Demonstration of left ventricular outflow tract eccentricity by real time 3D echocardiography: implications for the determination of aortic valve area

Impact of the Insoluble Gas Concentration on Measured Stroke Volume at Rest and Submaximal Exercise Using the Innocor Device

INTRODUCTION

The Innocor® device uses an insoluble gas (SF 6 ) to estimate lung volume and the rate of disappearance of a soluble gas (nitrous oxide) to measure pulmonary blood flow (PBF), which approximates cardiac output assuming no shunt. We sought to identify error in the measurement of the insoluble gas in an effort to reduce variation in Innocor® measurement.

METHODS

We enrolled 28 participants from the Dallas Heart Study (mean age, 63 yr; 57% men; 43% White). Stroke volume was measured at rest and at submaximal (20 and 40 W) exercise using both echocardiography (Philips iE33) and the Innocor® device. We defined a priori peak and equilibrium SF 6 measurement errors as greater or less than 20% of the mean observed value. Three Innocor measurements were obtained at rest ( n = 27) for a total of 81 measurements. Of these, 22% had SF 6 measurements that fell outside of the a priori range.

RESULTS

Resting Innocor® stroke volume measures with peak SF 6 measured above a priori range (>0.12%) was associated with larger stroke volumes compared with stroke volume measures without peak SF 6 error (101.4 [26.8] vs 64.9 [8.7] mL; P = 0.006) and overestimated stroke volume when compared with stroke volume by echo (101.4 [26.8] vs 59.9 [16.3] mL; P = 0.017). A similar pattern was observed at submaximal exercise. In contrast, there was no consistent association between variation in equilibrium SF 6 concentrations and measured stroke volume.

CONCLUSIONS

Variability in peak SF 6 concentration is common while using the Innocor® device and results in overestimated stroke volume. These findings have implications for research protocols using this device.

Core Lab Adjudication of the ACURATE neo2 Hemodynamic Performance Using Computed-Tomography-Corrected Left Ventricular Outflow Tract Area

(1) Background: Hemodynamic assessment of prosthetic heart valves using conventional 2D transthoracic Echocardiography-Doppler (2D-TTE) has limitations. Of those, left ventricular outflow tract (LVOT) area measurement is one of the major limitations of the continuity equation, which assumes a circular LVOT. (2) Methods: This study comprised 258 patients with severe aortic stenosis (AS), who were treated with the ACURATE neo2. The LVOT area and its dependent Doppler-derived parameters, including effective orifice area (EOA) and stroke volume (SV), in addition to their indexed values, were calculated from post-TAVI 2D-TTE. In addition, the 3D-LVOT area from pre-procedural MDCT scans was obtained and used to calculate corrected Doppler-derived parameters. The incidence rates of prosthesis patient mismatch (PPM) were compared between the 2D-TTE and MDCT-based methods (3) Results: The main results show that the 2D-TTE measured LVOT is significantly smaller than 3D-MDCT (350.4 ± 62.04 mm² vs. 405.22 ± 81.32 mm²) (95% Credible interval (CrI) of differences: −55.15, −36.09), which resulted in smaller EOA (2.25 ± 0.59 vs. 2.58 ± 0.63 cm²) (Beta = −0.642 (95%CrI of differences: −0.85, −0.43), and lower SV (73.88 ± 21.41 vs. 84.47 ± 22.66 mL), (Beta = −7.29 (95% CrI: −14.45, −0.14)), respectively. PPM incidence appears more frequent with 2D-TTE- than 3D-MDCT-corrected measurements (based on the EOAi) 8.52% vs. 2.32%, respectively. In addition, significant differences regarding the EOA among the three valve sizes (S, M and L) were seen only with the MDCT, but not on 2D-TTE. (4) Conclusions: The corrected continuity equation by combining the 3D-LVOT area from MDCT with the TTE Doppler parameters might provide a more accurate assessment of hemodynamic parameters and PPM diagnosis in patients treated with TAVI. The ACURATE neo2 THV has a large EOA and low incidence of PPM using the 3D-corrected LVOT area than on 2D-TTE. These findings need further confirmation on long-term follow-up and in other studies.

Two wrongs sometimes do make a right: errors in aortic valve stenosis assessment by same-day Doppler echocardiography and 4D flow MRI

This study aims to systematically verify if the simplified geometry and flow profile of the left ventricular outflow tract (LVOT) assumed in 2D echocardiography is appropriate while examining the utility of 4D flow MRI to assess valvular disease. This prospective study obtained same-day Doppler echocardiography and 4D flow MRI in 37 healthy volunteers (age: 51.9 ± 18.2, 20 females) and 7 aortic stenosis (AS) patients (age: 64.2 ± 9.6, 1 female). Two critical assumptions made in echocardiography for aortic valve area assessment were examined, i.e. the assumption of (1) a circular LVOT shape and (2) a flat velocity profile through the LVOT. 3D velocity and shape information obtained with 4D flow MRI was used as comparison. It was found that the LVOT area was lower (by 26.5% and 24.5%) and the velocity time integral (VTI) was higher (by 28.5% and 30.2%) with echo in the healthy and AS group, respectively. These competing errors largely cancelled out when examining individual and cohort averaged LVOT stroke volume. The LVOT area, VTI and stroke volume measured by echo and 4D flow MRI were 3.6 ± 0.7 vs. 4.9 ± 1.0 cm2 (p < 0.001), 21.2 ± 3.0 vs 15.2 ± 2.8 cm (p < 0.001), and 75.6 ± 15.6 vs 72.8 ± 14.1 ml (p = 0.3376), respectively. In the ensemble average of LVOT area and VTI, under- and over-estimation seem to compensate each other to result in a 'realistic' stroke volume. However, it is important to understand that this compensation may fail. 4D flow MRI provides a unique insight into this phenomenon.

Is There a Correlation Between Left Ventricular Outflow Tract Velocity Time Integral and Stroke Volume Index in Patients Undergoing Cardiac Surgery?

Introduction

Left ventricular outflow tract velocity time integral (LVOT VTI) is a promising surrogate for stroke volume (SV). However, there is controversy in the literature regarding its correlation with thermodilution or newer cardiac output measurement techniques. This study was conducted to determine the correlation between LVOT VTI determined by transesophageal echocardiography (TEE) with stroke volume index (SVI) calculated by thermodilution.

Methods

Consecutive patients older than 17 years undergoing elective cardiac surgery with pulmonary artery catheter (PAC) and TEE monitoring between September 2021 and February 2022 were included in this prospective, descriptive, single-center study. LVOT VTI was measured using TEE after induction of anesthesia but before skin incision and at least four hours after initial LVOT VTI measurement. SVI was simultaneously measured using the continuous thermodilution technique with a PAC. The correlation between LVOT VTI and SVI was determined with Pearson’s correlation index.

