Objective: This study was performed to determine the effectiveness of recombinant P-selectin glycoprotein ligand Ig (rPSGL-Ig) pretreatment to decrease thrombosis and inflammation in experimental ...venous thrombosis. rPSGL-Ig, a unique mucin-like glycoprotein, has a high affinity for P-selectin.
Methods. Twelve juvenile baboons underwent inferior vena cava (IVC) thrombosis with temporary 6-hour IVC balloon occlusion. Before balloon placement, the animals received rPSGL-Ig (4 mg/kg; n = 8) or saline solution for control (n = 4). The animals underwent evaluation with duplex ultrasound scan imaging, magnetic resonance venography (MRV), phlebography, coagulation profile, and tissue analysis at death for cytokines and vein wall leukocyte morphometrics. With the MRV results, thrombus development, thrombus resolution, and inflammation (gadolinium; square millimeters of enhancement) were assessed.
Results. Each animal provided two time points for evaluation (days 2 and 6 after balloon occlusion). A significant decrease in IVC thrombosis between balloons was found in the rPSGL-Ig animals (1 of 16) versus the control animals (5 of 8; P < .01). The MRV results showed significantly less enhancement in the rPSGL-Ig animals at days 2 and 6 (P < .05). Spontaneous thrombus resolution (including balloon sites) was significantly greater from day 2 to day 6 in the rPSGL-Ig animals versus the control animals (23% vs 2%; P < .001), without pulmonary embolism. Lower interleukin-8, platelet factor IV, and monocyte chemotactic protein-1 levels were found in rPSGL-Ig vein walls without significant differences in vein wall leukocyte morphometrics. There were significantly lower D-dimer levels in the rPSGL-Ig-treated animals (P < .05), but there were no differences in measurements of coagulation. Adequate circulating rPSGL-Ig levels were documented.
Conclusion: Pretreatment with rPSGL-Ig results in: (I) a significant inhibition of thrombosis and vein wall inflammation; (2) a decrease in vein wall cytokine expression; and (3) a promotion of thrombus resolution. Inflammatory inhibition by rPSGL-Ig without anticoagulation therapy provides effective venous thrombosis prophylaxis in experimental venous thrombosis.
Objective: The percutaneous steel Greenfield filter (PSGF) is similar in appearance to the titanium Greenfield filter (TGF) but differs in the length and orientation of the attachment hooks and in ...the over-the-wire delivery system. Because these differences improve ease of insertion and attachment, they may affect patient outcomes and physician practices. The purpose of this study was to evaluate the performance of the PSGF relative to the TGF and to determine whether there had been a change in physician practices. Methods: The Michigan Filter Registry contains data for a prospective cohort of 2188 patients with Greenfield filters. Procedural and long-term outcomes for patients with a PSGF were abstracted. These events were compared with rates for Registry patients who had a TGF. Trends for indication for placement, delivery route, and filter location were also compared with published series. Results: Since 1995, 600 PSGFs have been placed in 599 patients. A 1-year mortality rate of 42% left 349 patients available for annual follow-up, and studies were completed for 231 (66%). Periprocedural events occurred in 2.5% of cases with associated morbidity in 1.5%. The rate of new pulmonary embolism was 2.6%, and vena caval patency was 98.3%. The combined rate of new venous thromboembolic events was 12.5%. Left-sided femoral vein placements increased to 20%, and the major indication for filter placement has become prophylaxis (46%). Conclusions: The PSGF is similar to the TGF with respect to patient outcomes, and it provides decreased rates of asymmetry along with excellent fixation. The flexible carrier system has allowed more frequent access through the left femoral vein. The ease of use and favorable patient outcomes have resulted in more frequent placement for prophylactic indications. (J Vasc Surg 2000;32:888-93.)
The Greenfield filter was the result of collaboration between a surgeon and a petroleum engineer. Originally it was a component of a catheter management approach to massive pulmonary embolism. ...Industry support allowed further technical improvements and long-term patient followup studies.
Venous thromboembolic events (VTE) are potentially preventable causes of morbidity and mortality after injury. We hypothesized that the current clinical incidence of VTE is relatively low and that ...VTE risk factors could be identified.
We queried the ACS National Trauma Data Bank for episodes of deep venous thrombosis (DVT) and/or pulmonary embolism (PE). We examined demographic data, VTE risk factors, outcomes, and VTE prophylaxis measures in patients admitted to the 131 contributing trauma centers.
