Desmopressin as a Treatment in Patients With Von Willebrand Disease: A Systematic Review

Von Willebrand disease (VWD) and hemophilia A are the most common inherited bleeding disorders. Quantitative or qualitative von Willebrand factor (VWF) anomalies cause this disorder in men and women. VWF, a plasma glycoprotein, relies on platelets for primary hemostasis. It also carries and stabilizes factor VIII in the blood. VWD has several categories. Types 1 and 3 have partial or total VWF quantitative deficiencies. However, type 2 and its subtypes have VWF quality issues. The major treatment is desmopressin (DDAVP), which replaces endogenous VWF and factor VIII (FVIII). Plasma-derived VWF/FVIII products may also be substituted exogenously. Treatment with plasma-derived or recombinant VWF concentrates without FVIII is also possible. The purpose of this retrospective, single-center research was to evaluate DDAVP's efficacy in treating VWD based on many criteria established in the current literature. We looked at the results on Google Scholar, the Cochrane Library, and PubMed/Medline. There were a total of 10 papers found, evaluated, and accepted for inclusion in this study. A comprehensive analysis of DDVAP's role in VWD was compiled from the aforementioned papers. Various aspects of DDVAP were captured by including an analysis of complementary treatments used in surgical and clinical settings. We also describe the treatment's intended impact on the different variations of the disease. Given these results, further investigation is required to determine the most effective method for managing VWD so that it may be included in standard clinical practice.

Levels of procoagulant microparticles expressing phosphatidylserine contribute to bleeding phenotype in patients with inherited thrombocytopenia

Inherited thrombocytopenia is a heterogeneous group of hereditary disorders with varying bleeding tendencies, not simply related to platelet count. Platelets transform into different subpopulations upon stimulation, including procoagulant platelets and platelet microparticles (PMPs), which are considered critical for haemostasis. We aimed to investigate whether abnormalities in PMP and procoagulant platelet function were associated with the bleeding phenotype of inherited thrombocytopenia patients. We enrolled 53 inherited thrombocytopenia patients. High-throughput sequencing of 36 inherited thrombocytopenia related genes was performed in all patients and enabled a molecular diagnosis in 57%. Bleeding phenotype was evaluated using the ISTH bleeding assessment tool, dividing patients into bleeding (n = 27) vs. nonbleeding (n = 26). Unstimulated and ADP, TRAP or collagen-stimulated PMP and procoagulant platelet functions were analysed by flow cytometry using antibodies against granulophysin (CD63), P-selectin (CD62P), activated GPIIb/IIIa (PAC-1) and a marker for phosphatidylserine expression (lactadherin). Procoagulant platelets were measured in response to collagen stimulation. An in-house healthy reference level was available. Overall, higher levels of activated platelets, PMPs and procoagulant platelets were found in nonbleeding patients compared with the reference level. Nonbleeding patients had higher proportions of phosphatidylserine and PMPs compared with bleeding patients and the reference level, in response to different stimulations. Interestingly, this finding of high proportions of phosphatidylserine and PMPs was limited to PMPs, and not present in procoagulant platelets or platelets. Our findings indicate that nonbleeding inherited thrombocytopenia patients have compensatory mechanisms for improved platelet subpopulation activation and function, and that generation of phosphatidylserine expressing PMPs could be a factor determining bleeding phenotype in inherited thrombocytopenia.

Effect of DDAVP on Platelet Activation and Platelet-Derived Microparticle Generation

BACKGROUND

 The way by which 1-deamino-8-D-arginine vasopressin (DDAVP) acts on platelets remains unclear. Data from the literature tend to show that there is no definite effect on platelet activation, but recent work has suggested that a subtype of platelets, activated by the combined action of collagen and thrombin, was triggered by DDAVP. Moreover, platelet microparticles (PMPs), which have been shown to be procoagulant, have rarely been studied in this context. The goal of this study was to analyze the effects of DDAVP on PMPs' release through platelet activation.

METHODS

 Fifteen out of 18 consecutive patients undergoing a therapeutic test with DDAVP were included. They were suffering from factor VIII deficiency or from von Willebrand disease. The expression of P-selectin and PAC-1 binding on platelets and the numbers of circulating PMPs were evaluated ex vivo before and after DDAVP infusion. Peripheral blood was collected on CTAD to limit artifactual platelet activation.

RESULTS

 DDAVP induced a significant decrease of platelet counts and volume. Only small changes of P-selectin expression and PAC-1 binding were observed. Considering PMPs, two populations of patients could be defined, respectively, with (120%, n = 6) or without (21%, n = 7) an increase of PMPs after DDAVP. The decrease in platelet counts and volume remained significant in the group of responders.

CONCLUSION

 This study shows that DDAVP induces the generation/release of PMPs in some patients with factor VIII deficiency and von Willebrand disease 1 hour after DDAVP infusion.

