Measurement Of Right Ventricular Ejection Fraction Research Articles

Ferumoxytol-Enhanced Cardiac Cine MRI Reconstruction Using a Variable-Splitting Spatiotemporal Network.

Balanced steady-state free precession (bSSFP) imaging is commonly used in cardiac cine MRI but prone to image artifacts. Ferumoxytol-enhanced (FE) gradient echo (GRE) has been proposed as an alternative. Utilizing the abundance of bSSFP images to develop a computationally efficient network that is applicable to FE GRE cine would benefit future network development. To develop a variable-splitting spatiotemporal network (VSNet) for image reconstruction, trained on bSSFP cine images and applicable to FE GRE cine images. Retrospective and prospective. 41 patients (26 female, 53 ± 19 y/o) for network training, 31 patients (19 female, 49 ± 17 y/o) and 5 healthy subjects (5 female, 30 ± 7 y/o) for testing. 1.5T and 3T, bSSFP and GRE. VSNet was compared to VSNet with total variation loss, compressed sensing and low rank methods for 14× accelerated data. The GRAPPA×2/×3 images served as the reference. Peak signal-to-noise-ratio (PSNR), structural similarity index (SSIM), left ventricular (LV) and right ventricular (RV) end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were measured. Qualitative image ranking and scoring were independently performed by three readers. Latent scores were calculated based on scores of each method relative to the reference. Linear mixed-effects regression, Tukey method, Fleiss' Kappa, Bland-Altman analysis, and Bayesian categorical cumulative probit model. A P-value <0.05 was considered statistically significant. VSNet achieved significantly higher PSNR (32.7 ± 0.2), SSIM (0.880 ± 0.004), rank (2.14 ± 0.06), and latent scores (-1.72 ± 0.22) compared to other methods (rank >2.90, latent score < -2.63). Fleiss' Kappa was 0.52 for scoring and 0.61 for ranking. VSNet showed no significantly different LV and RV ESV (P = 0.938) and EF (P = 0.143) measurements, but statistically significant different (2.62 mL) EDV measurements compared to the reference. VSNet produced the highest image quality and the most accurate functional measurements for FE GRE cine images among the tested 14× accelerated reconstruction methods. 3 TECHNICAL EFFICACY: Stage 1.

Pressure-based estimation of right ventricular ejection fraction.

AimsA method for estimating right ventricular ejection fraction (RVEF) from RV pressure waveforms was recently validated in an experimental model. Currently, cardiac magnetic resonance imaging (MRI) is the clinical reference standard for measurement of RVEF in pulmonary arterial hypertension (PAH). The present study was designed to test the hypothesis that the pressure‐based method can detect clinically significant reductions in RVEF as determined by cardiac MRI in patients with PAH.Methods and resultsRVEF estimates derived from analysis of RV pressure waveforms recorded during right heart catheterization (RHC) in 25 patients were compared with cardiac MRI measurements of RVEF obtained within 24 h. Three investigators blinded to cardiac MRI results independently performed pressure‐based RVEF estimation with the mean of their results used for comparison. Linear regression was used to assess correlation, and a receiver operator characteristic (ROC) curve was derived to define ability of the pressure‐based method to detect a maladaptive RV response, defined as RVEF <35% on cardiac MRI. In 23 patients, an automated adaptation of the pressure‐based RVEF method was also applied as proof of concept for beat‐to‐beat RVEF monitoring. The study cohort was comprised of 16 female and 9 male PAH patients with an average age of 53 ± 13 years. RVEF measured by cardiac MRI ranged from 16% to 57% (mean 37.7 ± 11.6%), and estimated RVEF from 15% to 54% (mean 36.2 ± 11.2%; P = 0.6). Measured and estimated RVEF were significantly correlated (r 2 = 0.78; P < 0.0001). ROC curve analysis demonstrated an area under the curve of 0.94 ± 0.04 with a sensitivity of 81% and specificity of 85% for predicting a maladaptive RV response. As a secondary outcome, with the recognized limitation of non‐coincident measures, Bland–Altman analysis was performed and indicated minimal bias for estimated RVEF (−1.5%) with limits of agreement of ± 10.9%. Adaptation of the pressure‐based estimation method to provide beat‐to‐beat RVEF also demonstrated significant correlation between the median beat‐to‐beat value over 10 s with cardiac MRI (r 2 = 0.66; P < 0.001), and an area under the ROC curve of 0.94 ± 0.04 (CI = 0.86 to 1.00) with sensitivity and specificity of 78% and 86%, respectively, for predicting a maladaptive RV response.ConclusionsPressure‐based estimation of RVEF correlates with cardiac MRI and detects clinically significant reductions in RVEF. Study results support potential utility of pressure‐based RVEF estimation for assessing the response to diagnostic or therapeutic interventions during RHC.

