HOW I DO – DVT – PROPHYLAXIS – PART – 15
HOW I DO – DVT – PROPHYLAXIS – PART – 15
(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 1. IVC filter placement indications, limitations, role of filter removal in 14-28 days to reduce long term risks. Indicated not for every major DVT, but for patients with very low cardiopulmonary reserve OR when anticoagulation is contraindicated for any reason e.g. due to low platelet count. 2. DOAC, new oral anticoagulants are preferred in most cases where earlier warfarin was used. DOAC do not require PT monitoring. Kind of LMWH replacing IV heparin for most indications – not requiring frequent monitoring, and more reliable anticoagulation.3. However, for few indications warfarin or acitrom, old agents are still preferred i.e. Low GFR; APLA; Mechanical heart valve. 4. Since reliable PT monitoring is not widely available across India, DOAC are very useful. 5. Role of INR in monitoring warfarin, compared with PT. 6. Diet related myths with warfarin. TRUTH is these patients can take essentially any diet, as long as there are no dramatic changes. Any stable diet is ok. Do check for drug interactions.
Anything else you would like to discuss about DVT/PE? Any important points left?
Answer: YES. One important point we have not covered is Prevention of DVT. A huge number of trials have established the value of DVT prophylaxis in hospitalized patients especially. This has led to a significant reduction in number of DVT in western world. Clinical pathways and so many systems have been built around concept of DVT prophylaxis to ensure that all patients at risk for DVT receive adequate prophylaxis. Patients at highest risk are those hospitalized for various illnesses. Outpatient risks are much smaller comparatively, and hence not frequently considered for prophylaxis, except in some specific situations. For example, long air travel. Long is defined as over four hours of air travel. Means essentially international air travel. How much and what type of prophylaxis is highly variable here. A very interesting survey of hematologists who travelled to annual meeting of American Society of Hematology, was done. About 50 percent took some kind of prophylaxis, others did not. Among those who did, it was LMWH one injection before travel to oral DOAC with wide variations in dosages and frequency as well. Most important recommendation today for prevention of DVT with long air travel is – keep good mobility, hydration, avoid alcohol. For high risk patients, such as those with cancer, medication may be more important in addition to these measures.
MOST IMPORANT VALUE HOWEVER IS FOR HOSPITALIZED PATIENTS. Who should receive DVT prophylaxis among these patients? Following is the list of high risk patients who must receive prophylaxis.
1.Knee or Hip replacement surgery. These patients are at the highest risk, and almost always are given prophylaxis. Using most commonly LMWH. Some use Fondaparinux instead, another subcutaneously given anticoagulation.
2.Sugery involving pelvis. Cancer surgery. Patients with Cancer.
3.Stroke, or other reasons for prolonged immobilization. 4. Elderly, especially over age 75 or so.
5.Congestive heart failure. Reduced GFR – poor kidney function. Patients in ICU. Acute MI.
6.Obesity. Pregnancy. 7.Previous DVT/PE. Known case of hypercoagulable state
More the risk factors from above list, higher the risk. For example, an elderly man with obesity, renal failure, stroke, is at much higher risk than with individual risk factors alone. Certain risk assessment tools are available to understand individual patient risk for DVT and separate tools to assess risk for bleeding. These are helpful but most clinicians use above list of high risk factors, and general judgment to decide whether to give DVT prophylaxis. A short planned admission for a day for example, in an otherwise healthy adult, for a procedure or medical reason with none of the above noted risk factors, are not given prophylaxis. Some patients are intermediate risk, where guidelines recommend prophylaxis, but there is wide variation in practice, especially in India. Considering traditionally we seem to have a lower incidence of DVT compared to western population. However our lifestyle, and risk factors are fast changing. Also we do not have reliable data of DVT incidence in our population. Indian studies have shown wide variations in incidence.
Que: “VTE (venous thromboembolism), is the Number 1 Preventable cause of Death in hospitalized patients.” This is the quote from our 10th article in this series. It is therefore a very important topic, how to prevent DVT in hospitalized patients. What methods are used to prevent DVT? And risks of these methods, if any?
Ans: Large majority of patients receive LMWH, for example Enoxaparin 0.4 ml once a day subcutaneous. Other LMWH agents, Fondaparinux etc have also been studied and used by some people. Some people also prefer mechanical compression devices, but they have largely fallen out of favor, due to lower efficacy compared to LMWH, and also significantly cumbersome to use. LMWH is fairly safe, except when GFR is very low, or with spinal procedures, patients with bleeding especially intracranial. Other than some very specific situations, large majority of patients can safely receive once a day LMWH prophylaxis. Most people stop it once patient is discharged. Some stop when patient is clearly ambulatory. With low GFR, Unfractionated heparin (old heparin) can be used. When LMWH, Heparin both are contraindicated, mechanical compression devices should be used.
9th September, 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