Sutureless aortic valve bioprothesis '3F/ATS Enable'--4.5 years of a single-centre experience.

Background: Management of patients with acquired heart malformations, including aortic valve disease, is still challenging. Due to ageing of population, patients undergoing valve surgery are older than in the past. The 3F Therapeutics, conducting a programme of construction of heart valves for transarterial or transapical implatation, prepared the 'Enable' bioprosthetic valve for sutureless insertion in the aortic position. The first world implantation was performed in our Department on 13 January 2005.

Aim: To present our experience, qualification criteria and methods of implantation of sutureless bioprosthesis of aortic valve 'Enable'.

Methods: The 'Enable' valve is a tubular structure, tailored and sutured of equine pericardium, treated with glutaraldehyde, and mounted on an openwork Nitinol" alloy stent. It consists of two distal rings connected with three vertical sticks. The characteristic property of nitinol is thermoplaticity: due to refrigeration it becomes elastic and easy to bend, after rewarming returns to the initial dimensions and shape, remaining stable at the body temperature. Distension of the nitinol ring make possible strong mounting of the valve in aortic annulus. The examined group consised of 27 patients (16 males, 11 females), aged 60-78 years (average 69.5), with advanced aortic valve disease, left ventricular hypertrophy, and aortic gradient up to 102 mmHg. Exclusion criteria were: severe annular deformations or bicuspid aortic valve, other valves' malformations, coronary disease, severe other comorbidities or no agreement for 'Enable' valve implantation. The patients were operated using extracorporeal circulation, general moderate hypothermia and cold crystalloid cardioplegia. Care was taken to remove calcifications, estimate of aortic annulus geometry, valve size selection, and orientation of the valve toward coronary ostia The mounting time was approximately one min, and the aorta cross-clamp time was reduced to 26-56 min, mean 30 min.

Results: There was no mortality in the perioperative period, and during 3 months to 4.5 years of follow-up. No severe complications were present after surgery. One patient needed reoperation on post operative day 4 due to severe perivalvular leak. One other patient presented discrete leak with no need for intervention. The clinical improvement of one to three NYHA classes was observed. Echocardiographic and MSCT examinations confirmed adequate position of the valves, no structural deteriorations, normal movement and coaptation of the leaflets. The average maximal transvalvular gradient was 11.6 mmHg and the mean gradient--6.8 mmHg, which remained stable during the follow-up period. No thromboembolic or infective complications were present.

Conclusions: (1) The 'Enable' aortic bioprosthetic valve has very good hemodynamic properties. (2) Self-expanding thermoplastic nitinol-made ring allows permanent stable mounting. (3) The quick fixation (about 1 min) significantly shortens the operation time. (4) The 'Enable' valve seems to be suitable for patients with increased periopertive risk.