Percutaneous mechanical thrombectomy to remove post-thrombotic obstructions and manage post-thrombotic syndrome-associated venous leg ulceration.

BACKGROUND: Up to one half of patients with a diagnosis of deep vein thrombosis will develop post-thrombotic syndrome (PTS). Patients with PTS can develop venous leg ulcers (VLUs) due to post-thrombotic obstructions (PTOs) that contribute to prolonged ambulatory venous hypertension. The current treatments for PTS, which include chronic thrombus, synechiae, trabeculations, and inflow lesions, do not target PTOs, and such obstructions can affect stenting success. The aim of the present study was to determine whether removal of chronic PTOs using percutaneous mechanical thrombectomy would promote VLU resolution and positive outcomes. METHODS: In this retrospective analysis, the characteristics and outcomes for patients with VLUs secondary to chronic PTO who were treated using the ClotTriever System (Inari Medical) between August 2021 and May 2022 were assessed. Technical success was considered the ability to cross a lesion and introduce the thrombectomy device. Clinical success was defined as a decrease of ≥1 in the severity category for the ulcer diameter using the revised venous clinical severity score (score 0, no VLU; score 1, mild VLU [size <2 cm]; score 2, moderate VLU [size 2-6 cm]; score 3, severe VLU [size >6 cm]) at the latest follow-up visit. RESULTS: A total of 11 patients with 15 VLUs on 14 limbs were identified. Their mean age was 59.7 ± 11.8 years, and four patients (36.4%) were women. The median VLU duration was 11.0 months (interquartile range [IQR], 6.0-17.0 months), and 2 patients had VLUs secondary to a deep vein thrombosis event >40 years previously. All treatments were performed in a single session, with technical success achieved in 100% of the 14 limbs. A median of five passes (IQR, four to six passes) with the ClotTriever catheter were performed per limb. Chronic PTOs were successfully extirpated, and intraprocedural intravascular ultrasound showed effective disruption of venous synechiae and trabeculations. Stents were placed in 10 limbs (71.4%). The time to VLU resolution or the latest follow-up was 12.8 ± 10.5 weeks, and clinical success was achieved for all 15 VLUs (100%), with the revised venous clinical severity score for the ulcer diameter improving from a median of 2 (IQR, 2-2) at baseline to a median score of 0 (IQR, 0-0) at last follow-up. The VLU area had decreased by 96.6% ± 8.7%. Of the 15 VLUs, 12 (80.0%) had resolved completely, and 3 had demonstrated near-complete healing. CONCLUSIONS: All patients showed complete or near-complete VLU healing within a few months after mechanical thrombectomy. Mechanical extirpation and interruption of chronic PTOs allowed for luminal gain and restoration of cephalad inflow. With additional investigation, mechanical thrombectomy with the study device could prove a vital component to the treatment of VLUs secondary to PTOs.

Meta-analysis of lytic catheter-based intervention for acute proximal deep vein thrombosis in the reduction of post-thrombotic syndrome.

