Ventricular Outflow Tract Area Research Articles

Transcatheter Myotomy to Relieve Left Ventricular Outflow Tract Obstruction: The Septal Scoring Along the Midline Endocardium Procedure in Animals.

Left ventricular outflow tract obstruction complicates hypertrophic cardiomyopathy and transcatheter mitral valve replacement. Septal reduction therapies including surgical myectomy and alcohol septal ablation are limited by surgical morbidity or coronary anatomy and high pacemaker rates, respectively. We developed a novel transcatheter procedure, mimicking surgical myotomy, called Septal Scoring Along the Midline Endocardium (SESAME). SESAME was performed in 5 naive pigs and 5 pigs with percutaneous aortic banding-induced left ventricular hypertrophy. Fluoroscopy and intracardiac echocardiography guided the procedures. Coronary guiding catheters and guidewires were used to mechanically enter the basal interventricular septum. Imparting a tip bend to the guidewire enabled intramyocardial navigation with multiple df. The guidewire trajectory determined the geometry of SESAME myotomy. The myocardium was lacerated using transcatheter electrosurgery. Cardiac function and tissue characteristics were assessed by cardiac magnetic resonance at baseline, postprocedure, and at 7- or 30-day follow-up. SESAME myotomy along the intended trajectory was achieved in all animals. The myocardium splayed after laceration, increasing left ventricular outflow tract area (753 to 854 mm2, P=0.008). Two naive pigs developed ventricular septal defects due to excessively deep lacerations in thin baseline septa. No hypertrophy model pig, with increased septal thickness and left ventricular mass compared with naive pigs, developed ventricular septal defects. One animal developed left axis deviation on ECG but no higher conduction block was seen in any animal. Coronary artery branches were intact on angiography with no infarction on cardiac magnetic resonance late gadolinium imaging. Cardiac magnetic resonance chamber volumes, function, flow, and global strain were preserved. No myocardial edema was evident on cardiac magnetic resonance T1 mapping. This preclinical study demonstrated feasibility of SESAME, a novel transcatheter myotomy to relieve left ventricular outflow tract obstruction. This percutaneous procedure using available devices, with a safe surgical precedent, is readily translatable into patients.

Predicting permanent pacemaker implantation following transcatheter aortic valve replacement: A contemporary meta-analysis of 981,168 patients.

BackgroundHeart block requiring permanent pacemaker (PPM) implantation is a relatively frequent complication of transcatheter aortic valve replacement (TAVR).ObjectiveThe purpose of this study was to perform a contemporary meta-analysis to provide an updated assessment of clinically useful predictors of PPM implantation post-TAVR.MethodsMedline and EMBASE searches were performed to include all studies reporting PPM post-TAVR between 2015 and 2020. Pertinent data were extracted from the studies for further analysis. RevMan was used to create forest plots and calculate risk ratios (RRs).ResultsWe evaluated 41 variables from 239 studies with a total of 981,168 patients. From this cohort, 17.4% received a PPM following TAVR. Strong predictors for PPM implant were right bundle branch block (RBBB) (RR 3.12; P <.001) and bifascicular block (RR 2.40; P = .002). Intermediate factors were chronic kidney disease (CKD) (RR 1.53; P <.0001) and first-degree atrioventricular block (FDAVB) (RR 1.44; P <.001). Weak factors (RR 1–1.50; P <.05) were male gender, age ≥80 years, body mass index ≥25, diabetes mellitus (DM), atrial fibrillation (AF), and left anterior fascicular block (LAFB). These factors along with increased left ventricular outflow tract (LVOT) area (>435 mm2) and/or aortic annulus diameter (>24.4 mm) were incorporated to propose a new scoring system to stratify patients into high- and low-risk groups.ConclusionMale gender, age ≥80 years, FDAVB, RBBB, AF, DM, CKD, Medtronic CoreValve, transfemoral TAVR, increased LVOT, and aortic annulus diameter were significant predictors of post-TAVR PPM implantation. Preprocedural assessment should consider these factors to guide clinical decision-making before TAVR. Validation of our scoring system is warranted.