Assessment of right ventricular size and function from cardiovascular magnetic resonance images using artificial intelligence

BackgroundTheoretically, artificial intelligence can provide an accurate automatic solution to measure right ventricular (RV) ejection fraction (RVEF) from cardiovascular magnetic resonance (CMR) images, despite the complex RV geometry. However, in our recent study, commercially available deep learning (DL) algorithms for RVEF quantification performed poorly in some patients. The current study was designed to test the hypothesis that quantification of RV function could be improved in these patients by using more diverse CMR datasets in addition to domain-specific quantitative performance evaluation metrics during the cross-validation phase of DL algorithm development.MethodsWe identified 100 patients from our prior study who had the largest differences between manually measured and automated RVEF values. Automated RVEF measurements were performed using the original version of the algorithm (DL1), an updated version (DL2) developed from a dataset that included a wider range of RV pathology and validated using multiple domain-specific quantitative performance evaluation metrics, and conventional methodology performed by a core laboratory (CORE). Each of the DL-RVEF approaches was compared against CORE-RVEF reference values using linear regression and Bland–Altman analyses. Additionally, RVEF values were classified into 3 categories: ≤ 35%, 35–50%, and ≥ 50%. Agreement between RVEF classifications made by the DL approaches and the CORE measurements was tested.ResultsCORE-RVEF and DL-RVEFs were obtained in all patients (feasibility of 100%). DL2-RVEF correlated with CORE-RVEF better than DL1-RVEF (r = 0.87 vs. r = 0.42), with narrower limits of agreement. As a result, DL2 algorithm also showed increasing accuracy from 0.53 to 0.80 for categorizing RV function.ConclusionsThe use of a new DL algorithm cross-validated on a dataset with a wide range of RV pathology using multiple domain-specific metrics resulted in a considerable improvement in the accuracy of automated RVEF measurements. This improvement was demonstrated in patients whose images were the most challenging and resulted in the largest RVEF errors. These findings underscore the critical importance of this strategy in the development of DL approaches for automated CMR measurements.

High Variability of Right Ventricular Volumes and Function in Adults with Severe Pulmonary Regurgitation Late After Tetralogy of Fallot Repair

Our aim was to assess changes of right ventricular end-diastolic volumes (RVEDVi) and right ventricular ejection fraction (RVEF) in asymptomatic adults with repaired tetralogy of Fallot, with native right ventricular outflow tract and severe pulmonary regurgitation by serial cardiac magnetic resonance imaging (CMR). The study included 23 asymptomatic adults who underwent ≥3 CMR studies (total of 88 CMR studies). We compared changes in RVEDVi and RVEF between first and last study (median follow-up: 8.8years, interquartile range: 6.3 to 13.1 years) and between all study pairs. Variability of measurements between study pairs (65 consecutive and 139 nonconsecutive CMR study pairs) were assessed using Bland-Altman analysis and intraclass correlation coefficients. On average, there were no significant changes of RVEDVi or RVEF over the study period (change in RVEDVi: +0.4 ± 17.8ml/m2, change in RVEF: -1.0 ± 5.5%). Assessment of variability of measurements between study pairs demonstrated no systematic change in RVEDVi and RVEF between study pairs with limits of agreement within the range of previously published studies (RVEDVi -29.1 to +27.2ml/m2; RVEF -11.5% to 10.2%). High intraclass correlation coefficients for RVEDVi (0.943, 95% CI 0.906 to 0.965, p <0.001) and RVEF (0.815, 95% CI 0.697 to 0.887, p <0.0001) indicate high reliability of reported measurements. In conclusion, in asymptomatic adults with repaired tetralogy of Fallot with native right ventricular outflow tracts and severe pulmonary regurgitation, CMR measurements of RV volumes and RVEF remain stable during follow-up with variability between CMR studies in individual patients, as expected for interobserver and interstudy variability. Measurements derived from a single CMR study or changes occurring between 2 CMR studies should be used with caution for clinical decision-making.

