New Self-Expanding Transcatheter Valve for Off-Pump Transatrial Mitral Valve-In-Ring Implantation.

OBJECTIVES To validate a self-expanding transcatheter valve for off-pump transatrial mitral valve-in-ring (VIR) implantation via a left thoracotomy. METHODS Mitral valve annuloplasty was performed via sternotomy during cardiopulmonary bypass on 9 pigs. After successful weaning from extracorporal circulation, the custom-made, self-expanding transcatheter VIR device was deployed under fluoroscopic guidance within the annuloplasty ring via a left thoracotomy. Hemodynamic data before and after the implantation were recorded. Mitral annulus diameter and valve area were measured by echocardiography. Transvalvular and left-ventricular outflow-tract pressure gradient were measured invasively. RESULTS Eight successful implantations were performed. Implantation failed in 1 pig because of difficulty with technical delivery of the sheath. Mean transatrial procedure time was 12.6 ± 1.7 min. Hemodynamic status during transatrial implantation was stable, and differences were not statistically significant. Mean mitral annulus diameter and mean mitral orifice area were 2.32 ± 0.2 and 3.84 ± 0.55 cm2, respectively. Mild regurgitation was detected in 7 animals and moderate regurgitation in 1. Mean gradients were 6.1 ± 5.0 mm Hg across the device. Postmortem examination confirmed adequate positioning of devices within the annuloplasty ring. CONCLUSIONS This custom-made transcatheter device allows for safe and reproducible off-pump transatrial mitral VIR implantations. Transatrial access is a promising route to facilitate VIR implantations. Our custom-made stent-valve may be suitable for VIR procedures

New Self-Expanding Transcatheter Valve for Off-Pump Transatrial Mitral Valve-In-Ring Implantation.

OBJECTIVES To validate a self-expanding transcatheter valve for off-pump transatrial mitral valve-in-ring (VIR) implantation via a left thoracotomy. METHODS Mitral valve annuloplasty was performed via sternotomy during cardiopulmonary bypass on 9 pigs. After successful weaning from extracorporal circulation, the custom-made, self-expanding transcatheter VIR device was deployed under fluoroscopic guidance within the annuloplasty ring via a left thoracotomy. Hemodynamic data before and after the implantation were recorded. Mitral annulus diameter and valve area were measured by echocardiography. Transvalvular and left-ventricular outflow-tract pressure gradient were measured invasively. RESULTS Eight successful implantations were performed. Implantation failed in 1 pig because of difficulty with technical delivery of the sheath. Mean transatrial procedure time was 12.6 ± 1.7 min. Hemodynamic status during transatrial implantation was stable, and differences were not statistically significant. Mean mitral annulus diameter and mean mitral orifice area were 2.32 ± 0.2 and 3.84 ± 0.55 cm2, respectively. Mild regurgitation was detected in 7 animals and moderate regurgitation in 1. Mean gradients were 6.1 ± 5.0 mm Hg across the device. Postmortem examination confirmed adequate positioning of devices within the annuloplasty ring. CONCLUSIONS This custom-made transcatheter device allows for safe and reproducible off-pump transatrial mitral VIR implantations. Transatrial access is a promising route to facilitate VIR implantations. Our custom-made stent-valve may be suitable for VIR procedures

Correction: Physiological Disturbance May Contribute to Neurodegeneration Induced by Isoflurane or Sevoflurane in 14 Day Old Rats

