Takayasu's arteritis associated with factor V Leiden

Epidemiology and Pathophysiology of Lower Extremity Peripheral Arterial Disease

Peripheral arterial disease (PAD), a major cause of disability, loss of work, and lifestyle changes in the United States, is defined as obstruction of blood flow into an arterial tree excluding the intracranial or coronary circulations. PAD is mostly silent in its early stages, but when lesion obstruction exceeds 50%, it may cause intermittent claudication with ambulation. Further disease progression typically leads to rest pain or frank tissue loss. However, some patients may remain asymptomatic with severe disease because of extensive collateralization in the lower extremity. Estimates of the prevalence of intermittent claudication vary by population, from 0.6% to nearly 10%; the rate increases dramatically with age. Approximately 20% to 25% of patients will require revascularization, while fewer than 5% will progress to critical limb ischemia. Limb loss, although rare, is associated with severe disability and an overall poor prognosis, with 30% to 40% mortality in the first 24 months after limb loss. As with coronary artery disease, the most common cause of symptomatic obstruction in the peripheral arterial tree is atherosclerosis, a systemic inflammatory process in which cholesterol-laden plaque builds up in the artery and eventually blocks the lumen. Typical risk factors include age, gender, diabetes, tobacco abuse, hypertension, and hyperlipidemia.

P-selectin expression, but not GPIIb/IIIa activation, is enhanced in the inflammatory stage of Takayasu's arteritis

BACKGROUND

Inflammation and thrombosis are closely related processes, but the association between disease activity and thrombogenicity in Takayasu's arteritis (TA) is poorly understood. To investigate the link between platelet activation and disease activity, flow cytometric analyses of platelet P-selectin and activated GPIIb/IIIa expression were performed in patients with TA.

METHODS AND RESULTS

Twenty-two patients with TA, classified into active (Group A, n = 9) and inactive (Group I, n = 13) according to blood-derived inflammatory markers, and 14 healthy age- and gender-matched controls (Group C) were studied. Compared with Group C, the mean fluorescence intensity of P-selectin in response to 0.1-10 micromol/L of ADP was significantly upregulated in Group A, but not in Group I. No differences in platelet GPIIb/IIIa expression in stimulated platelets were seen among the 3 groups. Standard platelet aggregation studies revealed that disease activity did not influence platelet aggregation by ADP.

CONCLUSIONS

P-selectin expression, but not activated GPIIb/IIIa, is enhanced in ADP-activated platelets from patients in the inflammatory stage of TA. P-selectin may play a significant role in the inflammatory and thrombotic responses associated with intractable TA, presumably by inducing platelet-leukocyte interactions.

Epidemiology and pathophysiology of lower extremity peripheral arterial disease

Peripheral arterial disease (PAD), a major cause of disability, loss of work, and lifestyle changes in the United States, is defined as obstruction of blood flow into an arterial tree excluding the intracranial or coronary circulations. PAD is mostly silent in its early stages, but when lesion obstruction exceeds 50%, it may cause intermittent claudication with ambulation. Further disease progression typically leads to rest pain or frank tissue loss. However, some patients may remain asymptomatic with severe disease because of extensive collateralization in the lower extremity. Estimates of the prevalence of intermittent claudication vary by population, from 0.6% to nearly 10%; the rate increases dramatically with age. Approximately 20% to 25% of patients will require revascularization, while fewer than 5% will progress to critical limb ischemia. Limb loss, although rare, is associated with severe disability and an overall poor prognosis, with 30% to 40% mortality in the first 24 months after limb loss. As with coronary artery disease, the most common cause of symptomatic obstruction in the peripheral arterial tree is atherosclerosis, a systemic inflammatory process in which cholesterol-laden plaque builds up in the artery and eventually blocks the lumen. Typical risk factors include age, gender, diabetes, tobacco abuse, hypertension, and hyperlipidemia.