Comprehensive Assessment of Right Ventricular Function by Three-Dimensional Speckle-Tracking Echocardiography: Comparisons with Cardiac Magnetic Resonance Imaging

Three-dimensional speckle-tracking echocardiography (3D-STE) has been increasingly used to quantify right ventricular (RV) function. However, direct comparisons of 3D-STE with cardiac magnetic resonance (CMR) imaging for evaluation of RV function are limited. This study aimed to test the feasibility and accuracy of 3D-STE for the quantification of RV volumes, ejection fraction (EF), and longitudinal strain in comparison with CMR imaging and to determine whether 3D-STE for RV strain is superior to two-dimensional (2D) STE in comparison with CMR imaging. A total of 195 consecutive patients referred for both CMR imaging and echocardiography were studied. Right ventricular end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RVEF, and 3D RV longitudinal strain (3D-RVLS) of the free wall by 3D-STE and 2D-RVLS of the free wall by 2D-STE, were compared with CMR measurements. Pearson correlation and Bland-Altman analyses were used to assess the intertechnique agreement. Right ventricular 3D-STE was feasible in 174 patients (89%). Right ventricular volumes and EF determined by 3D-STE strongly correlated with CMR values (RVEDV, r=0.94; RVESV, r=0.96; RVEF, r=0.91; all P<.001). Three-dimensional STE slightly underestimated the RV volumes and longitudinal strain and overestimated the RVEF. The 3D-RVLS values correlated better than 2D-RVLS values with CMR values (0.85 vs 0.64, P<.001) with smaller bias and narrower limits of agreement (bias: 2.0 and 2.6; limits of agreement: 8.5 and 12.5, respectively). The bias and limits of agreement for 3D-STE-obtained RVLS were increased in patients with RV dilation, RVEF < 45%, or lower frame rate compared with those with normal RV size, RVEF ≥ 45%, or higher frame rate, respectively. Right ventricular 3D-STE measurements were highly reproducible. The 3D-STE measurements of RV volumes, EF, and longitudinal strain are highly feasible and reproducible, and data measured by 3D-STE correlate strongly with those determined using CMR imaging. Thus, 3D-STE may be a valid alternative to CMR imaging for the quantification of RV function in everyday clinical practice.

Abstract 16189: Cardiovascular Risk Prediction Using Fully Automated Artificial Intelligence Algorithms for the Assessment of Right Ventricular Function From Cardiac Magnetic Resonance Images

Background: It is unclear whether artificial intelligence (AI) can provide automatic solutions to measure right ventricular ejection fraction (RVEF), due to the complex RV geometry. Although several deep learning (DL) algorithms are available to quantify RVEF from cardiac magnetic resonance (CMR) images, there has been no systematic comparison of these algorithms, and the prognostic value of these automated measurements is unknown. We aimed to determine whether RVEF measurements made using DL algorithms could be used to risk stratify patients similarly to measurements made by an expert. Methods: We identified from a pre-existing registry 200 patients who underwent CMR. RVEF was determined using 3 fully automated commercial DL algorithms (DL-RVEF) and also by a clinical expert (CLIN-RVEF) using conventional methodology. Each of the DL-RVEF approaches was compared against CLIN-RVEF using linear regression and Bland-Altman analyses. In addition, RVEF values were classified according to clinically important cutoffs: &lt;35%, 35-50%, ≥50%, and rates of disagreement with the reference classification were determined. ROC analysis was performed to evaluate the ability of CLIN-RVEF and each of the DL-RVEF based classifications to predict major adverse cardiovascular events (MACE). Results: The CLIN-RVEF and the three DL-RVEFs were obtained in all patients. We found only modest correlations between DL-RVEF and CLIN-RVEF (figure). The DL-RVEF algorithms had accuracy ranging from 0.59 to 0.78 for categorizing RV function. Nevertheless, ROC analysis showed no significant differences between the 4 approaches in predicting MACE, as reflected by respective AUC values of 0.68, 0.69, 0.64 and 0.63. Conclusions: Although the automated algorithms predicted patient outcomes as well as the CLIN-RVEF, the agreement between DL-RVEF and the clinical expert’s measurements was not optimal. DL approaches need further refinements to improve automated assessment of RV function.