OBJECTIVE: Post-thrombotic syndrome (PTS) is a common complication of deep vein thrombosis (DVT) that can result in significant morbidity for the patient with detrimental impact on their quality of life. Evidence supporting lytic catheter-based interventions (LCBI) undertaken for early thrombus reduction in acute proximal DVT for the prevention of PTS is conflicting. Despite this, rates of LCBIs are increasing. To summaries the existing evidence and pool treatment effects, a meta-analysis of randomized controlled trials assessing the efficacy of LCBIs in proximal acute DVT for the prevention of PTS was undertaken. METHODS: This meta-analysis was undertaken aligning with PRISMA guidelines following a protocol pre-registered on PROSPERO. Online searches of Medline and Embase databases, as well as the gray literature, were performed up to December 2022. Included articles were randomized controlled trials that studied the use of LCBIs with additional anticoagulation vs anticoagulation alone and had determined follow-up periods. Outcomes of interest were PTS development, moderate to severe PTS, major bleeding episodes, and quality-of-life measures. Subgroup analyses were performed for DVTs involving the iliac vein and/r common femoral vein. Meta-analysis was performed using a fixed effects model. Quality assessment was performed using the Cochrane Risk of Bias and GRADE assessment tools. RESULTS: Three trials were included in the final meta-analysis, the Post-thrombotic Syndrome after Catheter-directed Thrombolysis for Deep Vein Thrombosis (CaVenT), Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis (ATTRACT), and Ultrasound-accelerated Catheter-directed Thrombolysis Versus Anticoagulation for the Prevention of Post-thrombotic Syndrome (CAVA) trials, comprising 987 patients. Patients undergoing LCBIs had a reduced risk of PTS (relative risk [RR], 0.84; 95% confidence interval [CI], 0.74-0.95; P = .006) and a lower risk of developing moderate to severe PTS (RR, 0.75; 95% CI, 0.58-0.97; P = .03). LBCIs increased the risk of having a major bleed (RR, 2.03; 95% CI, 1.08-3.82; P = .03). In the iliofemoral DVT subgroup analysis, there was a trend toward decreasing the risk of developing PTS and moderate to severe PTS (P = .12 and P = .05, respectively). There was no significant difference in quality-of-life score (as measured by the Venous Insufficiency Epidemiological and Economic Study - Quality of Life/Symptoms) between the two groups (P = .51). CONCLUSIONS: Pooling of current best evidence suggests that LCBIs in acute proximal DVT decreases the rate of PTS and moderate to severe PTS with a number needed to treat of 12 and 18, respectively. However, this is complicated by a significantly higher rate of major bleeding with a number needed to treat of 37. This evidence supports the use of LCBIs in selected patients, including those who are at low risk of major bleeding.

Developing and optimizing a machine learning predictive model for post-thrombotic syndrome in a longitudinal cohort of patients with proximal deep venous thrombosis.

BACKGROUND: Post-thrombotic syndrome (PTS) is the most common chronic complication of deep venous thrombosis (DVT). Risk measurement and stratification of PTS are crucial for patients with DVT. This study aimed to develop predictive models of PTS using machine learning for patients with proximal DVT. METHODS: Herein, hospital inpatients from a DVT registry electronic health record database were randomly divided into a derivation and a validation set, and four predictive models were constructed using logistic regression, simple decision tree, eXtreme Gradient Boosting (XGBoost), and random forest (RF) algorithms. The presence of PTS was defined according to the Villalta scale. The areas under the receiver operating characteristic curves, decision-curve analysis, and calibration curves were applied to evaluate the performance of these models. The Shapley Additive exPlanations analysis was performed to explain the predictive models. RESULTS: Among the 300 patients, 126 developed a PTS at 6 months after DVT. The RF model exhibited the best performance among the four models, with an area under the receiver operating characteristic curves of 0.891. The RF model demonstrated that Villalta score at admission, age, body mass index, and pain on calf compression were significant predictors for PTS, with accurate prediction at the individual level. The Shapley Additive exPlanations analysis suggested a nonlinear correlation between age and PTS, with two peak ages of onset at 50 and 70 years. CONCLUSIONS: The current predictive model identified significant predictors and accurately predicted PTS for patients with proximal DVT. Moreover, the model demonstrated a nonlinear correlation between age and PTS, which might be valuable in risk measurement and stratification of PTS in patients with proximal DVT.

Double-barrel iliocaval reconstruction using closed-cell dedicated venous stents.

OBJECTIVE: Double-barrel iliocaval reconstruction is performed by deploying two stents simultaneously in a side-by-side, or "double-barrel," configuration in the inferior vena cava (IVC) with extension into the bilateral common iliac veins. The aim of this study was to examine the outcomes of double-barrel reconstruction using closed-cell dedicated venous stents for the treatment of iliocaval deep venous thrombosis and iliac vein compression syndrome. METHODS: All endovascular procedural reports comprising vascular surgery and interventional radiology operators from a single urban academic hospital between May 1, 2019, and April 30, 2021, were retrospectively searched. A cohort of 22 consecutive patients who underwent double-barrel iliocaval stenting with closed-cell dedicated venous stents for chronic or acute-on-chronic iliocaval venous disease without prior endovascular iliocaval repair was identified. Baseline characteristics, procedural data, and patient outcomes were determined via a manual review of preprocedure clinical notes, diagnostic imaging studies, procedure notes and images, and follow-up clinical notes. RESULTS: The median (range) age was 59 (27-81) years, and the cohort consisted of 59.1% female. The most common presenting symptoms of venous disease were lower extremity swelling (90.9%) and pain (50.0%). CEAP clinical classification was C3 in 86.4% of patients, whereas the remainder had C4 disease. Most patients (72.7%) had post-thrombotic syndrome, 22.7% had a nonthrombotic iliac vein lesion, and one patient (4.5%) had the congenital absence of the infrarenal IVC. A total of 40.9% of patients had a pre-existing IVC filter at the time of treatment. Six of the 22 patients underwent concurrent pharmacomechanical thrombectomy during the index iliocaval reconstruction and stenting procedure. The number of stents placed ranged from 2 to 5. With a mean follow-up period of 7.1 months, ranging from 12 days to 16.7 months, the freedom from reintervention rate was 90.9%. Twenty of 22 patients achieved subjective improvement or resolution of symptoms. The major adverse event rate was 9.1%, as two patients had access site complications requiring intervention. CONCLUSIONS: Double-barrel iliocaval reconstruction with closed-cell dedicated venous stents for the treatment of post-thrombotic syndrome or iliac vein compression syndrome is technically feasible and clinically effective with a low reintervention rate.

