relationship between dislipidemia and thrombosis yet unproven

Lipoprotein(a): an emerging cardiovascular risk factor

Lipoprotein(a) is a cholesterol-enriched lipoprotein, consisting of a covalent linkage joining the unique and highly polymorphic apolipoprotein(a) to apolipoprotein B100, the main protein moiety of low-density lipoproteins. Although the concentration of lipoprotein(a) in humans is mostly genetically determined, acquired disorders might influence synthesis and catabolism of the particle. Raised concentration of lipoprotein(a) has been acknowledged as a leading inherited risk factor for both premature and advanced atherosclerosis at different vascular sites. The strong structural homologies with plasminogen and low-density lipoproteins suggest that lipoprotein(a) might represent the ideal bridge between the fields of atherosclerosis and thrombosis in the pathogenesis of vascular occlusive disorders. Unfortunately, the exact mechanisms by which lipoprotein(a) promotes, accelerates, and complicates atherosclerosis are only partially understood. In some clinical settings, such as in patients at exceptionally low risk for cardiovascular disease, the potential regenerative and antineoplastic properties of lipoprotein(a) might paradoxically counterbalance its athero-thrombogenicity, as attested by the compatibility between raised plasma lipoprotein(a) levels and longevity.

Hyperlipidaemia and venous thromboembolism in patients lacking thrombophilic risk factors

To ascertain the potential contribution of serum lipids to the development of deep vein thrombosis (DVT), a case-control study was conducted in 143 DVT patients lacking thrombophilic risk factors and in 194 age- and sex-matched controls. DVT patients showed significantly higher body mass indices (BMI), and triglyceride levels than did controls (P < 0.001 and P = 0.045 respectively). Using multivariate analysis, BMI was the only variable which remained statistically different, thus the risk of DVT was associated with obesity (odds ratio = 2.49). These results were confirmed when additional control for fibrinogen and plasminogen activator inhibitor type 1 (PAI-1) was carried out in a subgroup of cases and controls. When idiopathic (n = 39) and secondary (n = 104) patients with DVT were compared, the former showed a higher mean age, a higher proportion of men, and higher cholesterol levels. Age, sex and total cholesterol were statistically different by multivariate analysis. After age was dichotomized as >or= 50 years and cholesterol >or= 5.69 mmol/l, all three variables constituted independent risk factors for idiopathic DVT, with odds ratios of 2.73 for ages >or= 50 years; 3.72 for men and 2.67 for cholesterolaemia >or= 5.69 mmol/l. Obesity thus constitutes an independent risk factor for DVT, possibly in part mediated through triglyceride, fibrinogen and PAI-1 effects on haemostasis. In addition, cholesterolaemia levels of >or= 5.69 mmol/l constitute an independent risk factor for idiopathic DVT.