Aortic valve stenosis: treatment options

The Perceval bioprosthesis combines the advantages of stentless valves, in terms of haemodynamic performance, with those of a simple implantation technique using a minimally invasive approach

Giuseppe Santarpino MD PhD

Theodor Fischlein MD PhD

Department of Cardiac Surgery, Cardiovascular Center Klinikum Nürnberg, Paracelsus Medical University, Nuremberg, Germany

The aortic valve controls the flow of blood out of the left ventricle of the heart, to the aorta (the body’s main artery).1 The aortic valve opens to allow blood to flow from the heart out to the rest of the body; it then closes to stop any blood leaking back into the heart. In patients with aortic stenosis (AS), the narrowing of the aortic valve opening creates increased resistance to the flow of blood from the left ventricle to the aorta which can in turn lead to heart failure or, in severe cases, sudden death.2

Guidelines published by the Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology and the European Association for Cardio-Thoracic Surgery in 2012 recommend that aortic valve replacement is the main option for treatment of aortic stenosis.3 Aortic valve replacement (AVR) is necessary depending on patient disease severity and has usually resulted in a patient’s aortic valve being stenosed (narrowed)4 following acquired (or degenerative) aortic valve diseases.5

Conventional AVR has a relatively high success rate with surgical AVR associated with a perioperative mortality risk of approximately 1–3% in patients younger than 70 years undergoing isolated AVR, increasing to 4–8% when combined with coronary artery bypass grafting.3

However, not all patients are suitablefor surgery. Several factors affectpatient’s suitability for surgery. As an example, olderage, left ventricular dysfunction or neurological dysfunction are associated with high operative risks. As a consequence a large number of patients with severe aortic stenosis (up to 33%) do not undergo surgery.6

Although AVR is considered the only curative treatment known to improve symptoms and survival in patients with severe, symptomatic aortic stenosis, perioperative mortality increases among high-risk patients (due to older age and comorbidities). Transcatheter aortic valve implantation (TAVI) is an emerging, catheter-based technology that allows for implantation of a prosthetic valve without open-heart surgery and without removing the diseased valve.7 TAVI is currently reserved for patients considered too high-risk for conventional AVR surgery or have other contraindications to open heart surgery. This is due, in part, to the complications that can follow a TAVI procedure.

There is a growing interest in minimally invasive access for aortic valve surgery, which reduces surgical trauma and pain to the patient and potentially allows a faster recovery.8 The upper hemi-sternotomy provides good aortic valve exposure, with numerous possible advantages. Nevertheless, some surgeons remain sceptical about limited access surgery because it is technically more demanding. 

Perceval sutureless solution in AVR

Sutureless and rapid-deployment bioprostheses could alleviate these concerns by improving ease of implantation. Since their introduction in clinical practice for AVR, they appeared to provide enhanced implantability and favourable haemodynamics. Implants of sutureless bioprosthesis are increasingly performed, and the first meaningful findings have been released and herewith analysed.

Perceval sutureless valve is a bioprosthetic valve designed to replace the diseased valve or malfunctioning prosthetic aortic valve via open-heart surgery in full sternotomy, or minimally invasive approaches (Figure 1). 

The stent fits the anatomy of the aorta and follows its movement during the entire cardiac cycle. It is designed to distribute the stresses in order to minimise the risk of damage to the aortic root. No sutures are required to fix the valve in place. This potentially reduces the risk damage to the aorta, reduces the operation time and facilitates patients’ faster recovery.9 The reduced profile of the valve, when mounted in its dedicated holder, enhances visibility and control for the surgeon (Figures 2 and 3). 

Clinical results of Perceval valve 

Gilmanov et al10 demonstrated that the minimally invasive approach allows for better results than traditional approaches. Ranucci and colleagues reported that aortic cross-clamp time was an independent predictor of severe cardiovascular morbidity, with an increased risk of 1.4% per one-minute increase, proving that shorter procedures have a positive impact on patient outcome.11–13 Perceval aortic valve offers the opportunity to leverage both the advantages by means of a shorter and easier procedure and a reproducible technique in every (traditional and minimally invasive) approach.

