Neo-Commissural Alignment by Withdrawing and Readvancing the Delivery System during Transcatheter Aortic Valve Replacement with Self-Expanding Prosthesis

Objective To investigate the feasibility of obtaining neo-commissural alignment by withdrawing and readvancing the delivery system during transcatheter aortic valve replacement (TAVR) with self-expanding prosthesis. Methods TAVR was performed in five patients with severe aortic valve stenosis by the femoral approach. The delivery catheter was withdrawn and readvanced with the opposite orientation when the Venus-A plus transcatheter heart valve (THV) centre marker was found to be overlapped with or close to the left marker at the aortic annulus level on the fluoroscopic image at the projection of the right and left coronary cusps superimposing. Neo-commissural alignment was evaluated by comparing the aortic computed tomography before TAVR with it after TAVR. Results The THV centre marker was overlapped with or close to the right marker at the aortic annulus level on the fluoroscopic image at the projection of the right and left coronary cusps superimposed in all the present five patients after withdrawing and readvancing the delivery system. The commissural angle deviation before vs. post TAVR was 12.3° ± 7.0°. Three of five patients had neo-commissural alignment. Two of the five patients had mild neo-commissural misalignment. Conclusions It is possible to obtain the neo-commissural alignment by controlling delivery catheter insertion orientation using the markers on the inflow of the Venus-A plus valve.


Introduction
If percutaneous coronary intervention is required after transcatheter aortic valve replacement (TAVR), coronary access will be more challenging when transcatheter heart valves (THVs) commissural posts face a coronary orifce, particularly with self-expanding valves [1].Venus-A plus THV (Venus Medtech Inc, Hangzhou, China) has three infow markers that are in alignment with the nadirs of THV sinuses (Figure 1) [2,3].Our previous study showed that neo-commissural alignment could be evaluated by observing the three markers of the Venus-A plus THV (3).However, it is not known whether neo-commissural alignment can be obtained by controlling the delivery system.We present a series of cases in which we obtained neo-commissural alignment by manipulating the delivery catheter insertion orientation relative to the three markers of the Venus-A plus THV [4].

Patient Population and Delivery System Management.
TAVR was performed in fve patients with severe tricuspid or type 1 bicuspid aortic valve stenosis by the femoral approach [5].Te delivery catheter carrying the Venus-A plus THV was inserted into the femoral sheath with the fushing port at 9 o'clock, according to the delivery system manual.Te THV centre marker was found to be overlapped with or close to the left marker at the aortic annulus level on the fuoroscopic image in the projection of the right and left coronary cusps superimposed at the frst advancing of the delivery system in these fve patients.Te delivery catheter was withdrawn until the THV reached the descending aorta.Te fushing port was positioned at 3 o'clock by rotating the delivery catheter 180 °.Te THV was then readvanced to the aortic annulus (Figure 2).Given that this was a pilot imaging study, our study was approved by the respective institutional review boards, and the requirement to obtain patient consent was waived.
Figure 2: Te procedure of withdrawing the delivery system to the descending aorta and readvancing the transcatheter heart valve to the aortic annulus was shown from panel a to panel i from case 1.
2 Journal of Interventional Cardiology

Neo-Commissural Alignment Evaluation and Defnition.
Neo-commissural alignment was evaluated by comparing the aortic root computed tomography (CT) of 75% phase before TAVR with it after TAVR.Te FluoroCT software developed by Pascal Tériault-Lauzier and Nicolo Piazza was used for CT analysis.Neo-commissural alignment was defned when the commissural angle deviation was 0 °to 15 °; mild, moderate, or severe neocommissural misalignments were defned when the angle deviation was 15.1 °to 30 °, 30.1 °to 45 °, or 45.1 °to 60 °, respectively [6].

Statistical Analysis.
Variables were presented as the mean ± standard deviation.

Baseline Patient Characteristics.
Te classifcation system from Sievers and Schmidtke was used for describing the aortic valve in our study [5].Baseline patient characteristics are shown in Table 1.

TAVR Procedure and Complications and CT Images.
Te centre marker of THV was overlapped or close with the right marker at the aortic annulus on the fuoroscopic image at the projection of the right and left coronary cusps superimposing after the delivery system was withdrawn to the descending aorta and readvanced in all fve cases without complications including cerebral infarction or vascular injury.Details are shown in Figure 3.

