Aortic Stenosis Decision Paper

Aortic Stenosis
Decision Paper

National Health Committee (NHC) The National Health Committee (NHC) is an independent statutory body charged with prioritising new and existing health technologies and making recommendations to the Minister of Health. It was re-formed in 2011 to establish evaluation systems that would provide the New Zealand people and the health sector with greater value for money invested in health. The NHC executive is the secretariat that supports the committee. The NHC executive’s primary objective is to provide the committee with sufficient information for it to make decisions regarding prioritisation and reprioritisation of interventions and services. They do this through a range of evidence-based products chosen according to the nature of the decision required and timeframe within which decisions need to be made. The New Zealand Government has asked that all new diagnostic and treatment (non-pharmaceutical) services, and significant expansions of existing services, are to be referred to the NHC. In August 2011 the NHC was appointed with new terms of reference and a mandate to establish the capacity to assess new and existing health technologies. Its objectives (under Section 4.2 of its terms of reference – www.nhc.health.govt.nz) include contributing to improved value for money and fiscal sustainability in the health and disability sector by: providing timely advice and recommendations about relative cost-effectiveness based on the best available evidence; providing advice and recommendations which influence the behaviour of decision-makers, including clinicians and other health professionals; providing advice and recommendations which are reflected in resource allocation at national, regional and local levels; and contributing to tangible reductions in the use of ineffective interventions and improved targeting to those most likely to benefit. In order to achieve its objectives under Section 4.2 and to achieve ‘value for money’, the NHC has adopted a framework of four assessment domains – clinical safety and effectiveness; economic; societal and ethical; and feasibility of adoption – in order that assessments cover the range of potential considerations and that the recommendations made are reasonable. It is intended that the research questions asked will fall across these domains to ensure that when the committee comes to apply its decision-making criteria, it has a balanced range of information available to it. When the NHC is setting those questions, they will have the decision-making criteria in mind. The 11 decision-making criteria will assist in the determination of the NHC work programme and in the appraisal and prioritisation of assessments.

Executive summary

1. 
   The suite of severe aortic stenosis assessment documents is part of the extensive cardiovascular programme being undertaken by the National Health Committee. These assessment documents are now at the stage where they can be considered by the committee for sharing with the sector as part of a formal consultation process.
   
2. 
   The Tier 2 aortic stenosis assessment identifies transcatheter aortic valve implantation (TAVI) and sutureless aortic valve replacement (sutureless AVR) for further assessment to ensure their appropriate use, given limited public funding and cardiothoracic surgical service capacity and capability.
   
3. 
   Conventional surgical aortic valve replacement remains the gold standard treatment for at least 80% of patients requiring aortic valve replacement. Internationally, sutureless aortic valve replacement and TAVI have been indicated in high-risk patients, comprising about 5% of patients, or no more than 30 patients per annum. TAVI has also been indicated for inoperable patients, comprising a much larger potential patient pool. But for most inoperable patients, medical management or palliative care remain the standard of care.
   
4. 
   The Tier 3 sutureless aortic valve replacement assessment found available evidence suggesting sutureless AVR is a safe and effective alternative to conventional surgical AVR in high-risk patients. Although limited economic data is available, the procedure may be cost-effective using the Sorin valve, which has reduced significantly in price since the NHC began its assessment of the procedure. There may also be future potential, not yet proven, in relation to reduced length of stay and facilitating minimally invasive cardiac surgery, which could result in productivity and efficiency gains for district health boards (DHBs).
   
5. 
   The Tier 3 transcatheter aortic valve implantation assessment found that neither the clinical nor the economic evidence suggested a significant expansion in TAVI volumes. The proposed target population with severe aortic stenosis for TAVI is recommended to be limited to those patients with high surgical risk (STS score >8) or those patients identified as technically inoperable (eg with calcific aorta or hostile chest) for surgical AVR. Any expansion into the technically inoperable patient population should come from within current service volumes. Though no expansion in volumes beyond population growth is suggested, reprioritisation of TAVI towards high-risk and technically inoperable patients would modestly increase overall aortic valve replacement volumes. The expected national cost impact would be $1 million, increasing to $1.7 million over five years.
   
6. 
   For patient safety, it is imperative that TAVI is undertaken in centres with sufficient volume and experience. As volumes are not expected to expand significantly in the foreseeable future, TAVI centres should be limited to the current three centres: Auckland, Waikato and Canterbury.
   
7. 
   The recommendation is for sutureless AVR and TAVI to be ‘absorbed’ within the current cardiac surgical services budget and resources. These interventions are a further example of general expansion of cardiac services on a procedure-by-procedure basis. This type of incremental approach to new technologies is unsustainable and there is a real need to establish a strategic plan for cardiac services in NZ that sets a five to ten-year view of where the services should be.
   
8. 
   The vast majority of severe aortic stenosis patients fall into the business as usual surgical AVR pathway. The potential health and independence gains from investing in new technologies for high-risk aortic stenosis are at this time relatively small.
   
9. 
   The assessments of AS, sutureless AVR, and TAVI have identified some patient and sector value in the use of the sutureless AVR and TAVI, but there may be more value from implementing improvements to the overall model of care for severe AS.
   
10. 
    While draft recommendations, contained below, indicates opportunities for improvements in the model of care, it is important to emphasise that the current model of care works reasonably well for most patients with severe AS.
    
11. 
    A draft revised model of care, worked up in collaboration with key stakeholders, proposes a process to identify patients unlikely to survive for reasons other than their primary cardiac condition, which would make aortic valve replacement clinically futile and cost-ineffective. The revised model of care incorporates:
    

• 
  a standardised national patient selection criteria for severe aortic stenosis interventions.
  
• 
  an operative risk tool, preferably STS-PROM rather than EuroSCORE I.
  
• 
  a frailty and cognitive assessment as part of the clinical decision process.
  
• 
  patient selection to be undertaken by a specified multidisciplinary team, including a geriatrician.
  
• 
  mandatory entry of clinical and business data into a national registry for interventions for severe aortic stenosis.
  
• 
  quality of life measurement from a patient perspective, using a tool such as EQ5D, captured at referral and year 1 and 2 follow-ups.
  

12. 
    Input from key stakeholders is required on the proposed draft recommendations. This is required to fully understand the implications of the proposed advice and the associated system costs of the non-procedure related aspects of the revised model of care. These costs will include the costs of the national registry, change to surgical risk tool, implementation of frailty tool, potential additional two-year follow-ups, quality of life measurement tool, data collection, entry and reporting, and any further costs associated with the multidisciplinary team, eg costs of geriatrician time.