Author + information
- Received January 26, 2016
- Revision received February 8, 2016
- Accepted February 8, 2016
- Published online April 19, 2016.
- Evaldas Girdauskas, MD, PhDa,∗ (, )
- Mina Rouman, MDb,
- Kushtrim Disha, MDb,
- Beatrix Fey, MDc,
- Georg Dubslaff, MDc,
- Bernhard Theis, MDd,
- Iver Petersen, MD, PhDd,
- Matthias Gutberlet, MD, PhDe,
- Michael A. Borger, MD, PhDf and
- Thomas Kuntze, MDb
- aDepartment of Cardiovascular Surgery, University Heart Center, Hamburg, Germany
- bDepartment of Cardiac Surgery, Central Hospital, Bad Berka, Germany
- cDepartment of Radiology, Central Hospital, Bad Berka, Germany
- dInstitute of Pathology, Friedrich-Schiller University, Jena, Germany
- eDepartment of Radiology, Heart Center, Leipzig, Germany
- fColumbia University Medical Center, New York, New York
- ↵∗Reprint requests and correspondence:
Dr. Evaldas Girdauskas, Department of Cardiovascular Surgery, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany.
Background The correlation between bicuspid aortic valve (BAV) disease and aortopathy is not fully defined.
Objectives This study aimed to prospectively analyze the correlation between functional parameters of the aortic root and expression of aortopathy in patients undergoing surgery for BAV versus tricuspid aortic valve (TAV) stenosis.
Methods From January 1, 2012 through December 31, 2014, 190 consecutive patients (63 ± 8 years, 67% male) underwent aortic valve replacement ± proximal aortic surgery for BAV stenosis (n = 137, BAV group) and TAV stenosis (n = 53, TAV group). All patients underwent pre-operative cardiac magnetic resonance imaging to evaluate morphological/functional parameters of the aortic root. Aortic tissue was sampled during surgery on the basis of the location of eccentric blood flow contact with the aortic wall, as determined by cardiac magnetic resonance (i.e., jet sample and control sample). Aortic wall lesions were graded using a histological sum score (0 to 21).
Results The largest cross-sectional aortic diameters were at the mid-ascending level in both groups and were larger in BAV patients (40.2 ± 7.2 mm vs. 36.6 ± 3.3 mm, respectively, p < 0.001). The histological sum score was 2.9 ± 1.4 in the BAV group versus 3.4 ± 2.6 in the TAV group (p = 0.4). The correlation was linear and comparable between the maximum indexed aortic diameter and the angle between the left ventricular outflow axis and aortic root (left ventricle/aorta angle) in both groups (BAV group: r = 0.6, p < 0.001 vs. TAV group r = 0.45, p = 0.03, z = 1.26, p = 0.2). Logistic regression identified the left ventricle/aorta angle as an indicator of indexed aortic diameter >22 mm/m2 (odds ratio: 1.2; p < 0.001).
Conclusions Comparable correlation patterns between functional aortic root parameters and expression of aortopathy are found in patients with BAV versus TAV stenosis.
The concept of heterogeneity in bicuspid aortic valve (BAV) disease with markedly different forms of BAV-associated aortopathy has gained increasing acceptance in the last few years (1–3). Several classification systems have been introduced to stratify BAV patients on the basis of valve morphotype (4), phenotype of the proximal aorta (5), or a combination of both factors (1). Despite accumulating evidence on pathogenetically different forms of BAV disease, recommendations for the treatment of BAV-associated aortopathy do not currently take this information into account (6,7).