Risk factors and classification of reintervention following deep venous stenting for acute iliofemoral deep vein thrombosis.

BACKGROUND: Acute iliofemoral deep vein thrombosis (DVT) is associated with the development of post-thrombotic syndrome (PTS). Thrombolysis and deep venous stenting can restore vessel outflow and can reduce the incidence of PTS. However, for a proportion of patients, subsequent stenosis or reocclusion will necessitate further intervention. In the present study, we aimed to identify the risk factors, examine the outcomes (reintervention success and PTS), and develop a classification system for reintervention. METHODS: A retrospective single-center cohort study of patients who had undergone successful lysis for iliofemoral DVT from 2013 to 2017. The patients' records and imaging studies were examined for demographics, risk factors, extent of thrombus and vessel clearance, stenting, flow, reintervention, anticoagulation compliance, Villalta score, and secondary patency. From our findings, a system of classification for patients for whom procedures have failed was developed, constituting technical, hematologic, flow related, or multiple factors. RESULTS: Of 143 limbs (133 patients), 48 (33.6%) had required reintervention, of which 25 had presented with reocclusion (17.4%). The median time to reintervention was 45 days. The need for reintervention was associated with inferior vena cava thrombus (risk ratio [RR], 2.16; P < .01), stenting across the inguinal ligament (RR, 2.08; P < .01), and anticoagulation noncompliance (RR, 7.09; P < .01). Successful reintervention was achieved in 31 limbs (64.6%): 23 of 23 (100%) treated before occlusion vs 8 of 25 (36.4%) treated after occlusion (RR, 32.31; P < .01). A greater incidence of any PTS was observed for patients requiring reintervention (median Villalta score, 3 [interquartile range, 1-5]; vs 1 [interquartile range, 1-4]; RR, 2.28; P = .029). Cases without complete vessel occlusion (reintervention and control) had a lower rate of any PTS (14.0% vs 42.9%; RR, 3.06; P < .01) and moderate to severe PTS (3.0% vs 14.3%; RR, 4.76; P = .046) Technical issues were observed in 54.2% of reintervention cases and 6.3% of cases not requiring reintervention (P < .01). Hematologic issues were identified in 33.3% of reintervention cases and 1.1% of cases not requiring reintervention (P < .01). Flow-related issues were observed in 43.8% of the reintervention cases and no cases not requiring reintervention (P < .01). Of the reintervention cases, 27.1% were multifactorial and were associated with a lower rate of vessel salvage; however, this did not translate into a significant difference in secondary patency on survival analysis (RR, 1.70; P = .429). CONCLUSIONS: A large proportion of patients required reintervention because of potentially preventable factors. Anticoagulation compliance, thrombus burden, and poor flow are important risk factors to consider in patient selection. Reintervention increased the risk of PTS and was more often successful when achieved before vessel occlusion.

Interim outcomes of mechanical thrombectomy for deep vein thrombosis from the All-Comer CLOUT Registry.

