Effects of thrombolysis and venous thrombectomy on valvular competence, thrombogenicity, venous wall morphology, and function

Construction of a Prediction Model for Post-thrombotic Syndrome after Deep Vein Thrombosis Incorporating Novel Inflammatory Response Parameter Scoring

OBJECTIVE

To investigate the independent predictive factors for post-thrombotic syndrome (PTS) and to construct a risk prediction model for PTS by incorporating a novel inflammatory response parameter (NPM score) scoring.

METHODS

A retrospective study analyzed patients diagnosed with lower extremity deep vein thrombosis (LEDVTs at the Affiliated Hospital of Chengde Medical College from January 2018 to January 2022. The Villalta scale was used to assess the occurrence of PTS 6-24 months after discharge. Patients were randomly divided into a training set and a validation set at a ratio of 7:3. In the training set, univariate analysis was performed on meaningful continuous variables, and those with differences were converted into dichotomous variables based on optimal cutoff values. Variable selection was performed using Log Lambda and Least Absolute Shrinkage and Selection Operator 10-fold cross-validation, followed by multivariable logistic regression analysis on selected variables for model construction. The model underwent internal validation in the validation set and external validation in an independent external cohort, including discriminative analysis, calibration analysis, and clinical decision curve analysis (DCA), with the model's rationale being evaluated lastly.

RESULTS

A total of 356 patients with lower extremity DVT were included, with 249 in the training set for model construction and 107 in the validation set for internal validation, along with 37 external patients for external validation. A composite score of inflammatory response parameters, including the neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and monocyte to high-density lipoprotein cholesterol ratio (MHR) (NLR-PLR-MHR score, NPM score), was developed, showing a significantly higher NPM score in the PTS group compared to the non-PTS group (P < 0.05). Predictive factors related to the risk of PTS occurrence included staging (OR = 6.83, 95% CI: 2.74-18.04), varicose veins (OR = 7.30, 95% CI: 2.29-25.75), homocysteine (Hcy) (OR = 1.12, 95% CI: 1.04-1.22), NPM score (OR = 3.13, 95% CI: 1.94-5.36), standardized anticoagulant therapy (OR = 5.77, 95% CI: 1.25-27.62), and one-stop treatment (OR = 0.04, 95% CI: 0.00-0.35) were incorporated into the Nomogram model. The model showed good discrimination with a concordance index of 0.918 (95% CI: 0.876-0.959) for model construction, 0.843 (95% CI: 0.741-0.945) for internal validation, and 0.823 (95% CI: 0.667-0.903) for external validation. In the Nomogram model, internal and external validation calibration curves showed good agreement between observed and predicted values. DCA indicated that the Nomogram model predicted PTS risk probability thresholds ranging from 3% to 98% for model construction, 5%-97% for internal validation, and 10%-80% for external validation, demonstrating better net benefit for predicting PTS risk in the model, internal, and external validation. Rationality analysis showed the model and internal validation had higher discrimination and clinical net benefit than other clinical indices.

CONCLUSIONS

The NPM score combined with stage, varicose veins, Hcy, standardized anticoagulant therapy, and one-stop treatment in the Nomogram model provides a practical tool for health care professionals to assess the risk of PTS in DVT patients, enabling early identification of high-risk patients for effective PTS prevention.

Comparative Study of Two Different Access Points, One Tibial Vein and the Popliteal Vein, for Catheter-Directed Thrombolysis in the Treatment of Acute Mixed Lower Extremity Deep Vein Thrombosis

BACKGROUND

Although the popliteal vein approach is commonly used for catheter-directed thrombolysis (CDT) treatment in patients with acute lower extremity deep vein thrombosis (DVT), CDT via a new access route, the posterior tibial vein, is also used and has demonstrated good results. However, this tibial approach has not been tested in large samples. In this article, we compare the early efficacy of CDT using the tibial and popliteal vein approaches for the treatment of acute mixed lower extremity DVT.

METHODS

In this retrospective cohort study, 87 patients with acute mixed lower extremity DVT treated at the Department of Interventional Medicine of Zhuhai People's Hospital were enrolled; those with tibial vein access and popliteal vein access were included in the observation (n = 55) and control (n = 32) groups, respectively. The safety and efficacy of CDT via tibial vein access were investigated by collecting and comparing indicators such as venous patency, thrombus removal effect, thigh and calf circumference difference, swelling reduction rate of the affected limb, surgical complications, and postdischarge complication rate of the patients in the 2 groups.

RESULTS

The postoperative thrombus clearance effect of the observation group was significantly better than that of the control group (P < 0.05), and the postoperative venous patency rate of the observation group was 83.2 ± 15.7%, which was higher than that of the control group (62.2 ± 38.2%) (P = 0.005). The swelling reduction rate of the lower extremity was 74.0 ± 33.8% in the observation group and 51.4 ± 30.0% in the control group, with a statistically significant difference (P = 0.002). However, there was no statistically significant difference (P > 0.05) in the rates of thigh swelling reduction, bleeding-related complications, or postoperative complications between the 2 groups of patients.

CONCLUSIONS

CDT via the tibial vein approach is safe, effective, and may be a better approach for CDT access, offering superior thrombus clearance, venous patency, and lower extremity swelling reduction postoperatively.

2022 Update of the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) Domain 6: Defining rational use of thrombolytics

OBJECTIVES

To systematically review available evidence and establish guidelines related to the use of thrombolytics for the management of small animals with suspected or confirmed thrombosis.