Prognostic Value of the Right Ventricular Ejection Fraction, Assessed by Fully Automated Three-Dimensional Echocardiography: A Direct Comparison of Analyses Using Right Ventricular–Focused Views versus Apical Four-Chamber Views

Right ventricular (RV) three-dimensional echocardiographic (3DE) data sets are acquired from either the RV-focused view (RVFV) or the apical four-chamber view (4CV). The prognostic value of 3DE RV ejection fraction (RVEF) was investigated using fully automated RV quantification software, and how measurement values with 3DE data sets from the RVFV compare with those from the 4CV was determined. One hundred seventy-four patients who had undergone both cardiac magnetic resonance (CMR) and 3DE imaging were retrospectively selected. RV 3DE data sets were acquired from both the RVFV and the 4CV and were analyzed separately using fully automated RV quantification software. Primary end points were cardiac events, including cardiac death, heart failure requiring hospitalization, nonfatal myocardial infarction, and ventricular tachyarrhythmia. The feasibility of RVEF measurements on 3DE imaging from the RVFV and 4CV was 92% and 92%, respectively. There was good correlation (r=0.83) and small bias (0.3%) between RVEF from the RVFV and that from the 4CV. Similar results were obtained when only data from patients whose echocardiograms had poor image quality in one or both views were analyzed (r=0.83, bias=1.7%, n=78). Although fully automated analysis in both the RVFV and 4CV significantly underestimated RV volumes compared with CMR, neither measurement differed significantly for RVEF compared with CMR. During a median follow-up period of 12.5months, 21 patients experienced primary end points. RVEF assessed by CMR and 3DE imaging was significantly associated with cardiac events. RVEF using fully automated analysis had a significant association with cardiac events, even in patients with poor image quality (RVFV: hazard ratio, 0.90 [P=.009, n=44]; 4CV: hazard ratio, 0.90 [P=.009, n=68]). RV 3DE data sets from the RVFV and 4CV yielded similar RVEF values using fully automated software. RVEFs from both approaches had significant association with outcomes. Thus, both provide accurate information regarding RV function and risk for adverse outcomes.

Right ventricular three-dimensional echocardiography: the current status and future perspectives.

This review focused on right ventricular (RV) three-dimensional echocardiography (3DE) and discussed the following agenda. First, we summarized the clinical RV anatomy and function-related RV3DE use followed by the explanations about 3DSTE image acquisition, including pitfall. Next, we reviewed the reliability and feasibility of RV volume and RV ejection fraction measurements during the last decade. Besides, we described the techniques that might overcome the dropout images at RV anterior and out tract including the current limitations. Finally, speckle tracking echocardiography by RV3DE and novel RV shape assessment were reviewed. This review will help you get comprehensive information on the current status and future perspectives of RV3DE.

Machine Learning–Based Three-Dimensional Echocardiographic Quantification of Right Ventricular Size and Function: Validation Against Cardiac Magnetic Resonance

Three-dimensional echocardiography (3DE) allows accurate and reproducible measurements of right ventricular (RV) size and function. However, widespread implementation of 3DE in routine clinical practice is limited because the existing software packages are relatively time-consuming and skill demanding. The aim of this study was to test the accuracy and reproducibility of new machine learning- (ML-) based, fully automated software for three-dimensional quantification of RV size and function. Fifty-six unselected patients with a wide range of RV size and function and image quality, referred for clinically indicated cardiac magnetic resonance (CMR) imaging, underwent a transthoracic 3DE exam on the same day. End-systolic and end-diastolic RV volumes (ESV, EDV) and ejection fraction (EF) were measured using the ML-based algorithm and compared with CMR reference values using Bland-Altman and linear regression analyses. RV function quantification by echocardiography was feasible in all patients. The automatic approach was accurate in 32% patients with analysis time of 15±1seconds and 100% reproducible. Endocardial contour editing was necessary after the automated postprocessing in the remaining 68% patients, prolonging analysis time to 114±71seconds. With these minimal adjustments, RV volumes and EF measurements were accurate in comparison with CMR reference (biases: EDV, -25.6±21.1mL; ESV, -7.4±16mL; EF, -3.3%±5.2%) and showed excellent reproducibility reflected by coefficients of variation <7% and intraclass correlations ≥0.95 for all measurements. The new ML-based 3DE algorithm provided accurate and completely reproducible RV volume and EF measurements in one-third of unselected patients without any boundary editing. In the remaining patients, quick minimal editing resulted in reasonably accurate measurements with excellent reproducibility. This approach provides a promising solution for fast three-dimensional quantification of RV size and function.