Recent cardiovascular magnetic resonance (CMR) imaging studies provided some insight into rheological mechanisms potentially involved in the development of BAV-associated aortopathy (8,9). Moreover, these imaging studies consistently demonstrate that mid-ascending aortic dilation phenotype is the most common form of BAV-associated aortopathy (8,10). Previous surgical data indicate a strong correlation between presence of BAV stenosis and the development of mid-ascending aortic dilation (11,12). Mid-ascending aortic dilation in patients with tricuspid aortic valve (TAV) stenosis is generally accepted to be a purely hemodynamic “post-stenotic” form of TAV-associated aortopathy (13,14). On the basis of these associations and our previous observations (15), we hypothesized that the expression/severity of aortic valve stenosis–associated aortopathy is a function of transvalvular rheological disturbances and that these are comparable in patients with BAV versus TAV stenosis. We therefore aimed to prospectively analyze the associations between morphological/functional parameters of the aortic root and the expression/severity of aortopathy in patients undergoing surgery for BAV versus TAV stenosis.
We prospectively evaluated all patients who were ≤70 years and underwent aortic valve replacement (AVR) with or without concomitant proximal aortic replacement for aortic stenosis at a single institution (Central Hospital, Bad Berka, Germany) from January 1, 2012 through December 31, 2014. BAV patients with pure or predominant aortic regurgitation were excluded because several recent studies suggested that a pattern of aortopathy may be more influenced by congenital factors in these patients (3,16,17).
A total of 1,526 patients underwent aortic valve surgery at our institution between January 2012 and December 2014. Patients older than 70 years of age (n = 915) were excluded in order to obtain similar risk profiles between BAV and TAV patients. Other exclusion criteria included patients requiring concomitant procedures (other than replacement of the proximal aorta) (n = 201), patients undergoing urgent or emergent surgery (n = 85), reoperations (n = 57), and patients with contraindications for pre-operative CMR (n = 10). All patients with isolated or predominant (i.e., moderate or more) aortic valve insufficiency were also excluded (n = 68). A total of 190 consecutive patients were therefore included in our study. All of these patients (63 ± 8 years of age, 67% male) underwent elective AVR with or without simultaneous proximal aortic surgery for BAV stenosis (n = 137, BAV group) and TAV stenosis (n = 53, TAV group) during the study period and served as a focus of the current study. Our local institutional review board approved the study and all patients gave written informed consent.
The primary endpoint of our study was the relationship between functional/rheological aortic root parameters and the expression/severity of aortopathy (i.e., proximal aortic phenotype, indexed aortic diameter, and histological sum score).
Definitions and measurements
Pre-operative echocardiography and CMR imaging were used to assess the morphology and function of the aortic valve in all patients. BAV was suspected if 2-dimensional short-axis imaging of the aortic valve demonstrated the existence of only 2 commissures delimiting 2 aortic valve cusps. The final decision regarding the bicuspidality versus tricuspidality of the aortic valve was made on the basis of the intraoperative description of valve morphology by the surgeon. Aortic valve stenosis was defined using the published echocardiography guidelines (18).
The maximal cross-sectional diameters of the proximal aorta at the level of aortic annulus, sinuses of Valsalva, sinotubular junction, mid-ascending aorta, and aortic arch were measured pre-operatively by CMR. All aortic diameters were measured as the largest observed cross-sectional diameter perpendicular to the aortic axis in a mid-vessel slice at end-diastole using the inner edge to inner edge technique, in accordance with previously published recommendations for CMR measurements (19). Similar to previous studies (20), we defined the length of the proximal aorta (i.e., longitudinal aortic expansion) as the distance (mm) from the level of aortic annulus to the origin of brachiocephalic trunk (Figure 1A). Moreover, the area of the proximal aorta (cm2) was determined in the most central oblique sagittal plane at end-diastole from the level of the aortic annulus to the origin of brachiocephalic trunk (Figure 1B) (21).
