Methods

This study consisted of 223 consecutive patients with severe symptomatic calcific aortic stenosis at high or prohibitive risk for conventional aortic valve replacement surgery. These patients were subsequently treated with a TAVR procedure from May 2007 through December 2014 with either the CV or the XT through a transfemoral approach. All patients were prospectively evaluated by our institution’s multidisciplinary heart team, which includes several interventional cardiologists, cardiac surgeons, imaging cardiologists, and anesthesiologists who determined the eligibility and appropriateness of each patient. Exclusion criteria included patients with TAVR through a nontransfemoral approach and patients with a failed previous aortic bioprosthesis.

The baseline evaluation included a transthoracic echocardiogram (TTE) for the diagnosis of severe aortic stenosis. AR was categorized on baseline TTE according to the degree of severity grade: none or trace (grade 0), mild or mild to moderate (grade 1), moderate (grade 2), moderate to severe (grade 3), and severe (grade 4). The general severity of AR was defined according to the American Society of Echocardiography (ASE) Guidelines. Furthermore, left- and right-sided cardiac catheterizations were completed including selective coronary angiography to detect significant coronary disease. Annular sizing to determine valve size were completed with 3-dimensional cardiac computed tomographic angiography with expert recommended evaluations and standard postprocessing cardiac and aortoiliac sizing assessments. All patients had either monitored anesthesia care or general anesthesia administered by our cardiac anesthesiologists in our hybrid catheterization laboratories.

All the baseline demographic, laboratory, electrocardiographic, radiographic, imaging, procedural, and postprocedural parameters were prospectively collected and entered into our institutional valve database by a cardiologist at the MedStar Cardiovascular Research Network. Data collection was approved by the local institutional review board.

Our complete cohort included 2 groups of patients who underwent transfemoral TAVR: either a CV device (valve sizes of 23, 26, 29, 31 mm) or an XT device (23, 26, 29 mm). Intraprocedural, prevalve balloon aortic valvuloplasty (pre-BAV) is systematically performed for most of our BE valve cases. In contrast, for the SE valves, pre-BAV is usually performed if the baseline cardiac computed tomographic angiographic study demonstrates a significant burden of calcification and/or fibrosis of the native aortic leaflets. In addition, intraprocedural echocardiographic imaging with either a transesophageal echocardiogram or TTE is performed directly after valve implantation to evaluate valve position and function, degree, quality, and location of AR (either transvalvular or paravalvular) and to rule out complications. For the great majority of cases, the decision to perform additional strategies of follow-up balloon postdilation (BPD) and/or implanting a second prosthesis in a valve-in-valve strategy is dependent on the degree and quality of post-TAVR AR. If the consensus of the primary operators and the echocardiography attending was that there is the presence of AR more than moderate in severity, then the decision was made to pursue additional strategies in an attempt to reduce the AR burden to less than moderate and subsequently reevaluate with an intraprocedural TTE or transesophageal echocardiogram. Of note, the balloon size for the BPD was chosen in accordance to the preceding transcatheter heart valve (THV) implanted for the objective of further expanding the implanted THV to have better apposition to the aortic root and therefore further reduction of PVR. Subsequently, the postprocedural comprehensive TTE assessment (at ≥1 days after the index procedure) is performed to evaluate the cardiac function, valve function, and residual total AR in accordance with the American Society of Echocardiography and the Valve Academic Research Consortium (VARC) 2 guidelines for the evaluation of prosthetic aortic valves. The main echocardiographic parameter that was assessed in this study was the total AR on the inhospital post-TAVR TTE.

Clinical events have all been prospectively adjudicated by a cardiologist who determined the nature of the event. All clinical safety outcomes and complications collected comply with the VARC-2 consensus report definitions during the index hospitalization, including assessment of AR with a predischarge TTE. The primary end point of this study was the rate of inhospital post-TAVR mild-or-greater AR in the CV group versus the XT group, which was assessed by the inhospital post-TAVR TTE and was categorized according to the degree of severity as defined in the American Society of Echocardiography Guidelines. Furthermore, we evaluated the echocardiographic findings at 30-day and 1-year follow-up to assess for residual AR and ascertain changes in the total AR burden compared to the AR grade on the inhospital post-TAVR TTE.

Statistical analyses were completed using the SAS version 9.2 (SAS Institute Inc., Cary, North Carolina) program. Continuous variables with normally distributed variables are presented as mean ± standard deviation. Categorical variables are expressed as percentages. The Student t test was used to compare continuous variables, whereas the chi-square test or Fisher’s exact test was used to compare categorical variables. Given that primary end point was any degree of AR (more than mild) at the time of the inhospital post-TAVR TTE, a univariate logistic regression adjustment model was completed using various clinically relevant baseline covariates to assess for association with this end point. Subsequently, if the p value of the covariates after the univariate logistic regression adjustment model was <0.1, then these covariates were subsequently evaluated with a multivariate logistic regression adjustment analysis to assess for their impact as potential independent correlates for the occurrence of post-TAVR mild-or-greater AR. The results were presented as odds ratios (ORs) with their 95% confidence intervals (CIs) and respective p values. All probabilities are 2 sided, and statistically significant differences were defined as p <0.05.