Microparticle analysis in disorders of hemostasis and thrombosis

Microparticles (MPs) are submicron vesicles released from the plasma membrane of eukaryotic cells in response to activation or apoptosis. MPs are known to be involved in numerous biologic processes, including inflammation, the immune response, cancer metastasis, and angiogenesis. Their earliest recognized and most widely accepted role, however, is the ability to promote and support the process of blood coagulation. Consequently, there is ongoing interest in studying MPs in disorders of hemostasis and thrombosis. Both phosphatidylserine (PS) exposure and the presence of tissue factor (TF) in the MP membrane may account for their procoagulant properties, and elevated numbers of MPs in plasma have been reported in numerous prothrombotic conditions. To date, however, there are few data on true causality linking MPs to the genesis of thrombosis. A variety of methodologies have been employed to characterize and quantify MPs, although detection is challenging due to their submicron size. Flow cytometry (FCM) remains the most frequently utilized strategy for MP detection; however, it is associated with significant technological limitations. Additionally, preanalytical and analytical variables can influence the detection of MPs by FCM, rendering data interpretation difficult. Lack of methodologic standardization in MP analysis by FCM confounds the issue further, although efforts are currently underway to address this limitation. Moving forward, it will be important to address these technical challenges as a scientific community if we are to better understand the role that MPs play in disorders of hemostasis and thrombosis.

Selective serotonin reuptake inhibitor use during pregnancy increases the risk of postpartum hemorrhage and anemia: a hospital-based cohort study

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) are known to increase the risk of gastrointestinal bleeding.

OBJECTIVE

Study the risk of bleeding-related complications in relation to SSRI in pregnancy.

PATIENTS/METHODS

This was a hospital-based cohort study. All women who gave birth at Karolinska University Hospital in Stockholm over a 5-year period (2007 to 2011) were included in the study. Those women who the electronic maternal health record indicated were using SSRI (n = 500) were considered exposed, and all other women formed a control population (n = 39,594). The main outcome measures were blood loss, postpartum hemorrhage (PPH), PP anemia and length of hospitalization.

RESULTS

The absolute risk of PPH and PP anemia for the 1.2% exposed to SSRI were 18.0% and 12.8%, respectively. Women with a vaginal non-surgical delivery who reported use of SSRI during pregnancy had approximately a 2-fold increased risk of both PPH (OR, 2.6; 95% CI, 2.0-3.5) and PP anemia (OR, 2.1; 95% CI, 1.5-2.9), as compared with controls. Blood loss and length of hospitalization were significantly higher among women using SSRI than non-users (arithmetic mean 484 mL vs. 398 mL, 3.8 days vs. 2.4 days, respectively).

CONCLUSION

The use of SSRI during pregnancy increases blood loss and doubles the risk of PPH and PP anemia in a setting where SSRI had not been considered a risk factor for increased blood loss. Because PPH is a leading cause of maternal mortality and morbidity, the awareness of bleeding-related complications is important, both in relation to pregnancy and to surgery in general.

Hemolytic anemia and metastatic carcinoma: case report and literature review

Hemolytic anemia can complicate the development of a variety of solid tumors and hematologic malignancies. Although patients may have an established diagnosis with documented metastases, microangiopathic hemolytic anemia (MAHA) can be a presenting feature of an occult malignancy. Prompt diagnosis is essential because conditions that mimic the symptoms of MAHA, including thrombotic thrombocytopenic purpura, have different prognoses and therapeutic options. Although the exact pathogenesis is not yet delineated, we present herein a case of cancer-associated MAHA and discuss the known pathways that can contribute to the initiation and propagation of hemolytic anemia in patients with cancer. The patient is a 69-year-old woman with breast carcinoma that had metastasized to her rectum, urinary bladder, and brain. She eventually developed progressive decline in her functional status, with intermittent epistaxis and melena. The results of laboratory studies revealed hemolytic anemia and thrombocytopenia; results of a bone-marrow biopsy confirmed the involvement by metastatic carcinoma. The patient received red blood cell and platelet transfusions and was discharged to hospice care after clinical stabilization. She died soon thereafter.

Addition of in-vitro generated endothelial microparticles to von-Willebrand plasma improves primary and secondary hemostasis

Increased endothelial microparticles (EMP) as markers for endothelial activation have been associated with worse outcomes in clinical prothrombotic situations. The procoagulant properties of EMP can be attributed to the expression of phospholipids, tissue factor and von-Willebrand factor on their surface. We therefore investigated whether addition of in-vitro generated EMP modifies hemostasis in plasma from patients with severe von-Willebrand disease (VWD). A large EMP pool was obtained from stimulated endothelial cell lines and EMP concentration was quantified by flow cytometry. The influence of EMP on primary and secondary hemostasis in VWD plasma was assessed using ristocetin-induced platelet aggregation (RIPA) and thrombin generation in a calibrated automated thrombogram (CAT), respectively. After addition of EMP, there was a significant increase in the maximal aggregation level in RIPA as well as a significant shortening of lag time and time-to-peak in CAT in comparison to control buffer. In summary, in vitro-generated EMP have the potential to improve hemostasis in severe VWD plasma and these results warrant further clinical reseach regarding their contribution to the clinical bleeding phenotype as well as their potential to improve replacement therapy.