Off-pump transapical mitral valve replacement: evaluation after one month
ABSTRACT The present study investigates outcomes one month after implanting pigs with a novel mitral valved stent.
A novel nitinol stent custom designed for this study included a bovine pericardial valve. Six pigs received a valved stent into the mitral position by means of the transapical implantation technique. Afterwards, haemodynamic stability and valve function were assessed, immediately after implantation (n = 6), 4 weeks (n = 4) and 8 weeks (n = 1) thereafter using transoesophageal echocardiography (TEE), ventriculography and cardiac computed tomography (CT). Four of 6 surviving pigs were sacrificed at 4 weeks after implantation and one at 8 weeks thereafter.
Optimal deployment and positioning were obtained in all but one animal. This animal died of unrecognized imperfect valved stent positioning after 4 days. The average mean gradient across the new valves and the left ventricular outflow tract (LVOT) were small. Mild regurgitation developed after valved stent deployment in one of six animals just after 1 h, and in none thereafter. All animals exhibited normal haemodynamics after mitral valved stent implantation, and stability was maintained throughout the monitoring period. Migration, embolization and paravalvular leakage were not evident in the remaining animals after 4 and 8 weeks. Gross evaluation revealed that 50-70% of the atrial element was covered by tissue growth at 4 weeks/8 weeks.
This study demonstrates adequate deployment and anchorage of a unique, repositionable mitral valved stent. A good valve function was revealed in animals observed for 4 weeks and in one pig after 8 weeks.
Circulation 11/2014; 130(19):1712-22. DOI:10.1161/CIRCULATIONAHA.114.009881 · 14.95 Impact Factor
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ABSTRACT: Background/Objectives: This study presents the recent results of transapical implantation of a newdesign of a mitral valved stent with up to three months follow-up. Methods: A 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 onemonth (n= 6), at two months (n= 2), and at three months (n= 1) after implantation and a cardiac CT was conducted. Results: The 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 +/- 0.8mmHg 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. Conclusions: Secure 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.The Thoracic and Cardiovascular Surgeon 06/2014; 175(3). DOI:10.1016/j.ijcard.2014.06.007 · 1.08 Impact Factor
Circulation Cardiovascular Interventions 06/2014; 7(3):400-9. DOI:10.1161/CIRCINTERVENTIONS.114.001607 · 6.98 Impact Factor