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Background: To evaluate the prevalence of thrombosis risk factors in a group of patients undergoing venous duplex scanning (VDS) and to design a risk factor stratification model with the ability to improve the diagnostic yield of VDS., Methods: Risk factor assessment and VDS were performed on 1,000 patients with clinically suspected lower extremity deep vein thrombosis (DVT) and patients were divided into two groups based upon the outcome of their scan: those with and those without confirmed DVT. Univariate and multivariate logistic regression analyses were performed in order to determine the significance of each risk factor in relation to having a confirmed DVT., Results: There were 181 patients (18.1%) with confirmed DVT. A prior history of DVT/pulmonary embolism, malignancy, prior immobilization, and age over 70 were the most important risk factors associated with having a DVT confirmed on VDS. A novel risk factor stratification model was created utilizing the odds ratios of those factors found to be significant and the prevalence of DVT was found to be 92.4% in the high risk category, 11.5% in the moderate risk category, and 3.2% in the low risk category using this model., Conclusions: Venous duplex scanning is established as the screening test of choice when one suspects the diagnosis of DVT despite the significant cost of performing and interpreting the test. We suggest that a better clinical model utilizing risk factor assessment may be the key to increasing the yield rate and cost-effectiveness of VDS by excluding low-risk patients from undergoing unnecessary testing.

Purpose: The purpose of this study was to assess the rate of postoperative deep vein thrombosis (DVT) as a function of oral anticoagulation therapy after total hip replacement surgery., Methods: A total of 125 patients completed the study. All the patients received sequential gradient pneumatic compression over elastic stockings until hospital discharge. In addition, all the patients underwent postoperative heparin therapy followed by oral warfarin therapy, adjusted in dose to maintain a goal international normalized ratio (INR) level of 2.0 to 3.0. Warfarin therapy and compression stockings were continued for 1 month after surgery. Bilateral duplex scanning was performed 1 and 4 weeks after surgery to assess the rate of DVT., Results: Nineteen of the 125 patients had DVT develop (15.2%). Of those thromboses, six (31.6%) and 13 (68%) were detected 1 week and 1 month after surgery, respectively. The rate of proximal DVT was 2.4% (3 of 125) 1 week after surgery and rose to 8.2% (10 of 122) 1 month after surgery. Most DVT cases (64%; 12 of 19) were asymptomatic. The patients in whom DVT developed had significantly lower INR values during the second to fourth postoperative weeks than did those patients without thrombosis, and no differences in INR values were found during the first postoperative week., Conclusion: The risk of the development of DVT extends beyond hospital discharge in patients who undergo total hip replacement, despite a regimen of prolonged oral anticoagulation therapy. This is particularly true in patients whose INR values did not reach therapeutic range during the first postoperative month. Therefore, thrombosis prophylaxis regimens on the basis of the administration of warfarin should try to maintain INR values within therapeutic range during the entire first postoperative month to minimize the incidence of DVT.

Objective: The purpose of this study was to assess the rate of deep vein thrombosis (DVT) resolution and DVT outcomes as functions of the level of oral anticoagulation therapy achieved with warfarin., Methods: In 33 consecutive patients, a series of 35 limbs with acute symptomatic DVT was followed throughout 1 year of anticoagulation therapy. All the patients underwent 5 days of intravenous unfractionated sodium heparin therapy that was adjusted in dose to prolong the activated thromboplastin time to 2.0 to 2.5 times the control. In addition, warfarin was administered for a period of 6 months, with a target international normalized ratio (INR) between 2.0 and 3.0. All the patients underwent venous duplex scanning and physical examination at the time of diagnosis and at 1 week, 1 month, 3 months, 6 months, and 1 year., Results: At the end of the 1-year study period, the rate of complete DVT resolution was 68%. The median INR values in patients with complete DVT resolution were significantly higher than those of patients with incomplete DVT resolution after 1, 3, and 6 months of treatment with warfarin. In addition, the proportion of patients with INR values below therapeutic range was significantly higher in patients with incomplete DVT resolution than in patients with complete DVT resolution after 1, 3, and 6 months of treatment with warfarin. The presence of occlusive thrombi was associated with incomplete DVT resolution. Of the patients with occlusive thrombi, 62% had chronic venous insufficiency symptoms develop, whereas only 11% of the patients with nonocclusive thrombi (P =.003) had these symptoms develop., Conclusion: Despite 6 months of oral anticoagulant therapy, almost one third of thrombi did not resolve completely. The INR values were significantly higher in those patients with complete DVT resolution. These results suggest that the maintenance of an INR level between 2.0 and 3.0 throughout oral anticoagulation therapy will minimize the rate of incomplete DVT resolution.

