Remodelling of the aortic root in severe tricuspid aortic stenosis: implications for transcatheter aortic valve implantation

Classification of severe aortic stenosis and outcomes after aortic valve replacement

Aortic valve calcium scoring by cardiac computed tomographic (CT) has been recommended as an alternative to classify the AS (aortic stenosis) severity, but it is unclear that whether CT findings would have additional value to discriminate significant AS subtypes including high gradient severe AS, classic low-flow, low gradient (LF-LG) AS, paradoxical LF-LG AS, and moderate AS. In this study, we examined the preoperative clinical and cardiac CT findings of different subtypes of AS in patients with surgical aortic valve replacement (AVR) and evaluated the subtype classification as a factor affecting post-surgical outcomes. This study included 511 (66.9 ± 8.8 years, 55% men) consecutive patients with severe AS who underwent surgical AVR. Aortic valve area (AVA) was obtained by echocardiography (AVAecho) and by CT (AVACT) using each modalities measurement of the left ventricular outflow tract. Patients with AS were classified as (1) high-gradient severe (n = 438), (2) classic LF-LG (n = 18), and (3) paradoxical LF-LG (n = 55) based on echocardiography. In all patients, 455 (89.0%) patients were categorized as severe AS according to the AVACT. However, 56 patients were re-classified as moderate AS (43 [9.8%] high-gradient severe AS, 5 [27.8%] classic LF-LG AS, and 8 [14.5%] paradoxical LF-LG AS) by AVACT. The classic LF-LG AS group presented larger AVACT and aortic annulus than those in high-gradient severe AS group and one third of them had AVACT ≥ 1.2 cm2. After multivariable adjustment, old age (hazard ratio [HR], 1.04, P = 0.049), high B-type natriuretic peptide (BNP) (HR, 1.005; P < 0.001), preoperative atrial fibrillation (HR, 2.75; P = 0.003), classic LF-LG AS (HR, 5.53, P = 0.004), and small aortic annulus on CT (HR, 0.57; P = 0.002) were independently associated with major adverse cardiac and cerebrovascular events (MACCE) after surgical AVR.

Sinus of Valsalva Dimension and Clinical Outcomes in Patients Undergoing Transcatheter Aortic Valve Implantation

BACKGROUND

Ascending aortic root anatomy is routinely evaluated on pre-procedural multi-detector computed tomography (MDCT). However, its clinical significance has not been adequately studied. We aimed to investigate the impact of the sinus of Valsalva (SOV) dimension on clinical outcomes in patients undergoing transcatheter aortic valve implantation (TAVI).

METHODS

In a prospective TAVI registry, we retrospectively assessed SOV dimensions by pre-procedural MDCT. Patients were stratified according to tertiles of SOV diameter indexed to body surface area (SOVi). The primary endpoint was all-cause mortality at 1 year.

RESULTS

Among 2066 consecutive patients undergoing TAVI between August 2007 and June 2018, 1554 patients were eligible for the present analysis. Patients in the large SOVi group were older (83 ± 6 vs 82 ± 6 vs 81 ± 6; P < .001) and had a higher Society of Thoracic Surgeons Predicted Risk of Mortality (6.3 ± 3.8 vs 5.1 ± 3.1 vs 4.9 ± 3.5; P < .001) than those in the other groups. Patients in the large SOVi group had a higher incidence of moderate or severe paravalvular regurgitation (11.9% vs 4.5% vs 3.5%; P < .001). At 1 year, a large SOVi was independently associated with an increased risk of mortality (HR: 1.62; 95% CI: 1.19-2.21; P = .002) and major or life-threatening bleeding (HR: 1.30; 95% CI: 1.02-1.65; P = .035).

CONCLUSIONS

Dilatation of the aortic root at the SOV was associated with adverse outcomes after TAVI. The assessment of the aortic root should be integrated into the risk stratification system in patients undergoing TAVI.

