P102 NEW THREE–DIMENSIONAL ECHOCARDIOGRAPHIC PREDICTING PARAMETERS IN TRANS–VENTRICULAR HEART–BEATING MITRAL VALVE REPAIR WITH NEOCHORDAE: A MONOCENTRIC RETROSPECTIVE STUDY

Background

Trans–ventricular off pump mitral valve (MV) repair with neochordae implantation (Neochord procedure) is a minimally invasive surgical technique for correction of degenerative mitral regurgitation (MR) due to prolapse or flail. The aim of this study was to evaluate mid–term results of patients undergoing this procedure and find new three–dimensional pre–operative echocardiographic parameters to predict MR recurrence at follow–up.

Methods

We performed a retrospective analysis of 72 consecutive patients with severe MR due to prolapse or flail who underwent Neochord procedure at our hospital from March 2015 to February 2021. MV pre–operative anatomical parameters were assessed using 2D TEE, 3D TEE and dedicated three–dimensional (3D) post–processing analysis with dedicated software (QLAB, Philips). TTE follow–up and clinical evaluation were performed at 3 months, 6 months, 1 year and then annually.

Results

Twenty–seven patients were female (37.5%), mean age was 77±9 years. The average preoperative EuroSCORE II was 2.2%±1.5%. Twenty–three patients (32%) had an history of paroxysmal or persistent atrial fibrillation. Procedural success at discharge was achieved in sixty–eight patients (94.5%). Mean follow–up was 30±16 months. Three years follow–up was completed by fifty patients. At three years thirteen patients (26%) presented with recurrence of severe MR or underwent new surgical operation. Prevalence of mild or trace MR at three years follow–up visit was 70%. End–systolic annulus area (12.5±2.5 cm2 vs 14.1±2.6 cm2; p = 0.038), end–systolic annulus diameter (13.2±1.2 cm vs 14±1.3 cm; p = 0.042) and indexed left atrial volume (59±17 ml/m2 vs 76±37 ml/m2; p = 0.041) were lower in patients with residual MR less than moderate (MR < 3+/4+). Three–dimensional indexes specifically focused on coaptation reserve and annular disfunction were the best predictors of MR < 3+/4+ at follow–up, in particular diastolic sum of the leaflets/end–systolic annulus area ([AUC] 0.74; p = 0.029) and systo–diastolic annulus area fractional change ([AUC] 0.743; p = 0.035). Furthermore, each of these annular parameters, calculated using dedicated 3D software, were predictive of residual MR, whereas annular 2D dimensions were not (p = 0.347).

Conclusion

In patients with degenerative MR treated with Neochord procedure, 3D analysis focused on annular measures and coaptation indexes, that included 3D annular dimensions, predicts better MR relapse than conventional 2D parameters.

C40 THREE–DIMENSIONAL FINGER TEST: A NEW ECHOCARDIOGRAPHIC METHOD TO LOCATE THE BEST ACCESS SITE DURING NEOCHORD PROCEDURE

Background

The NeoChord procedure is a trans–ventricular, beating–heart chordal implantation for severe degenerative mitral valve regurgitation due to prolapse or flail leaflet and it is performed using a dedicated device (DS 1000 system, NeoChord, Inc. St. Louis Park, MN). The use of the transesophageal echocardiography (TEE) is crucial to guide the procedure. Bi–dimensional (2D) imaging completed with simultaneous biplane view during surgeon finger pushing on the LV wall (finger test) is currently used to choose the LV access, which is usually on the mid–distal infero–lateral wall (ILW), between the papillary muscles (PMs) at the inferior level of their insertion on LV wall. This simulation helps the operators to evaluate the safe distance to PMs to minimize the risk of damaging the sub–valvular apparatus during the insertion of the device. We aimed to compare a new 3D method with the conventional one in terms of safety and better localization of the desired entry site.

Methods

During the procedure finger test has been performed with conventional 2D imaging and simultaneous biplane method. It has been completed using the real time 3D TEE placing the sample box in the bi–commissural view of the LV including the PMs and the apex. The resulting 3D volume was subsequently edited to visualize the LV from above (surgical view) to localize the bulge of the operator finger pushing on the desired segment of the LV wall. We asked the first operator, the second operator and the cardiac surgery fellow, separately, to evaluate location of their finger pushing, in terms of desired position and safety of access, both with 2D method and the 3D method to estimate the inter–operator concordance.

Results

From March 2019 to September 2021 42 consecutive cases have been performed using finger test completed with 3D method without complications related to the trans–ventricular access. Regarding the choice of the right and safe entry site, the percentage of agreement between operators was higher using LV real time 3D rendering compared to the conventional finger test [82 + 21% Vs 59% + 29%, IC 95%, p: 0,04].

Conclusion

Three–dimensional finger test is easy to perform and decreases inter–operator variability of image interpretation facilitating the surgeons to choose the best entry site in term of anatomical localization and safety.

Single-cell quantitative RT-PCR analysis of Cpt1b and Cpt2 gene expression in mouse antral oocytes and in preimplantation embryos

Fatty acids represent an important energy source for preimplantation embryos. Fatty acids oxidation is correlated with the embryo oxygen consumption which remains relatively constant up to the 8-cell stage, but suddenly increases between the 8-cell and morula stages. The degradation of fatty acids occurs in mitochondria and is catalyzed by several carnitine acyl transferases, including two carnitine palmitoyl transferases, CPT-I and CPT-II. We have carried out a study to determine the relative number of transcripts of Cpt1b and Cpt2 genes encoding for m-CPT-I and CPT-II enzymes, during mouse preimplantation development. Here we show that Cpt1b transcripts are first and temporally detected at the 2-cell stage and reappear at the morula and blastocyst stage. Cpt2 transcripts decrease following fertilization to undetectable levels and are present again later at the morula stage. These results show that transcription of both Cpt1b and Cpt2 is triggered at the morula stage, concomitantly with known increasing profiles of oxygen uptake and fatty acids oxidation. Based on the number of Cpt2 transcripts detected, we could discriminate the presence of two groups of embryos with high and low number of transcripts, from the zygote throughout preimplantation development. To further investigate if the establishment of these two groups of embryos occurs prior to fertilization, we have analyzed the relative number of transcripts of both genes in antral and ovulated MII oocytes. As for preimplantation embryos, MII oocytes show two groups of Cpt2 expression. Antral oocytes, classified according to their chromatin configuration in SN (surrounded nucleolus, in which the nucleolus is surrounded by a rim of Hoechst-positive chromatin) and NSN (not surrounded nucleolus, in which this rim is absent), show three groups with different numbers of Cpt2 transcripts. All NSN oocytes have a number of Cpt2 transcripts doubled compared to that of the group of MII oocytes with high expression. Instead, SN oocytes could be singled out into two groups with high and low numbers of Cpt2 transcripts, similar to those found in MII oocytes. The results of this study point out a correlation between the timing of fatty acids oxidation during preimplantation development and the expression of two genes encoding two enzymes involved in the oxidative pathway. Furthermore, although the biological meaning for the presence of two groups of oocytes/embryos with different levels of Cpt2 transcripts remains unclear, the data obtained suggest a possible correlation between the levels of Cpt2 expression and embryo developmental competence.