appears to reliably predict response to DCS and may obviate trial stimulation in most cases.

Adult↗
PubMed1997

Patency of percutaneous transluminal renal angioplasty: a prospective sonographic study.

Evaluation of percutaneous transluminal renal angioplasty (PTRA) is today based primarily on clinical criteria rather than direct investigation of luminal width. In this study, we examined renal blood flow by color-coded duplex sonography (CCD) in order to correlate blood pressure as well as renal function with the true renovascular patency. Fifty consecutive patients suspected of suffering from renovascular disease and treated by PTRA were included for a prospective sonographic study. In all PTRA was performed on 63 renal arteries. Thirty-seven patients were diagnosed to have atherosclerosis and 13 patients to have fibromuscular dysplasia (FMD). Examinations were performed using CCD before PTRA, and one day, three months, six months and 12 months after PTRA. If CCD showed a restenosis > or = 60%, CCD was non-conclusive or hypertension deteriorated, angiography and, if necessary, catheter re-intervention were performed. The primary patency rate after 12 months was 73%, and could be improved to 94% overall when treated restenosis (N = 22) were included. Restenosis was more frequent in patients with mild residual stenosis identified by CCD one day after PTRA (P = 0.002). There was neither a significant difference in the restenosis rate in patients with atherosclerosis versus FMD, nor in patients with ostial versus non-ostial lesions. Hypertension was improved or cured in 70% of patients with atherosclerosis, and in 85% of those with FMD. Nevertheless, hypertension deteriorated in 12% of the patients without restenosis, and no deterioration was present in 14% of the patients with restenosis. A decrease in serum creatinine levels by more than 15% was observed in 12 of 22 patients with impaired renal function and patent renal artery during follow-up. These results suggest that optimal therapeutic efficiency can be obtained using PTRA followed by systematic CCD.

Adult↗
PubMed1997

Granulated polyamide as external marker to estimate total faecal excretion of grazing cattle in extensive management systems.

Granulated polyamide (PA) was tested for use as an external marker to estimate faecal DM (FDM) excretion of Zebu cattle (Bos indicus). The study was conducted in Mali, using seven and eighteen animals respectively in four field trials and six indoor experiments. Cattle ate fresh or dry pasture vegetation and half the animals were additionally supplemented with crop byproducts. Gelatine capsules containing 35, 40 or 45 g PA were administered orally at 12 h intervals. Estimates of FDM were based on the average marker concentration in faeces and were correlated with the actual excretion measured by total faecal collection. The pre-measurement period required to establish equilibrium for regular marker dosing was determined at 4 d. Except for diets with a N content of less than 9.26 g/kg organic matter, marker recovery averaged 98.1 (SE 0.93)% (n 62), and was not influenced by diet composition and the quantity of feed ingested (P > 0.05). Estimates of FDM based on average PA concentrations in faecal samples were correlated to the actual excretion with r 0.98 (n 62; P < or = 0.001). Since the PA concentration in individual faecal grab-samples is not correlated with either sample mass or sampling time, accurate estimates of FDM require a grab-sampling schedule that covers the 24 h day. However, estimates of FDM were found to be acceptable if calculations are based on the average PA concentration in the sub-total of samples collected during the day or during night respectively (r 0.95, n 29; P < or = 0.001 in both cases). It is concluded that the use of PA marker is a simple and inexpensive method resulting in reliable estimates of FDM. Since sophisticated analytical procedures are not required to recover PA in faecal samples, the marker is particularly suitable for application in extensive grazing systems and in studies conducted in less-developed countries.

Analysis of Variance↗
PubMed1997

Adventitial cystic disease of the popliteal artery: percutaneous US-guided aspiration.

PURPOSE: To evaluate percutaneous ultrasound (US)-guided aspiration as an alternative therapy for adventitial cystic disease. MATERIALS AND METHODS: Between September 1993 and June 1996, seven patients (six men, one woman; age range, 42-62 years; mean age, 48 years) presented with symptomatic adventitial cystic disease of the popliteal artery (one patient with subacute foot paresthesia, six patients with chronic calf claudication). Color Doppler sonography showed stenosis due to eccentric cysts. Five of the patients also underwent digital subtraction angiography, and four patients underwent magnetic resonance imaging. With real-time sonographic guidance, a 14-gauge needle was forwarded percutaneously into the cysts for aspiration. The aspiration procedure was performed on an outpatient basis with local anesthetics. RESULTS: The procedure was technically and clinically successful in all cases. No complications were noted. Follow-up color duplex sonography performed between 1 and 32 months (mean, 14.8 months) after the procedure showed no relevant recurrent stenosis. CONCLUSION: Percutaneous US-guided aspiration is an easy, safe, efficacious method for treating adventitial cystic disease. In symptomatic patients who do not have thrombotic occlusion, it may be considered the treatment of choice.

