Expandable external support device to improve Saphenous Vein Graft Patency after CABG

Objectives: Low patency rates of saphenous vein grafts remain a major predicament in surgical revascularization. We examined a novel expandable external support device designed to mitigate causative factors for early and late graft failure. Methods: For this study, fourteen adult sheep underwent cardiac revascularization using two vein grafts for each; one to the LAD and the other to the obtuse marginal artery. One graft was supported with the device while the other served as a control. Target vessel was alternated between consecutive cases. The animals underwent immediate and late angiography and were then sacrificed for histopathologic evaluation. Results: Of the fourteen animals studied, three died peri-operatively (unrelated to device implanted), and ten survived the follow-up period. Among surviving animals, three grafts were thrombosed and one was occluded, all in the control group (p = 0.043). Quantitative angiographic evaluation revealed no difference between groups in immediate level of graft uniformity, with a coefficient-of-variance (CV%) of 7.39 in control versus 5.07 in the supported grafts, p = 0.082. At 12 weeks, there was a significant non-uniformity in the control grafts versus the supported grafts (CV = 22.12 versus 3.01, p < 0.002). In histopathologic evaluation, mean intimal area of the supported grafts was significantly lower than in the control grafts (11.2 mm^2 versus 23.1 mm^2 p < 0.02). Conclusions: The expandable SVG external support system was found to be efficacious in reducing SVG’s non-uniform dilatation and neointimal formation in an animal model early after CABG. This novel technology may have the potential to improve SVG patency rates after surgical myocardial revascularization

Inhibition of vein graft remodeling and neo-intimal formation using a cobalt chrome external support

Objective: Despite significant advances in the understanding of vein graft remodeling during the post-implantation, vein graft disease is still a major limitation of surgical revascularization. The study objective was to evaluate the performance of a new cobalt chrome external support device designed to mitigate vein graft remodeling and development of intimal hyperplasia. Methods: Bilateral carotid interposition of reversed saphenous vein graft segments was performed in seven&#8207; adult sheep. Following completion of the first anastomosis, randomization was performed to allocate the experimental and control grafts in each animal. Post-procedure, Doppler US was used to assess grafts lumen diameter at T0 and then 3-5 and 12-14 weeks after surgery. At 12-14 weeks, all sheep underwent angiography to assess grafts patency and lumen uniformity (coefficient of variance - CV) after which they were sacrificed, and all grafts were harvested for microscopic histological analysis. Results: Baseline (T0) internal diameter was not significantly different between the supported and unsupported grafts. At twelve to fourteen weeks, the internal diameter of supported grafts remained unchanged and was significantly lower compared to the non-supported grafts (6.6mm±0.4mm vs. 12.8mm±4.0mm respectively, p= 0.0001). Percentage coefficient of variance (%CV) was 4.6%±4.3 in the supported grafts as opposed to average CV% of 14.7%±6.5 in the non-stented group (p=0.011). Neointimal area was significantly lower in the stented compared to the non-stented group (1.4 mm2±3.3mm2 versus 9.6mm2±9.7mm2 respectively, p=0.009). Conclusions: External support of vein grafts using a braided cobalt chrome external stent reduces early vein graft remodeling and mitigates the development of neointimal hyperplasia. [Arch Clin Exp Surg 2018; 7(3.000): 108-115

Usability, performance and safety of a new device for degenerative mitral regurgitation: in vivo chronic evaluation.

OBJECTIVES: This study aimed to evaluate the usability, performance and safety of an innovative mitral valve device in the chronic setting characterized by an intraventricular bridge, which enables artificial chordae anchoring and/or direct posterior leaflet fixation.METHODS: Ten female sheep were employed and underwent device implantation. Any interference of the device with leaflet motion, ease of device use, correct chordae length estimation and implantation were evaluated. Post-procedural valve competence and device performance were verified by periodic postoperative echocardiograms and laboratory examinations. Following euthanasia, gross anatomy and histology evaluation of the hearts and valves were performed to detect tissue abnormalities and inflammation reaction related to the device.RESULTS: The procedure was successfully completed in all 10 sheep. Lengths of the 2 chordae implanted were 23 (21.5-24) mm and 23 (22.5-24) mm. The time required to suture both pairs of the artificial chordae was 2.7 +/- 0.7 min. At the 3-month follow-up, left ventricular function was normal. The transvalvular peak pressure gradient was 9 (7.5-10) and the mean gradient was 4 (3.5-4) mmHg. Upon necropsy and histological evaluation, no damage to left ventricle wall, valve leaflets, chordae and papillary muscles and absence of thrombus formation and inflammatory reaction were observed. Radiological images showed neither fracture of the device nor calcifications. Laboratory tests showed no signs of haemolysis.CONCLUSIONS: In vivo late tests confirmed the ease of correct chordal length estimation prior to implantation, short operative time and usability in flailed anterior leaflet repair. The absence of negative impact of the device on mitral leaflets motion, function and structure and successful repair might suggest that the device would be useful in complex degenerative mitral disease