Results

Overall, a total of n = 223 consecutive patients (53% men, mean age 82 years) from May 2007 through December 2014 who had transfemoral TAVR with either a CV (n = 119) or an XT (n = 104) were evaluated. Baseline clinical characteristics stratified by the type of valve implanted are included in Table 1 . The 2 groups had unadjusted significant baseline differences, including more men in the CV group, older patients in the XT group, more patients with hyperlipidemia in the XT group, higher rates of tobacco smoking in the CV group, higher rates of cancer, greater mean Society of Thoracic Surgeons scores, and higher rates of previous balloon aortic valvuloplasty in the XT group compared to the CV group. These significant baseline differences can be explained by the relative timing and enrollment of patients at relatively higher risk into various nested registries for the Partner II Trial and by the patients at relatively lower risk enrolled into the Pivotal CoreValve Trial at our center. Baseline echocardiographic and cardiac computed tomographic parameters according to the type of valve implanted are included in Table 2 . There were again significant differences between our 2 groups in regards to left ventricular end-diastolic dimensions (LVEDD) and end-systolic dimensions, left atrial dimensions, aortic valve area, and aortic valve gradients and peak velocity ( Table 2 ).

The procedural and inhospital results, including the inhospital post-TAVR TTE, are arranged between the 2 groups in Table 3 . It is important to recognize that there were no statistically significant differences in the rates of any degree of total AR with the CV versus the XT ( Figure 1 ). In addition, there was no evidence of more-than-moderate AR in either group ( Table 3 , Figure 1 ). Furthermore, in regard to the combined incidence of mild-or-greater AR, there was still no statistically significant difference between the CV (77%) and the XT (71%) groups (p = 0.331). Of note, there were significant differences in the rates of intraprocedural BPD with the CV (17%) versus the XT (6%; p = 0.009) and in the rates of intraprocedural implantation of a second prosthesis in a valve-in-valve strategy with the CV (10%) versus the XT (2%; p = 0.036; Table 3 , Figure 2 ). The results demonstrated nonsignificant differences in the moderate-or-greater AR rates with only 3% versus 4% in the CV versus the XT system (p = 0.707; Table 3 ). There is no evidence of any moderate-to-severe or severe AR in either group on the inhospital post-TAVR TTE study during the index hospitalization. In the total cohort (n = 223), the rates of post-TAVR AR included 63% mild AR, 8% mild-to-moderate AR, 4% moderate AR, and 0% for more-than-moderate AR.

Post-TAVR echocardiographic assessment of AR severity. AR severity grades: grade 0 = none or trace, grade 1 = mild or mild to moderate, grade 2 = moderate, grade 3 = moderate to severe, grade 4 = severe.

Rates of intraprocedural strategies to mitigate post-TAVR AR.

Furthermore, the unadjusted inhospital safety outcomes were also evaluated between the 2 groups, and there were no significant differences in the rates of multiple VARC-2 safety ( Table 4 ). However, as expected, a significant difference was found in the rates of inhospital new pacemaker implantation with the CV at 23% versus the XT at 7% (p = 0.001). There was no difference in the unadjusted 30-day all-cause mortality rates with 4% versus 5% with the CV versus the XT valve (p = 0.1000), respectively. However, there was a significant difference in the 1-year unadjusted, all-cause mortality with 10% versus 20% in the CV versus the XT (p = 0.034), respectively. No significant survival outcome conclusions were made given the setting of significantly different baseline characteristics in the 2 groups.

A univariate logistic regression adjustment model was completed using selected, clinically relevant baseline covariates to assess for associations with the primary end point ( Table 5 ). Subsequently, extensive multivariate logistic regression adjustment models were created to test clinically significant baseline covariates as potential independent correlates of the primary end point ( Table 6 ). Consequently, the covariates of age (OR 1.05; p = 0.041; 95% CI 1.01 to 1.11) and baseline LVEDD (OR 1.99; p = 0.031; 95% CI 1.07 to 3.72) were found to be directly associated with the primary end point of post-TAVR mild-or-greater AR. Moderate or severe aortic valve calcification was found to have a trend toward being a significant predictor of the primary end point ( Table 6 ).

Table 5

Univariate logistic regression model of in-hospital mild-or-greater aortic regurgitation

Variable	p-value	Odds ratio	Lower odds ratio	Upper odds ratio
Society of Thoracic Surgeons score	0.190	1.05	0.98	1.13
Moderate-or-severe aortic valve calcification	0.243	1.64	0.71	3.79
Pre-echo left ventricular end diastolic diameter	0.218	1.31	0.85	2.01
Pre-echo left ventricular end systolic diameter	0.460	1.15	0.80	1.65
Pre-echo left ventricular ejection fraction	0.841	1.00	0.98	1.02
Pre-echo ≥moderate aortic regurgitation	0.208	3.81	0.47	30.5
Pre-echo ≥moderate myocardial infarction	0.032	9.28	1.22	70.9
Pre-balloon aortic valvuloplasty performed	0.345	1.47	0.66	3.27
Valve 23mm	0.711	0.87	0.43	1.79
Valve 26mm	0.952	0.98	0.50	1.92
Valve 29mm	0.794	0.91	0.45	1.83
Valve 31mm	0.397	1.51	0.58	3.91
Edwards XT Valve	0.303	0.72	0.38	1.35
CoreValve	0.303	1.39	0.74	2.60
2nd prosthesis (valve-in-valve)	0.336	0.47	0.10	2.19
Balloon post-dilation	0.643	0.81	0.33	1.98
Male gender	0.048	1.90	1.02	3.61
Age	0.206	1.02	0.99	1.06
Chronic kidney disease	0.099	1.80	0.89	3.62
Porcelain aorta	0.895	1.08	0.33	3.52
Hyperlipidemia	0.170	1.71	0.79	3.68
Pre-echo aortic valve area (cm 2 )	0.919	0.88	0.08	10.1
Pre-echo trans-aortic mean pressure gradient (mmHg)	0.643	1.01	0.98	1.04
Native annular diameter by computed tomography	0.562	1.02	0.95	1.11

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