Transcatheter Aortic Valve Replacement With Different Valve Types in Elliptic Aortic Annuli

Abstract

Background: The aim of this study was to determine the influence of an elliptic annulus on acute device success rates following self-expanding (SE) transcatheter aortic valve replacement (TAVR) vs. balloon-expandable (BE) TAVR.

Methods and Results: Outcomes were assessed using Valve Academic Research Consortium-2 definitions. Aortic annulus ratio (AAR) was measured as short axis diameter/long axis diameter. Mean AAR was 0.81±0.06. Patients were therefore divided into 2 groups: AAR <0.82 and AAR ≥0.82. For circular annuli (AAR ≥0.82; 363 patients), high device success rates were achieved in both valve groups (SE valve, 90.5% vs. BE valve, 95.0%, P=0.14). Conversely, for AAR <0.82 (374 patients), SE valves had lower device success rates than BE valves (82.5% vs. 95.3%, P=0.002). For elliptic annuli, SE-TAVR was an independent predictor of unsuccessful device implantation (OR, 6.34, P<0.001). Nonetheless, increased oversizing of SE valves for elliptic annuli was associated with an exponential rise in device success (threshold ≥17.5%; area under the curve, 0.83) but not for BE-TAVR. Furthermore, optimally oversized SE valves and BE valves had a similarly high device success for elliptic annuli (SE valve, 96.2% vs. BE valve, 95.3%).

Conclusions: For circular annuli, similarly high device success was achieved for the 2 valve types. Conversely, for elliptic annuli, SE valves had a lower device success than BE valves. Device success following optimal oversizing of SE valves, however, was similar to that for BE valves.

Transcatheter aortic valve replacement (TAVR) is a well-established alternative to surgical aortic valve replacement for high-risk patients with aortic valve stenosis.^1–3 Historically, the transcatheter heart valve has been developed with balloon-expandable (BE) or self-expanding (SE) systems. The CHOICE study demonstrated that the use of BE valve resulted in a greater rate of device success than the use of SE valves.⁴ Except for differences in valve design, device success depends on the anatomy of the aortic root (i.e., calcification of aortic-valvular complex, angulation of the aorta) or procedural technique (i.e., degree of oversizing, implantation depth).^5–8 Aortic annulus dimension measurements using 3-D cross-sectional imaging modalities reduces procedural complications.⁹ Although the transcatheter heart valves are designed to expand circularly, the native aortic annulus is often oval in shape.⁹ These different shapes give rise to gaps between the aortic annulus wall and the prosthesis frame. Device success is a well-defined outcome as a composite primary endpoint. Nevertheless, only a few studies have reported the frequency of device success for both prostheses using the Valve Academic Research Consortium (VARC)-2 definitions.^4,10 Therefore, the interaction between the degree of non-circular annuli and device success is not well understood. The aim of this study was to determine the influence of elliptic annulus on acute device success rates following SE valve vs. BE valve implantation, and to evaluate pre-procedural predictors of acute device success for an elliptic annulus.

Methods

Subjects and Procedure

Between January 2013 and January 2016, a total of 796 consecutive patients with symptomatic severe aortic stenosis (aortic valve area <1.0 cm²) were treated with SE or BE valve at the present institution. These patients were prospectively included in the TAVR database. After excluding patients with previous bioprosthesis, aortic annulus measurements using diastolic phase, and patients with poor computed tomography (CT) quality, a total of 737 patients were included in the final analysis of this cohort (Figure 1). Aortic annulus ratio (AAR) was measured by the following method: short axis annulus diameter/long axis annulus diameter (Figure 2). The measurement of annulus dimensions was performed blinded to implanted valve type. Mean annulus ratio was 0.81±0.06. Patients were therefore divided into 2 groups: AAR <0.82 and AAR ≥0.82 (Figure 1). Baseline clinical, echocardiographic, and procedural details for TAVR were recorded for all patients including 1-month clinical assessments during a follow-up visit. TAVR endpoints, device success, and adverse events were considered according to the VARC-2 definitions.¹⁰ Device success was defined according to the following inclusion criteria: absence of procedural mortality, correct positioning of a single prosthetic heart valve into the proper anatomical location, and intended performance of the prosthetic heart valve.¹⁰ Post-procedural paravalvular leak (PVL) was assessed in line with VARC-2 criteria on periprocedural transesophageal echocardiography reviewed retrospectively. As standard procedure, in the case of SE valve implantation, final intraprocedural assessment of PVL on echocardiography was done at least 10 min after implantation. This was performed by one of the physician readers experienced in the assessment of TAVR echocardiograms, blinded to the clinical data. The decision to proceed with TAVR was made on the consensus of a dedicated heart team including experienced clinical and interventional cardiologists and cardiovascular surgeons. The study complies with the Declaration of Helsinki: a locally appointed Ethics Committee approved the research protocol, and informed consent was obtained from all subjects.

