C39 ECHOCARDIOGRAPHIC PREDICTORS OF MALIGNANT EVENTS IN ARRHYTHMIC MITRAL VALVE PROLAPSE POPULATION

Background

Bileaflet mitral valve prolapse (bMVP) has been linked to major arrhythmic events and sudden cardiac death (SCD). Solid evidence of consistent predictors of SCD in this setting is still lacking. Echocardiography is the best tool for the analysis of ventricle mechanics and for the correlation with electrical myocardial activation. The aim of this study was to find new predictors of malignant events within an arrhythmic MVP population.

Methods

We conducted a retrospective comparative analysis, selecting 22 patients with bMVP with a high arrhythmic risk profile. 6 of them had a previous major arrhythmic event (5 aborted SCD, one cardiogenic syncope) and previously received ICD implantation (ICD–MVP), while 16 presented with a high arrhythmic burden without major events (A–MVP). All patients underwent transthoracic echocardiography in the last year. Each echocardiogram followed a specific protocol focused on mitral valve anatomy and ventricular contraction using 2D imaging, 3D imaging, tissue doppler imaging and speckle tracking analysis.

Results

ICD–MVP group, compared with A–MVP group, presented a longer anterior leaflet (AML) length (28,6 mm, IQR: 24,1–31,1 mm; vs 21,4 mm, IQR: 20,4–24,0 mm; p = 0,03), larger mitral valve annulus (MVA) indexed area (6,88 cm2/m2, IQR 6,27–7,87 cm2/m2 vs 5,44 cm2/m2, IQR: 4,93–6,15 cm2/m2, p = 0,02), lower MVA anteroposterior diameter/AML length ratio (1,24, IQR: 1,21–1,41 vs 1,50, IQR 1,32–1,62; p = 0,049), higher inferolateral basal S3 velocity (26 cm/s, IQR: 20,8–29,6 cm/s vs 14,2 cm/s, IQR 10,1–21,3 cm/s; p = 0,02) and a greater mechanical dispersion (MD) of the basal and mid–ventricular segments calculated with speckle tracking (128 ms, IQR: 125–131 ms; vs 58 ms, IQR 45–106 ms; p = 0,03). Mitral regurgitation grading, instead, did not correlate with malignant events. Best predictors of malignant events were AML length and MD of basal and mid–ventricular segments. Cut–off values with highest sensibility and specificity above 80% were 26 mm for AML length and 122 ms for MD of basal and mid–ventricular segments. Logistic bivariate regression confirmed AML length as an independent predictor of malignant events (p = 0,01), while MD of basal and mid–ventricular segments showed a trend toward significancy (p = 0,07).

Conclusion

Five parameters were found to be predictors of malignant events in a high–risk MVP population. AML length and MD of the basal and mid–ventricular segments presented the best predictive value.

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.

Pharmacological control of intimal hyperplasia in small diameter polytetrafluoroethylene grafts. An experimental study

OBJECTIVE

The efficacy of a postoperative treatment with Low molecular weight heparin (LMWH) vs Ticlopidine in controlling early thrombosis, intimal hyperplasia and growth of true endothelial cells in small prosthetic expanded polytetrafluoroethylene (ePTFE) grafts (4 mm) interposed in the carotid artery of sheep has been evaluated.

EXPERIMENTAL DESIGN

Thirty animals were randomized into three different groups: control group (CTRL); ticlopidine hydrochloride (TICL) 250 mg/b.d. by month for 4 weeks from day 1; LMWH 3,085 IU AXa s.c. preoperatively and once a day for the same period.

RESULTS

Complete thrombosis of the graft occurred in 7 sheep in the CTRL group and 5 in the TICL group while 2 partial thrombosis were observed in the LMWH group (n.s.). In all the evaluable cases, hyperplasia was observed in both anastomotic areas and did not involve the middle portion of the graft. The mean +/- SD intimal thickness was 603 +/- 20 micron in the CTRL group, 356 +/- 10 in the TICL group and 152 +/- 17 in the LMWH group (p < 0.001) compared to the 60 +/- 12 of the normal intima. True endothlial cells were found mainly in the LMWH group close to the arterial anastomosis.

CONCLUSIONS

The postoperative use of LMWH seems to inhibit intimal hyperplasia, with interesting results also on patency and cellular coverage. Further studies are necessary to support this promising trend.

[Prevention of vascular intimal hyperplasia in small caliber prostheses. Preliminary results]

Intimal hyperplasia is one of the main risk factors for the patency of small diameter bypass grafts. The standard unfractioned heparin (UH) is able to control this phenomenon but the clinical use is not fit for long term treatment; on the other hand the antiplatelet drugs have an anti-thrombotic effect but they seem to be unable to control intimal hyperplasia. Low molecular weight heparins (LMWH) have an anti-thrombotic effect superimposable to that of UH with minimal side-effects and might inhibit intimal hyperplasia too. Based on these criteria, we carried out an experimental study on sheep with the aim of evaluating the efficacy of postoperative treatment with LMWH versus an anti-platelet drug in controlling intimal hyperplasia and growth of true endothelial cells in small prosthetic ePTFE grafts (4 mm) interposed in the carotid artery. At the operation, 30 sheep were randomly located in 3 groups: A = control group, no treatment; B = Ticlopidine hydrochloride 250 mg/bid by mouth for 4 weeks; C = LMWH 3.075 IU AXa (0.3 ml) sc preoperatively and then once a day for the same period. Complete thrombosis of the graft occurred in 7 sheep of group A, 5 in B and 2 partial in group C. The intimal hyperplasia was moderate-severe in group A, mild-moderate in group B and no-mild in group C. True endothelial cells were found mainly in the LMWH group; in the other groups and in other portions of the grafts the cellular coverage was accomplished almost completely by fibroblasts. The study is still in progress with 6 further sheep treated with LMWH.