Covid-19 May Increase Risk of Deep Venous Thrombosis (DVT)

A soon to be published article in the Journal of Vascular Surgery Venous and Lymphatic Disorders noted an increase in the number of cases of deep venous thrombosis (DVT) in patients hospitalized with Covid-19. Granted this was an anecdotal study from one hospital in Italy, but the findings are significant. DVT and pulmonary embolism (PE) result in a significant number of hospital deaths. 

The authors hypothesize several reasons for this increased incidence of DVT. First, all hospitalized patients are at increased risk for DVT because they are immobile. Second, the Covid-19 infection may result in the release of inflammatory molecules which can injure the lining of  veins and thus increase the risk of DVT. Finally, the infection can possibly increase procoagulant factors which increase the risk of blood clotting. This covers all 3 of the major risk factors for developing a DVT know as Virchow’s Triad: venous stasis, endothelial injury, and hypercoagulability. 

All Hospitalized Patients are at Risk of DVT

It is important to realize that all hospitalized patients are at increased risk for DVT. There are several reasons for this. Most importantly, patients in the hospital spend most of their time in bed, immobile. Next, many patients have underlying medical conditions, such as infections, that make them more likely to form blood clots. In addition, many patients have had surgery which put them at increased risk of DVT. Patients who have had orthopedic procedures, abdominal or pelvic surgery, or complex cardiovascular procedures are all at increased risk of DVT. 

The Good News for Hospitalized Patients

Because the risk of DVT in hospitalized patients is high and can result in death and long-term disability, physicians are careful to make sure that all hospitalized patients have measures taken to prevent DVT. For example, with electronic medical records, “hard stops” are established where the physician writing orders is forced to address DVT prophylaxis.

Multiple steps are taken in hospitalized patients to prevent DVT and PE. Patients who do not have a contraindication to blood thinners generally receive SQ  heparin or Lovenox during their hospitalization to prevent blood clotting. Increasing blood flow in the veins also helps prevent DVT. There are several ways that this is accomplished. Compression stockings help veins empty more efficiently and prevent pooling of blood in the veins. Early ambulation is also useful to increase blood flow. Perhaps the simplest method to increase blood flow is by elevating your legs above your heart. Multiple studies have shown this to be effective in helping to prevent DVT.*

After Hospital Discharge

The risk of DVT often remains high even after discharge from the hospital. There are several reasons for this. First, if you have just had surgery you may still be less active. In addition, after surgery or any major injury your blood may be hypercoagulable (more likely to clot). These issues are important given that the trend is for early hospital discharge. 

Fortunately, after being discharged from the hospital there are steps that you can take to prevent DVT. 

  1. Gradually increase your normal activity. Walking specifically increases venous blood flow by activating the calf muscle pump. 
  2. Elevate your legs. Leg elevation allows you to take advantage of gravity to increase blood flow in your veins which prevents blood clots and helps dissolve any clots that you may have. Leg elevation also reduces leg swelling which is common after many procedures. However, leg elevation is only effective if done correctly. [photo of LDLR]
  3. Wear compression stockings. Compression stockings help prevent pooling of blood in your veins (venous stasis) and are especially important to wear when you will be standing or sitting for a prolonged time. 
  4. Stay hydrated. Dehydration increases your risk of blood clots so drink plenty of water and stay hydrated. 


A DVT can result in debilitating long-term consequences. Hospitalized patients are especially at risk. However, you can prevent DVT by being mindful of your venous health. Keep that venous blood flowing. Elevate your legs daily. Wear your compression stockings. Exercise and avoid prolonged sitting and standing. These are things that should be part of your daily routine regardless to help lower the risk of developing vein problems. 

Author; Dr. Chris Dickson, Board Certified Vascular Surgeon & Inventor of the Lounge Doctor Leg Rest. 

  • Ashby EC. Leg elevation in prophylaxis of thromboembolism. Lancet. 1993;342(Dec):1562-3.
  • Scholz PM, Jones RH, Wolfe WG, et al. Prophylaxis of pulmonary embolism. Major Prob Clin Surg. 1980;25:96-111.
  •  Tsapogas MJ, Miller R, Peabody RA. Detection of postoperative venous thrombosis and effectiveness of prophylactic measures. Arch Surg. 1970;101:149-54.
  • McLachlin AD, McLachlin JA, Jory TA, et al. Venous stasis in the lower extremities. Annals of Surg. 1960;152(4):678-83

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