JDP2 and ATF3 deficiencies dampen maladaptive cardiac remodeling and preserve cardiac function.

c-Jun dimerization protein (JDP2) and Activating Transcription Factor 3 (ATF3) are closely related basic leucine zipper proteins. Transgenic mice with cardiac expression of either JDP2 or ATF3 showed maladaptive remodeling and cardiac dysfunction. Surprisingly, JDP2 knockout (KO) did not protect the heart following transverse aortic constriction (TAC). Instead, the JDP2 KO mice performed worse than their wild type (WT) counterparts. To test whether the maladaptive cardiac remodeling observed in the JDP2 KO mice is due to ATF3, ATF3 was removed in the context of JDP2 deficiency, referred as double KO mice (dKO). Mice were challenged by TAC, and followed by detailed physiological, pathological and molecular analyses. dKO mice displayed no apparent differences from WT mice under unstressed condition, except a moderate better performance in dKO male mice. Importantly, following TAC the dKO hearts showed low fibrosis levels, reduced inflammatory and hypertrophic gene expression and a significantly preserved cardiac function as compared with their WT counterparts in both genders. Consistent with these data, removing ATF3 resumed p38 activation in the JDP2 KO mice which correlates with the beneficial cardiac function. Collectively, mice with JDP2 and ATF3 double deficiency had reduced maladaptive cardiac remodeling and lower hypertrophy following TAC. As such, the worsening of the cardiac outcome found in the JDP2 KO mice is due to the elevated ATF3 expression. Simultaneous suppression of both ATF3 and JDP2 activity is highly beneficial for cardiac function in health and disease

Usability, performance and safety of a new device for degenerative mitral regurgitation: in vivo chronic evaluation

OBJECTIVES: This study aimed to evaluate the usability, performance and safety of an innovative mitral valve device in the chronic setting characterized by an intraventricular bridge, which enables artificial chordae anchoring and/or direct posterior leaflet fixation.METHODS: Ten female sheep were employed and underwent device implantation. Any interference of the device with leaflet motion, ease of device use, correct chordae length estimation and implantation were evaluated. Post-procedural valve competence and device performance were verified by periodic postoperative echocardiograms and laboratory examinations. Following euthanasia, gross anatomy and histology evaluation of the hearts and valves were performed to detect tissue abnormalities and inflammation reaction related to the device.RESULTS: The procedure was successfully completed in all 10 sheep. Lengths of the 2 chordae implanted were 23 (21.5-24) mm and 23 (22.5-24) mm. The time required to suture both pairs of the artificial chordae was 2.7 +/- 0.7 min. At the 3-month follow-up, left ventricular function was normal. The transvalvular peak pressure gradient was 9 (7.5-10) and the mean gradient was 4 (3.5-4) mmHg. Upon necropsy and histological evaluation, no damage to left ventricle wall, valve leaflets, chordae and papillary muscles and absence of thrombus formation and inflammatory reaction were observed. Radiological images showed neither fracture of the device nor calcifications. Laboratory tests showed no signs of haemolysis.CONCLUSIONS: In vivo late tests confirmed the ease of correct chordal length estimation prior to implantation, short operative time and usability in flailed anterior leaflet repair. The absence of negative impact of the device on mitral leaflets motion, function and structure and successful repair might suggest that the device would be useful in complex degenerative mitral disease

Evaluation of an Innovative Device for Mitral Valve Regurgitation: Experimental Acute In Vivo Results

: Objective: Currently, mitral prosthetic rings are intended only to reshape the annulus. We present in vivo results of an innovative device characterized by an intraventricular segment designed to enable artificial chordae implantation and simplify leaflets and subvalvular apparatus correction. Methods: Eight sheep were employed. The first 4 underwent solely device implantation. In the last 4, primary chordae of the anterior leaflet (A2) were torn to induce severe mitral regurgitation. The severed chordae were replaced by 2 pairs of 5-0 Gore-Tex artificial chordae previously measured and anchored to the device bridge. Ease of device and chordae implantation were evaluated, and postprocedural valve competence was verified by postoperative echocardiogram. Results: The procedure was completed in all 8 sheep. In the 4 sheep with induced severe mitral regurgitation, repair could be achieved by means of artificial chordae implantation. Length of the 2 chordae implanted was 21.6 ± 2 mm and 22 ± 3 mm, respectively. The time required to suture the artificial chordae was 2.5 ± 1.2 min. Postoperative echocardiograms showed normal left ventricular ejection fraction and free motion of the mitral leaflets. Mitral regurgitation was absent in 5 cases and trivial in 3. The transvalvular peak pressure gradient was 9.5 ± 6 mm Hg, and mean gradient was 3.7 ± 4 mm Hg. Postprocedural evaluation of the heart and mitral valve showed no damage to the left ventricle wall, valve leaflets, chordae, and papillary muscles. Conclusions: In vivo tests confirm safety of the device, ease of chordal length estimation prior to implantation, short operative time, and no negative impact of the device on mitral leaflet motion, function, and structure