Comparison of the geometry of the left ventricle outflow tract, the aortic root and the ascending aorta in patients with severe tricuspid aortic stenosis versus healthy controls

The purpose of this study was to assess by multislice computed tomography (MSCT) imaging geometry of the ascending aorta, the aortic root, the aortic annulus and the left ventricle outflow tract (LVOT) in aortic stenosis (AS) patients, to compare aortic root morphology in patients with AS with healthy controls and to evaluate sex differences. Fifty patients with severe AS and 50 age- and gender-matched controls who underwent MSCT were included in the study. The dimensions of the LVOT, the aortic annulus, the aortic root, the ascending aorta, and the volume of the aortic root were retrospectively assessed and a comparison was made between patients with severe tricuspid AS and controls. Patients with tricuspid AS in comparison with controls had smaller dimensions of the sinus of Valsalva resulting in reduction of the aortic root volume, whereas the dimensions of the other structures were comparable. MSCT revealed larger annular, LVOT and the sinus of Valsalva dimensions and the aortic root volume in men than women. Men with AS differed from healthy men only in regard to the dimensions of the sinus of Valsalva, while women showed significant differences also in the LVOT, and the aortic annulus. MSCT showed accurately aortic root remodeling in tricuspid AS patients and indentified sex-dependent differences. Women with tricuspid AS differ from healthy women more than men did. A high degree of the variability in the aortic root dimensions requires further careful research.

Geometry of the left ventricular outflow tract assessed by 3D TEE in patients with aortic stenosis: impact of upper septal hypertrophy on measurements of Doppler-derived left ventricular stroke volume

BACKGROUND

It is unclear how upper septal hypertrophy (USH) affects Doppler-derived left ventricular stroke volume (SV) in patients with AS. The aims of this study were to: (1) validate the accuracy of 3D transesophageal echocardiography (TEE) measurements of the left ventricular outflow tract (LVOT), (2) evaluate the differences in LVOT geometry between AS patients with and without USH, and (3) assess the impact of USH on measurement of SV.

METHODS

In protocol 1, both 3D TEE and multi-detector computed tomography were performed in 20 patients with AS [aortic valve area (AVA) ≤ 1.5 cm²]. Multiplanar reconstruction was used to measure the LVOT short and long diameters in four parts from the tip of the septum to the annulus. In protocol 2, the same 3D TEE measurements were performed in AS patients (AVA ≤ 1.5 cm², n = 129) and controls (n = 30). We also performed 2D and 3D transthoracic echocardiography in all patients.

RESULTS

In protocol 1, excellent correlations of LVOT parameters were found between the two modalities. In protocol 2, the USH group had smaller LVOT short and long diameters than the non-USH group. Although no differences in mean pressure gradient, or SV calculated with the 3D method existed between the two groups, the USH group had greater SV calculated with the Doppler method (73 ± 15 vs. 66 ± 15 ml) and aortic valve area (0.89 ± 0.26 vs. 0.73 ± 0.24 cm²) than the non-USH group.

CONCLUSIONS

3D TEE can provide a precise assessment of the LVOT in AS. USH affects the LVOT geometry in patients with AS, which might lead to inaccurate assessments of disease severity.

Korean guidelines for the appropriate use of cardiac CT

The development of cardiac CT has provided a non-invasive alternative to echocardiography, exercise electrocardiogram, and invasive angiography and cardiac CT continues to develop at an exponential speed even now. The appropriate use of cardiac CT may lead to improvements in the medical performances of physicians and can reduce medical costs which eventually contribute to better public health. However, until now, there has been no guideline regarding the appropriate use of cardiac CT in Korea. We intend to provide guidelines for the appropriate use of cardiac CT in heart diseases based on scientific data. The purpose of this guideline is to assist clinicians and other health professionals in the use of cardiac CT for diagnosis and treatment of heart diseases, especially in patients at high risk or suspected of heart disease.

Computer-aided design of the human aortic root

The development of computer-based 3D models of the aortic root is one of the most important problems in constructing the prostheses for transcatheter aortic valve implantation. In the current study, we analyzed data from 117 patients with and without aortic valve disease and computed tomography data from 20 patients without aortic valvular diseases in order to estimate the average values of the diameter of the aortic annulus and other aortic root parameters. Based on these data, we developed a 3D model of human aortic root with unique geometry. Furthermore, in this study we show that by applying different material properties to the aortic annulus zone in our model, we can significantly improve the quality of the results of finite element analysis. To summarize, here we present four 3D models of human aortic root with unique geometry based on computational analysis of ECHO and CT data. We suggest that our models can be utilized for the development of better prostheses for transcatheter aortic valve implantation.