OBJECTIVES: The multicenter, prospective, single arm CLOUT registry assesses the safety and effectiveness of the ClotTriever System (Inari Medical, Irvine, CA) for the treatment of acute and nonacute lower extremity deep vein thrombosis (DVT) in all-comer patients. Reported here are the outcomes of the first 250 patients. METHODS: All-comer patients with lower extremity DVT were enrolled, including those with bilateral DVT, those with previously failed DVT treatment, and regardless of symptom duration. The primary effectiveness end point is complete or near-complete (≥75%) thrombus removal determined by independent core laboratory-adjudicated Marder scores. Safety outcomes include serious adverse events through 30 days and clinical outcomes include post-thrombotic syndrome severity, symptoms, pain, and quality of life through 6 months. RESULTS: The median age was 62 years and 40% of patients had contraindications to thrombolytics. A range of thrombus chronicity (33% acute, 35% subacute, 32% chronic) was observed. No patients received thrombolytics and 99.6% were treated in a single session. The median thrombectomy time was 28 minutes. The primary effectiveness end point was achieved in 86% of limbs. Through 30 days, one device-related serious adverse event occurred. At 6 months, 24% of patients had post-thrombotic syndrome. Significant and sustained improvements were observed in all clinical outcomes, including the Revised Venous Clinical Severity Score, the numeric pain rating scale, and the EuroQol Group 5-Dimension Self-Report Questionnaire. CONCLUSIONS: The 6-month outcomes from the all-comer CLOUT registry with a range of thrombus chronicities demonstrate favorable effectiveness, safety, and sustained clinical improvements.

Hybrid operative thrombectomy is noninferior to percutaneous techniques for the treatment of acute iliofemoral deep venous thrombosis.

OBJECTIVE: Hybrid operative thrombectomy (HOT) is a novel technique for the treatment of acute iliofemoral deep venous thrombosis (IFDVT) and is an alternative to percutaneous techniques (PTs) that use thrombolytics. In this study, we compare perioperative and intermediate outcomes of HOT vs PT as interventions for early thrombus removal. METHODS: From July 2008 to May 2015, there were 71 consecutive patients who were treated with either PT (n = 31) or HOT (n = 40) for acute or subacute single-limb IFDVT. HOT consisted of surgical thrombectomy with balloon angioplasty with or without stenting by a single incision and fluoroscopically guided retrograde valve manipulation to extract the thrombus. PT included catheter-directed thrombolysis with or without pharmacomechanical thrombectomy using the Trellis-8 system (Bacchus Vascular, Santa Clara, Calif). Patients who presented with bilateral DVT (n = 4), inferior vena cava involvement (n = 8), or venous gangrene (n = 1) were excluded. Perioperative outcomes, quality measures, and thrombus resolution were compared between the two treatment groups. Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) classification, Villalta score, and venous duplex ultrasound at intermediate follow-up were also analyzed. RESULTS: The left limb was the most common site of the IFDVT overall. Technical success (≥50% resolution) was 100% for both groups, and >80% resolution was achieved in all patients treated with HOT. There were eight major bleeding events in the PT group compared with three in the HOT group (P = .04). PT patients had a significantly longer length of stay (13 vs 10 days; P = .028) compared with HOT. At 2-year duplex ultrasound examination, there was no difference between HOT and PT in mean reflux times at the femoral-popliteal segment. At 2 years, 85% and 87% of the patients (HOT vs PT, respectively) had not developed post-thrombotic syndrome, and there was no difference between the groups for mean Villalta score (2.1 ± 1.9 vs 2.3 ± 2; P = .79). CONCLUSIONS: PT and HOT have demonstrated good outcomes in the perioperative and intermediate periods. HOT is noninferior to PT as a technique for early thrombus removal and has the advantages that thrombus resolution is established in one operation and length of stay is significantly decreased. HOT avoids thrombolytic therapy, which may reduce major bleeding events.

Is the fibrotic parietal thickening a reliable parameter for diagnosing previous asymptomatic deep vein thrombosis?

