Arnold C.T. Ng

Comparison of Aortic Root Dimensions and Geometries Before and After Transcatheter Aortic Valve Implantation by 2- and 3-Dimensional Transesophageal Echocardiography and Multislice Computed Tomography

Background—3D transesophageal echocardiography (TEE) may provide more accurate aortic annular and left ventricular outflow tract (LVOT) dimensions and geometries compared with 2D TEE. We assessed agreements between 2D and 3D TEE measurements with multislice computed tomography (MSCT) and changes in annular/LVOT areas and geometries after transcatheter aortic valve implantations (TAVI). Methods and Results—Two-dimensional circular (&pgr;×r2), 3D circular, and 3D planimetered annular and LVOT areas by TEE were compared with “gold standard” MSCT planimetered areas before TAVI. Mean MSCT planimetered annular area was 4.65±0.82 cm2 before TAVI. Annular areas were underestimated by 2D TEE circular (3.89±0.74 cm2, P<0.001), 3D TEE circular (4.06±0.79 cm2, P<0.001), and 3D TEE planimetered annular areas (4.22±0.77 cm2, P<0.001). Mean MSCT planimetered LVOT area was 4.61±1.20 cm2 before TAVI. LVOT areas were underestimated by 2D TEE circular (3.41±0.89 cm2, P<0.001), 3D TEE circular (3.89±0.94 cm2, P<0.001), and 3D TEE planimetered LVOT areas (4.31±1.15 cm2, P<0.001). Three-dimensional TEE planimetered annular and LVOT areas had the best agreement with respective MSCT planimetered areas. After TAVI, MSCT planimetered (4.65±0.82 versus 4.20±0.46 cm2, P<0.001) and 3D TEE planimetered (4.22±0.77 versus 3.62±0.43 cm2, P<0.001) annular areas decreased, whereas MSCT planimetered (4.61±1.20 versus 4.84±1.17 cm2, P=0.002) and 3D TEE planimetered (4.31±1.15 versus 4.55±1.21 cm2, P<0.001) LVOT areas increased. Aortic annulus and LVOT became less elliptical after TAVI. Conclusions—Before TAVI, 2D and 3D TEE aortic annular/LVOT circular geometric assumption underestimated the respective MSCT planimetered areas. After TAVI, 3D TEE and MSCT planimetered annular areas decreased as it assumes the internal dimensions of the prosthetic valve. However, planimetered LVOT areas increased due to a more circular geometry.

Relative Merits of Left Ventricular Dyssynchrony, Left Ventricular Lead Position, and Myocardial Scar to Predict Long-Term Survival of Ischemic Heart Failure Patients Undergoing Cardiac Resynchronization Therapy

Background— The relative merits of left ventricular (LV) dyssynchrony, LV lead position, and myocardial scar to predict long-term outcome after cardiac resynchronization therapy remain unknown and were evaluated in the present study. Methods and Results— In 397 ischemic heart failure patients, 2-dimensional speckle tracking imaging was performed, with comprehensive assessment of LV radial dyssynchrony, identification of the segment with latest mechanical activation, and detection of myocardial scar in the segment where the LV lead was positioned. For LV dyssynchrony, a cutoff value of 130 milliseconds was used. Segments with <16.5% radial strain in the region of the LV pacing lead were considered to have extensive myocardial scar (>50% transmurality, validated in a subgroup with contrast-enhanced magnetic resonance imaging). The LV lead position was derived from chest x-ray. Long-term follow-up included all-cause mortality and hospitalizations for heart failure. Mean baseline LV radial dyssynchrony was 133±98 milliseconds. In 271 patients (68%), the LV lead was placed at the latest activated segment (concordant LV lead position), and the mean value of peak radial strain at the targeted segment was 18.9±12.6%. Larger LV radial dyssynchrony at baseline was an independent predictor of superior long-term survival (hazard ratio, 0.995; P=0.001), whereas a discordant LV lead position (hazard ratio, 2.086; P=0.001) and myocardial scar in the segment targeted by the LV lead (hazard ratio, 2.913; P<0.001) were independent predictors of worse outcome. Addition of these 3 parameters yielded incremental prognostic value over the combination of clinical parameters. Conclusions— Baseline LV radial dyssynchrony, discordant LV lead position, and myocardial scar in the region of the LV pacing lead were independent determinants of long-term prognosis in ischemic heart failure patients treated with cardiac resynchronization therapy. Larger baseline LV dyssynchrony predicted superior long-term survival, whereas discordant LV lead position and myocardial scar predicted worse outcome.

