[Isoprostanes: new markers of oxidative stress in human diseases]

BACKGROUND

Most of the traditional methods used to assess oxidative stress in clinical setting are non specific, unreliable or inaccurate. Recently, a novel family of prostaglandin F2 isomers, called F2-isoprostanes, produced in vivo by a free radical peroxidation of arachidonic acid, has been described. These compounds may produce physiological or pathological effects due to their ability to alter smooth muscle and platelet functions. The quantification of the two major isoforms (isoprostaglandin F2 alpha type-III and VI) in biological fluids and tissues as markers of lipid peroxidation appears to be an important advance in our ability to explore the role of free radicals in the pathogenesis of human disease.

CLINICAL DATA

Urinary excretion of F2-isoprostanes is correlated with age, indicating increased oxidative stress during the normal aging process. High F2-isoprostanes concentration has been described in diseases such as ischemic heart disease, diabetes, Alzheimer's disease and hepatic cirrhosis. The correlation of F2-isoprostane concentrations and human diseases severity in hepatic cirrhosis, cardiac failure and diabetes suggest that these compounds may be of interest as predictive markers.

PERSPECTIVES

Preliminary studies suggest the use of F2-isoprostanes as prognosis markers. In addition, F2-isoprostanes quantification offers promising potential as intermediate endpoints for clinical studies of antioxidant therapies.

[Isoprostanes: new markers of oxidative stress. Fundamental and clinical aspects]

A novel family of prostaglandin F2 isomers, called F2-isoprostanes, produced in large quantities in vivo by a free radical peroxidation of arachidonic acid, has recently been described. The quantification of the two major isoforms (isoprostaglandin F2alpha type-III and VI) in biological fluids and tissues as markers of lipid peroxidation appears to be an important advance in our ability to explore the role of free radicals in the pathogenesis of human disease. In addition, F2-isoporstanes quantification seems promising as intermediate endpoints for clinical studies of antioxidant therapies.

Thromboxane A(2) modulates cyclic AMP relaxation and production in human internal mammary artery

Two forms of thromboxane A(2) (TP) receptors, TPalpha and TPbeta receptors, have recently been cloned. These receptors regulate adenylate cyclase activity in two opposite ways: TPalpha receptors activate, whereas TPbeta receptors inhibit adenylate cyclase and cAMP generation. The aim of this study was to examine the effects of the thromboxane A(2) analogue, U46619 (9,11-dideoxy-9alpha,11 alpha-methanoepoxy-prostaglandin F(2alpha)), on forskolin-induced relaxation and cAMP accumulation in human internal mammary artery (IMA) and saphenous vein (SV). In organ baths, IMA rings precontracted with U46619 (3.10(-9) and 3.10(-8) M) were less sensitive to forskolin than rings precontracted with methoxamine (3. 10(-6) M). In contrast, the sensitivity to forskolin was similar in SV rings contracted with the same concentrations of these agonists. U46619 reduced significantly the ten-fold increase in cAMP induced by forskolin in IMA but not in SV rings. Sensitivity and maximal relaxation in response to sodium nitroprusside were not altered in either IMA or SV. In summary, stimulation of TP receptors with the thromboxane A(2) analogue, U46619, inhibited the cAMP pathway of relaxation through the inhibition of cAMP synthesis in human IMA but not in SV. It is suggested that thromboxane A(2) may play a role in the control of muscle tone in IMA both by its potent contractile effect and by its inhibitory effect on the cAMP pathway of relaxation.

Are isoprostanes a clinical marker for antioxidant drug investigation?

