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Biomedical subjects

C Diehm

Publications and source records attributed to C Diehm.

At least 73 records · Page 4Linked to original sources

Intravascular ultrasound (IVUS) in patients with peripheral arterial occlusive disease (PAOD).

The new method of intravascular ultrasound (IVUS) permits an exact documentation of the pathomorphology of diseased arteries in a two-dimensional cross section image. Exact quantification of the vessel transverse diameters is achiveable. The different ultrasonic properties of fat, connective tissue and calcified tissue allow evaluation of intimal plaque composition. Thrombotic arterial occlusions can be detected. First experiences with IVUS prove, that this method is clearly superior to contrast arteriography and transcutaneous ultrasound, in terms of characterization and quantification of the extent of vessel wall disorders. Distinct structures, such as dissecting membranes or intimal flaps, which may escape arteriographic detection, are clearly visualized by IVUS. False adjustment of the physical parameters of the ultrasonic beam and non coaxial orientation of the ultrasound catheter within the vessel lead to false quantification of the transverse vessel diameters and to over- or underestimation of the echodensity and as a consequence of the intimal plaque composition. Simultaneous imaging of neighbouring arteries, veins or arterial branches allow longitudinal orientation within the vessel. Exact orientation however is only provided by simultaneous fluoroscopy. The present study demonstrates the value of IVUS as a guiding method of transcutaneous interventional procedures. The advantage could be an optimal selection of the recanalizing technique, appropriate to the arterial lesion. The result of interventional therapy can be documented immediately. Furthermore specific injuries of the vessel wall, leading to additional interventions and influencing short and long-term prognosis, can be imaged with high accuracy.

Angioplasty, Balloon↗

Medical edema protection--clinical benefit in patients with chronic deep vein incompetence. A placebo controlled double blind study.

In a randomized placebo controlled parallel double blind study on 40 patients suffering from venous edema in chronic deep vein incompetence, the edema-reducing effect of horse chestnut seed extract vs. placebo, being the main test variable, was demonstrated by hydroplethysmography to be statistically significant. In addition, measurements of leg volume under aggravated conditions (edema provocation) were conducted, which yielded the same results. Additional measurements of leg circumference tendentially confirm the demonstrated clinical efficacy of verum, as is true for phlebody-namometric measurements (pressure at rest, minimum pressure, replenishment time) as well. By measuring the leg volume before and after edema provocation, it could be shown that the clinical benefit for the patient is present in all everyday situations (in movement as well as on sitting or standing). Treatment with an edema protective agent of the horse chestnut seed extract type is thus a useful adjunct to compression therapy. The tested preparation were well tolerated.

Administration, Oral↗

Formation of 13,14-dihydro-prostaglandin E1 during intravenous infusions of prostaglandin E1 in patients with peripheral arterial occlusive disease.

Formation of 13,14-dihydro-prostaglandin (PG) E1 during intravenous infusions of PGE1 in patients with peripheral arterial occlusive disease was investigated. Using both high performance liquid chromatography (h.p.l.c.) combined with radioimmunoassay and gas chromatography/triple stage quadrupole mass spectrometry (GC/MS/MS) basal levels of 13,14-dihydro-PGE1 were found to be close to or below the detection limits of the assay methods. Levels of the PGE1 metabolite increased significantly during the infusion periods and decreased after their end. Since 13,14-dihydro-PGE1, in contrast to its precursors 15-keto-PGE1 and 15-keto-13,14-dihydro-PGE1, is biologically active, its formation could contribute to the beneficial effects of PGE1 administered intravenously in patients with peripheral arterial occlusive disease.

Alprostadil↗

Fibrinolytic therapy of deep vein thrombosis with continuous intravenous infusion of a recombinant tissue plasminogen activator.

Recombinant human rt-PA was administered to 22 patients with deep vein thrombosis at a dosage of 30 to 120 mg/day (0.5 to 1.76 mg/kg body weight/24 hr) over 2 to 10 days. rt-PA induced phlebographically documented substantial recanalization in 18 of 21 patients. The lowest dose of 0.5 mg/kg/24 hr tested here was thrombolytically effective, whereas a dose of 0.95 mg/kg/24 hours and more led to hemorrhagic complications and premature discontinuation of therapy in four of six patients. Blood clotting analysis did not reveal any substantial decrease in fibrinogen concentrations, whereas the euglobulin clot lysis time and thromboelastography demonstrated a systemic fibrinolytic effect. Therapy with rt-PA can thus be considered as an alternative and effective method of therapy in treatment of deep vein thrombosis. The results of this study show that even a dosage of lower than 0.5 mg/kg/24 hr might prove to be effective. Further studies would be required to show whether the fibrin specificity of rt-PA leads to a superiority of this fibrinolytic substance over the conventional thrombolytic agents, streptokinase and urokinase.

Blood Coagulation Tests↗

Periodic variations in skin perfusion in full-term and preterm neonates using laser Doppler technique.

In 37 full-term and preterm infants periodic oscillations of skin blood flux were studied by means of laser Doppler technique during the first week of life. The development of rhythmic oscillations of skin blood flux was similar in all infants. On the first postnatal day rhythmic oscillations were present in the heel skin of all full-term and preterm infants, but were rarely observed in the back and thigh skin. These flux motion patterns were not influenced by small changes in skin temperature. On day 4 rhythmic oscillations became predominant in all body regions. The oscillation frequencies of blood flux in the back, thigh and heel skin of full-term neonates reached the lower range of adult values at the end of the first postnatal week, whereas the oscillation frequencies in the preterm infants were still below the range of full-term neonates.

Back↗

[Antihypertensive therapy in arterial occlusive disease].

Patients with hypertension requiring therapy frequently present with concurrent peripheral vascular disease (PVD). This situation must be taken into account for an optimum antihypertensive treatment. In general, in patients with PVD only a cautious and gradual lowering of the blood pressure is recommended, since the decrease in poststenotic perfusion pressure may accentuate the symptoms of occlusive disease. In intermittent claudication--the most frequent manifestation of occlusive disease beta--receptor blockers today are no longer considered to be contraindicated. In the presence of critical ischemia of the legs (pain at rest and/or necroses) beta blockers should only be given with extreme caution. The agents of choice are calcium antagonists, ACE -inhibitors as well as alpha blockers and some newer vasodilating substances (e.g. Carvedilol). Conventional diuretics show disadvantages. An slightly elevated blood pressure in critical leg ischemia helps to improve the poststenotic perfusion of the affected limb. Antihypertensive treatment should not be instituted in patients whose systolic blood pressure is lower than 160 mmHg.

Adrenergic beta-Antagonists↗

[Effect of intra-arterial and intravenous PGE1 infusions on transcutaneous oxygen pressure in patients with critical ischemia of the extremities].

In a randomized cross-over study 20 patients with peripheral arterial occlusive disease stage IV according to Fontaine received one i.a. infusion of 10 micrograms PGE1 in 25 ml saline over 30 min and one i.v. infusion of 40 micrograms PGE1 in 125 ml saline over 60 min. Transcutaneous PO2 was measured continuously (44 degrees C) on the forefoot and dorsum of the foot of the affected leg as well as on the forefoot of the contralateral limb. During i.a. infusion tcPO2 decreased by 73% on the forefoot combined with pain in the infused leg in 8 patients, whereas i.v. infusion induced a 83.1% increase in tcPO2. All in all i.v. PGE1 infusion resulted in a more pronounced increase of tcPO2 without causing side effects.

Alprostadil↗