Mechanisms Contributing to Acquired Activated Protein C Resistance in Patients Treated with Thalidomide: A Molecular Dynamics Study.

INTRODUCTION: There is a high incidence of venous thromboembolism (VTE) in patients with Multiple Myeloma (MM), however; until now, the exact mechanisms behind VTE in MM are unknown, and some of the elements that may play a significant role are the treatment with an immunomodulator (IMiD) and acquired resistance to activated protein C (APC). OBJECTIVE: The study aims to reveal the possible mechanisms linked to the reduced antithrombotic activity of APC associated with thalidomide. METHODS: The molecular docking approach was used to ascertain the in silico inhibitory potential of thalidomide on the APC protease domain in the architecture of the catalytic triad and its interaction with major substrate binding sites. RESULTS: The coupling showed that the inhibitory activity of thalidomide depends on the induction of structural changes in the protease domain of APC, at the level of the Ser/His/Asp catalytic triad, as a result of a significant increase between the distances of CαAsp102 and Cα Ser195 (11.175 angstroms, increase 14.83%) and between CαSer195 and CαHis57 (9.478 angstroms, increase 13.78 %). This can result in an inefficient transfer of the proton between these residues, the other possible mechanism of inhibition, is a potential reduced binding of the substrate as a result of a direct interaction through a carbon-hydrogen bond on His57, an H-bond on Arg306, and a carbon hydrogen bond on Arg506. CONCLUSION: We demonstrate the in silico inhibitory potential of thalidomide on APC, through two possible inhibition mechanisms, a pathophysiologically relevant finding to understand the factors that can affect the stability and functions of APC in vivo.

Activated protein C resistance impact on Syrian candidates for in vitro fertilisation and the benefit of anticoagulation therapy: a retrospective cohort study.

Activated protein C resistance (APCR) is a common thrombophilia, caused mainly by a mutation. The impact of APCR on the efficacy of In Vitro Fertilization (IVF) are still unclear, and no solid recommendations for its management were published. To investigate the effect of APCR on IVF outcomes and assess the efficacy of our management protocol, we retrospectively scanned the medical records of women who were tested with APCR assay in 2019 at our fertility centre. The 66 women (12%) positive for APCR had lower odds of reaching clinical pregnancies after IVF 0.18 [95% CI: 0.07-0.47] and fewer live births. The administration of low-molecular-weight heparin and aspirin associated with more implantation in treated compared to untreated APCR-positive women with an odds ratio of 43.2 [7.51-248.6]. In conclusion, APCR negatively affects the number of clinical pregnancies after IVF, but anticoagulation therapy can mitigate this effect and significantly increase clinical pregnancies.Impact StatementWhat is already known on this subject? The evidence about the impact of APCR on IVF outcomes is still inconclusive. According to the Canadian guideline, routine screening for thrombophilia in patients with recurrent pregnancy loss is not recommended. No clear recommendations regarding the management of APCR in the planning for IVF are yet available.What do the results of this study add? APCR significantly increases implantation failure among infertile women who conduct IVF. Management of APCR using LMWH and aspirin was effective in mitigating this effect and increasing successful implantation.What are the implications of these findings for clinical practice and/or further research? Our findings can support the recommendation to include APCR assay in the routine tests for infertile women conducting IVF, and suggest the combination between LMWH and aspirin as an effective therapy to increase successful implantation in APCR positive candidates. However, more controlled clinical trials are still needed to confirm our results.

The impact of activated protein C resistance on the patency of arteriovenous grafts for hemodialysis access.

INTRODUCTION: Vascular access is required for hemodialysis treatment. An effect of activated protein C resistance on access thrombosis rates has not yet been investigated. The aim of this study is to determine whether an activated protein C resistance is correlated with the patency of polytetrafluoroethylene arteriovenous grafts. METHODS: The primary endpoint was the impact of activated protein C resistance; secondary endpoints were the influence of Factor V Leiden thrombophilia, homocysteine, ß2-glycoprotein antibodies, and other laboratory values on the assisted primary patency. RESULTS: Forty-three grafts in 43 patients were included. The overall mean assisted primary patency was 18.4 months (±3.16 SE). Activated protein C resistance (p = 0.01) and ß2-glycoprotein antibodies (p = 0.018) had a significant influence on the assisted primary patency. The assisted primary patency for patients with low (<4) activated protein C resistance was 9.3 months compared to 24.8 of those with a high (≥4) activated protein C resistance. Patients with low (≤2.6) ß2-glycoprotein antibodies presented an assisted primary patency of 31.8 months whereas those with high (>2.6) ß2-glycoprotein antibodies showed 9.3 months. In all patients with a pathologic activated protein C resistance, a heterozygous or homozygous Factor V Leiden thrombophilia was detected. CONCLUSIONS: This study identified low activated protein C resistance and high ß2-glycoprotein antibodies as risk factors for thrombosis in polytetrafluoroethylene arteriovenous grafts. A prospective study is needed to clarify if oral anticoagulation should be administered to all patients with a pathologic activated protein C resistance blood value and/or factor V Leiden mutation.