Numerous pathological conditions are suspected to involve free radical production as part of their pathogenic process. Therefore, a pharmacological control of oxidative stress could probably benefit many vascular, inflammatory or degenerative diseases. However, the development of antioxidant drugs and their clinical evaluation are limited by the absence of an accurate, reliable and easy-to-handle marker of tissue oxidative events. Isoprostanes (isoPs), a prostaglandin-related series of metabolites, are emerging as major candidates for clinical measurement of oxidative stress. They are chemically stable products of lipid peroxidation, formed in cellular membranes and subsequently released and excreted in the urine. Many recent clinical studies have reported that urinary and plasma levels of isoPs (in particular the iPF2alpha-III isomer also called 8-epi-PGF2alpha) are increased in clinical conditions where oxidative stress is suspected to play a pathogenic role. Moreover, isoPs have been detected in tissue extracts from atherosclerotic plaques and Alzheimer patients brain tissue. Finally, antioxidant treatments such as vitamin E supplementation appear to reduce isoPs levels in biological fluids of treated patients. These preliminary observations argue for a further investigation of isoPs as a practical pharmacodynamic endpoint for the clinical evaluation of antioxidant therapies.

[In vitro study of of the effects of cysteinyl leukotrienes on human vascular preparations]

Leukotrienes are 5-lipoxygenase-derived arachidonic acid metabolites. In addition to their bronchoconstrictor effects, leukotrienes are also important modulators of the vascular tone which may exert paradoxical effects. Indeed, depending on the vascular tone (in either the basal or norepinephrine-precontracted state), leukotrienes are capable of inducing either contraction or relaxation. These paradoxical effects of leukotrienes depend on the vascular bed and the species investigated. Since urinary LTE4 excretion is increased in various cardiovascular diseases, including arterial pulmonary hypertension or cardiac ischaemia, the study of the effects of leukotrienes on human vascular preparations is of interest. This article reviews the in vitro evidence linking cysteinyl leukotrienes to the modulation of the vascular tone on human vascular preparations.

[Compression of the renal artery by a musculo-tendinous band: an unrecognised cause of renovascular hypertension]

Stenosis of a renal artery by extrinsic compression is an uncommon cause of renovascular hypertension. In rare cases, this compression is due to the presence of fibres from the diaphragm or the psoas muscle. This aetiology should be considered when renal artery stenosis is observed in a young hypertensive patient without cardiovascular risk factors. Spiral CT scan is particularly useful for studying the relationship between the diaphragm and arterial structures. Once the diagnosis has been made, the treatment is surgical section of the fibrous tissues responsible for the compression.

Vasorelaxant actions of enoximone, dobutamine, and the combination on human arterial coronary bypass grafts

Enoximone (a type III-selective phosphodiesterase inhibitor) and dobutamine (a beta-receptor agonist) are positive inotropic drugs frequently used in the postoperative management of coronary bypass surgery. The purpose of this study was to characterize their relaxant effects on the human internal mammary artery (IMA) and the gastroepiploic artery (GEA) and to test the hypothesis that their combination may have greater than additive relaxant effects. In organ baths, the relaxant effects of enoximone and dobutamine were tested on rings of IMA (n = 86) precontracted with U46619 (a thromboxane A2 mimetic), norepinephrine (NE), or KCl. The relaxant effects of dobutamine and enoximone also were tested on rings of GEA (n = 42) precontracted with U46619 and NE. The effect of the combination of enoximone and dobutamine were tested on rings of IMA (n = 24) precontracted with U46619 or NE. With respect to maximal relaxations induced by papaverine (10(-4) M), enoximone (< or =10(-3) M) caused full relaxations of IMA precontracted with NE, U46619, or KCI. Dobutamine (< or =10(-3) M) caused full relaxations of IMA precontracted with NE or KCI but only 46% (95% CI, 27-65) relaxation in the rings precontracted with U46619. Similar patterns of relaxation were observed in GEA rings, with dobutamine inducing partial relaxation in GEA precontracted with U46619. The pD2 values of enoximone and dobutamine were both significantly lower in segments precontracted with U46619. The in vitro threshold relaxant concentrations were in the upper limits or over the range of therapeutic plasma concentrations. The relaxant effect of the combination was significantly more important than the theoretic additive effect in IMA contracted with U46619 or NE. Enoximone and dobutamine are potent in vitro vasodilators but exert weak relaxant effects in IMA and GEA at concentrations in the therapeutic range. There is, however, a greater than additive vasorelaxant effect of the combination, suggesting that the vasorelaxant effect of the combination, in addition to the additive inotropic effect, may be beneficial to patients undergoing coronary bypass grafting.