From a total of 450,375 patients, 1602 (0.36%) had a VTE (998 DVT, 522 PE, 82 both), for an incidence of 0.36%. Ninety percent of patients with VTE had 1 of the 9 risk factors commonly associated with VTE. Six risk factors found to be independently significant in multivariate logistic regression for VTE were age > or = 40 years (odds ratio OR 2.01; 95% confidence interval CI 1.74 to 2.32), lower extremity fracture with AIS > or = 3 (OR 1.92; 95% CI 1.64 to 2.26), head injury with AIS > or = 3 (OR 1.24; 95% CI 1.05 to 1.46), ventilator days >3 (OR 8.08; 95% CI 6.86 to 9.52), venous injury (OR 3.56; 95% CI 2.22 to 5.72), and a major operative procedure (OR 1.53; 95% CI 1.30 to 1.80). Vena cava filters were placed in 3,883 patients, 86% as PE prophylaxis, including in 410 patients without an identifiable risk factor for VTE.
Patients who need VTE prophylaxis after trauma can be identified based on risk factors. The use of prophylactic vena cava filters should be re-examined.
Purpose: The five pneumatic compression devices (PCDs) that are marketed provide mechanical protection from deep venous thrombosis (DVT). They differ with respect to patterns of compression and the ...length of the sleeve. Evidence linking differences to clinical outcomes is lacking. Our purpose was twofold: to evaluate each of the marketed PCDs with respect to effectiveness, compliance, and patient and nursing satisfaction and to determine whether there is a clinical basis for the selection of one device over another. Methods: Each of the marketed devices was used exclusively for a 4-week period. Patients participated in an evaluation including venous duplex ultrasound scan, DVT risk assessment, and device evaluation. Vascular laboratory records were used to document DVT. Compliance was measured by meters installed on all pumps. A ranking matrix was stratified by compression pattern: rapid graduated sequential compression, graduated compression, and intermittent compression, and each device was rated by patients and nurses. Results: The PCDs were used in 1350 cases with a DVT rate of 3.5% ranging from 2% to 9.8% depending on the method of compression. Patients with DVT were older (58 vs 54 years), had better compliance (67% vs 50%), and had more compression days (11 vs 7.2). When thigh-length sleeves were used, a greater proportion of DVT occurred in the proximal segments (71%) as compared with the number of proximal DVT when the calf-length devices were used (52%; P =.21). Devices W, X, and Y had comparable rates of DVT, which were lower than those for V and Z. Compression device Y, with calf and thigh sleeves, achieved the best overall ranking largely because of high scores for patient and nurse satisfaction. Conclusion: Our data appear at odds with commonly held beliefs. We were unable to show a difference in DVT incidence based on the length of the device or the method of compression. Randomized studies are needed to confirm our findings and evaluate hypotheses derived from this study. (J Vasc Surg 2001;34:459-64.)
This study describes, quantifies, and evaluates the University of Michigan Department of Surgery medical malpractice experience for the 1992 to 2002 period. The goal is to gain an understanding of ...what our claims experience has been, what services are highest risk, and where the financial exposure lies.
The study analyzed 308 medical malpractice cases within the Department of Surgery from 1992 through 2002.
There were 263 cases involving a single surgical service (defendant-only) and 70 shared cases involving multiple services. One hundred forty-four cases (47%) were settled with no payment to the plaintiff. Settlements for all cases totaled $38,718,254. The per-case expense (not including legal fees) was $125,708. Legal expenses for all cases totaled $5,356,588, averaging $17,391 per case.
Understanding and sharing institutional data on medical malpractice is critical to developing effective strategies for managing malpractice risk. Although many institutions treat these data as proprietary and confidential, communication of this information generates a better understanding of the opportunities that are available for development and implementation of appropriate risk-management tools.
Pulmonary embolism (PE) is a major health concern that affects approximately 600,000 new patients annually. The diagnosis of PE can be difficult to make, and several imaging studies have been ...developed to aid in this process. Initial evaluation involves the acquisition of a chest radiograph. Findings on radiography, however, are often non-specific. The gold-standard study historically has been pulmonary angiography, with increasing diagnostic yield since the implementation of digital subtraction technology. This is an invasive procedure, however, but the incidence of major complications is low. Less invasive modalities have been developed and include ventilation-perfusion lung scans. These are used as one of the initial screening tests in evaluation of patients with suspected PE. The presence of a high-probability scan usually indicates the presence of a PE, although few patients have high probability scans. The test is significantly affected by underlying pulmonary disease or previous PE. Given this, ventilation-perfusion lung scans are limited as a primary diagnostic tool in the evaluation of suspected PE. Helical computed tomography (CT) is currently under much scrutiny as a diagnostic tool for PE. Currently a prospective, multicenter trial evaluating its efficacy (PIOPED II) has been initiated, but the results are pending. Preliminary reports suggest the helical CT and venous phase CT may become a first line study in patient evaluation. The diagnosis of PE is challenging and several imaging modalities are currently used to assist the clinician. Currently, multiple modalities are often required to make the diagnosis. With the advent of new technology and improved imaging techniques, the diagnosis of PE will become easier.