AIM: Research of a starting point to debate about the possibility of identifying a unique sign of previous DVT. MATERIAL OF STUDY: A retrospective study involving 202 outpatients with venous insufficiency of the lower limbs (CEAP classes C 4/6), classified according to the affected venous district. Patients positive for deep vein thrombosis (DVT) were subjected to Compression Ultra Sound test (CUS test) with measurement of the wall thickness at the point of formation of the thrombus and at fixed points of common femoral and popliteal veins used also in the patients with negative history of DVT RESULTS: Among total group, only 19 patients (9.40%) had an history of DVT. No one of them had a superficial incontinence. The measurement of wall thickness in positive DVT history patients (group A) resulted in an average value of 1.10 mm (s.d=0.06), while the average value obtained in negative DVT history (group B) was 0.55 mm (s.d.= 0.20). However, in 13 patients wall thickness was > 1mm (mean: 1.04 mm). The difference between the averages of group A and B was statistically significant (p <0.05). DISCUSSION: In all positive DVT history patients and in 13 ones with negative history we found an increase in wall thickness, with a value > 1 mm. Can the wall thickening more than 1 mm be considered an indicator of previous DVT? Can it be considered a "marker" for thrombophilia status? CONCLUSIONS: The usefulness of a sign of previous DVT (even if asymptomatic), detected during a routine Doppler ultrasound check of lower limbs, could be a warning bell to investigate thrombophilia status. KEY WORDS: Chronic Venous Insufficiency, Duplex ultrasound, Hypercoagulability, Post-thrombotic Syndrome, Venous Thromboembolism.

How to predict and diagnose postthrombotic syndrome.

Postthrombotic syndrome (PTS) is the most frequent complication of deep vein thrombosis (DVT). From 20% to 50% of the patients will develop PTS after DVT, and from 5% to 10%, severe PTS. PTS is diagnosed on clinical grounds, based on the presence of signs and symptoms of venous insufficiency in the leg ipsilateral to DVT. The Villalta scale, a clinical scale that incorporates venous symptoms and signs, is a recommended standard for the diagnosis of PTS. Identifying which patients are at high risk of developing PTS would help improve the management of patients with DVT and allow physicians to provide patients with individualized information on their expected prognosis. Clinical predictors of PTS have been progressively characterized, but the ability to predict which patient with DVT is likely to develop PTS remains limited. A number of risk factors for PTS have been identified; of these, proximal location of DVT and a previous ipsilateral DVT are the most important. This review discusses the knowledge gained over the last decade on the diagnosis and predictors of PTS.  

Predictors of the post-thrombotic syndrome with non-invasive venous examinations in patients 6 weeks after a first episode of deep vein thrombosis.

BACKGROUND: Post-thrombotic syndrome (PTS) is a chronic complication of deep vein thrombosis (DVT) affecting a large number of patients. Because of its potential debilitating effects, identification of patients at high risk for the development of this syndrome is relevant, and only a few predictors are known. OBJECTIVES: To assess the incidence and potential predictors of PTS. METHODS: We prospectively followed 111 consecutive patients for 2 years after a first episode of objectively documented DVT of the leg. With non-invasive venous examinations, residual thrombosis, valvular reflux, calf muscle pump function and venous outflow resistance were assessed at 6 weeks, 3 months, 6 months, 1 year, and 2 years. The Clinical, Etiologic, Anatomic, and Pathophysiologi classification was used to record the occurrence and severity of PTS. Regression analysis with area under the receiver operating characteristic (ROC) curve was performed to identify potential predictors. RESULTS: The cumulative incidence of PTS was 46% after 3 months, and the incidence and severity did not increase further. Men appeared to be at increased risk as compared with women (risk ratio [RR] 1.4, 95% confidence interval [CI] 0.9-2.2), as were patients over 50 years as compared with younger patients (RR 1.4%, 95% CI 0.9-2.1). Patients with thrombosis localized in the proximal veins at diagnosis had an increased risk of PTS as compared with patients with distal thrombosis (RR 2.3%, 95% CI 1.0-5.6). PTS developed in 32 of 52 patients (62%) with residual thrombosis in the proximal veins 6 weeks after diagnosis, as compared with 17 of 45 patients (38%) without residual proximal thrombosis, leading to a 1.6-fold increased risk (95% CI 1.0-2.5). The presence of valvular reflux in the superficial veins was also a predictor at 6 weeks, with a 1.6-fold increased risk as compared with patients without superficial reflux (95% CI 1.1-2.3). A multivariate analysis of these predictors yielded an area under the ROC curve of 0.72 (95% CI 0.62-0.82). CONCLUSIONS: PTS develops in half of all patients within 3 months, with no further increase being seen up to 2 years of follow-up. Male sex, age over 50 years, proximal localization of the thrombus at entry, residual proximal thrombosis and superficial valvular reflux at 6 weeks seem to be the most important predictors of PTS in patients with a first episode of DVT. Duplex scanning 6 weeks after diagnosis appears to be clinically useful for the identification of patients at risk of PTS.

