Off-pump transapical mitral valve replacement☆ (original) (raw)

Off-pump transapical mitral valve replacement. Discussion

European Journal of Cardio Thoracic Surgery, 2009

Objective: Percutaneous valve replacement was recently introduced, and reports of early clinical experience have already been published. To date, this technique is limited to the replacement of pulmonary and aortic valves in a strictly selected group of patients. The aim of this study was to analyse a self-expanding valved stent for minimally invasive replacement of the mitral valve in animals. Methods: A newly designed nitinol stent was specially designed for this experimental acute study. It comprised of a left ventricular tubular stent with star shaped left atrial anchoring springs and carried a trileaflet bovine pericardial valve. A polytetrafluoroethylene membrane was sutured to envelop the atrial springs and the outside of the ventricular stent. The ventricular anchoring system was the same as in our previously reported results with a similar mitral valved stent. Seven pigs underwent minimally invasive off-pump mitral valved stent implantation. This was performed through a lower ministernotomy and a standard transapical approach under transoesophageal echocardiographic (TEE) guidance was used. Results: The valved stent is fully retrievable and precise deployment and accurate adjustment of its intra-annular position is achievable to eliminate paravalvular leakage. The deployment time ranged from 127 to 255 s and the blood loss from 70 to 220 cc. One animal died of intractable ventricular fibrillation. Mitral regurgitation in all surviving animals was minimal (trace in 5/6 and mild in 1/6 during echo examination; on the contrast ventriculogram no mitral insufficiency was observed except in one documented as mild paravalvular regurgitation). These animals remained haemodynamically stable (6/ 6) and without TEE or ventriculographic changes for 1 h. Conclusion: Implantation of a tricuspid bovine pericardial valved stent in the mitral position is feasible in pigs through a transcatheter approach. This was possible through a smaller delivery system than previously reported. Additional studies are required to demonstrate long-term feasibility, durability, and heart function. #

Transapical mitral valved stent implantation: A survival series in swine

The Journal of Thoracic and Cardiovascular Surgery, 2010

Background. Transcatheter aortic and pulmonary valve replacement is currently being tested in human trials. Efforts to create a valved stent to replace the atrioventricular valves have shown limited success. This is due to their their complex anatomy and function.

Transapical Mitral Valved Stent Implantation

The Annals of Thoracic Surgery, 2008

Mitral valved stent implantation

European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, 2010

To date, transfemoral and trans-apical valved stent implantation techniques are limited to the replacement of pulmonary and aortic valves in a strictly selected group of patients. The current study was designed to assess the short-term follow-up using a mitral valved stent in off-pump technique. A self-expanding, repositionable mitral valved stent was created for trans-apical implantation. Five pigs underwent successful trans-catheter implantation. Data were gathered to assess the animals' haemodynamical stability after stent implantation (n=5), 6h (n=5) and 1 week (n=4). The valved stent function was assessed by trans-oesophageal echocardiography and ventriculogram. Cardiac computed tomography (CT) was used to evaluate positioning of the new implant. Precise valved stent deployment and accurate subsequent adjustment of its intra-annular position allowed for reduction of paravalvular leakage in all animals. The deployment time ranged from 122 to 271 s and blood loss from 65 to 2...

Transcatheter mitral valve implantation: a percutaneous transapical system

Interactive cardiovascular and thoracic surgery, 2017

Despite recent achievements, implantation of a transcatheter mitral valved stent remains challenging. In this study, we present a different approach for implantation of a percutaneous mitral valved stent. Percutaneous transapical access is combined with, respectively, a left-transatrial, right-transatrial/transseptal or transfemoral/transseptal approach for mitral valve stent implantation and secure fixation. The apical fixation and occlusion are ensured with an Amplatzer occluder. This novel approach was tested in 22 porcine hearts in an in vitro setting under the guidance of fluoroscopy (n = 11) and endoscopy (n = 11). The in vitro setup included continuous flushing at 37 °C. We determined the feasibility, time of implantation, stent deployment and stent fixation. Percutaneous mitral valved stent implantation was successful in all cases. Good handling properties and precise positioning were achieved. Time of implantation was comparable in the fluoroscopic and endoscopic groups at ...

