Sutureless valves—are we there yet? Evidence from the PERSIST-AVR trial

Abstract

Sutur eless valves have emerged as another option for implantation of a biological valve. Several benefits of sutureless valves have been reported in the literature. However, concerns have been raised over increased incidence of para-valvular leak and need for permanent pacemaker implantation. Most of the evidence has been obtained from observational and retrospective single institutional series. The Perceval Sutureless Implant Versus Standard-Aortic Valve Replacement (PERSIST-AVR) trial is the first multicentric randomized control trial to compare sutureless valves with standard bio-prosthesis. Evidence from this trial has been critically analyzed in this review.

Sutureless and rapid deployment valves represent an intermediate option between transcatheter aortic valve replacement (TAVR) and conventional surgical aortic valve replacement (SAVR) in patients requiring a bio-prosthetic aortic valve replacement (AVR). These valves also facilitate implantation using minimal access techniques. While there have been several studies reporting comparing sutureless with standard stented biological valves, there has been a lack of randomized studies and the Perceval Sutureless Implant Versus Standard-Aortic Valve Replacement (PERSIST-AVR) trial fills that lacuna [1].

At the very outset, it is important to differentiate between the “Sutureless” and “Rapid deployment valves” as they are often used interchangeably in the literature. “Sutureless” valves (Perceval, Sorin) have a collapsible design and require no sutures for deployment. Rapid deployment valves (Edwards Intuity) on the other hand require three sutures in addition to a balloon-inflatable stent. These are the only two valves available in this category at present, as the other rapid deployment valve ATS 3f Enable Bioprosthesis has been withdrawn [2].

The PERSIST-AVR trial compared “Sutureless” valves with conventional stented valves. The type of stented valve was left to the discretion of individual surgeons. This was a multi-center adaptive randomized controlled trial where patients were randomized to sutureless or stented valve implantation. Adaptive randomization is a concept where the randomization adapts to the evidence gathered by changing the allocation and is used to minimize the imbalance between treatment groups [3]. The study was carried out across 47 centres in 12 countries. Patients with severe symptomatic aortic valve stenosis were included after computed tomography scan, and after assessing suitability for the proposed surgical access as well as need for concomitant procedures. The need for aortic root enlargement precludes implantation of sutureless valves and was an important exclusion criterion. Both midline sternotomy and mini-sternotomy were allowed, but procedures done through right anterior mini-thoracotomy were not included due to concerns over expertise variability. Follow-up has been planned to continue for 5 years; however, currently, the authors have provided the 1-year outcomes. This was a non-inferiority trial where the primary outcome of the study was freedom from major adverse cerebral and cardiovascular events (MACCE) and defined as a composite of all-cause death, myocardial infarction, stroke, or valve reintervention at 1 year.

In total, 453 patients were randomized to the sutureless group and 457 patients to the stented group. Of the 910 patients randomized, only 819 (90%) received the valve they were randomized to (per-protocol), with 407 receiving the sutureless valve and 412 the stented valve. Concomitant coronary artery bypass graft (CABG) was performed in 24.3% and 22.3% of patients in the sutureless and stented groups respectively and the number of patients requiring septal myomectomy was also similar at 3.4% and 3.2% in the two groups.

MACCE rates were 8.1% in the sutureless group and 7.8% in the stented group. The individual components of the MACCE were also similar across the 2 groups. Freedom from the MACCE rates, the primary outcome, was seen in 91.6% in the sutureless group and 92.0% in the stented group. The rate of para-valvular and central leak was low in both the arms, with no differences observed between the groups at the time of discharge or 1-year follow-up. The mean aortic pressure gradient at 1 year was identical in both groups at 12.6 mmHg. New York Heart Association (NYHA) class distribution at all time points was also similar. Structural valve degeneration and valve thrombosis were reported in 1 patient each in the sutureless valve group only. Endocarditis was seen in 1.5% of the sutureless valves and 1.9% of the stented valves. Sutureless valves were thus found to be non-inferior to standard stented valves, but did not meet the superiority criteria.

The main strength of the study lies in the fact that this was the first time such a comparison was being made in a randomized setting involving multiple centres. The study also had an adequately powered sample size. The important limitations of the study include a highly selective process of assessment prior to randomization. Besides, a high cross-over rate of 6.5% and non-inclusion of “need for permanent pacemaker implantation (PPI)” in the MACCE composite may have allowed the comparison to be tilted in favour of sutureless valves.

The benefits of sutureless valve

Perceval valves were associated with reduced cardiopulmonary bypass (CPB) and aortic cross-clamp times. Even though these differences were statistically highly significant (p < 0.001) in real terms, the mean difference was roughly only 17 min in each category. This difference in CPB and cross-clamp time also did not result in a clinically measurable difference to the in-hospital outcomes or at 1 year follow-up.

The absence of the sewing ring with sutureless valves is thought to result in better haemodynamics, even in small aortic roots, thereby reducing patient prosthesis mismatch. A meta-analysis comparing sutureless valves with standard bio-prosthesis showed a significantly lower transvalvular gradient in the Perceval valves [4]. Evidence also exists regarding the Perceval aortic valves providing a better effective orifice area in elderly patients with a small aortic annulus [5]. However, in the PERSIST-AVR trial, the mean transvalvular gradients at one-year were identical in both the valve types. Some of the previously reported benefits with sutureless valves, like the reduced need for blood transfusion and shorter intensive care and hospital stay, were not reported in the PERSIST-AVR trial [6].

Issues with sutureless valves

The main issue with the sutureless valves was the significantly higher rate of PPI. At 30 days, the rate of PPI in sutureless valves was 43 (10.6%) compared to 13 (3.2%) among standard valves and the same trend continued at 1 year, where it was 45 (11.1%) versus 15 (3.6%). The sutureless valves have been reported to have a higher rate of PPI compared with both conventional [4] and rapid deployment valves [7]. However, it has to be stressed that most of the PPI were required in the XL valve sizes (27 mm), which were implanted in nearly one in 4 patients in the sutureless valve group.

The other concern previously reported with sutureless valves has been the increased incidence of paravalvular leaks [8]. The concerns over para-valvular leaks were however not corroborated by the PERSIST-AVR trial [1].

Sutureless valves are often preferred in minimal access surgery, especially the right anterior thoracotomy approach, and are considered to be an alternative to TAVR. The sutureless valves, in comparison with TAVR, are associated with lower incidence of perioperative complications and better survival at short-term and mid-term [9]. While the difference in CPB and cross-clamp time did not lead to clinical improvement, it has to be appreciated that the patients included in the study were generally low-risk patients. It is likely that in high-risk patients with multiple comorbidities, reduction in CPB and cross-clamp timings may be beneficial. However, for sutureless valves to be a realistic option, they have to match the standard stented valve outcomes, not only in terms of perioperative complications and mortality, but also long-term durability. The rates of PPI remain a major concern and changes in valve design are perhaps essential to minimize this.

While statistically the sutureless valves may have been shown in the study to be non-inferior to the standard stented aortic valves, clinical equivalence is yet to be established. The PERSIST-AVR trial has a planned 5-year follow-up and it is expected that mid-term outcomes would be available in the future. Modifications of the sutureless valve are inevitable and further studies with newer models and larger sample sizes would perhaps be required for a definitive answer.

Funding

None.

Declarations

Ethical approval and informed consent

Not required as this is a review article.

Conflict of interest

The author declares no competing interests.