A clinically significant antiphospholipid antibody (aPL) profile means that your blood has tested positive multiple times (at least twice and 12 weeks apart) for one or more of the aPL tests below:
Higher levels of aCL and aβ2GPI (especially higher than 40 units) correspond to an increased risk of an aPL-related event; lower levels are clinically less important (especially levels lower than 20 units). Patients who are positive for all three of the aPL blood tests seem to have a higher likelihood of an aPL-related event than those with only one or two positive tests.
Antiphospholipid syndrome is an autoimmune disorder in which autoantibodies, i.e., antiphospholipid antibodies, lead to blood clots and miscarriages. Some of the other clinical problems related to aPL include livedo reticularis (lacey purple pattern on skin), heart valve disease, low platelet count, anemia, and kidney disease.
Different types of aPL-positive patients include:
Many people can have aPL in their blood without developing blood clots. However, a “trigger” can initially damage a blood vessel, which is followed by aPL binding, inflammation, and the formation of a blood clot. Some of these “triggers” include smoking, oral contraceptive pills, hormone replacement therapy, traditional cardiovascular disease risk factors (high blood pressure, high cholesterol, and diabetes), and surgical procedures.
Surgery is a major risk factor for the formation of blood clots in everyone. Two factors contribute to the risk:
Antiphospholipid antibody positive patients are at higher risk for blood clots compared to the general population because of a third factor:
It is also important to understand that not every surgical procedure has the same clotting risk: minor surgeries, e.g., dermatologic (skin) or ophthalmologic (eye) procedures, are less risky than major surgeries, e.g., abdominal surgeries or joint replacement surgeries.
It is vital for aPL-positive patients to understand the risks associated with surgery. Only absolutely necessary surgical procedures should be conducted.
You should let your surgeon know if you are aPL-positive and/or if you have been diagnosed with APS so that he/she is aware of your increased risk of clotting. It is critical that your surgeon communicate with your rheumatologist or hematologist to develop a risk-benefit assessment for your surgical procedure as well as a management plan (medications and other prevention methods before and after surgery) to decrease the risk of blood clots.
Many APS patients are on long-term blood-thinning medication such as warfarin (Coumadin ®). This creates a challenge for surgery because warfarin can take several days to wear off. Doctors will often use a strategy called “bridging” where a long-acting warfarin is replaced with a short-acting medication called heparin around the time of surgery. You might be given the injection form of heparin (e.g., enoxaparin [Lovenox ®]) to use at home or an intravenous form of heparin in the hospital before/after surgery. The intravenous form of heparin can be “turned off” quickly to prevent bleeding during surgery.
For APS patients on long term warfarin, the ultimate goal is to keep the blood thin for as long as possible to protect against clots, then to bring the blood to a normal clotting level temporarily during the surgery to prevent blood loss. It is very important to minimize the time spent off blood-thinning medications, so warfarin and/or heparin should be restarted as soon as it is safe to do so after surgery.
It is important to discuss every medication that you take so that your doctor can devise a plan to withhold or change the dose of certain medications. Medications that require special attention include:
Because prolonged immobility can increase the risk of developing a blood clot, patients should be very careful to minimize immobility following surgery. Patients and their family members/caregivers should be familiar with the early signs of a blood clot, which include numbness, swelling, or sudden onset of pain in the legs and arms, as well as shortness of breath, chest pain, coughing blood or blood-streaked mucous, paralysis or weakness of the face or limbs, slurred speech, and visual changes. Patients should contact their doctors as soon as possible if they develop any of these symptoms.
Antiphospholipid antibody-positive patients undergoing kidney transplant surgeries are at increased risk for kidney failure and graft failure even if they have never had blood clots.
Neurosurgery and spine surgeries can be particularly challenging for aPL-positive patients because potential bleeding can result in major complications.
Patients should always discuss their individual conditions and risks with their doctors.
You should always speak with your doctor about your risks of cardiovascular disease (CVD) and about preventive medications or lifestyle changes that can decrease your chances of CVD specific to your needs.
Volunteer, Hospital for Special Surgery
Katherine H. Saunders, MD
Resident Physician, Department of Internal Medicine, New York-Presbyterian Hospital