Quantitative Analysis of Aortic Valve Stenosis and Aortic Root Dimensions by Three-Dimensional Echocardiography in Patients Scheduled for Transcutaneous Aortic Valve Implantation

Accurate assessment of the aortic valve area (AVA) and evaluation of the aortic root are important for clinical decision-making in patients being considered for transcatheter aortic valve implantation (TAVI). Real-time three-dimensional transesophageal echocardiography (RT3D-TEE) provides accurate and reliable quantitative assessment of aortic valve stenosis and the aortic root. We performed two-dimensional transthoracic echocardiography (2D-TTE), real-time 2D transesophageal echocardiography (RT2D-TEE) and RT3D-TEE in 71 consecutive patients referred for TAVI. RT3D-TEE multiplanar reconstruction was used to measure aortic root parameters, including left ventricular outflow tract (LVOT) diameter and area, aortic annulus diameter, aortic annulus area, and AVA. RT3D-TEE methods for planimetry and the LVOT-derived continuity equation for the estimation of AVA showed a good correlation. As iatrogenic coronary ostium occlusion is a potentially life-threatening complication, we evaluated the distances from the aortic annulus to the coronary ostia using RT3D-TEE. Based on our findings, we conclude that the geometry of the aortic root and aortic valve can be reliably and feasibly evaluated using RT3D-TEE, which is important for protecting against potential complications of TAVI, such as underestimation of the size of the aortic annulus that can result in aortic regurgitation and dislocation of the valve, or overestimation can lead to annulus rupture.

An insight into transcatheter aortic valve implantation-a perspective from multidetector-computed tomography

Transcatheter aortic valve implantation (TAVI) has now become an acceptable alternative to surgical aortic valve replacement for patients with severe aortic stenosis at high risk. The early enthusiasm for this technology has not diminished but rather has developed at an unprecedented rate over the last decade. Alongside the developments in implantation technique, transcatheter design, and postprocedural care, cardiac imaging modalities have also had to concurrently evolve to meet the perpetual demand for lower peri- and postprocedural complication rates. Although transthoracic and transesophageal echocardiography remain vital in patient's selection and periprocedural guidance, there is now emerging evidence that indicates that multidetector-computed tomography (MDCT) may also have an equally important role to play. The aim of the current review is to examine the modern role of MDCT in assessing patients with aortic stenosis being considered for TAVI.

Aortic root geometry in patients with aortic stenosis assessed by real-time three-dimensional transesophageal echocardiography

BACKGROUND

The authors hypothesized that aortic root geometry is different between bicuspid and tricuspid aortic stenosis (AS) that can be assessed using real-time three-dimensional (3D) transesophageal echocardiography. The aims of this study were (1) to validate the accuracy of 3D transesophageal echocardiographic measurements of the aortic root against multidetector computed tomography as a reference, (2) to determine the difference of aortic root geometry between patients with tricuspid and bicuspid AS, and (3) to assess its impact on pressure recovery.

METHODS

In protocol 1, 3D transesophageal echocardiography and contrast-enhanced multidetector computed tomography were performed in 40 patients. Multiplanar reconstruction was used to measure the aortic annulus, the sinus of Valsalva, and the sinotubular junction area, as well as the distance and volume from the aortic annulus to the sinotubular junction. In protocol 2, the same 3D transesophageal echocardiographic measurements were performed in patients with tricuspid AS (n = 57) and bicuspid AS (n = 26) and in patients without AS (n = 32). The energy loss coefficient was also measured in patients with AS.

RESULTS

In protocol 1, excellent correlations of aortic root geometric parameters were noted between the two modalities. In protocol 2, compared with patients without AS, those with tricuspid AS had smaller both sinotubular junction areas and longitudinal distances, resulting in a 23% reduction of aortic root volume. In contrast, patients with bicuspid AS had larger transverse areas and longitudinal distances, resulting in a 30% increase in aortic root volume. The energy loss coefficient revealed more frequent reclassification from severe AS to moderate AS in patients with tricuspid AS (17%) compared with those with bicuspid AS (10%).

