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Colour Doppler ultrasound in deep venous thrombosis: a comparison with venography.

Colour Doppler ultrasound is a new technical development allowing simultaneous grey scale imaging and a dynamic colour flow vascular image. To date, many real time ultrasonic studies have been assessed in the diagnosis of lower limb venous thrombosis and have been shown to be accurate in the femoral and popliteal segments. A double blind prospective study comparing colour Doppler with contrast venography in the diagnosis of lower limb thrombosis was performed in a group of 40 patients. Of the study group, 26 venograms were negative and 27 ultrasound examinations were negative. Of the 14 positive venograms there was one false negative colour doppler scan which missed a calf and lower popliteal thrombosis. Two cases of isolated calf vein thrombosis were successfully detected by colour Doppler. Overall, the sensitivity and specificity for detection of lower limb venous thrombosis, including calf vein assessment, were 93% and 100% respectively. Colour Doppler is easy to perform; the average scanning time being 15 minutes for complete assessment of a unilateral lower limb venous system. Spontaneous flow is evident in the femoropopliteal segment, whilst proximal calf vein flow can only be appreciated with the aid of distal compression. Eccentric thrombus and partially recanalized thrombus can be shown. Although the number of isolated calf vein thromboses was small, early experience suggests colour Doppler may be useful in the assessment of proximal calf vein patency.

Adult↗

The risk of deep-vein thrombosis after operations on a bloodless lower limb. A venographic study.

In 17% of 40 patients undergoing operation in a bloodless field on the lower limb, thrombosis was diagnosed phlebographically. Phlebography was performed between the second and eighth postoperative day. The incidence of thrombosis in this series was relatively low, considering other reports on postoperative thrombosis and the theoretical dangers of thrombosis involved in the use of a tourniquet. Factors which could explain the relatively low frequency of postoperative thrombosis are discussed.

Adult↗

Prospective randomized trial of warfarin and intermittent pneumatic leg compression as prophylaxis for postoperative deep venous thrombosis in major urological surgery.

Postoperative deep venous thrombosis and pulmonary embolus remain a major source of morbidity and mortality for the urological surgery patient. We report the results of the first 100 patients in a prospective, randomized trial of low dose warfarin and intermittent pneumatic leg compression for deep venous thrombosis prophylaxis. All patients underwent preoperative and postoperative real-time ultrasound imaging and Doppler flow studies of the popliteal, femoral and iliac veins for the evaluation of deep venous thrombosis. Our results indicate that low dose warfarin is as effective as intermittent pneumatic leg compression for prophylaxis of deep venous thrombosis. Low dose warfarin can be used effectively without any significant bleeding complications. We recommend the use of low dose warfarin as an alternative to intermittent pneumatic leg compression for deep venous thrombosis prophylaxis of the urological patient undergoing a major urological operation.

Aged↗

Central venous thrombosis: an early and frequent complication in cancer patients bearing long-term silastic catheter. A prospective study.

Studies on catheter-related central venous thrombosis (CRCVT) have been focused mainly on clinically evident CRCVT due to occlusive thrombi, underestimating therefore the actual thrombosis prevalence. This prospective study was aimed at evaluating prevalence, timing and evolution of thrombosis, and identifying involved veins and risk factors in cancer patients (pts) undergoing percutaneous subclavian central venous catheterization (CVC) for chemotherapy, parenteral nutrition or both. We enrolled 127 consecutive pts requiring partially or totally implanted central venous silastic catheters. The study protocol included peripheral phlebography (P) at day 8, 30 and every two months following CVC and/or when clinically indicated, along with peripheral and pullout P on catheter withdrawal. A quantitative scale was developed to evaluate thrombus grading in subclavian, innominate and cava veins. Age, sex, coagulation profile tumor histotype, metastases, therapy, catheter type, and catheter insertion side were also investigated. Only pts who underwent at least two P were evaluated, and chi 2 test was adopted for statistical analysis. Altogether, 95 pts were evaluable. CRCVT was observed in 63/95 (66%) pts. At day 8, 30 and 105 (representing the median days in which first, second and last P were performed) CRCVT was evidenced in 64%, 65% and 66% of the pts, respectively. Thrombus grading did not differ among first, second and last P. CRCVT was symptomatic in 4/63 (6%) pts. Thrombosis prevalence was higher in subclavian (97%) with respect to innominate (60%) or cava (13%) veins (p < 0.001). Thrombosis was higher in left subclavian catheters (14/16; 87.5%) than in right ones (49/79; 62%), p < 0.01. No associations were established between CRCVT and other investigated parameters. Our data show a very high actual frequency of CRCVT in cancer pts, and emphasize that first days following CVC are at the highest risk for CRCVT development. Based on our results, a study on short-term antithrombotic prophylaxis in cancer pts requiring CVC is warranted. Finally, our data indicate that left subclavian vein catheterization represents a risk factor for CRCVT.

