HOW I DO – Surgical Clearance With Low Platelet or High PT – PART – 8
HOW I DO – Surgical clearance with low platelet or high PT – PART – 8
(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)
Question: In last part, we covered some important points related to surgical clearance for patients on antiplatelets or anticoagulation. 1. All antiplatelet agents are not same. Aspirin related risk is much lower compared to newer antiplatelets. For urgent surgery, platelet can be transfused. Otherwise wait for 2-7 days. Bone marrow biopsy, pleural/ascitic tapping does not require any wait time. No tests can predict bleeding reliably, hence not indicated for any decision making. 2. Be careful while evaluating medication list. Many new medicines in these categories with so many brand names. Patient may not recognize them as Blood Thinner. 3. Anticoagulation is a much higher bleeding risk, even for small procedures like bone marrow biopsy, pleural/ascitic tapping etc. Different drugs need different wait time before surgery. E.g. warfarin about 5 days, but most NOAC about 24 hours. Tests for prediction of bleeding are well known for warfarin or acitrom i.e. PT. but for NOAC, anti factor Xa, which is not widely available except in major cities and that too few labs. 4. For emergency procedures, different preparations are required for 3 different classes of drugs i.e. warfarin/acitrom; NOAC; heparin/LMWH. Need to be carefully planned. Vitamin K alone is not sufficient. Not even FFP given once. There are specific antidotes for some of the medicines. You provided excellent clarity in last part about this very common practice scenario, and with ever growing list of medicines.
But what if any tests are abnormal, such as low platelet? Or high PT, aPTT?
Answer: Thank you. Before we start, one important point that many people ask about.
Antiplatelet agents do NOT reduce platelet number, only reduce their function. Means if patient is on antiplatelet agent and platelet counts are low, they must be investigated for the etiology of low platelet.
If platelet count is low, you need to look at following main considerations:
- How is the other pillar of Hemostasis i.e. PT, aPTT. If this is normal, risk is lower. If this is also abnormal, risk is substantially higher.
- How severe?
- How invasive is the procedure, or surgery required?
Severity of thrombocytopenia:
MILD is 100,000 to 150,000. At this level, practically all surgeries can be allowed, provided PT, aPTT are normal. We give formal clearance for even CABG, Neurosurgery at this level.
MODERATE is about 30,000 to 100,000. This is a wide range. For bone marrow biopsy, pleural or ascitic tapping, lumbar puncture, CVP line, this is ok. Also about 50,000 platelet is sufficient for hernia surgery or appendix removal.
SEVERE is below 30,000. At this point, bone marrow biopsy is ok, but for other procedures, individualized decision making is required. And surgery definitely requires a specialist input. This is important since every patient with low platelet will not respond to platelet transfusion.
Etiology of low platelet also matters somewhat i.e. in case of ITP, platelets are generally much more functional and hence bleeding risk is lower. But for same platelet count, myelodysplastic syndrome patient is more likely to bleed.
Expertise of the person doing procedure also matters e.g. lumbar puncture at 30,000 is ok with an expert who gets it in one prick almost always. For others, over 50,000 should be the goal. At some institutions in USA, who routinely treat pediatric acute leukemia, they do lumbar puncture at 10,000 too!! Similarly, for a CVP line insertion, 10,000 to 30,000 is ok with expert, but otherwise goal should be over 50,000.
Que: That is very interesting and helpful. What about for those who have high PT and/or aPTT?
Ans: This is more complex, since the bleeding risk is significantly higher. And depends largely on the underlying reason too. For example, if tests are abnormal due to chronic liver disease/cirrhosis, ascitic tapping or bone marrow biopsy, CVP line insertion can be done with very low risk. But risk is significantly higher with most other etiologies e.g. DIC, anticoagulation drugs.
They need expert involvement for planning of blood products and other aspects before and after surgery. Vitamin K is frequently given for any high PT in routine practice. However, it works only for vitamin K deficiency, not for other etiology. Pure vitamin K deficiency is uncommon. Such as patients with prolonged hospitalization requiring broad spectrum antibiotics. These patients require only 2-5 mg vitamin k to completely correct PT in about 12 hours. Higher doses do not lead to more correction. Higher doses up to 30 mg are generally given to provide longer term storage of vitamin k, not for better correction. Means, if you have given first dose of 10 mg, and next day your PT is still high, you need to look for other reasons. Further vitamin k is not going to solve your problems. Most common other etiology for high PT is chronic liver disease/cirrhosis. Then medicines, DIC etc. High aPTT alone is a whole different topic, and requires separate evaluation and management.
February 9th, 2024
Dr Chirag A. Shah; M.D. Oncology/Hematology (USA), 9998084001. Diplomate American Board of Oncology and Hematology. Ahmedabad. drchiragashah@gmail.com www.shyamhemoncclinic.com