HOW I DO – DVT – Treatment with CDT – PART – 13
HOW I DO – DVT – Treatment with CDT – PART – 13
(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)
Question: In last part, we covered some important points related to VTE (Deep Vein Thrombosis and Embolism) 1. Urgent treatment initiation is important in a case of VTE. Within same day if DVT, and earlier if PE. This means we do have time for thorough history and to wait for at least CBC, PT, aPTT, Creatinine, SGPT in practically all cases. 2. Most important factor in prevention of progression, recurrent VTE, Death is, not just initiating anticoagulation BUT how quickly optimal level of anticoagulation is achieved. 3. This is where LMWH is much better than regular heparin (UFH). Hence preferred in the vast majority of cases. IV heparin is suboptimal, and used in some very specific cases only e.g. low GFR, high risk for bleeding 4. Dose is weight based. Hence please ensure you are giving right dose. A fixed dose for every patient can lead to under dose or over dose. 5. Stable DVT patients can be treated as outpatient with LMWH, provided certain criteria are met.
Just to reiterate, you are suggesting that severity of DVT/PE does not matter with regard to choice of anticoagulation. Would you not prefer IV heparin in a case of massive thrombosis or a massive PE???
Answer: Thank you for asking this. This is what many clinicians still think i.e. LMWH is weaker, and IV Heparin (unfractionated heparin) is stronger. Hence bigger the clot, more likely to use IV heparin. As per the pathophysiology and mechanism we discussed last time, and based on multiple studies, LMWH IS CLEARLY SUPERIOR WITH NO DOUBT WHATSOEVR.
And remember to use weight based dosing for LMWH. I see some people writing only 0.6 ml of subcutaneous enoxaparin for all adult patients, even if their weight is 50 kg or 80 kg.
We recently had a senior consultant admitted for major pulmonary embolism, treated with LMWH only for several days. Then switched to oral anticoagulation. Same with a young man several months ago, massive PE and secondary severe pulmonary artery hypertension as well. He was in ICU. Treated with LMWH. In addition, he was also treated with clot extraction procedure by cardiologist. Another young man recently, with extensive thrombosis involving IVC extending up to iliac veins, and also renal veins bilateral with resultant significantly high creatinine. Now, this patient, due to his very low GFR, was put on IV heparin. But after several days there was no improvement in his bilateral leg edema, and renal function. Then we involved our interventional radiologist, and he did catheter directed thrombolysis with excellent results. Creatinine improved to near normal in 24 hours. Then he was put on LMWH, and later oral anticoagulation.
All three patients were treated with either cardiologist or intensivist. And in all three, we did not find any significant etiology for such extensive thrombosis. Not even obesity. But all three of them will need fairly long term anticoagulation. There is some data now to suggest that after 6 months to one year, we may be able to switch them to lower intensity of anticoagulation. But this is early data. In general, I would suggest to continue full dose anticoagulation for those who have low risk factors for bleeding. Since a second event can be fatal or disabling.
Que: Very interesting. Clearly demonstrating the clinical usage of LMWH even in the highest risk levels of DVT/PE. So, there is no confusion that LMWH is superior to IV heparin. You also mentioned about some procedures in two of the above patients. I have heard of systemic thrombolysis using t-PA or streptokinase, but this is new to me. Can you elaborate?
Ans: Sure. Technology. These are expensive, but safer than systemic thrombolysis, as the effect is limited to the involved area, rather than whole body. and seems more effective too, based on short clinical experience, while comparing with our old experience of systemic streptokinase. However systemic streptokinase is cheaper. Cather directed therapy (CDT) basically involves intervention where just like angiography or other interventional procedures, you reach out to the vessel involved, and then inject thrombolytic agent at that site. So, the local concentration is much higher, and systemic is much lower. Hence more effective, and yet safer. Procedure risk is smaller now due to many experienced cardiologists and interventional radiologists available now. Clot extraction/suction can be done at same time, depending on case details, and available expertise/special catheters.
These procedures are worth considering when there is severe pulmonary artery hypertension, or high proBNP suggesting that embolism has led to critical burden on heart, or patient has baseline low cardiopulmonary reserve due to comorbidities. Or when the thrombosis is extensive and its signs like pedal edema or organ effect is not improving even after several days. These patients even if they survive, may have very poor quality of life due to marked edema and pain in legs on ambulation, inability to stand long, may get varicose veins. This is known as post phlebitic syndrome, with variable symptom burden. For many, this can be a significant quality of life issue. Fortunately, these procedures i.e. catheter directed thrombolysis or clot extraction, work even up to about 7-14 days. Means first few days, you can try with adequate LMWH, and if it works well, procedure is not needed. In most cases, LMWH is sufficient initially, except for those who fit the definition of massive PE where heart is clearly compromised, and an additional embolism or extension of thrombosis is likely to be fatal.
July 13th 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