DESIGN

PICO (Population, Intervention, Control, and Outcome) questions were formulated, and worksheets completed as part of a standardized and systematic literature evaluation. The population of interest included dogs and cats (considered separately) and arterial and venous thrombosis. The interventions assessed were the use of thrombolytics, compared to no thrombolytics, with or without anticoagulants or antiplatelet agents. Specific protocols for recombinant tissue plasminogen activator were also evaluated. Outcomes assessed included efficacy and safety. Relevant articles were categorized according to level of evidence, quality, and as to whether they supported, were neutral to, or opposed the PICO questions. Conclusions from the PICO worksheets were used to draft guidelines, which were subsequently refined via Delphi surveys undertaken by the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) working group.

RESULTS

Fourteen PICO questions were developed, generating 14 guidelines. The majority of the literature addressing the PICO questions in dogs is experimental studies (level of evidence 3), thus providing insufficient evidence to determine if thrombolysis improves patient-centered outcomes. In cats, literature was more limited and often neutral to the PICO questions, precluding strong evidence-based recommendations for thrombolytic use. Rather, for both species, suggestions are made regarding considerations for when thrombolytic drugs may be considered, the combination of thrombolytics with anticoagulant or antiplatelet drugs, and the choice of thrombolytic agent.

CONCLUSIONS

Substantial additional research is needed to address the role of thrombolytics for the treatment of arterial and venous thrombosis in dogs and cats. Clinical trials with patient-centered outcomes will be most valuable for addressing knowledge gaps in the field.

Use of electron microscopy to study platelets and thrombi

Electron microscopy has been a valuable tool for the study of platelet biology and thrombosis for more than 70 years. Early studies using conventional transmission and scanning electron microscopy (EM) provided a foundation for our initial understanding of platelet structure and how it changes upon platelet activation. EM approaches have since been utilized to study platelets and thrombi in the context of basic, translational and clinical research, and they are instrumental in the diagnosis of multiple platelet function disorders. In this brief review, we provide a sampling of the many contributions EM based studies have made to the field, including both historical highlights and contemporary applications. We will also discuss exciting new imaging modalities based on EM and their utility for the study of platelets, hemostasis and thrombosis into the future.

Long-Term Outcome of Catheter-Directed Thrombolysis in Pregnancy-Related Venous Thrombosis

BACKGROUND Venous thromboembolism (VT) is a leading cause of maternal mortality and morbidity worldwide. Catheter-directed thrombolysis (CDT) is an effective and safe treatment modality for VT patients. However, the long-term outcome of CDT in pregnancy-related venous thrombosis are unclear. The aim of this study was to assess long-term results of pregnancy-related VT patients. MATERIAL AND METHODS We reviewed 41 pregnancy-related deep venous thrombosis (DVT) patients who underwent CDT from February 2008 to May 2015. Clinical data, including demographic variables, disease location, vascular risk factors, treatment regimen, interventional procedure and complications, were collected retrospectively. Clinical and color-duplex ultrasonography were performed to monitor venous patency during follow-up. Post-thrombotic syndrome (PTS) was assessed with the Villalta scale and quality of life (QOL) was evaluated by the VEINES-QOL/Sym questionnaire. RESULTS Twenty-three patients underwent spontaneous abortion or induced abortion within 3 months before DVT, and 18 patients had DVT during the first 3 months after delivery. Technical success was achieved in all patients. Grade III (complete) lysis was obtained in 15 patients and grade II (partial) lysis was obtained in 21 patients. The follow-up period was 3 years. Twenty-eight patients had venous patency at 3-year follow-up; 36.6% of patients developed mild or moderate PTS (Villalta score 5-14) and 4.8% with severe PTS (Villalta score ≥15). VEINES-QOL/Sym scores were 55.24±7.35 and 53.25±6.65, respectively. CONCLUSIONS Catheter-directed thrombolysis is a reliable and safe treatment modality for postnatal or abortion patients with DVT. CDT can reduce the incidence rate of PTS and increase the quality of life.

The Midterm Effect of Iliac Vein Stenting following Catheter-directed Thrombolysis for the Treatment of Deep Vein Thrombosis

BACKGROUND

When following catheter-directed thrombolysis (CDT) for deep vein thrombosis (DVT), the stenosed iliac veins is controversy. To evaluate the mid-term outcomes of CDT with or without stent implantation for DVT in the presence of iliac vein compression.

METHODS

Seventy-three patients with iliac vein compression following CDT for acute lower extremity DVT from January 2009 to December 2014 were retrospectively analyzed. There were 32 males and 41 females, with average age of 53.57 ± 15.60 years (median: 45 years, range: 20-79 years). After CDT, patients with iliac vein compression were divided into 2 groups: the stenting group (n = 40) and the nonstenting group (n = 33). Patency rate of the deep vein, chronic change of vessels, clinical, etiological, anatomical, and pathological elements (CEAP) classification, venous clinical severity score, and Villalta scale were chosen to evaluate the midterm and long-term outcomes.

RESULTS

Eighty-eight limbs among the patients (58 unilateral and 15 bilateral) were followed with mean time of 38.38 ± 14.91 months. The difference in vein patency between 2 groups (85.17 ± 25.62 vs. 54.61 ± 40.42) was statistically significant (P < 0.05). According to the C in CEAP classification, the difference in clinical manifestations between the 2 groups was statistically significant (P < 0.05). In addition, the Villalta scale scores were also significantly different between the 2 groups (1.73 ± 2.86 vs. 4.39 ± 5.16, P < 0.05).

