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Biomedical subjects

A Bollinger

Publications and source records attributed to A Bollinger.

At least 37 records · Page 2Linked to original sources

Prospective 12-year follow-up study of clinical and hemodynamic sequelae after deep vein thrombosis in low-risk patients (Zürich study).

BACKGROUND: No prospective study of the long-term sequelae of more than 10 years after acute deep vein thrombosis exists so far. Therefore, 58 low-risk patients with DVT were included in a prospective study to evaluate the natural history of postthrombotic syndrome. METHODS AND RESULTS: Clinical and hemodynamic examinations were performed at the time of admission; after 3, 6, and 12 months; after the 2nd, 3rd, 4th, 5th years; and finally after the 12th year. All patients received heparin initially and oral anticoagulants subsequently. After 12 years, 64% of the patients exhibited normal findings. Mild skin changes were found in 28%, marked trophic changes in 5%, and only one venous ulcer occurred. Regular use of compression stockings was reported by 54% of the patients with multilevel thrombosis. Although mean maximum venous outflow was significantly reduced from the acute event to 12 years later (P<.003) compared with the contralateral leg, a significant (P<.05) improvement was observed 6 months later. Recanalization of calf vein thrombosis was detected by Doppler sonography after 3 months. Sixty-four percent of the multilevel thromboses were recanalized completely or in part after 1 year; in 69%, valvular incompetence was found. CONCLUSIONS: In contrast to earlier reports, this prospective study up to 12 years after deep vein thrombosis demonstrates a low incidence of postthrombotic syndrome by administration of oral anticoagulants and regular compression therapy. However, the adverse clinical event rate (mortality 14%) and a recurrence rate of 24% show that the prognosis after deep vein thrombosis does not appear favorable even in low-risk patients.

Administration, Oral↗

Microinjection technique for pharmacological evaluation of microvascular permeability in human skin.

A new technique which combines skin microinjection of minute amounts of drugs (0.5 microliter) and measurement of capillary permeability by intravital fluorescence videomicroscopy and densitometry is introduced. Glass micropipettes with a tip diameter of 7-9 microns are inserted by a micromanipulator into the stratum papillare containing the capillary loops and used for microinjection by microsyringe and special dispenser. Transcapillary diffusion of sodium fluorescein applied by intravenous bolus injection is visualised by fluorescence videomicroscopy and stored on videotape. Perivascular fluorescent light intensity (FLI) is measured in arbitrary units (AU) by videodensitometry around the site of microinjection during playback of the videotapes. The method was tested by microinjection of 0.5 microliter histamine (1% solution) at the distal tibial plateau. Mean FLI values representing microvascular permeability were 2186 AU 10 min after microinjection of histamine, 420 AU after physiologic saline and 1228 AU after histamine combined with oral intake of 20 mg cetirizine. Cetirizine significantly reduced (P < 0.01) the increased permeability induced by histamine. However, the mean values after injection of the H1-blocker were still significantly enhanced (P < 0.01) when compared to the mean values observed after injection of physiologic saline solution, which provoked only minor microtrauma. The technique offers new scope for pharmacological testing in man.

Adult↗

Flow velocity of single lymphatic capillaries in human skin.

The purpose of this study was to investigate the previously unknown flow velocity in single lymphatic capillaries of humans in the supine position. Fifteen healthy subjects (10 women and 5 men; mean age 35.8 +/- 13.1 yr) were studied. Ten microliters of fluorescein isothiocyanate-dextran (150,000 mol wt) were injected into the subepidermal layer of the foot dorsum. The filling of the microlymphatics from the resulting depot was visualized by fluorescence video microscopy and stored on videotape. Flow velocity in the microlymphatics was determined on the video screen by direct measurement of the advancement of dyed lymph during a given time. The following median velocities were obtained: 0.51 mm/s (0.27 and 0.61 mm/s for lower and upper quartiles, respectively) for velocity during initial network filling and 9.7 microns/s (6.9 and 14.2 microns/s for lower and upper quartiles, respectively) for resting velocity at the end of the filling period. Mean lymphatic capillary diameter was 54.8 +/- 8.2 microns, and mean network extension was 8.3 +/- 3.2 mm. The high filling velocities are probably due to increased interstitial pressure and volume caused by dye microinjection, whereas the values measured during the end of network filling seem to approach resting flow velocities.