Reactivity of the Human Internal Mammary Artery and the Gastroepiploic Artery to Constrictor Substances

The internal mammary artery (IMA) and the gastroepiploic artery (GEA) are frequently used to construct coronary artery bypass grafts. In order to determine and to compare their contractile properties, we studied the effects of constricting agents which are liberated or infused during coronary bypass surgery. IMA and GEA were arranged as ring segments and suspended in organ baths at optimal stretch using a normalization procedure. Concentration-contraction curves to angiotensin II, norepinephrine, U-46619, endothelin-1, leukotriene C(4) and KCl were performed. The sensitivity (pD(2)) of GEA and IMA to all the agents did not differ. However, GEA developed stronger maximal contraction force than IMA to angiotensin II (P < 0.001), norepinephrine (P < 0.05), U-46619 (P = 0.06), endothelin-1 (P < 0.01), and KCl (P < 0.01), whereas leukotriene C(4) did not induce a significant contraction on GEA and IMA. The higher contractility of GEA may explain that it is more prone to spasm than IMA in the clinical setting. This study reinforces IMA as a first-choice conduit for coronary artery bypass and emphasizes the need for antispastic drugs particularly when GEA is used as bypass vessel.http://link.springer-ny.com/link/service/journals/00547/bibs/8n4p187.html</hea

Functional comparison of the human isolated femoral artery, internal mammary artery, gastroepiploic artery, and saphenous vein

Human femoral, internal mammary, and gastroepiploic arteries and saphenous veins are used as bypass grafts for coronary surgery or for reconstruction in arterial occlusive disease. We have characterized the contractile responses of these vessels to various agents that are liberated during cardiac or vascular surgery. In organ baths, U46619 (a stable thromboxane A2 mimetic), norepinephrine, endothelin-1, angiotensin II, and KCl caused concentration-dependent contractions in all vessels tested. Leukotriene C4 did not induce any contraction in the arteries, whereas a contraction was obtained in the saphenous vein rings. U46619 induced the most powerful contraction in all vessels tested. The pD2 values for each agent did not differ among the different vessels. When responses were expressed as a percentage of KCl-induced contraction, the contraction of endothelin-1 (151+/-5%) and leukotriene C4 (43+/-5%) was more significant on saphenous veins than on arteries. In conclusion, thromboxane A2 appears to be the most potent endogenous constricting agent on different human vascular beds. Our second finding is that saphenous veins are more sensitive to contract to leukotriene C4 and endothelin-1 than arteries. These properties may influence early and (or) long-term vein graft patency.

Functional assessment of rat aorta after cold storage in different media

Cold storage is frequently used to store isolated blood vessels for a limited period of time. However preservation of vascular smooth muscle and endothelial functions is time and medium-dependent. The present study was designed to compare the reactivity of rat aorta before and after cold storage for 24 and 48 h in one of four different solutions consisting of Hepes-buffered Krebs solution, Belzer solution, Krebs solution, and Eurocollins solution. Smooth muscle and endothelial functions of the rat aorta were assessed using in vitro isometric tension measurement. The results obtained for vessels preserved for 24 and 48 h were compared with those for vessels studied immediately after harvesting. Sensitivity and maximum contraction to KCl and norepinephrine were not altered in rat aorta preserved up to 48 h in Hepes-Krebs and Belzer solutions. In contrast, the amplitude of contraction elicited by KCl was significantly reduced by 50% and 77% in aorta stored for 24 and 48 h in Krebs solution and by 77% and 96% in those stored in Eurocollins solutions. Similarly, the maximal contraction elicited by norepinephrine was significantly reduced by 60% and 45% in arteries stored for 24 and 48 h in Krebs solution and by 34% and 86% in those stored in Eurocollins solution. In contrast, cold storage in the different media did not alter the relaxations elicited by sodium nitroprusside and forskolin. The endothelium-dependent relaxations in response to acetylcholine were not statistically modified after preservation up to 48 h in Hepes-Krebs solution. In contrast, the maximal relaxations to acetylcholine were significantly decreased after storage for 24 and 48 h in Belzer, Krebs and Eurocollins solutions. These results suggest that among the four media studied, Hepes-Krebs solution is the most suitable medium for the storage of blood vessels under hypothermic conditions.

