This consultation closed on Tuesday 24 November 2015.
The National Health Committee was asked by the health sector to assess two high cost interventions for aortic valve replacement for the treatment of aortic stenosis; these being, Trans-Catheter Aortic Valve Implantation (TAVI) and Sutureless Aortic Valve Replacement.
The NHC held two stakeholder workshops to discuss the model of care for severe AS in 2014 bringing together representatives from Medical Colleges and Societies, District Health Boards and other relevant agencies. Alongside these discussions the NHC undertook health technology assessments of TAVI and Sutureless AVR - synthesising current evidence relating to the NHC's four assessment domains: clinical safety and effectiveness, economic, societal and ethical, and feasibility of adoption.
This work is presented in an NHC Decision Paper for severe aortic stenosis which brings together the learnings of three technical assessments including an overview (Tier 2) assessment of aortic stenosis, a Tier 3 assessment of TAVI and a Tier 3 assessment of sutureless AVR. Each document is linked below.
The NHC has found that there is real potential for leadership and opportunity to improve the model of care for patients with severe AS. Whilst the model of care works well for the majority of patients served by the health system, gaps remain in patient selection processes and the recording of clinical, business, economic, and quality of life outcomes. There also appears to be ongoing pressure to expand access to TAVI into patient groups for which clinical and economic evidence currently supports conventional aortic valve replacement.
A revised model of care for severe aortic stenosis is proposed for implementation including:
Standardised national patient selection criteria for severe aortic stenosis interventions where:
- Conventional surgical aortic valve replacement is the gold standard of care for severe symptomatic aortic stenosis for patients with moderate or low risk, ie patients with acceptable surgical risk (STS score less than 8), and less than two of the following – significant physical frailty, cognitive impairment, or multiple significant comorbidities and no issues related to technical inoperability.
- Only patients with an STS score greater than 8 or those patients identified as technically inoperable (eg with calcific aorta or hostile chest) for surgical aortic valve replacement can be prioritised to receive TAVI.Patients with two or more of the following – significant physical frailty, cognitive impairment or multiple significant comorbidities will not be prioritised for TAVI.
- Sutureless valve replacement is only for high-risk patients based on clinician preference and providing the sutureless valve is a similar price to conventional bioprosthetic valves.
- Patients should receive medical management/palliative care if their life expectancy is less than two years following aortic valve replacement. In the absence of a significant improvement in patient survival (with an acceptable quality of life); medical management should be the preferred option if patients cannot expect to benefit from an improved quality of life following valve replacement. This is broadly consistent with the current New Zealand policy setting for TAVI, where candidates should have a life expectancy greater than two years.
Decision-making should be informed by diagnostic investigations and the following risk management tools to ensure patients receive the most appropriate intervention:
- Operative mortality risk predicted by STS-PROM (the preferred tool based on current evidence) or EuroSCORE II; not EuroSCORE I.
- Frailty score which measures physical frailty and cognitive function.Patients with high frailty indices are unlikely to survive for reasons other than their primary cardiac condition and this can make invasive and expensive interventions like aortic valve replacement clinically futile and cost-ineffective.
- Quality of life measurement from a patient perspective, using a tool where values can be converted to utilities such as EQ5D. For meaningful results data should be captured at referral and year 1 and 2 follow-ups.Quality of life data provides invaluable feedback to clinicians looking to avoid unnecessary and harmful intervention.Anticipated life expectancy of one year or less, or no expectation of improved quality of life, are considered contraindications for aortic valve replacement.
Patient selection to be undertaken by a multidisciplinary team, including appropriate specialist interventional cardiologists, cardiac surgeons, geriatricians and other clinicians.Existing joint cardiac surgery/cardiology conferences to be utilised where possible.
Mandatory entry of clinical and business data into a national registry for interventions for severe aortic stenosis. Fields to include:
- Patient information based on and linked to the national NHI system.
- Surgical risk score (STS-PROM).
- Frailty score which measures physical frailty and cognitive function.
- Quality of life measures from the patient’s perspective using EQ5D, or similar, captured at referral and one and two years post-intervention.
- Technical reasons for inoperability ie calcific aorta, hostile chest.
- Multidisciplinary team treatment decision.
- Treatment undertaken, ie surgical aortic valve replacement, balloon valvuloplasty, transcatheter aortic valve replacement, sutureless aortic valve replacement, medical management or palliative care.
- Valve and delivery system device information to enable tracking.
- Valve Academic Research Consortium-2 (VARC-2) endpoints ie device success, stroke, paravalvular leak, major vascular complications etc.
- Business data including resource utilisation to supplement data collected by DHB patient management and clinical systems to support management of the national AVR waiting list, national AS targets, time to access diagnostics and treatment, and real time budget management.
TAVI will be provided through three cardiac centres: Auckland (for the northern region), Waikato (for the remainder of the North Island) and Canterbury (for the South Island).
The number of TAVI procedures will equate to a level of 10.7 per 100,000 population 65 years or older across New Zealand, a total of at least 70 procedures.
TAVI are currently provided at varying rates across New Zealand. For those DHBs with greater than 10.7 per 100,000, close monitoring is required to ensure the referrals meet the patient criteria and patients are prioritised appropriately for TAVI.
The intervention rate is subject to future revision consequent to significant new evidence indicating a material change in the relative value of TAVI within the model of care.
The multidisciplinary team for each cardiac centre is expected to manage the schedule and workload to ensure that the appropriate number of surgical aortic valve replacements, TAVI and sutureless valve replacements are delivered for each DHB. The volume of patients receiving these interventions each year is expected to align with the national intervention rate targets and elective surgical targets. Patients will need to be prioritised to meet this requirement.