Results

Twelve patients were included and 21 paired measurements were compared. Mean SVI was 31.62 ± 10.71 mL/m² and mean LVOT VTI was 14.74 ± 4.79 cm. The Pearson's correlation index for the two measurements was r = 0.257, p = 0.262.

Conclusion

This prospective study demonstrated a weak correlation between LVOT VTI and SVI in patients undergoing cardiac surgery.

Calculation of Aortic VAlve and LVOT Areas by a Modified Continuity Equation Using Different Echocardiography Methods: The CAVALIER Study

Background: The area of the left ventricular outflow tract (A_LVOT) represents a major component of the continuity equation (CE), which is, i.a., crucial to calculate the aortic valve (AV) area (A_AV). The A_LVOT is typically calculated using 2D echo assessments as the measured anterior–posterior (a/p) extension, assuming a round LVOT base. Anatomically, however, usually an elliptical shape of the LVOT base is present, with the long diameter extending from the medial–lateral axis (m/l), which is not recognized by two-dimensional (2D) echocardiography. Objective: We aimed to compare standard and three-dimensional (3D)-echocardiography-derived A_LVOT calculation and its use in a standard CE (CE_std) and a modified CE (CE_mod) to calculate the A_AV vs. computed tomography (CT) multi-planar reconstruction (MPR) measurements of the anatomical A_LVOT, and A_AV, respectively. Methods: Patients were selected if 3D transthoracic echocardiography (TTE), 3D transesophageal echocardiography (TEE), and cardiac CT were all performed, and imaging quality was adequate. The A_LVOT was assessed using 2D calculation, (a/p only), 3D-volume MPR, and 3D-biplane calculation (a/p and m/l). A_AV was measured using both CE_std and CE_mod, and 3D-volume MPR. Data were compared to corresponding CT analyses. Results: From 2017 to 2018, 107 consecutive patients with complete and adequate imaging data were included. The calculated A_LVOT was smaller when assessed by 2D- compared to both 3D-volume MPR and 3D-biplane calculation. Calculated A_AV was correspondingly smaller in CE_std compared to CE_mod or 3D-volume MPR. The A_LVOT and A_AV, using data from 3D echocardiography, highly correlated and were congruent with corresponding measurements in CT. Conclusion: Due to the elliptic shape of the LVOT, use of measurements and calculations based on 2D echocardiography systematically underestimates the A_LVOT and dependent areas, such as the A_AV. Anatomically correct assessment can be achieved using 3D echocardiography and adapted calculations, such as CE_mod.

Comparison of Simultaneous Transthoracic Versus Transesophageal Echocardiography for Assessment of Aortic Stenosis

Transthoracic echocardiography (TTE) is the gold standard for aortic stenosis (AS) assessment. Transesophageal echocardiography (TEE) provides better resolution, but its effect on AS assessment is unclear. To answer this question, we studied 56 patients with ≥moderate AS. Initial TTE (TTE1) was followed by conscious sedation with simultaneous TEE and TTE2. Based on conservative versus actionable implication, AS types were dichotomized into group A, comprising moderate and normal-flow low-gradient, and group B, comprising high gradient, low ejection fraction low-flow low-gradient, and paradoxical low-flow low-gradient AS. Paired analysis of echocardiographic variables and AS types measured by TEE versus TTE2 and by TEE versus TTE1 was performed. TEE versus simultaneous TTE2 comparison demonstrated higher mean gradients (31.7 ± 10.5 vs 27.4 ± 10.5 mm Hg) and velocities (359 ± 60.6 vs 332 ± 63.1 cm/s) with TEE, but lower left ventricular outflow velocity-time-integral (VTI₁) (18.6 ± 5.1 vs 20.2 ± 6.1 cm), all p <0.001. This resulted in a lower aortic valve area (0.8 ± 0.21 vs 0.87 ± 0.28 cm²), p <0.001, and a net relative risk of 1.86 of group A to B upgrade. TEE versus (awake state) TTE1 comparison revealed a larger decrease in VTI₁ because of a higher initial awake state VTI₁ (22 ± 5.6 cm), resulting in similar Doppler-velocity-index and aortic valve area decrease with TEE, despite a slight increase in mean gradients of 0.8 mm Hg (confidence interval -1.44 to 3.04) and velocities of 10 cm/s (confidence interval -1.5 to 23.4). This translated into a net relative risk of 1.92 of group A to B upgrade versus TTE1. In conclusion, TEE under conscious sedation overestimates AS severity compared with both awake state TTE and simultaneous sedation state TTE, accounted for by different Doppler insonation angles obtained in transapical versus transgastric position.

Comparison of the effective orifice area of prosthetic mitral valves using two-dimensional versus three-dimensional transesophageal echocardiography

Objective

This study compared the continuity equation-based effective orifice area (EOA) of prosthetic mitral valves between two-dimensional (2D) and 3D transesophageal echocardiography (TEE).

Methods

Thirty-four patients without major aortic valve abnormalities underwent mitral valve replacement surgery. The EOAs of prosthetic mitral valves were calculated using the continuity equation with 2D and 3D TEE. For 18/34 patients using a biological valve prosthesis, the EOA of the prosthesis was obtained from commercial records.

Results

The EOA of prosthetic mitral valves significantly varied between the 2D and 3D methods (2.22 ± 0.71 vs 2.35 ± 0.70 cm², n = 34). The area of the diameter of the left ventricular outflow tract as determined by the 3D method was significantly higher than that by the 2D method (mean difference: −0.14 ± 0.20 cm²), with 95% coherence boundaries of −0.53 and 0.25 cm². The regression equation for the EOA by 3D and 2D TEE was y = 0.27 + 0.94x, with a good correlation.

Conclusions

The EOA of prosthetic mitral valves is underestimated using the 2D TEE method compared with the 3D TEE method. The 3D-TEE method has the advantage of higher precision over the 2D TEE method, and it may be helpful for better assessment of prosthetic mitral valves intraoperatively.