[Endothelin-1 and cardiovascular diseases]

INTRODUCTION

Endothelins are peptides released from endothelial cells. According to both their structure and receptor affinity, three isoforms may be identified. Endothelin-1 is secreted abluminally by endothelial cells, and binds ETA and ETB2 receptors expressed on vascular smooth muscle cells, and ETB1 expressed on endothelial cells. ETA and ETB2 receptors stimulation induces smooth muscle contraction and proliferation, whereas ETB1 receptors stimulation induces relaxation.

CURRENT KNOWLEDGE AND KEY POINTS

Endothelin-1 plays an important role in maintaining peripheral vascular tone and systemic blood pressure. It is recognized to have a role in various diseases associated with vasoconstriction and vascular hypertrophy.

FUTURE PROSPECTS AND PROJECTS

Recent development of endothelin receptor antagonists seems promising for the treatment of heart failure and systemic hypertension, with interesting results obtained from short-term clinical trials. However, better evaluation of these drugs requires further long-term studies regarding not only the above mentioned diseases but also ischemic heart disease or pulmonary hypertension. Endothelin antagonists are therefore new therapeutic agents able to inhibit a vasoconstricting system that has been recently discovered. Results of ongoing clinical studies are awaited with interest.

Effect of topical vasodilators on gastroepiploic artery graft

BACKGROUND

Mobilization of the gastroepiploic artery (GEA) often results in a vasospasm with reduction of early graft flow. In order to prevent or suppress this highly reactive artery's spasm, we have compared the effect of 4 vasodilators, used in external application to prepare the GEA graft, prior to myocardial revascularization.

METHODS

WE performed a double-blind clinical study to compare the effects of external application of vasodilators on gastroepiploic artery grafts. Fifty patients, whose gastroepiploic artery was used for coronary artery bypass grafting, were randomized into 5 groups of 10 patients. Gastroepiploic artery free flow and hemodynamic measurements were evaluated immediately after harvesting, before any pharmacological manipulation, and 10 minutes after the topical application of vasodilators, respectively: papaverine, linsidomine, nicardipine, glyceryl trinitrate, and normal saline solution.

RESULTS

A significant increase in free flow occurred in all groups except for the normal saline solution group with measurements from 26.1+/-3.6 mL/min to 26.4+/-6.5 mL/min; p = 0.9. The most important increase in flow before and after local application occurred with glyceryl trinitrate and papaverine: from 25.5+/-2 mL/min to 50+/-6.1 mL/min (p < or = 0.01) and from 36.8+/-3.2 mL/min to 62+/-7.8 mL/min (p < 0.01) respectively. Nicardipine and linsidomine produced a less significant increase in flow: from 33.1+/-3.6 mL/min to 47.7+/-8.9 mL/min (p < 0.05) and from 28+/-3.8 mL/min to 39.8+/-7.5 mL/min (p < 0.05) respectively. When comparing percentage of flow increase, glyceryl trinitrate appeared to be significantly more efficient than nicardipine and linsidomine (p < 0.01 versus both groups). Although papaverine was more efficient than nicardipine and linsidomine, it did not reach statistical significance.

CONCLUSIONS

During intraoperative preparation of the GEA graft, glyceryl trinitrate and papaverine to a lesser extent, used as topical vasodilators, appear to be more efficient in external application to increase the free flow of the GEA.