CONCLUSIONS

Stent implantation in severely stenosed iliac segments following CDT for lower extremity DVT increased the patency of deep veins and improved midterm quality of life compared with that of nonstenting.

Comparison of Direct Iliofemoral Stenting Following AngioJet Rheolytic Thrombectomy vs Staged Stenting After AngioJet Rheolytic Thrombectomy Plus Catheter-Directed Thrombolysis in Patients With Acute Deep Vein Thrombosis

Purpose: To compare the treatment outcomes in patients with acute proximal deep vein thrombosis (DVT) and iliofemoral stenosis who underwent either direct stenting after AngioJet rheolytic thrombectomy or staged stenting after AngioJet thrombectomy plus catheter-directed thrombolysis with urokinase. Methods: From June 2014 to February 2016, 91 DVT patients underwent 2 treatments for duplex-verified iliofemoral stenosis: direct stenting (n = 46; mean age 54.8 years; 32 men) or staged stenting (n = 45; mean age 56.5 years; 27 men). The degree of patency after thrombectomy or thrombolysis was evaluated using the Venous Registry Index (VRI), while the risk of postthrombotic syndrome (PTS) was evaluated according to the Villalta scale. Patients were followed with periodic duplex ultrasound scans up to 1 year. Results: The technical success rates were 100% in both groups; there was no 30-day mortality. Immediate (24-hour) clinical improvement was achieved in 42 (91%) of 46 direct group patients vs 33 (73%) of 45 staged group patients (p<0.001). A significant reduction (p<0.001) in the length of hospital stay was noted in the direct group (4.59±0.91) compared with that in the staged group (5.8±1.6). The stents used in the direct group were longer but with similar diameter compared with the staged group. The thrombolysis rates were 81.50%±5.76% in the direct group and 85.67%±3.84% in the staged group (p<0.001). The VRIs declined (improved) significantly in both groups (11.68±1.92 to 3.21±1.44 in the direct group and 12.17±2.29 to 2.36±1.19 in the staged group, both p<0.001). The Villalta scores were significantly better in the staged group (p<0.001). Recurrent DVT occurred in 2 patients in the direct group. The primary patency rates at 1 year were 93.5% in the direct group and 97.8% in the staged group (p=0.323). Conclusion: Both direct and staged stenting are effective treatment modalities for patients with acute proximal DVT. Compared with staged stenting, direct stenting provides similar treatment success and a significant reduction in the length of hospital stay; however, it has lower thrombolysis efficacy, and the risk of PTS at 1 year is greater with direct stenting.

Surgical management of iliofemoral vein thrombosis during pregnancy and the puerperium

BACKGROUND

The risk of deep venous thrombosis is elevated during pregnancy and the puerperium. Therapy is usually limited to conservative measures as invasive thrombus removal is feared because of possible complications. However, leg- or life-threatening situations require fast thrombus removal, and the long-term rate of post-thrombotic syndrome (PTS) may be reduced by venous recanalization. Our center's experience may give support to surgical venous thrombectomy (VT).

METHODS

Between 1996 and 2016, all women who received VT for pregnancy-related deep venous thrombosis in our department were included. Retrospective data were combined with a current follow-up.

RESULTS

The study included 82 women with a mean age of 29 years (17-38 years). An additional arteriovenous fistula was performed in 79 and planned simultaneous cesarean section in 13 patients. Neither pulmonary emboli nor fetal complications occurred during surgery, and perioperative and postoperative mortality was 0%. Operative revision was required in 38% mainly for rethrombosis (24%) and bleeding (12%). One fetus died 2 months after VT of unrelated causes. After a mean of 83 months, complete venous recanalization was seen in 88%, venous valve sufficiency in 90%, and PTS in 31% without any ulcers. At 10 years, PTS incidence rose to reach 50% with limited statistical significance because of the number of patients reaching long-term follow-up.

CONCLUSIONS

Iliofemoral venous recanalization during pregnancy can be performed safely in a specialized center, with lower PTS rates than in historical controls.

Original approach for thrombolytic therapy in patients with Ilio-femoral deep vein thrombosis : 2 years follow-up

Objective

The aim of the study was to discuss the results of catheter-directed thrombolysis and complementary procedures to treat acute iliofemoral deep vein thrombosis (DVT) evaluating the safety and effectivness of an easy access such as the Great Saphenous Vein.

Methods and materials

A total of 22 consecutive patients with iliofemoral thrombosis and two patients with femoro-popliteal thrombosis on recent onset diagnosed with Ultrasound Doppler and contrast venography underwent intrathrombus drip infusion of urokinase while intravenous heparin was continued using saphenical access. Residual venous stenosis were treated in six patients by percutaneous balloon Angioplasty and stenting. All patients underwent routine venous duplex imaging at 30 days, 3 months, 6 months and every 6 months thereafter.

Results

Complete patency of thrombosed veins was restored in 22 patients (91 %) with prompt symptomatic relief. There were no major complications in the immediate outcomes. At follow-up, two patients reported a persistant slim iliac vein stenosis, two patients had post-thrombotic syndrome, and two patients showed Deep Vein Reflux.

Conclusion

Local thrombolysis using saphenical access was a safe and effective approach for the treatment of acute iliofemoral deep vein thrombosis. It seems to be a valid, easy and safe alternative, reducing the risks of haematoma and venous lesions, which can be observed when using femoral, popliteal, and trans-jugular access.