Proximal aortic phenotype was determined on the basis of CMR (Figures 2A to 2D). Normal aorta phenotype was characterized by all cross-sectional aortic diameters <22 mm/m2 of body surface area and nonindexed aortic diameters <40 mm (Figure 2A). Aortic root dilation was defined as maximal aortic dilation at the level of the sinuses of Valsalva, exceeding 22 mm/m2 or 40 mm in maximal diameter (Figure 2B). Mid-ascending aorta phenotype was determined by maximal aortic diameters at the level of the mid-ascending tubular aorta and exceeding 22 mm/m2 or 40 mm in maximal diameter (Figure 2C). Distal ascending/aortic arch phenotype was diagnosed when maximal dimensions were measured at the level of the distal ascending aorta and/or proximal aortic arch and were ≥22 mm/m2 or 40 mm (Figure 2D). Indexed cross-sectional aortic diameter >22 mm/m2 was observed in 34 patients (18%) with a body surface area <1.8 m2 and absolute aortic diameter <40 mm.
Functional/rheological aortic root parameters
The following functional/rheological variables were assessed on the basis of CMR: 1) angulation between left ventricular (LV) outflow axis and aortic root (i.e., LV/aorta angle); 2) aortic valve orifice; 3) location of the aortic segment where the systolic transvalvular flow jet has an impact on the aortic wall; 4) distance (mm) between aortic valve plane and the location of the aortic wall flow jet impact; 5) angle between systolic peak velocity flow jet and location of aortic wall flow jet impact (i.e., jet/aorta angle).
Our CMR protocol and corresponding sequences used for specific measurements were previously described in detail (22). Briefly, the LV/aorta angle was determined at peak systole in the LV inflow-outflow view. The LV outflow axis was modeled as a vector between the LV apex and the midpoint of the LV outflow tract (i.e., 15 mm below the aortic valve plane). Residual aortic valve orifice was defined in the cross-sectional plane positioned at the origin of the systolic transvalvular flow jet and parallel to the aortic annular plane at peak systole. The jet/aorta angle (i.e., the angle at which the flow jet hits the aortic wall) was determined in the flow velocity-encoded window and measured as described in Figure 3.
All morphological/functional CMR parameters were analyzed by 2 study radiologists (B.F. and G.D.) blinded to the intraoperative findings. We have previously demonstrated good intraobserver and interobserver reliability of the LV/aorta angle and jet/aorta angle measurements (22).
Both study groups were comparable in terms of their demographics and intraoperative variables (Table 1). Of note, there was no significant difference in patient age between the study groups. All 190 patients underwent elective AVR surgery with or without concomitant proximal aortic replacement using standard cardiopulmonary bypass. In the BAV group, intraoperative analysis revealed fusion of the right-left coronary cusps (Sievers BAV type 1, L/R) in 99 patients (72%) and right-noncoronary cusps (Sievers BAV type 1, R/N) in the remaining 38 patients (28%) (16). There were no true bicuspid (i.e., Sievers BAV type 0 or left-noncoronary fusion [Sievers BAV type 1, L/N]) patients in our cohort. A total of 27 patients (20%) in the BAV group underwent simultaneous supracoronary ascending aortic replacement, whereas no ascending aortic surgery was performed in the TAV group (Table 1).
Two aortic specimens were collected intraoperatively. The first aortic specimen (the so-called jet sample) was obtained from the area of contact between the systolic transvalvular flow jet and the aortic wall, as determined by pre-operative CMR analysis (i.e., the segment of aortic circumference in direct contact with the flow jet). Intraoperatively, the corresponding aortic area usually demonstrated typical signs of a “jet lesion” (i.e., marked aortic wall thinning/fibrosis). The second sample (i.e., control sample) was collected from the opposite aortic wall. Aortic samples were obtained from the aortotomy incision, which was tailored individually to correspond with the pre-operative CMR data, in 170 patients who underwent isolated AVR. Otherwise, aortic specimens were obtained from excised aneurysmal tissue in the 20 patients (11%) who underwent simultaneous ascending aortic replacement. The details of intraoperative tissue collection were described previously (12).
Histological examination of the aortic tissue and assessment of aortic wall lesions by means of a histological grading scale (0 to 21) were performed as described previously (12). Two study pathologists (B.T. and I.P.) who were blinded to the group affiliation (i.e., BAV group vs. TAV group) and the collection site of aortic specimens (i.e., jet sample vs. control sample) evaluated all specimens.