In our experience, Perceval compares favourably with conventional valves, and the evidence we collected shows how shorter procedural time in the patient treated with Perceval is associated with better clinical outcomes and reduced hospital costs.

From March 2010 to April 2013, 566 patients underwent AVR with bioprostheses; of these, 166 received a sutureless valve, and 400 received a stented valve. A propensity-score analysis was used to create two groups (sutureless and stented) with 82 matched pairs with comparable preoperative characteristics. Hospital outcome, follow-up, and health care resource consumption were analysed.

The in-hospital mortality rate was similar in the matched groups but a different outcome was recorded for hospital and ICU stay, atrial fibrillation, and need for blood transfusion. Perceval patients showed faster recovery from the operation (Table 1).

Perceval valve haemodynamics

The valve has an excellent haemodynamic performance due to a design that aims to optimise blood flow. The geometric orifice area is maximised, thanks to the absence of a suturing ring,14 providing excellent haemodynamics with stable results over time (Figure 4).

Perceval health economics

Clinical benefits are associated with the use of sutureless valves, that allow a quicker and easier implant limiting drawbacks associated to longer and complex surgical operations, thereby having a positive impact on overall survival, hospitalisation length of stay, rehabilitation and incidence of adverse events coupled with a significant impact on costs savings from the perspectives of hospitals, local health authorities and the National Health Service.

Pradelli et al15 estimated the economic impact of using sutureless valve developing a model that relies on the effects on the outcomes that were significantly influenced by cross clamp times11 and by the surgical technique (ICU length of stay, total hospital length of stay, renal complication rate, blood loss and bleeding, ventilation time). Results showed that Perceval is a cost-saving treatment both in isolated and concomitant AVR compared with conventional ‘sutured’ valves, with savings ranging from 18% to 30%.

Our experience is summarised in a retrospective observational study16 that compared Perceval with traditional AVR. A propensity-score analysis was used to create two groups (sutureless and stented) with 82 matched pairs with comparable pre-operative characteristics. Hospital outcome, follow-up, and health care resource consumption were compared and we found that Perceval not only reduces some resource consumption but also reduces hospital costs per patient. Perceval showed a 25% cost savings compared with traditional AVR mainly deriving from reductions in hospitalisation and diagnostic costs (Figure 5).

These results show that the incremental cost due to the adoption of new technology can be offset by savings from a reduced resources consumption of the other most relevant key cost drivers.

Our experience is confirmed by a retrospective observational study carried out in Leuven Hospital in Belgium.17 The authors showed that, in spite of a cohort with higher risk patients, Perceval has shown a consistent and solid optimisation of resources (operating room utilisation, transfusions, ICU and ward stay). Authors conclude that: ‘‘Sutureless aortic valves allow hospitals to achieve shorter hospitalisation times and significant cost savings, when compared with traditional aortic valves.” Estimated savings using the Perceval valve compared with a traditional valve in AVR are shown in Figure 6.

Evidence from these two real-life experiences confirm that the additional clinical benefits of a reduced risk of severe complications and the additional value of a faster and easier implant will be sustainable for the health care system and will potentially allow a more efficient use of resources for the hospital.

Conclusions

Sutureless aortic bioprosthetic valves have been recently introduced into clinical practice and bear the potential of easy implantation, thereby shortening surgical time. The use of the Perceval bioprosthesis combines the advantages of stentless valves in terms of haemodynamic performance with those of a simple implantation technique using a minimally invasive approach. Therefore, combining the advantage of shorter procedural times with a consequent better outcome and a correlate healthcare costs reduction, sutureless AVR may be the first-line treatment for patients who underwent AVR with a bioprosthesis. 

The good clinical outcomes and the absence of SVD reported in a recent analysis18 confirm the excellent performance of this valve in a mid-term perspective. This, together with increasing clinical experience, gives a foundation to the expectation of good long term durability, foreseeing Perceval valve increasing adoption in AVR treatment.

References

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