Tsunami: latest of 10 VTE prophylaxis guidelines launched at ASH

New American Society Hematology (ASH) guidelines on the prevention of VTE in surgical patients are the latest to be published in a planned suite of 10 VTE management guidelines.

The tsunami of VTE guidelines from ASH – six last year, one this year and three more due in 2020 – is in the context of several new drugs coming on the market in recent years, many more in the pipeline and a challenging lack of high quality evidence.

Lead author on the new document Dr David Anderson, from Canada’s Dalhousie University, told ASH 2019 that the guidelines addressed 30 questions pertaining to VTE prophylaxis in major surgical procedures or major trauma requiring hospitalisation. 

He said the panel focused on clinically important symptomatic outcomes – mortality, symptomatic PE, symptomatic proximal DVT and major bleeding – with less emphasis on asymptomatic DVT detected by screening tests. 

Some of the highlighted recommendations were:

  • For patients experiencing a major trauma who are deemed to be at high risk for bleeding, pharmacological prophylaxis is not recommended by the panel. 

“We recommend however that this risk of bleeding must be reevaluated over the course of recovery of patients as this may change the decision around the intervention over time,” Dr Anderson said.

He used the example of a major trauma patient whose risk of bleeding would change from high to low-moderate over the course of a week and in whom the use of pharmacologic prophylaxis would then be recommended. 

  • In patients undergoing major surgical procedures and not receiving pharmacological prophylaxis, there is a recommendation for mechanical prophylaxis in patients.

“ …and for those patients we recommend the use of intermittent compression devices over graduated compression stockings,”  said Dr Anderson. 

  • The ASH panel recommends against prophylactic IVC filters.

“Although IVC filters do result in a small reduction in the risk of symptomatic PE, this is outweighed by the increased risk of DVT with the insertion of these devices.”

  • For patients undergoing major surgery who receive pharmacological prophylaxis, the panel suggests also combining prophylaxis with mechanical methods rather than pharmacological agents alone. 

The recommendation particularly pertains to patients at high or very high risk of VTE, he said.

  • For patients undergoing major surgery, LMWH or unfractionated heparin are both considered reasonable choices for pharmacological prophylaxis, with no significant difference between the two agents.
  • For patients undergoing major surgery, extended antithrombotic prophylaxis (3 weeks or more) is favoured over short term prophylaxis (up to 2 weeks).

Regarding specific surgical procedures, the panel recommends pharmacological prophylaxis in total knee and hip arthroplasty, hip fracture repair, major general surgery and major gynaecological procedures. 

Dr Anderson said most of the evidence on VTE prevention was extrapolated from the setting of total hip and knee arthroplasty. 

One of the recommendations the panel struggled with the most was regarding the use of anticoagulant prophylaxis for neurosurgery, due to conflicting evidence.

“Because of the concern about bleeding we made the decision not to recommend them [anticoagulants] – but that is a conditional recommendation and we do recognise there is room for judgment based on the bleeding and VTE risk of the individual patient.”

The guidelines, published in Blood Advances this month, do not recommend routine use of pharmacological prophylaxis for patients undergoing total prostatectomy, TURP, or laparoscopic cholecystectomy due to the very low baseline risk of VTE. 

Dr Anderson reiterated the need for studies that focus on clinically important outcomes, the baseline risk of VTE in the modern surgical setting, evaluations of prophylaxis strategies, VTE risk in outpatient procedures, and in procedures other than arthroplasty.

New ASH guidelines on the treatment of VTE, cancer-associated VTE and thrombophilia are due in 2020.

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