Adolescent↗

[Deep venous thrombosis in an adult with varicella].

INTRODUCTION: Some viral infections are associated with deep venous thrombosis. We report a case of deep venous thrombosis in an adult with varicella. He had neither known predisposing factors for thrombosis nor thrombophilia. EXEGESIS: Transient significant level of antiphospholipid antibodies and lupus circulating anticoagulant were observed. There was no evidence of thrombophilia. Deep venous thrombosis has been mostly associated with varicella in children. A transient protein S deficiency was present in almost all cases, though it was sometimes related to an anti-protein S antibody. This association is exceptional in adults. Some viruses such as herpesvirus and HIV are responsible for endothelium dysfunction, but this is still unclear in the case of varicella-zoster virus. CONCLUSION: In our observation, endothelium activation or antiphospholipid antibodies might be responsible for thrombosis.

Adult↗

Does blood flow accurately predict thrombosis or failure of hemodialysis synthetic grafts? A meta-analysis.

A number of studies have reported that a single low blood flow (Qa) measurement in synthetic hemodialysis grafts predicts thrombosis or failure. In a meta-analysis of these studies, we computed receiver operating characteristic (ROC) curves that evaluated the predictive accuracy of a Qa measurement. The ROC curves plotted sensitivity versus false-positive rate for predicting thrombosis or failure at different Qa thresholds. A perfect predictor has an area under the curve (AUC) of 1.0, whereas a predictor with no discriminative ability has an AUC of 0.5. We identified studies through a literature search and included our own unpublished data. A random-effects model was used to combine the ROC curves from different studies. Of 19 identified studies, 12 were suitable for computing binormal ROC curves (6 predicted thrombosis; 6 predicted failure). The studies measured Qa and then observed outcome during periods of 1.5 to more than 6 months. The combined AUCs from these studies indicate Qa was a relatively poor predictor, with 0.70 +/- 0. 04 (range, 0.61 to 0.84) for thrombosis and 0.76 +/- 0.07 (range, 0. 62 to 0.90) for failure. The wide range of AUCs also shows there was much heterogeneity between studies. We conclude that a single Qa measurement does not appear to have enough accuracy to be a clinically useful predictor of graft thrombosis or failure. Serial Qa measurements and identification of factors that caused heterogeneity between studies may be needed to achieve sufficient accuracy.

Blood Flow Velocity↗

Venous thrombosis and pulmonary embolism. A study of 5039 autopsies.