Main Factors Predicting Nonresponders to Autologous Cell Therapy for Critical Limb Ischemia in Patients With Diabetic Foot.

Autologous cell therapy (ACT) is a new treatment for patients with no-option critical limb ischemia (NO-CLI). We evaluated the factors involved in the nonresponse to ACT in patients with CLI and diabetic foot. Diabetic patients (n = 72) with NO-CLI treated using ACT in our foot clinic over a period of 8 years were divided into responders (n = 57) and nonresponders (n = 15). Nonresponder was defined as an insufficient increase in transcutaneous oxygen pressure by <5 mm Hg, 3 months after ACT. Patient demographics, diabetes duration and treatment, and comorbidities as well as a cellular response to ACT, limb-related factors, and the presence of inherited thrombotic disorders were compared between the 2 groups. The main independent predictors for an impaired response to ACT were heterozygote Leiden mutation (OR 10.5; 95% CI, 1.72-4) and homozygote methylenetetrahydrofolate reductase (MTHFR 677) mutation (OR 3.36; 95% CI, 1.0-14.3) in stepwise logistic regression. Univariate analysis showed that lower mean protein C levels (P = .041) were present in nonresponders compared with responders. In conclusion, the significant predictors of an impaired response to ACT in diabetic patients with NO-CLI were inherited thrombotic disorders.

Anti-protein C antibodies and acquired protein C resistance in SLE: novel markers for thromboembolic events and disease activity?

OBJECTIVES: Risk factors for thromboembolism in SLE are poorly understood. We hypothesized a possible role for protein C, based on its dual activity in inflammation and haemostasis and on the evidence of an association between acquired activated protein C (APC) resistance (APCR) and high-avidity anti-protein C antibodies (anti-PC) with a severe thrombotic phenotype in venous thrombosis APS patients. METHODS: In a cross-sectional study of 156 SLE patients, the presence and avidity of IgG anti-PC was established by in house-ELISA, and APCR to exogenous recombinant human APC (rhAPC) and Protac (which activates endogenous protein C) was assessed by thrombin generation-based assays. Associations with aPL profile, thrombotic history and disease activity (BILAG and SLEDAI-2K) were also established. RESULTS: Anti-PC were detected in 54.5% of patients and APCR in 59%. Anti-PC positivity was associated with APCR to both rhAPC (P <0.0001) and Protac (P =0.0001). High-avidity anti-PC, detected in 26.3% of SLE patients, were associated with APCR in patients with thrombosis only (P <0.05), and with the development of thrombosis over time (range: 0-52 years; P =0.014). High-avidity anti-PC levels correlated with SLEDAI-2K (P =0.033) and total BILAG (P =0.019); SLEDAI-2K correlated inversely with APCR to Protac (P =0.004). CONCLUSION: Anti-PC occur in patients with SLE, independently of aPL profile, and are associated with APCR. High-avidity anti-PC are associated with thrombosis and with active disease and might prove a novel marker to monitor the risk of thrombosis and disease progression in SLE.

Pulmonary embolism in Behcet's disease: a case report.

Behcet's disease (BD) is a vasculitis of unknown etiology. It is often correlated with thrombophilic factors such as V Leiden. Pulmonary involvement is reported in 1-10% of patients. The most common manifestations are pulmonary aneurysms while pulmonary embolism is a rare complication. A 41-year old man with BD and V Leiden heterozygosity complained of pleurodynia and fever. Pleurodynia deteriorated in the following days and PE was confirmed by CT angiography, without the presence of aneurysms. After the exclusion of the antiphospholipid syndrome, a therapeutic dose of apixaban was initiated. Two weeks later, pleurodynia relapsed in combination with pleural effusion unilaterally. These findings were attributed to disease exacerbation. For this reason, we decided to enhance the immunosuppressive therapy. Six months later, CTPA showed complete remission of the clots. Vasculitis predisposes to thrombosis with or without coexisting thrombophilia. Clinicians should include them in their differential diagnosis and provide personalized treatment, based on immunosuppressants.