Functional Evaluation of the Medtronic Stentless Porcine Xenograft Mitral Valve in Sheep

Circulation, 1999

Background-Recently, renewed interest in allograft and stentless "freehand" bileaflet xenograft mitral valve replacement has arisen. The variability of human papillary tip anatomy and scarcity of donors limit allograft availability, making xenograft mitral valves an attractive alternative; however, these valves require new surgical implantation techniques, and assessment of their hemodynamics and functional geometry is lacking. Methods-Seven sheep underwent implantation of a new stentless, glutaraldehyde-preserved porcine mitral valve (Physiological Mitral Valve [PMV], Medtronic) and were studied acutely under open-chest conditions. A new method of retrograde cardioplegia was developed. Hemodynamic valve function was assessed by epicardial Doppler echocardiography. 3D motion of miniature radiopaque markers sutured to the valve leaflets, annulus, and papillary tips was measured. Six other sheep with implanted markers served as controls. Results-Both papillary muscle tips avulsed in the first animal, leaving 6 other animals. Mitral regurgitation was not observed in any xenograft valve. The peak and mean transvalvular gradients were 4.6Ϯ1.8 mm Hg and 2.6Ϯ1.5 mm Hg, respectively. The average mitral valve area was 5.7Ϯ1.6 cm 2. Valve closure in the xenograft group occurred later (30Ϯ11 ms, PϽ0.015) and at higher left-ventricular pressure (61Ϯ9 mm Hg, PϽ0.001) than in the control group; furthermore, leaflet coaptation was displaced more apically (5.6Ϯ2.2 mm, PϽ0.001) and septally (5.8Ϯ1.5 mm, PϽ0.001), and the anterolateral papillary tip underwent greater septal-lateral displacement (2.7Ϯ1.5 mm, PϽ0.001). Annular contraction during the cardiac cycle was similar in the 2 groups (xenograft 9.2Ϯ4.5% versus control 10.6Ϯ4.5% [meanϮSD; 2-factor ANOVA model]). Conclusions-Successful freehand stentless porcine mitral valve implantation is feasible in sheep and was associated with excellent early postoperative hemodynamics. Physiological mitral valve annular contraction and functional leaflet closure mechanics were preserved. Long-term valve durability, calcification, and hemodynamic performance remain to be determined in models. (Circulation. 1999;100[suppl II]:II-70-II-77.

New evolution in mitral physiology and surgery: Mitral stentless pericardial valve

Annals of Thoracic Surgery, 1995

The human adult mitral valve, with a mean diastolic area of up to 7.6 cm2, excess leaflet surface area for coaptation in systole, mitral annulus-papillary muscle continuity, and systolic constriction of the posterior left ventricular wall around the mitral annulus functions in concert with other components of the left side of the heart. Mitral valve replacement with an artificial valve that interferes with the normal physiology could account for less than adequate late results. A stentless biologic mitral valve substitute has been designed, constructed, and tested. The size of the valve is selected according to the circumference of the excised valve within certain limits. The valve is manufactured of two square or trapezoidal pieces of selected stabilized human autologous or bovine pericardium. The pericardial pieces are sutured together by their lateral margins, thus creating a frusto-conical valvular body. The upper circumference of the valvular body is sutured at the mitral annulus and the lower margin with the new chordae is attached by suture at each papillary muscle. In vitro testing of six stentless bovine pericardial valves in a Rowan-Ash fatigue tester at 1,200 cycles/min revealed a durability of more than 320 million cycles. Clinical use of described technique initiated in 1989 was performed in 18 patients by one surgeon (30 patients in the same institution). The mean valve size was 29 mm circularized diameter. There was no mortality in this group of patients up to 70 months of follow-up. Valve competence was obtained in every case by adequate sizing of the valve. One reoperation was necessary at 3 months for rupture at the papillary muscle suture, early in the series. One late endocarditis required reoperation at 16 months. Sixteen patients were followed up for a mean of 26 months. Echocardiography revealed normal function of the valves with a mean orifice area of 4.43 ± 1.24 cm2 (standard deviation; n = 11) and a mean valve index of 2.6 cm2/m2. There was one late thromboembolic complication in a patient with atrial fibrillation who stopped anticoagulant treatment. All patients with indications are on limited anticoagulation. A mitral stentless pericardial valve with large orifice and mitral annulus-papillary muscle continuity can function adequately up to a current 70 months after the operation.