Echocardiographic assessment of right ventricular systolic function

Assessment of right chamber function has become increasingly popular and important in recent decades, complementing the evaluation of left chamber functional parameters. The late adoption and integration of right ventricular (RV) function into a complete evaluation of cardiac function could be due in part to the difficulty in visualization of the whole right ventricle, inconsistency in the analysis of RV parameters, and poor understanding of the impact of RV function on prognosis. From M-mode to 2-dimensional (2D) measurements of RV size and function, there have been arrays of parameters that provide important information of the right ventricle. However, there are limitations of using 2D echocardiography to quantify RV volume and ejection fraction (EF), and currently accurate measurements of RV volumes and EF can be obtained using cardiac magnetic resonance (CMR) imaging. Using 3-dimensional echocardiography (3DE), the measurements of RV volumes and EF have become feasible and reproducible. Importantly, 3D measurements have been validated against CMR with higher correlation compared to 2D measurements. With the establishment of reference values, 3D echocardiography determined RV volumes and EF have the potential for better understanding of RV function and exploration of its significance for outcome research in various clinical scenarios.

Is Echocardiographic Assessment Right Ventricular Function Routinely Performed?

Assessment of right chamber function has become increasingly popular and important in recent decades, complementing the evaluation of left chamber functional parameters. The late adoption and integration of right ventricular (RV) function into a complete evaluation of cardiac function could be due in part to the difficulty in visualization of the whole right ventricle, inconsistency in the analysis of RV parameters, and poor understanding of the impact of RV function to prognosis. From M-mode to 2-dimensional (2D) measurements of RV size and function, several parameters, such as fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE) and RV free wall strain assessed by 2D speckle tracking echocardiography provide important information of the right ventricle. However, there are limitations of using 2D echocardiography to quantify RV volume and ejection fraction (EF), and currently accurate measurements of RV volumes and EF can be relied on cardiac magnetic resonance (CMR) imaging. CMR derived RVEF has been reported to provide incremental prognostic value over left ventricular ejection fraction in patients with idiopathic and ischemic dilated cardiomyopathy. With use of 3-dimensional (3D) echocardiography in conjunction with updated version of RV quantification software, the measurements of RV volumes and EF have become feasible and reproducible. It accuracy has been validated against CMR. With the establishment of reference values in the recent publications, 3D echocardiography determined RV volumes and EF have the potential for our better understanding of RV function and exploration of its significance for outcome research in various clinical scenarios. Thus, it is a prime time to assess RV function with 2D and preferentially 3D echocardiography in routine echocardiography examinations.

Three-Dimensional Speckle Tracking of the Right Ventricle: Toward Optimal Quantification of Right Ventricular Dysfunction in Pulmonary Hypertension

BackgroundQuantitative assessment of right ventricular (RV) systolic function largely depends on right ventricular ejection fraction (RVEF). Three-dimensional speckle tracking (3D-ST) has been used extensively to quantify left ventricular function, but its value for RV assessment has not been established. ObjectivesThis study sought to prospectively assess whether 3D-ST would be a reliable method for assessing RV systolic function and whether strain values were associated with survival. MethodsComprehensive 2-dimensional echocardiographic assessment, 3D-ST of the RV free wall, and measurement of RVEF was performed in 97 consecutive patients with established pulmonary hypertension (PHT) (RVEF 31.4 ± 9.6%, right ventricular systolic pressure [RVSP] 76.5 ± 26.2 mm Hg) and 60 healthy volunteers (RVEF 43.8 ± 9.4%, RVSP 25.9 ± 4.3 mm Hg). ResultsArea strain (AS) (−24.3 ± 7.3 vs. −30.8 ± 7.2; p < 0.001), radial strain (23.2 ± 14.4 vs. 34.9 ± 18.2; p < 0.001), longitudinal strain (LS) (−15.5 ± 3.8 vs. −17.9 ± 4.4; p = 0.001), and circumferential strain (CS) (−12.2 ± 4.5 vs. −15.7 ± 6.1; p < 0.001) were all reduced in patients with PHT, compared with normal individuals. AS and CS strongly correlated to RVEF (r = 0.851, r = −0.711; p < 0.001). Systolic dyssynchrony index was greater in PHT (0.14 ± 0.06 vs. 0.11 ± 0.07; p = 0.003) and correlated to RVEF (r = −0.563, p < 0.001). AS (hazard ratio [HR]: 3.49; 95% confidence interval [CI]: 1.21 to 7.07; p = 0.017), CS (HR: 4.17; 95% CI: 1.93 to 12.97; p < 0.001), LS (HR: 7.63; 95% CI: 1.76 to 10.27; p = 0.001), and RVEF (HR: 2.43; 95 CI: 1.00 to 5.92; p = 0.050) were significant determinants of all-cause mortality. Only AS (p = 0.029) and age (p = 0.087) were predictive of death after logistic regression analysis. ConclusionsPHT patients have reduced RV strain patterns and more dyssynchronous ventricles compared with controls, which was relatable to clinical outcomes. AS best correlated with RVEF and provides prognostic information independent of other variables.