Contemporary issues in the prevention and management of postthrombotic syndrome.

OBJECTIVE: To provide an evidence-based review and clinical summary of postthrombotic syndrome (PTS). DATA SOURCES: A literature review was performed via MEDLINE (1950-July 1, 2009) and International Pharmaceutical Abstracts (1970-June 2009) searches using the terms post-thrombotic syndrome, post-phlebitic syndrome, deep vein thrombosis, and compression stockings. DATA SYNTHESIS: PTS is best characterized as a chronic syndrome of clinical signs and symptoms including pain, swelling, parasthesias, and ulceration in the affected limb following deep vein thrombosis (DVT). It occurs in up to half of patients with symptomatic DVT, usually within the first 2 years. Although the pathophysiology of PTS is not well understood, a thrombus may cause venous hypertension and valvular incompetence resulting in edema, tissue hypoxia, and in severe cases, ulceration. Risk factors for PTS include recurrent ipsilateral DVT, obesity, and poor quality of anticoagulant therapy. PTS diagnosis is based on the presence of typical signs and symptoms and may be made using one of several clinical scoring systems. Prevention of PTS should focus on DVT prevention and the use of elastic compression stockings following DVT, while fibrinolysis remains under investigation as an effective method for PTS prevention. The treatment of PTS may include either pharmacologic or mechanical modalities, although none of these regimens has been rigorously tested. Pharmacists have the opportunity to provide more comprehensive antithrombotic management by educating patients and providers on PTS, recommending appropriate preventive therapy, assisting patients in obtaining and adhering to this therapy, and assisting providers with the management of PTS. CONCLUSIONS: Providers should be proactive in preventing PTS, with pharmacists taking an active role in optimal DVT prevention, identifying patients at risk for PTS, and counseling and directing preventive therapies.

[Treatment of postoperative thrombosis]. / Therapie der postoperativen Thrombose.

For the treatment of deep vein thrombosis (DVT), rapid diagnosis and prompt therapy are crucial to minimize the risk of fatal pulmonary embolism and long-term complications, including the postthrombotic syndrome and recurrent thromboembolism. The treatment of acute DVT remains controversial. In this review, treatment options in relation to exposing and predisposing risk factors are discussed. Evidence-based data and recommendations from official guidelines are presented.

Lower extremities' postthrombotic syndrome after total knee arthroplasty.

BACKGROUND: Deep venous thrombosis (DVT) is a disease associated with high morbidity in 40-60% patients who underwent Total Knee Arthroplasty (TKA). Postthrombotic syndrome (PTS) is a common long-term complication that may develop within 6 months or more than 2 years after episode of DVT. OBJECTIVE: To examine the prevalence of PTS in patients who had history of previous DVT and non-previous DVT at least 2-year follow-up period after TKA. MATERIAL AND METHOD: Retrospective chart review was done. All patients who underwent TKA during October 2002-2005 were included. They were postoperatively assessed for PTS with Villalta score and duplex ultrasonography at > or =2 years. The confirmed diagnosis of DVT was done by contrast venography. RESULTS: 22 of 76 patients (56 previous DVT 20 non-previous DVT) had PTS based on the clinical assessment. The previous-DVT group had significantly higher risk to PTS (OR = 1.59; 95% CI: 1.294-1.949; p-value = 0.001). When diagnosed with duplex ultrasonography, 36 in 56 patients of previous-DVT group and 8 in 20 of non-previous-DVT group were found positive venous reflux. Most of venous reflux occurred at popliteal vein (77%) and posterior tibial vein (59%). CONCLUSION: After TKA, the patients who developed DVT had higher risk to PTS (OR = 1.588). Treatment of DVT may not decrease this risk. Prevention of DVT becomes an important approach to prevent PTS.

Post-thrombotic syndrome after total hip arthroplasty is uncommon.

