Subclinical Aortic Valve Bioprosthesis Thrombosis Assessed With 4D CT

Subclinical Aortic Valve biOprosthesis thRombosis Assessed With 4D Computed tomographY Imaging

TAVR is an increasingly used technique for the treatment of aortic valve stenosis. However, recent clinical experience has suggested that subclinical aortic valve bioprosthesis thrombosis may occur early after valve replacement. The frequency of this potentially ominous phenomenon on both transcatheter and surgical aortic valve bioprosthesis is unknown, as this condition is difficult to detect.

The recent development of cardiac 4D computed tomography imaging (4DCT) shows great promise for the evaluation of valve leaflet mobility and morphology.

The purpose of this study is in an observational design to assess the frequency of subclinical abnormal leaflet motion and morphology in patients treated with transcatheter or surgical aortic valve bioprosthesis. In addition, the 'natural evolution' of this phenomenon as well as its relation to medical treatment and MACCE will be assessed.

MATERIAL In the period from May 2014 to November 2015, a random subset of patients who underwent transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR) were offered intensified post-procedural clinical and imaging follow-up. It is intended to examine a variety of implanted transcatheter heart valves (THV) as well as surgical aortic valve bioprosthesis.

METHODS:

Post-procedural clinical and imaging follow-up encompasses the following:

• Thoracic 4DCT scanning - with evaluation of leaflet morphology and leaflet motion
• Transthoracic echocardiography - with evaluation of peak aortic valve gradient, mean aortic valve gradient, aortic valve area/effective orifice area (cm2), paravalvular leakage, central aortic valve regurgitation, and left ventricular ejection fraction
• Clinical follow-up: improvement in New York Heart Association (NYHA) class dyspnea, and major adverse cardiac and cerebro-vascular events (MACCE)
• Registration of anti-coagulation/anti-thrombotic therapy following aortic valve replacement

All patients will receive the above-described post-procedural follow-up at two different time-points:

• The first follow-up contact will be planned 30 to 180 days after the TAVR or SAVR procedure. The medical treatment will not be changed based on the generated data.
• The second follow-up contact will be planned 120 to 180 days after the first follow-up contact (see above). This second follow-up offers the possibility to study the 'natural evolution' of this process. In those patients with an abnormal leaflet morphology and/or motion, a treatment with rivaroxaban 20mg daily will be initiated.
• Those patients initiated on rivaroxaban after the second follow-up will be called in for a third clinical and imaging follow-up, with focus on leaflet morphology and/or motion after rivaroxaban therapy. In case of persistent abnormal leaflet morphology and/or motion despite NOAC, a treatment with Marevan (INR 2-3) will be initiated.
• Those patients initiated on Marevan after the third follow-up will be called in for a fourth clinical and imaging follow-up contact.

Inclusion Criteria:

Successful TAVR or SAVR performed at Rigshospitalet, Copenhagen, Denmark

Exclusion Criteria:

• renal dysfunction (eGFR <25 ml/min)
• TAVR-in-TAVR
• Patients living in Greenland or the Faroe Islands