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Biomedical subjects

P Mismetti

Publications and source records attributed to P Mismetti.

At least 37 records · Page 2Linked to original sources

[Current indications of cava filters].

Permanent vena cava filters are useful in venous thromboembolism in some rare medical situations (i.e., contra-indication or failure of anticoagulant therapy). Other indications are controversial. Indeed filters increase the risk of recurrence of deep vein thrombosis and also probably the incidence of post-thrombotic syndrome. So filter placement remains a crucial decision, according to each individual case. The operator's choice is of prime importance. When a permanent filter is inserted the use of graded compression stockings and long-term anticoagulant therapy deserves to be considered. In case of transient risk, temporary filters might be an interesting therapeutic approach but their assessment is insufficient in order for them to be currently recommended.

Contraindications↗

Evolution of blood coagulation and fibrinolysis parameters after abrupt versus gradual withdrawal of acenocoumarol in patients with venous thromboembolism: a double-blind randomized study.

A double-blind randomized trial was conducted to research a hypercoagulable state rebound after abrupt versus gradual withdrawal of acenocoumarol, 20 patients were included: 10 in the abrupt withdrawal group (AW) and 10 in the gradual withdrawal group (GW). Between days 1 and 15,F1 + 2 was higher in group AW (P < 0.002). A significant increase of D-dimer with time was found (P < 0.001) without difference between the two groups, tPA and PAI-1 levels remained stable throughout without difference between the two groups. No rebound phenomenon was observed. Four thrombotic recurrences were observed: group AW: 1, group GW: 3 (P = 0.29). There is neither clinical nor biological support for a gradual anticoagulation withdrawal.

Acenocoumarol↗

Symptomatic inferior vena cava filter thrombosis: clinical study of 30 consecutive cases.

Inferior vena cava (IVC) filter thrombosis has not been described as a clinical entity. Thirty patients with IVC percutaneous filter thrombosis were assessed by cavography, computed tomographic (CT) scan and/or duplex ultrasonography. All patients had proximal venous thrombosis when the filter was placed, and the indication for filter placement was a contraindication to anticoagulant therapy in eight patients (27%). Filter thrombosis occurred within 6 months following filter placement in 15 patients (early filter thrombosis group). Among these patients, 10 were not treated with oral anticoagulant, and none of the other five received adjusted anticoagulation. No patients with late filter thrombosis received anticoagulant at the time of the diagnosis. Early filter thrombosis was mainly associated with LGM filters (12 of the 15 cases). Occlusion was revealed by recurrent venous thrombosis in 18 cases. A thrombus above the filter and pulmonary embolism was found in 10 patients (33%). Thrombolytic therapy failed in 5 out of 7 cases, and all but two patients were treated with anticoagulant therapy. In conclusion, early filter thrombosis appears to be due to intracaval extension of deep vein thrombosis, and this emphasizes the need for appropriate anticoagulation. In the case of temporary contraindication to anticoagulation at the time of the filter placement, anticoagulant should be reassessed later.

Adult↗

[Search for the "optimal" dose of antithrombotic agents].

The determination of the "optimal" dose is an essential step in the development of a molecule. In the case of anti-thrombotic agents, the search for this "optimal" dose is based on dose-effect relationships on biological criteria in phase I, and, often, radiological criteria in phase II trials. The main objective of these dose studies is not to directly evaluate the benefit-risk ratio of the molecule under development, but to find the dose which will be tested in phase II to estimate the benefit-risk ratio. Errors of choice of dosage observed at the end of phase III trials may be due to problems of extrapolability of the results of the dose studies due to too strict a selection of subjects included and therefore not representative of the target population of the new treatment or to the use of intermediary criteria for the evaluation of the antithrombotic effect. However, these dosage errors are still mainly due to an inadequate search for the "optimal" dose despite the fact that the ethnical and economic consequences are not negligible.