BACKGROUND: Deep vein thrombosis (DVT), usually asymptomatic, is common after total hip arthroplasty (THA). Post-thrombotic syndrome (PTS) is a potential late complication of DVT, but there is limited data on its occurrence. PATIENTS AND METHODS: This was a prospective cohort study of subjects at one hospital who had participated in a trial of thromboprophylaxis for THA and who had postoperative venography. Data were collected at baseline and 2-4 years later to ascertain symptoms of PTS using a modification of a validated scoring system. Outcomes were collected without knowledge of baseline characteristics or venogram results. Potential predictors of PTS were explored using exact logistic regression analyses. RESULTS: The cohort (n=188) had a mean age of 63 years, 51% were male, 35% had a BMI of>30, and 4% had a prior history of DVT. 25 patients (13%) had DVTs on venography. 12 patients (6%, 95% CI: 3-11) subsequently developed symptoms consistent with PTS, 7 with bilateral symptoms. Most affected limbs (15 of 19) had no postoperative DVT. No statistically significant predictors of PTS were found. INTERPRETATION: Symptoms of PTS are infrequent after THA in patients who receive some form of thromboprophylaxis. Our findings, which are consistent with the existing literature, suggest that there is a potential benefit to giving thromboprophylaxis for reduction of symptomatic PTS.

Postthrombotic or non-postthrombotic severe venous insufficiency: impact of removal of superficial venous reflux with or without subcutaneous fasciotomy.

BACKGROUND: Severe chronic venous insufficiency is often associated with therapy-resistant or recurrent venous leg ulcers, either as a result of deep vein thrombosis (DVT)- (postthrombotic syndrome [PTS]) or superficial venous insufficiency (SVI). Frequently present dermatoliposclerosis affects the skin as well as the subcutaneous and subfascial structures, which may impact tissue pressures and compromise skin perfusion. This study was undertaken to measure tissue pressures in PTS and SVI limbs and to evaluate the impact of removal of superficial venous reflux with or without concomitant subcutaneous fasciotomy. MATERIAL: In eight patients with recurrent, therapy-resistant venous leg ulcers, due to PTS (11 limbs, 12 ulcers) and 14 patients with severe SVI (14 limbs, 14 ulcers), subcutaneous fasciotomy was performed in addition to removal of superficial reflux. They were compared with eight patients with PTS (11 limbs, 11 ulcers) and 10 patients with SVI (13 limbs, 13 ulcers) who did not have fasciotomy in addition to removal of their superficial venous reflux. Intramuscular (i.m.) and subcutaneous (s.c.) tissue pressures and transcutaneous oxygen tension (TcPO(2)) were measured prior to, immediately after, and 3 months following the surgical intervention. Healing of ulcer (spontaneous or by skin grafting) at 3 months was also observed. RESULTS: There were no statistical differences between the groups regarding gender and age distribution or ulcer age at the time of surgery. All patients had in addition to surgery compression stockings class II (30 mm Hg). The i.m. tissue pressure was higher in patients with PTS compared with SVI patients, while s.c. tissue pressure and TcPO(2) did not differ between the groups. When fasciotomy was performed, i.m. and s.c. tissue pressures decreased and TcPO(2) increased significantly. Without fasciotomy, only s.c. tissue pressure decreased first at 3 months postoperatively. In the SVI-group, i.m tissue pressure was significantly decreased at 3 months in the group without fasciotomy. CONCLUSIONS: Patients with severe chronic venous insufficiency with therapy-resistant or recurrent ulcer disease due to deep and superficial insufficiency have higher i.m. tissue pressures than patients with only superficial venous reflux, even though both groups have higher i.m. and s.c. tissue pressures compared with normal values. Eradication of all superficial reflux lowers s.c. tissue pressure, while additional fasciotomy lowers both i.m. and s.c. tissue pressures and increases TcPO(2), which seems to promote ulcer healing.

Molecular characterization of post-thrombotic syndrome.

The post-thrombotic syndrome represents a poorly understood and significant vascular health problem. This review focuses on our current understanding of the pathogenesis of post-thrombotic syndrome. We emphasize the cellular and molecular mechanisms that are responsible for the critical components of post-thrombotic syndrome. These include the initiation of deep venous thrombosis, the pathogenesis of elevated venous pressure, and the factors responsible for nonhealing of venous stasis ulcers.

High peak reflux velocity in the proximal deep veins is a strong predictor of advanced post-thrombotic sequelae.

