Introduction:
The posterior ventricular anchoring neochordal (PVAN) repair is a nonresectional, single-suture technique for correcting posterior leaflet prolapse. While this technique has demonstrated clinical efficacy, a possible limitation is the stability of the suture anchored into myocardium as opposed to the fibrous portion of a papillary muscle.
Hypothesis:
We hypothesize that the PVAN suture serves only to position the leaflet for coaptation, after which systolic forces will be distributed throughout the valve, resulting in low peak forces on the suture.
Methods:
A left heart simulator was constructed using 3D printing, tuned to generate physiological pressure and flow waveforms, then validated. Porcine mitral valves (n=9) were dissected and mounted within the simulator. Chordal forces were measured using Fiber Bragg Grating (FBG) sensors, sewn in place using PTFE suture. FBG sensors are strain gauges made of 125
μ
m optical fibers that use reflected peak wavelength changes to measure strain. Hemodynamic and echocardiographic data were also collected. Isolated severe mitral regurgitation (MR) was induced by cutting P2 primary chordae. The valve was repaired using the PVAN technique, anchoring the suture to a customized force-sensing post positioned to mimic
in vivo
placement.
Results:
Forces on 1° and 2° chordae of both anterior and posterior leaflets were significantly elevated in the prolapse condition (
P
< 0.05). PVAN resulted in elimination of MR in all valves, as well as normalization of chordae forces to baseline levels for posterior primary (
P <
0.01
)
, posterior secondary (
P <
0.01
)
, and anterior primary chordae (
P <
0.05
)
, with reduction in anterior secondary chordal forces approaching significance (
P
= 0.055
)
. Peak forces on the PVAN stitch were minimal, even compared to the forces experienced by primary chordae of normal, healthy valves (
P
< 0.05).
Conclusions:
The PVAN technique eliminates MR by effectively positioning the posterior leaflet for optimal coaptation, distributing the forces amongst the subvalvular apparatus. Given the extremely low forces involved, the strength of the ventricular anchoring suture and myocardial anchoring point should not be a limiting factor.
Commentary: A novel cross-species model of Barlow's disease to biomechanically analyze repair techniques in an ex vivo left heart simulator