CONCLUSIONS

Three-dimensional transesophageal echocardiography successfully revealed different aortic root morphologies between tricuspid and bicuspid AS, which have different impacts on pressure recovery.

The role of computed tomography in pre-procedural planning of cardiovascular surgery and intervention

Advances in our knowledge of cardiovascular disorders coupled with technological innovations have enabled the increased use of minimally invasive cardiovascular surgeries and transcatheter interventions, with resultant reduced morbidity and hospital stay. Three-dimensional imaging, particularly computed tomography (CT) is increasingly used for patient selection, providing a roadmap of the anatomy and identifying factors that may complicate these procedures. Advantages of CT are the rapid turnaround time, good spatial and temporal resolutions, wide field of view and three-dimensional multi-planar reconstruction capabilities. This pictorial review describes the role of CT in the pre-operative evaluation of patients undergoing cardiovascular surgeries and intervention. Main Messages • CT scan is valuable in pre-operative evaluation for cardiac surgeries • Cardiovascular structures, including bypass grafts should be located >10 mm from the sternum in patients for reoperative cardiothoracic surgeries • Knowledge of variations in pulmonary venous anatomy are essential for planning radiofrequency ablation.

Non-invasive and invasive evaluation of aortic valve area in 100 patients with severe aortic valve stenosis: comparison of cardiac computed tomography with ECHO (transesophageal/transthoracic) and catheter examination

BACKGROUND

Current guidelines place emphasis on the determination of aortic valve area (AVA) for defining an appropriate treatment strategy. Invasive and non-invasive modalities are used to perform planimetric [transesophageal echocardiography (TEE) and cardiac multidetector computed tomography (MDCT)] and calculated [catheter examination (CE), transthoracic echocardiography (TTE)] AVA measurements.

PURPOSE AND METHODS

We investigated 100 patients admitted to evaluate the AVA using cardiac MDCT (CT), TEE/TTE as well as invasive CE.

RESULTS

In all 100 patients we calculated a mean AVA of 0.79±0.29cm(2) (female 50/100, 0.70±0.19cm(2), male 0.9±0.21cm(2)) determined by all investigated examinations (mean±SEM). AVA measurements determined by CT were significantly greater (0.86±0.25cm(2)) than those determined by CE: 0.75±0.18cm(2), p=0.01. Echocardiographically determined AVA was comparable to CE (statistically not significant). Similar results were seen in all patients regardless of gender, presence of atrial fibrillation, and heart rate. We calculated a mean AVA for each patient and evaluated the variance of the AVA determined through investigated specific examinations as the bias. Overall, we found for CT 0.13±0.1cm(2), CE 0.13±0.11cm(2), TEE 0.16±0.09cm(2), and for TTE 0.16±0.08cm(2) a specific statistical non-significant variance. On subgroups: sinus rhythm, atrial fibrillation, females, males or combination, we found no further significant relevance for the specific variance.

CONCLUSION

Our data suggest the feasibility of cardiac MDCT to evaluate the correct AVA regardless of rhythm, heart rate, and sex. The planimetric concept to determine the AVA with CT displaces the "gold-standard" CE with respect to elucidating the potencies for complications, i.e. cerebral stroke. Regardless of CT's accessing of AVA measurement the TTE examination should remain the primary method of screening for aortic valve pathologies.

Is real time 3D transesophageal echocardiography a feasible approach to detect coronary ostium during transapical aortic valve implantation?

OBJECTIVE

Transapical aortic valve implantation (TAVI) may lead to obstruction of coronary arteries during deployment. To prevent this, it is essential to determine the distance of the coronary ostium to the aortic annulus prior to valve placement. Multidetector computed tomography (MDCT) commonly is used to determine these measurements, but even marginal exposure to contrast agents can result in acute kidney injury in this high-risk group of multi-morbid patients. The aim of the study was to determine the feasibility of real-time 3D transesophageal echocardiography (RT 3D TEE) as the first-choice technique for noninvasive evaluation of the coronary ostium during TAVI.