Standard definitions were used for patient variables and outcomes. Categorical variables are expressed as percentages, and continuous variables (i.e., if normally distributed) are expressed as mean ± SD with range. All continuous variables were tested for normal distribution using the Shapiro-Wilk test. All statistical analyses were performed with SPSS software (version 19.0, IBM Corp., New York, New York). Two-tailed Student t tests for continuous variables and chi-square tests for categorical variables were used for univariate comparisons. Correlation analyses were performed using Pearson correlation. The Fisher r-to-z transformation was used to calculate a z value to assess the significance of the difference between correlation coefficients. Multivariate logistic regression was used to identify independent predictors of indexed aortic diameter >22 mm/m2. All variables with p < 0.1 in the univariate analysis were included in the logistic regression model. All p values ≤0.05 were considered statistically significant.
There was 1 in-hospital death (0.5%) in the BAV group due to multiorgan failure. Four patients (2.1%) experienced a perioperative stroke. All remaining patients had an uneventful post-operative course.
Longitudinal and cross-sectional aortic diameters
Longitudinal and cross-sectional aortic diameters in the BAV versus TAV group are summarized in Table 2. There were significant differences in proximal aortic diameters beginning from the level of aortic annulus to the origin of brachiocephalic trunk between study cohorts, with significantly larger aortic diameters in the BAV group. This difference persisted after indexing cross-sectional aortic dimensions for body surface area (21.1 ± 3.9 mm/m2 vs. 18.8 ± 2.9 mm/m2, p = 0.003). Furthermore, the percentage of patients having indexed cross-sectional aortic diameter ≥22 mm/m2 was higher in the BAV group than in the TAV group (35% vs. 11%, p = 0.008). Moreover, the area of the proximal aorta (Figure 1B) was significantly larger in BAV than in TAV patients (37.1 ± 9.7 cm2 vs. 30.6 ± 4.6 cm2, p < 0.001).
The mid-ascending aorta phenotype was found more commonly in the BAV subgroup than in the TAV subgroup (45% vs. 21%, p = 0.03) (Table 2). Consequently, a concomitant replacement of the supra-coronary ascending aorta was performed more frequently in the BAV group (20% vs. 0%, p = 0.003). In contrast, the normal aorta phenotype was more common in the TAV subgroup (75% vs. 45%, p = 0.007). Aortic root dilation and distal ascending/aortic arch phenotypes were very uncommon in both of our aortic valve stenosis subgroups (Table 2).
Functional/rheological aortic root parameters
All CMR-analyzed functional/rheological aortic root parameters are summarized in Table 3. We found a significant difference between study subgroups in terms of larger LV/aorta angle in the BAV group versus the TAV group (49.8° ± 10.5° vs. 43.9°± 8.1°, p = 0.01). Moreover, the prevalence of patients with angle LV/aorta >50° was significantly higher in the BAV group (43% vs. 17%, p = 0.02). In addition, we compared the LV/aorta angle in 61 BAV stenosis patients to 40 TAV stenosis patients who all had a normal aorta phenotype (Table 2). Both aortic stenosis subgroups with normal aorta (i.e., BAV vs. TAV) had identical indexed cross-sectional and longitudinal aortic diameters and indexed proximal aortic areas. There was a significant difference in the LV/aorta angle between the BAV and TAV groups (47.6° ± 9.3° vs. 42.5° ± 6.8°, p = 0.04).
Asymmetric residual aortic valve orifice was significantly more frequent in the BAV group (28% vs. 2%, p = 0.003). The aortic segment in direct contact with the systolic transvalvular flow jet was located at the greater curvature in nearly all patients in both groups (100% vs. 98%, p = 0.8). Moreover, the systolic transvalvular flow jet hitting the right-lateral segment of the tubular ascending aorta was the most common scenario in both study groups (58% in the BAV group vs. 68% in the TAV group, p = 0.3). The mean distance between the aortic valve plane and the aortic segment in direct contact with the flow jet was comparable between study groups (52.8 ± 10.6 mm in the BAV group vs. 54.4 ± 7.3 mm in the TAV group, p = 0.4).