Association between multimodality measures of aortic stenosis severity and quality-of-life improvement outcomes after transcatheter aortic valve replacement

AIMS

Up to 40% of patients with aortic stenosis (AS) present with discordant grading of AS severity based on common transthoracic echocardiography (TTE) measures. Our aim was to evaluate the utility of TTE and multi-detector computed tomography (MDCT) measures in predicting symptomatic improvement in patients with AS undergoing transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

A retrospective review of 201 TAVR patients from January 2017 to November 2018 was performed. Pre- and post-intervention quality-of-life was measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ-12). Pre-intervention measures including dimensionless index (DI), stroke volume index (SVI), mean transaortic gradient, peak transaortic velocity, indexed aortic valve area (AVA), aortic valve calcium score, and AVA based on hybrid MDCT-Doppler calculations were obtained and correlated with change in KCCQ-12 at 30-day follow-up. Among the 201 patients studied, median KCCQ-12 improved from 54.2 pre-intervention to 85.9 post-intervention. In multivariable analysis, patients with a mean gradient >40 mmHg experienced significantly greater improvement in KCCQ-12 at follow-up than those with mean gradient ≤40 mmHg (28.1 vs. 16.4, P = 0.015). Patients with MDCT-Doppler-calculated AVA of ≤1.2 cm2 had greater improvements in KCCQ-12 scores than those with computed tomography-measured AVA of >1.2 cm2 (23.4 vs. 14.1, P = 0.049) on univariate but not multivariable analysis. No association was detected between DI, SVI, peak velocity, calcium score, or AVA index and change in KCCQ-12.

CONCLUSION

Mean transaortic gradient is predictive of improvement in quality-of-life after TAVR. This measure of AS severity may warrant greater relative consideration when selecting the appropriateness of patients for TAVR.

[Consistency of effective orifice area of prosthetic mitral valve estimated using 2-dimensional and 3-dimensional transesophageal echocardiography]

OBJECTIVE

To analyze the consistency of effective orifice area (EOA) of prosthetic mitral valve estimated using 2- dimensional (2D) and 3-dimensional (3D) transesophageal echocardiography (TEE).

OBJECTIVE

This study was conducted among 34 patients undergoing mitral valve replacement surgery in Nanjing First Hospital between March and June in 2019. The diameter of the left ventricular outflow tract (LVOT) measured by 2D-TEE was used to calculate the cross sectional area of LVOT (CSALVOT). In 3D-TEE method, LVOT area was measured directly by planimetry on an enface view. The EOAs of the prosthetic mitral valve were calculated for both methods using the continuity equation. Bland-Altman plot consistency test was used to analyze the consistency between the two sets of EOA results, and linear regression analysis was used to analyze their correlation.

OBJECTIVE

The EOA of the prosthetic mitral valve differed significantly between 2D method and 3D method (2.22±0.71 cm² vs 2.35±0.70 cm², P < 0.001) with a mean difference of -0.14±0.20 cm² and 95% coherence boundaries of (-0.53, 0.25 cm²). The regression equation for EOA-3D and EOA-2D is y=0.27 + 0.94x, showing a good correlation between the two methods.

OBJECTIVE

EOA estimation of the prosthetic mitral valve using 2D and 3D TEE has a good consistency, and the results estimated by the 2D method are slightly lower by about 6% than those by the 3D method.

Assessment of left ventricular outflow tract and aortic root: comparison of 2D and 3D transthoracic echocardiography with multidetector computed tomography

AIMS

Accurate echocardiographic assessment of left ventricular outflow tract (LVOT) and the aortic root is necessary for risk stratification and choice of appropriate treatment in patients with pathologies of the aortic valve and aortic root. Conventional 2D transthoracic echocardiographic (TTE) assessment is based on the assumption of a circular shaped LVOT and aortic root, although previous studies have indicated a more ellipsoid shape. 3D TTE and multidetector computed tomography (MDCT) applies planimetry and are not dependent on geometrical assumptions. The aim was to test accuracy, feasibility, and reproducibility of 3D TTE compared to 2D TTE assessment of LVOT and aortic root areas, with MDCT as reference.

METHODS AND RESULTS

We examined 51 patients with 2D/3D TTE and MDCT at the same day. All patients were re-examined with 2D/3D TTE on a different day to evaluate 2D and 3D re-test variability. Areas of LVOT, aortic annulus, and sinus were assessed using 2D, 3D TTE, and MDCT. Both 2D/3D TTE underestimated the areas compared to MDCT; however, 3D TTE areas were significantly closer to MDCT-areas. 2D vs. 3D mean MDCT-differences: LVOT 1.61 vs. 1.15 cm2, P = 0.019; aortic annulus 1.96 vs. 1.06 cm2, P < 0.001; aortic sinus 1.66 vs. 1.08 cm2, P = 0.015. Feasibility was 3D 76-79% and 2D 88-90%. LVOT and aortic annulus areas by 3D TTE had lowest variabilities; intraobserver coefficient of variation (CV) 9%, re-test variation CV 18-20%.

CONCLUSION

Estimation of LVOT and aortic root areas using 3D TTE is feasible, more precise and more accurate than 2D TTE.

Imaging diagnosis of aortic stenosis

Aortic valve stenosis (AS) is the commonest primary valve disorder with increasing prevalence with age. Trans-thoracic echocardiogram is the main imaging technique used to diagnose AS, but discrepancy in diagnosis has been described in almost one third of cases. Other imaging methods, particularly electrocardiogram (ECG)-gated computed tomography, have now emerged to further clarify the diagnosis of AS by both demonstrating the degree of calcification in the valve as well as aortic valve area. Cardiac magnetic resonance imaging allows accurate quantification of ventricular function and evaluation of the myocardium. This paper provides a comprehensive review of the diagnosis of AS for the radiologist.

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

BACKGROUND

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.

METHODS

We prospectively studied 134 patients (median age, 80 years; interquartile range, 73-87 years; 39% women) with AS, including 82 (61%) with severe AS and 52 (39%) with mild or moderate AS. LVOTA was traced using direct planimetry (LVOTA_biplane) and compared with LVOTA calculated using the circular assumption (LVOTA_circ). In a subset of patients who underwent cardiac computed tomography, direct planimetry of LVOTA was used as a reference standard.

RESULTS

LVOTA_biplane was significantly larger than LVOTA_circ (4.20 cm² [interquartile range, 3.66-4.90 cm²] vs 3.73 cm² [interquartile range, 3.14-4.15 cm²], P < .001). Among 30 patients who underwent cardiac computed tomography, LVOTA_biplane had better agreement with LVOTA by direct planimetry than LVOTA_circ (mean bias, -0.45 ± 0.63 vs -1.02 ± 0.63 cm²; P < .0001). Of 82 patients with severe AS (AVA ≤ 1 cm² using LVOTA_circ), 40 (49%) had discordant mean gradient (<40 mm Hg). By using LVOTA_biplane, 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.

CONCLUSIONS

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.