Transcatheter aortic valve implantation: role of multi-detector row computed tomography to evaluate prosthesis positioning and deployment in relation to valve function

AIMS Aortic regurgitation after transcatheter aortic valve implantation (TAVI) is one of the most frequent complications. However, the underlying mechanisms of this complication remain unclear. The present evaluation studied the anatomic and morphological features of the aortic valve annulus that may predict aortic regurgitation after TAVI. METHODS AND RESULTS In 53 patients with severe aortic stenosis undergoing TAVI, multi-detector row computed tomography (MDCT) assessment of the aortic valve apparatus was performed. For aortic valve annulus sizing, two orthogonal diameters were measured (coronal and sagittal). In addition, the extent of valve calcifications was quantified. At 1-month follow-up after procedure, MDCT was repeated to evaluate and correlate the prosthesis deployment to the presence of aortic regurgitation. Successful procedure was achieved in 48 (91%) patients. At baseline, MDCT demonstrated an ellipsoid shape of the aortic valve annulus with significantly larger coronal diameter when compared with sagittal diameter (25.1 +/- 2.4 vs. 22.9 +/- 2.0 mm, P < 0.001). At follow-up, MDCT showed a non-circular deployment of the prosthesis in six (14%) patients. Moderate post-procedural aortic regurgitation was observed in five (11%) patients. These patients showed significantly larger aortic valve annulus (27.3 +/- 1.6 vs. 24.8 +/- 2.4 mm, P = 0.007) and more calcified native valves (4174 +/- 1604 vs. 2444 +/- 1237 HU, P = 0.005) at baseline and less favourable deployment of the prosthesis after TAVI. CONCLUSION Multi-detector row computed tomography enables an accurate sizing of the aortic valve annulus and constitutes a valuable imaging tool to evaluate prosthesis location and deployment after TAVI. In addition, MDCT helps to understand the underlying mechanisms of post-procedural aortic regurgitation.

Findings from left ventricular strain and strain rate imaging in asymptomatic patients with type 2 diabetes mellitus

Regional left ventricular (LV) myocardial functional changes in early diabetic cardiomyopathy have not been well documented. LV multidirectional strain and strain rate analyses by 2-dimensional speckle tracking were used to detect subtle myocardial dysfunction in 47 asymptomatic, male patients (age 57 +/- 6 years) with type 2 diabetes mellitus. The results were compared to those from 53 male controls matched by age, body mass index, and body surface area. No differences were found in the LV end-diastolic volume index (40.7 +/- 8.9 vs 44.1 +/- 7.8 ml/m(2), p = NS), end-systolic volume index (16.0 +/- 4.8 vs 17.8 +/- 4.3 ml/m(2), p = NS), ejection fraction (61.0 +/- 5.5% vs 59.8 +/- 5.3%, p = NS). The transmitral E/A (0.95 +/- 0.21 vs 1.12 +/- 0.32, p = 0.007) and pulmonary S/D (1.45 +/- 0.28 vs 1.25 +/- 0.27, p = 0.001) ratios were more impaired in the patients with diabetes mellitus. Importantly, the diabetic patients had impaired longitudinal, but preserved circumferential and radial systolic and diastolic, function. Diabetes mellitus was an independent predictor for longitudinal strain, systolic strain rate and early diastolic strain rate on multiple linear regression analysis (all p <0.001). In conclusion, the LV longitudinal systolic and diastolic function were impaired, but the circumferential and radial functions were preserved in patients with uncomplicated type 2 diabetes mellitus.

