Transapical mitral valved stent implantation: Enhanced survival and decreased paravalvular leakages

- Transapical mitral valved stent implantation was performed off-pump in 8 pigs.
- Newly developed prototype shows secure deployment and correct position.
- No PVL were detected directly after implantation of the newly developed prototype.
- Minimal gradients, normal longitudinal function over a period of up to three months
- Stent fractures with clinical impact were avoided.

Background/ObjectivesThis study presents the recent results of transapical implantation of a new design of a mitral valved stent with up to three months follow-up.MethodsA self-expanding re-designed mitral valved stent was implanted via transapical approach into the beating heart of eight pigs. Echocardiographic- and hemodynamic parameters were assessed before (n = 8), at 1 h (n = 8), at one month (n = 6), at two months (n = 2), and at three months (n = 1) after implantation and a cardiac CT was conducted.ResultsThe stent was successfully deployed in all animals. Two animals died within the first month due to incorrect fixation force. Echocardiographic evaluation showed low gradients (3.9 ± 1.4 mm Hg and 1.9 ± 0.8 mm Hg across the valved stent and aortic valve) and a normal mitral annular plane systolic excursion (1.1 ± 0.2 cm) after one month. No paravalvular leakages (PVL) were detected after 1 h. The pulmonary artery pressure did not increase after valved stent implantation (p ≥ 0.106). The pulmonary capillary wedge pressure (PCWP) slightly increased to 16 ± 3 mm Hg after one month (p = 0.033). The left ventricular end-diastolic pressure was mildly elevated (15.8 ± 8.6 mm Hg) after one month.ConclusionsSecure deployment and correct position of the valved stents were reproducibly achieved in the off-pump implantation procedure. No paravalvular leakages after 1 h as well as low gradients, few stent fractures and a normal longitudinal function after one month were achieved with this newly developed and well-aligned prototype. However, a number of challenges have been identified during this study and potential for improvement has been identified.