Deep vein thrombosis: pathogenesis, diagnosis, and medical management

Lymphatic Vessel Thrombosis in a Patient with Secondary Lymphedema

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Lymphatic thrombosis is rarer than venous thrombosis. This case report describes a patient with secondary lymphedema, who was found to have lymphatic thrombosis during lymphaticovenous anastomosis (LVA). A 51-year-old woman underwent hysterectomy and pelvic lymph node dissection for uterine cancer when she was 48 years old, and lymphedema developed in the left leg soon after the operation. She was diagnosed with lymphedema based on lymphoscintigraphic finding. Preoperative echography showed 2 hypoechoic circles measuring about 0.5 mm in diameter that did not collapse with pressure from the probe, although the veins collapsed with pressure. We diagnosed the 2 hypoechoic circles as lymphatic vessels based on the location and longitudinal continuity. During LVA, we identified 2 parallel white vessels beneath the superficial fascia. After they were cut, white material was extruded. A diagnosis of lymphatic thrombosis was made, and we ligated the lymphatic vessels, closed the wound at this site, and performed LVA at other sites (4 sites in the left and 1 site in the right leg). The postoperative course was uneventful. Histopathological examination showed hyperplasty of fibroblasts and organization in the thrombus. Lymphatic thrombosis is sometimes found in the lymphedema-affected extremities. On retrospective consideration, lymphatic thrombosis can be detected with preoperative echography.

A novel risk assessment model for venous thromboembolism after major thoracic surgery: a Chinese single-center study

Background

Venous thromboembolism (VTE) is an insidious disease with significant morbidity and mortality. We conducted a retrospective single-center study on patients who underwent thoracic surgery and developed a novel VTE risk assessment model (RAM).

Methods

Patients who underwent thoracic surgery between July 2016 and December 2017 (n=533) at the Beijing Chao-Yang Hospital were enrolled in this study. None of the patients received any prophylaxis perioperatively. Lower limbs Doppler ultrasonography was performed before and after surgery for deep venous thrombosis (DVT) confirmation. Patients with new postoperative DVT, typical symptoms of pulmonary embolism (PE), or high Caprini score (≥9) underwent further computer tomography pulmonary angiography (CTPA) examination for PE. Caprini, Rogers, Padua, and Khorana RAM were used for all of the patients. A novel RAM of VTE, which we called Chao-Yang VTE RAM, was developed according to the logistic regression analysis.

Results

The overall incidence of VTE after thoracic surgery was 8.4% (45 of 533). Among the 45 VTE patients, 86.7% have DVT and 13.3% have DVT + PE. Age ≥60 (OR 4.51, 95% CI: 2.09-9.71, P=0.000) has an independent risk factor for VTE. The areas under the receiver operating characteristic (ROC) curve of Caprini, Rogers, Padua, Khorana, and Chao-Yang models were 0.74 (P<0.0001), 0.52 (P=0.62), 0.69 (P<0.0001), 0.64 (P=0.0017), and 0.80 (P<0.0001), respectively. The VTE incidence in the low-, moderate-, and high-risk groups predicted with Chao-Yang scores was 1.3% (3 of 230), 8.4% (14 of 166), and 20.4% (28 of 137); these were 1.6% (3 of 192), 11.9% (38 of 318), and 17.4% (4 of 23), respectively, when using the Caprini criteria. The high-risk group had a significantly higher incidence than the low- and moderate-risk groups (P=0.000). Additionally, as the number of risk factors increased, the incidence of VTE increased from 1.2% to 50.0%.

Conclusions

The incidence of VTE in patients who underwent major thoracic surgery was high in our series. Based on a retrospective single-center population study, we developed a novel prediction model to identify patients receiving thoracic surgery with different risks for VTE events.

Diagnosis of pulmonary embolism: Following the evidence from suspicion to certainty

Accurate, timely and cost-effective identification of pulmonary embolism remains a diagnostic challenge. This article reviews the pulmonary embolism diagnostic process with a focus on the best practice advice from the American College of Physicians. Benefits and risks of each diagnostic step are discussed. Emerging diagnostic tools, not included in the algorithm, are briefly reviewed.

Comparison of Treatment Result Between Anticoagulation Alone and Catheter-Directed Thrombolysis Plus Anticoagulation in Acute Lower Extremity Deep Vein Thrombosis

Purpose

Deep vein thrombosis (DVT) is the third most common cause of cardiovascular morbidity and mortality. Anticoagulation has been the primary treatment modality for acute DVT. However, catheter-directed thrombolysis (CDT) has recently become widely accepted as an additional therapy to anticoagulation. We assessed comparative outcomes in patients with acute DVT who underwent anticoagulation therapy alone (ACA) group and those treated with CDT group.

Materials and Methods

We retrospectively reviewed medical records of 149 patients with DVT from January 2011 to December 2015. We compared patients who received ACA group (n=120) and those who received CDT plus anticoagulation (CDT group, n=29). We analyzed the prevalence of lesions, thrombus removal rate in each lesion, and recurrence-free rate between the two groups.