Feasibility and accuracy of real-time three-dimensional echocardiography in evaluating the aortic valve in children

Background

Aortic valve assessment by 2D transthoracic echocardiography is a relatively complex task owing to the unique anatomical features of the left ventricular outflow tract and its dynamic nature. We aimed to evaluate the accuracy of 3D transthoracic echocardiography [3D TTE] in assessing the aortic valve in children.

Results

The first group included 11 males and six females, with a mean age of 5.76 ± 6.39 years. All of these patients had aortic valve disease with a bicuspid variant. The second group included seven males and seven females, with a mean age of 4.4 ± 4.05 years. All of these patients had normal aortic valve morphology and had another congenital cardiac anomaly. The aortic valve annulus was assessed using the three modalities; 2D, 3D echocardiography in the vertical and horizontal diameters, and angiography. The aortic valve area was measured by 2D and 3D echocardiography using multiplane reformatted mode. The results of the analysis were then compared. They revealed that 3D echocardiographic measurement of the aortic annulus (horizontal diameter) correlated better with angiography than 2D and 3D (vertical diameter) echocardiographic measurements. There was a significant difference between the aortic valve area measured by 2D echocardiography and that measured by 3D echocardiography among the two groups, 2D echocardiography seems to underestimate the true aortic valve area.

Conclusion

The study concluded that 3D TTE with multiplane reformatted mode allows a more accurate assessment of the aortic valve when compared to 2D echocardiography and this correlates better with the angiographic findings.

Outcome of Normal-Flow Low-Gradient Severe Aortic Stenosis With Preserved Left Ventricular Ejection Fraction: A Propensity-Matched Study

Background

Normal‐flow, low‐gradient severe aortic stenosis (NF‐LG‐SAS), defined by aortic valve area <1 cm², mean gradient <40 mm Hg, and indexed stroke volume >35 mL/m², is the most prevalent form of low‐gradient aortic stenosis (AS). However, the true severity of AS and the management of NF‐LG‐SAS are controversial. The aim of this study was to evaluate the outcome of patients with NF‐LG‐SAS compared with moderate AS (MAS) and with high‐gradient severe‐AS (HG‐SAS).

Methods and Results

A total of 154 patients with NF‐LG‐SAS, 366 with MAS (aortic valve area between 1.0 and 1.3 cm²), and 1055 with HG‐SAS were included. On multivariate analysis, after adjustment for covariates of prognostic importance, NF‐LG‐SAS patients did not exhibit an excess risk of mortality compared with MAS patients under medical management (hazard ratio=1.13 [95% CI, 0.82‐1.56]; P=0.45) and under medical and surgical management (hazard ratio 1.06 [95% CI, 0.79‐1.43]; P=0.70), even after further adjustment for aortic valve replacement (hazard ratio=1.09 [95% CI, 0.81‐1.48]; P=0.56). The 6‐year cumulative incidence of aortic valve replacement (performed in accordance with guidelines) was comparable between the 2 groups (39±4% for NF‐LG‐SAS and 35±3% for MAS, P=0.10). After propensity score matching (n=226), NF‐LG‐SAS and MAS patients also had comparable outcomes under medical (P=0.41) and under medical and surgical management (P=0.52). NF‐LG‐SAS had better outcomes than HG‐SAS patients (adjusted hazard ratio 1.84 [95% CI, 1.18‐2.88]; P<0.001).

Conclusions

This study shows that patients with NF‐LG‐SAS have a comparable outcome to those with MAS when aortic valve replacement is performed during follow‐up according to guidelines, mostly at the stage of HG‐SAS. Rigorous echocardiographic assessment to rule out measurement errors and close follow‐up are essential to detect progression to true severe AS in NF‐LG‐SAS.

Comparison of Cardiac Output of Both 2-Dimensional and 3-Dimensional Transesophageal Echocardiography With Transpulmonary Thermodilution During Cardiac Surgery

OBJECTIVES

To compare agreement and variability of cardiac output measurement of 2-dimensional (2D) and 3D transesophageal echocardiography (TEE) with thermodilution before and after bypass.

DESIGN

Prospective observational study.

SETTING

Two tertiary hospitals.

INTERVENTIONS

Cardiac output (CO) was measured simultaneously with thermodilution and TEE by multiplying either the left ventricular outflow tract area (LVOTA) or aortic valve area (AVA), the velocity-time integral (VTI) of flow at the same site, and heart rate. The LVOTA was calculated using diameter for 2D TEE. Planimetry was used for 3D TEE. The AVA was measured using planimetry.

PARTICIPANTS

The study comprised 82 adult patients undergoing coronary or valve surgery.

MEASUREMENTS AND MAIN RESULTS

One hundred fifty-four complete sets of measurements were obtained (82 prebypass and 72 postbypass). All TEE methods had acceptable correlation and absence of proportional or fixed bias except for the left ventricular outflow tract (LVOT) VTI modal trace method, which had poor correlation and proportional but not fixed bias (regression coefficient [95% confidence interval], bias [percentage of mean CO]): 2D LVOT VTI modal trace 0.67 (0.54-0.80), -36.4%; 2D LVOT VTI outer edge trace 0.96 (0.80-1.12), -15.3%; 2D AVA planimetry 0.96 (0.75-1.18), +4.9%; 3D LVOT area planimetry 1.18 (0.96-1.41), +0.8%; 3D AVA planimetry 1.20 (0.93-1.46), +0.4%. All TEE methods had wide levels of agreement compared with thermodilution (-3.94 to +0.23 L/min, -2.83 to +1.28 L/min, -2.23 to +2.73 L/min, -2.35 to +2.42 L/min, and -2.57 to +2.61 L/min, respectively). Measurement variability was superior for all TEE methods compared with thermodilution before but not after bypass.

CONCLUSIONS

Although limits of agreement of CO measurement with 3D TEE and thermodilution are wide, 2D planimetry of the AVA and continuous wave Doppler may be substituted for thermodilution before and after bypass.

Inconsistency in aortic stenosis severity between CT and echocardiography: prevalence and insights into mechanistic differences using computational fluid dynamics

Objectives

The aims of this study were to evaluate the inconsistency of aortic stenosis (AS) severity between CT aortic valve area (CT-AVA) and echocardiographic Doppler parameters, and to investigate potential underlying mechanisms using computational fluid dynamics (CFD).

Methods

A total of 450 consecutive eligible patients undergoing transcatheter AV implantation assessment underwent CT cardiac angiography (CTCA) following echocardiography. CT-AVA derived by direct planimetry and echocardiographic parameters were used to assess severity. CFD simulation was performed in 46 CTCA cases to evaluate velocity profiles.