The results of aspiration thrombecomy in the endovascular treatment for iliofemoral deep vein thrombosis

Purpose

The aim of this study is to evaluate the results of aspiration thrombectomy (AT) in the endovascular treatment for iliofemoral deep vein thrombosis (DVT) through the comparison of catheter directed thrombolysis (CDT) alone group and CDT with AT group.

Methods

From November 2001 to April 2011, 100 patients received endovascular treatment with CDT alone or CDT with AT for iliofemoral DVT at Yeungnam University Medical Center. We compared procedure, clinical outcomes and complications between the two groups.

Results

The mean age of patients was 60.48 ± 14.57 years. The patients consisted of 41 men and 59 women. CDT alone and CDT with AT were performed in 29 and 71 patients, respectively. The mean procedural time of the CDT-alone group was longer than the CDT with AT group (P < 0.001) and dose of urokinase used during the procedure significantly decreased in the CDT with AT group (P < 0.001). There were no statistically significant differences in clinical outcomes between the two groups. Cases of pulmonary embolism was not noted in each group in our series, but entrapped thrombus during procedure was noted in 6 of 37 in the CDT with AT group and 0 of 9 in the CDT-alone group among 46 patients with prophylactic inferior vena cava (IVC) filter insertion.

Conclusion

In conclusion, CDT with AT is safe and effective for the treatment of an acute iliofemoral DVT. In AT treatment, prophylactic IVC filter insertion should be considered for the prevention of pulmonary embolism by floating thrombi.

Management of proximal deep vein thrombosis

Iliofemoral DVT constitutes approximately 20-25% of lower limb DVT and represents a specific subgroup of patients at highest risk for post-thrombotic syndrome (PTS). Anticoagulation alone has no significant thrombolytic activity and has not impact on PTS prevention. Early thrombus removal has reduced PTS in uncontrolled reports and reviews but major trials are awaited. The optimal timing for treatment appear to be thrombus <2 weeks old and, methods for thrombus removal include direct open or suction thrombectomy, catheter directed thrombolysis (CDT), with or without percutaneous mechanical thrombectomy (PMT) devices. Three principle types of PMT device are in use (rotational, rheolytic and ultrasound enhanced devices) and are combined with CDT in pharmocomechanical thrombolysis (PhMT) to enhance early thrombus removal. These devices have individual device specific attributes and side effects that are additional to the bleeding complications of thrombolysis. A number of additional interventions may be utilised to the improve results of CDT and PhMT. IVC filter deployment to reduce periprocedural PE, is supported by little evidence unless an indication for its use already exists. However, balloon venoplasty and vein stents undoubtedly vein patency after treatment. Early thrombus removal comes with additional upfront costs derived from devices, imaging and critical care bed usage. However, significant potential savings from reduction in PTS and rethrombosis rates may reduce overall societal costs. This review focuses on iliofemoral thrombosis, however, the less commonly encountered but clinically important subclavian vein thrombosis is also discussed.

Catheter-directed thrombolysis of proximal lower extremity deep vein thrombosis: a prospective trial with venographic and clinical follow-up

PURPOSE

To prospectively evaluate the primary and long-term venographic and clinical results of catheter-directed thrombolysis in the treatment of proximal deep vein thrombosis (DVT) of lower extremity.

MATERIALS AND METHODS

Fifty-six patients with mean age of 48 (range 15-81) years with acute DVT (symptom duration of less than 2 weeks), extending to high femoral (16 patients) or iliac vein (40 patients) were treated with selective catheter-directed thrombolysis. The mean total dose of 3.8 (range 1.0-8.1) million units of urokinase was administered during a mean of 39 (range 6-72) hours. Endovascular stenting was performed in 9 of the iliac DVT patients.

RESULTS

Complete procedural venographic success was achieved in 79% of patients. Major complications were noted in 7% of patients and the total rate of complications was 13%. Mean venographic follow-up was 3.5 years (range 3 months to 9.6 years); well preserved femoral vein valves and fully recanalized deep crural veins were observed in 83% and 57% of patients. Normal clinical findings in the affected limb were noted during the latest follow-up visit in 67% of patients. Clinical post-thrombotic syndrome occurred in 9% of patients.

CONCLUSION

Catheter-directed thrombolysis achieves good primary success with acceptable complication rate and effectively reduces prevalence of post-thrombotic syndrome.

Catheter-directed thrombolysis with a continuous infusion of low-dose urokinase for non-acute deep venous thrombosis of the lower extremity

OBJECTIVE

We wanted to evaluate the feasibility of catheter-directed thrombolysis with a continuous infusion of low-dose urokinase for treating non-acute (less than 14 days) deep venous thrombosis of the lower extremity.

MATERIALS AND METHODS

The clinical data of 110 patients who were treated by catheter-directed thrombolysis with a continuous infusion of low-dose urokinase for lower extremity deep venous thrombosis was analysed. Adjunctive angioplasty or/and stenting was performed for the residual stenosis. Venous recanalization was graded by pre- and post-treatment venography. Follow-up was performed by clinical evaluation and Doppler ultrasound.

