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Thrombotic disorders Inherited thrombophilia
ОглавлениеFifteen to 25% of Caucasian populations have thrombophilic risk factors. Heritable thrombophilias include deficiencies of the endogenous anticoagulants, antithrombin, protein C and protein S, and genetic mutations in procoagulant factors such as factor V Leiden and prothrombin G20210A, and the thermolabile (C677T) variant of the methylene tetrahydro‐folate reductase (MTHFR) gene. The prevalence of these thrombophilias is variable, with significant ethnic variation. For example, 2–7% of Western European populations are heterozygous for factor V Leiden and prothrombin G20210A compared with less than 1% of Chinese.
Table 8.1 Risk factors for venous thromboembolism (VTE) [8].
| History markers | |
|---|---|
| Previous venous or arterial thromboembolism | |
| Obesity (body mass index ≥30 kg/m2) | |
| Gross varicose veins | |
| Previous/current intravenous drug abuse | |
| Age over 35 years | |
| Parity >=3 | |
| Smoker | |
| Ovarian hyperstimulation syndrome | |
| Dehydration | |
| Immobility | |
| Prolonged bed rest | |
| Prolonged travel | |
| Medical conditions (such as infections, malignancies, cardiac conditions, active systemic lupus erythematosus, inflammatory bowel disease, sickle cell disease, type 1 diabetes with nephropathy, nephrotic syndrome etc.) | |
| Inherited thrombophilia | Odds ratio for VTE (95% confidence interval) |
| Factor V Leiden heterozygous | 9.2 (5.44–12.70) |
| Factor V Leiden homozygous | 34.40 (9.86–120.05) |
| Antithrombin deficiency | 4.69 (1.30–16.96) |
| Protein C deficiency | 4.76 (2.15–10.57) |
| Prothrombin G20210A heterozygous | 6.80 (2.46–19.77) |
| Prothrombin G20210A homozygous | 26.36 (1.24–559.29) |
| Family history of VTE in one or more first degree relatives | 2.7 (1.8–3.8) |
| Acquired thrombophilia | |
| Lupus anticoagulant | |
| Anticardiolipin antibodies |