Commissural Angle Deviation before vs. post TAVR.
Te commissural angle deviation before vs. post TAVR was 12.3 °± 7.0 °.Tree of 5 patients had neo-commissural alignment.Two of 5 had mild neo-commissural misalignment (Table 2).Te example of obtaining the angle deviation is shown in Figure 4 from case 5.

Discussion
THV should be deployed with neo-commissural alignment in order to minimize difculties for future coronary access.Te markers on the infow of the 26 mm or 29 mm Venus series THV are in alignment with the nadirs of the THV sinuses.So it is possible to determine the positional relationship of the THV sinuses relative to the native coronary sinuses.Te Venus-A plus THV is retrievable, but the delivery system is more infexible than the frst-generation Venus which cannot be retrieved.Te Venus-A plus delivery catheter can't be rotated when the THV is at the aortic valve annulus.In addition, the delivery catheter only can be bent toward or away from the fushing port (Figure 5).
Deploying the self-expanding THV using a projection in which the right and left coronary cusps overlap has been a standard step during TAVR [8].Te aortic annulus and the infow plane of the THV can be seen simultaneously, and the depth of THV implantation can be determined accurately in this projection.Furthermore, the noncoronary cusp will be isolated in this projection.Te delivery catheter carrying the Venus-A plus valve will rotate by itself while being advanced from the femoral sheath to the aortic valve annulus clockwise or counter-clockwise by some degrees, which is different from one patient to another patient.Te three markers on the THV will be distributed in three situations when the THV is advanced to the aortic annulus in the projection of the right and left coronary cusps overlapping.Tey are the three markers being separated averagely, with the centre marker being close to or overlapped with the left one or close to or overlapped with the right one.Te relationships between the neo-commissure of the THV and the native commissure during the valve deployment are demonstrated in Figure 6.So, in our practice, we used the following strategy to deploy the Venus-A plus THV.In the projection with the right and left coronary cusps overlapping, we will deploy the THV directly if three markers are separated averagely or the centre marker is closed to or overlapped with the right one on the fuoroscopic image when the THV is at the aortic annulus.If the centre marker is closed to or overlapped with the left one on the fuoroscopic image, we will withdraw the delivery system to the descending aorta and rotate the delivery system 180 °, then readvance the THV to the aortic annulus.Te neocommissural alignment or mild commissural misalignment was obtained in all fve cases present in our study, although the THV rotated in the deploying phase by some degrees [2].Te Venus series valve is the frst self-expanding valve which has three radiopaque markers providing a reference for deployment depth and commissure location.Recently, Evolut FX (Medtronic), the newest self-expanding valve in the Evolut series, is added three radiopaque golden markers in the valve infow which are almost exact alignment with the THV commissures [9].So the experience from the Venus-A plus valve mentioned in our study may be referred in the Evolut FX.

Limitations
Te study sample is too small to allow for optimal statistical power.Te possibilities of increasing the cerebral infarction risk are unknown because of the increased number of times that the THV crosses the aortic valve and because of the longer procedure time.

Conclusions
It is possible to obtain the neo-commissural alignment by controlling delivery catheter insertion orientation using the markers on the infow of the Venus-A plus valve.

Figure 1 :
Figure 1: (a) Tree markers (red circles) on the infow of the THV are in alignment with the nadirs of the THV's sinuses (yellow circles).Te circles with dotted lines indicate that they are at the back of the THV.(b) Te markers can be seen under an X-ray (white arrows).THV � transcatheter heart valve.

Figure 3 :
Figure 3: Neo-commissure alignment by manipulating the delivery system.Column 1: angiograms when the THV crossed the aortic annulus at the frst time.Te centre markers were close to or overlapped with the left markers.Column 2: angiograms after the delivery system were withdrawn to the descending aorta and readvanced to the aortic annulus.Te centre markers were close to or overlapped with the right markers.Column 3: angiograms after the THV were deployed.Column 4: transverse aortic sinus CT images before TAVR.Column 5: transverse aortic sinus CT images after TAVR.THV � transcatheter heart valve; CT � computed tomography; TAVR �transcatheter aortic valve replacement; RAO � right anterior oblique; LAO � left anterior oblique; CAU � caudal; and LCA � left coronary artery.

Table 2 :
Commissural angle of deviation before vs. post TAVR.