RESULTS

A total of 112 limbs with deep venous thrombosis with a mean symptom duration of 22.7 days (range: 15-38 days) were treated with a urokinase infusion (mean: 3.5 million IU) for a mean of 196 hours. After thrombolysis, stent placement was performed in 25 iliac vein lesions and percutaneous angioplasty (PTA) alone was done in five iliac veins. Clinically significant recanalization was achieved in 81% (90 of 112) of the treated limbs; complete recanalization was achieved in 28% (31 of 112) and partial recanalization was achieved in 53% (59 of 112). Minor bleeding occurred in 14 (13%) patients, but none of the patients suffered from major bleeding or symptomatic pulmonary embolism. During follow-up (mean: 15.2 months, range: 3-24 months), the veins were patent in 74 (67%) limbs. Thirty seven limbs (32%) showed progression of the stenosis with luminal narrowing more than 50%, including three with rethrombosis, while one revealed an asymptomatic iliac vein occlusion; 25 limbs (22%) developed mild post-thrombotic syndrome, and none had severe post-thrombotic syndrome. Valvular reflux occurred in 24 (21%) limbs.

CONCLUSION

Catheter-directed thrombolysis with a continuous infusion of low-dose urokinase combined with adjunctive iliac vein stenting is safe and effective for removal of the clot burden and for restoration of the venous flow in patients with non-acute lower extremity deep venous thrombosis.

Deep vein thrombosis: endovascular management

Deep vein thrombosis is a condition that affects hundreds of thousands of patients each year. The major complications include pulmonary embolus with the potential for loss of life and post-thrombotic syndrome with the potential for loss of function of the limb. Extensive clinical research over the last 40 years has improved the techniques to remove the thrombus from the affected limb and reduce the likelihood of developing post-thrombotic syndrome. These treatments have included intravenous systemic thrombolysis, catheter-directed thrombolysis, surgical thrombectomy, and most recently pharmacomechanical thrombectomy to rapidly fragment, lyse, and remove the thrombus from the affected limb. This last technique may finally transform the treatment of acute deep vein thrombus from strictly conservative medical therapy to a minimally invasive procedure that can remove the thrombus to improve the quality of life of millions of individuals suffering from the symptoms of deep vein thrombosis. Mt Sinai J Med 77:286-295, 2010. (c) 2010 Mount Sinai School of Medicine.

Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about treatment for venous thromboembolic disease is part of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do or do not outweigh risks, burden, and costs. Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see "Grades of Recommendation" chapter). Among the key recommendations in this chapter are the following: for patients with objectively confirmed deep vein thrombosis (DVT) or pulmonary embolism (PE), we recommend anticoagulant therapy with subcutaneous (SC) low-molecular-weight heparin (LMWH), monitored IV, or SC unfractionated heparin (UFH), unmonitored weight-based SC UFH, or SC fondaparinux (all Grade 1A). For patients with a high clinical suspicion of DVT or PE, we recommend treatment with anticoagulants while awaiting the outcome of diagnostic tests (Grade 1C). For patients with confirmed PE, we recommend early evaluation of the risks to benefits of thrombolytic therapy (Grade 1C); for those with hemodynamic compromise, we recommend short-course thrombolytic therapy (Grade 1B); and for those with nonmassive PE, we recommend against the use of thrombolytic therapy (Grade 1B). In acute DVT or PE, we recommend initial treatment with LMWH, UFH or fondaparinux for at least 5 days rather than a shorter period (Grade 1C); and initiation of vitamin K antagonists (VKAs) together with LMWH, UFH, or fondaparinux on the first treatment day, and discontinuation of these heparin preparations when the international normalized ratio (INR) is > or = 2.0 for at least 24 h (Grade 1A). For patients with DVT or PE secondary to a transient (reversible) risk factor, we recommend treatment with a VKA for 3 months over treatment for shorter periods (Grade 1A). For patients with unprovoked DVT or PE, we recommend treatment with a VKA for at least 3 months (Grade 1A), and that all patients are then evaluated for the risks to benefits of indefinite therapy (Grade 1C). We recommend indefinite anticoagulant therapy for patients with a first unprovoked proximal DVT or PE and a low risk of bleeding when this is consistent with the patient's preference (Grade 1A), and for most patients with a second unprovoked DVT (Grade 1A). We recommend that the dose of VKA be adjusted to maintain a target INR of 2.5 (INR range, 2.0 to 3.0) for all treatment durations (Grade 1A). We recommend at least 3 months of treatment with LMWH for patients with VTE and cancer (Grade 1A), followed by treatment with LMWH or VKA as long as the cancer is active (Grade 1C). For prevention of postthrombotic syndrome (PTS) after proximal DVT, we recommend use of an elastic compression stocking (Grade 1A). For DVT of the upper extremity, we recommend similar treatment as for DVT of the leg (Grade 1C). Selected patients with lower-extremity (Grade 2B) and upper-extremity (Grade 2C). DVT may be considered for thrombus removal, generally using catheter-based thrombolytic techniques. For extensive superficial vein thrombosis, we recommend treatment with prophylactic or intermediate doses of LMWH or intermediate doses of UFH for 4 weeks (Grade 1B).

Rheolytic pharmacomechanical thrombectomy in experimental chronic deep vein thrombosis: effect of L-arginine on thrombogenicity and endothelial vasomotor function

PURPOSE

Endovascular removal of intravascular thrombus using the AngioJet rheolytic thrombectomy (RT) system has been shown to be clinically effective. This system also permits the concomitant infusion of thrombolytic agent followed by thrombectomy, thus creating a novel strategy known as pharmacomechanical thrombectomy (PMT). Although these interventions have gained wide clinical application, little is known regarding the vessel wall response following thrombectomy therapy. The aims of this study were to assess the effect of thrombectomy interventions on endothelial function in a porcine model of deep venous thrombosis (DVT) and to evaluate the effect of nitric oxide (NO) precursor L-arginine on endothelial function following thrombectomy therapy.

