What is heparin resistance?

Heparin resistance usually refers to an effect of unfractionated heparin, for which doses are measured and adjusted, rather than low-molecular-weight heparin, which is not routinely monitored with laboratory testing.

How is heparin resistance treated?

Heparin resistance occurs in up to 22% of patients undergoing cardiac surgery requiring cardiopulmonary bypass and it is associated with decreased levels of antithrombin. Treatment options for heparin resistance include administration of antithrombin or fresh frozen plasma.

What causes heparin resistance?

Heparin resistance can result from increased heparin-binding protein levels (acute phase reactants), low ATIII levels (most common cause), increased heparin clearance levels (e.g. due to splenomegaly in liver disease), high factor VIII levels and factitious resistance such as when heparin is not connected to the …

Why is heparin used in cardiac surgery?

Blood is anticoagulated using a drug named heparin during open-heart surgery to allow it to safely pass through the heart-lung machine which pumps the blood throughout the body during the surgery. Each patient is given the heparin they need for their surgery.

How common is heparin resistance?

Heparin resistance is defined as the need for more than 35 000 units in a 24-hour period to prolong activated PTT in the therapeutic range. Heparin resistance occurs in up to 22% of patients undergoing cardiopulmonary bypass, and 65% of these cases are secondary to ATIII deficiency.

How does heparin work in the body?

Heparin works by disrupting the formation of blood clots in your veins. It can prevent blood clots from forming, or stop clots that have already formed from getting larger.

What is cryoprecipitate vs FFP?

FFP contains coagulation factors at the same concentration present in plasma. Cryoprecipitate is a highly concentrated source of fibrinogen.

What are the side effects of heparin?

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• Abdominal or stomach pain or swelling.
• back pain or backaches.
• bleeding from the gums when brushing teeth.
• blood in the urine.
• coughing up blood.
• headaches, severe or continuing.
• heavy bleeding or oozing from cuts or wounds.
• joint pain, stiffness, or swelling.

How much heparin is given during CABG?

In CABG with the use of cardiopulmonary bypass, routine anticoagulation consists of heparin ≥300 U/kg, aiming at activated clotting time (ACT) of ≥400 s [2, 3].

Which is used as antidote for heparin?

Expert opinion: Despite of the low therapeutic index, protamine is the only registered antidote of heparins. The toxicology of protamine depends on a complex interaction of the high molecular weight, a cationic peptide with the surfaces of the vasculature and blood cells.

What complications are associated with heparin?

Thrombocytopenia, bleeding events, and osteopenia are the 3 most common drug-related problems associated with heparin and LMWH therapy. These side effects often complicate treatment and increase the overall cost of care.

When would you use cryoprecipitate over FFP?

Cryoprecipitate is used for hypofibrinogenemia, vonWillebrand disease, and in situations calling for a “fibrin glue.” Cryo IS NOT just a concentrate of FFP. In fact, a unit of cryo contains only 40-50% of the coag factors found in a unit of FFP, but those factors are more concentrated in the cryo (less volume).

Which patients receive the highest heparin doses during cardiopulmonary bypass?

Group 3 patients received the highest heparin doses (p less than 0.05) and had the greatest postoperative blood loss (p less than 0.05). Protamine dose and heparin concentration during cardiopulmonary bypass correlated best with postoperative mediastinal drainage.

How is the clinical response to unfractionated heparin assessed?

With the use of both functional and quantitative tests, the clinical response to unfractionated heparin can be assessed to confirm circulating levels of heparin as part of a management strategy for situations in which heparin resistance is a concern.

What is the pathophysiology of heparin resistance?

Heparin resistance can be defined as a need for higher than usual doses of heparin to achieve adequate anticoagulation. This may be due to ATIII deficiency or increased protein binding of heparin. Protein binding is variable and increases in acute illness. ATIII deficiency may be either inherited or acquired (Table 2 ).

What is the role of antithrombin III in the treatment of heparin-resistant patients?

Avidan MS, Levy JH, van Aken H, et al. Recombinant human antithrombin III restores heparin responsiveness and decreases activation of coagulation in heparin-resistant patients during cardiopulmonary bypass. J Thorac Cardiovasc Surg 2005 ;130: 107 – 113.