Adult↗

Microvascular changes in arterial occlusive disease: target for pharmacotherapy.

The main techniques which have been used to study skin microcirculation in patients with peripheral arterial occlusive disease include intravital microscopy with and without the use of fluorescent dyes, laser Doppler fluxmetry and transcutaneous oximetry. In patients with severe ischaemia (rest pain or incipient gangrene) the number of perfused skin capillaries is reduced. Parallel to the decreased number of microvessels containing blood, transcutaneous oxygen tension is low or even approaches the zero level. The tendency to oedema formation is documented by increased leakage of intravenously injected sodium fluorescein at the capillary apex of foot skin ('candlelight phenomenon'). Laser Doppler flux at rest may still be within the normal range even in advanced disease, since the sample volume of these instruments also contains non-nutritive shunt vessels. However, reactive hyperaemia after arterial occlusion is decreased and delayed in peripheral ischaemia. Whereas rhythmic low-frequency vasomotion is significantly enhanced in patients with intermittent claudication, vasoparalysis with no flux fluctuations prevails in patients with critical ischaemia.

Arterial Occlusive Diseases↗

[Color duplex ultrasonography in the diagnosis of deficient perforating veins in comparison to cw-Doppler ultrasonography and clinical examination].

The study was conducted to investigate the accuracy and agreement between clinical examination, cw-Doppler ultrasound and color-duplex sonography in diagnosing incompetent perforating veins. Nineteen patients with chronic venous insufficiency (CVI) were examined clinically, by hand-held cw-Doppler ultrasound in combination with tourniquet compression and color-coded duplex sonography CDS. The accuracy of the clinical examination and the diagnosis of ICPV by cw-Doppler were surprisingly low. The specificity was 15% and sensitivity 29%, when CDS was taken as gold standard. Furthermore the results show clearly that the application of a tourniquet cannot provide reliable results. It is concluded that in patients with CVI clinical and cw-Doppler examinations are not sufficient for an accurate diagnosis of incompetent perforating veins. Color-duplex provides a new noninvasive approach for accurate anatomical and functional diagnosis, which is of great importance prior to surgical interventions and/or sclerotherapy.

Adult↗

[Significance of arterial anastomoses of the distal calf and proximal foot for compensation of peripheral arterial occlusive disease].

The vascular anatomy of the distal calf and proximal foot was studied in 16 preparations obtained by corrosion. Arterial anastomoses between the different vessels are frequently observed and were also detected by digital subtraction arteriography in 14 patients with peripheral arterial occlusive disease. The comparison between anatomy and arteriography revealed that performed anastomoses in the malleolar and proximal foot region are important for compensating crural arterial occlusions. The Ramus communicans posterior, the Ramus perforans of the fibular artery and the Rete calcaneare play an important role. Whereas in other vascular territories collaterals dominate for compensation of occlusions performed anastomoses are of crucial importance at the malleolus.

Aged↗

[Rhythmic lymph extravasation from a lymph fistula].

A 66-year-old woman with a chronic traumatic lymph fistula is described. Using the almost atraumatic fluorescence micro-lymphography the fistula could be precisely localized within the ulcer. Lymph flow from deep channels was rhythmic. This previously unknown phenomenon of rhythmic retrograde flow in a lymphatic fistula is probably due to the activity of contractile segments of lymph collectors and an important factor for the non-healing of ulcers.

Aged↗

Effects of monoionic and nonionic radiographic contrast media on cutaneous microcirculation in patients with peripheral arterial occlusive disease.