Figure 1.

Study flow diagram. Mean aortic annulus ratio (short axis annulus diameter/long axis annulus diameter) was 0.81±0.06. All patients were therefore divided into 2 groups according to aortic annulus ratio (<0.82 or ≥0.82). CT, computed tomography; TAVR, transcatheter aortic valve replacement.

Figure 2.

Aortic annulus shape before transcatheter aortic valve replacement: (Left) non-circular annulus (annulus ratio, 0.67) and (Right) circular annulus (annulus ratio, 0.98).

Multi-Detector CT and Aortic Annulus Analysis

Multi-detector CT was performed using a Siemens Somatom Cardiac 64 or Siemens Somatom Flash scanner (Siemens Medical Solutions USA, Malvern, PA, USA). Image acquisition for the most part was performed with retrospective ECG gating. For aortic root dimensions, curved multiplanar reconstruction analysis was performed using 3-Mensio valves software^TM (version 8.2, Pie Medical Imaging, Maastricht, the Netherlands).⁹ A systolic phase was evaluated.⁹ Oversizing was determined as follows: calculated perimeter oversizing (%)=(valve perimeter/annulus perimeter−1)×100 for SE valves; calculated area oversizing (%)=(valve area/annulus area−1)×100 for BE valves. For SAPIEN XT valve, the nominal area of a fully expanded valve is 4.15 cm² for the 23-mm valve, 5.31 cm² for the 26-mm valve, and 6.61 cm² for the 29-mm valve. For SAPIEN 3, it is 3.28 cm² for the 20-mm valve, 4.09 cm² for the 23-mm valve, 5.19 cm² for the 26-mm valve, and 6.49 cm² for the 29-mm valve. In contrast, for the SE valve (CoreValve/Evolut R), the nominal perimeter of a fully expanded valve is 72.22 mm for the 23-mm valve, 81.64 mm for the 26-mm valve, 91.06 mm for the 29-mm valve, and 97.34 mm for the 31-mm valve. A recently validated 850-HU threshold was used to detect areas of calcium in the region of interest.⁵ All aortic annulus measurements were performed by a dedicated CT core laboratory at Cedars-Sinai Heart Institute before TAVR.

Statistical Analysis

Continuous variables were tested for normality of distribution using Shapiro-Wilk test and reported and analyzed appropriately thereafter. Mann-Whitney U-test was used in cases of abnormal distribution. Categorical variables were compared using chi-squared test or Fisher exact test. Variables that were found to influence unsuccessful device implantation with P<0.05 on univariate analysis were entered into a multivariate logistic regression model to determine the independent predictors of d unsuccessful device implantation. Receiver operating characteristic (ROC) curves were generated using unsuccessful device implantation as the endpoint. Sensitivity and specificity were calculated using specific cut-offs using the Youden index. Significance was set at a 2-tailed P<0.05. SPSS 22.0 (SPSS, Chicago, IL, USA) was used to perform statistical evaluation.

