• Study reports abnormally high VTE and high bleed risk in critically ill COVID-19 patients and calls for more effective prevention strategies.
  • Clinicians at NHS hospitals are supporting the care of COVID-19 patients with the use of geko™ devices to reduce the risk of blood clots in the most at risk patients.
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Lower Limb DVT in Hospitalized Patients with COVID-19

5th June 2020

SARS-CoV-2 (Covid-19) is now believed and widely reported to be a thrombotic and vascular disease targeting endothelial cells, causing micro-clotting and organ failure, particularly in patients with comorbidities and associated endothelial dysfunction1 – with extensive use of therapies to stabilise and protect the endothelium, such as anti-inflammatory and anti-cytokine drugs2, alongside blood thinners and clot busting drugs to prevent the micro-clots3.


Much less reported, but emerging, is lower limb Deep Vein Thrombosis (DVT) and resultant Pulmonary embolism (PE) in hospitalized C-19 patients. A recent study by Zhang L. et al4 has demonstrated that lower limb thrombosis, in the deep veins, is associated with hospitalized C-19 patients.  The study, performed in a large referral and treatment centre, evaluated lower limb DVT prevalence, risk factors, prognosis, and potential thromboprophylaxis strategies.

A cohort of 143 hospitalized C-19 patients were assessed. Lower-extremity DVT was observed in 46.1% of patients. Among patients with a Padua Prediction Score ≥4 who underwent ultrasound ˃72 hours after admission, the rate of DVT was 34.0% in those receiving venous thromboembolism prophylaxis versus 63.3% in those not receiving prophylaxis. Patients with DVT (symptomatic and asymptomatic) had a worse prognosis than patients without DVT, including more admissions to the ICU (18.2% vs 3.9%; P = 0.005), fewer discharges (48.5% vs 77.9%; P < 0.001), and more deaths (34.8% vs 11.7%; P = 0.001). Patients with DVT were older with a lower oxygenation index and a higher rate of cardiac injury.

The study concludes that the prevalence of lower limb DVT among C-19 hospitalized patients is high, and DVT is associated with unfavourable outcomes. C-19 hospitalized patients are at an increased risk of DVT due to multiple comorbidities, invasive tests and treatments, and prolonged immobilization. The paper calls for lower limb VTE prophylaxis strategies to protect high-risk patients.

The main therapies used to prevent DVT in admitted C-19 patients is anti coagulation (blood thinners). While low dose blood thinners are considered low risk, giving larger doses can cause excessive bleeding with poor clinical outcomes5. C-19 coagulation guidance therefore advocates stepping-up preventative dosing but reinforces the need for individual patient bleed risk assessment5. The guidance also supports use of mechanical prophylaxis devices in combination with drugs or when drugs and other mechanical compression devices are impractical or contraindicated.

A new, clinically proven mechanical therapy in use to prevent DVT in acute stroke patients is the innovative geko™ device6. Recommended by NICE7 and cleared by the FDA8, geko™ is a small, battery powered, disposable, neuromuscular electro-stimulation device that is applied non-invasively to the skin over the common peroneal nerve at the side of the knee. It gently stimulates the nerve, once every second, activating the calf and foot muscle pumps resulting in increased blood flow in the deep veins of the calf9, at rate equal to 60%10 of walking without the patient having to move.

Highly portable, the geko™ device is:

  • Disposable – no need to sterilise after single patient use.
  • No decontamination required – not the case with other mechanical devices.
  • Easy-to-fit – minimal training.
  • Less nurse-to-patient contact time – reduced exposure to C-19 viral load.
  • No tripping hazard – no leads or hoses.