BACKGROUND: The presence of reflux in the femoral vein (FV) and popliteal vein (POPV) after acute deep vein thrombosis (DVT) is considered to contribute to the development of advanced post-thrombotic syndrome (PTS). However, a quantification of reflux has yet to be determined. The purpose of study was to determine the indicative parameters reflecting the progression of PTS. METHODS: Venous abnormalities were evaluated in 131 limbs out of 130 patients who completed a six-year follow-up after an acute DVT. Clinical manifestations were categorized according to the clinical, etiologic, anatomic, and pathophysiologic (CEAP) classification, and the patients were divided into two groups at a six-year follow-up point: group I, C(0-3)E(s),A(s,d,p),P(r,o), early chronic venous insufficiency (CVI); group II, C(4-6)E(s),A(s,d,p),P(r,o), advanced CVI. Venous segments were examined whether they were occluded or recanalized. The reflux parameters assessed were the diameter (cm), the reflux time (RT; s), the peak reflux velocity (PRV; cm s(-1)), and total refluxed volume, and these parameters were assessed especially in the FV and POPV at the two-year (early phase) and subsequent six-year (late phase) follow-up points after DVT. RESULTS: There were 98 limbs in group I and 33 in group II. The frequency of venous reflux was significantly higher in group II (<0.0001). In contrast, the proportion of occlusion did not differ between the groups (P = 0.138). The proportions of FV and POPV incompetence were significantly higher in group II (P < 0.0001 and P < 0.0001, respectively). In these veins, the RT did not improve the discrimination power between the two groups. In contrast, the PRV had significant discrimination power in these veins at both the two- and six-year follow-up points. In the superficial venous system, there were no significant differences in any of the determined parameters between the groups. In group II, 19 patients (58%), who had early symptoms of CVI at the two-year follow-up point, subsequently developed advanced symptoms of PTS. After calculating a suitable cutoff point using receiver operating characteristic curves analysis at the two-year follow-up point, multivariable analysis showed that a PRV of >25.4 cm s(-1) in the POPV was the strongest independent predictor of advanced CVI [odds ratio (OR) 60.32; 95% confidence interval (95CI) 43.1-1238.97, P < 0.0001]. Similarly, in the FV, a PRV of >24.5 cm s(-1) was found to be a strong predictor of advanced CVI (OR 25.77, 95CI 10.56-331.12, P < 0.0001). CONCLUSIONS: These findings suggest that the presence of a high PRV in the proximal deep veins is an independent predictor of advanced symptoms of PTS.

New technology applications: thrombolysis of acute deep vein thrombosis.

Treatment of deep vein thrombosis traditionally has focused on preventing the potentially life-threatening complication of pulmonary embolism rather than on removing or reducing the thrombus. Although treatment with anticoagulants may prevent thrombus propagation, the body's intrinsic thrombolytic system is left to attempt clot dissolution. Because this natural process is generally ineffective in its ability to fully recanalize a proximal vein, the risks of recurrent thrombosis as well as the disabling complication of postthrombotic syndrome increase. Moreover, the long-term consequences of postthrombotic syndrome include pain, disability, and, for many, a significant decrease in the quality of life. Recent technology using high-frequency, low-power ultrasound, or mechanical thrombectomy with catheter-directed delivery of a thrombolytic drug directly into the clot is available and showing promise. Nurses are caring for patients who receive endovascular interventions with lytic infusions. The nursing challenge is to provide safe and effective patient care.

Frequency and determinants of the postthrombotic syndrome after venous thromboembolism.

PURPOSE OF REVIEW: Postthrombotic syndrome (PTS) is the most common complication of deep venous thrombosis (DVT). Identifying which patients are at high risk of developing PTS would help improve the management of patients with DVT and allow physicians to provide patients with individualized information on their expected prognosis. This review discusses the knowledge gained from key studies over the last decade on the incidence and determinants of PTS, with special emphasis on published studies from the last 2 years. RECENT FINDINGS: About a third to half of DVT patients will develop PTS, in most cases within 1-2 years of acute DVT. Important risk factors for PTS appear to be ipsilateral recurrence of DVT, poor quality of initial anticoagulation for the treatment of DVT and increased body mass index. SUMMARY: Preventing DVT recurrence by providing adequate intensity and duration of anticoagulation for the initial DVT and using effective thromboprophylaxis in high-risk settings is likely to reduce the frequency of PTS. Despite some advances in identifying risk factors for PTS, however, it is still not possible to reliably predict an individual patient's risk of developing PTS after an episode of DVT. Further studies of clinical determinants and biological markers of increased risk of PTS are needed to ultimately improve long-term prognosis after DVT.