My paper 20years later: Effect of positive end-expiratory pressure on right ventricular function in humans.

In 1992, we published a report on the effect of positive end-expiratory pressure (PEEP) on right ventricular (RV) function in humans. We measured RV volumes and pressures and pericardial pressure (Ppc) as PEEP was increased from zero to 15 cm H20 in 12 patients after thoracotomy, using a pulmonary arterial catheter equipped with a rapid responding thermistor that allowed measurement of RV ejection fraction (RVef), while Ppc was measured via a pericardial balloon catheter. RV end-diastolic volume (EDV) was estimated as the ratio of stroke volume (SV) to RVef, whereas RV end-systolic volume (ESV) were estimated as RV EDV-SV. PEEP increased Ppc and Pra, but RVef unaltered. There was no relation between either RV filling pressure (Pra-Ppc) and EDV or the change in RV filling pressure and EDV, although EDV varied significantly with PEEP (p<0.05). The relations between EDV and both SV and RVef were weak (r=0.54 and 0.55, respectively). RVef varied inversely with ESV (r=-0.77), although it showed no relation to transmural peak pulmonary artery pressure (r=0.28). However, both absolute and relative changes in EDV corresponded closely with respective ESV values (r=0.94). We concluded that EDV varies independently of changes in filling pressure and that changes in ESV occur independently of changes in ejection pressure. These data can be explained by assuming that the RV shape changes can dissociate changes in RV EDV from changes in RV wall stress (preload). Thus, changes in RV EDV may or may not alter SV but should proportionately change ESV to a degree dependent on election pressure and contractility. Subsequent studies confirmed our findings which can be summarized as 1) RV filling is independent of Pra; thus central venous pressure cannot be used to estimate RV preload; and 2) for cardiac output to increase by the Starling mechanism the RV must dilate increasing RV ESV. Since the pericardium limits absolute biventricular volume, there is a finite limit to which cardiac output can increase by the Starling mechanism defined not by left ventricular contractility but by RV function. And 3) if fluid loading causes Pra to increase without increasing cardiac output, then resuscitation should stop as the patient is going into acute cor pulmonale. These truths help bedside clinicians understand the echocardiographic and hemodynamic signatures of both RV failure and volume responsiveness.

Influence of right ventricular ejection fraction on the occurrence of arrhythmic events in patients with systolic dysfunction

Background Left ventricular ejection fraction (LVEF) is the primary risk stratification tool used for therapeutic decision making related to device therapy. However, an influence of right ventricular dysfunction on cardiovascular events is becoming apparent. The incremental prognostic value of right ventricular ejection fraction (RVEF) on future arrhythmic events among those being considered for device therapy has not been well examined. In this study we evaluate the significance of MRI-based measurement of RVEF versus other clinical and MRI-based variables for their ability to predict Sudden Cardiac Death (SCD) or Appropriate ICD therapy. Methods

Cost-Effective Design of Pulmonary Arterial Hypertension Trials To Detect Changes in Right Ventricular Size and Function: 3D Echocardiography Versus Cardiovascular Magnetic Resonance