Early development of deep-vein thrombosis following hip fracture surgery: the role of venous wall thickening detected by B-mode ultrasonography

Deep-vein thrombosis (DVT) remains the most frequent complication following hip surgery. This study was designed in order to evaluate the development of DVT after hip fracture surgery, and to determine if venous wall thickening detected before surgery predisposes patients to postoperative DVT. Systematic ultrasound examinations were performed on 100 consecutive patients undergoing hip fracture surgery on the day preceding the operation, and then postoperatively on days 2, 5 and 10. A total of 12 proximal, 28 distal deep-vein and four saphenous vein thromboses were detected. Of the DVT, 19 (43%) were detected at day 2. Five out of eight patients with venous wall thickening had a previous history of DVT. Venous wall thickening was positively correlated with proximal DVT development (62.5% versus 8% incidence in the group of patients with and without venous wall thickening respectively; p<0.001, relative risk = 7.8). This study highlights the high frequency of early major thromboembolic events following hip fracture surgery. It is considered that patients with a previous history of venous thromboembolic disease should undergo B-mode ultrasonographic examination before hip fracture surgery. Patients in whom venous wall thickening is detected should have repeated postoperative ultrasonographic examinations enabling early detection of DVT.

[Systemic manifestations and development of GPIIbIIIa antibodies in the course of staphylococcal endocarditis. Report of a case]

Immunological complications of staphylococcal endocarditis are rare but represent a serious event in this condition. The authors report the case of acute tricuspid valve endocarditis in a 38 year old drug addict. The diagnosis was suggested by the presentation of bilateral bacterial lung abscesses with a murmur of tricuspid regurgitation, and confirmed by transthoracic and transoesophageal echocardiography. Bacteriological cultures isolated a methicillin-sensitive staphylococcal aureus. The outcome was complicated by a nephrotic syndrome associated with a glomerulonephritis by deposition of immune complexes and an autoimmune thrombocytopaenic purpura due to acquired anti-glycoprotein IIb IIIa antibodies. Antibiotic therapy led to cure without sequellae of the endocarditis, the nephrotic syndrome and the thrombocytopaenia. This case illustrates the risk of immunological complications during acute staphylococcal tricuspid valve endocarditis and also illustrates the possibility of a favourable outcome with antibiotic therapy alone. However, the potential severity of these complications indicates the need for early diagnosis and strict surveillance of this condition.

Functional assessment of human femoral arteries after cryopreservation

PURPOSE

An established method of cryostorage that might preserve the vascular and endothelial responses of human femoral arteries (HFAs) to be transplanted as allografts was studied.

METHODS

HFAs were harvested from multiorgan donors and stored at 4 degrees C in Belzer solution before cryostorage. One hundred eleven HFA rings were isolated and randomly assigned to 1 control group of unfrozen HFAs and 2 groups of HFAs cryopreserved for 7 and 30 days, respectively. Cryopreservation was performed in Elohes solution containing dimethyl sulfoxide (1.8 mmol/L), and the rate of cooling was 1.6 degrees C/min, until -141 degrees C was reached. The contractile and relaxant responses of unfrozen and frozen/thawed arteries were assessed in organ bath by measurement of isometric force generated by the HFAs.

RESULTS

After thawing, the maximal contractile responses to all the contracting agonists tested (KCl, U46619 [a thromboxane A2-mimetic], norepinephrine, serotonin, and endothelin-1) were in the range of 7% to 34% of the responses in unfrozen HFAs. The endothelium-independent relaxant responses to forskolin and verapamil were weakly altered, whereas the endothelium-independent relaxant responses to sodium nitroprusside were markedly reduced. Cryostorage of HFAs also resulted in a loss of the endothelium-dependent relaxant response to acetylcholine. The vascular and endothelial responses were similarly altered in the HFAs cryopreserved for 7 and 30 days.