Results

A CT-AVA>1 cm² was present in 23% of patients with echocardiographic peak velocity≥4 m/s (r=−0.33) and in 15% patients with mean Doppler gradient≥40 mm Hg (r=−0.39). Patients with inconsistent severity grading between CT and echocardiography had higher stroke volume index (43 vs 38 mL/m², p<0.003) and left ventricular outflow tract (LVOT) flow rate (235 vs 192 cm³/s, p<0.001). CFD simulation revealed high flow, either in isolation (p=0.01), or when associated with a skewed velocity profile (p=0.007), as the main cause for inconsistency between CT and echocardiography.

Conclusion

Severe AS by Doppler criteria may be associated with a CT-AVA>1 cm² in up to a quarter of patients. CFD demonstrates that haemodynamic severity may be exaggerated on Doppler analysis due to high LVOT flow rates, with or without skewed velocity profiles, across the valve orifice. These factors should be considered before making a firm diagnosis of severe AS and evaluation with CT can be helpful.

Reliability of three-dimensional color flow Doppler and two-dimensional pulse wave Doppler transthoracic echocardiography for estimating cardiac output after cardiac surgery

BACKGROUND

Three-dimensional color flow Doppler (3DCF) is a new convenient technique for cardiac output (CO) measurement. However, to date, no one has evaluated the accuracy of 3DCF echocardiography for CO measurement after cardiac surgery. Therefore, this single-center, prospective study was designed to evaluate the reliability of three-dimensional color flow and two-dimensional pulse wave Doppler (2D-PWD) transthoracic echocardiography for estimating cardiac output after cardiac surgery.

METHODS

Post-cardiac surgical patients with a good acoustic window and a low dose or no dose of vasoactive drugs (norepinephrine < 0.05 μg/kg/min) were enrolled for CO estimation. Three different methods (third generation FloTrac/Vigileo™ [FT/V] system as the reference method, 3DCF, and 2D-PWD) were used to estimate CO before and after interventions (baseline, after volume expansion, and after a dobutamine test).

RESULTS

A total of 20 patients were enrolled in this study, and 59 pairs of CO measurements were collected (one pair was not included because of increasing drainage after the dobutamine test). Pearson's coefficients were 0.260 between the CO-FT/V and CO-PWD measurements and 0.729 between the CO-FT/V and CO-3DCF measurements. Bland-Altman analysis showed the bias between the absolute values of CO-FT/V and CO-PWD measurements was - 0.6 L/min with limits of agreement between - 3.3 L/min and 2.2 L/min, with a percentage error (PE) of 61.3%. The bias between CO-FT/V and CO-3DCF was - 0.14 L/min with limits of agreement between - 1.42 L /min and 1.14 L/min, with a PE of 29.9%. Four-quadrant plot analysis showed the concordance rate between ΔCO-PWD and ΔCO-3FT/V was 93.3%.

CONCLUSIONS

In a comparison with the FT/V system, 3DCF transthoracic echocardiography could accurately estimate CO in post-cardiac surgical patients, and the two methods could be considered interchangeable. Although 2D-PWD echocardiography was not as accurate as the 3D technique, its ability to track directional changes was reliable.

Assessment of aortic valve tract dynamics using automatic tracking of 3D transesophageal echocardiographic images

The assessment of aortic valve (AV) morphology is paramount for planning transcatheter AV implantation (TAVI). Nowadays, pre-TAVI sizing is routinely performed at one cardiac phase only, usually at mid-systole. Nonetheless, the AV is a dynamic structure that undergoes changes in size and shape throughout the cardiac cycle, which may be relevant for prosthesis selection. Thus, the aim of this study was to present and evaluate a novel software tool enabling the automatic sizing of the AV dynamically in three-dimensional (3D) transesophageal echocardiography (TEE) images. Forty-two patients who underwent preoperative 3D-TEE images were retrospectively analyzed using the software. Dynamic measurements were automatically extracted at four levels, including the aortic annulus. These measures were used to assess the software's ability to accurately and reproducibly quantify the conformational changes of the aortic root and were validated against automated sizing measurements independently extracted at distinct time points. The software extracted physiological dynamic measurements in less than 2 min, that were shown to be accurate (error 2.2 ± 26.3 mm² and 0.0 ± 2.53 mm for annular area and perimeter, respectively) and highly reproducible (0.85 ± 6.18 and 0.65 ± 7.90 mm² of intra- and interobserver variability, respectively, in annular area). Using the maximum or minimum measured values rather than mid-systolic ones for device sizing resulted in a potential change of recommended size in 7% and 60% of the cases, respectively. The presented software tool allows a fast, automatic and reproducible dynamic assessment of the AV morphology from 3D-TEE images, with the extracted measures influencing the device selection depending on the cardiac moment used to perform its sizing. This novel tool may thus ease and potentially increase the observer's confidence during prosthesis' size selection at the preoperative TAVI planning.

Validation of "left ventricular early inflow-outflow index": A novel echocardiographic method for quantification of mitral regurgitation in an Indian population with special focus on rheumatic etiology

BACKGROUND

Quantification of mitral regurgitation (MR) has always required an "integrated approach" as there is no single gold-standard method. We investigated a new Doppler-derived parameter "left ventricular early inflow-outflow index (LVEIO)" for the quantification of MR and its likelihood to predict severe MR in correlation with already established parameters in an Indian population including a large subset of patients with rheumatic etiology.

METHODS

A prospective study was performed at a major tertiary care center in western India over a 5-month period. Five hundred patients diagnosed with isolated MR including 260 (52%) patients with rheumatic etiology were included in the study after applying exclusion criteria. We analyzed MR using color flow jet, effective regurgitant orifice area (EROA), and vena contracta (VC) width. LVEIO is a simplification of the regurgitant volume (RV) method, which was calculated as "E velocity divided by LV outflow velocity integrated over the systolic ejection period left ventricular outflow tract velocity time integral" and compared with the established parameters.

RESULTS

LVEIO was 4.65 ± 1.45, 6.56 ± 1.52, and 9.91 ± 3.70 among patients diagnosed with mild, moderate, and severe MR, respectively (p < 0.001). Those with LVEIO ≥8 were the most likely to have severe MR (positive likelihood ratio: 10.42). LVEIO had specificity of 93.25% for diagnosis of severe MR with positive predictive value of 86.36%. There was positive correlation observed between LVEIO and VC width (r = 0.591), RV (r = 0.410), and EROA (r = 0.778) (all p < 0.001) in the Pearson correlation test. The specificity of LVEIO remained consistent in diagnosing severe MR in patients with rheumatic etiology.