Successful and cost-effective prophylaxis against venous thromboembolism (VTE) depends on the availability of safe and effective antithrombotic methods, and the ability to match these to patients according to their level of thromboembolic risk. The last 20 years have seen significant developments in methods of thromboprophylaxis but, despite use of the best available methods, VTE still occurs in a significant proportion of patients. Efforts are now focused both on developing more effective pharmacological and physical methods, and improving assessment of thromboembolic risk in clinical practice, with the goal of avoiding unnecessary prophylaxis in low-risk patients and providing enhanced protection to high-risk patients. Factors known to exert a direct effect on thromboembolic risk include previous VTE, advancing age, surgery, malignancy, immobility, and the presence of thrombophilic states. Other less well-defined risk factors include obesity, pregnancy, and leg varicosities. Various risk assessment models (RAMs) have been devised based on these factors, but most of the resulting risk assessment formulae, some of them based on laboratory test results, have been too complicated to gain acceptance in routine clinical practice. Reflecting the need to refine the use of thromboprophylaxis in clinical practice, a number of RAMs have been developed recently, based on epidemiological evidence. Some models include specific recommendations for prophylaxis, based on evidence from randomized, controlled trials.

Purpose: The purpose of this article was to assess a number of hematologic and fibrinolytic assays at the time of diagnosis of deep vein thrombosis (DVT) and at several intervals over a period of 6 months afterward and to correlate these results with the results of serial duplex scanning., Methods: Thirty-five patients (average age 61, range 18 to 82) with acute symptomatic DVT confirmed by duplex scanning were included. On diagnosis, blood was drawn, and plasma levels of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor (PAI), D-dimer (DD), and tissue factor pathway inhibitor (TFPI) were determined. Duplex scanning and all laboratory assays were repeated 1 week, 1 month, 3 months, and 6 months thereafter., Results: The rate of DVT complete resolution 6 months after diagnosis was 57%. Whereas plasma levels of PAI were similar throughout the 6-month follow-up period, t-PA increased significantly 1 week after diagnosis and decreased thereafter. Both DD and TFPI levels decreased significantly after diagnosis compared with presentation values. Comparing these assay levels between patients with complete resolution versus partial or no resolution, PAI levels were significantly higher during the first week in patients with poor outcome. Plasma levels of t-PA were higher in cases with good outcome, and DD levels were higher in patients with poor outcome. TFPI levels were similar in both outcome groups., Conclusions: Patients with complete DVT resolution on duplex scanning at 6 months had significantly lower levels of PAI on presentation and after 1 week than did those with incomplete lysis. Although differences were not significant, t-PA levels were higher and DD lower in patients with good outcome. Our results suggest that certain plasma fibrinolytic assays might correlate with the outcome of DVT, as assessed by duplex ultrasonography.

Purpose: The purpose of this study was to assess the effects of the passive 45-degree reverse Trendelenburg position and graduated compression stockings (GCS) on plasma tissue factor pathway inhibitor (TFPI) and endothelin-1 levels in a group of volunteers., Methods: Ten healthy subjects lay on an examining table for 30 minutes while baseline measurements were made. The table was then tilted to a 45-degree upright position for 60 minutes, and measurements were repeated. On a different day, subjects were tilted again, but on this occasion they wore thigh-length GCS. Blood was drawn before and 60 minutes after tilting during both sessions, and plasma TFPI and endothelin-1 were obtained. Cross-sectional areas of the calf medial gastrocnemius vein, before and after tilting, were measured by a duplex scanner., Results: Upright tilting induced a significant dilation of the medial gastrocnemius veins that was partially corrected by the use of elastic stockings. Similarly, endothelin-1 levels significantly increased after tilting. The use of GCS did not modify these differences. On the other hand, although TFPI levels were not affected by tilting without stockings, they were significantly elevated after tilting when GCS were used., Conclusions: Upright passive tilting induces significant dilation of the deep calf veins and is associated with a significant increase in plasma levels of endothelin-1, whereas TFPI levels remain unchanged. The use of elastic stockings reduces the degree of calf distention but does not prevent an increase in endothelin-1. TFPI levels are significantly increased after tilting when GCS are used. This might represent a previously unknown mechanism of action of elastic stockings with interesting potential for deep vein thrombosis prophylaxis. More studies are warranted in a larger series to confirm these results.

Purpose: The purpose of this study was to evaluate the rate of resolution of deep vein thrombosis (DVT) in the leg, by means of duplex imaging, in patients with symptoms during a 6-month period after initial diagnosis., Methods: Seventy-three limbs in 69 patients with acute DVT diagnosed by duplex imaging received conventional heparin and warfarin treatment and underwent subsequent duplex studies 1, 4, 12, and 24 weeks after the initial diagnosis. The objectives of the study were to document (1) the rate or complete resolution of DVT, (2) the proportion of unstable, floating thrombi, and (3) the development of chronic damage as a result of vessel wall scarring., Results: The rate of normalization of DVT 6 months after diagnosis was 78% in the common femoral vein, 70% in the superficial femoral vein, 75% in the popliteal vein, and 70% in the calf veins examined at the scheduled intervals. Twenty-six percent of thrombi were considered unstable on the baseline examination. The average number of days necessary for these thrombi to become stable was 10.7 days. Damage to the vessel wall or valves was documented in 44% of the patients., Conclusions: Rates of resolution of DVT were similar for the different veins of the leg studied. There was a high proportion of unstable thrombi, which present a high potential risk of embolization. Serial duplex scanning after DVT renders important information with regard to thrombus resolution, propagation, and attachment to the vein wall.

