Cancer and thrombosis: Managing the risks and approaches to thromboprophylaxis

Patients with cancer are at increased risk of venous thromboembolism (VTE) compared with patients without cancer. This results from both the prothrombotic effects of the cancer itself and iatrogenic factors, such as chemotherapy, radiotherapy, indwelling central venous devices and surgery, that further increase the risk of VTE. Although cancer-associated thrombosis remains an important cause of morbidity and mortality, it is often underdiagnosed and undertreated. However, evidence is accumulating to support the use of low-molecular-weight heparins (LMWHs) in the secondary prevention of VTE in patients with cancer. Not only have LMWHs been shown to be at least as effective as coumarin derivatives in this setting, but they have a lower incidence of complications, including bleeding, and are not associated with the practical problems of warfarin therapy. Furthermore, a growing number of studies indicate that LMWHs may improve survival among patients with cancer due to a possible antitumor effect. Current evidence suggests that LMWHs should increasingly be considered for the long-term management of VTE in patients with cancer

Dental management considerations for the patient with an acquired coagulopathy. Part 1: Coagulopathies from systemic disease

Current teaching suggests that many patients are at risk for prolonged bleeding during and following invasive dental procedures, due to an acquired coagulopathy from systemic disease and/or from medications. However, treatment standards for these patients often are the result of long-standing dogma with little or no scientific basis. The medical history is critical for the identification of patients potentially at risk for prolonged bleeding from dental treatment. Some time-honoured laboratory tests have little or no use in community dental practice. Loss of functioning hepatic, renal, or bone marrow tissue predisposes to acquired coagulopathies through different mechanisms, but the relationship to oral haemostasis is poorly understood. Given the lack of established, science-based standards, proper dental management requires an understanding of certain principles of pathophysiology for these medical conditions and a few standard laboratory tests. Making changes in anticoagulant drug regimens are often unwarranted and/or expensive, and can put patients at far greater risk for morbidity and mortality than the unlikely outcome of postoperative bleeding. It should be recognised that prolonged bleeding is a rare event following invasive dental procedures, and therefore the vast majority of patients with suspected acquired coagulopathies are best managed in the community practice setting

The incidence of venous thromboembolism in family members of patients with factor V Leiden mutation and venous thrombosis

Background: The factor V Leiden mutation is a genetic defect associated with an increased incidence of Venous thromboembolism. When the incidence of venous thromboembolism in relatives of patients known to have the mutation outweighs the disadvantages of prophylactic strategies, family screening may be necessary. Objective: To determine the incidence of venous thromboembolism in first-degree relatives of symptomatic carriers of the factor V Leiden mutation. Design: Retrospective blinded study. Setting: University hospitals. Participants: 437 first-degree relatives of 112 heterozygous propositi and 30 relatives of 6 homozygous propositi. Measurements: Before DNA testing, information on previous venous thromboembolism and concomitant risk factors was obtained. Relatives with and without the FV: Q(506) mutation were compared. Results: The annual incidence of thromboembolism in relatives of heterozygous propositi was 0.45% (95% CI, 0.28% to 0.61%) in those with the mutation and 0.10% (CI, 0.02% to 0.19%) in those without the mutation (relative risk, 4.2 [CI, 1.8 to 9.9]). Among carriers, the incidence increased from 0.25% (CI, 0.12% to 0.49%) in the 15- to 30-year-old age group to 1.1% (CI, 0.24% to 3.33%) in persons older than 60 years of age. Half of the episodes of Venous thromboembolism occurred spontaneously, 20% were related to surgery, and 30% were associated with pregnancy or use of oral contraceptives. Conclusions: The observed low annual risk for venous thromboembolism in persons carrying the factor V Leiden mutation does not seem to outweigh the risks for bleeding associated with coumarin prophylaxis or justify discouragement of the use of oral contraceptives. A general policy of screening the families of all patients with the factor V Leiden mutation does not seem to be indicated. The observations in this moderate-size, retrospective study need to be confirmed by prospective follow-up studies

The incidence of recurrent venous thromboembolism in carriers of factor V Leiden is related to concomitant thrombophilic disorders

The duration of anticoagulant treatment after a first episode of venous thromboembolism primarily depends on the risk of recurrence, Variability of recurrence rates in factor (F) V Leiden carriers may be due to concomitant thrombophilic disorders. A retrospective study was performed in 329 FV Leiden carriers with a history of venous thromboembolism (262 probands, 67 relatives). The annual rate of first recurrence was estimated in relatives. The contribution of concomitant thrombophilic disorders to the recurrence rate was evaluated in probands and relatives by a nested case-control analysis in 10 5 matched pairs of carriers either with or without recurrence, The overall annual recurrence rate was 2.3 per 100 patient-years, The adjusted risk of recurrence for concomitant thrombophilic disorders was: 9.1 (1.3-62.8) for the FII mutation; 1.0 (0.2-4.9) for homozygosity for FV Leiden; 1.5 (0.2-9.5) for inherited deficiencies of protein C or S: 1.8 (0.7-4.9) for FVIII coagulant activity (FVIII:C) levels > 122%.; 5.4 (1.6-18.6) for fasting homocysteine levels > 15.2 mumol/l: and 4.4 (1.0-18.7) for loading homocysteine levels >45.8 mumol/l. Of these disorders, only the FII mutation and hyperhomocysteinaemia significantly increased the risk of recurrence in FV Leiden carriers. The estimated recurrence rate ranged from 0.45 per 100 patient-years after a secondary first event in the absence of concomitant disorders to 4.8 per 100 patient-years when a spontaneous first event was combined with concomitant disorders, Our study provides supportive evidence that the incidence of recurrent venous thromboembolism in heterozygous FV Leiden carriers depends on the concomitance of other thrombophilic disorders. in addition to whether the first thrombotic event occurred spontaneously