CONCLUSION

LVEIO is a simple yet specific Doppler echocardiographic parameter for estimation of severity of MR including that of rheumatic etiology.

Evaluation of inert gas rebreathing for determination of cardiac output: influence of age, gender and body size

The aim of this study was to evaluate an inert gas rebreathing method (Innocor) for measurement of cardiac output and related haemodynamic variables and to provide robust normative data describing the influence of age, gender and body size on these variables. Four separate studies were conducted: measurement repeatability (study 1, n = 45); postural change (study 2, n = 40); response to submaximal cycling exercise (study 3, n = 20); and the influence of age, gender and body size (study 4, n = 1400). Repeated measurements of cardiac output, stroke volume and heart rate were similar, with low mean (±SD) differences (0.26 ± 0.53 L/min, 0 ± 11 mL and 2 ± 6beats/min, respectively). In addition, cardiac output and stroke volume both declined progressively from supine to seated and standing positions (P < 0.001 for both) and there was a stepwise increase in both parameters moving from rest to submaximal exercise (P < 0.001 for both). In study 4, there was a significant age-related decline in cardiac output and stroke volume in males and females, which remained significant after adjusting for body surface area (BSA, P < 0.001 for all comparisons). Both parameters were also significantly higher in those with high body mass index (BMI; P < 0.01 versus those with normal BMI for all comparisons), although indexing cardiac output and stroke volume to BSA reversed these trends. Inert gas rebreathing using the Innocor device provides repeatable measurements of cardiac output and related indices, which are sensitive to the effects of acute physiological manoeuvres. Moreover, inert gas rebreathing is a suitable technique for examining chronic influences such as age, gender and body size on key haemodynamic components of the arterial blood pressure.

Anatomic estimation of aortic stenosis severity vs "fusion" of data from computed tomography and Doppler echocardiography

AIM

Two-dimensional, transthoracic echocardiography does not account for the noncircular anatomy of the left ventricular outflow tract (LVOT) and may therefore underestimate LVOT area. Fusion of computed tomography (CT)-derived LVOT area and Doppler-derived flow data has been proposed to improve assessment of aortic valve area (AVA) and classification of aortic stenosis severity. For hemodynamic reasons, effective AVA has to be smaller than anatomic AVA. The aim of the study was to test the "fusion approach" by comparing effective CT-derived AVA with anatomic AVA from CT planimetry.

METHODS AND RESULTS

Data of 244 consecutive patients (mean age 81 ± 5 years, 61% female) with aortic stenosis were retrospectively analyzed comparing effective AVA (calculated from the continuity equation using CT-LVOT and transthoracic Doppler measurements) with anatomic AVA based on CT planimetry. Substituting the LVOT area from transthoracic echocardiography (TTE) by the CT-LVOT resulted in an increase in AVA from 0.74 ± 0.15 to 0.92 ± 0.18cm² (P < .01), which was larger than anatomic AVA (0.82 ± 0.15cm²). Similar results were obtained based on planimetry from transesophageal echocardiography (TEE; AVA 0.79 ± 0.14cm², P < .01 vs CT-LVOT) and in the subgroup presenting with low-gradient severe aortic stenosis and preserved ejection fraction (n = 67, AVA from TTE 0.76 ± 0.09; from CT-LVOT 0.97 ± 0.14; CT planimetry 0.86 ± 0.12; TEE planimetry 0.82 ± 0.13cm²).

CONCLUSION

Fusion of CT-derived LVOT area with Doppler echocardiography results in a calculated effective AVA that is larger than the corresponding anatomic AVA. Therefore, adjustment of partition values may be warranted when using this approach.

[Consensus on Perioperative Transesophageal Echocardiography of the Brazilian Society of Anesthesiology and the Department of Cardiovascular Image of the Brazilian Society of Cardiology]

Through the Life Cycle of Intraoperative Transesophageal Echocardiography (ETTI/SBA) the Brazilian Society of Anesthesiology, together with the Department of Cardiovascular Image of the Brazilian Society of Cardiology (DIC/SBC), createded a task force to standardize the use of intraoperative transesophageal echocardiography by Brazilian anesthesiologists and echocardiographers based on scientific evidence from the Society of Cardiovascular Anesthesiologists/American Society of Echocardiography (SCA/ASE) and the Brazilian Society of Cardiology.

Consensus on Perioperative Transesophageal Echocardiography of the Brazilian Society of Anesthesiology and the Department of Cardiovascular Image of the Brazilian Society of Cardiology

Through the Life Cycle of Intraoperative Transesophageal Echocardiography (ETTI/SBA) the Brazilian Society of Anesthesiology, together with the Department of Cardiovascular Image of the Brazilian Society of Cardiology (DIC/SBC), created a task force to standardize the use of intraoperative transesophageal echocardiography by Brazilian anesthesiologists and echocardiographers based on scientific evidence from the Society of Cardiovascular Anesthesiologists/American Society of Echocardiography (SCA/ASE) and the Brazilian Society of Cardiology.

Influence of the Quantity of Aortic Valve Calcium on the Agreement Between Automated 3-Dimensional Transesophageal Echocardiography and Multidetector Row Computed Tomography for Aortic Annulus Sizing

Accurate aortic annulus sizing is key for selection of appropriate transcatheter aortic valve implantation (TAVI) prosthesis size. The present study compared novel automated 3-dimensional (3D) transesophageal echocardiography (TEE) software and multidetector row computed tomography (MDCT) for aortic annulus sizing and investigated the influence of the quantity of aortic valve calcium (AVC) on the selection of TAVI prosthesis size. A total of 83 patients with severe aortic stenosis undergoing TAVI were evaluated. Maximal and minimal aortic annulus diameter, perimeter, and area were measured. AVC was assessed with computed tomography. The low and high AVC burden groups were defined according to the median AVC score. Overall, 3D TEE measurements slightly underestimated the aortic annulus dimensions as compared with MDCT (mean differences between maximum, minimum diameter, perimeter, and area: -1.7 mm, 0.5 mm, -2.7 mm, and -13 mm², respectively). The agreement between 3D TEE and MDCT on aortic annulus dimensions was superior among patients with low AVC burden (<3,025 arbitrary units) compared with patients with high AVC burden (≥3,025 arbitrary units). The interobserver variability was excellent for both methods. 3D TEE and MDCT led to the same prosthesis size selection in 88%, 95%, and 81% of patients in the total population, the low, and the high AVC burden group, respectively. In conclusion, the novel automated 3D TEE imaging software allows accurate and highly reproducible measurements of the aortic annulus dimensions and shows excellent agreement with MDCT to determine the TAVI prosthesis size, particularly in patients with low AVC burden.