DESIGN

Retrospective study.

SETTING

University hospital.

INTERVENTIONS

Fifty patients underwent MDCT the evening before surgery. RT 3D TEE was performed intraoperatively before valve deployment. The dataset from both of these examinations was digitally stored and evaluated. MDCT was performed in nonanesthetized patients; however, in the RT 3D TEE group, general anesthesia was established.

MEASUREMENTS AND MAIN RESULTS

The distances from the right coronary artery and the left coronary artery ostium were measured retrospectively. Bland-Altman Plots and linear regression analysis showed excellent correlation between the 2 methodologies; intraobserver and interobserver variance were calculated using analysis of variance. Krippendorff's α indicated excellent agreement between the 2 observers (0.96 and 0.98) as well as between RT 3D TEE and MDCT (0.97 and 0.98).

CONCLUSIONS

The observations showed that RT 3D TEE reliably can measure the coronary ostium distance from the aortic annulus. It is feasible and an alternative method for evaluating these measurements and thereby preventing contrast exposure during MDCT, which may jeopardize the safety of patients with pre-existing renal disease.

Patient-specific modeling of biomechanical interaction in transcatheter aortic valve deployment

The objective of this study was to develop a patient-specific computational model to quantify the biomechanical interaction between the transcatheter aortic valve (TAV) stent and the stenotic aortic valve during TAV intervention. Finite element models of a patient-specific stenotic aortic valve were reconstructed from multi-slice computed tomography (MSCT) scans, and TAV stent deployment into the aortic root was simulated. Three initial aortic root geometries of this patient were analyzed: (a) aortic root geometry directly reconstructed from MSCT scans, (b) aortic root geometry at the rapid right ventricle pacing phase, and (c) aortic root geometry with surrounding myocardial tissue. The simulation results demonstrated that stress, strain, and contact forces of the aortic root model directly reconstructed from MSCT scans were significantly lower than those of the model at the rapid ventricular pacing phase. Moreover, the presence of surrounding myocardium slightly increased the mechanical responses. Peak stresses and strains were observed around the calcified regions in the leaflets, suggesting the calcified leaflets helped secure the stent in position. In addition, these elevated stresses induced during TAV stent deployment indicated a possibility of tissue tearing and breakdown of calcium deposits, which might lead to an increased risk of stroke. The potential of paravalvular leak and occlusion of coronary ostia can be evaluated from simulated post-deployment aortic root geometries. The developed computational models could be a valuable tool for pre-operative planning of TAV intervention and facilitate next generation TAV device design.

A systematic approach for analysis, interpretation, and reporting of coronary CTA studies

Over the past years, the number of coronary computed tomography angiography (CTA) studies performed worldwide has been steadily increasing. Performing a coronary CTA study with appropriate protocols tailored to the individual patient and clinical question is mandatory to obtain an image quality that is diagnostic for the study purpose. This process can be considered the primary mainstay of each coronary CTA study. The secondary mainstay is represented by the correct analysis and interpretation of the acquired data, as well as reporting of the pertinent imaging findings to the referring physician. The latter process requires knowledge of the advantages and disadvantages of various post-processing methods. In addition, a standardized approach can be helpful to avoid false-positive and false-negative findings regarding the presence or absence of coronary artery disease. By implementing various radiation dose reduction techniques, care needs to be taken to keep the radiation dose of coronary CTA as low as reasonably achievable while maintaining the diagnostic capacity of the examination. This review describes a practical approach to the analysis and interpretation of coronary CTA data, including the standardized reporting of the relevant imaging findings to the referring physicians.

Influence of left ventricular geometry and function on aortic annular dimensions as assessed with multi-detector row computed tomography: implications for transcatheter aortic valve implantation

AIMS

Evaluate changes in aortic annular dimensions in relation to severe aortic stenosis (AS) and left ventricular (LV) dysfunction.

