A novel system for the treatment of aortic annular dilation: an ex vivo investigation

Coronary Perfusion After Valve-in-Valve Transcatheter Aortic Valve Implantation in Small Aortic Root: In Vitro Experimental Assessment

Coronary flow obstruction following transcatheter aortic valve-in-valve implantation (VIV-TAVI) is associated with a high mortality risk. The aim of this work was to quantify the coronary perfusion after VIV-TAVI in a high-risk aortic root anatomy. 3D printed models of small aortic root were used to simulate the implantation of a TAVI prosthesis (Portico 23) into surgical prostheses (Trifecta 19 and 21). The aortic root models were tested in a pulsatile in vitro bench setup with a coronary perfusion simulator. The tests were performed at baseline and post-VIV-TAVI procedure in aligned and misaligned commissural configurations under simulated hemodynamic rest and exercise conditions. The experimental design provided highly controllable and repeatable flow and pressure conditions. The left and right coronary mean flow did not differ significantly at pre- and post-VIV-TAVI procedure in any tested configurations. The commissural misalignment did not induce any significant alterations to the coronary flow. High-risk aortic root anatomy did not trigger coronary ostia obstruction or coronary flow alteration after transcatheter aortic valve implantation in a surgical bioprosthesis as shown from in-vitro flow loop tests.

Early results after aortic annuloplasty with a complete external Dacron band

OBJECTIVE

This study evaluates the early results of our initial experience with aortic annuloplasty using a complete external Dacron band in the setting of type Ic or type II aortic regurgitation (AR).

METHODS

From May 2017 to August 2019, 16 patients (88% bicuspid aortic valves, no patients with connective tissue disorders) underwent aortic annuloplasty with an external complete Dacron band. Clinical and echocardiographic follow-up was 100% complete. Clinical and echocardiographic follow-up averaged 24.4 ± 9.3 and  15.1 ±  8.3 months, respectively.

RESULTS

Mean cardiopulmonary and cross-clamp times were 105 ± 15 (72-127) and 86 ± 15 (51-113) min, respectively. Early and late mortality was 0%, with no incidents of endocarditis or cerebrovascular events during the follow-up. Two patients were re-operated during the follow-up, one due recurrent aortic regurgitation (12 months after the first operation) yielding a freedom from reoperation due to AR at 1 year and 3 years of 100% ± 0% and 93.3% ± 5.7%, respectively. Based on the latest echocardiogram, five patients had either none or trivial AR, six had mild AR, and three had mild-to-moderate AR.

CONCLUSIONS

The early clinical and echocardiographic results after using a complete external Dacron band are promising; however, more data and longer follow-up are needed to determine its role in annular management during aortic valve repair.

Geometric changes in the aortic valve annulus during the cardiac cycle: impact on aortic valve repair

OBJECTIVES

The growing experience in aortic valve (AV) repair showed that annular stabilization is a crucial component to achieve stable long-term results after AV repair. Dynamic changes in the AV annulus during the cardiac cycle may have an impact on annuloplasty design.

METHODS

We retrospectively analysed full cardiac cycle multislice computed tomography data from 58 consecutive patients (mean age 75.9 ± 6.5 years, 36% men) with normally functioning tricuspid AVs (normal AV subgroup). The following computed tomography parameters were measured during systole and diastole: maximum, minimum and mean AV annulus diameter, AV annular area and AV annular perimeter. The AV annular eccentricity index was calculated (%) [(max AV annulus × 100/min AV annulus) - 100] in systole and diastole. Subsequently, multislice computed tomography data from 20 patients with severe aortic regurgitation were analysed [aortic valve regurgitation (AR) subgroup].

RESULTS

In the normal AV subgroup, there was a significant decrease in the mean AV annulus diameter from systole to diastole (i.e. 24.6 ± 2.5 mm vs 23.9 ± 2.4 mm, respectively; P < 0.001), which occurred predominantly in the short annular axis (i.e. 21.2 ± 2.4 mm in systole vs 19.9 ± 2.3 mm in diastole; P < 0.001). The mean AV annular area decreased significantly in diastole (i.e. 467.5 ± 94.5 mm2 in systole vs 444.8 ± 86.1 mm2 in diastole; P = 0.012). The annular eccentricity index increased significantly in diastole (33.0 ± 12.2% in systole vs 41.4 ± 13.5% in diastole; P < 0.001). Furthermore, we found an inverse linear correlation between the mean AV annulus diameter and the annular eccentricity index (r = -0.40, P = 0.034). The diastolic annular eccentricity index was significantly reduced in the AR subgroup (i.e. 41.4 ± 13.5% in the normal AV subgroup vs 33.7 ± 14.8% in the AR cohort; P = 0.035).

CONCLUSIONS

The normal AV annulus undergoes important geometric deformation during the cardiac cycle that is significantly reduced in diastole in the AR scenario. A novel AV annuloplasty system should ideally adapt for this marked diastolic annular eccentricity and thereby allow for dynamic aortic root changes during the cardiac cycle.