D-3 | Association of Relative Left Ventricular Outflow Tract Area During Systole with Post-transcatheter Aortic Valve Implantation Insufficiency

Valve selection in transcatheter aortic valve implantation (TAVI) relies on aortic annular sizing. The left ventricular outflow tract (LVOT) may impact the presence of aortic insufficiency (AI) after TAVI, but is not routinely measured. We evaluated distribution of relative LVOT area and association with post-TAVI AI.

Valvular changes after aortic valve neo-cuspidization in children: A case series.

Aortic valve neo-cuspidization (AVNeo), a procedure wherein the aortic valve is reconstructed utilizing an autologous pericardium, has recently been more commonly performed in children. However, the postoperative morphological changes in the aortic valve of pediatric patients remain unknown. The current study aimed to describe the intraoperative and postoperative findings of aortic regurgitation (AR) and stenosis (AS) after AVNeo in children. This case series describes the morphological changes in AR and AS, and their severity, between the perioperative period and 3 months postoperative period after AVNeo in children (<18 years) who underwent AVNeo between April 2016 and March 2020. Data were collected at two measurement points: (i) intraoperative transesophageal echocardiography after weaning from cardiopulmonary bypass (io-TEE); (ii) postoperative transthoracic echocardiography 3 months after the procedure (po-TTE). Seven patients were included in this case series. The number of postoperative AR sites and the ratio of AR jet area to the left ventricular outflow tract area showed a tendency to decrease between io-TEE and po-TTE. All AR sites were integrated during the postoperative period. One patient identified developed intraoperative AS, which maintained its severity after AVNeo. Most cases exhibited spontaneous improvement in AR, while one developed postoperative AS. Further prospective investigation is, therefore, needed to explore surgical outcomes following AVNeo among children.

Impact of Annular Oversizing on Paravalvular Regurgitation and ValveHemodynamics: New Insights From PARTNER 3.

This study sought to investigate the impact of computed tomography (CT)-based area and perimeter oversizing on the incidence of paravalvular regurgitation (PVR) and valve hemodynamics in patients treated with the SAPIEN 3 transcatheter heart valve (THV). The incremental value of considering annular perimeter or left ventricular outflow tract measurements and the impact of THV oversizing on valve hemodynamics are not well defined. The PARTNER 3 (Placement of Aortic Transcatheter Valves 3) trial included 495 low-surgical-risk patients with severe aortic stenosis who underwent THV implantation. THV sizing was based on annular area assessed by CT. Area- and perimeter-based oversizing was determined using systolic annular CT dimensions and nominal dimensions of the implanted THV. PVR, effective orifice area, and mean gradient were assessed on 30-day transthoracic echocardiography. Of 485 patients with available CT and echocardiography data, mean oversizing was 7.9 ± 8.7% for the annulus area and 2.1 ± 4.1% for the perimeter. A very low incidence of≥moderate PVR (0.6%) was observed, including patients with minimal annular oversizing. Incidence of≥mild PVR and need for procedural post-dilatation were inversely related to the degree of oversizing. For patients with annular dimensions suitable for 2 THV sizes, the larger THV with both area and perimeter oversizing was associated with the lowest incidence of≥mild PVR (12.0% vs 43.4%; P<0.0001). Left ventricular outflow tract area oversizing was not associated with PVR. THV prosthesis size, rather than degree of oversizing, had greatest impact on effective orifice area and mean gradient. In low-surgical-risk patients, a low incidence of≥moderate PVR was observed, including patients with minimal THV oversizing. The degree of prosthesis oversizing had the greatest impact on reducing mild PVR and incidence of post-dilatation, without impacting valve hemodynamics. In selected patients with annular dimensions in between 2 valve sizes, the larger THV device oversized to both the annular area and perimeter reduced PVR and optimized THV hemodynamics.

Transesophageal Echocardiographic Assessment of Left Ventricular Outflow Tract Area by 2-Dimensional Diameter, Biplane Planimetry, and 3-Dimensional Planimetry and Its Implications: “Thinking Outside the Circle”

Transesophageal Echocardiographic Assessment of Left Ventricular Outflow Tract Area by 2-Dimensional Diameter, Biplane Planimetry, and 3-Dimensional Planimetry and Its Implications: “Thinking Outside the Circle”

Analysis of left ventricular function, left ventricular outflow tract and aortic valve area using computed tomography: Influence of reconstruction parameters on measurement accuracy.