The purpose of the study was to compare the in vivo effects of two low-osmolar radiographic contrast media, a monoionic (sodium/-meglumine ioxaglate, Hexabrix) and a non-ionic one (iopromide, Ultravist 300) on the cutaneous microcirculation in patients with peripheral arterial occlusive disease in a prospective randomised double-blind study. In 20 patients with peripheral arterial occlusive disease scheduled for percutaneous transluminal angioplasty skin microcirculation was assessed by laser Doppler fluxmetry and transcutaneous oxygen tension measurements at the foot dorsum for continuous recordings of the cutaneous microvascular perfusion and skin oxygenation. Before angioplasty 10 ml nondiluted contrast medium was injected intraarterially and the acute effect on transcutaneous oxygen tension and laser Doppler flux was registered. Mean laser Doppler flux and oxygen tension were evaluated initially, after arterial puncture and after contrast medium injection. In addition, flux motion was analysed with respect to frequency and amplitudes changes. No significant changes in laser Doppler flux and fluxmotion patterns were found between both groups after contrast medium injection. However, mean transcutaneous oxygen tension of the patients receiving monoionic ioxaglate dropped significantly (P = 0.01). The differences of both contrast media on red blood cell aggregation shown in vitro do not correlate to intravital microcirculatory measurements in patients with arterial occlusive disease of the lower limb. Microvascular skin blood flow and flux motion at the foot in these patients do not change significantly after intraarterial injection of ioxaglate and iopromide. However, oxygen supply of the skin is transient impaired after interarterial injection of the anionic contrast agent ioxaglate, which was not associated with clinical symptoms.

Aged↗

Microvascular changes in chronic venous insufficiency--a review.

Chronic venous insufficiency is the result of an impairment of the main venous conduits, causing microvascular changes. The driving force responsible for the alterations in the microcirculation is probably the intermittently raised pressure propagated from the deep system into the capillaries. The capillaries are dilated, elongated and tortuous and their endothelium is injured (irregular luminal surface, increased cytopempsis, dilated interendothelial spaces). Through the latter an increased extravasation can be observed, leading to an enlarged pericapillary space, oedema in the interstitial tissue and to the clinical finding of swelling. Haemoglobin from extravasated erythrocytes and erythrocyte fragments in the pericapillary space is degraded to haemosiderin which is responsible for hyperpigmentation. Microthrombosis in the capillaries causes microinfarction and micronecrosis. Skin areas with severe microangiopathy have reduced numbers of perfused nutritional capillaries and are characterized by a low transcutaneous (tc) PO2. The increased blood flow in the deeper skin layers does not contribute to nutrition of the superficial skin layers. The microvascular ischaemia is patchy and appears to be the main factor determining trophic changes and venous ulceration. The process of microinfarction and micronecrosis is followed by the formation of a granulation tissue, proliferation of capillaries and fibroblasts and finally wound healing by formation of scar tissue destroying the microlymphatic network. Clinically this process leads to lipodermatosclerosis, atrophy and in its most extreme form to ulceration where the compensating mechanisms are no longer able to repair the damage.

Capillary Permeability↗

Simultaneous measurement of digital artery and skin perfusion pressure by the laser Doppler technique in healthy controls and patients with peripheral arterial occlusive disease.

OBJECTIVE: To assess feasibility of a new technique for simultaneous measurement of digital artery and skin perfusion pressure at the same digit using the laser Doppler method and to measure the pressure gradient between the two vessel compartments in controls and patients with peripheral arterial occlusive disease. DESIGN: A pressure cuff wrapped around the basis of the toe and connected to a Statham transducer is covered by a special plastic capsule. A hole at the distal end of the capsule permits positioning of a laser Doppler probe at the pulp. A second laser Doppler probe is placed on the skin beneath the pressure cuff. Reappearance of pulsatile flux during cuff pressure release detected by the two laser Doppler probes indicated digital artery pressure and skin perfusion pressure on the corresponding pressure curve. Results in patients with intermittent claudication were compared to results of a group of normal controls. SETTING: University Hospital, Zürich, Switzerland. MATERIALS: Eleven healthy volunteers and 14 patients with intermittent claudication due to peripheral arterial occlusive disease were studied. CHIEF OUTCOME MEASURES: Digital artery pressure (DAP), skin perfusion pressure (SPP) and pressure gradient between DAP and SPP. MAIN RESULTS: Significantly lower mean DAP (95.8 +/- 23.2 mmHg vs. 49.8 +/- 20.4 mmHg; p < 0.01) and mean SPP (81.4 +/- 18.8 mmHg vs. 38.4 +/- 21.7 mmHg; p < 0.01) were observed in the patients. Mean pressure gradients and ratios between DAP and SPP did not differ significantly between the two groups. There was a linear correlation between DAP and SPP (r = 0.82, p < 0.01). CONCLUSION: The laser Doppler method provides the possibility to measure digital artery and skin perfusion pressure simultaneously at the same digit in an easy and non-invasive way. Pressure gradients between DAP and SPP are similar in controls and patients with claudication.

