The hypercoagulability states

Atherosclerosis and secondary deep vein thrombosis: a difficult correlation

The aim of this study was to verify the degree of atherosclerosis in a group of subjects affected by secondary deep vein thrombosis and in a matched control group. Sixty-three patients were studied. Of these, 19 were cases (mean age 62.2 +/- 1.2) and 16 were controls (mean age 59.3 +/- 2.7). Twenty-eight were excluded because they were affected by hyperhomocysteinemia. The arterial tree was examined by means of echo color Doppler, and the intima media thickness and the presence of and degree of plaques bilaterally in the carotid and femoral artery and abdominal aorta were measured with a computerized method. No difference was found in the 2 groups as concerns intima media thickness or plaques in the arterial district explored. Secondary deep vein thrombosis is not a greater risk factor for atherosclerosis.

Plaque rupture with severe pre-existing stenosis precipitating coronary thrombosis. Characteristics of coronary atherosclerotic plaques underlying fatal occlusive thrombi

Ruptured atheromatous plaques were identified by step-sectioning technique as responsible for 40 of 51 recent coronary artery thrombi and 63 larger intimal haemorrhages. The degree of pre-existing luminal narrowing at the site of rupture was decisive for whether plaque rupture caused occlusive thrombosis or just intimal haemorrhage. If the pre-existing stenosis was greater than 90% (histologically determined) then plaque rupture nearly always caused occlusive thrombosis. Clearly indicating the primary role of plaque rupture in thrombus formation were the frequent finding of plaque fragments deeply buried in the centre of the thrombus and the nature of the thrombus at the site of rupture where it consisted predominantly of platelets. Thus, a severe chronic stenosis seems to be a prerequisite for occlusive thrombus formation, but the thrombotic process itself is triggered by an acute intimal lesion.

Venous and arterial thromboembolic disease in women using oral contraceptives

Vascular plasminogen activator was measured by means of a new chromogenic assay in 24 women who had suffered from oral contraceptive-associated thrombotic disease and was compared to that in a control group of 78 premenopausal women. Vascular plasminogen activator levels were significantly reduced in the subjects who had venous thrombosis but not in the five women who had arterial thrombosis (0.04 +/- 0.03 versus 0.38 +/- 0.31, respectively) when compared to the levels in the control group (0.19 +/- 0.20). Since vascular activator levels distribute in a non-Gaussian manner, cases and controls were also stratified into deciles. Seventeen subjects who had suffered from venous thrombosis were stratified in the lowest three deciles, and two subjects, in the fourth and fifth deciles. Subjects who had suffered from arterial thrombosis were in the fourth or higher deciles. The conclusion is that, although there is a correlation between low levels of vascular plasminogen activator and venous thrombosis, no such correlation exists for arterial thrombosis.