METHODS AND RESULTS

Mean aortic annular diameters and geometries were compared between 90 severe AS patients and 111 controls by multi-detector row computed tomography (MDCT). All severe AS patients were also dichotomized into two groups based on the presence of preserved (≥ 50%) or impaired (<50%) LV ejection fraction (EF). The influence of LV geometry and function on changes in aortic annular dimensions was examined. Patients with severe AS had similar aortic annular dimensions and geometries compared with controls even after correcting for baseline differences in age and body surface area (BSA). However, severe AS patients with LV dysfunction (LVEF <50%) had significantly larger mean aortic annular diameter (26.4 ± 1.9 vs. 24.5 ± 2.1 mm, P < 0.001) compared with patients with preserved LVEF. The presence of LV dysfunction, male gender, and larger BSA were independent determinants of a larger aortic annulus on MDCT.

CONCLUSION

In severe AS patients, the presence of LV dysfunction, not the presence of severe AS, was an independent determinant of a larger aortic annular diameter.

Comparison between cardiovascular magnetic resonance and transthoracic Doppler echocardiography for the estimation of effective orifice area in aortic stenosis

BACKGROUND

The effective orifice area (EOA) estimated by transthoracic Doppler echocardiography (TTE) via the continuity equation is commonly used to determine the severity of aortic stenosis (AS). However, there are often discrepancies between TTE-derived EOA and invasive indices of stenosis, thus raising uncertainty about actual definite severity. Cardiovascular magnetic resonance (CMR) has emerged as an alternative method for non-invasive estimation of valve EOA. The objective of this study was to assess the concordance between TTE and CMR for the estimation of valve EOA.

METHODS AND RESULTS

31 patients with mild to severe AS (EOA range: 0.72 to 1.73 cm2) and seven (7) healthy control subjects with normal transvalvular flow rate underwent TTE and velocity-encoded CMR. Valve EOA was calculated by the continuity equation. CMR revealed that the left ventricular outflow tract (LVOT) cross-section is typically oval and not circular. As a consequence, TTE underestimated the LVOT cross-sectional area (ALVOT, 3.84 ± 0.80 cm2) compared to CMR (4.78 ± 1.05 cm2). On the other hand, TTE overestimated the LVOT velocity-time integral (VTILVOT: 21 ± 4 vs. 15 ± 4 cm). Good concordance was observed between TTE and CMR for estimation of aortic jet VTI (61 ± 22 vs. 57 ± 20 cm). Overall, there was a good correlation and concordance between TTE-derived and CMR-derived EOAs (1.53 ± 0.67 vs. 1.59 ± 0.73 cm2, r = 0.92, bias = 0.06 ± 0.29 cm2). The intra- and inter- observer variability of TTE-derived EOA was 5 ± 5% and 9 ± 5%, respectively, compared to 2 ± 1% and 7 ± 5% for CMR-derived EOA.

CONCLUSION

Underestimation of ALVOT by TTE is compensated by overestimation of VTILVOT, thereby resulting in a good concordance between TTE and CMR for estimation of aortic valve EOA. CMR was associated with less intra- and inter- observer measurement variability compared to TTE. CMR provides a non-invasive and reliable alternative to Doppler-echocardiography for the quantification of AS severity.

Assessment of the aortic root using real-time 3D transesophageal echocardiography

BACKGROUND

Precise evaluation of the aortic root geometry prior to transcatheter aortic valve implantation is important for procedural success in patients with aortic stenosis (AS). To determine the potential for 3-dimensional transesophageal echocardiography (3DTEE), the aims of the present study were: (1) to assess the accuracy of 3DTEE measurements of the aortic root using multidetector computed tomography (MDCT) as a reference, and (2) to examine whether aortic root geometry differs between patients with and without AS.

METHODS AND RESULTS

  3DTEE and contrast-enhanced MDCT were performed in 35 patients. Multiplanar reconstruction was used to measure the left ventricular outflow tract (LVOT) and aortic annulus diameter/area, aortic valve area (AVA), and distances between the annulus and coronary artery ostium. The same 3DTEE measurements were performed in patients with (n=71) and without AS (n=80). Aortic annular and LVOT areas measured by 3DTEE were slightly but significantly smaller compared with values obtained with MDCT. Both methods revealed that the aortic annulus and LVOT have an oval shape. Aortic annular and LVOT area, AVA and the distances between the aortic annulus and the coronary ostia correlated well between the 2 modalities. Only minor differences in aortic root geometry were observed between patients with AS and those without.