Adult↗
PubMed1997

Acute inflammatory reaction associated with endoluminal bypass grafts.

PURPOSE: Nonspecific inflammatory reactions characterized by local tenderness, fever, and flu-like discomfort have been seen in patients undergoing endoluminal graft placement in the abdominal aorta or the femoral arteries. We undertook a study to assess the clinical and laboratory parameters of this inflammation. METHODS: Ten patients with femoropopliteal artery (n = 9) or aortic (n = 1) lesions were treated with EndoPro System 1 stent-grafts made of nitinol alloy and covered with a polyester (Dacron) fabric. Eleven patients implanted with a bare nitinol stent served as the control group. RESULTS: In the stent-graft group, four patients showed clinical signs of acute inflammation manifested by fever and local tenderness. Three of these patients suffered thrombosis of the stent-grafts during the first month of follow-up. Plasma levels of interleukin-1 beta and interleukin-6 in all stent-graft patients were markedly increased 1 day after intervention (7.3 +/- 2.8 versus 90.2 +/- 34.1 pg/mL and 15.6 +/- 5.8 versus 175.5 +/- 66.3 pg/mL, respectively; p < 0.01). This was followed by an increase in fibrinogen (3.0 +/- 0.2 versus 5.0 +/- 0.2 g/L; p < 0.05) and C-reactive protein (14.6 +/- 3.3 versus 77.5 +/- 15.0 mg/L; p < 0.01) at 1 week. No direct correlation between the inflammatory markers and symptoms could be found. In vitro analysis showed that individual components of the stent-graft did not activate human neutrophils, whereas the intact stent-graft itself induced a marked neutrophil activation. CONCLUSIONS: The component of the self-expanding stent-graft responsible for the nonspecific inflammatory reaction was not identified in this study. It is likely that the stent-graft itself or some as yet unrecognized element of the device other than the Dacron fabric or metal alloy may be a potent in vivo inducer of cytokine reaction by neutrophils.

Aged↗
PubMed1996

Ultrasound-guided compression repair for treatment of femoral artery pseudoaneurysm: acute and follow-up results.

Femoral artery pseudoaneurysm is a significant problem in patients undergoing arterial diagnostic or therapeutic catheterization. The aim of this investigation was to report the incidence of pseudoaneurysm after arterial catheterization and the success rate of ultra-sound-guided compression repair. During a 3-year period (11/91-11/94) 9,051 patients underwent 7,312 cardiac catheterizations and 1,739 peripheral percutaneous transluminal coronary angioplasty procedures. Patients suspect of pseudoaneurysm were referred for a color Doppler ultrasound examination. All patients with pseudoaneurysm were considered for ultrasound-guided compression repair. Pseudoaneurysm occurred more frequently after interventional procedures with new devices (valvuloplasty 2.3%, stent 3.2%) than after conventional catheterization diagnostic cardiac catheterization 0.2%, electrophysiology 1.3%, percutaneous transluminal coronary angioplasty 0.2%). The incidence of pseudoaneurysm after peripheral percutaneous coronary transluminal angioplasty, including intra-arterial lysis and stent, was 1%. Ultrasound-guided compression repair was successfully performed in 37 of 41 cases with pseudoaneurysm (90%). Ultrasound-guided compression repair was successfully performed in 30 of 31 patients (97%) without anticoagulation and in 7 of 10 patients (70%) receiving anticoagulants (P < 0.05). There was no correlation between mean diameter of the pseudoaneurysm, age of the lesion, or antiplatelet therapy. Color Doppler ultrasound re-examination at up to 3 months indicated successful treatment in all patients. The use of complex interventional catheterization procedures leads to an increased frequency of pseudoaneurysms compared with conventional angiography and percutaneous transluminal coronary angioplasty. Ultrasound-guided compression repair is a non-invasive, efficient, safe and cost-effective therapy for post-catheterization pseudoaneurysm.