BACKGROUND: Volatile anesthetics are widely used in pediatric anesthesia but their potential neurotoxicity raise significant concerns regarding sequelae after anesthesia. However, whether physiological disturbance during anesthetic exposure contributes to such side effects remains unknown. The aim of the current study is to compare the neurotoxic effects of isoflurane and sevoflurane in 14 day old rat pups under spontaneous breathing or ventilated conditions. METHODS: Postnatal 14 day rats were assigned to one of five groups: 1) spontaneous breathing (SB) + room air (control, n = 17); 2) SB + isoflurane (n = 35); 3) SB + sevoflurane (n = 37); 4) mechanical ventilation (MV) + isoflurane (n = 29); 5) MV + sevoflurane (n = 32). Anesthetized animal received either 1.7% isoflurane or 2.4% seveoflurane for 4 hours. Arterial blood gases and blood pressure were monitored in the anesthetized groups. Neurodegeneration in the CA3 region of hippocampus was assessed with terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling immediately after exposure. Spatial learning and memory were evaluated with the Morris water maze in other cohorts 14 days after experiments. RESULTS: Most rats in the SB groups developed physiological disturbance whereas ventilated rats did not but become hyperglycemic. Mortality from anesthesia in the SB groups was significantly higher than that in the MV groups. Cell death in the SB but not MV groups was significantly higher than controls. SB + anesthesia groups performed worse on the Morris water maze behavioral test, but no deficits were found in the MV group compared with the controls. CONCLUSIONS: These findings could suggest that physiological disturbance induced by isoflurane or sevoflurane anesthesia may also contribute to their neurotoxicity

More cell death in the spontaneously breathing groups.

<p>Hippocampal cells stained positive for the early apoptosis TUNEL marker immediately after 4-hour anesthesia. Neonatal isoflurane and sevoflurane exposure increased terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling (TUNEL) expression in the spontaneously breathing groups. The results indicate a significant difference compared with the control, but no statistical difference between the isoflurane or sevoflurane mechanically ventilated groups and control group. **p<0.01.</p

Images of the CA3 region in the hippocampus (5 µm) of five groups, the expression of the terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling (TUNEL) apoptosis marker.

<p>Less cell death in the control and mechanically ventilated groups compared with the spontaneously breathing groups. Positively stained cells are chocolate brown, and arrows mark representative TUNEL-positive cells in each group. IS, isoflurane spontaneously breathing group; SS, sevoflurane spontaneously breathing group; IM, isoflurane mechanically ventilated group; SM, sevoflurane mechanically ventilated group.</p

Rats in the spontaneously breathing groups performed worse than other groups in spatial probe testing.

<p>Time spent by each group in the quadrant with the removed platform of each group is shown. Rats exposed to 1.7% isoflurane and 2.4% sevoflurane in chambers did impair short-term spatial learning, the rats spent much less time in the target quadrant than the controls. But no difference between the control group and the isoflurane, or sevoflurane mechanically ventilated group.</p

Physiologic data in 14-day -old rats exposed to 1.7% isoflurane or 2.4% sevoflurane by either spontaneous breathing or mechanical ventilation at the end of each hour during 4-hour anesthesia.

<p>Data presented as mean±standard deviation.</p><p>IS = Isoflurane spontaneously breathing group; SS = Sevoflurane spontaneously breathing group;</p><p>IM = Isoflurane mechanically ventilated group; SM = Sevoflurane mechanically ventilated group.</p><p>pH, PaCO2, PO2 and Glu: *P<0.05, **P<0.01, compared with controls.</p><p>MAP: *P<0.05, **P<0.01, IS compared with IM, SS compared with SM.</p

Rats in the spontaneously breathing groups performed worse than other groups when searching platform.

<p>Time to reach the platform (escape latency, A) and the distance to reach the platform (pathlength, B) were recorded. Data points represent the average of the sum of four daily trials from four different quadrants for 5-day hidden platform trials. Error bars represent the standard deviation. Although all groups improved over the 5-day trial period, A shows that the rats exposed to 1.7% isoflurane or 2.4% sevoflurane in the chamber took more time to search for the platform than those of the control (p<0.001, repeated-measures ANOVA), but no difference was found among the control and mechanically ventilated groups. Similarly, B shows pathlength was much longer in the spontaneously breathing groups than in the control group (p<0.001, repeated-measure ANOVA). No significant difference was observed among the control and mechanically ventilated groups. (p>0.05).</p

Mortality due to anesthesia exposure in the spontaneously breathing groups and the mechanically ventilated groups.

<p>IS = Isoflurane spontaneously breathing group;</p><p>SS = Sevoflurane spontaneously breathing group;</p><p>IM = Isoflurane mechanically ventilated group;</p><p>SM = Sevoflurane mechanically ventilated group.</p><p>Anesthesia mortality in isoflurane and sevoflurane spontaneously breathing groups was significantly higher than isoflurane and sevoflurane mechanically ventilated groups, respectively.</p><p>p<0.05.</p