Purpose: The purpose of this study was to compare the efficacy of P-selectin inhibition with standard anticoagulant and thrombolytic therapy in a rodent model of established deep vein thrombosis ...(DVT).
Methods: Rats underwent temporary inferior vena cava (IVC) ligation for 2 days to create a stasis-induced thrombosis. On day 2, the animals had the IVC ligature removed and received either recombinant P-selectin glycoprotein ligand-Ig (rPSGL-Ig; 4 mg/kg) intravenously, low-molecular weight heparin (LMWH; 450 IU/kg) subcutaneously, tissue plasminogen activator (tPA; 0.5 mg/kg) intravenously, combination rPSGL-Ig plus tPA, or saline vehicle. IVC segments were harvested from rats at 4 (n = 8) and 7 (n = 3) days after treatment. All treatments were given as a single dose except for daily LMWH. Evaluation included contrast venography with computer image analysis, thrombus weight/length (mass), vein wall leukocyte counts, cytokine and tissue factor analysis with enzyme-linked immunosorbent assay, and (ED1) monocyte immunohistochemical staining. Collagen was estimated with a quantitative assay.
Results: Contrast venography revealed that rats with both rPSGL-Ig and tPA treatment had significantly smaller thrombi as compared with controls at day 7 (0.34 ± 0.07 cm
2 and 0.34 ± 0.05 cm
2 versus 0.68 ± 0.13 cm
2;
P < .05). LMWH and tPA groups had significantly decreased thrombus mass at harvest compared with controls on day 4 (0.06 ± 0.009 g/cm and 0.08 ± 0.01 g/cm versus 0.1 ± 0.005 g/cm;
P < .05), and rPSGL-Ig showed a similar trend (
P = .072). Vein wall, but not thrombus, monocytes were more numerous in those rats receiving rPSGL-Ig versus controls at day 4 (30 ± 4 cells/5 high power fields HPFs versus 19 ± 2 cells/5 HPFs;
P
< .05) and at day 7 (32 ± 2 cells/5 HPFs versus 20 ± 3 cells/5 HPFs;
P < .05). rPSGL-Ig treatment was associated with significantly reduced vein wall collagen at day 7 versus controls (1.3 ± 0.6 pg/mg versus 3.7 ± 0.5 pg/mg;
P < .05) and a trend toward lower tissue factor levels.
Conclusion: rPSGL-Ig, LMWH, and tPA showed equal DVT resolution efficacy over 7 days. However, only rPSGL-Ig was associated with a decrease in vein wall fibrosis, suggesting that purely accelerating DVT resolution may not decrease long-term vein scarring. (J Vasc Surg 2002;36:928-38.)
Thrombosis and inflammation are closely related. However, the response of the vein wall to venous thrombosis has been poorly documented. This study examines the hypothesis that venous thrombosis is ...associated with an inflammatory response in the vein wall. In a rat model of inferior vena caval thrombosis, vein wall was temporally examined for inflammation by assessment of histopathology, leukocyte morphometrics, and cytokine levels. Animals were killed 1 hour and 1, 3, and 6 days after thrombus induction. Our findings demonstrated an early (day 1) neutrophil infiltration into the vein wall followed by a later (days 3 and 6) monocyte/macrophage and lymphocyte response. Cytokines were elevated only under conditions of venous thrombosis. Levels of epithelial neutrophil activating protein-78 (ENA-78), tumor necrosis factor-alpha (TNF), interleukin-6, and JE/monocyte chemoattractant protein-1 (JE/MCP-1) increased over the 6-day period, while macrophage inflammatory protein-1 alpha (MIP-1 alpha) peaked at day 3 after thrombus induction. Additionally, rats were passively immunized with neutralizing antibodies to TNF, ENA-78, MIP-1 alpha, JE/MCP-1, intercellular adhesion molecule-1 (ICAM-1), and CD18 compared with control antibodies. The most effective antibody early after thrombus induction for attenuating vein wall neutrophil extravasation was anti-TNF (P < .01). The monocyte/macrophage extravasation was inhibited most by anti-ICAM-1 followed by anti-TNF (P < .01). These findings demonstrate that venous thrombosis is associated with significant vein wall inflammation that is partially inhibited by neutralizing antibodies to cytokines and adhesion molecules. (Arterioscler Thromb Vasc Biol. 1995;15:258-268.)
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