METHODS

Deep vein thrombosis was created in bilateral iliac veins by deploying a self-expanding stent-graft incorporating an intraluminal stenosis from a groin approach. Five pigs underwent sham operation. Following 14 days of DVT, animals were randomized to three groups: the first group received RT treatment (RT group, n = 5); the second group received pharmacomechanical thrombectomy (PMT) with tissue plasminogen activator (alteplase 10 mg; PMT group, n = 5); and the third group received PMT with tPA plus intravenous L-arginine (20 mmol/l) (arginine group, n = 5). Iliac vein patency was evaluated by venography and intravascular ultrasound at 1 week. Nitric oxide level was determined by a chemiluminescent assay of the nitrite/nitrate metabolites (NO(x)). Thrombogenicity was evaluated by radiolabeled platelet and fibrin deposition. Veins were harvested and evaluated with light microscopy and scanning electron microscopy (SEM). Endothelial function was evaluated using organ chamber analysis.

RESULTS

The luminal areas in the sham, RT, PMT, and arginine groups were 34 +/- 10 mm(2), 21 +/- 13 mm(2), 35 +/- 18 mm(2), and 37 +/- 16 mm(2), respectively. All iliac veins remained patent at 2 weeks. No difference in endothelial cell structure was observed between the three treatment groups by means of light microscopic or SEM examination. A decrease in platelet deposition occurred in the arginine group compared to the RT and PMT groups (P < 0.05). The arginine group also showed a greater endothelium-dependent relaxation compared to the RT or PMT groups in response to A23187, bradykinin, and ADP (P < 0.05). Local NO(x) level was higher in the arginine group than in the RT or PMT group (2.6 +/- 0.6 micromol/l versus 0.3 +/- 0.1 micromol/l and 0.3 +/- 0.2 micromol/l; P < 0.01).

CONCLUSIONS

AngioJet RT and PMT interventions resulted in similar attenuated endothelium-dependent vasoreactivity and morphologic effect. L-Arginine supplementation preserves endothelial vasoreactivity and reduces platelet deposition following PMT in iliac DVT. Additionally, L-arginine enhances NO production at sites of venous thrombosis. The NO precursor L-arginine may have a therapeutic potential in preserving endothelial function following mechanical thrombectomy.

Treatment of Acute Iliofemoral Deep Venous Thrombosis: A Strategy of Thrombus Removal

Patients with acute iliofemoral deep vein thrombosis (DVT) suffer the most severe postthrombotic sequelae. The majority of physicians treat all patients with acute DVT with anticoagulation alone, despite evidence that postthrombotic chronic venous insufficiency, leg ulceration, and venous claudication are common in patients treated only with anticoagulation. The body of evidence to date in patients with iliofemoral DVT suggests that a strategy of thrombus removal offers these patients the best long-term outcome. Unfortunately, currently published guidelines use outdated experiences to recommend against the use of techniques designed to remove thrombus, ignoring recent clinical studies showing significant benefit in patients who have thrombus eliminated. Contemporary venous thrombectomy, intrathrombus catheter-directed thrombolysis, and pharmacomechanical thrombolysis are all options that can be offered to successfully remove venous thrombus with increasing safety. The authors review evidence supporting the rationale for thrombus removal and discuss the most effective approaches for treating patients with acute iliofemoral DVT.

Late results of catheter-directed recombinant tissue plasminogen activator fibrinolytic therapy of iliofemoral deep venous thrombosis

PURPOSE

To evaluate the efficacy of catheter-directed low-dose recombinant tissue-type plasminogen activator infusion in the treatment of iliofemoral deep venous thrombosis and prevention of post-thrombotic syndrome.

METHOD

Eighteen patients (out of 260 evaluated) with acute iliofemoral deep venous thrombosis and no previous evidence of venous insufficiency were prospectively selected for thrombolytic therapy. Catheter-directed low-dose recombinant tissue-type plasminogen activator (1 mg/h) was infused into the thrombotic segments.

RESULTS

Effective fibrinolysis was achieved in 14 of 18 cases, with correlation between effective fibrinolysis and major/complete resolution of acute signs and symptoms (P <.01). There were no episodes of major complications. Four patients presented with early rethrombosis (1 to 8 weeks). Individuals were followed for a period up to 131 weeks (average, 85.2). The incidence of clinical signs and symptoms of venous insufficiency and duplex-scan findings of valvular reflux was significantly lower in the patients in which lytic therapy succeeded and patency was kept, compared with patients experiencing acute therapeutic failure or rethrombosis (P <.01).

CONCLUSIONS

Low-dose recombinant tissue-type plasminogen activator fibrinolytic therapy is safe and effective in the treatment of acute iliofemoral venous thrombosis. The late evolution as revealed clinically and by ultrasound was superior in patients for whom lytic therapy was effective.

Catheter Directed Thrombolysis for Treatment of Ilio-femoral Deep Venous Thrombosis is Durable, Preserves Venous Valve Function and May Prevent Chronic Venous Insufficiency

OBJECTIVES

To investigate the results of catheter directed thrombolysis offered to patients with acute femoro-iliac deep venous thrombosis (DVT).

DESIGN

Retrospective analysis of all patients treated with this modality at Gentofte Hospital until December 2003.

MATERIAL

Forty-five consecutive patients treated between June 1999 and December 2003 with a median age of 31 years. All patients had femoro-iliac DVT with an average anamnesis of 6 days.