Anticoagulants↗

Chrono-pharmacological study of once daily curative dose of a low molecular weight heparin (200 IU antiXa/kg of Dalteparin) in ten healthy volunteers.

Low molecular weight heparin (LMWH) is currently prescribed for the treatment of deep vein thrombosis at the dose of 100 IU antiXa/kg twice daily or at a dose of 175 IU antiXa/kg once daily with a similar efficacy. We decided to study the chrono-pharmacology of curative dose of LMWH once daily administrated according to the one previously described with unfractionated heparin (UFH). Ten healthy volunteers participated in an open three-period crossover study according to three 24 h cycles, separated by a wash-out interval lasting 7 days: one control cycle without injection, two cycles with subcutaneous injection of 200 IU antiXa/kg of Dalteparin (Fragmin) at 8 a.m. or at 8 p.m. Parameters of heparin activity were analysed as maximal values and area under the curve. Activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT) and tissue factor pathway inhibitor (TFPI) were higher after 8 p.m. injection than after 8 a.m. injection (p < 0.05) while no chrono-pharmacological variation of anti factor Xa (AXa) activity was observed. Thus the biological anticoagulant effect of 200 IU antiXa/kg of Dalteparin seems to be higher after an evening injection than after a morning injection. A chrono-therapeutic approach with LMWH, as prescribed once daily, deserves further investigation since our results suggest that a preferential injection time may optimise the clinical efficacy of these LMWH.

Adult↗

[Inflammatory pseudotumor of the intestine caused by necrotizing vasculitis in the course of Horton disease].

The authors report a case of giant-cell arteritis involving the digestive tract, revealed by a subocclusive syndrome. It appeared to be an unusual pattern according to the location, the tumour aspect and the histologic appearance of a periarteritis nodosa type. The digestive involvement and the histologic appearance are discussed in a review of the literature, as well as the link with the periarteritis nodosa.

Adrenal Cortex Hormones↗

Pentosan polysulfate-induced thrombocytopenia and thrombosis.

Pentosan polysulfate is a low-molecular-weight sulfated polysaccharide used as an antithrombotic drug. We present two patients who developed thrombocytopenia and venous thrombosis during treatment with pentosan polysulfate. The relationship between pentosan polysulfate and thrombocytopenia is supported by platelet aggregation and serotonin release tests. In the light of the literature and our two cases, it appears that pentosan polysulfate alone as standard heparin and low-molecular-weight heparin can induce thrombocytopenia and thrombosis. Platelet counts should therefore be periodically monitored during pentosan polysulfate treatment. In the case of pentosan polysulfate-induced thrombocytopenia, it seems that heparin or low-molecular-weight heparin should not be instituted during the acute phase even if platelet aggregation studies are negative, because of their low sensitivity. After remission of thrombocytopenia, whether or not glycosaminoglycans can be reinstituted, at least temporarily, after antibody had disappeared is still an open question.

Aged↗

Fibrinolysis and elastic compression: no fibrinolytic effect of elastic compression in healthy volunteers.

The local and systemic fibrinolytic response to the placing of elastic compression in healthy volunteers was studied to determine whether this method of preventing venous thromboembolism has any profibrinolytic effect, as previously demonstrated with intermittent pneumatic compression. Variations in the major parameters of fibrinolysis (euglobulin lysis time, t-PA antigen, PAI-1 antigen, PAI-1 activity) were studied in an open randomized cross-over study in 21 healthy volunteers, in which three types of treatment were tested for periods of 24 h each (without elastic compression, elastic compression of an upper limb, elastic compression of the lower limbs). Four blood samples were taken from the upper limb during each period (at 08:00 h, 10:00 h, 18:00 h, 08:00 h on the following day). The placing of elastic compression did not cause any statistically significant change in the four parameters tested between the three types of treatment. In contrast, circadian rhythm was confirmed for all the fibrinolytic factors studied with a minimal fibrinolytic activity in the morning and a maximal activity in the evening. Elastic compression does not seem to have any profibrinolytic effect in healthy volunteers but other studies are needed in patients before a definitive conclusion can be reached.

