The Nordic Aortic Valve Intervention Trial

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is a new and rapidly evolving treatment option for patients with severe degenerative aortic valve stenosis. Short- and mid-term results with transcatheter valve prostheses are promising in high-risk surgical patients, but long-term results are lacking. TAVI could potentially be an attractive minimally invasive treatment also for patients with moderate and low surgical risk, but no comparison has been made with the standard surgical treatment for aortic valve stenosis.

AIM: To compare TAVI and surgical aortic valve replacement (SAVR) in patients with severe aortic valve stenosis.

POPULATION: All patients with severe degenerative aortic valve stenosis referred for elective or subacute aortic valve intervention will be screened for study eligibility. To be included subjects must be 70 years or older, anatomical and technical eligible for both interventions, expected to survive more than 1 year after the intervention, and able to provide written informed consent. Study exclusion criteria include isolated aortic valve regurgitation or other significant valve disease, coronary artery disease requiring revascularisation at the time of referral, previous open heart surgery, a myocardial infarction or percutaneous coronary intervention within the last year, a cerebral infarction within the previous 30 days, severe renal -, pulmonary -, or infectious disease, and unstable preoperative condition.

DESIGN: The project is a national multicenter randomized clinical trial. Patients fulfilling all inclusion- and no exclusion criteria will be randomized to either TAVI or SAVR. Randomization will be 1:1 with 140 subjects in each group and stratified according to centre, age (70-74 years vs 75 and older), and coronary co-morbidity not requiring revascularisation (yes vs no). Primary outcome will be assessed by a blinded adjudication committee. Patients screened but not included in the study will be followed yearly. Screening and inclusion will commence in December 2009. Inclusion is expected to last 2 to 3 years, and subjects will be followed for 10 years.

INTERVENTIONS: Subjects randomized to TAVI will undergo percutaneous retrograde trans-femoral or trans-subclavian aortic valve implantation with the Medtronic CoreValve(TM) self-expandable bio-prosthesis. Before implantation a balloon dilatation of the aortic annulus will be performed. Subjects randomized to SAVR will undergo conventional surgical aortic valve replacement with a bio-prosthesis on cardiopulmonary bypass in normothermia with cold cardioplegia cardiac arrest. All interventions will be performed under general anaesthesia, and post-interventional medical and anticoagulation treatment will be uniform.

END POINTS: The primary end point is a combined outcome measure consisting of death from any cause, myocardial infarction, and stroke one year after the intervention. Secondary end points are death from any cause, cardiac death, cardiac -, cerebral -, pulmonary -, and renal complications, prosthesis re-intervention, procedure success and - time, admission lengths, functional class, quality of life, prosthesis and left ventricular structure and function. Follow-up visits will be performed after 30 days, 3, 6 and 12 months, and yearly thereafter for a minimum of 10 years.

Inclusion criteria

• Patients must have severe degenerative aortic valve stenosis (echocardiographic criteria: AV effective orifice area (EOA) of < 1 cm2, mean AV gradient of > 40 mmHg, or AV peak systolic velocity of > 4.0 m/s)
• Patients must be symptomatic from the aortic valve stenosis (dyspnoea in NYHA-class II or greater, angina pectoris, or syncope), or asymptomatic but with echocardiographic evidence of left ventricular hypertrophy, decreased left ventricular ejection fraction, or atrial fibrillation)
• Patients must be 70 years or older
• Patients must be technical and anatomical eligible for both interventions (as specified by Medtronic CoreValve(TM) for the TAVI procedure) after a formal consult by a cardiologist and a cardiovascular surgeon
• Patients must be expected to survive more than one year after the intervention
• Patients must be able to provide written informed consent as approved by the regional ethical committee after having received adequate information about the study
• Patients must be able and agree to return to all post-procedural follow-up visits

Exclusion criteria

• Isolated aortic valve insufficiency
• Other significant heart valve disease requiring intervention
• Coronary artery co-morbidity requiring revascularisation
• Any previous open heart surgery
• Myocardial infarction or percutaneous coronary intervention within the last year
• Stroke or TIA within the last 30 days
• Renal insufficiency requiring hemodialysis
• Pulmonary insufficiency (FEV1 or diffusion capacity < 40% of expected)
• Active infectious disease requiring antibiotics
• Emergency intervention (within 24 hours after the indication for intervention has been made)
• Unstable pre-interventional condition requiring inotropic support or mechanical heart assistance
• A known hypersensitivity or contraindication to heparin or nitinol
• Currently participating in an investigational drug or another device study