Objectives:Computed tomography (CT) allows reproducible assessment of left ventricular (LV) function, left ventricular outflow tract area (LVOTarea) and aortic valve area (AVA). We evaluated the influence of image reconstruction parameters on these measurements.Methods:We analyzed 45 contrast-enhanced, retrospectively ECG-gated CT datasets acquired on a third-generation dual source system. A standard filtered-back-projection data set (20 cardiac phases (5% steps, 0–95%), 0.6-mm-slice thickness, 512 × 512 matrix) and eight reconstructions with modified slice thickness (1–8 mm), number of cardiac phases (5, 10), matrix size (256×256) and an iterative reconstruction (IR) algorithm were obtained. LV parameters (ejection fraction (EF), stroke volume (SV), end-diastolic (EDV), end-systolic volumes (ESV)), LVOTarea and AVA were assessed.Results:Differences in LV parameters, LVOTarea and AVA, were only minimal between standard reconstructions and those with modified matrix size, IR algorithm and ≤2 mm slice thickness, while reconstructions with 8-mm slice thickness significantly overestimated SV (p < 0.001) and EDV (p = 0.016). AVA planimetry in reconstructions with ≥5 mm slice thickness was not feasible in 56% of patients. A decrease in the number of reconstructed phases (10 or 5) underestimated EF, SV, EDV, LVOTarea and AVA and overestimated ESV.Conclusions:Modifications of reconstruction parameters (except a slice thickness ≤2 mm) have only a marginal effect on LV, LVOTarea and AVA assessment. However, a reduced number of reconstructions per cardiac cycle may significantly influence measurements.Advances in knowledge:Substantial modifications in number of reconstructions per cardiac cycle significantly affect the assessment of LV function, LVOTarea and AVA also in modern CT scanners.

Left ventricular outflow tract area after percutaneous transseptal transcatheter mitral valve implantation: A three‐dimensional transesophageal echocardiography study

Left ventricular (LV) outflow tract (LVOT) obstruction increases mortality in patients undergoing transcatheter mitral valve implantation (TMVI) in degenerated bioprostheses, annuloplasty rings, and native mitral valves. We aimed to evaluate the LVOT area after TMVI using 3-dimensional (3D) transesophageal echocardiography (TEE) and to investigate the preprocedural cardiac geometry that affects the LVOT area after TMVI. We retrospectively reviewed echocardiography data in 43 patients who had TMVI. A change in pressure gradient across LVOT from before to after TMVI (∆PG) and postprocedure 3D LVOT cross-sectional area at the level of the most distal portion of the mitral valve stent that was closest to the LV apex were assessed as evidence of LVOT narrowing. Transcatheter mitral valve implantation with the use of balloon-expandable valve system was performed for 24 bioprostheses, 7 annuloplasty rings, and 12 native valves. Compared to patients without increase in LVOT gradient (∆PG <10mm Hg; n=33), patients with increase in LVOT gradient (∆PG ≥10mm Hg; n=10) had smaller LV end-systolic volume (LVESV), greater LV ejection fraction (LVEF), and smaller aorto-mitral (AM) angle. The LVOT area at the valve stent distal edge showed strong association with ∆PG (r=-.68, P<.0001). Only a small AM angle was associated with a small LVOT area at the valve stent distal edge on multivariable analysis, independent of LVESV and LVEF. Small LV size, preserved LVEF, and small AM angle were associated with LVOT narrowing. 3D-derived AM angle might be independently associated with LVOT narrowing in patients undergoing transcatheter mitral valve-in-valve, valve-in-ring, and valve-in-native valve implantation, independent of LVESV and LVEF.

Assessment of the left ventricular outflow tract during cardiac anaesthesia with biplane transoesophageal echocardiography: An observational study.