Adolescent↗

Dosing time optimizes sustained-release ketoprofen treatment of osteoarthritis.

A double-blind randomized parallel-group trial was undertaken to evaluate the influence of the dosing time of sustained-release ketoprofen (SRK) on its acceptability and efficacy. The SRK was prescribed for 2 weeks (200 mg once a day) to 117 outpatients with osteoarthritis of the knee and/or hip. One group received SRK in the morning (at 8 a.m.) and the other group in the evening (at 8 p.m.). The principal aim of the trial concerned the acceptability, whereas efficacy was its secondary aim. The principal trial criterion was defined as the number of spontaneous recordings of adverse effects. Results showed clearly that the acceptability of SRK in the SRK morning group was worse than that in the evening group (39% of patients with one or more adverse effects in the SRK morning group versus 19% in the evening group; p = 0.019). It is important to stress the difference concerning the number of adverse effects (48 for SRK morning group versus 23 for SRK evening group; p = 0.0234). The analgesic efficacy seemed to be similar, but one criterion was statistically significant: The duration of analgesic efficacy was more important for the SRK evening group than for the morning group (9.37 and 5.47 h, respectively; p = 0.001). To increase its acceptability, evening administration of SRK seems to be preferred over morning administration in osteoarthritis. However, other trials of the same type, assessing other antiinflammatory agents, are necessary before a general extrapolation of such results can be undertaken.

Adult↗

[Phlebitis following travel].

The term of economy class syndrome has been used to describe the deep vein thrombosis which may follow air travel. The mechanisms suggested for this include tendency to clot formation in the legs secondary to the reduced venous return induced by the sitting position with direct compression of popliteal and femoral veins, and secondary to dehydration and haemo-concentration. However, these conditions are also observed with others means of transport. We describe 16 patients with deep vein thrombosis following travel by bus, car, truck and train. These 16 patients represent 3.4 percent of 465 patients with thromboembolism managed over a 52-month period in our department. All but one patients had one or more risk factors for deep vein thrombosis. The mean duration of the trip was 14.2 hours and the first symptom occurred less than a week after the journey in 75 percent of the patients. These first symptoms suggested deep vein thrombosis in 8, pulmonary embolism in 5, and deep vein thrombosis with pulmonary embolism in 3 patients. Regular non alcoholic drinks and regular walks seem to be sufficient to prevent deep vein thrombosis in the great majority of travellers. However, low dose heparin on a temporary basis or elastic stockings could be considered in high risk subjects.

Adult↗

Acceptability and efficacy of two associations of paracetamol with a central analgesic (dextropropoxyphene or codeine): comparison in osteoarthritis.

A double-blind randomized parallel group trial was undertaken to compare the acceptability and efficacy of 2 forms of analgesic treatment, DI-Antalvic (Houde Laboratories, Puteaux, France) (30 mg dextropropoxyphene and 400 mg paracetamol per capsule) and Efferalgan-Codeine (UPSA Laboratories, Rueil Malmaison, France) (30 mg codeine and 500 mg paracetamol per tablet) prescribed for 1 week at doses of 6 capsules/day and 6 tablets/day, respectively, in 141 outpatients with active osteoarthritis of the knee or hip. The principal aim of the trial was concerned with acceptability, with efficacy as its secondary aim. The principal trial criterion was defined as overall assessment of acceptability by the patient at the end of the trial (success or failure) or by treatment dropouts because of an adverse effect (failure). Comparability of the groups was confirmed before any treatment regarding the physical characteristics of the patients, characteristics of osteoarthritis, and the initial level of pain and functional consequences of pain. Results show that the analgesic efficacy of the treatment was similar, but that the acceptability of Efferalgan-Codeine was significantly worse than that of DI-Antalvic: 53% failure with Efferalgan-Codeine versus 29% failure with DI-Antalvic (P = .005). Other trials of the same type would seem necessary (comparison of lower doses, other types of pain) before being able to generally extrapolate such findings.

