HOW I DO – PVT, Pregnancy – PART – 18

HOW I DO – PVT, Pregnancy – PART – 18

(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)

Question: In last part, we covered additional important points related to DVT of specific sites 1. Distal leg i.e. calf DVT has very low risk of pulmonary embolism. These patients can be observed with monitoring, especially if no other major risk factors for DVT. 70% would progress to promixal DVT however. But 30% can be spared anticoagulation and its risk. 2. Upper extremity DVT – treated same as leg proximal DVT nowadays. 3. CVTS – cerebral venous sinus thrombosis – fortunately, most people have excellent neurological recovery, if treated in time. Requires about 3-6 months of anticoagulation only. Very high homocysteine is a risk factor in India, likely due to B12 or folic acid deficiency as the most common cause. 4. Mesenteric vein thrombosis – to rule out myeloproliferative neoplasm in these cases, even if cbc is normal. Lifelong anticoagulation is advisable, even if no risk factor is found.

Very interesting to note the differences in management of specific sites. Especially intriguing was cerebral vein thrombosis. This requires only 3-6 months of anticoagulation, while proximal leg vein thrombosis with no risk factor, you advise anticoagulation for so much longer, frequently years. Any other site that we should discuss?

Answer: Yes. Portal vein thrombosis is another interesting, intriguing site. In our practice, PVT is seen in mainly 3 scenarios.  1. Associated with HCC i.e. hepatocellular carcinoma. In higher stages, portal vein is involved with either right or left portal vein and then main portal vein in more advance stage. This however is primarily tumor thrombus, hence we don’t consider anticoagulation here. Nowadays we increasingly consider Radiotherapy just for portal vein thrombus in such cases. To open the vein, by clearing tumor.

2. Chronic portal vein thrombosis, mostly with cavernoma formation (venous collaterals forming a cluster around blocked vein). Once collaterals are formed, it means thrombus is old and will not resolve with anticoagulation. Such patients present to us either as incidental finding or due to effects of hypersplenism (low cbc or large spleen related symptoms, variceal bleed). These patients require work up for underlying cause, especially to rule out myeloproliferative neoplasm or other major risk factors for thrombosis. If there is a risk factor, anticoagulation is considered. However one has to balance risk of bleeding if varices or low platelet due to hypersplenism. In practice, these patients are generally not given anticoagulation.
3. Acute portal vein thrombosis. Fortunately, these are fairly uncommon. But are an emergency like any other DVT. Requires anticoagulation, same concepts as other DVT. And evaluation for underlying risk factor. Same as mesenteric vein thrombosis, look for myeloproliferative neoplasm even if cbc is normal. And for cirrhosis, PNH paroxysmal nocturnal hemoglobinuria, apart from the standard list of risk factors e.g. APLA.

Que: What about DVT during pregnancy? How to manage during pregnancy, labor, breastfeeding?

Ans: A very important and a wide topic. But key points are: 1. DVT that develops during pregnancy or postpartum period, is managed with anticoagulation upto about 3-6 months post pregnancy. 2. LMWH is preferred during pregnancy, especially first trimester. Second and third trimester, warfarin can be given. No role for DOAC during pregnancy or breastfeeding. If cost is an issue, UFH (old heparin) can be used subcutaneous. Also, near delivery time, LMWH or warfarin is stopped, and UFH is preferred. As it has shorter half life and can be rapidly reversed with protamine if required in case of bleeding. Consider monitoring anti Xa activity few times to ensure optimum anticoagulation, much more so in obese pregnant patients. 3. For those who had been on anticoagulation and became pregnant, immediately stop warfarin or DOAC. And switch to LMWH or UFH. 4. Post delivery, one can restart LMWH or UFH about 6-12 hours after delivery depending on bleeding risk, and normal versus C section delivery. 5. During breastfeeding, DOAC are not used. LMWH, UFH, Warfarin are safe. 6. An extremely important point specific to pregnancy is to avoid use of Epidural anesthesia as far as possible. If it is used, a very careful planning is required with regard to timing of when to stop and restart anticoagulation. A very significant risk of spinal hematoma and resultant paraplegia is there if epidural catheter is placed while patient is even partially anticoagulated. Warfarin effect takes about 5 days to clear. LMWH about 24 hours. Keeping patients off anticoagulation for long may not be advisable, for patients at high risk for recurrent thromboembolism. 7. For patients with prosthetic heart valve, or some patients with APLA, and few other patients, warfarin is preferred. For such patients, decision making is very complex. And requires detailed counseling and patient involvement to decide type of anticoagulation. Warfarin is preferred here for maternal safety, but first trimester warfarin means higher chance of fetal abnormality. As doctors however our preference is maternal safety first. 8. For those who have a history of DVT but not requiring anticoagulation now, or have a strong risk factor, such as APLA, and now become pregnant. They require prophylaxis, preferably with LMWH. If cost is an issue, then UFH. Dose depends on weight. But generally standard enoxaparin 0.4 ml subcutaneous is used. For lower risk patients, this may not be given throughout pregnancy, but at least 3^rd trimester, and postpartum six weeks. Postpartum is the highest risk period.

December 14^th 2025

Dr Chirag A. Shah; M.D. Oncology/Hematology (USA), 9998084001. Diplomate American Board of Oncology and Hematology. Ahmedabad. drchiragashah@gmail.com   www.shyamhemoncclinic.com