Results

Overall, 796 patients who had cardiac CT underwent CoreValve/Evolut R (Medtronic, Minneapolis, MN, USA) or SAPIEN XT/SAPIEN 3 (Edwards Lifesciences, Irvine, CA, USA) TAVR at the present institute during the study period. A total of 59 patients were excluded from analysis (Figure 1). Of the remaining 737 patients, 374 patients had AAR <0.82 (mean AAR, 0.77±0.04) and 363 had AAR ≥0.82 (mean AAR, 0.87±0.04). Baseline characteristics of the study population are listed in Table 1. The AAR ≥0.82 group had a higher prevalence of chronic obstructive pulmonary disease (Table 1). Other clinical or imaging baseline parameters were similar except for annulus long and short axis diameters (Table 1). Details of the procedural outcome are shown in Table 2. Regardless of AAR, post-dilatation was less frequently performed in BE-TAVR (AAR <0.82, 10.1% vs. 28.1%; AAR ≥0.82, 6.7% vs. 27.0%; P<0.001 for both, respectively). With regard to the need for a second valve, regardless of AAR, the SE valve group had a high incidence of need for second valve implantation compared with the BE valve group (AAR ≥0.82, 6.3% vs. 1.0%, P=0.019; AAR <0.82, 10.5% vs. 1.6%, P=0.002). For patients with SE valve implantation and AAR <0.82, 4 of the 6 patients required a second valve intra-procedurally due to moderate or higher PVL: 2 patients still had moderate PVL after second valve implantation, while 2 patients needed second valve due to high position and valve embolization. For patients with BE valve implantation, 4 of 5 patients received a second valve due to high grade of PVL, and 1 patient due to valve embolization. Conversely, for AAR ≥0.82, in 2 of the 4 patients with SE-TAVR needing a second valve, the reason was significant PVL. In the remaining 2 patients it was due to valve embolization. For patients with BE-TAVR, the need for second valve in 2 of 3 patients was due to high position resulting in significant PVL. In 1 patient it was due to PVL despite adequate height of valve implantation. With regard to PVL, for AAR <0.82, the occurrence of greater than moderate PVL was higher in the SE valve group (7.0% vs. 1.3%, P=0.021) than the BE valve group but not for AAR ≥0.82 (P=0.28).

Table 1. Baseline Clinical Characteristics

	AAR <0.82 (n=374)	AAR ≥0.82 (n=363)	P value
Age (years)	83.0 (77.0–88.0)	83.0 (78.0–88.0)	0.96
Female	151 (40.4)	145 (39.9)	0.11
BSA (m2)	1.84 (1.66–2.02)	1.84 (1.67–2.00)	0.99
Hypertension	346 (92.5)	336 (92.6)	0.98
Dyslipidemia	327 (87.4)	311 (85.7)	0.48
Diabetes	127 (34.0)	104 (28.7)	0.12
COPD	73 (19.5)	101 (27.8)	0.008
CAD	232 (62.0)	210 (57.9)	0.25
Cerebrovascular disease	85 (22.7)	84 (23.1)	0.89
Peripheral artery disease	97 (25.9)	106 (29.2)	0.32
Previous CABG	90 (24.1)	78 (21.5)	0.41
Previous pacemaker	71 (19.0)	61 (16.8)	0.43
eGFR (mL/min)	45.0 (36.3–58.0)	47.4 (38.6–59.5)	0.26
Logistic EURO score (%)	16.2 (10.1–28.4)	16.2 (9.6–29.8)	0.88
AV area (cm2)	0.60 (0.50–0.70)	0.60 (0.50–0.70)	0.92
Ejection fraction (%)	62.0 (48.0–67.0)	60.0 (50.0–66.0)	0.64
AV mean gradient (mmHg)	43.0 (40.0–51.0)	44.0 (40.0–50.0)	0.98
CT annulus long axis diameter (mm)	27.8±2.8	26.4±2.7	<0.001
CT annulus short axis diameter (mm)	21.4±2.3	23.0±2.3	<0.001
CT annulus perimeter (mm)	78.0 (72.7–84.1)	78.4 (72.8–83.7)	0.71
CT annulus area (mm2)	461.0 (404.2–539.8)	478.0 (412.6–541.5)	0.41
CT aortic root angulation (°)	47.1±8.1	47.0±8.7	0.91
AV calcium volume (850 HU) (mm3)	186.1 (79.8–330.8)	162.3 (69.3–314.6)	0.19
LVOT calcification	184 (49.2)	165 (45.5)	0.31

Data given as mean±SD, median (IQR), or n (%). AAR, aortic annulus ratio; AV, aortic valve; BSA, body surface area; CABG, coronary artery bypass graft; CAD, coronary artery disease; COPD, chronic obstructive pulmonary disease; CT, computed tomography; eGFR, estimated glomerular filtration rate; LVOT, left ventricular outflow tract.