Purpose Both cardiovascular magnetic resonance (CMR) and 3D transthoracic echocardiography (3DE) can quantify right ventricular (RV) end diastolic volume (EDV) and ejection fraction (EF) accurately. This study was designed to estimate sample sizes and imaging costs to detect changes in RV EDV and EF using 3DE and CMR for future pulmonary arterial hypertension (PAH) drug trials. Methods and Materials Same day CMR and 3DE were performed on 20 PAH patients (age: 53±13 yrs, 19 females) at 0 and 6 months. Consecutive short axis cines spanning the entire RV (Philips 1.5-T scanner) and full-volume acquisitions of the RV (Philips iE33+TomTec 4D RV-Function software) were used to measure EDV and EF. Sample size calculations using two-sample repeated measures to account for changes over time were performed modeling a placebo-controlled trial (Stata v12.1). Cost estimates were made using the 2012 Medicare physician fee schedule. Results No significant differences were noted between 0- and 6-month RV EF and EDV measurements with either CMR or 3DE, but the relatively large SDs reflected variable progression of disease in individual patients on standard therapy. Sample sizes required for 3DE were roughly 3 times greater than CMR. Although the per-study cost of CMR (~$400) is approximately double that of 3DE (~$200), the total cost of a trial using CMR is considerably lower. Conclusions Both CMR and 3DE can be used to detect the effects of new PAH therapies on RV EDV and EF, but CMR is more cost-effective. Population characteristics (average ± SD) Baseline 6 months CMR 3DE CMR 3DE RV EF (%) 34 ± 15 32 ± 12 36 ± 11 33 ± 9 RV EDV (mL) 245 ± 58 195 ± 59 244 ± 71 199 ± 48 Estimated per-group sample sizes (placebo-controlled trial - 90% power) Estimated cost (US$) CMR 3DE CMR 3DE EF: 3% change 54 169 89,000 143,000 EF: 5% change 20 61 33,000 52,000 RVEDV: 20 mL change 44 138 73,000 117,000 RVEDV: 30 mL change 20 61 33,000 52,000

Measurement of left and right ventricular volumes with tomographic equilibrium radionuclide angiocardiography and cardiac MRI

We previously developed an operator-interactive method for the measurement of left ventricular (LV) and right ventricular (RV) ejection fraction (EF) and end-systolic volume (ESV) and end-diastolic volume (EDV) using single-photon emission tomographic equilibrium radionuclide angiocardiography (SPECT ERNA). We aimed to compare our SPECT ERNA method with cardiac MRI (CMRI) for the determination of ventricular measures. Paired measurements of LV and RV EFs and ESV and EDV were carried out by SPECT ERNA and CMRI in a group of patients who had myocardial infarction due to left anterior descending coronary artery thrombosis. SPECT ERNA and CMRI provided similar estimations of the mean (SD) LV ESV [61 (23) vs. 61 (32) ml; P=0.99] and LV EDV [134 (29) vs. 141 (44) ml; P=0.28]. The mean (SD) LV EF by SPECT ERNA was slightly but significantly smaller than that by CMRI [0.55 (0.10) vs. 0.58 (0.11) ml; P=0.03]. SPECT ERNA, compared with CMRI, produced similar mean (SD) values of RV ESV [62 (17) vs. 67 (17) ml; P=0.10] and RV EDV [153 (28) vs. 149 (29) ml; P=0.51] and somewhat larger mean (SD) RV EF [0.60 (0.06) vs. 0.55 (0.06) ml; P<0.001]. Excellent correlations were found between SPECT ERNA and CMRI for combined LV ESV and EDV (R=0.85, P<0.001) and combined RV ESV and EDV (R=0.85, P<0.001). This study further validates SPECT ERNA as a method to measure LV and RV EF, ESV, and EDV.

Nonvolumetric Echocardiographic Indices of Right Ventricular Systolic Function: Validation with Cardiovascular Magnetic Resonance and Relationship with Functional Capacity

Right ventricular (RV) systolic function as measured by right ventricular ejection fraction (RVEF) has long been recognized as an important predictor of outcome in heart failure patients. The echocardiographic measurement of RV volumes and RVEF is challenging, however, owing to the unique geometry of the right ventricle. Several nonvolumetric echocardiographic indices of RV function have demonstrated prognostic value in heart failure. Comparison studies of these techniques with each other using RVEF as a benchmark are limited, however. Furthermore, the contribution of these various elements of RV function to patient functional status is uncertain. We therefore aimed to: (1) Determine which nonvolumetric echocardiographic index correlates best with RVEF as determined by cardiac magnetic resonance (CMR) imaging (the accepted gold standard measure of RV systolic function) and (2) Ascertain which echocardiographic index best predicts functional capacity. Eighty-three subjects (66 with systolic heart failure and 17 healthy controls) underwent CMR, 2D echocardiography, and cardiopulmonary exercise testing for comparison of echocardiographic indices of RV function with CMR RVEF, 6-minute walk distance and VO(2 PEAK). Speckle tracking strain RV strain exhibited the closest association with CMR RV ejection fraction. Indices of RV function demonstrated weak correlation with 6-minute walk distance, but basal RV strain rate by tissue velocity imaging had good correlation with VO(2 PEAK). Strain by speckle tracking echocardiography and strain rate by tissue velocity imaging may offer complementary information in the evaluation of RV contractility and its functional effects.

