Materials and Methods

Study design

In this retrospective longitudinal cohort study, data of all adult patients with aortic valve disease who underwent AVR with a Perceval® prosthetic valve between February 2015 and October 2020 in Hospital de Santa Maria (Lisbon, Portugal) was retrospectively collected from an available hospital database. Approval of the study and access to the data was granted by the ethical committee of the hospital involved (Comissão Ética Centro Hospitalar Lisboa Norte, identification number: 510/18).

Patients

Data collected included demographics and preoperative characteristics, such as comorbidities, EuroSCORE II, presence of atrial fibrillation or pacemaker, left ventricular (LV) function and history of previous cardiac surgery. We also collected intraoperative data, such as the aortic cross-clamping and CPB times, size of the valves implanted and transvalvular gradients, as well as in-hospital stay and postoperative complications.
Endpoints were the clinical and hemodynamic performance, safety and durability of the Perceval valve in AVR, evaluated through the following criteria: mortality and overall long-term survival, structural valve deterioration, operatory times (aortic clamping and CPB times), mean ICU and total hospital stay, postoperative complications - including PPI and infection rates (respiratory, urinary and/or bacteremia of unknown origin), endocarditis, stroke, early mortality (defined as in-hospital or up to 30 days after surgery), abnormal bleeding (defined as > 2ml/kg/h in first 2-3 hours, > 1ml/kg/h in the next 3 hours and/or > 0.5ml/kg/h in 12 hours), new-onset atrial fibrillation (paroxysmal, persistent or permanent), significant renal dysfunction (14) and need for intra-aortic balloon pump, surgical exploration for bleeding, renal replacement support (performed through continuous veno-venous hemodiafiltration) or aminergic support >24h (performed with at least one of the following: epinephrine, norepinephrine, dobutamine) - and postoperative echocardiographic findings.

The Perceval®valve

The Perceval ® prosthetic valve (Sorin Group, Saluggia, Italy) consists in 3 bovine pericardial cusps mounted on a self-expanding nitinol stent comprising two rings, allowing for stabilization simultaneously at the aortic annulus and at the sinotubular junction (STJ), and nine vertical struts covered by a thin coating of Carbofilm™, to improve biocompatibility. The stent holds the valve in place without any permanent suture, by exerting radial force on the patient’s aortic annulus and aortic root. It is also flexible, allowing it to adapt to the anatomy of the aorta and its movements, thus relieving the stress on the leaflets. The valve is folded up by collapsing the inflow and outflow rings with an atraumatic compression device, allowing the pericardial leaflets not to be crimped and remain mobile, ensuring they are not damaged (15) - in contrast to the necessary crimping of the TAVI, in which the leaflet’s collagen fibers are damaged (10). The Perceval ® valve is currently available in four sizes: S, to be implanted in annular sizes from 19 to 21 mm, M from 22 to 23 mm, L from 24 to 25 mm and XL for patients with annular sizes of 27 mm (6).
Although the concept of sutureless bioprosthesis exists for over 40 years (16), the first reports evaluating implantation feasibility and valve safety in humans were only released in 2007. It was CE approved in 2011 and FDA approved in 2016 (17).

Surgical technique

Indications for AVR were in agreement with the ESC/EACTS Guidelines for the management of valvular heart disease at the time of the interventions (18). The surgical approach was either standard median sternotomy or upper J ministernotomy. All patients were operated on or supervised by an experienced surgeon in this procedure. Anaesthetic and surgical techniques were standardized. A high transverse aortotomy close to the epiaortic fat pad was performed, leaving a free edge for closure after implantation of the device. The native calcified aortic valve was excised, and the aortic annulus completely decalcified. Sizing of the annulus was done using dedicated sizers.
Concomitant procedures were performed in line with current department practices and always with the goal of minimizing aortic cross-clamping and CPB times. For instance, aortic graft anastomosis, when needed, was performed prior to cannulation using tangential aortic cross-clamping.
After aortotomy closure in the usual fashion, thorough de-airing with CO2, release of the aortic cross-clamp and weaning from CPB were performed. Valve function was evaluated by intraoperative transesophageal echocardiography in all patients. Following the procedure, patients were transferred to the ICU and managed accordingly. Antiplatelet therapy was instituted. (19).

Statistical analysis

Statistical analysis was performed using IBM SPSS Statistics v27.1 (New York, United States of America). Categorical variables are reported as absolute and relative frequencies. For continuous data, means, median and standard deviations were calculated. Cumulative survival and freedom from events were estimated using the Kaplan–Meier method, with 95% confidence intervals.