Assessment of left ventricular outflow tract (LVOT) area is a key component of quantification of aortic stenosis and stroke volume. Current international guidelines recommend measurement of the LVOT diameter with two-dimensional (2D) echocardiography and assume a circle. This may lead to erroneous measures of aortic valve area and adversely affect peri-operative decision making. Multiplane orthogonal (biplane) and three-dimensional (3D) echocardiography imaging may allow more accurate calculation of LVOT, aortic valve area and stroke volume. To evaluate the shape and area of the LVOT with conventional 2D diameter, short axis cross-sectional planimetry with biplane imaging and 3D multiplane reconstruction in patients undergoing cardiac surgery with transoesophageal echocardiography (TOE). A retrospective observational study. A single centre university hospital. 119 patients undergoing cardiac surgery with TOE. None. Measurements of the shape and area of the LVOT with standard 2D TOE, short axis biplane imaging and 3D TOE. The LVOT shape is elliptical in 70% of patients. The (mean ± SD, [range]) LVOT cross-sectional area with 2D TOE was 4.29 cm2 ± 0.98, [2.46 to 6.70], with biplane was 4.68 cm2 ± 1.03, [2.92 to 7.30] and with 3D was 4.59 cm2 ± 0.99, [2.78 to 7.10]. There was a statistically significant difference (P < 0.001) in the three pairwise comparisons. 2D LVOT area had large bias (7 to 9%) and wider limits of agreement (LOA) with both biplane and 3D LVOT area (-17 to 36%). Biplane and 3D LVOT areas had small bias (1.8%) with relatively narrow LOA (-8 to 11%). 2D diameter measures of the LVOT assuming a circle underestimate LVOT area, underestimate aortic valve area and increase the apparent severity of aortic stenosis. This may lead to inappropriate aortic valve intervention. In a busy operating room environment, we suggest that for the calculation of stroke volume and aortic valve area, LVOT area is measured with biplane imaging. Observational study with no interventions so trial not registered.

Prosthesis-patient mismatch defined by cardiac computed tomography versus echocardiography after transcatheter aortic valve replacement

BackgroundsEvaluation of prosthesis-patient mismatch (P-PM) after transcatheter aortic valve replacement (TAVR) by transthoracic echocardiography (TTE) has provided conflicting results regarding its impact on outcomes. Whether post-TAVR computed tomography angiography (CTA) evaluation of P-PM can improve our understanding is unknown. We aimed to evaluate the inter-modality (TTE vs. CTA) agreement, inter-valve platform (balloon-expanding valve [BEV] vs. self-expandable valve [SEV]) differences in P-PM severity, and outcomes related to P-PM after TAVR. MethodsWe analyzed patients with both CTA and TTE before and after TAVR. Indexed effective orifice area was calculated using two methods: TTE-derived left ventricular outflow tract (LVOT) area from measured diameter and post-TAVR CTA-measured area. Body size specific cut-offs for P-PM severity were used: for body mass index (BMI) ​< ​30 ​kg/m2, moderate ​= ​0.66–0.85 ​cm2/m2 and severe≤0.65 ​cm2/m2; for BMI ≥30 ​kg/m2, moderate ​= ​0.56–0.70 ​cm2/m2 and severe≤0.55 ​cm2/m2. ResultsA total of 447 patients were included (median age, 83 years; 54% male). The prevalence of P-PM (moderate or severe) was lower with CTA vs. TTE (3.5% vs. 19.5%, p ​< ​0.001). The prevalence of P-PM measured by TTE was more common in BEV compared to SEV (p ​= ​0.002), while CTA assessment showed no difference in P-PM incidence and severity between TAVR platforms (p ​= ​0.40). In multivariable analysis, CTA-defined but not TTE-defined P-PM was associated with mortality after TAVR (HR:3.97; 95%CI,1.55–10.2; p ​= ​0.004). Both CTA-defined and TTE-defined P-PM were associated with the composite of death and heart failure rehospitalization. ConclusionAlthough post-TAVR CTA substantially downgraded the prevalence of P-PM compared to TTE, it identified a subset of patients with clinically relevant P-PM which associated with outcomes.