Although not statistically significant, there was a tendency toward a larger jet/aorta angle in BAV stenosis patients (29.4° ± 8.3° vs. 26.9° ± 4.8°, p = 0.1). Moreover, we found a tendency toward larger jet/aorta angle in BAV right/left-coronary versus BAV right/noncoronary cusp fusion subgroup (30.6° ± 8.3° vs. 27.5° ± 8.5°, respectively, p = 0.08).
Histological aortic wall lesions
Histological sum scores in the jet sample and control sample in both study subgroups are shown in Table 3. There were no significant differences in the histological sum scores of the jet sample (2.9 ± 1.4 vs. 3.4 ± 2.6, p = 0.4) or the individual subcategories of the histological scores between the BAV and TAV groups. Histological lesions were predominantly observed in the subcategories of medionecrosis, cystic medial necrosis, and elastic fragmentation in both study subgroups. Atherosclerotic changes were very infrequent and not significantly different between BAV and TAV patients (0.4 ± 0.3 vs. 0.5 ± 0.3, p = 0.6).
We found similar patterns of histological lesions between jet and control samples in both study groups (Table 3). Histological sum scores were significantly higher in the jet sample than in the control sample and none of the study patients (i.e., in both groups) had higher histological sum score values in the control sample as compared to the jet sample. Moreover, the difference between the histological sum score in the jet sample and the sum score in the control sample was comparable between the BAV group and the TAV group (1.1 ± 0.9 vs. 0.9 ± 0.7, p = 0.6).
There was a significant and comparable linear correlation between histological sum score in the jet sample and the indexed cross-sectional aortic diameter in BAV versus TAV group (r = 0.65, p < 0.01 BAV group vs. r = 0.7, p < 0.01 TAV group, z = –0.56, p = 0.6) (Figure 4A). Moreover, we found a similarity in direction but significantly weaker correlation (i.e., as compared to indexed cross-sectional aortic diameter) between the indexed proximal aortic length (r = 0.45, p < 0.01 and z = 3.1, p = 0.002 BAV group vs. r = 0.55, p < 0.01 and z = 1.8, p = 0.06 TAV group)/indexed proximal aortic area (r = 0.4, p = 0.02 and z = 3.7, p = 0.003 BAV group vs. r = 0.45, p = 0.01 and z = 2.5, p = 0.01 TAV group) and the histological sum score in the jet sample in both subgroups (Figures 4B and 4C).
Expression of aortopathy and functional/rheological parameters
We analyzed the correlation between expression/severity of aortopathy (i.e., proximal aortic shape, cross-sectional and longitudinal aortic diameters, and histological sum score) and the CMR-defined functional/rheological parameters and compared them between the study groups. Results of correlation analysis between parameters of aortopathy and the rheological variables in both study groups are shown in the Central Illustration.
We found the same pattern of linear correlation between indexed cross-sectional aortic diameter and the angle between LV outflow axis and aortic root (LV/aorta angle) in both groups (r = 0.60, p < 0.001 BAV group vs. r = 0.45, p = 0.03 TAV group, z = 1.26, p = 0.2) (Central Illustration). There was a comparable and weak correlation between the indexed proximal aortic length and the LV/aorta angle in the study subgroups (r = 0.35, p = 0.01 BAV group vs. r = 0.30, p = 0.04 TAV group, z = 0.34, p = 0.7) (Central Illustration). Similar findings were obtained in the correlation analysis of indexed proximal aortic area and the LV/aorta angle in the BAV group, whereas no significant correlation was found in the TAV group (Central Illustration). Moreover, there was a nearly identical correlation pattern between the histological sum score in the jet sample and the LV/aorta angle in the BAV group versus the TAV group (r = 0.63, p < 0.01 vs. r = 0.55, p < 0.01, z = 0.74, p = 0.5).