The frequency and the localisation pattern of venous thrombosis and subsequent pulmonary embolism detected postmortem was studied by reviewing 5039 autopsy records from 1975 through 1980 and from 1987/88 of two university hospitals. The autopsy procedure was identical in both study periods. Thrombosis was documented overall in 34.2% with a slight increase from the first to the second series. Taking in account the cases of pulmonary embolism without detected source, the thrombosis rate was 42.6%. The rate of cases with thrombi in the vena cava superior system almost doubled (1975: 9.2%, 1987/88: 17.0%; p less than 0.05). Regarding the list of thrombus localisations the right internal jugular vein (16.9%) was second only to the left femoral vein (17.8%) in 1987/88. Pulmonary emboli were seen in 1500 of 5039 autopsies (29.8%); in 59.4% the source was found in the lower venous tree, in 12.6% in the upper venous tree. In 28.0% no source could be detected. In these cases we supposed a complete detachment of thrombi from the lower venous tree to be the most likely reason. In 628 of the 1500 cases (42.5%) pulmonary embolism was classified as fatal. Both rates, for total pulmonary embolism and for fatal thrombembolism showed a small, but significant decrease during the study period. In 8.3% (52/628) the source of fatal pulmonary emboli was situated in the upper venous tree including the right heart. This means that 10.2% (52/512) of all cases with isolated thrombosis in the vena cava superior system were associated with fatal pulmonary embolism. Venous thrombosis and pulmonary embolism are still frequent findings at autopsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Autopsy↗

Care of patients with deep venous thrombosis in an academic medical center: limitations and lessons.

PURPOSE: The primary goal of our study was to review the quality of care in patients with deep vein thrombosis,, with emphasis on identifying recurrent and remedial problems. Secondary goals were (1) to evaluate the use of the vascular laboratory and (2) to characterize our patient population with deep vein thrombosis and to identify a subset of patients with uncomplicated deep vein thrombosis who might be candidates for outpatient therapy in the future. METHODS: A retrospective review was performed for all patients with deep vein thrombosis diagnosed with duplex scanning who were treated as inpatients from January 1993 through March 1993. RESULTS: Fifty-four (16%) of 306 duplex scans were positive; 50 patients were treated as inpatients. Forty percent of patients had uncomplicated deep vein thrombosis that was potentially treatable on an outpatient basis. Mean time to obtain a therapeutic partial thromboplastin time was 22 hours (range 4 to 54 hours). Ten (20%) patients had inferior vena cava filters placed. The in-hospital mortality rate was 4%. Management problems occurred in 18 (36%) patients and included difficulty titrating anticoagulation, (10) physician failure to provide treatment after diagnosis, (five) and inappropriate use or complication of inferior vena cava filter placement (three). CONCLUSIONS: Venous duplex examination is liberally but appropriately used. The primary remediable problem resulting in suboptimal management is difficulty titrating anticoagulation; inappropriate placement of inferior vena cava filters and physician failure to provide treatment also occur. In the future a substantial number of patients may be suitable for outpatient therapy.

Academic Medical Centers↗

The treatment of venous thrombosis of the upper and lower limbs with "APSAC" (p-anisoylated streptokinase-plasminogen complex).

APSAC, administered by bolus injection, has been used to treat 28 patients: 14 with ilio-femoral venous thrombosis, 6 with "spontaneous" axillary-subclavian thrombosis and eight with superior vena-caval thrombosis associated with parenteral nutrition catheter. Four of the patients with lower limb deep vein thrombosis (DVT) showed partial lysis whereas the remaining 10 showed no change. Of the patients with upper limb and/or superior caval DVT seven showed complete lysis three showed partial lysis and four showed no benefit. APSAC is an effective treatment of venous thrombosis of the upper limbs.

Adult↗

Symptomatic venous hypertension because of occult iliofemoral deep vein thrombosis: a report of two cases.

Two 25-year-old males with symptomatic venous hypertension (venous claudication, n = 1; swollen leg, n = 1) were evaluated for iliofemoral venous occlusive disease. One patient had a common femoral vein/external iliac vein occlusion with no history of deep vein thrombosis or trauma. The second patient had an acute deep vein thrombosis superimposed on a chronic external iliac vein stenosis. No source of extrinsic venous compression was identified in either patient. Venous reconstruction with vein bypass (patient no. 1) and vein patch angioplasty (patient no. 2) led to resolution of their hypertensive symptoms. Intraoperative examination of the involved vein segments revealed chronic changes consistent with a prior occult deep vein thrombosis in both patients. Occult iliofemoral deep vein thrombosis in young healthy males is rarely seen. The acute deep vein thrombosis may manifest minimal or no symptoms but it can lead to chronic venous occlusive disease and serious post-phlebitic morbidity. In this context, these two cases are discussed with a review of the pertinent literature.

