Risk for post-thrombotic syndrome after lower-limb deep vein thrombosis: location of the thrombus or residual thrombi?

BACKGROUND

Many works aimed to determine factors that influence the onset of postthrombotic syndrome after an acute episode of deep venous thrombosis. We aimed to compare the prognostic value of the most proximal extent of thrombus (proximal and distal DVT) versus the residual thrombosis as identified by venous ultrasonography performed during follow-up.

METHOD

We conducted a retrospective study of prospectively collected 1183 consecutive cohort patients in the RIETE registry after a first episode of deep venous thrombosis and assessed for postthrombotic syndrome after 12 months.

RESULTS

Multivariate analysis revealed that: residual thrombosis (OR 1.40; 95% CI 0,88-2,21), the presence of cancer (OR 1.38; 95% CI: 0,64-2,97), immobility (OR 1.31; 95% CI 0,70-2,43) and estrogen-containing drugs use (OR 2.08, 95% CI 0,63-6,83), all had a predictive value for the occurrence of PTS.

CONCLUSION

Our study results revealed that ultrasound finding of residual thrombosis is more predictive than proximal location of thrombus for postthrombotic syndrome after episode of deep venous thrombosis. Real life data from a large group of patients from the RIETE registry substantiates that.

Comparative clinical prognosis of massive and non-massive pulmonary embolism: A registry-based cohort study

AIMS

Little is known about the prognosis of patients with massive pulmonary embolism (PE) and its risk of recurrent venous thromboembolism (VTE) compared with non-massive PE, which may inform clinical decisions. Our aim was to compare the risk of recurrent VTE, bleeding, and mortality after massive and non-massive PE during anticoagulation and after its discontinuation.

METHODS AND RESULTS

We included all participants in the RIETE registry who suffered a symptomatic, objectively confirmed segmental or more central PE. Massive PE was defined by a systolic hypotension at clinical presentation (<90 mm Hg). We compared the risks of recurrent VTE, major bleeding, and mortality using time-to-event multivariable competing risk modeling. There were 3.5% of massive PE among 38 996 patients with PE. During the anticoagulation period, massive PE was associated with a greater risk of major bleeding (subhazard ratio [sHR] 1.72, 95% confidence interval [CI] 1.28-2.32), but not of recurrent VTE (sHR 1.15, 95% CI 0.75-1.74) than non-massive PE. An increased risk of mortality was only observed in the first month after PE. After discontinuation of anticoagulation, among 11 579 patients, massive PE and non-massive PE had similar risks of mortality, bleeding, and recurrent VTE (sHR 0.85, 95% CI 0.51-1.40), but with different case fatality of recurrent PE (11.1% versus 2.4%, P = .03) and possibly different risk of recurrent fatal PE (sHR 3.65, 95% CI 0.82-16.24).

CONCLUSION

In this large prospective registry, the baseline hemodynamic status of the incident PE did not influence the risk of recurrent VTE, during and after the anticoagulation periods, but was possibly associated with recurrent PE of greater severity.

D-dimer levels and risk of recurrence following provoked venous thromboembolism: findings from the RIETE registry

BACKGROUND

Patients with venous thromboembolism (VTE) secondary to transient risk factors may develop VTE recurrences after discontinuing anticoagulation. Identifying at-risk patients could help to guide the duration of therapy.

METHODS

We used the RIETE database to assess the prognostic value of d-dimer testing after discontinuing anticoagulation to identify patients at increased risk for recurrences. Transient risk factors were classified as major (postoperative) or minor (pregnancy, oestrogen use, immobilization or recent travel).

RESULTS

In December 2018, 1655 VTE patients with transient risk factors (major 460, minor 1195) underwent d-dimer measurements after discontinuing anticoagulation. Amongst patients with major risk factors, the recurrence rate was 5.74 (95% CI: 3.19-9.57) events per 100 patient-years in those with raised d-dimer levels and 2.68 (95% CI: 1.45-4.56) in those with normal levels. Amongst patients with minor risk factors, the rates were 7.79 (95% CI: 5.71-10.4) and 3.34 (95% CI: 2.39-4.53), respectively. Patients with major risk factors and raised d-dimer levels (n = 171) had a nonsignificantly higher rate of recurrences (hazard ratio [HR]: 2.14; 95% CI: 0.96-4.79) than those with normal levels. Patients with minor risk factors and raised d-dimer levels (n = 382) had a higher rate of recurrences (HR: 2.34; 95% CI: 1.51-3.63) than those with normal levels. On multivariate analysis, raised d-dimers (HR: 1.74; 95% CI: 1.09-2.77) were associated with an increased risk for recurrences in patients with minor risk factors, not in those with major risk factors.

CONCLUSIONS

Patients with raised d-dimer levels after discontinuing anticoagulant therapy for VTE provoked by a minor transient risk factor were at an increased risk for recurrences.