Results

We found thrombus involvement in a total of 281 lesions in the ACA group and 85 lesions in the CDT group. For the distribution of lesions in each group, those in the femoral vein accounted for 34.2% of all lesions and those in the popliteal vein accounted for 31.7%. During follow-up, the overall thrombus removal rate was 91.1% in the ACA group and 87.0% in the CDT group (P=0.273). The recurrence-free rate was higher in the CDT group in a log-rank test; however, there was no statistically significant difference between the two groups (P=0.594).

Conclusion

According to our results, there was no significant difference in thrombus removal and recurrence-free rates between the CDT and ACA groups. ACA still has an important role in the treatment of DVT.

Activated platelets induce MLKL-driven neutrophil necroptosis and release of neutrophil extracellular traps in venous thrombosis

Venous thromboembolic (VTE) disease, often manifesting as deep vein thrombosis or pulmonary embolism, involves clot formation consisting of blood cells and platelets locked in plasma protein and chromatin networks. The latter derives from neutrophil extracellular traps released by dying neutrophils; however, the molecular mechanisms of neutrophil death in VTE remains unknown. We speculated that mixed lineage kinase-like (MLKL)-driven neutrophil necroptosis contributes to VTE. Indeed, human inferior venous cava thrombus material stained positive for phosphorylated MLKL, the activated version of MLKL that executes necroptotic cell death. In mice, MLKL immunostaining showed co-localization of MLKL with citrullinated histone H3, a marker of neutrophil extracellular trap (NET) formation. These data provide indirect support for a role of MLKL-mediated necroptosis. As a functional proof, both the stabilizer of receptor-interacting protein kinase-1 (RIPK1) and necroptosis inhibitor necrostatin-1s as well as genetic deficiency of MLKL partially prevented clot formation upon inferior vena cava ligation in mice. In both experiments terminal deoxynucleotidyl transferase dUTP nick-end labeling, RIPK3, and citrullinated histone H3+ areas were markedly reduced within the remnant thrombus. In vitro, thrombin-activated platelets induced cell death and NET formation in human neutrophils, which was inhibited by necrostatin-1s treatment. Necrostatin-1s and necrosulfonamide also inhibited neutrophil-platelet aggregate formation induced by tumor necrosis factor-α but had no effect on platelet activation itself. We conclude that in VTE, activated platelets, and possibly other triggers, induce neutrophil necroptosis, a process contributing to clot formation by releasing chromatin in the extracellular space.

Semiautomatic intermittent pneumatic compression device applied to deep vein thrombosis in major orthopedic surgery

Objective

To investigate the effect of additional semiautomatic intermittent pneumatic compression device (IPCD) in the prevention of deep vein thrombosis (DVT) of lower extremity in these patients undergoing major orthopedic surgery, when compared with the conventional graduated compression stockings alone.

Methods

The data of 112 patients undergoing major orthopedic surgery were retrospectively analyzed. 51 patients who ever received IPCD and graduated compression stockings during major orthopedic surgery were taken as the experimental group, and 61 patients who only received the conventional graduated compression stockings during surgery were taken as the observation group. The Doppler sonography was utilized to detect the presence of DVT and pulmonary embolism pre- and postoperatively. Besides, the mean and peak velocity of blood flow in femoral vein were recorded before and after surgery. And then, the comparisons between the two groups were made, respectively.

Results

When compared with the conventional graduated compression stockings alone, the intraoperative application of IPCD and stockings contributed the significant reduction of DVT (3.92%, 2/51 versus 9.84%, 6/61, X² = 5.632, P = 0.034). In terms of the mean and peak velocity of blood flow in femoral vein, the postoperative difference was higher in the observation group than those in the control group (149.56 ± 26.35 versus 130.15 ± 22.56 mm/s, P < 0.05). With respect to perioperative blood loss, the difference between the two groups was statistically significant (800.5 ± 320.7 versus 950.1 ± 305.9 ml, P = 0.031).

Conclusions

Intraoperative application of IPCD could promote blood circulation of lower limbs, and significantly decrease the incidence of potentially fatal DVT in patients undergoing major orthopedic surgery, when compared with the conventional graduated compression stockings.

Combined pharmacotherapy for osteonecrosis of the femoral head after severe acute respiratory syndrome and interstitial pneumonia: two and a half to fourteen year follow-up

PURPOSE

The purpose of this study was to retrospectively analyze the clinical, functional, and radiological outcomes of combined pharmacotherapy to ONFH after high-dose corticosteroid therapy.

METHOD

From August 2003 to June 2015, five patients (ten hips) of ONFH in ARCO stage I, after SARS and Interstitial pneumonia, were treated by combined pharmacotherapy. Lipo-prostaglandin E₁ 10 μg iv Bid × 28 days, enoxaparin 6000 iu H QD × 12 weeks, alendronate sodium tablet 10 mg QD × 1 year. The patients were fully weight-bearing following completion of the follow-up.

RESULT

For these five patients (ten hips), Harris score was 100 from the diagnosis to final follow-up time. Radiologic findings show no signs of collapse, necrotic focus was repaired, and ARCO stages were changed from I_C into II_B.

CONCLUSION

This combined pharmacotherapy has promising treatment results for delaying or preventing collapse of ONFH in ARCO stage I.