Furthermore, we analyzed the correlation pattern between indexed cross-sectional aortic diameter/proximal aortic length/proximal aortic area and the jet/aorta angle in both study subgroups (Figures 5A to 5C). Although significantly stronger in BAV subgroup, linear correlation pattern was particularly robust between indexed cross-sectional aortic diameter and the jet/aorta angle (r = 0.7, p < 0.01 in BAV group vs. r = 0.45, p = 0.01 in TAV group, z = 2.3, p = 0.02).
Logistic regression analysis was performed to identify predictors of indexed cross-sectional aortic diameter ≥22 mm/m2 (Table 4). Only functional/rheological aortic root parameters (i.e., the LV/aorta angle and the jet/aorta angle) were found to be significantly associated with the indexed cross-sectional aortic diameter ≥22 mm/m2 in our aortic valve stenosis population. Of note, aortic valve morphology (i.e., BAV vs. TAV) had no impact on the occurrence of indexed aortic diameter ≥22 mm/m2 after functional/rheological aortic root parameters were included in the multivariate regression model.
The treatment of mild or moderately dilated proximal aorta in patients with BAV stenosis remains controversial (23).
On the basis of our previous retrospective analysis (15), we hypothesized that similar rheological disturbances might be involved in the genesis of aortic valve stenosis–associated aortopathy in both BAV and TAV patients. Two further studies analyzed the natural history of ascending aortic aneurysms in the setting of unreplaced BAV versus TAV patients and reported similar findings (24,25). These data support our previous hypothesis that the proximal aorta in BAV stenosis behaves similar to the proximal aorta of comparable dimensions in patients with TAV stenosis.
In our current study, we aimed to prospectively assess the associations between aortic valve morphology, alterations in the transvalvular flow and severity/expression of aortopathy by means of pre-operative CMR analysis, CMR-guided sampling of aortic tissue during AVR surgery, and quantitative histological examination of this aortic tissue. The main finding of our study is that correlation patterns between rheological/functional aortic root parameters and expression/severity of aortopathy were comparable in patients with bicuspid versus tricuspid aortic valve stenosis. Although CMR-based aortic measurements revealed consistently larger longitudinal and cross-sectional proximal aortic diameters in BAV patients (Table 2), the impact of aortic valve morphology on the expression/severity of aortopathy was abolished after including rheological/functional aortic root parameters in the multivariate regression model (Table 4).
Our findings might be interpreted as demonstrating that specific transvalvular flow patterns, which are influenced by functional aortic root parameters and not the aortic valve morphology itself (i.e., BAV vs. TAV), are significantly associated with expression of aortopathy in patients with aortic stenosis. In support of this statement, we found that the mid-ascending aorta phenotype was the most common form of aortopathy in both study subgroups (Table 2). Moreover, the values of histological sum score and the asymmetric pattern of histological aortic wall lesions (i.e., histological score in the jet sample vs. control sample) were comparable in patients undergoing surgery for BAV versus TAV stenosis (Table 3). Nonetheless, the larger diameters observed at all levels of the proximal aorta in BAV patients (Table 2) suggest that a genetic component in BAV aortopathy cannot be completely excluded.
Another important finding in our study is that the rheological parameters of systolic transvalvular flow (i.e., angulation between the LV outflow axis and aortic root) are different in the BAV group than in the TAV group (Table 3). Such a finding correlates with the larger longitudinal and cross-sectional aortic diameters and higher prevalence of indexed cross-sectional aortic diameter ≥22 mm/m2, as well as with the mid-ascending aorta phenotype in the BAV study cohort. The same pattern of linear correlation was demonstrated between the LV/aorta angle and the indexed cross-sectional aortic diameter/histological sum score in the jet sample in the BAV group versus the TAV group (Central Illustration). Moreover, the LV/aorta angle was found to be significantly associated with indexed aortic diameter ≥22 mm/m2 in our logistic regression analysis.