Development of Off-Pump Mitral Valve Replacement in a Porcine Model

The Annals of Thoracic Surgery, 2015

Purpose-We describe our initial experience with on-bypass and off-bypass (off-pump) mitral valve replacement with the modified version of our novel catheter-based sutureless mitral valve (SMV2) technology, which was developed to atraumatically anchor and seal in the mitral position. Description-The SMV is a self-expanding device consisting of a custom designed nitinol framework and a pericardial leaflet valve mechanism. For the current studies our original device was modified (SMV2) to reduce the delivery profile and to allow for controlled deployment whilst still maintaining the key principles necessary for atraumatic anchoring and sealing in the MV position. Evaluation-Ten Yorkshire pigs underwent successful SMV2 device implantation via a left atriotomy (on-pump N=6; off-pump N=4). Echocardiography and angiography revealed excellent LV systolic function, no significant perivalvular leak, no MV stenosis, no left ventricular (LV) outflow tract obstruction and no aortic valve insufficiency. Necropsy demonstrated that the SMV2 devices were anchored securely. Conclusions-This study demonstrates the feasibility and short-term success of off-pump mitral valve replacement using a novel, catheter-based device in a porcine model.

Double-crowned valved stents for off-pump mitral valve replacement. Commentary and Discussion

European Journal of Cardio Thoracic Surgery, 2005

Objective: An animal model has been designed to assess the feasibility of off-pump mitral valve replacement using valved stents. Methods: Glutaraldehyde-preserved homograft was sutured inside a prosthetic tube (Dacron). Then, two self-expandable nitinol Z-stents were sutured on the external surface of the prosthesis in such a way to create two self-expanding crowns for fixation. In adult pigs and under general anesthesia, the left atrium was exposed through a left thoracotomy and atrio-ventricular roadmapping was performed with intravascular ultrasound (IVUS) and fluoroscopy. The double-crowned valved stents were loaded into a delivery sheath. The sheath was then introduced into the left atrium and the valved stents was deployed in mitral position in such a way that the part in between the two stents was at the level of the mitral annulus. Intracardiac Unltrasound (ICUS) was used to assess the valve function. Hemodynamic parameters were gathered as well. Animal survived for no more than 3 h after the valve deployment and gross anatomy examination of the left heart was carried out. Results: The mean height of the valved stents was 29.4G0.2 mm, with an internal diameter of 20.4G1.0 mm, and an external diameter of 25.5G0.8 mm. The procedure was successfully carried out in eight animals. In vivo evaluation showed a native mitral annulus diameter of 24.9G0.6 mm, and a mean mitral valve area of 421.4G17.5 mm 2 . ICUS showed a mild mitral regurgitation in three out of eight animals. Mean pressure gradient across the valved stents was 2.6G3.1 mmHg. Mean pressure gradient across the left ventricular outflow tract (LVOT) was 6.6G5.2 mmHg. The mean survival time was 97.5G56.3 min (survival time range was 40-180 min). One animal died due to the occlusion of the LVOT because of valved stents displacement. Postmortem evaluation confirmed correct positioning of the valved stent in the mitral position in seven out of eight animals. No atrial or ventricular lesions due to the valved stents were found. Conclusions: Off-pump implantation of a self-expandable valved stent in the mitral position is technically feasible. Further studies will assess if this procedure is also feasible in humans.

Off-pump transapical mitral valve replacement☆ (original) (raw)

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