Association Between Three-Dimensional Left Ventricular Outflow Tract Area and Gradients After Myectomy in Hypertrophic Obstructive Cardiomyopathy

Determine whether the intraoperative three-dimensional left ventricular outflow tract cross-sectional area may be inversely correlated with pressure gradients as a determinant of surgical success after septal myectomy in hypertrophic cardiomyopathy patients. Perioperative data were obtained by retrospective review. Toronto General Hospital, University of Toronto, Toronto, Canada, a tertiary hospital. The study comprised 67 patients with hypertrophic obstructive cardiomyopathy. Transthoracic and intraoperative transesophageal echocardiographic assessment of pressure gradients. Transesophageal measurement of the three-dimensional left ventricular outflow tract cross-sectional area. The smallest left ventricular outflow tract area increased on average 1.883 cm2 (98.3%) after septal myectomy. There was a significant correlation between the increase in the area and the transesophageal pressure gradients (r = -0.32; p = 0.01) after myectomy, but none with postoperative transthoracic gradients at rest (r = -0.10; p = 0.42). Postoperative transesophageal and transthoracic gradients were significantly correlated (r = 0.26; p = 0.04). The best risk factors to predict high residual gradients were preoperative transesophageal gradient >97 mmHg, postoperative transesophageal area <3.16 cm2, and moderate or more residual transesophageal mitral regurgitation (specificity 89%, 81%, and 78%, respectively). Three-dimensional left ventricular outflow tract area measurements with transesophageal echocardiography after myectomy correlated fairly well with postoperative transesophageal pressure gradients. Patients with residual transthoracic elevated gradients after surgery at follow-up had a smaller transesophageal area and higher transesophageal pressure gradients immediately after the procedure. However, transesophageal pressure gradients after myectomy correlated poorly with follow-up transthoracic gradients at rest.

Reclassification of aortic stenosis by fusion of echocardiography and computed tomography in low-gradient aortic stenosis.

BackgroundThe integration of computed tomography (CT)-derived left ventricular outflow tract area into the echocardiography-derived continuity equation results in the reclassification of a significant proportion of patients with severe aortic stenosis (AS) into moderate AS based on aortic valve area indexed to body surface area determined by fusion imaging (fusion AVAi). The aim of this study was to evaluate AS severity by a fusion imaging technique in patients with low-gradient AS and to compare the clinical impact of reclassified moderate AS versus severe AS.MethodsWe included 359 consecutive patients who underwent transcatheter aortic valve implantation for low-gradient, severe AS at two academic institutions and created a joint database. The primary endpoint was a composite of all-cause mortality and rehospitalisations for heart failure at 1 year.ResultsOverall, 35% of the population (n = 126) were reclassified to moderate AS [median fusion AVAi 0.70 (interquartile range, IQR 0.65–0.80) cm2/m2] and severe AS was retained as the classification in 65% [median fusion AVAi 0.49 (IQR 0.43–0.54) cm2/m2]. Lower body mass index, higher logistic EuroSCORE and larger aortic dimensions characterised patients reclassified to moderate AS. Overall, 57% of patients had a left ventricular ejection fraction (LVEF) <50%. Clinical outcome was similar in patients with reclassified moderate or severe AS. Among patients reclassified to moderate AS, non-cardiac mortality was higher in those with LVEF <50% than in those with LVEF ≥50% (log-rank p = 0.029).ConclusionsThe integration of CT and transthoracic echocardiography to obtain fusion AVAi led to the reclassification of one third of patients with low-gradient AS to moderate AS. Reclassification did not affect clinical outcome, although patients reclassified to moderate AS with a LVEF <50% had worse outcomes owing to excess non-cardiac mortality.

Aortic valve area calculation using 3D transesophageal echocardiography: Implications for aortic stenosis severity grading.

