Sutureless AVR is a relatively new procedure which employs a bioprosthetic (‘tissue’) valve requiring no (or very few) sutures to stay in place. Sutureless valves stay in place using either a self-expanding or balloon-expandable frame. By removing the need for sutures, operative and cardiopulmonary bypass times may be reduced compared with conventional AVR. Reduced operative time is particularly advantageous for patients requiring multiple procedures including concomitant coronary artery grafting for the treatment of ischaemic heart disease. Sutureless AVR may be undertaken using conventional open heart surgery or minimally invasive techniques. In New Zealand, about 80 sutureless AVR procedures have been undertaken since 2011, all of which have used open heart surgery. Sutureless valves have now been approved for use in Australia and Europe, but not yet in the United States outside clinical trials.
The NHC prepared a brief Technology Note on sutureless AVR in May 2012, in response to a request from Waikato District Health Board that year to assess the technology. At the time, it was concluded that insufficient evidence was available for a full assessment to be made, and that sutureless AVR should be conducted only under clinical trial conditions. In March 2013, representatives from ANZSCTS and the Waikato Cardiothoracic and Vascular Surgery Unit, requested that the NHC carry out further assessment of sutureless AVR. It was decided that further assessment of sutureless AVR would be appropriate, given that in the time since the previous NHC report, additional clinical data had been published, NICE (National Institute for Health and Care Excellence) had issued guidance and HealthPACT had assessed the procedure.
Clinical safety and effectiveness
The current evidence base is limited for sutureless AVR. Randomised controlled trials with short follow-up time suggest that sutureless AVR is safe, with low incidence of complications and comparable mortality compared with conventional surgical AVR. This is supported by non-randomised controlled trials. Compared with TAVI, sutureless AVR may have lower rates of paravalvular leak. Evidence is limited to observational studies, but sutureless AVR appears to have similar short-term survival compared with surgical AVR in moderate to high-risk patients.
Economic
Current evidence suggests sutureless AVR may have similar cost-effectiveness to conventional surgical AVR, with sutureless AVR having comparable outcomes and the possibility of lower costs. The NZ data available from 2012/13, though limited to just 12 sutureless AVR records, show a modest cost differential of $2,000 with similar length of stay compared with conventional bioprosthetic surgical AVR (Table 2). The price differential between sutureless valves and conventional bioprosthetic valves is small and declining. There is currently no evidence of additional procedural or downstream costs associated with sutureless AVR compared with conventional surgical AVR, but there is some evidence of potential savings from reduced hospital and ICU length of stay. Sutureless AVR is a substitute procedure for conventional surgical AVR in high-risk patients; as such it is not expected to significantly expand the population pool receiving surgical AVR.
Table 2: Cost of sutureless AVR compared with conventional bioprosthetic AVR
Sutureless AVR
All bioprosthetic valves
Average cost
$48,000
$46,000
Average length of stay (days)
13
12
Valve cost
$6,500
$5,700
Number of records
12
331
Source: NHC analysis of NCCP data accessed in 2015, using cost schedule seven.
Sutureless valves have declined significantly in price over the past four years as a result of competition. When the NHC first assessed sutureless AVR in 2012, the valve was nearly twice the price it is today. A sutureless valve purchased by Auckland DHB is now roughly the same cost as a regular tissue valve purchased by Canterbury DHB. However, whilst the Sorin Perceval S valve and Medtronic 3f Enable model 6000 valve have become price competitive, the Edwards Lifesciences Intuity valve is reportedly about twice the price of its competitors; with no head-to-head trials available to justify the premium. (32)
Medtronic announced its intention to discontinue production of the Medtronic 3f Enable valve in May 2015. There remains variation in price of sutureless valves across the country, which indicates there could be savings. The savings could be obtained from all the DHBs receiving the lowest cost; the lowest costs could be obtained through DHB sharing pricing information or from national collective purchasing.
Given that the safety and efficacy of sutureless AVR seems comparable, varying access to sutureless valves does not give cause for concern. However, this view may change as the evidence for sutureless AVR evolves.
Feasibility of adoption
There may be between five and ten percent of AVR patients that could benefit from sutureless AVR. Potential beneficiaries of the procedure include patients with anatomical features that make suturing difficult or risky, such as a heavily calcified aortic annulus or a very small aortic root. There are no workforce or infrastructure considerations identified that would impede the increase use of sutureless AVR; although, like with all new treatments, appropriate training and oversight would need to be put in place if the use of sutureless AVR increased. Similarly the impact on theatre and staff scheduling and bed days required for sutureless AVR compared with surgical AVR would need to be factored into production planning.