Anti-Domain I ß2-Glycoprotein I Antibodies and Activated Protein C Resistance Predict Thrombosis in Antiphospholipid Syndrome: TAC(I)T Study.

BACKGROUND: Antibodies binding to domain I of ß2-glycoprotein I (aDI) and activated protein C (APC) resistance are associated with an increased risk of thrombosis in cross-sectional studies. The objective of this study was to assess their predictive value for future thromboembolic events in patients with antiphospholipid antibodies (aPL) or antiphospholipid syndrome. METHODS: This prospective multicenter cohort study included consecutive patients with aPL or systemic lupus erythematosus. We followed 137 patients (43.5 ± 15.4 year old; 107 women) for a mean duration of 43.1 ± 20.7 months. RESULTS: We detected aDI IgG antibodies by ELISA in 21 patients. An APC sensitivity ratio (APCsr) was determined using a thrombin generation-based test. The APCsr was higher in patients with anti-domain I antibodies demonstrating APC resistance (0.75 ± 0.13 vs 0.48 ± 0.20, P < 0.0001). In univariate analysis, the hazard ratio (HR) for thrombosis over time was higher in patients with aDI IgG (3.31 [95% CI, 1.15-9.52]; P = 0.03) and patients with higher APC resistance (APCsr >95th percentile; HR, 6.07 [95% CI, 1.69-21.87]; P = 0.006). A sensitivity analysis showed an increased risk of higher aDI IgG levels up to HR 5.61 (95% CI, 1.93-16.31; P = 0.01). In multivariate analysis, aDI IgG (HR, 3.90 [95% CI, 1.33-11.46]; P = 0.01) and APC resistance (HR, 4.98 [95% CI, 1.36-18.28]; P = 0.02) remained significant predictors of thrombosis over time. CONCLUSIONS: Our study shows that novel tests for antibodies recognizing domain I of ß2-glycoprotein I and functional tests identifying APC resistance are significant predictors of thrombosis over time and may be useful for risk stratification.

Inherited Thrombophilia in a Lebanese Family of Four Generations: A Case Report of Recurrent Miscarriage.

INTRODUCTION: Factor V Leiden (G1691A), prothrombin (G20210A) and MTHFR (C677T) gene mutations were investigated in many studies for their association with Deep Venous Thrombosis. CASE PRESENTATION: A North Lebanese family has been examined, from an index case, a 40-year-old woman, who had a history of venous thrombosis with unexplained recurrent miscarriage. The index case was found to be heterozygous for factor V Leiden G1691A, prothrombin G20210A, and methylenetetrahydrofolate reductase C677T gene variants. Her family members were heterozygous for at least two of the three-point mutations, and multiple risk factors associated with thrombophilia were identified. CONCLUSION: Our findings emphasize the need for clarifying the utility and futility of thrombophilia testing in the era of molecular diagnostics.

[Retinal artery occlusion and anterior ischemic optic neuropathy associated with factor V Leiden mutation: A case report]. / Occlusion de l'artère centrale de la rétine associée à une neuropathie optique ischémique antérieure secondaire à une mutation du facteur V Leiden : à propos d'un cas.

Factor V is a pro-coagulant cofactor required for the transformation of prothrombin into thrombin. Thrombin activates factor V, which is then deactivated by protein C. A mutation in factor V is responsible for the formation of factor V Leiden, resistant to activated protein C. The association of this mutation with venous thromboses has been established. Its association with arterial occlusions is still controversial. We report the case of a central retinal artery occlusion associated with a non-arteritic anterior optic neuropathy associated with a Leiden mutation of factor V (FVL). The presence of FVL has been associated with lack of reperfusion and rapid progression to neovascularization. It seems that FVL intervenes mainly during the reperfusion phase after the occurrence of arterial thrombosis.

Factor V Leiden thrombophilia dental considerations.

Factor V Leiden thrombophilia, a relatively common inherited type of hypercoagulability resulting from a mutation in the gene for factor V, has received minimal attention in the dental literature. This review examines related demographic information, risk factors, comorbidities, the thrombotic mechanism, clinical features, diagnostic measures, and medical management strategies. In addition, oral and maxillofacial sequelae and management guidelines are provided. If a patient is known to have the mutation, the clinician should review the patient's potential risk factors for development of thrombosis and ascertain whether any coagulation agents are currently being administered. The practitioner should be prepared to manage instances of prolonged bleeding. The dentist also should be aware of an overall increased risk of systemic thromboembolic events, particularly following head and neck trauma. Rarely, the factor V Leiden mutation has been associated with osteonecrosis of the jaw, usually concurrent with intake of sex hormones.