Aortic stenosis (AS) grading by 2D-transthoracic echocardiography (2D-TTE) aortic valve area (AVA) calculation is limited by left ventricular outflow tract (LVOT) area underestimation. The combination of Doppler parameters with 3D LVOT area obtained by multidetector computed tomography (MDCT) can improve AS grading, reconciling discordant 2D-TTE findings. This study aimed to systematically evaluate the role of 3D-transesophageal echocardiography (3D-TEE) in AS grading using MDCT as reference standard. 288 patients (81±6.3years, 52.4% female) with symptomatic AS underwent 2D-TTE, 3D-TEE, and MDCT for transcatheter aortic valve implantation. Doppler parameters were combined with 3D LVOT areas measured by manual and semi-automated software 3D-TEE and by MDCT to calculate AVA, reassessing AS severity. Both 3D-TEE modalities demonstrated good correlation with MDCT, with excellent intra-observer and inter-observer variability. Compared to MDCT, 3D-TEE measurements significantly underestimated AVA (PANOVA <.0001), although the difference was clinically acceptable. Compared to 2D-TTE, 3D-TEE manual and semi-automated software reclassified severe AS in 21.9% and 25.2% of cases, respectively (P<.0001), overcame grading parameters discordance in more than 40% of cases in patients with low-gradient AS (P<.0001) and reduced the proportion of low-flow states in nearly 75% of cases when combined to stroke volume index assessment (P<.0001). 3D-TEE imaging modalities showed a reduction in the proportion of patients with low-gradient and pathological AVA as defined by 2D-TTE, and improved AVA and mean pressure gradient agreement with current guidelines cutoff values. 3D-TEE AVA calculation is a reliable tool for AS grading with excellent reproducibility and good correlation with MDCT measurements.

A pairwise meta-analytic comparison of aortic valve area determined by planimetric versus hemodynamic methods in aortic stenosis

BackgroundAortic valve area (AVA) is commonly determined from 2-dimensional transthoracic echocardiography (2D TTE) by the continuity equation; however, this method relies on geometric assumptions of the left ventricular outflow tract which may not hold true. This study compared mean differences and correlations for AVA by planimetric (2-dimensional transesophageal echocardiography [2D TEE], 3-dimensional transesophageal echocardiography [3D TEE], 3-dimensional transthoracic echocardiography [3D TTE], multi-detector computed tomography [MDCT], and magnetic resonance imaging [MRI]) with hemodynamic methods (2D TTE and catheterization) using pairwise meta-analysis. MethodOvid MEDLINE®, Ovid EMBASE, and The Cochrane Library (Wiley) were queried for studies comparing AVA measurements assessed by planimetric and hemodynamic techniques. Pairwise meta-analysis for mean differences (using random effect model) and for correlation coefficients (r) were performed. ResultsForty-five studies (3014 patients) were included. Mean differences between planimetric and hemodynamic techniques were 0.12 cm2 (95%CI 0.10–0.15) for AVA (pooled r = 0.84; 95%CI 0.76–0.90); 1.36cm2 (95%CI 1.03–1.69) for left ventricular outflow tract area; and 0.13 cm (95%CI 0.07–0.20) for annular diameter (pooled r = 0.76; 95% CI 0.64–0.94); 0.67 cm2 (95%CI 0.59–0.76) for annular area (pooled r = 0.74; 95%CI 0.55–0.86). ConclusionsPlanimetric techniques slightly, but significantly, overestimate AVA when compared to hemodynamic techniques.

Two- or 3-Dimensional Echocardiography–Derived Cardiac Output Cannot Replace the Pulmonary Artery Catheter in Cardiac Surgery

Three-dimensional (3D) transesophageal echocardiography (TEE) has been shown to be more accurate than 2D TEE for the evaluation of the left ventricular outflow tract area. The aim of the present study was to compare the agreement of 3D echocardiography-derived cardiac output (CO) with thermodilution-derived CO (TDCO) before and after cardiopulmonary bypass (CPB). This was a prospective observational study of patients who underwent cardiac surgery between 2016 and 2018. Weill Cornell Medicine, a single large academic medical center. The study comprised 78 patients undergoing elective cardiac surgery. CPB, TEE, pulmonary artery catheter, and elective cardiac surgery. Two-dimensional CO, 3D CO-diameter, and 3D CO-area values pre-CPB were strongly correlated with one another both pre-CPB and post-CPB. The 3D CO-diameter and the 3D CO-area were mildly correlated, with TDCO measurements pre-CPB (r = 0.46 and 0.39, respectively) and post-CBP (r = 0.43 and 0.47, respectively). Pre-CPB 3D CO-diameter had the most agreement with TDCO in terms of bias (-0.13 L/min); however, the limits of agreement (LOA) were wide (-2.2- to- 2.45 L/min). Post-CPB, 3D CO-diameter had the most agreement with TDCO in terms of bias (0.41) but with wide LOA (-3.29 to 2.47). All pre-CPB echocardiography-derived CO (2D CO, 3D CO-diameter, 3D CO-area) had more agreement with TDCO than did post-CPB measurements. Three-dimensional CO measurements were only modestly correlated with pulmonary artery catheter-derived CO pre-bypass and post-bypass. Despite low bias, the wide LOA from 2D CO, 3D CO-diameter, and 3D-area compared with TDCO suggested that the 2 methods are not interchangeable.