Acetaminophen↗

[Chronopharmacology of fractionated heparin (nadroparin) administrated by subcutaneous route at prophylactic doses in healthy volunteers].

This study evaluated the effect of injection time on pharmacodynamic of a single subcutaneous bolus of nadroparine (7500 anti-Xa IC U) evaluated by anti-Xa activity (Hepaclot and Heptest) and by activated partial thromboplastin time (APTT by auto PTT reagent). 10 healthy male volunteers were studied at 4 different 24 hours periods with 4 different injection times (6 am, 12 am, 6 pm, 12 pm) and with a one week wash-out period between each period. No chronopharmacological variation of the anti-Xa activity evaluated by Hepaclot was found. However the anti-Xa activity evaluated by Heptest was higher at the sixth hour after 12 am injection (p = 0.0022). No difference on APTT values was observed whatever the injection time. So the injection time of nadroparine has a weak influence on anti-Xa activity and no effect on APTT; Before to conclude on the lack of chronopharmacological effect of nadroparine, it seems necessary to evaluate such a possibility with higher dosage, with sick and older subjects.

Adult↗

Circadian dynamics of coagulation and chronopathology of cardiovascular and cerebrovascular events. Future therapeutic implications for the treatment of these disorders?

Arterial thromboembolic disorders are the leading cause of death in most of the advanced nations. The study of epidemiologic relationship of these disorders to biological rhythms may lead to a better understanding and perhaps a better treatment. Chronoepidemiologic studies demonstrated a morning peak for arterial thromboembolic disorders (cerebral and myocardial infarctions) and sudden cardiac deaths. These variations might be explained partially by circadian variations in hemostasis. Indeed chronophysiologic studies have shown that hemostatic variables follow circadian rhythms. The level of platelet aggregation and that of blood coagulation have been found to be increased in the morning whereas fibrinolytic activity is lower at this time of the day. The facts suggest a chronotherapeutic approach in thromboembolic disorders.

Animals↗

[Current indications for inferior vena cava interruption].

Clinical indications of vena cava interruption are reviewed. During the last few years pulmonary embolism frequency remained high and many new percutaneous vena caval filters became available. These facts probably explain the increasing use of these filters reaching about 10,000 filters each year in France. Existing data show that: embolic risk with antithrombotic agents is less than 5%, probably not far greater than embolic risk with cava filters (about 2%); complications encountered with the filters are caval thrombosis in 8%, and more or less than 4% other major complications; there is no controlled study comparing antithrombotic treatment associated with caval filters to antithrombotic treatment alone; there is no controlled study comparing new cava filters among them or to the Greenfield filter; economical implications of caval filters are mostly unknown. The only admitted indications of vena cava interruption, in case of proximal venous thrombosis, are contraindications to anticoagulation. In other situations no data allow to recommend a cava filter; indication will be discussed on a case by case basis. Prospective controlled studies are greatly encouraged.

Heparin↗

Good clinical practices in phase I studies.

In France, official guidelines for good clinical practices in clinical trials were issued in 1987. In December 1988, a law was passed that fixed the requirements for carrying out experiments in healthy subjects. It will be completed by official guidelines for the structures in which experiments on healthy subjects (and patients as well, when the investigation would not benefit the health of the patients) may be conducted. Hence a battery of recent legal instructions precisely state what good clinical practices are in the setting of phase I studies. Of particular importance are: subject recruitment and selection methods and procedures; specific competence of the investigator, in particular to interpret the pre-trial data; necessary and sufficient facilities to guarantee the subjects' safety; careful quality control to check all laboratory procedures; necessity of written standard operating procedures.

Drug Evaluation↗