Table 2. Procedural Data and Clinical Outcome

	AAR <0.82			AAR ≥0.82
	SE valve (n=57)	BE valve (n=317)	P value	SE valve (n=63)	BE valve (n=300)	P value
Valve type
SAPIEN XT	–	167 (52.7)		–	144 (48.0)
SAPIEN 3	–	150 (47.3)		–	156 (52.0)
CoreValve	49 (86.0)	–		48 (76.2)	–
Evolut R	8 (14.0)	–		15 (23.8)	–
Valve size (mm)			<0.001			<0.001
20	–	4 (1.3)		–	5 (1.7)
23	2 (3.5)	77 (24.3)		2 (3.2)	71 (23.7)
26	16 (28.1)	137 (43.2)		13 (20.6)	125 (41.7)
29	20 (35.1)	99 (31.2)		32 (50.8)	99 (33.0)
31	19 (33.3)	–		16 (25.4)	–
Degree of oversizing (%)	17.3 (12.3–20.0)	12.6 (6.4–21.8)	0.07	16.4 (12.6–19.5)	12.3 (5.3–19.8)	<0.001
Alternative access	2 (3.5)	27 (8.5)	0.15	4 (6.3)	30 (10.0)	0.37
Device success	47 (82.5)	302 (95.3)	0.002	57 (90.5)	285 (95.0)	0.14
Need for second valve	6 (10.5)	5 (1.6)	0.002	4 (6.3)	3 (1.0)	0.019
Valve embolism	1 (1.8)	1 (0.3)	0.28	2 (3.2)	0	0.03
Aortic root injury	0	1 (0.3)	0.85	0	6 (2.0)	0.32
Post-balloon dilatation	16 (28.1)	32 (10.1)	<0.001	17 (27.0)	20 (6.7)	<0.001
Total contrast volume (mL)	114.3±54.3	73.9±37.8	<0.001	97.1±52.0	68.3±31.7	0.001
Periprocedural TEE
Paravalvular leak
None/trivial	30 (52.6)	212 (66.9)	0.038	44 (69.8)	206 (68.7)	0.86
Mild	23 (40.4)	101 (31.9)	0.21	17 (27.0)	90 (30.0)	0.63
Moderate or severe	4 (7.0)	4 (1.3)	0.021	2 (3.2)	4 (1.3)	0.28
Gradient <20 mmHg or peak velocity <3 m/s	56 (98.2)	313 (98.4)	0.63	62 (98.4)	292 (97.3)	0.52
Effective orifice area >1.1 cm2 † (>0.9 cm2)‡	54 (94.7)	313 (98.7)	0.08	61 (96.8)	292 (97.3)	0.54
Mortality	1 (1.8)	6 (1.9)	0.71	0	3	0.54
CVA/TIA	0	5 (1.6)	0.43	0	12 (4.0)	0.10
Myocardial infarction	1 (1.8)	1 (0.3)	0.28	0	2 (0.7)	0.68
New PPMI§	19 (42.2)	38 (14.8)	<0.001	17 (29.8)	26 (10.6)	<0.001
Acute kidney injury stage 3	0	1 (0.3)	0.85	0	2 (0.7)	0.68

Data given as mean±SD, median (IQR), or n (%). ^†BSA ≥1.6 cm²; ^‡BSA <1.6 cm². ^§Patients with history of pacemaker were excluded. BE, balloon-expandable; CVA, cerebrovascular accident; PPMI, permanent pacemaker implantation; SE, self-expanding; TEE, transesophageal echocardiography; TIA, transient ischemic attack. Other abbreviations as in Table 1.