3D and 4D Ultrasound: Current Progress and Future Perspectives

PURPOSE OF REVIEW

Three-dimensional (3D) echocardiography (3DE) and 4-dimensional echocardiography (4DE), also known as real-time (RT) 3DE (RT3DE), are rapidly emerging technologies which have made significant impact in the clinical arena over the years. This review will discuss the recent applications of 3DE in diagnosing and treating different types of cardiovascular disease.

RECENT FINDINGS

Recent studies using 3DE expanded on prior findings and introduced additional applications to different cardiac conditions. Some studies have used 3D parameters to prognosticate long-term outcomes. Numerous innovative software designs including fully automated algorithms have been introduced to better evaluate valvular heart disease and cardiac function.

SUMMARY

With further evolution of 3DE technologies, this imaging modality will emerge as a powerful tool and likely become the imaging modality of choice in the diagnosis and management of various cardiac disorders.

Left ventricular outflow tract obstruction-be prepared!

The current trend to treat hypotension in critically ill patients is to place a greater emphasis on inotropic support and less on fluid resuscitation in order to limit the potential harm from fluid overload. This combination may trigger left ventricular outflow tract obstruction (LVOTO) in susceptible patients. Although LVOTO is classically described in patients with hypertrophic cardiomyopathy it has been reported in other conditions including septic shock, apical ballooning syndrome, myocardial infarction, respiratory failure, and post valvular surgery. It is more common in the elderly, females, and in patients with hypertension, diabetes, and chronic vascular disease because of predisposing anatomical conditions such as left ventricular hypertrophy, small left ventricle size, sigmoid septum and alterations in the positions of the aortic and mitral valve annular planes. The onset of LVOTO is largely unpredictable due to a complex interplay between preload, afterload, heart rhythm and rate in susceptible patients. The consequences of missing this treatable condition may lead to life-threatening hypotension refractory to, or exacerbated by, a further increase in inotropic support. Dynamic LVOTO should be considered in any hypotensive intensive care patient. Echocardiography is perhaps the best tool to assess LVOTO and its underlying pathophysiology in the critically ill. Detection of LVOTO is a relatively simple task using a combination of two-dimensional, M-mode and spectral Doppler imaging by an operator alert to the possible diagnosis.

Three-Dimensional Measurement of Aortic Annulus Dimensions Using Area or Circumference for Transcatheter Aortic Valve Replacement Valve Sizing: Does It Make a Difference?

BACKGROUND

The use of transcatheter aortic valve replacement (TAVR) is increasing worldwide. We present our 6-year experience using three-dimensional (3D) transesophageal echocardiography (TEE) and investigate whether different sizing methods of the aortic annulus lead to different prosthesis size that may impact outcome.

METHODS

We investigated 262 patients who underwent TAVR and had 3D TEE data sets of the aortic annulus. We have used the area-derived diameter (D_area = 2(area/π)) and the circumference-derived diameter (D_circ = Circumference/π) to size the prosthesis in separate populations in different time periods.

RESULTS

The D_circ method is correlated with lower incidence of paravalvular aortic regurgitation (PVAR; odds ratio = 0.44, 95% confidence interval, 0.23-0.85; P = .015). Other factors associated with PVAR were the cover index, area-mismatch index, and circumference-mismatch index. Retrospectively, for the purposes of the study, we used the Edwards-Sapien 3 Valve 3D sizing guide in all patients, to predict the hypothetical valve size with each method. In the whole population, the calculated D_circ was higher in all cases (D_circ = 23.4 ± 2.3 mm vs D_area = 22.9 ± 2.3 mm; P < .001). The two methods had good agreement in predicting the valve size (kappa = 0.600). In total, 192 (73.3%) patients were assigned for the same prosthesis size, whereas 70 (26.7%) would be eligible for a different size, of which 44 (16.7%) would definitely have had a different valve implanted.

CONCLUSION

Using the aortic annulus area or circumference to calculate the annular diameter provides different values. Comparing the two methods, a different prosthesis size could have been implanted in 26.7% of patients. In our series the use of circumference-derived diameter resulted in lower incidence of PVAR. The findings of this study may be independent of the imaging modality and may therefore also apply to computed tomography-based aortic annulus measurements, but this needs to be further investigated.

Validation of Noninvasive Measurement of Cardiac Output Using Inert Gas Rebreathing in a Cohort of Patients With Heart Failure and Reduced Ejection Fraction

BACKGROUND

Cardiac output (CO) is a key indicator of cardiac function in patients with heart failure. No completely accurate method is available for measuring CO in all patients. The objective of this study was to validate CO measurement using the inert gas rebreathing (IGR) method against other noninvasive and invasive methods of CO quantification in a cohort of patients with heart failure and reduced ejection fraction.

METHODS AND RESULTS

The study included 97 patients with heart failure and reduced ejection fraction (age 42±15.5 years; 64 patients (65.9%) had idiopathic dilated cardiomyopathy and 21 patients (21.6%) had ischemic heart disease). Median left ventricle ejection fraction was 24% (10%-36%). Patients with atrial fibrillation were excluded. CO was measured using 4 methods (IGR, cardiac magnetic resonance imaging, cardiac catheterization, and echocardiography) and indexed to body surface area (cardiac index [CI]). All studies were performed within 48 hours. Median CI measured by IGR was 1.75, by cardiac magnetic resonance imaging was 1.82, by cardiac catheterization was 1.65, and by echo was 1.7 L·min^-1·m^-2. There were significant modest linear correlations between IGR-derived CI and cardiac magnetic resonance imaging-derived CI (r=0.7; P<0.001), as well as cardiac catheterization-derived CI (r=0.6; P<0.001). Using Bland-Altman analysis, the agreement between the IGR method and the other methods was as good as the agreement between any 2 other methods with each other.

CONCLUSIONS

The IGR method is a simple, accurate, and reproducible noninvasive method for quantification of CO in patients with advanced heart failure. The prognostic value of this simple measurement needs to be studied prospectively.

Modified continuity equation using left ventricular outflow tract three-dimensional imaging for aortic valve area estimation

PURPOSE

Aortic valve area (AVA) is usually estimated by the continuity equation (CE) in which the left ventricular outflow tract (LVOT) area is calculated assuming a circular shape. This study aimed to compare measurements of LVOT area using standard 2D transthoracic echocardiography (2DTTE), 3D transesophageal echocardiography (3DTEE), and multidetector computed tomography (MDCT) and assess their relative impact on AVA estimated by the CE.