Outcome of Patients with Venous Thromboembolism and Factor V Leiden or Prothrombin 20210 Carrier Mutations During the Course of Anticoagulation

BACKGROUND

Individuals with factor V Leiden or prothrombin G20210A mutations are at a higher risk to develop venous thromboembolism. However, the influence of these polymorphisms on patient outcome during anticoagulant therapy has not been consistently explored.

METHODS

We used the Registro Informatizado de Enfermedad TromboEmbólica database to compare rates of venous thromboembolism recurrence and bleeding events occurring during the anticoagulation course in factor V Leiden carriers, prothrombin mutation carriers, and noncarriers.

RESULTS

Between March 2001 and December 2015, 10,139 patients underwent thrombophilia testing. Of these, 1384 were factor V Leiden carriers, 1115 were prothrombin mutation carriers, and 7640 were noncarriers. During the anticoagulation course, 160 patients developed recurrent deep vein thrombosis and 94 patients developed pulmonary embolism (16 died); 154 patients had major bleeding (10 died), and 291 patients had nonmajor bleeding. On multivariable analysis, factor V Leiden carriers had a similar rate of venous thromboembolism recurrence (adjusted hazard ratio [HR], 1.16; 95% confidence interval [CI], 0.82-1.64), half the rate of major bleeding (adjusted HR, 0.50; 95% CI, 0.25-0.99) and a nonsignificantly lower rate of nonmajor bleeding (adjusted HR, 0.66; 95% CI, 0.43-1.01) than noncarriers. Prothrombin mutation carriers and noncarriers had a comparable rate of venous thromboembolism recurrence (adjusted HR, 1.00; 95% CI, 0.68-1.48), major bleeding (adjusted HR, 0.75; 95% CI, 0.42-1.34), and nonmajor bleeding events (adjusted HR, 1.10; 95% CI, 0.77-1.57).

CONCLUSIONS

During the anticoagulation course, factor V Leiden carriers had a similar risk for venous thromboembolism recurrence and half the risk for major bleeding compared with noncarriers. This finding may contribute to decision-making regarding anticoagulation duration in selected factor V Leiden carriers with venous thromboembolism.

The Clinical Course of Venous Thromboembolism May Differ According to Cancer Site

BACKGROUND

We hypothesized that the clinical course of venous thromboembolism in patients with active cancer may differ according to the specificities of primary tumor site.

AIM AND METHODS

We used data from RIETE (international registry of patients with venous thromboembolism) to compare the clinical venous thromboembolism-related outcomes during the course of anticoagulation in patients with one of the 4 more frequent cancers (breast, prostate, colorectal, or lung cancer).

RESULTS

As of September 2014, 3947 cancer patients were recruited, of whom 938 had breast, 629 prostate, 1189 colorectal, and 1191 lung cancer. Overall, 55% had metastatic disease (42%, 36%, 53%, and 72%, respectively). During the course of anticoagulant therapy (mean duration, 139 days), the rate of thromboembolic recurrences was similar to the rate of major bleeding in patients with breast (5.6 [95% confidence interval (CI), 3.8-8.1] vs 4.1 [95% CI, 2.7-5.9] events per 100 patient-years) or colorectal cancer (10 [95% CI, 7.6-13] vs 12 [95% CI, 9.4-15] per 100 patient-years). In contrast, in patients with prostate cancer, the rate of venous thromboembolic recurrences was half the rate of major bleeding (6.9 [95% CI, 4.4-10] vs 13 [95% CI, 9.2-17] events per 100 patient-years), whereas in those with lung cancer, the rate of thromboembolic recurrences was twofold higher than the rate of major bleeding (27 [95% CI, 22-23] vs 11 [95% CI, 8.6-15] per 100 patient-years).

CONCLUSIONS

Significant differences in the clinical profile of venous thromboembolic-related outcomes were observed according to the site of cancer. These findings suggest the development of cancer-specific anticoagulant strategies as an area for further research.

PO-46 - Influence of extracellular vesicles derived from AML patients on stem cells and their microenvironment

INTRODUCTION

Acute myeloid leukemia (AML) is characterized by rapid growth of leukemic blast cells. Extracellular vesicles (EVs) are shed from normal and pathologic cells and express membrane proteins and antigens, reflecting their cellular origin.

AIM

To explore whether bone marrow EVs of AML patients originate from blast cells and are capable of influencing hematopoietic stem cells (HSC) in a pseudo-natural microenvironment obtained by co-culture of HSC with mesenchymal stem cells (MSC).

