This single centre retrospective analysis of Trifecta valve utilisation demonstrates post-operative complication rates in line with other series(9, 16, 17). The incidence of aortic valve reoperation due to structural valve degeneration was low, with only a single patient requiring repeat aortic valve replacement at 3 years post-surgery for transvalvular leak due to a non-calcific leaflet tear. This was a 34-year-old man who had a previous AVR 10 years earlier with another BHV and wanted to avoid anticoagulation due to his lifestyle preferred to have another BHV. There are a range of BHVs available, but it can be either stented or stentless. Stentless BHVs were developed in an attempt to minimise the transvalvular gradient and improve the effective orifice area(11, 17). However, recent studies have suggested that stentless porcine valves have reduced durability(11) and an increased rate of SVD requiring re-intervention(18). Most BHVs used in contemporary practice are now stented and various bovine pericardial valve prosthesis have demonstrated initially better long-term durability and excellent haemodynamic performance(19). However, few studies have demonstrated that there is a high chance of SVD on trifecta(10, 12, 16) and pericardial mitral flow(19, 20) aortic prosthetic valve post-surgery.
The Trifecta valve is a stented pericardial bovine heart valve designed for supra-annular placement. It was first introduced for patient use in 2007. The valve leaflets are externally mounted on the stent which allows cylindrical opening during systolic contraction to provide an enhanced effective valve orifice area and optimised transvalvular gradients. Several literature reports identified that first-generation Trifecta aortic valve was at risk of cusp tears or leaflet calcification(21–24). The latest generation Trifecta GT valve was introduced in 2016 to provide added handling protection for the stent and leaflets (14). Modifications included a streamlined and enhanced holder, a softer sewing ring, an additional titanium band in the stent base, optimised leaflet suturing techniques and collagen alignment.
The rate of SVD in our study is lower than other previously published studies that have demonstrated a 1% incidence of repeat operation with Trifecta valve for SVD at 5 years(10), and 3.3% at 7 years(16). Studies have also reported that younger patients have a higher incidence of SVD (3 years: 2.4%, 5 years: 4.2% and at 7 years: 27.9%)(22). This was the case in our study with our single patient who is 34 years old, exhibiting SVD. Previous studies of the trifecta valve have reported the incidence of device related stroke, systemic embolism of 2.7–6.0%(12). In our cohort we observed a post-operative stroke rate of 0.8% in a patient who underwent combined AVR + CABG with no systemic embolic complications.
Valve performance in our cohort was good and in 3 year follow up data, there was no patient who exhibited severe paravalvular regurgitation and only one patient who had developed a moderate paravalvular regurgitation. The survival rate at hospital discharge was 96.7%, at 30 days was 97.2%, at 1 year 94.1% and at 3 years was 79.6%. Irrespective of having an older population in our cohort of patients, the survival rate was better than other studies who had survival rates ranging from 70–88.7% (11, 14, 16). The incidence of a mild paravalvular leak at one year was 2.6% (n = 287 patients at risk) and minimal transvalvular leak was 21.7%. Haemodynamic performance was very favourable in the case series with mean valve gradients at one year of 9.5 ± 4.1 mmHg compared to ranges from 10.1 to 20mmHg in the published literature (10, 11, 14).
Our experience demonstrates that the use of the Trifecta valve is safe and achieves good clinical outcomes. However, like any bioprosthetic valve it has its own advantages and disadvantages. In our experience avoiding over-sizing of the valve, careful knot tying and valve handling to avoid inadvertent damage to the leaflets are the key elements to achieving good results. We suggest that unnecessary handling of leaflets at the time of the implant may be a significant contributing factor to the early structural valve deterioration that has been reported in other studies(16, 22). We believe that proctoring and adequate training when a surgeon first uses the valve are vital to ensuring good results. We will also urge surgeons new to the use of this valve to exercise caution if they implant the valve with the Cor-Knot® system to avoid deploying the Cor-Knot® in such a way that it may be in contact with the valve leaflet and initiate SVD. In our practice, we try to avoid using Cor-knot especially if we are implanting the Trifecta valve.
There are a number of limitations of this study. Firstly, it is a retrospective analysis of prospectively collected data with a small sample size from a single centre and as such the generalisability of these results to other centres is unknown. A further limitation is that echocardiographic follow-up was not available for all patients at either one or three year. This is due to the retrospective nature of the study and variations in regional surveillance programmes. 1-year echocardiographic data was available for two thirds of the original cohort and as such the results at this time are likely to be robust. However, 3-year follow-up echocardiographic information was only available for 13.5% of the original cohort. Despite this however it is encouraging that there has been no significant change in the gradients across the valves in these patients. Development of mild transvalvular regurgitation in around one quarter of patients between one and three years is potentially concerning, and these patients should continue to be followed up on a long-term basis. It should be noted that this study includes data from two versions of the Trifecta valve. Although the Trifecta GT contains a number of modifications the fundamental design of the valve is the same and as such no comparisons have been made between the two valve types. Another limitation is that this study represents a heterogeneous group of procedures. Although the key message regarding the safety profile of the Trifecta valve is not affected by this issue, it does mean that direct comparisons of the results from this study with other more homogenous groups should be undertaken with caution.
Long-term multicentre data is required to ensure the on-going safety issues of any implantable medical device. Unfortunately, the UK Heart Valve Registry was defunded and as such prospective and retrospective systematic monitoring of heart valve performance is not currently possible in UK. Ideally, as is the case with other devices such as hip replacements, prospective national registries with serial echocardiographic data for all biological valves implanted should be established and would provide an invaluable resource. Establishing such registries to facilitate long-term performance monitoring is now even more important given the rapid expansion in utilisation of transcatheter aortic valve implantation.