Multimodality imaging derived energy loss index and outcome after transcatheter aortic valve replacement.

To assess whether the combination of transthoracic echocardiography (TTE) and multidetector computed tomography (MDCT) data affects the grading of aortic stenosis (AS) severity under consideration of the energy loss index (ELI) in patients undergoing transcatheter aortic valve replacement (TAVR). Multimodality imaging was performed in 197 patients with symptomatic severe AS undergoing TAVR at the University Hospital Zurich, Switzerland. Fusion aortic valve area index (fusion AVAi) assessed by integrating MDCT derived planimetric left ventricular outflow tract area into the continuity equation was significantly larger as compared to conventional AVAi (0.41 ± 0.1 vs. 0.51 ± 0.1 cm2/m2; P < 0.01). A total of 62 patients (31.4%) were reclassified from severe to moderate AS with fusion AVAi being >0.6 cm2/m2. ELI was obtained for conventional AVAi and fusion AVAi based on sinotubular junction area determined by TTE (ELILTL 0.47 ± 0.1 cm2/m2; fusion ELILTL 0.60 ± 0.1 cm2/m2) and MDCT (ELIMDCT 0.48 ± 0.1 cm2/m2; fusion ELIMDCT 0.61 ± 0.05 cm2/m2). When ELI was calculated with fusion AVAi the effective orifice area was >0.6 cm2/m2 in 85 patients (43.1%). Survival rate 3 years after TAVR was higher in patients reclassified to moderate AS according to multimodality imaging derived ELI (78.8% vs. 67%; P = 0.01). Multimodality imaging derived ELI reclassifies AS severity in 43% undergoing TAVR and predicts mid-term outcome.

Three-dimensional versus two-dimensional transthoracic echocardiography for left ventricular outflow tract measurements in severe aortic stenosis. A cross-sectional study using computer tomography and Haegar sizers as reference

Objectives. In grading of aortic stenosis, two-dimensional transthoracic echocardiography (2D TTE) routinely results in underestimation of the left ventricular outflow tract (LVOT) area, and hence the aortic valve area (AVA). We investigated whether three-dimensional (3D) TTE measurements of the LVOT would be more accurate. We evaluated the feasibility, agreement and inter-observer variability of 3D TTE LVOT measurements with computed tomography (CT) and Haegar sizers as reference. Design. Sixty-one patients with severe aortic stenosis were examined with 2D and 3D TTE. 41 had CT and 13 also had perioperative Haegar sizing. Pearson’s correlation and Bland-Altman plots were used to compare methods. Inter-observer variability was tested for 2D and 3D TTE. Trial registration: Current research information system in Norway (CRISTIN). Id: 555249. Results. Feasibility was 67% with 3D TTE and 100% with 2D TTE and CT. Mean LVOT area for 2D, 3D, CT and Haegar sizers were 3.7 ± 0.6 cm2, 4.0 ± 0.9 cm2, 5.2 ± 0.8 cm2 and 4.4 ± 1.0 cm2 respectively. Bias and limits of agreements for 2D TTE was 1.5 ± 1.3 cm2, compared with CT and 0.4 ± 1.5 cm2 with Haegar sizers. Corresponding results for 3D TTE were 1.2 ± 1.6 cm2 and 0.2 ± 1.8 cm2. Intraclass correlation coefficients for LVOT area were 0.62 for 3D and 0.86 for 2D. Conclusions. 2D TTE showed better feasibility and inter-observer variability in measurements of LVOT than 3D TTE. Both echocardiographic methods underestimated LVOT area compared to CT and Haegar sizers. These observations suggest that 2D TTE is still preferable to 3D TTE in the assessment of aortic stenosis.