CONCLUSION

The cryopreservation method used provided a limited preservation of HFAs contractility, a good preservation of the endothelium-independent relaxant responses, but no apparent preservation of the endothelium-dependent relaxation. It is possible that further refinements of the cryopreservation protocol, such as a slower rate of cooling and a more controlled stepwise addition of dimethyl sulfoxide, might allow better post-thaw functional recovery of HFAs.

[Deep venous thrombosis and severe burns]

Deep venous thrombosis (DVT) is a frequent and potentially serious complication in severely burned patients. We report the case of a burned patient (40% of total body surface burned), who had right femoral deep venous thrombosis and severe pulmonary embolism, although a prophylaxis was conducted with low molecular weight heparin, graduated compression stockings and rotating bed. This case shows that DVT early diagnosis and prophylaxis is difficult in severely burned patients. Systematic screening of DVT by duplex scan is possible only for femoral veins, which renders duplex scan more suitable for femoral catheter follow up than for systematic DVT screening. Computed tomography venography seems to be a valuable tool in the diagnosis of proximal thrombosis. Prophylaxis is best achieved with the use of preventive low molecular weight heparins, graduated compression stockings, and early mobilisation when possible. However, the place of low molecular weight heparins at high doses and external pneumatic calf compression needs to be evaluated by prospective studies.

Glibenclamide inhibits thromboxane A2-induced contraction in human internal mammary artery and saphenous vein

Glibenclamide, like other hypoglycemic sulfonylurea derivatives, is a potent blocker of ATP-regulated K+ channels. In addition, it is reported to inhibit prostanoid-induced contractions of isolated vascular smooth muscle from different animal species. We investigated the effect of glibenclamide on the thromboxane A2-mimetic U-46619 (9,11-dideoxy-9alpha,11alpha-methanoepoxy-prostaglandin F2alpha)-induced contractions in human isolated internal mammary arteries and saphenous veins. In the two vascular preparations, glibenclamide (3, 10 and 30 microM) caused a concentration-dependent shift to the right of the U-46619 contraction-response curve with a reduction, at the highest concentrations, in the maximal responses. This inhibitory effect appears selective for thromboxane A2-induced contractions since glibenclamide (30 microM) did not alter the contraction of internal mammary arteries in response to norepinephrine and of saphenous veins in response to 5-hydroxytryptamine (5-HT) and endothelin-1. However, glibenclamide reduced the endothelin-1-induced contraction in internal mammary arteries. The endothelin-1-induced contractions were similarly inhibited by GR 32191 ([1R-[1alpha(Z),2beta,3beta,5alpha]]-(+)-7-[5-([1,1'-b iphenyl]-4-ylmethoxy)-3-hydroxy-2-(1-piperidinyl)cyclopentyl]-4-++ +heptonoic acid, a thromboxane A2 receptor antagonist. These results suggest that glibenclamide also reduced the endothelin-1-induced contractions by inhibiting a thromboxane A2 receptor-mediated component of the contraction elicited by this peptide. In conclusion, glibenclamide clearly appears to exert a specific inhibitory influence on prostanoid-induced contractions in human internal mammary arteries and saphenous veins.

Effect of low-dose positive inotropic drugs on human internal mammary artery flow

BACKGROUND

Dobutamine (a beta-receptor agonist), enoximone (a type III selective phosphodiesterase inhibitor), and epinephrine (an alpha- and beta-mimetic) frequently are used in the perioperative management of patients undergoing coronary artery bypass grafting.

METHODS

We performed a double-blind clinical study to compare the effects on internal mammary artery free flow of low doses of these three positive inotropic drugs. Thirty patients in whom the left internal mammary artery was used for coronary artery bypass grafting were randomized into three groups. Internal mammary artery free flow and hemodynamic measurements were evaluated before and 10 minutes after the intravenous infusion of dobutamine (3 microg x kg(-1) x min(-1)), enoximone (200 microg/kg), or epinephrine (0.05 microg x kg(-1) x min(-1)).