Adult↗

Insensitivity of color Doppler flow imaging for detection of acute calf deep venous thrombosis in asymptomatic postoperative patients.

PURPOSE: Although color Doppler flow imaging (CDFI) has been shown to accurately depict calf vein thrombosis in symptomatic patients, this technique has not been proved accurate for detection of calf vein thrombosis in a population restricted to asymptomatic postoperative patients. PATIENTS AND METHODS: To evaluate the accuracy of CDFI in asymptomatic postoperative patients, both CDFI and contrast venography were performed on 78 limbs of 76 patients without symptoms of deep venous thrombosis (DVT) who had undergone either hip or knee replacement. CDFI and venographic examination were interpreted blindly with respect to the results of the other modality or clinical findings. Venography was the standard for comparison of results. RESULTS: Fifty-six percent of CDFI examinations of the calf vein were technically adequate. The remaining studies were compromised technically by limb swelling and/or obesity. For the technically adequate CDFI studies, calf vein thrombosis was detected in eight of 10 patients. Calculated sensitivity in this cohort was 80%, and specificity was 97%. The sensitivity of CDFI for acute calf DVT in all patients, regardless of image quality, was 42%. CONCLUSION: These observations suggest that state-of-the-art CDFI is not an accurate examination for acute calf vein DVT in asymptomatic postoperative patients. CDFI is associated with a high rate of technically compromised studies and relatively low sensitivity in studies that are deemed technically satisfactory. These observations do not preclude the use of CDFI in postoperative patients for detection of thrombus extension into the popliteal vein or for detecting thrombosis of more proximal lower extremity veins.

Female↗

[Routine nursing measures for thrombosis prevention in a university hospital].

A literature search on the subject of thrombosis prevention showed that there have been changes in preventive nursing measures in the last three decades. Data on preventive measures as actually employed at the different Clinics of the Innsbruck Medical University were gathered with the help of written questionnaires (completed by 192 staff nurses and 111 nursing students) with the aim of instituting improvements in such measures in actual practice. Our investigation showed that 56.9% of the participants did not know what the appropriate time was for discarding graduated elastic compression stockings for antithrombotic prophylaxis; 72.7% reported that they measured patients' legs for proper fit only seldom or not at all. 77.5% said that patients refused to wear the elastic stockings during the night. Only 22.3% reported that the compression device was worn by patients 24 hours a day. 82.5% had not participated in any continuing education programmes on thrombosis prophylaxis in the past five years. According to 42.3% of study participants, nursing measures for thrombosis prevention must be carried out jointly by physician and nurse. Based on this investigation, we have compiled a booklet of guidelines to be used for teaching nursing students and for continuing education of staff nurses, and have raised our internal standards to comply with the state of the art in thrombosis prevention. We plan to investigate antithrombotic measures currently in place in the area of intensive care. It is also planned to invite the opinion of patients on the matter of wearing compression stockings for thrombosis prophylaxis in order to gain some understanding of the reasons why patients refuse to wear them at night.