The knowledge of these sources of error together with strict methodology assure reliable results and avoid what some authors consider limitations of the test. These so-called limitations are actually due to incomplete information or insufficient experience. It is our opinion that the key for success when using TEG is to use the test in those cases for which it has been indicated. Also, the fact that TEG is a global test of coagulation should be kept in mind and therefore the need for additional hemostatic tests should be evaluated when applicable (Fig.3). According to this review, the established applications of TEG are as follows: (1) detection of hypercoagulable states, particularly in the postoperative period and for patients with malignancies; (2) management of patients who are administered intravenous heparin; (3) monitoring the coagulation state during liver transplantation; (4) monitoring the coagulation state and management of patients during cardiopulmonary bypass; and (5) diagnosis and treatment of hematologic dysfunctions, particularly hemophilia. Management of patients under warfarin administration, as well as monitoring of the adjustment of subcutaneous heparin prophylaxis in several surgical procedures, should probably belong to this list, but further studies are needed to confirm these roles. Used by experienced hands, TEG is a valuable hemostatic test, the future of which is already present.

Purpose: The purpose of this study was to analyze current attitudes toward the prevention of postoperative venous thromboembolism among North American general surgeons., Methods: A survey regarding awareness of the problem of venous thromboembolism and preferred modalities of prophylaxis was sent to 3500 randomly selected Fellows of the American College of Surgeons., Results: A total of 1018 (29.1%) surveys was returned. Most of the responding surgeons consider venous thromboembolism a serious health problem. Ninety percent of the surgeons use prophylaxis against venous thromboembolism routinely. The most frequently used modalities are intermittent pneumatic compression, low-dose heparin, and elastic stocking. A combination of physical and pharmacologic methods is used by one fourth of respondents, and only 50% start pharmacologic prophylaxis before the surgical procedure. The thrombosis risk factors that are most frequently considered by surgeons when deciding about using prophylaxis are history of venous thromboembolism, immobility, and length of operation., Conclusions: North American surgeons who responded to this survey are well aware of the problem of venous thromboembolism and their approach to prevention has been significantly modified in the last 10 years. Compared with similar European surveys this survey reveals a higher implementations of physical methods such as intermittent pneumatic compression and elastic stockings. Because of the limited response rate and possibility of sampling bias, these findings should be interpreted with caution.

Several methods of prophylaxis have significantly reduced the risk of developing VTE during hospital admission. There is a current tendency toward a reduction in the hospital stay, which does not necessarily mean that patients are protected from experiencing thrombotic complications after leaving the hospital. A number of patients will develop DVT and PE after hospital discharge if prophylaxis is prematurely discontinued while they persist at risk. Further studies are necessary to establish whether extending prophylaxis beyond discharge will reduce the rate of late-onset thromboses and which are the best prophylactic alternatives for the different patient groups at risk. Meanwhile, it is our standard of practice to utilize a combination of GES and either low-dose heparin or warfarin, at least for 3 or 4 weeks after discharge in high-risk patients. In countries where low molecular weight heparins are available, these agents represent an attractive alternative to unfractionated heparin because of their better dosage schedule and safety profile.

Prophylaxis against postoperative venous thromboembolism should be tailored according to the patient's level of risk. However, risk assessment is not yet in widespread use in surgical practice. In this study, 538 general surgical patients were prospectively assessed based on a scoring system containing 20 risk factors. Depending on the total risk factor score, the patients were grouped into low (0 to 1, 34.5%), moderate (2 to 4, 48.5%), or high risk (more than 4, 17.2%) categories. Statistically significant (p less than 0.0001) correlation was found between our results and those of three existing risk assessment systems. Overall, of the 538 patients, 37.2% received prophylaxis; 10%, 42.1%, and 76% received prophylaxis in the low-, moderate-, and high-risk categories, respectively. Mechanical prophylactic modalities (graduated elastic compression and sequential intermittent compression) were preferred over pharmacologic modalities. These results suggest that implementation of prophylaxis remains underutilized despite published reports, including NIH guidelines. Our results indicate that the majority of surgical patients seen in this suburban hospital have two or more risk factors for developing venous thromboembolism.

In summary we have developed a VTE risk assessment system for medical patients based on our prior experience in surgical patients. In this model we divide individuals into low, moderate, and high-risk categories. We realize that our system needs further validation with appropriate diagnostic endpoints to correlate the actual occurrence of venous thromboembolism with the predicted risk on the basis of our score system. Nevertheless, the proposed model reflects one approach to achieving a prophylaxis tailored to the patients' risk.

A technique for treating patients with benign pyloric stenosis and associated choledocholithiasis upon a dilated common bile duct is described. The procedure consists in the performance of a Billroth II partial gastrectomy with the Hofmeinster-Finsterer modification and truncal vagotomy and a simultaneous side-to-end choledochoduodenostomy between the common bile duct and the duodenal stump. We have operated two cases in this way up to now without complications and with good postoperative results.