Overall, device success rate was 86.7% for SE valve implantation and 94.7% for BE valve implantation. Although similar device success was achieved in both valve groups for AAR ≥0.82 (device success: SE valve, 90.5% vs. BE valve, 95.0%, P=0.14), for elliptic annuli (AAR <0.82), device success was significantly lower in the SE valve group than the BE valve group (82.5% vs. 95.3%, P=0.002). Ten out of 57 patients with SE valve and elliptic annuli had unsuccessful device implantation. The reasons included need for a second valve in 6 cases, moderate-severe PVL in 2 cases, increased gradient and less effective orifice area in 1 case, and death in 1 case. Moreover, after subdividing the BE valve group according to device design, for AAR <0.82 the SAPIEN XT valve achieved a higher device success rate than the SE valves (93.4% vs. 82.5%; P=0.014). In contrast, SAPIEN XT and SE valves had similar rates of device success for AAR ≥0.82 (SAPIEN XT valve, 94.4% vs. SE valve, 90.5%, P=0.22). Similar device analysis was also performed for each valve design. Device success for SAPIEN XT was 94.4% vs. 94.0% for circular and elliptical annulus, respectively (P=0.87). Device success for SAPIEN 3 device was 95.5% vs. 96.7% for circular and elliptic annuli, respectively (P=0.60). Device success for CoreValve device was 89.6% vs. 83.3% for circular and elliptical annulus, respectively (P=0.37).

With regard to BE-TAVR, the AAR ≥0.82 group had a higher tendency to aortic root injury compared with the AAR <0.82 group (2.0% vs. 0.3%, P=0.053), but degree of oversizing, frequency of left ventricular outflow tract (LVOT) calcium, leaflet calcium, sinus of Valsalva diameter, and incidence of post-dilatation were similar between the 2 groups (P=NS for all). For new permanent pacemaker implantation (PPMI), regardless of AAR, the incidence of PPMI was higher in patients with SE-TAVR than BE-TAVR (P<0.001 for both; Table 2). Furthermore, patients with elliptic annuli and SE-TAVR had a high rate of PPMI (42.2%). This was evident even in patients with BE valve implantation and an elliptic annulus (14.8%; Table 2). Other major complications at 30 days were similar between the 2 valve groups (Table 2).

Independent Predictors of Device Success

For AAR <0.82, variables significant for prediction of unsuccessful device implantation were entered into a multivariable logistic regression model. Independent predictors of unsuccessful device implantation included SE valve (OR, 6.34; 95% CI: 2.44–16.50, P<0.001), degree of oversizing (OR, 0.94; 95% CI: 0.90–0.99, P=0.024), and aortic valve calcium volume (OR, 1.002; 95% CI: 1.001–1.003, P=0.010; Table 3). Successful valve implantation rates according to % oversizing for AAR<0.82 are shown in Figure 3. On ROC curve analysis for prediction of unsuccessful valve implantation in patients with AAR <0.82, the degree of oversizing for BE valve did not predict unsuccessful valve implantation rate (area under the curve [AUC], 0.59, P=0.23). Conversely, for SE valves, an oversizing of 12.7% was identified as the best threshold (AUC, 0.83; 95% CI: 0.70–0.96, P<0.001; sensitivity, 53.2%; specificity, 90.0%). Overall, 47.4% (n=27) of the patients had oversizing >17.5%. Increased oversizing was associated with an exponential rise in device success for the SE valves, ranging from only 50.0% (<10% oversizing) to 100% (>20% oversizing; Figure 3). If there was a larger oversizing (≥17.5% oversizing), significantly higher SE valve success was achieved (Figure 4). Therefore, for AAR<0.82, optimally oversized SE valves and BE valves had a similarly high rate of device success (SE valve, 96.2% vs. BE valve, 95.3%).

Table 3. Independent Predictors of Unsuccessful Device Implantation for Elliptic Annulus (AAR <0.82)

	Univariate OR (95% CI)	P value	Multivariate OR† (95% CI)	P value
SE valve	4.28 (1.82–10.1)	0.002	6.34 (2.44–16.5)	<0.001
AV calcium volume	1.002 (1.001–1.003)	<0.001	1.002 (1.001–1.003)	0.010
% oversizing	0.95 (0.91–0.98)	0.006	0.94 (0.90–0.99)	0.024

^†Parameters for prediction (P<0.05) were entered into a multivariable logistic regression model. Abbreviations as in Tables 1,2.

Figure 3.

Device success rate according to % oversizing in patients with elliptic annulus. (A) Self-expanding valve implantation success rate increases exponentially as oversizing increases. (B) Conversely, balloon-expandable valves had little change in device success rate.

Figure 4.