[Thrombophilia in systemic lupus erythematosus: A case-control study]. / Les marqueurs de thrombophilie au cours du lupus érythémateux systémique : une étude cas-témoin.

INTRODUCTION: To investigate the thrombotic tendency in patients with systemic lupus erythematosus (SLE) by evaluating congenital and acquired abnormalities with an increased risk of thrombosis. PATIENTS AND METHODS: A total of 53 patients with SLE were included in the study. Fifty-three healthy controls paired by age and sex were assessed. Anticardiolipin antibodies (aCL), anti ß2 glycoprotein (aß2GP), lupus anticoagulant (LAC), protein C (PC), protein S (PS), antithrombin (AT), acquired activated protein C, and homocysteinemia were evaluated. Comparisons for categorical variables were analyzed by Chi2 and student tests. RESULTS: The patients were all female and had a mean age of 30.6 years (16/58). The healthy controls were all female and their mean age was 30.8 years (17/56). Five patients (9.4%) developed venous thrombosis during the 24 months of follow-up. The antiphospholipid antibodies were positive in 17 patients (32.1%) and negative in all healthy controls (P=0.01). PS deficiency was noted in 17 patients (32.1%) and in 5 controls (P=0.004). Hyperhomocysteinemia was noted in 16 patients (30.2%) versus 3 controls (5.6%) (P=0.002). Test for PC deficiency and acquired activated protein C showed no significant difference between the two groups. No AT deficiency was found in the patients. The study of clinical and biological correlations based on the presence and absence of thrombophilic parameters concluded to a significant association between Protein C deficit and thrombosis (P=0.02) and acquired activated protein C resistance and thrombosis (P=0.04). There was no significant association between the APL and thrombosis. CONCLUSION: Thrombophilic abnormalities were significantly more frequent in lupus patients than in healthy controls. Thrombotic events were significantly associated with PC deficit and acquired protein C resistance. There was no correlation between antiphospholipid antibodies and thrombosis.

Recurrent thrombosis after carotid endarterectomy secondary to activated protein C resistance and essential thrombocytosis: A case report.

RATIONALE: Thrombosis is a major cause of morbidity in the perioperative period. Although many risk factors are known, activated protein C resistance is a prominent risk for thrombosis. Activated protein C resistance frequently occurs with recurrent thromboembolism. PATIENT CONCERNS: A 59-year-old Korean woman patient with hypertension was admitted due to dysarthria and left side motor weakness. DIAGNOSIS AND INTERVENTIONS: Magnetic resonance imaging showed subacute cerebral infarction with right frontoparietal lobe and stenosis at the right internal carotid artery. She underwent right carotid endarterectomy under general anesthesia. However, recurrent thrombosis on postoperative day 1 was noted at patient's right carotid artery, which prompted emergency surgery. Additional preoperative laboratory review revealed findings for activated protein C resistance, low protein S activity, antinuclear antibody (>1:160), anti-cardiolipin IgM antibody (16.6), and thrombocytosis, Janus kinase and factor V Leiden mutations. At the intensive care unit, heparin was continually infused until postoperative day 12 and was then switched to warfarin. OUTCOMES: Patient was discharged at postoperative day 21 without any event. Patient had no signs of recurrence within the 3-year follow-up period, and she is still on oral warfarin and clopidogrel. LESSONS: Screening test for hypercoagulability can be used to identify patients at higher risk of postoperative complications. If hypercoagulability state is confirmed by laboratory testing, a suitable anticoagulant treatment plan should be made within the perioperative period.

[Pulmonary Embolism Despite Rivaroxaban in an Obese Patient]. / Pulmonalembolie trotz Rivaroxaban bei einer adipösen Patientin.