Adult↗
PubMed1996

Ultrasonic-pathologic comparison of postangioplasty myointimal hyperplasia and primary atheroma of the superficial femoral artery.

The purpose of this study was to characterize postangioplasty myointimal hyperplasia as compared to primary atheroma of superficial femoral arteries using color-coded duplex sonography (CCD), and to correlate sonographic findings with the histopathology of samples obtained from these lesions by catheter atherectomy (Redha-cut device). Preinterventionally, homogeneity, echogeneity, and the surface of plaques were described using CCD in nine cases with secondary stenoses after percutaneous transluminal angioplasty and in seven cases with primary atheroma. Myointimal hyperplasia of femoral restenoses showed a homogeneous (7 of 9 vs. 1 of 7) and hypoechogenic (7 of 9 vs. 0 of 7) wall thickening compared to primary atheromas (p < 0.05). Primary atherosclerotic plaques showed a rather heterogeneous, hypo- and hyperechogenic ultrasonic appearance with or without echo shadowing in six of seven cases. The surface of restenoses was more often regular than that of primary atherosclerotic lesions, but this finding did not reach statistical significance (6 of 9 vs. 2 of 7, p = 0.14). Thrombotic material appeared homogeneous and hypoechogenic in three of five cases and could not be discriminated from intimal hyperplasia. In summary, postangioplasty intimal hyperplasia is characterised by a hypoechogenic, homogeneous, rather regularly confined vessel wall thickening and can be differentiated from primary atheroma at CCD.

Aged↗
PubMed1996

[From the history of thrombosis prevention and treatment].

Rudolf Virchow described not only his famous triad in the 1840s but also the relationship between thrombosis and pulmonary embolism. Deep vein thrombosis (DVT) was recognized as postoperative complication from the 1890s. The preventive measures were directed against the factor blood stasis until heparin was applied clinically in the 1930s. The Swiss surgeon K. Lenggenhager was probably the first who recommended low dose heparin prophylaxis in 1940 on a rational experimental basis. Perhaps because his results were published only in German this application form became not popular before the great studies of Kakkar in the 70s took place. The introduction of low molecular weight heparins in the 80s simplifies prophylaxis and therapy of DVT again. The descriptions of deficiency of natural coagulation inhibitors start with antithrombin III in 1961. The recent discovery of the molecular basis of activated protein C resistance made history today.

Anticoagulants↗
PubMed1996

[Assessment of deep venous thrombosis].

Deep vein thrombosis (DVT) is a frequent disorder, which should not be missed diagnostically because of the associated morbidity and mortality due to pulmonary embolism and the postthrombotic syndrome. Clinical diagnosis is unreliable. Because of the possible risks a treatment by anticoagulation should not be undertaken without objective confirmation of DVT. Venography is generally considered as the gold standard for the diagnosis of DVT, but is invasive and associated with side effects. Noninvasive cw-Doppler ultrasound and the plethysmography are simple methods, but the accuracy is sufficient only for symptomatic proximal DVT and not for isolated DVT of the calf. In the past few years (color-coded) venous duplex imaging gained increasing importance. It is a noninvasive test with an accuracy comparable to that of venography. In addition to vascular changes perivascular structures can be investigated. B-mode compression sonography has a comparable accuracy for symptomatic proximal DVT.

Humans↗
PubMed1996

[Initial clinical results in the treatment of peripheral arterial occlusive diseases using new percutaneous atherectomy equipment (REDHA-CUT)].

In 11 female and 13 male patients 29 symptomatic femoropopliteal occlusions were treated with a novel intraluminal endarterectomy device (REDHA-CUT). The pre-existing stenoses (71 +/- 9%) could be reduced to 29 +/- 18% (means +/- s.d.). The arteriectomy procedure with this device took on average 5 +/- 3 min. Neither perforations nor dissections nor distal embolisms or any other complications were observed. In comparison with other percutaneous transluminal angioplasty procedures the clinical use of the novel REDHA-CUT device is safe, simple and fast and allows for the retrieval of plaque biopsies.

Aged↗
PubMed1996

17 beta-estradiol inhibits proliferation and migration of human vascular smooth muscle cells: similar effects in cells from postmenopausal females and in males.