Device success rate for elliptic annulus: optimally oversized self-expanding (SE) valve had a high success rate, similar to that for the balloon-expandable (BE) valve. On receiver operating characteristic curve analysis for prediction of SE valve implantation success for elliptic annulus, 17.5% oversizing (area under the curve, 0.83; sensitivity, 53.2%; specificity, 90.0%) was identified as the best threshold, and SE valve in patients with elliptic annulus were then divided into 2 groups based on this threshold. Optimally oversized SE valve had a high device success rate.

Discussion

The aim of this study was to determine the influence of elliptic annulus on acute device success rates following SE valve vs. BE valve implantation. The findings can be summarized as follows: (1) for circular annuli (AAR ≥0.82), high device success was achieved in both valve groups (SE valve, 90.5% vs. BE valve, 95.0%); (2) in contrast, for elliptic annuli (AAR <0.82), SE valves had a lower rate of device success than BE valves (82.5% vs. 95.3%); and (3) for elliptic annuli, SE-TAVR was an independent predictor of unsuccessful device implantation, but device success rate after SE-TAVR, however, was similar to that after BE-TAVR with optimal oversizing of perimeter >17.5%. For BE-TAVR, the circular annulus group had a higher tendency to aortic root injury than the non-circular group, but there were no differences in predictors identified by prior studies between the groups, such as LVOT calcification, degree of oversizing, and incidence of post-dilatation.¹¹ Annulus shape might affect aortic root injury following BE valve implantation. For circular annuli, when the balloon is inflated, the BE valve frame can directly compress more forcefully the annulus wall compared with elliptic annuli because there are more interaction points between the frame and the annulus. Therefore, when large oversizing or increased LVOT calcium is present, risk of annulus injury may be increased. This hypothesis should be confirmed in future studies.

Various studies have reported that use of BE valves resulted in a greater rate of device success, lower rates of PVL, lower need for post-dilatation, and lower PPMI compared with SE valves.^4,12,13 Device success is a well-defined outcome endpoint following TAVR. Nevertheless, only a few studies have reported the frequency of device success for both prostheses using the VARC-2 definitions.^4,10 Furthermore, the 2 types of valves have never been directly compared with regard to anatomic or procedural factors that may contribute to different device success rates. A recently published US CoreValve trial reported that acute device success was 86.8%.¹⁴ Overall, in the present study, device success for SE valves (86.7%) was similar to that reported in the US CoreValve trial, and device success for BE valves (94.7%) also was similar to previous studies.^4,12 Furthermore, we divided the patients into circular annulus (AAR ≥0.82) and elliptic annulus (AAR <0.82) groups and assessed the influence of geometric annulus on acute device success following SE valve vs. BE valve implantation. For circular annuli, there was no significant difference in device success rates between the 2 valve groups. In contrast, for an elliptic annulus, SE valves had a combination of higher rates of moderate-severe PVL and higher frequency of need for a second valve – resulting in lower device success rates, especially for patients with moderate-severe PVL. Therefore, eccentric annuli were strongly associated with unsuccessful SE valve implantation, but this was not the case for BE valve implantation.

There are several possible explanations for the present findings. During valve deployment, radial forces affect elliptic aortic annulus shape. Previous studies have shown that the geometry of the annulus changes from a more oval shape before implantation to a more circular shape after implantation.^15,16 Schuhbaeck et al showed that implantation of the bioprosthetic valve reduced the eccentricity of the aortic annulus for both BE and SE devices,¹⁷ but that change in eccentricity was significantly higher for the BE valve compared with the SE valve.¹⁷ Accordingly, for elliptic annuli there may be an increased space that remains between the aortic annulus wall and the SE valve frame compared with BE valve implantations. Moreover, although the prosthesis is designed to expand into a circular shape, the SE prosthesis still may have a non-circular prosthesis configuration after implantation,^17,18 unlike SAPIEN XT or SAPIEN 3 valves.¹⁹ Additionally, non-circularity may theoretically lead to premature degeneration due to asymmetric mechanical strain and this may contribute to PVL or need for a second valve. Nonetheless, further studies are needed to determine the validity of this hypothesis.

