Aortic valve replacement with 'stentless' versus mechanical prosthesis: what difference in postoperative ICU course?

Introduction

Aortic valve prosthesis determine a transvalvular gradient (Δp) with changes in aortic flow that can affect left ventricular geometry and function, implanted prosthesis and aortic route. In order to improve prognosis a new prosthesis has been proposed, the so called 'stentless valve' (SV), whose main characteristic is the absence of the supporting ring. Aim of our study was to evaluate if such valve could influence early postoperative course in ICU.

Methods

Forty patients, age 67 ± 11 and EF 56 ± 14, undergoing aortic valve replacement were enrolled. Nineteen patients, 12 with aortic stenosis (AoS) and seven with insufficiency (AoI) underwent SV implantation (group S); 21 patients, 13 with AoS and eight with AoI, received mechanical valve (group M). Anaesthesia with remifentanil and propofol, moderate hypothermia (30°C) and anterograde blood cardioplegia were used. In all cases mechanical ventilation (MV) and intubation time, need for inotropic support and blood loss were registered during ICU stay.

Results

No differences were found in duration of MV (125 ± 30 min in group S versus 136 ± 12 min in group M, P > 0.05) and intubation (3 h in group S versus 3.4 h in group M, P > 0.05) in patients with aortic stenosis. In patients with AoI MV and intubation time was shorter in group S (respectively 140 ± 25 min versus 155 ± 18 min in group M. P < 0.05; 3.9 h versus 4.5 h in group M, P < 0.05). No differences were observed in blood loss between two groups, nor in dopamine dosage (5.4 μg/kg/min versus 6.6 μg/kg/min, P < 0.05).

Discussion

Our results show no differences in early postoperative outcome in patients with AoS when treated with mechanical or SV. Vice versa SV seems to improve ICU course of patients with AoI, with regard to duration of MV and intubation. Other studies with echocardiography are necessary to clear if these differences can be due to a lower aortic transvalvular gradient of SV.