Alterations in multidirectional myocardial functions in patients with aortic stenosis and preserved ejection fraction: a two-dimensional speckle tracking analysis

AIMS To identify changes in multidirectional strain and strain rate (SR) in patients with aortic stenosis (AS). METHODS AND RESULTS A total of 420 patients (age 66.1 ± 14.5 years, 60.7% men) with aortic sclerosis, mild, moderate, and severe AS with preserved left ventricular (LV) ejection fraction [(EF), ≥50%] were included. Multidirectional strain and SR imaging were performed by two-dimensional speckle tracking. Patients were more likely to be older (P < 0.001) and at a worse New York Heart Association functional class (P < 0.001) with increasing AS severity. There was a progressive stepwise impairment in longitudinal, circumferential, and radial strain and SR with increasing AS severity (all P < 0.001). The myocardial dysfunction appeared to start in the subendocardium with mild AS, to mid-wall dysfunction with moderate AS, and eventually transmural dysfunction with severe AS. Aortic valve area, as a measure of AS severity, was an independent determinant of multidirectional strain and SR on multiple linear regressions. CONCLUSIONS Patients with AS have evidence of subclinical myocardial dysfunction early in the disease process despite normal LVEF. The myocardial dysfunction appeared to start in the subendocardium and progressed to transmural dysfunction with increasing AS severity. Symptomatic moderate and severe AS patients had more impaired multidirectional myocardial functions compared with asymptomatic patients.

Myocardial steatosis and biventricular strain and strain rate imaging in patients with type 2 diabetes mellitus.

Background— Magnetic resonance spectroscopy can quantify myocardial triglyceride content in type 2 diabetic patients. Its relation to alterations in left (LV) and right (RV) ventricular myocardial functions is unknown. Methods and Results— A total of 42 men with type 2 diabetes mellitus were recruited. Exclusion criteria included hemoglobin A1c >8.5%, known cardiovascular disease, diabetes-related complications, or blood pressure >150/85 mm Hg. Myocardial ischemia was excluded by a negative dobutamine stress test. LV and RV volumes and ejection fraction were quantified by magnetic resonance imaging. LV global longitudinal and RV free wall longitudinal strain, systolic strain rate, and diastolic strain rate were quantified by echocardiographic speckle tracking analyses. Myocardial triglyceride content was quantified by magnetic resonance spectroscopy and dichotomized on the basis of the median value of 0.76%. The median age was 59 years (25th and 75th percentiles, 54 and 62 years). Median diabetes diagnosis duration was 4 years, and median glycohemoglobin level was 6.2% (25th and 75th percentiles, 5.9% and 6.8%). There were no differences in LV and RV end-diastolic and end-systolic volume indexes and ejection fraction between patients with high (≥0.76%) and those with low (<0.76%) myocardial triglyceride content. However, patients with high myocardial triglyceride content had greater impairment of LV and RV myocardial strain and strain rate. The myocardial triglyceride content was an independent correlate of LV and RV longitudinal strain, systolic strain rate, and diastolic strain rate. Conclusions— High myocardial triglyceride content is associated with more pronounced impairment of LV and RV functions in men with uncomplicated type 2 diabetes mellitus.

Impact of left ventricular systolic function on clinical and echocardiographic outcomes following transcatheter aortic valve implantation for severe aortic stenosis