In a logistic regression model, other significant predictors for unsuccessful device implantation for elliptic annuli included oversizing and aortic valve calcium volume. Severe aortic valve calcification and oversizing were shown to be an independent predictor of PVL after SE- and BE-TAVR in prior studies.^5,7,20

In the present study, use of SE valve for elliptic annuli resulted in lower device success rates, but increased oversizing of SE valves resulted in higher device success rates, whereas the degree of BE valve oversizing had little effect on device success rate (Figure 3). On ROC curve analysis, lower oversizing of SE valves for elliptic annulus predicted unsuccessful device implantation. Importantly, optimally oversized SE valves (≥17.5%) had a high device success rate (96.2%; Figure 4). It is now accepted that SE valves need more excessive oversizing than BE valves in order to prevent PVL.^4,7,12 Because aortic annuli have an elliptic shape,⁹ the present findings may support the results of those studies. Oversizing of SE valve was especially important in the presence of elliptic annulus. Importantly, device success rate with optimally oversized SE valve was similar to that with BE valve (SE valve, 96.2% vs. BE valve, 95.3%).

Several limitations of the present study should be addressed. This was a retrospective, single-center study. The findings are subject to selection bias and confounders, and the number of patients in both groups was not balanced. For SE-TAVR, longer time is needed to seal gaps creating PVL. It is therefore possible that intra-procedural transesophageal echocardiography may have overestimated the rate of residual PVL in both elliptical and non-elliptical annulus implantations. The relatively low number of events (25 unsuccessful device implantations) mandated a method of multivariable analysis that may exclude relevant variables with a weaker predictive value. Future multicenter studies with a larger number of patients and longer follow-up may further clarify this subject.

Conclusions

For circular annuli, SE- and BE-TAVR had similar rates of device success. For elliptic annuli, SE-TAVR had a lower device success rate compared with BE-TAVR, if oversizing was suboptimal. A similarly high device success rate was achieved, however, if the SE valve was optimally oversized. Higher oversizing appears to be important in mitigating device success for SE-TAVR and this is especially significant for patients with non-modifiable risk factors such as elliptic annuli.

Disclosures

S.R. is a proctor for Edwards Lifesciences. H.J. is a consultant for Edwards Lifesciences, St. Jude Medical, and Venus MedTech. R.R.M. has received grant support from Edwards Lifesciences (Irvine, CA, USA) and St. Jude Medical (St. Paul, MN, USA); and is a consultant for Abbott Vascular, Cordis, and Medtronic; and holds equity in Entourage Medical. All other authors declare no conflicts of interest.

