EACTS 2023: On-X aortic valve “remains safe and effective with low dose warfarin”

Aung Oo presents the data at EACTS 2023

Data from the On-X aortic heart valve low INR post-market study, presented during a late-breaking science session at the 2023 European Association for Cardio-Thoracic Surgery (EACTS) annual meeting (4–7 October, Vienna, Austria), confirm that the device remains safe and effective with low-dose warfarin.

The On-X aortic low INR post-market study is a prospective, international, multicentre, observational study to assess the occurrence of bleeding, valve-related thromboembolism and valve thrombosis with the On-X Aortic (Artivion) prosthetic valve when targeted at an international normalised ratio (INR), level of 1.8 (1.5‒2 range) during a five-year follow-up period.

The trial is designed to compare adverse event rates for patients with target INR range of 1.5 to 2 per On-X instructions for use, to rates from the previous IDE trial. The trial consisted of 510 participants who have only an On-X aortic prosthetic heart valve implant. The combined primary efficacy and safety endpoints determine the impact of the On-X Aortic prosthetic valve on reducing thrombotic events, major bleeding events, and mortality.

Aung Oo, clinical lead for Aortovascular Surgery at Barts Heart Centre (London, UK) presented real world experience of 510 On-X aortic valve replacement patients treated with low dose warfarin. This included at least one-year and up to five years of clinical data on study participants, with median follow-up time of 3.4 years.

The results show a significantly lower composite primary endpoint of thromboembolism, valve thrombosis, and major bleeding (linearised occurrence rate (LOR) of 2.31% compared to the pre-defined historic control rate of 5.39%, p<0.0001), driven by an 85% reduction in major bleeding and a 73% reduction in all bleeding. Notably, the data reflected an improvement in outcomes compared to the On-X aortic low INR investigational device exemption (IDE) study data first published in 2014.

Oo said: “Heart valve replacement therapy presents several postoperative challenges for patients, especially the need for blood thinners and the related risk of bleeding and thrombotic events. These long-term data demonstrate the clinical benefits of a lower-dose post-operative warfarin regimen, further validating the use-case for On-X valves with low-dose warfarin.”

“The data presented by Professor Oo validate the safety and benefit of physicians managing On-X aortic valve patients at a lower INR compared to other mechanical valves and reinforce our conviction in On-X as a key component of our product portfolio,” said Pat Mackin, chairman, president, and chief executive officer of Artivion. “With these data, we are increasingly confident in our ability to gain further market share globally with On-X, the only mechanical aortic heart valve that can be maintained at an INR of 1.5 to 2 backed by that recommendation in the American College of Cardiology/American Heart Association Guideline for the Management of Patients With Valvular Heart Disease.”


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