METHODS AND RESULTS

We prospectively enrolled 60 patients with severe aortic stenosis (AS) referred for transcatheter aortic valve replacement (TAVR) who systematically underwent 2DTTE, 3DTEE, and MDCT. Mean LVOT areas obtained by 2DTTE (3.28±0.66 cm² ) and 3DTEE (3.95±0.90 cm² ) were significantly underestimated when compared to the mean MDCT LVOT area (4.31±0.99 cm² ). LVOT was rather elliptical than round, with a mean eccentricity index of 1.47 (ratio of maximum to minimum LVOT diameters) assessed by MDCT. Mean TTE AVA estimated by the CE was 0.62±0.20 cm² . Substitution of 2DTTE LVOT area by 3DTEE LVOT area in the CE resulted in AVA of 0.74±0.24 cm² , while using MDCT LVOT area held an AVA of 0.80±0.24 cm² . MDCT-derived AVA was similar to MDCT planimetric AVA and allowed 24% of patients to be reclassified from severe to moderate AS.

CONCLUSIONS

2DTTE and 3DTEE underestimate LVOT area when compared to MDCT with significant impact on AVA estimation. Assessment through MDCT fusion AVA may be of incremental value in patients with discrepant severity criteria for AS.

Impact of left ventricular outflow tract ellipticity on the grading of aortic stenosis in patients with normal ejection fraction

BACKGROUND

The pathophysiology of paradoxical low-gradient (LG) severe aortic stenosis (SAS) remains controversial. As low transvalvular flow has been implicated, we sought to investigate the impact of left ventricular outflow tract (LVOT) ellipticity on the estimation of the LV stroke volume, the calculation of the aortic valve area (AVA) by use of the continuity equation and on AS severity grading.

METHODS

We studied 190 consecutive patients (mean age: 72 ± 13 years; male: 57%) with SAS (indexed AVA < 0.6 cm2/m2) and preserved LV ejection fraction, including 120 patients with severe high gradient (HG) AS and 70 with severe paradoxical LG-AS. AS severity, LV volumes and LVOT ellipticity were assessed by 2D-Doppler echocardiography and cardiac magnetic resonance (CMR).

RESULTS

The LVOT exhibited an elliptical shape on CMR images, with a shorter anterior-posterior than median-lateral diameter (2.2 ± 0.2 vs 2.8 ± 0.3 cm, p < 0.01). Accordingly, the LVOT area measured by planimetry was larger than by 2D-echocardiography, assuming a circular orifice (4.9 ± 0.9 cm2 vs 3.7 ± 0.8 cm2, p < 0.01). Inputting the elliptical LVOT area into the continuity equation resulted in a 29% increase in the indexed AVA (from 0.41 ± 0.09 cm2 to 0.54 ± 0.10 cm2). Accordingly, 30 (43%) patients with severe paradoxical LG-SAS were reclassified as having moderate AS. Similar results were obtained when considering 3D-echo for direct planimetry of the LVOT in a subset of 75 patients.

CONCLUSIONS

Our results confirm that the LVOT is elliptical in shape and that taking this parameter into account in the calculation of the AVA results in reclassification of 43% of patients with severe paradoxical LG-AS into moderate AS.

Calcification Characteristics of Low-Flow Low-Gradient Severe Aortic Stenosis in Patients Undergoing Transcatheter Aortic Valve Replacement

Low-flow low-gradient severe aortic stenosis (LFLGAS) is associated with worse outcomes. Aortic valve calcification patterns of LFLGAS as compared to non-LFLGAS have not yet been thoroughly assessed. 137 patients undergoing transcatheter aortic valve replacement (TAVR) with preprocedural multidetector computed tomography (MDCT) and postprocedural transthoracic echocardiography were enrolled. Calcification characteristics were assessed by MDCT both for the total aortic valve and separately for each leaflet. 34 patients had LFLGAS and 103 non-LFLGAS. Total aortic valve calcification volume (p < 0.001), mass (p < 0.001), and density (p = 0.004) were lower in LFLGAS as compared to non-LFLGAS patients. At 30-day follow-up, mean transaortic pressure gradients and more than mild paravalvular regurgitation did not differ between groups. In conclusion, LFLGAS and non-LFLGAS express different calcification patterns which, however, did not impact on device success after TAVR.

Recent advances in echocardiography for valvular heart disease

Echocardiography is the imaging modality of choice for the assessment of patients with valvular heart disease. Echocardiographic advancements may have particular impact on the assessment and management of patients with valvular heart disease. This review will summarize the current literature on advancements, such as three-dimensional echocardiography, strain imaging, intracardiac echocardiography, and fusion imaging, in this patient population.

Left ventricular early inflow-outflow index: a novel echocardiographic indicator of mitral regurgitation severity

BACKGROUND

No gold standard currently exists for quantification of mitral regurgitation (MR) severity. Classification by echocardiography is based on integrative criteria using color and spectral Doppler and anatomic measurements. We hypothesized that a simple Doppler left ventricular early inflow-outflow index (LVEIO), based on flow velocity into the left ventricle (LV) in diastole and ejected from the LV in systole, would add incrementally to current diagnostic criteria. LVEIO was calculated by dividing the mitral E-wave velocity by the LV outflow velocity time integral.

METHODS AND RESULTS

Transthoracic echocardiography reports from Montefiore Medical Center and its referring clinics from July 1, 2011, to December 31, 2011 (n=11 235) were reviewed. The MR severity reported by a cardiologist certified by the National Board of Echocardiography was used as a reference standard. Studies reporting moderate or severe MR (n=550) were reanalyzed to measure effective regurgitant orifice area by the proximal isovelocity surface area method, vena contracta width, MR jet area, and left-sided chamber volumes. LVEIO was 9.3±3.9, 7.0±3.2, and 4.2±1.7 among those with severe, moderate, and insignificant MR, respectively (ANOVA P<0.001). By receiver operating characteristic analysis, area under the curve for LVEIO was 0.92 for severe MR. Those with LVEIO ≥8 were likely to have severe MR (likelihood ratio 26.5), whereas those with LVEIO ≤4 were unlikely to have severe MR (likelihood ratio 0.11). LVEIO performed better in those with normal LV ejection fraction (≥50%) compared with those with reduced LV ejection fraction (<50%) (area under the curve 0.92 versus 0.80, P<0.001). By multivariate logistic regression analysis, LVEIO was independently associated with severe MR when compared with vena contracta width, MR jet area, and effective regurgitant orifice area measured by the proximal isovelocity surface area method.

CONCLUSION

LVEIO is a simple-to-use echocardiographic parameter that accurately identifies severe MR, particularly in patients with normal LV ejection fraction.