Thrombotic events in patients with antiplatelet factor 4/heparin antibodies

Abstract

Patients who develop antibodies to the PF4/heparin complex have a significantly higher rate of thrombotic events during a one-year follow-up than those who lack these antibodies; within this group the risk of developing thrombosis increases with increasing plasma concentration of antibodies.

Elevated Heparin Induced Antibodies are More Common in Diabetic Patients With Vascular Disease

“…In this at risk population, an elevated HPF4 antibody was present in 30% of DM and 12% of nDM (chi-squared test < 0.04) without evidence of thrombocytopenia. The presence of HPF4 antibodies without clinical evidence of HIT is not uncommon and our series shows a range consistent with previous reports [10,12,14].…”

“…In addition, patients who had been previously treated with unfractionated heparin as part of cardiac surgery management and had developed HPF4 antibodies were more likely to die or develop myocardial infarction, pulmonary embolism, or stroke than patients who were antibody negative. These patients retained a higher thrombotic event rate up to a 1-year followup [14].…”

The identification and management of heparin-induced thrombocytopenia in the vascular patient

“…23 Although venous thrombosis in HIT appears to be more common in orthopedic patients, cardiovascular patients show a similar prevalence of venous and arterial thromboses. 3,29 Arterial thrombosis in HIT most commonly affects larger arteries in the lower limbs (10%-15%), 29 whereas thrombotic stroke (5%-10%) 50,51 and myocardial infarction (3%-5%) 52 are common but less prevalent. 44,53 Clinical complications of HIT other than thrombosis.…”

Heparin-Induced Thrombocytopenia in Cardiovascular Patients

“…The thrombotic risk continues after the cessation of heparin and even after the platelet counts return to normal. 13 The most common site of thrombosis is deep venous thrombosis of the lower extremities. 44 Pulmonary embolism is often life threatening, and comprises 25% of mortality in HIT patients.…”

“…12 About 3% of patients with platelet factor 4 (PF4)/heparin antibody have thrombosis in either arteries or veins. 13 Interestingly, in cardiothoracic or orthopedic surgery cases receiving heparin, the prevalence of anti PF4/ heparin antibody is much higher (more than 25%) compared with nonsurgical exposure to unfractionated heparin or LMWH. 14 The mechanism is thought to be a costimulatory effect of B cells by proinflammatory factors during major surgeries.…”