Direct Planimetry of Left Ventricular Outflow Tract Area by Simultaneous Biplane Imaging: Challenging the Need for a Circular Assumption of the Left Ventricular Outflow Tract in the Assessment of Aortic Stenosis

Evaluation of aortic stenosis (AS) requires calculation of aortic valve area (AVA), which relies on the assumption of a circular-shaped left ventricular outflow tract (LVOT). However, the LVOT is often elliptical, and the circular assumption underestimates the true LVOT area (LVOTA). Biplane imaging using transthoracic echocardiography allows direct planimetry of LVOTA. The aim of this study was to assess the feasibility of obtaining LVOTA using this technique and its impact on the discordance between AVA and gradient criteria in AS grading. We prospectively studied 134 patients (median age, 80years; interquartile range, 73-87years; 39% women) with AS, including 82 (61%) with severe AS and 52 (39%) with mild or moderate AS. LVOTA was traced using direct planimetry (LVOTAbiplane) and compared with LVOTA calculated using the circular assumption (LVOTAcirc). In a subset of patients who underwent cardiac computed tomography, direct planimetry of LVOTA was used as a reference standard. LVOTAbiplane was significantly larger than LVOTAcirc (4.20cm2 [interquartile range, 3.66-4.90cm2] vs 3.73cm2 [interquartile range, 3.14-4.15cm2], P<.001). Among 30 patients who underwent cardiac computed tomography, LVOTAbiplane had better agreement with LVOTA by direct planimetry than LVOTAcirc (mean bias, -0.45±0.63 vs -1.02±0.63cm2; P<.0001). Of 82 patients with severe AS (AVA≤1cm2 using LVOTAcirc), 40 (49%) had discordant mean gradient (<40mm Hg). By using LVOTAbiplane, patients with discordant AVA and mean gradient decreased from 49% to 27% (P=.004), and 29% of patients with severe AS were reclassified with moderate AS, with the highest percentage of reclassification in the group with low-gradient AS with preserved left ventricular ejection fraction. Direct planimetry using biplane imaging avoids the inherent underestimation of LVOTA using the circular assumption. LVOTA obtained by biplane planimetry can lead to better concordance between AVA and mean gradient and classification of AS severity.

Three-Dimensional Modeling of Surgically Implanted Stent-Based Valves in the Mitral Position in Children

In children with a mitral annulus too small to accommodate traditional prostheses, surgical implantation of stent-based valves is a promising option. However no reliable preoperative methods exist to guide patient selection, device sizing, and positioning. We describe a novel methodology to visualize and quantify device fit in 3-dimensional echocardiogram (3DE)-derived heart models. Heart models were created from existing preoperative 3DEs using custom software. Valve models were virtually implanted into the models, and both device fit and left ventricular outflow tract (LVOT) area were quantified. The 3DEs of 3 patients who underwent Melody valve placement in the mitral position were retrospectively modeled: 1 with LVOT obstruction, 1 with perivalvar leak, and 1 without complications. In all cases 2-dimensional measurements underestimated 3D annular dimensions, and the patient with clinical LVOT obstruction had the lowest predicted LVOT area-to-aortic area ratio (0.5). 3DE-based preoperative modeling of surgical implantation of stent-based valves in the mitral position may improve quantification of mitral valve dimensions and inform risk stratification for potential LVOT obstruction.

CT VERSUS ECHOCARDIOGRAPHIC STROKE VOLUME INDEX COMPARED TO INVASIVELY DERIVED CARDIAC INDEX TO ASSESS FLOW IN PATIENTS WITH AORTIC STENOSIS

Echocardiographic (ECHO)-derived stroke volume index (SVI) is used to define flow state in patients with aortic stenosis (AS) as the product of left ventricular outflow tract (LVOT) area and time velocity integral. CT provides a better assessment of the LVOT area. We sought to determine low flow (LF