BACKGROUND This study aimed to evaluate the impact of baseline left ventricular (LV) systolic function on clinical and echocardiographic outcomes following transcatheter aortic valve implantation (TAVI). Survival of patients undergoing TAVI was also compared with that of a population undergoing surgical aortic valve replacement. METHODS One hundred forty-seven consecutive patients (mean age=80±7 years) undergoing TAVI in 2 centers were included. Mean follow-up period was 9.1±5.1 months. RESULTS At baseline, 34% of patients had impaired LV ejection fraction (LVEF) (<50%) and 66% had normal LVEF (≥50%). Procedural success was similar in these 2 groups (94% vs 97%, P=.41). All patients achieved improvement in transvalvular hemodynamics. At follow-up, patients with a baseline LVEF<50% showed marked LV reverse remodeling, with improvement of LVEF (from 37%±8% to 51%±11%). Early and late mortality rates were not different between the 2 groups, despite a higher rate of combined major adverse cardiovascular events (MACEs) in patients with a baseline LVEF<50%. The predictors of cumulative MACEs were baseline LVEF (HR=0.97, 95% CI=0.94-0.99) and preoperative frailty (HR=4.20, 95% CI=2.00-8.84). In addition, long-term survival of patients with impaired or normal LVEF was comparable with that of a matched population who underwent surgical aortic valve replacement. CONCLUSIONS TAVI resulted in significant improvement in LV function and survival benefit in high-risk patients with severe aortic stenosis, regardless of baseline LVEF. Patients with a baseline LVEF<50% were at higher risk of combined MACEs.

Intraoperative 2D and 3D transoesophageal echocardiographic predictors of aortic regurgitation after transcatheter aortic valve implantation

Background Post-procedural aortic regurgitation (AR) has been described in a large number of patients receiving transcatheter aortic valve implantation (TAVI). Objective The aim of this study was to examine the intraoperative 2-dimensional (2D) and 3-dimensional (3D) echocardiographic features of the aortic valve associated with significant post-procedural paravalvular AR. Methods A total of 135 patients (81±7 years) with severe symptomatic aortic stenosis, who underwent TAVI, were imaged with comprehensive 2D and 3D transoesophageal echocardiography before the procedure and peri-procedure. Various baseline and peri-procedural echocardiographic characteristics were tested to predict paravalvular AR post-TAVI: calcifications at the aortic valve commissures and leaflets, ‘aortic annulus eccentricity index’, ‘area cover index’, overlap between aortic prosthesis and anterior mitral leaflet. Post-procedural paravalvular AR≥2 was considered significant. Results Successful TAVI was achieved in all patients. The incidence of paravalvular AR≥2 immediately after the procedure was 21% (28 patients). Commissural calcifications and, particularly, the calcification of the commissure between the right coronary and non-coronary cusps was significantly more frequent in presence of paravalvular AR; the area cover index pre-TAVI was significantly lower among patients with AR (11.1±11.8% vs 20.8±12.5%, p=0.0004). Multivariate analysis revealed that calcification of the commissure between the right coronary and non-coronary cusps (OR=2.66, 95% CI 1.39 to 5.12, p=0.001), and the area cover index pre-TAVI (OR=0.95, 95% CI 0.91 to 0.99, p=0.006) were the only independent predictors of significant paravalvular AR after TAVI. Conclusions Intraoperative 2D and 3D transoesophageal echocardiography identified calcification of the commissure between the right coronary and non-coronary cusps and the area cover index as independent predictors of significant paravalvular AR following TAVI.

Association between diffuse myocardial fibrosis by cardiac magnetic resonance contrast-enhanced T(1) mapping and subclinical myocardial dysfunction in diabetic patients: a pilot study.

Background— Diabetic patients have increased interstitial myocardial fibrosis on histological examination. Magnetic resonance imaging (MRI) T1 mapping is a previously validated imaging technique that can quantify the burden of global and regional interstitial fibrosis. However, the association between MRI T1 mapping and subtle left ventricular (LV) dysfunction in diabetic patients is unknown. Methods and Results— Fifty diabetic patients with normal LV ejection fraction (EF) and no underlying coronary artery disease or regional macroscopic scar on MRI delayed enhancement were prospectively recruited. Diabetic patients were compared with 19 healthy controls who were frequency matched in age, sex and body mass index. There were no significant differences in mean LV end-diastolic volume index, end-systolic volume index and LVEF between diabetic patients and healthy controls. Diabetic patients had significantly shorter global contrast-enhanced myocardial T1 time (425±72 ms vs. 504±34 ms, P<0.001). There was no correlation between global contrast-enhanced myocardial T1 time and LVEF (r=0.14, P=0.32) in the diabetic patients. However, there was good correlation between global contrast-enhanced myocardial T1 time and global longitudinal strain (r=−0.73, P<0.001). Global contrast-enhanced myocardial T1 time was the strongest independent determinant of global longitudinal strain on multivariate analysis (standardized &bgr;=−0.626, P<0.001). Similarly, there was good correlation between global contrast-enhanced myocardial T1 time and septal E′ (r=0.54, P<0.001). Global contrast-enhanced myocardial T1 time was also the strongest independent determinant of septal E′ (standardized &bgr;=0.432, P<0.001). Conclusions— A shorter global contrast-enhanced myocardial T1 time was associated with more impaired longitudinal myocardial systolic and diastolic function in diabetic patients.