Adult↗

A new therapeutic approach to popliteal artery entrapment syndrome (PAES).

OBJECTIVES: An alternative therapeutic approach to popliteal artery entrapment syndrome (PAES) with vascular complications. MATERIALS: Three male patients (16, 42 and 68 years) with thrombotic and/or embolic obstructions of popliteal or crural vessels as a consequence of popliteal entrapment syndrome. METHODS: Combined catheter treatment consisting of percutaneous transluminal thrombembolectomy (PTEE), local thrombolysis (LTL) and percutaneous transluminal dilatation (PTA) was performed for thrombotic and embolic obstructions of popliteal or crural vessels. The aberrant tendomuscular structures were surgically corrected at a later date. RESULTS: After the procedure systolic ankle/arm pressure ratios in the three patients improved from 0.66 to 1.13, 0.57 to 1.07 and 0.46 to 1.10. Twelve, 8 and 4 months later the patients were asymptomatic. None of the patients showed popliteal artery compression during plantar flexion on Duplex scanning. CONCLUSIONS: This new therapeutic approach avoids direct vascular surgery with bypass or patch implantation in patients with PAES who are often young. The long term results remain to be evaluated.

Adolescent↗

Intravital capillaroscopy in patients with chronic venous insufficiency and lymphoedema: relevance to Daflon 500 mg.

Microangiopathy of chronic venous insufficiency is characterized by elongated, dilated and coiled skin capillaries, which are surrounded by an enlarged pericapillary space (halo). Reduction of capillary number and even areas devoid of microvessels (atrophie blanche) are common in severe chronic venous insufficiency associated with focal microvascular ischaemia (decreased transcutaneous oxygen tension). The superficial network of skin lymphatic capillaries is obliterated in part. Oedema formation results from increased permeability of blood capillaries (enhanced transcapillary diffusion of sodium fluorescein) and deficient lymphatic drainage of interstitial fluid.

Diosmin↗

Management of congenital angiodysplasia of the lower limb: magnetic resonance imaging and angiography versus conventional angiography.

The purpose of the study was to compare magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) with conventional angiography in distinguishing congenital angiodysplasia amenable to radical cure from that in which only palliation is feasible and to design a rational pre-operative work-up in those patients undergoing an interventional procedure. Axial T1, T2 weighted spin-echo and contrast-enhanced 3D SPGR sequences were performed in 13 patients with angiodysplasia, followed by time-of-flight MRA. The results were compared with conventional arteriography and venography. Dysplasia was arteriovenous with microshunts in nine cases and purely venous in the remaining four. MRI was the best method for assessing the extent of malformation and involvement of anatomical structures. MR arteriography and MR venography were inferior to conventional techniques. It is concluded that MRI is valuable in distinguishing patients amenable to radical cure from those in whom only palliation is feasible. Pre-operatively, conventional arteriography and venography remain mandatory.

Adolescent↗

Reversal of atherosclerotic obstructions by percutaneous transluminal angioplasty raises high-density lipoprotein cholesterol.

Variation of high-density lipoprotein cholesterol (HDL) levels in man show a strong inverse relationship to the incidence of atherosclerotic vascular disease. Conversely, effects of atherosclerosis and ischemia on lipoprotein metabolism are unclear. We investigated 41 patients, 10 women and 31 men, undergoing percutaneous transluminal angioplasty by measuring fasting lipoprotein cholesterol including high-density lipoprotein subfraction analysis before and one as well as 12 weeks after the procedure. Successful reopening of a haemodynamically significant iliac, femoral or popliteal obstruction was achieved in all patients. A highly significant (p < 0.001) increase of HDL cholesterol from 1.10 +/- 0.05 to 1.31 +/- 0.06 mmol/l was revealed 12 weeks later. This was due to a significant (p < 0.001) increase in HDL3 cholesterol by 26%, whereas HDL2 cholesterol did not change significantly. We conclude that HDL cholesterol levels increase after recanalization of a significant atherosclerotic obstruction which may be a direct effect of reperfusion or an indirect effect due to an increase in exercise tolerance.

Adult↗