Adult↗

Vascular surgical society of great britain and ireland: transcranial doppler-directed dextran therapy in the prevention of postoperative carotid thrombosis

BACKGROUND: Evidence suggests that embolization precedes carotid thrombosis, a previously unpredictable event complicating 2-3 per cent of all carotid endarterectomies. It was hypothesized that dextran 40 therapy might prevent progression to complete thrombosis in high-risk patients. METHODS: Between October 1995 and July 1998, 400 consecutive patients were monitored following carotid endarterectomy using transcranial Doppler ultrasonography. Those with sustained embolization (more than 25 in 10 min) or those with emboli that distorted the middle cerebral artery waveform were commenced on an incremental dextran 40 infusion. RESULTS: Two hundred and sixteen patients (54 per cent) had one or more emboli detected (96 per cent within 2 h of flow restoration) but only 15 (4 per cent) required dextran therapy. Embolization ceased in each case although the dextran dose had to be adjusted in four. In one of the latter patients, embolization recurred on day 5 but was again controlled with high-dose dextran. Overall, the death and any stroke rate was 2 per cent and no patient suffered a stroke due to carotid thrombosis. CONCLUSION: A few patients develop sustained embolization following carotid endarterectomy which, in previous studies, has been shown to be highly predictive of carotid thrombosis. The authors' experience to date suggests that dextran can stop this phase of embolization and prevent progression to complete carotid thrombosis. However, the dose of dextran has to be adjusted in 25 per cent of patients (i.e. blind administration of dextran may not be effective) and, very rarely, embolization may recur later.

Journal Article↗

Perioperative topical bovine thrombin exposure is not associated with hemodialysis graft thrombosis.

Arteriovenous (AV) graft use as hemodialysis access remains highly prevalent, with a consequent high thrombosis rate. The magnitude of this problem requires that all potentially modifiable risk factors for graft thrombosis be thoroughly investigated. During graft surgery, topical bovine thrombin is often administered, which can lead to the development of antibovine thrombin antibodies and subsequent hemostatic changes. A recent study correlated the presence of plasma antibovine thrombin antibodies with graft thrombosis in hemodialysis patients. We therefore hypothesized that perioperative topical bovine thrombin exposure would lead to the development of antibovine thrombin antibodies and graft thrombosis. We screened 314 hemodialysis patients and identified 73 patients who had 74 grafts placed for whom complete data on perioperative topical bovine thrombin exposure and subsequent graft outcomes was available. Sixty-one of these patients were available for retrospective measurement of antibovine thrombin antibodies, antihuman thrombin antibodies, and the thrombin activation markers thrombin activatible fibrinolysis inhibitor (TAFI) and thrombin precursor protein (TpP). In these grafts, there was no significant association between topical bovine thrombin exposure and primary assisted patency (P = 0.37). The presence of antibovine thrombin antibodies (P = 0.13), antihuman thrombin antibodies (P = 0.10), and increased TAFI (P = 0.18) were associated with trends toward reduced primary assisted patency which did not reach significance. There was a correlation between antibovine thrombin antibodies and antihuman thrombin antibodies (r = 0.30, P < 0.0001) and between TAFI and TpP trade mark (r = 0.30, P < 0.0001), but no significant correlation between topical bovine thrombin exposure and elevated levels of antibovine thrombin antibodies, antihuman thrombin antibodies, TAFI or TpP trade mark. We conclude that perioperative topical bovine thrombin exposure is not associated with subsequent graft thrombosis.

Aged↗

Effects of clopidogrel, aspirin and combined therapy in a porcine ex vivo model of high-shear induced stent thrombosis.

AIMS: Use of ticlopidine in coronary stenting is limited by delayed onset of action. We studied the effects of clopidogrel, a rapidly acting analog of ticlopidine alone, and in combination with aspirin, in inhibiting stent thrombosis. METHODS: Unpolished nitinol stents were deployed in a porcine ex vivo arteriovenous shunt and exposed to flowing arterial blood at a shear rate of approximately 1500. s-1. Stent thrombus, platelet aggregation and bleeding times were measured at baseline and after treatment. RESULTS: Intravenous clopidogrel produced a rapid (within 30 min) and dose-dependent inhibition of stent thrombosis, with 87% reduction at a dose of 10 mg.kg-1 (P < 0.001). Aspirin alone (10 mg.kg-1) was minimally effective (20% inhibition P > 0.05) in inhibiting stent thrombosis. Combined treatment with clopidogrel and aspirin produced 95-98% inhibition of stent thrombosis, even at low doses of clopidogrel (2.5-5.0 mg.kg-1) (P < 0.0001). At effective doses both clopidogrel and combined therapy produced significant prolongation of bleeding time (P < 0.05) and inhibition of platelet aggregation (P < 0.05). CONCLUSION: Clopidogrel, either alone or combined with aspirin, may have a potential role in preventing stent thrombosis in high-risk clinical situations.