RESULTS

A significant increase in free flow occurred only in the dobutamine group (33 +/- 7.5 and 42.2 +/- 7.9 mL/min before and after drug infusion, respectively; p = 0.013). Comparison of the increase in flow between the groups, however, showed no difference. These drugs, at doses designed to produce a positive inotropic effect, caused little increase in the free flow of the internal mammary artery.

CONCLUSIONS

The use of dobutamine, enoximone, and epinephrine as low-dose positive inotropic treatments in the perioperative and postoperative periods of coronary artery bypass grafting should depend on their positive inotropic effects rather than their vasodilative effects on the arterial grafts.

[Myocardial localization of malignant non-Hodgkin lymphoma responsive to chemotherapy]

Cardiac malignant non-hodgkinian lymphoma, which is usually asymptomatic, is observed in 15 to 25% of autopsy cases of this condition. The authors report an unusual case of myocardial lymphoma diagnosed during pulmonary oedema. Echocardiography showed left ventricular hypertrophy with increased echogenicity of the myocardial walls and marked decrease in left ventricular ejection fraction. Myocardial biopsy confirmed the diagnosis of a high grade malignant lymphoma. The disease responded to chemotherapy. Early diagnosis of myocardial involvement of a lymphoma, presenting with non-specific electrocardiographic changes, requires investigation by histological study of a myocardial biopsy. This invasive technique is justified because of its therapeutic implications.

[Non-invasive management of a serious acute pulmonary embolism]

Prompt diagnosis of a large pulmonary embolus is essential in order to initiate appropriate treatment early. We report a case of a large pulmonary embolus in which management was aided solely by noninvasive investigations. Transthoracic echocardiogram showed elevated right heart pressures which together with the patient symptoms suggested a major pulmonary embolus. Spiral computed tomography of the chest confirmed the diagnosis. The source of the embolus was shown by echodoppler. This case illustrates that a diagnosis of a major pulmonary embolus can be made using noninvasive techniques. Pulmonary angiography should be reserved for those rare cases in which diagnostic uncertainty remains rather than being used as a routine examination prior to consideration of therapeutic decision.

Pulmonary embolus as a complication of femoral venous catheter removal

The case of a 31 year old woman who developed asymptomatic pulmonary emboli after removal of a femoral venous catheter is reported. A deep venous thrombus had previously been shown to be associated with the catheter. Therefore it is argued that care should be taken when removing femoral lines especially in patients at high risk of thrombosis and that femoral venous duplex scan may be warranted prior to line removal in these high risk patients.

[Short-term change in sural venous thrombosis in patients in surgical intensive care when anticoagulants are contraindicated]

Venous thrombo-embolic disease in neurosurgical and surgical intensive care units is a frequent disorder (between 4.3 and 43 per cent of patients according to studies). The treatment is often difficult. We carried out a retrospective study from January 1994 to September 1995 of 57 patients in neurosurgical and surgical intensive care who developed thrombosis of a sural vein and in whom anticoagulant at therapeutic doses was contraindicated. After a median follow up 14 days echography showed proximal extension of the thrombosis in 4 patients and distal extension in 3 others. Five cases of pulmonary embolism occurred during the follow up period, one of which led to death. No complications (pulmonary embolism or proximal extension of venous thrombosis) occurred in those patients receiving heparin at prophylactic doses (0/11 versus 8/46 in the non-heparin group; p = 0.13). No case of pulmonary embolus occurred in those patients with partial or complete regression of the thrombosis (0/21 versus 5/36 in the group with stable or extending thrombi, p = 0,05). Echographic monitoring enabled therapeutic modification in 5 cases. These results indicate that sural venous thrombosis in the context of neurosurgical and surgical intensive care is a potentially grave situation and that the prescription of anticoagulant therapy even at preventive dose should always be considered. Further, we propose regular echographic monitoring until the patient is mobile.