The geko™ device is also clinically proven to improve endothelial function11, through its  systemic blood flow increase, exerting laminar (steady) shear stress on endothelial cells, releasing protective substances, such as nitric oxide and prostacyclin and the production of anti-thrombotic, pro-fibrinolytic and vasodilation agents to help combat C-19 micro- clotting. Link to blog: https://www.gekodevices.com/news-events/covid-19-potentially-an-endothelial-disease/

About DVT

DVT occurs when a blood clot forms in a large vein, usually in the calf. Swelling, pain and serious complications, such as PE (a sudden blockage in the lung) can occur and makes DVT a potentially fatal condition. Rapid treatment is imperative. DVT formation is attributed to the three major risk factors of Virchow’s triad: venous stasis, vessel injury and hypercoagulability12.

Geko™ device evidence – VTE prevention

A real-world study conducted in the UK National Health Service shows the geko™ device is clinically proven to prevent VTE6. 1,000 immobile, hyper-acute stroke patients had their contraindication and/or intolerance to IPC reviewed and quantified. The study showed that 68.8% of patients were in need of IPC (intermittent pneumatic compression) but 29.5% of these patients were either contraindicated or were unable to tolerate IPC, revealing a significant unmet need for an alternative anti-stasis (blood clot prevention) intervention. It is to this cohort the geko™ device was fitted for unmet need.

The study measured VTE events at 90 days post-stroke. The data shows that the patients treated with IPC alone, as the standard of care, 2.4% suffered a VTE event, compared to a 0% incidence of VTE in patients prescribed the geko™ device alone. Patients prescribed the device also showed no adverse events and reported a greater tolerance of the geko™ device compared to IPC. Furthermore, the geko™ device provided an anti-stasis intervention where previously patients would have had no other intervention available to them (drugs following acute stroke are not recommended by NICE in the UK), ensuring no immobile stroke patient, with a high risk if VTE, was without a mechanical VTE prophylactic intervention.


  1. Green S J et al. Covid-19 accelerates endothelial dysfunction and nitric oxide deficiency. Microbes Infect. 2020 May 16 doi: 10.1016/j.micinf.2020.05.006 [Epub ahead of print].
  2. Vagra S et al. Zsuzsanna VEndothelial cell infection and endotheliitis in COVID-19. The Lancet. Volume 395, Issue 10234. P1417-1418, MAY 02, 2020.
  3. Wang J et al. Tissue Plasminogen Activator (tPA) Treatment for COVID‐19 Associated Acute Respiratory Distress Syndrome (ARDS): A Case Series. ISTH Academy. Moore H. 04/08/20; 291588.
  4. Zhang L et al. Deep Vein Thrombosis in Hospitalized Patients with Coronavirus Disease 2019 (COVID-19) in Wuhan, China: Prevalence, Risk Factors, and Outcome. Published in Circulation, ahead of print. 18 May 2020.
  5. Xu et al. Risk assessment of venous thromboembolism and bleeding in COVID-19 patients. Pre-clinical.
  6. Williams J et al. The use of the geko™ device and the activation of the foot and calf pumps for prevention of venous thromboembolism in patients with acute stroke. Data on file Firstkind Ltd 2019.
  7. NICE medical technologies guidance [MTG19] Published date June 20 2014.
  8. FDA clearance. Data on file Firstkind Ltd.
  9. Nicolaides, M Griffin, Measurement of blood flow in the deep veins of the lower limb using the geko™ neuromuscular electro-stimulation device. Journal of International Angiology August 2016-04
  10. Tucker A et al. Augmentation of venous, arterial and microvascular blood supply in the leg by isometric neuromuscular stimulation via the peroneal nerve. The International journal of angiology: official publication of the International College of Angiology, Inc. 2010 Spring;19(1): e31-7.
  11. Lavi S et al. The Impact of Peripheral Nerve Stimulation on Coronary Blood Flow and Endothelial Function. Cardiovasc Drugs Ther (2015) 29:527–533 DOI 10.1007/s10557-015-6628-z
  12. Virchow’s Triad. Virchow triad is a basis for understanding the factors that contribute to thrombosis, including: From: Radiology Secrets Plus (Third Edition), 2011.