Call to review ‘ineffective’ VTE prophylaxis guidelines


By Geir O'Rourke

21 Mar 2024

Compliance with venous thromboembolism guidelines during orthopaedic procedures is not reducing the risk of VTE in patients undergoing total hip and knee arthroplasty, an Australian study has concluded.

The results suggest the guidance is ‘not effective’ and should prompt a rigorous review of the Australian Orthopaedic Association VTE prevention guideline, which differs from the most recent NHMRC guidance, according to the researchers.

Conducted across 19 high-volume hospitals around Australia, the study included 1838 participants who were each followed for a year post-surgery.

Symptomatic VTE was experienced up to 90-days post-surgery by 48 patients (2.6%), while 17 had bleeding complications requiring readmission or reoperation.

But importantly, those patients who had received prophylaxis in line with the AOA’s guidelines were at the same or higher risk of 90-day VTE after arthroplasty compared with those who had not, the researchers reported in Nature Scientific Reports (link here).

“These findings are consistent with the US Surgical Care Improvement Project (SCIP), which reported a higher rate of PE in those who received care compliant with the VTE process measures (doctor ordered VTE prophylaxis, and the patient received VTE prophylaxis at the right time),” they wrote.

“This program uses process of care elements that are also very broad and may mask any differential outcome associated with different types of chemoprophylaxis.”

Results were also consistent with patients with high bleeding risk were excluded from the analysis, according to the team.

The authors noted that compliance with AOA recommended VTE prophylaxis was “flexible” and surgeons were given discretion to use aspirin (100–300 mg), low molecular weight heparins or DOACs for people at routine VTE risk, although in this study aspirin was also used for people assessed as high VTE risk.

As a result, adherence with the AOA’s advice was somewhat patchy, with 20% non-compliant with all guideline recommendations, 14% for risk-stratified prophylaxis, 36% for duration and 68% for other general recommendations.

Beyond that, the authors said they were concerned at the lack of data regarding the methodological quality and evidence underpinning the AOA guidelines, in contrast to the “high quality” and “rigorous” NHMRC document from 2009 (but now rescinded).

The key difference between the two guidelines was that the NHMRC guidelines recommended only potent anticoagulants as all THA and TKA recipients are considered at high risk of VTE, whereas the AOA guidelines provides criteria to stratify patient risk, and recommends either potent anticoagulants or aspirin (an antiplatelet agent) with a sequential compression device for people assessed as being at routine VTE risk.

But there were serious question marks over this more flexible approach, the authors concluded.

“The aim of clinical guidelines is to help clinicians apply evidence from clinical trials into real-world practice and improve patient outcomes,” they wrote.

“In contrast to this aim, we found non-compliance with AOA VTE prevention clinical guidelines was not associated with the risk of symptomatic 90-day VTE after THA/TKA, suggesting that these guidelines are not effective at reducing VTE events.”

“Definitive studies are needed to validate individualised VTE risk assessments and confirm effective personalised VTE prophylaxis strategies, particularly for those considered high risk, to improve patient outcomes and the value of arthroplasty surgery.”


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