CONCLUSIONS

The geometry of the aortic annulus can be reliably evaluated using 3DTEE as an alternative to MDCT for the assessment of aortic root.

High-pitch dual-source CT angiography of the aortic valve-aortic root complex without ECG-synchronization

PURPOSE

To compare image quality and radiation dose of high-pitch computed tomography angiography(CTA) of the aortic valve-aortic root complex with and without prospective ECG-gating compared to a retrospectively ECG-gated standard-pitch acquisition.

MATERIALS AND METHODS

120 patients (mean age 68±13 years) were examined using a 128-slice dual-source CT system using prospectively ECG-gated high-pitch (group A; n=40), non-ECG-gated high-pitch (group B; n=40) or retrospectively ECG-gated standard-pitch (C; n=40) acquisition techniques. Image quality of the aortic root, valve and ascending aorta including the coronary ostia was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated.

RESULTS

Interobserver agreement was good(κ=0.64-0.78). Image quality was diagnostic in 38/40 patients (group A), 37/40(B) and 38/40(C) with no significant difference in number of patients with diagnostic image quality among all groups (p=0.56). Significantly more patients showed excellent image quality in group A compared to groups B and C (each, p<0.01). Average image noise was significantly different between all groups (p<0.05). Mean radiation dose estimates in groups A and B (each; 2.4±0.3 mSv) were significantly lower compared to group C (17.5±4.4 mSv; p<0.01).

CONCLUSION

High-pitch dual-source CTA provides diagnostic image quality of the aortic valve-aortic root complex even without ECG-gating at 86% less radiation dose when compared to a standard-pitch ECG-gated acquisition.

Emerging approaches of transcatheter valve repair/insertion

Aortic stenosis (AS) and mitral regurgitation (MR) account for the majority of valvular diseases and their prevalence is increasing according to increased life expectancy. Surgical treatment is the gold standard, although operative risk may be high in some patients due to comorbidities and age. A large part of the patients at high surgical risk who could beneficiate of treatment are not referred to surgery. Therefore, there is a need of alternative and less invasive procedures.

Pre-procedural imaging of aortic root orientation and dimensions: comparison between X-ray angiographic planar imaging and 3-dimensional multidetector row computed tomography

OBJECTIVES

We sought to examine whether contrast-enhanced multidetector row computed tomography (MDCT) allows prediction of X-ray angiographic planes for the root angiogram in the context of transcatheter aortic valve implantation.

BACKGROUND

Understanding of aortic root orientation relative to the body axis is critical for precise positioning of the stent/valve during transcatheter aortic valve implantation.

METHODS

Forty patients with severe aortic stenosis underwent conventional X-ray angiography and contrast-enhanced MDCT of the aortic root. Oblique MDCT images of the aortic root, corresponding to X-ray angiographic left anterior oblique (LA)/right anterior oblique (RAO) projections, were created. The cranial/caudal angulation was compared between angiographic and reformatted MDCT images. In addition, root diameter measurements were compared.

RESULTS

The cranial angulation in the LAO X-ray angiograms (mean LAO: 39+/- 8, n = 38) and matched MDCT images were not significantly different (cranial: 25 +/- 7 vs. 23 +/- 8; p = 0.214). There was a small but significant difference between the caudal angulation in the RAO angiogram (mean RAO: 25 +/- 5, n = 40) and matched CT images (caudal: 21 +/- 9 vs. 29 +/- 10; p = 0.002). The annulus diameter in the LAO projection was not significantly different between X-ray angiography and contrast-enhanced MDCT (2.3 +/- 0.3 vs. 2.4 +/- 0.3; p = 0.052), whereas there was a small but significant difference in the annulus diameter in RAO projections between angiography and MDCT (2.4 +/- 0.3 vs. 2.2 +/- 0.3; p = 0.029).

CONCLUSIONS

Pre-procedural contrast-enhanced MDCT imaging of the aortic root allows prediction of X-ray angiographic planes and contributes to planning of the transcatheter aortic valve implantation.