Quantitative assessment of mitral regurgitation: comparison between three-dimensional transesophageal echocardiography and magnetic resonance imaging.

Background— Quantification of mitral regurgitation severity with 2-dimensional (2D) imaging techniques remains challenging. The present study compared the accuracy of 2D transesophageal echocardiography (TEE) and 3-dimensional (3D) TEE for quantification of mitral regurgitation, using MRI as the reference method. Methods and Results— Two-dimensional and 3D TEE and cardiac MRI were performed in 30 patients with mitral regurgitation. Mitral effective regurgitant orifice area (EROA) and regurgitant volume (Rvol) were estimated with 2D and 3D TEE. With 3D TEE, EROA was calculated using planimetry of the color Doppler flow from en face views and Rvol was derived by multiplying the EROA by the velocity time integral of the regurgitant jet. Finally, using MRI, mitral Rvol was quantified by subtracting the aortic flow volume from left ventricular stroke volume. Compared with 3D TEE, 2D TEE underestimated the EROA by a mean of 0.13 cm2. In addition, 2D TEE underestimated the Rvol by 21.6% when compared with 3D TEE and by 21.3% when compared with MRI. In contrast, 3D TEE underestimated the Rvol by only 1.2% when compared with MRI. Finally, one third of the patients in grade 1 and ≥50% of the patients in grade 2 and 3, as assessed with 2D TEE, would have been upgraded to a more severe grade, based on the 3D TEE and MRI measurements. Conclusions— Quantification of mitral EROA and Rvol with 3D TEE is feasible and accurate as compared with MRI and results in less underestimation of the Rvol as compared with 2D TEE.Background—Quantification of mitral regurgitation severity with 2-dimensional (2D) imaging techniques remains challenging. The present study compared the accuracy of 2D transesophageal echocardiography (TEE) and 3-dimensional (3D) TEE for quantification of mitral regurgitation, using MRI as the reference method. Methods and Results—Two-dimensional and 3D TEE and cardiac MRI were performed in 30 patients with mitral regurgitation. Mitral effective regurgitant orifice area (EROA) and regurgitant volume (Rvol) were estimated with 2D and 3D TEE. With 3D TEE, EROA was calculated using planimetry of the color Doppler flow from en face views and Rvol was derived by multiplying the EROA by the velocity time integral of the regurgitant jet. Finally, using MRI, mitral Rvol was quantified by subtracting the aortic flow volume from left ventricular stroke volume. Compared with 3D TEE, 2D TEE underestimated the EROA by a mean of 0.13 cm2. In addition, 2D TEE underestimated the Rvol by 21.6% when compared with 3D TEE and by 21.3% when compared with MRI. In contrast, 3D TEE underestimated the Rvol by only 1.2% when compared with MRI. Finally, one third of the patients in grade 1 and ≥50% of the patients in grade 2 and 3, as assessed with 2D TEE, would have been upgraded to a more severe grade, based on the 3D TEE and MRI measurements. Conclusions—Quantification of mitral EROA and Rvol with 3D TEE is feasible and accurate as compared with MRI and results in less underestimation of the Rvol as compared with 2D TEE.