In vitro comparison of three techniques for ventriculo-aortic junction annuloplasty

Abstract

In aortic valve repair, reduction and stabilization of the ventriculo-aortic junction (VAJ) is generally recommended. In this in vitro study, we compare three techniques of annuloplasty: the subcommissural annuloplasty (SCA), the internal ring (IR) and the external ring (ER) annuloplasty. Ten fresh porcine aortic valve preparations were tested in a pulsatile mock loop. Each sample was tested untreated (baseline: B). The annuloplasty techniques were then performed successively in each sample. Each technique was tested, then removed and the following technique performed. SCA was applied at 50% of interleaflet triangle height; the ER and IR were applied with a moderate reduction (15-20%) of the VAJ. Hydrodynamic, video and echographic parameters were collected. Flow rate and arterial pressure were maintained consistently between groups. Effective orifice area decreased significantly with each annuloplasty technique compared with baseline (P<0.001). Mean transvalvular pressure drop was significantly higher in the ER and IR vs SCA (P=0.007). Annuloplasty reduced valve opening and closing time in comparison to baseline. Echocardiography confirmed that the VAJ experienced a greater reduction with the ER and IR vs SCA. A narrowing of the lower third of the sinuses of Valsalva was observed after the ER, and subvalvular narrowing was observed after the IR. Valve coaptation increased with all annuloplasty techniques. The three annuloplasty techniques examined demonstrated differential effects on aortic valve function and root morphology. The ER and IR have greater potential to reduce VAJ diameter in comparison to SCA. The IR induced a subvalvular remodelling of the VAJ, whereas the ER induced a paravalvular remodelling.