References

• 1.   Makkar RR, Fontana GP, Jilaihawi H, Kapadia S, Pichard AD, Douglas PS, et al. Transcatheter aortic-valve replacement for inoperable severe aortic stenosis. N Engl J Med 2012; 366: 1696–1704.
• 2.   Kodali SK, Williams MR, Smith CR, Svensson LG, Webb JG, Makkar RR, et al. Two-year outcomes after transcatheter or surgical aortic-valve replacement. N Engl J Med 2012; 366: 1686–1695.
• 3.   Adams DH, Popma JJ, Reardon MJ, Yakubov SJ, Coselli JS, Deeb GM, et al. Transcatheter aortic-valve replacement with a self-expanding prosthesis. N Engl J Med 2014; 370: 1790–1808.
• 4.   Abdel-Wahab M, Mehilli J, Frerker C, Neumann FJ, Kurz T, Tölg R, et al. Comparison of balloon-expandable vs self-expandable valves in patients undergoing transcatheter aortic valve replacement: The CHOICE randomized clinical trial. JAMA 2014; 311: 1503–1514.
• 5.   Jilaihawi H, Makkar RR, Kashif M, Okuyama K, Chakravarty T, Shiota T, et al. A revised methodology for aortic-valvar complex calcium quantification for transcatheter aortic valve implantation. Eur Heart J Cardiovasc Imaging 2014; 15: 1324–1332.
• 6.   Sherif MA, Abdel-Wahab M, Stöcker B, Geist V, Richardt D, Tölg R, et al. Anatomic and procedural predictors of paravalvular aortic regurgitation after implantation of the Medtronic CoreValve bioprosthesis. J Am Coll Cardiol 2010; 56: 1623–1629.
• 7.   Dvir D, Webb JG, Piazza N, Blanke P, Barbanti M, Bleiziffer S, et al. Multicenter evaluation of transcatheter aortic valve replacement using either SAPIEN XT or CoreValve: Degree of device oversizing by computed-tomography and clinical outcomes. Catheter Cardiovasc Interv 2015; 86: 508–515.
• 8.   Binder RK, Webb JG, Toggweiler S, Freeman M, Barbanti M, Willson AB, et al. Impact of post-implant SAPIEN XT geometry and position on conduction disturbances, hemodynamic performance, and paravalvular regurgitation. JACC Cardiovasc Interv 2013; 6: 462–468.
• 9.   Jilaihawi H, Kashif M, Fontana G, Furugen A, Shiota T, Friede G, et al. Cross-sectional computed tomographic assessment improves accuracy of aortic annular sizing for transcatheter aortic valve replacement and reduces the incidence of paravalvular aortic regurgitation. J Am Coll Cardiol 2012; 59: 1275–1286.
• 10.   Kappetein AP, Head SJ, Généreux P, Piazza N, van Mieghem NM, Blackstone EH, et al. Updated standardized endpoint definitions for transcatheter aortic valve implantation: The Valve Academic Research Consortium-2 consensus document. J Am Coll Cardiol 2012; 60: 1438–1454.
• 11.   Barbanti M, Yang TH, Rodès Cabau J, Tamburino C, Wood DA, Jilaihawi H, et al. Anatomical and procedural features associated with aortic root rupture during balloon-expandable transcatheter aortic valve replacement. Circulation 2013; 128: 244–253.
• 12.   Abdel-Wahab M, Comberg T, Büttner HJ, El-Mawardy M, Chatani K, Gick M, et al. Aortic regurgitation after transcatheter aortic valve implantation with balloon- and self-expandable prostheses: A pooled analysis from a 2-center experience. JACC Cardiovasc Interv 2014; 7: 284–292.
• 13.   Moat NE, Ludman P, de Belder MA, Bridgewater B, Cunningham AD, Young CP, et al. Long-term outcomes after transcatheter aortic valve implantation in high-risk patients with severe aortic stenosis: The U.K. TAVI (United Kingdom Transcatheter Aortic Valve Implantation) Registry. J Am Coll Cardiol 2011; 58: 2130–2138.
• 14.   Popma JJ, Reardon MJ, Yakubov SJ, Hermiller JB, Harrison JK, Gleason TG, et al. Safety and efficacy of self-expanding TAVR in patients with aortoventricular angulation. JACC Cardiovasc Imaging 2016; 9: 973–981.
• 15.   Willson AB, Webb JG, Gurvitch R, Wood DA, Toggweiler S, Binder R, et al. Structural integrity of balloon-expandable stents after transcatheter aortic valve replacement: Assessment by multidetector computed tomography. JACC Cardiovasc Interv 2012; 5: 525–532.
• 16.   Delgado V, Ng ACT, van de Veire NR, van der Kley F, Schuijf JD, Tops LF, et al. Transcatheter aortic valve implantation: Role of multi-detector row computed tomography to evaluate prosthesis positioning and deployment in relation to valve function. Eur Heart J 2010; 31: 1114–1123.
• 17.   Schuhbaeck A, Weingartner C, Arnold M, Schmid J, Pflederer T, Marwan M, et al. Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses. Eur J Radiol 2015; 84: 1242–1248.
• 18.   Schultz CJ, Weustink A, Piazza N, Otten A, Mollet N, Krestin G, et al. Geometry and degree of apposition of the CoreValve ReValving system with multislice computed tomography after implantation in patients with aortic stenosis. J Am Coll Cardiol 2009; 54: 911–918.
• 19.   Kazuno Y, Maeno Y, Kawamori H, Takahashi N, Abramowitz Y, Babak H, et al. Comparison of SAPIEN 3 and SAPIEN XT transcatheter heart valve stent-frame expansion: Evaluation using multi-slice computed tomography. Eur Heart J Cardiovasc Imaging 2016; 17: 1054–1062.
• 20.   John D, Buellesfeld L, Yuecel S, Mueller R, Latsios G, Beucher H, et al. Correlation of device landing zone calcification and acute procedural success in patients undergoing transcatheter aortic valve implantations with the self-expanding CoreValve prosthesis. JACC Cardiovasc Interv 2010; 3: 233–243.