Measuring chordae tension during transapical neochordae implantation: Toward understanding objective consequences of mitral valve repair

Abstract

Objectives: Complex structure of mitral valve and its central position in the heart limit assessment of mitral function to standardized calculated parameters assessed using medical imaging (echocardiography). Novel techniques, which allow mitral valve repair (MVr) in a beating heart, offer the opportunity for innovative objective assessment in physiologic and pathologic conditions. We report, to our knowledge, the first data of real-time chordal tension measurement during a transapical neochordae implantation.

Methods: Seven patients with severe degenerative mitral regurgitation due to posterior prolapse underwent transapical MVr using the NeoChord DS 1000 (NeoChord Inc, Minneapolis, Minn). During prolapse correction, the tension applied on the neochordae was measured in addition to hemodynamic and echocardiographic parameters.

Results: The traction applied on 1 chorda sustaining the P2 segment was measured at between 0.7 and 0.9 N, and oscillated with respiration. When several neochordae were set in tension, this initial tension was spread homogeneously on each chorda (mean sum of the amplitude of tension 0.98 ± 0.08 N). To achieve an optimal echocardiographic correction, a complementary synchronous traction on all chordae was required. During this adjustment, the sum of the tension decreased (mean 12 ± 2%; P = .018), suggesting that when normal physiology was restored, the valvular apparatus was in a low-stress state. This method allowed us to apply a precise and reproducible technique, leading to a good procedural success rate with a low morbidity and mortality rate.

Conclusions: The tension applied on chordae during transapical implantation of neochordae for degenerative mitral regurgitation can be measured, providing original data about the objective consequences of MVr on the mitral apparatus.

Keywords: NeoChord; chordal tension; mitral physiology; mitral valve repair; transapical.