First-pass radionuclide cardiographic determination of right ventricular ejection fraction and pulmonary transit time: Reliability with and without background subtraction

Interrecording, interobserver, and intraobserver variability of three gamma camera methods (I, II, and III) in calculating right ventricular ejection fraction (RVEF) and a method for determination of mean pulmonary transit time (mPTT) were examined. The RVEF methods all employed ECG-gated recording of a99mtechnetium bolus in the 30° right anterior oblique position with separate end-diastolic and end-systolic right ventricular regions of interest (ROI); in method I, no background subtraction was performed; in method II, background subtraction was done by use of listmode recorded count rates in the right ventricular ROIs just prior to bolus arrival, and in method III a separate “background” ROI just below the right ventricle was used. In a tailored multiway analysis of variance, all three methods behaved statistically equally well with high reproducibility and no significant random or systematic variation. Interindividual range of RVEF values tended to be slightly higher, and systematic variation tended to be slightly lower for method III compared with methods I and II. In the inter- and intraobserver analyses, the mPTT method showed a high reproducibility, but there was a slight systematic increase from first to second recording. A plausible explanation and way of avoiding this phenomenon were identified. The gated first-pass technique with background subtraction allows reproducible repeated measurements of RVEF and mPTT.

Validation of echocardiographic indices of right ventriclular systolic function with cardiac magnetic resonance: a comparative study

Right ventricular ejection fraction (RVEF) is an important predictor of outcome in heart failure patients. Although cardiac magnetic resonance (CMR) assessment of RV function is considered gold standard and echocardiographic measurement of RVEF is challenging due to its unique geometry; CMR still has limited availability in the wider community. Therefore alternative echocardiographic indices such as tricuspid annular plane systolic excursion (TAPSE), peak tricuspid annular systolic velocity (RV S’) and RV fractional area change (RV FAC) have been evaluated and demonstrated prognostic value, however, comparison studies with RVEF by CMR are limited.

Extent of RV Dysfunction and Myocardial Infarction Assessed by CMR Are Independent Outcome Predictors Early After STEMI Treated With Primary Angioplasty

The aim of this study was to assess the prognostic value of right ventricular (RV) involvement diagnosed by cardiac magnetic resonance (CMR) early after ST-elevation myocardial infarction (STEMI). CMR allows accurate and reproducible RV assessment. However, there is a paucity of data regarding the prognostic value of RV involvement detected by CMR early after STEMI. Ninety-nine patients (77 men, mean age 57 ± 11 years) who underwent CMR 3 to 5 days after STEMI treated with primary angioplasty were followed for 1,150 ± 337 days for cardiac events (cardiac death, nonfatal myocardial infarction [MI], and hospitalizations due to decompensated heart failure). Cox proportional hazards model was applied in stepwise forward fashion to identify outcome predictors. Event-free survival was estimated by Kaplan-Meier method and compared between groups by the log-rank test. Cardiac events occurred in 34 patients (7 cardiac deaths, 8 MIs, 26 hospitalizations). By multivariable analysis, the independent outcome predictors were left ventricular (LV) MI transmurality index (hazard ratio: 1.03 per 1%; 95% confidence interval: 1.01 to 1.04; p = 0.001), RV ejection fraction (RVEF) (hazard ratio: 1.46 per 10% decrease; 95% confidence interval: 1.05 to 2.02; p = 0.03), and RVMI extent (hazard ratio: 1.50 per each infarcted RV segment; 95% confidence interval: 1.11 to 2.01; p = 0.007). Compared with clinical data (global chi-square = 5.2), LV ejection fraction [LVEF] (global chi-square = 11.1), RVEF (global chi-square = 17.1), LVMI transmural extent (global chi-square = 26.0), and RVMI extent (global chi-square = 34.9) improved outcome prediction in sequential Cox model analysis (p < 0.05 for all steps). RVEF stratified risk in patients with LVEF <40% in whom the 4-year event-free survival was 66.7% for RVEF ≥40% and 40.0% for RVEF <40% (p < 0.05). The extent of RVMI and RV dysfunction assessed early after STEMI are independent outcome predictors, which provide incremental prognostic value to clinical data, LV systolic function, and infarct burden. Measurement of RVEF may be particularly useful to stratify risk in patients with depressed LV function after STEMI.