METHODS

All patients were treated by catheter directed infusion of alteplase into the popliteal vein. After thrombolysis residual venous stenoses were treated by percutaneous balloon angioplasty (PTA) and stenting. Patients were followed with color-duplex scanning for assessment of venous patency and reflux.

RESULTS

Forty-two of 45 (93%) of cases were treated successfully with reopening of the thrombosed vein segments. In 30 of 45 cases a residual stenosis was treated by PTA and stenting. Only one serious complication was observed: Compartment syndrome of the forearm where arterial punctures had been taken. After an average of 24 months follow-up were no cases of re-thrombosis among the 42 patients discharged with open veins. Only two of 41 with presumed normal venous valve function prior to DVT developed reflux during follow-up.

CONCLUSION

In this selected patient group, catheter directed thrombolysis seems effective in treating acute DVT, it appears durable and preserves venous valve function in the majority. The method needs to be tested in a randomised controlled trial.

Endovascular management of iliofemoral venous occlusive disease

New developments in the management of both acute and chronic iliac vein occlusive disease offer exciting options for the treatment of this often debilitating condition. Percutaneous clot removal using thrombolysis, mechanical thrombectomy, or a combination of the two is fast becoming the treatment of choice for patients presenting with acute iliofemoral deep vein thrombosis. Recanalization of chronic iliac vein occlusions with balloon angioplasty and stenting relieves symptoms of extremity swelling and pain in the majority of treated patients. Existing data provide convincing proof of the efficacy of endovascular recanalization procedures, and upcoming prospective, controlled trials will further clarify the role of these techniques in the therapeutic armamentarium.

L-arginine improves endothelial vasoreactivity and reduces thrombogenicity after thrombolysis in experimental deep venous thrombosis

PURPOSE

Nitric oxide (NO) is important in regulation of platelet aggregation, endothelial function, and intravascular thrombosis. The purposes of this study were to assess the effect of thrombolysis on endothelial function in a porcine model of deep venous thrombosis (DVT) and to evaluate the effect of NO precursor l-arginine on endothelial function after thrombolytic therapy.

METHODS

DVT was created in bilateral iliac veins by deploying a self-expanding stent-graft that incorporated an intraluminal stenosis, from a groin approach. Five pigs underwent sham operation. After 7 days of DVT, animals were randomized to three groups: saline pulse-spray (saline group, n = 5), thrombolytic pulse-spray with tissue plasminogen activator (alteplase, 8 mg; t-PA group, n = 5), and thrombolytic pulse-spray plus intravenous l-arginine (20 mmol/L; arginine group, n = 5). At 2 weeks iliac vein patency was evaluated at venography and intravascular ultrasound scanning. NO level was determined with a chemiluminescent assay of the nitrite and nitrate metabolites (NO(x)). Thrombogenicity was evaluated with radiolabeled platelet and fibrin deposition. Veins were harvested and evaluated with light microscopy and scanning electron microscopy. Endothelial function was evaluated with organ chamber analysis.

RESULTS

All iliac veins remained patent at 2 weeks. The luminal areas in the sham, saline, t-PA, and arginine groups were 53 +/- 23 mm(2), 14 +/- 11 mm(2), 34 +/- 19 mm(2), and 42 +/- 21 mm(2), respectively. No difference in endothelial cell structure was observed between the three treatment groups at light microscopy or scanning electron microscopy. Although no difference in fibrin deposition was noted among the three treatment groups, decreased platelet deposition occurred in the arginine group compared with the saline or t-PA groups (P <.05). The arginine group showed greater endothelial-dependent relaxation compared with the t-PA or saline groups (73% +/- 23% vs 49% +/- 18% and 32% +/- 21%; P <.05). Local NO(x) level in the arginine group was correspondingly higher compared with the saline or t-PA groups (1.8 +/- 0.3 micromol/L vs 0.3 +/- 0.05 micromol/L and 0.2 +/- 0.04 micromol/L; P <.05).

CONCLUSIONS

NO precursor l-arginine supplementation enhances NO production at sites of venous thrombosis. Moreover, l-arginine preserves endothelial vasoreactivity and reduces platelet deposition after thrombolysis in iliac DVT. These data suggest that l-arginine may preserve endothelial function after thrombolysis and may reduce the likelihood of postthrombotic syndrome.

Luminal thrombus disrupts nitric oxide-dependent endothelial physiology

BACKGROUND

The goals of this study were: (1) to develop a large animal model to study endothelial function, and (2) to determine if arterial thrombosis induces endothelial dysfunction in vivo.

METHODS

Surgical exposure of the porcine iliac and femoral arteries was performed. Normal porcine arteries were compared with arteries subjected to 90 min of arterial thrombosis. External iliac artery (EIA) luminal diameters were measured using M- and B-mode duplex ultrasound. Endothelium-dependent relaxation (EDR) and endothelium-independent relaxation (EIR) were measured using acetylcholine (ACh) and sodium nitroprusside (NTP), respectively. Endothelial integrity was determined by factor VIII immunohistochemistry (F8) and scanning electron microscopy (SEM). Nitric oxide levels were determined using a chemiluminescence assay of nitrite/nitrate metabolites (NO(x)). Continuous variables were analyzed using the two-tailed Student t test.