Animals↗

[Out-patient treatment of deep vein thrombosis: management and experience of two vascular care centres in Germany].

BACKGROUND AND OBJECTIVE: In Germany there are still major reservations about using low molecular weight heparin for the treatment of deep vein thrombosis. Based on encouraging international reports, we have been establishing a primarily out-patient management of thrombosis since 1996. In our centres for vascular diseases we tried to evaluate the suitability of such a regimen for the treatment of patients in Germany. PATIENTS AND METHODS: Between January 1996 and October 1999 we evaluated the possibility of an out-patient therapy for all patients with acute deep vein thrombosis who had been referred to our institution. Suitable patients were treated with an initial daily dose of 200 IU Dalteparin per kg body-weight in addition to compression therapy. RESULTS: During this time we treated 587 patients with deep vein thrombosis of the lower extremities (41 % men and 59 % woman with a mean age of 60.3 +/- 13.8 years) of whom 105 were hospitalised. Out-patient therapy was without any complications in 94.2 % of the remaining 482 patients. Overall mortality was 0.4 % (2 patients). The deaths occurred without apparent relationship to the kind of therapy. Progressive thrombus extension occurred in five patients, symptomatic pulmonary embolism in one patient and >>recurrent thromboembolic events<< in nine patients. These results correspond with the good efficacy of Dalteparin as expected from the data in the literature. Severe bleedings were not observed. Three patients experienced mild bleeding. CONCLUSIONS: We conclude from our data that, in accordance with international studies, an out-patient thrombosis management with Dalteparin is efficacious and safe.

Acute Disease↗

[The fate of the patient with deep vein thrombosis].

Late results in 278 consecutive patients with unilateral deep vein thrombosis treated with streptokinase or heparin/dicoumarol were analysed as to mortality rate, recurrent thrombo-embolism and incidence of postthrombotic syndrome (PTS). The five-year mortality rate was three times as high as that of the age-matched population. The overall mortality rate was 16%, more than half the patients dying of tumour, males largely of gastric or bronchial carcinoma, females of urogenital carcinoma. Thrombo-embolism had recurred in 14% of 204 patients who had been re-examined, in 9% thrombosis, in 3% pulmonary embolism, and in 2% both. A PTS without ulcer had developed in 16%, an ulcer in 8%. The PTS incidence correlated with the original extent of the thrombosis: no PTS if the thrombosis had been confined to the lower-leg axis, but 34% after four-level thrombosis. The data confirm the importance of thrombo-embolism prophylaxis, early diagnosis and subsequent treatment with anticoagulants and compression.

Adult↗

Combined use of leg scanning and impedance plethysmography in suspected venous thrombosis. An alternative to venography.

Venography is the standard method for the diagnosis of venous thrombosis but is invasive and may cause discomfort. We evaluated the combination of impedance plethysmography and 125I-fibrinogen leg scanning as an alternative to venography in 200 symptomatic patients. One or both of these less invasive tests was positive in 81 of 86 patients with positive venograms (sensitivity of 94 per cent) and both were negative in 104 of 114 patients with negative venograms (specificity of 91 per cent). These two tests detected all 60 patients with popliteal or more proximal venous thrombosis and 21 of 26 patients with calf-vein thrombosis. In addition, this approach detected 21 of 22 patients with calf-vein thrombosis with symptoms for eight days or less. These results suggest that the combination of these two less invasive tests can be used as an alternative to venography in selected patients with clinically suspected venous thrombosis.

Adolescent↗