A possible explanation for the difference in the LV/aorta angle between BAV and TAV stenosis patients is still lacking. At present, we have no longitudinal comparative CMR data in BAV versus TAV patients and therefore cannot exclude the possibility that this angulation may change over time as proximal aortopathy and/or LV remodeling process progress. Indeed, BAV stenosis is a congenital disorder and therefore the length of time that the aorta is exposed to abnormal post-stenotic blood flow is probably longer than in patients with acquired TAV stenosis. Our finding that both aortic stenosis subgroups with normal aorta (i.e., BAV vs. TAV) still demonstrated a significant difference in the LV/aorta angle further obviates the need for longitudinal imaging data to explore the mechanism that causes the progression of aortopathy.
We also observed a significant association between the jet/aorta angle and proximal aortic diameters (Table 4, Figure 5). The association between flow jet angulations and wall shear stress parameters and aneurysmal disease progression was demonstrated previously in abdominal and cerebral arteries aneurysms (26,27). Moreover, the vascular remodeling processes arising from hemodynamic shear stress–induced endothelial mechanotransduction were shown to include aneurysm formation response (28).
Although longitudinal expansion of the ascending aorta has been observed with advancing age (20), we found the strongest correlation between the histological sum score in the jet sample and the indexed cross-sectional aortic diameter in both study cohorts, as opposed to proximal aortic length and proximal aortic area (Figure 4). Moreover, the rheological/functional aortic root parameters correlated most reliably with the indexed cross-sectional aortic diameter as compared with proximal aortic length and proximal aortic area (Figure 5). Therefore, indexed cross-sectional aortic diameter seems to be the most reliable marker/indicator of aortic valve stenosis–associated aortopathy severity in our study.
Study limitations include the limited sample size of the TAV group. However, our aim was to minimize expected differences in patient risk profiles (i.e., age- and comorbidity-related) between study groups, and we therefore limited age eligibility to <70 years. Limiting the study to nonelderly patients resulted in the reduced TAV sample size. Moreover, as a consequence of this age limitation, our included TAV control group may not be completely representative of the whole TAV stenosis population.
Finally, we did not perform longitudinal CMR studies on the development of BAV versus TAV stenosis–associated aortopathy. It is possible that rheological/functional aortic root parameters may change over time as proximal aortic disease and/or LV remodeling progresses. Therefore, our study only demonstrates associations between functional/rheological parameters and aortopathy and does not provide definitive proof of causality. It remains to be determined whether these parameters are genetically triggered or whether they simply represent a secondary phenomenon in the course of progression of the aortic valve stenosis-associated aortopathy.
Our study demonstrates comparable correlation patterns between functional aortic root parameters and severity/expression of aortopathy in patients with bicuspid versus tricuspid aortic valve stenosis. The present data support further the hypothesis that aortopathy in patients with BAV and TAV stenosis represents a similar and predominantly hemodynamically triggered phenomenon.
COMPETENCY IN MEDICAL KNOWLEDGE: The aortopathy in patients with bicuspid and tricuspid aortic valve stenosis correlates comparably with rheological parameters of the aortic root including the angles relating the aorta, LV, and flow jet.
TRANSLATIONAL OUTLOOK: More detailed examinations of extracellular matrix proteins involved in vascular remodeling and markers of muscle cell maturation may enhance understanding of the mechanism by which aortopathy influences the clinical course of patients with stenotic aortic valves.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- aortic valve replacement
- bicuspid aortic valve
- cardiac magnetic resonance
- left ventricle
- tricuspid aortic valve
- Received January 26, 2016.
- Revision received February 8, 2016.
- Accepted February 8, 2016.
- 2016 American College of Cardiology Foundation
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