OBJECTIVES: Cardiovascular disease is rare in premenopausal women, but increases after the menopause when hormone replacement therapy reduces coronary events. Vascular smooth muscle cell (SMC) proliferation and migration occur in atherosclerosis, restenosis and venous graft disease. We studied the effects of 17 beta-estradiol on SMC proliferation and migration. METHODS: SMC were cultured from saphenous veins of postmenopausal women and age-matched men. Cell growth was determined by 3H-thymidine incorporation and cell counting. Migration of SMC was assessed in 4-well chambers. SMC were seeded in one corner and PDGF-BB in filter paper glued onto the opposite wall. RESULTS: PDGF-BB (5 ng/ml for 24 h) similarly stimulated 3H-thymidine incorporation in female (511 +/- 57%; n = 8) and male (528 +/- 62%; n = 12) SMC. This was reduced by 17 beta-estradiol (10(-8)-10(-6) M; female 313 +/- 52%; male 337 +/- 54%; P < 0.05). PDGF-BB increased the number of SMC (P < 0.0001 at 10 days) obtained from females (153 +/- 3%; n = 5) and males (150 +/- 4%; n = 5), which was inhibited by 17 beta-estradiol (10(-6) M; female 134 +/- 7%; male 128 +/- 5%; P < 0.05). Similar results were obtained with basic fibroblast growth factor. In contrast to 17 beta-estradiol, another steroid (dexamethasone) had no effects on 3H-thymidine incorporation in these cells stimulated with PDGF-BB, PDGF-BB (0.01-1 ng) stimulated SMC migration (P < 0.05) which was inhibited by 17 beta-estradiol (10(-10)-10(-6) M; n = 5; P < 0.005). CONCLUSION: 17 beta-Estradiol inhibits growth-factor-induced SMC proliferation and migration regardless of gender. These effects of 17 beta-estradiol may contribute to its cardiovascular protective properties in postmenopausal women during replacement therapy.

Aged↗
PubMed1995

[Arterial stenting versus vascular replacement].

Stenting or transluminal implantation of vascular endoprostheses is a new modality among many endovascular techniques. Experience is greatest in the iliac arteries where patency rates above 90% are reported. Because in femoropopliteal arteries the patency rates are below 70%, stents should be implanted only in situations where percutaneous transluminal angioplasty (PTA) alone has failed. Similar results are obtained with implantation in renal and supraaortic arteries. Application in great veins for palliation of tumor compression seems to be a good indication. A new perspective opens up with "covered stents" to treat aorto-iliac aneurysms endoluminally. Even though stenting is still experimental in some regards, and open surgical reconstruction represents the established standard, it has great therapeutic potential. However, endovascular techniques should neither be rejected nor simply adopted by vascular surgeons but developed further in a team approach with experienced interventional angiologists and radiologists.

Aorta, Abdominal↗
PubMed1995

[Results in stent implants in pelvic arteries: follow-up with color-coded duplex ultrasonography].

Thirty-one patients (26 males, 5 females), treated with percutaneously inserted endoprostheses (stents) in the iliac artery were followed up a mean 1 year (2-60 months) with regard to clinical and non-invasive results, by color duplex ultrasound and (8 cases) angiography. With one exception self-expandable stents (Wallstents) were applied. The indications for stent implantation were PTA-resistant lesions in 78% and treatment of acute complications after PTA in 22%. Primary technical success with an open stent was achieved in all patients. The ankle-arm systolic pressure index (ASPI) increased from mean 0.67 +/- 0.14 to 0.88 +/- 0.17 (p < 0.001). Early stent occlusion occurred in 1 patient (3%), and 9 (24%) further complications (thrombosis, distal embolization, puncture site problems) were treated either by conservative or interventional procedures, and only once by surgical revision. Color duplex ultrasound showed all stents open without stenosis of hemodynamic significance. Angiography demonstrated intimal hyperplasia in 2 patients with stenosis of about 20-25%. At follow-up 61% of the patients were asymptomatic, 32% were improved. Remaining symptoms were due to lesions of the distal arteries and not to obstructions of the stents. Stenting of iliac arteries is a safe and effective treatment for recurrent and/or complex iliac lesions and has become a valuable adjunct in catheter interventions. We conclude that color duplex ultrasound is not only applicable in native arteries but also in stents, and gives reliable results with regard to hemodynamically relevant obstructions.

Aged↗