Introduction Rivaroxaban, an oral factor Xa inhibitor, is approved for therapy of venous thromboembolism. It is unclear whether the standard dose for patients with a body mass index (BMI) > 40 kg/m2 is sufficient. History The 45-year-old patient was admitted because of increasing respiratory distress. She had a history of pulmonary embolism 30 months before the admission, a factor V Leiden mutation and several hospitalisations due to dermatomycoses. The patient briefly took phenprocoumon which was changed to 20 mg rivaroxaban due to a lack of adherence. Six months before admission, the patient paused the rivaroxaban therapy because of dental surgery and suffered a recurrent pulmonary embolism. Findings and Diagnosis The patient presented with increasing difficulty of breathing, morbid obesity with a BMI of 59.3 kg/m2 and intertrigo of the lower extremities. The ECG showed a right axis deviation, a pulmonary P-wave and an incomplete right bundle branch block. Computed tomography showed pulmonary embolisms of the left lower lobe. The pulmonary artery was dilated, and the right atrium was enlarged. Venous thrombosis of the lower limb could not be certainly ruled out. The D-dimer was elevated with 5.895 mg/L (normal value up to 169 mg/L) and NT-pro-BNP was elevated at 5.580 ng/L (normal value up to 0.5 ng/L). Sixteen hours after the onset of symptoms, 22 hours after the last dose, the serum rivaroxaban level was 137 ng/ml. According to manufacturers, the therapeutic range of rivaroxaban after 2 - 4 hours is 22 - 535 ng/ml, and after 24 hours 6 - 239 ng/ml. Therapy and course After initiation of a therapy with low-molecular weight heparin and subsequent oral anticoagulation with phenprocoumon, the symptoms decreased. Conclusions It is highly probable that the pulmonary embolism occurred at a time when the rivaroxaban level was in the therapeutic range. Since there are only few data about safety and efficacy of rivaroxaban and other non-vitamin K-oral anticoagulants (NOACs) in severely obese patients, the recommendations of the "International Society for Thrombosis and Haemostasis" should be followed: Rivaroxaban and other NOACs should not be used in patients with a BMI > 40 kg/m2 or weight > 120 kg, since only few data on this patient group are available. If NOACs are necessary in these patients, serum concentrations of NOACs should be measured.

An extensive suprarenal inferior vena cava thrombosis successfully treated with catheter-directed thrombolysis in a postpartum 14-year-old girl.

We report a case of extensive early postpartum acute suprarenal inferior vena cava thrombosis in a 14-year-old girl. Management included catheter-directed-thrombolysis, aiming to save renal function and prevent fatal pulmonary embolism. Treatment decisions were mostly based on adult guidelines, as guidelines for the paediatric population are not yet available.

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.

Bilateral Legg-Calve-Perthes Disease and Kienbock's Disease in a Child With Factor V Leiden Thrombophilia: A Case Report.

Background: The etiology of multifocal osteonecrosis is not definitively known; however, hypercoagulable state is a very plausible cause. Methods: We present an unusual case of a 12-year-old boy with a history of Legg-Calve-Perthes disease presenting with right wrist pain who was subsequently diagnosed with Kienbock's disease. The finding of multifocal osteonecrosis prompted testing for a hypercoagulable state that was positive for Factor V Leiden thrombophilia. A thorough literature review using Medline database was conducted to investigate associations between inherited hypercoagulable states and multifocal osteonecrosis. Results: Our literature review identified 2 similar cases of multifocal osteonecrosis associated with a hypercoagulable disorder in adult patients. There were no reports among the pediatric patient population. Meta-analysis has demonstrated a potential link between Legg-Calve-Perthes disease and Factor V Leiden thrombophilia. Conclusions: This study offers further evidence to support the theory that multifocal osteonecrosis may be linked to a hypercoagulable state. Patients presenting with multifocal osteonecrosis should undergo screening for hypercoagulable states. Further investigation is needed to ascertain the potential benefit of prophylactic anticoagulation in patients with a known hypercoagulable state and multifocal osteonecrosis.

Activated Protein C Resistance Does Not Increase Risk for Recurrent Stroke or Death in Stroke Patients.

BACKGROUND: Activated protein C (APC) resistance is the most common inherited prothrombotic disorder. The role of APC resistance in ischemic stroke is controversially discussed. OBJECTIVES: The aim of this single center follow up study was to investigate the effect of APC resistance on stroke recurrence and survival in stroke patients. PATIENTS/METHODS: We retrospectively identified 966 patients who had had an ischemic stroke or transitory ischemic attack (TIA) and in whom laboratory tests for APC resistance had been conducted. These patients were contacted to determine the primary outcomes of recurrent ischemic stroke or death. RESULTS: A total of 858 patients with an average follow up time of 8.48 years were included. APC resistance did not influence cumulative incidence functions for stroke free and total survival. In multivariate analyses, crude and adjusted hazard ratios for recurrent stroke as well as for death where not significantly increased in patients with APC resistance. This also applies to the subgroups of young patients, patients with cryptogenic stroke and patients with atrial fibrillation. CONCLUSION: APC-resistance is not a risk factor for subsequent stroke or death in patients with a first ischemic stroke or TIA. Testing for APC-resistance in stroke patients therefore cannot be routinely recommended.