MATERIALS AND METHODS

Bone marrow (BM) samples were collected from healthy controls and patients with newly diagnosed AML at three time points: diagnosis, nadir and remission. EV concentration, cell origin and expression of coagulation proteins were characterized by FACS. Stem cells were obtained from Ficoll gradient of cord blood (CB) followed by CD34+ isolation. Cord blood stem cells with or without MSC were co-incubated with AML EVs. EV internalization was demonstrated by FACS-AMNIS and confocal microscopy. Mir-125b and -155 expressions in the cells were analyzed by RT-PCR.

RESULTS

AML patients were enrolled in the study. The total BM-EVs number was higher in patients at first remission compared to controls, while blast EV counts (labeled with anti-CD34, CD33, CD117) were higher in patients at diagnosis compared to controls and to patients in remission. Internalization of CD117+/CD33+ BM-EVs to cord blood stem cells in the presence or absence of MSC was evaluated by FACS-AMNIS. Confocal microscopy of CD33+ stained EVs strengthens the findings and shows presence of EVs even in the cytoplasm and the nucleus. Quantitative analysis of mir-125b and mir-155 expression in cord blood stem cells incubated with AML EVs revealed a clear tendency of increased expression in case of cell exposure to AML EVs in comparison to healthy control EVs. This tendency was emphasized in the presence of MSC.

CONCLUSIONS

EVs of AML patients are generated from blast cells. By internalization into naïve stem cells they can influence their differentiation. Moreover, the presence of mesenchymal stem cells is likely to be essential to the process.

A prognostic score to identify low-risk outpatients with acute deep vein thrombosis in the lower limbs

BACKGROUND

No prior studies have identified which patients with deep vein thrombosis in the lower limbs are at a low risk for adverse events within the first week of therapy.

METHODS

We used data from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) to identify patients at low risk for the composite outcome of pulmonary embolism, major bleeding, or death within the first week. We built a prognostic score and compared it with the decision to treat patients at home.

RESULTS

As of December 2013, 15,280 outpatients with deep vein thrombosis had been enrolled. Overall, 5164 patients (34%) were treated at home. Of these, 12 (0.23%) had pulmonary embolism, 8 (0.15%) bled, and 4 (0.08%) died. On multivariable analysis, chronic heart failure, recent immobility, recent bleeding, cancer, renal insufficiency, and abnormal platelet count independently predicted the risk for the composite outcome. Among 11,430 patients (75%) considered to be at low risk, 15 (0.13%) suffered pulmonary embolism, 22 (0.19%) bled, and 8 (0.07%) died. The C-statistic was 0.61 (95% confidence interval [CI], 0.57-0.65) for the decision to treat patients at home and 0.76 (95% CI, 0.72-0.79) for the score (P = .003). Net reclassification improvement was 41% (P < .001). Integrated discrimination improvement was 0.034 for the score and 0.015 for the clinical decision (P < .001).

CONCLUSIONS

Using 6 easily available variables, we identified outpatients with deep vein thrombosis at low risk for adverse events within the first week. These data may help to safely treat more patients at home. This score, however, should be validated.

Myeloma and thrombotic complications

Multiple myeloma (MM) is a hematological malignancy with high risk for thrombosis. While venous thromboembolism is more common, myeloma patients can also present with arterial thrombosis. Risk factors responsible for this complication can be patient-related, myeloma- and treatment-related. Thromboprophylaxis is indicated along with specific therapeutic regimens employed in myeloma patients. This review will cover potential risk factors for thrombosis in patients with multiple myeloma, prevention recommendations and treatment strategies in this clinical setting.

Silent pulmonary embolism in patients with proximal deep vein thrombosis in the lower limbs

BACKGROUND

One in every three patients with deep vein thrombosis (DVT) in the lower limbs may have silent pulmonary embolism (PE), but its clinical relevance has not been thoroughly studied.

METHODS

We used the RIETE Registry data to study patients with proximal DVT and no PE symptoms, but with a systematic search for PE. We compared the outcome of DVT patients with silent PE and those with no PE.

RESULTS

Of 2375 patients with DVT, 842 (35%) had silent PE and 1533 had no PE. During the first 15 days of anticoagulation, patients presenting with silent PE had a higher incidence of symptomatic PE events than those with no PE (0.95% vs. 0.13%; P = 0.015), with a similar incidence of major bleeding (0.95% vs. 1.63%; P = 0.09). In patients with silent PE, the incidence of PE events during the first 15 days was equal to the incidence of major bleeding (eight events each), but in those with no PE the incidence of PE events was eight times lower (3 vs. 25 bleeding events). Multivariate analysis confirmed that DVT patients with silent PE had a higher incidence of symptomatic PE events during the first 15 days than those with no PE (odds ratio, 4.80; 95% CI, 1.27-18.1), with no differences in bleeding.

CONCLUSIONS

DVT patients with silent PE at baseline had an increased incidence of symptomatic PE events during the first 15 days of anticoagulant therapy. This effect disappeared after 3 months of anticoagulation.