RESULTS

Control artery EDR was 80 +/- 7.1% (+/- SE), while arteries exposed to luminal thrombus for 90 min had an EDR of 55.2 +/- 5.7% (ACh = 15 microg/min, n = 11, P = 0.0231). EIR was preserved in normal and thrombosis groups with uniform response to NTP (4.92 +/- 0.1 cm vs 5.07 +/- 0.42 cm, P = 0.76). F8 staining identified endothelium in all groups. SEM analysis revealed an intact monolayer of endothelium after thrombosis. Local NO(x) levels were 17.3% lower after 90 min of thrombosis (49.3 microM vs 40.8 microM, n = 16, P < 0.001).

CONCLUSIONS

Luminal thrombus induces arterial dysfunction acutely without causing endothelial cell loss. EIR remains unaffected, indicating normal smooth muscle cell function. NO(x) levels suggest that nitric oxide levels are decreased acutely after thrombosis. The development of this porcine large animal model allows the in vivo study of vasospasm and alternative thrombolytic regimens.

The effects of a mechanical thrombolytic device on normal canine vein valves

PURPOSE

To determine if the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) causes damage to normal vein valves.

MATERIALS AND METHODS

Ten lateral saphenous veins in five dogs were studied with descending venography with use of a wedge balloon catheter positioned above 48 valves (demonstrating 51 valves) before and after five antegrade passes each with an over-the-wire (0.025-inch), 6.5-F, 9-mm-diameter PTD. Vein diameters were 3.2-11.4 mm (mean, 5.9 mm). Contrast matter was injected at incremental rates from 3 to 15 mL/min during continuous pressure monitoring. Imaging was performed with digital subtraction angiography at a rate of 1 frame/sec. The time to valve reflux was determined by noting the frame at which reflux was first seen through the valve. The time to reflux and pressure required to reflux were compared before and after the PTD passes. All vessels were explanted and evaluated histologically for presence or absence of endothelial loss, thrombus formation, inflammation, or valve degeneration. Four veins in two animals were studied with venography to determine the variability of the venographic method. These veins thrombosed during venography and therefore served as positive pathologic controls. In two animals, one vein was studied with venography and one was not studied to provide pathologic controls.

RESULTS

With use of two physiologic tests of valve function, 77% of valves had minimal or no damage as assessed by valve competency and 80% had minimal or no damage as demonstrated by the change in the pressures the valve can withstand before reflux. Twenty-six of 51 valves (51%) had no difference or later reflux after PTD use. Thirteen (26%) refluxed 1 second earlier after PTD use and 12 (23%) refluxed > or =2 seconds earlier (six at 2, four at 3, and two at 4). Four of the six valves with more than a 2-second difference in reflux times were in valves with diameters less than 4.2 mm. All these vessels were smaller than 7 mm in diameter. Twenty-one of 48 valve levels (44%) had no difference or sustained higher pressures before reflux after PTD use. Seventeen (36%) had a pressure drop of <10 mm Hg; five (10%) had drops of 12-24 mm Hg; and five (10%) had drops of more than 40 mm Hg. There was a significant difference in endothelial loss, thrombus formation, and inflammation between experimental veins, the veins with thrombus, the venography controls, and the normal vein controls. There was significant difference only in terms of inflammation when the experimental group was compared to the thrombosis group.

CONCLUSION

The antegrade use of the PTD across normal canine vein valves does not cause physiologically significant damage in valves 7 mm or larger in diameter in this animal model.

Thrombolysis for experimental deep venous thrombosis maintains valvular competence and vasoreactivity

PURPOSE

Thrombolysis protects the structural and functional integrity of vein wall in an experimental model of acute deep venous thrombosis (DVT) immediately after treatment, but late sequelae have not been studied. We designed experiments to compare the effects of thrombolysis and surgical thrombectomy at 4 weeks after the treatment of DVT.

METHODS

DVT was produced bilaterally in male mongrel dogs by proximal and distal femoral vein ligation. Five dogs underwent sham operation. After 48 hours, the ligatures were removed, and the thrombosis was treated with either Fogarty balloon catheter thrombectomy (shear force, 60 g; n = 6) or catheter-directed urokinase infusion (4000 U/min for 90 minutes; n = 6). At 4 weeks, patency and valvular competence were determined by duplex ultrasound scanning. Thrombogenicity was studied by the measurement of radiolabeled fibrin and platelet deposition. Veins were explanted and prepared for histologic examination, scanning electron microscopy, and functional studies in organ chambers.

RESULTS

All veins were patent at 1 month. Recanalized thrombus was observed histologically in four (66%) thrombectomized veins, one (17%) thrombolyzed vein, and none of the sham-operated veins (P =.04). Scanning electron microscopy demonstrated similar luminal endothelial cell loss (11%-25%) in all three groups. Platelet and fibrin depositions were not different among groups. Valvular incompetence (reflux duration, >0.5 sec) did not differ significantly in the groups (thrombectomized veins, 2 of 12 (17%); thrombolyzed veins, 0 of 12 (0%); P = NS). In organ chamber studies, endothelium-dependent relaxations to calcium ionophore, but not adenosine diphosphate, were inhibited by an antagonist of nitric oxide production after thrombectomy (P <.05, thrombectomy vs sham- and thrombolysis-treated veins). All veins relaxed to exogenous nitric oxide.

CONCLUSION

Both thrombectomy and thrombolysis restored patency and achieved similar valvular competence. Surgical thrombectomy, however, resulted in more residual thrombus and contributed to changes in endothelium-mediated relaxations at 4 weeks. Thrombolysis maintained both structural integrity and endothelial function.