Evaluation of aortic regurgitation in congenital heart disease: value of MR imaging in comparison to echocardiography

Quantitative evaluation of aortic valve regurgitation in 4D flow cardiac magnetic resonance: at which level should we measure?

PURPOSE

To find the best level to measure aortic flow for quantification of aortic regurgitation (AR) in 4D flow CMR.

METHODS

In 27 congenital heart disease patients with AR (67% male, 31 ± 16 years) two blinded observers measured antegrade, retrograde, net aortic flow volumes and regurgitant fractions at 6 levels in 4D flow: (1) below the aortic valve (AV), (2) at the AV, (3) at the aortic sinus, (4) at the sinotubular junction, (5) at the level of the pulmonary arteries (PA) and (6) below the brachiocephalic trunk. 2D phase contrast (2DPC) sequences were acquired at the level of PA. All patients received prior transthoracic echocardiography (TTE) with AR severity grading according to a recommended multiparametric approach.

RESULTS

After assigning 2DPC measurements into AR grading, agreement between TTE AR grading and 2DPC was good (κ = 0.88). In 4D flow, antegrade flow was similar between the six levels (p = 0.87). Net flow was higher at level 1-2 than at levels 3-6 (p < 0.05). Retrograde flow and regurgitant fraction at level 1-2 were lower compared to levels 3-6 (p < 0.05). Reproducibility (inter-reader agreement: ICC 0.993, 95% CI 0.986-0.99; intra-reader agreement: ICC 0.982, 95%CI 0.943-0.994) as well as measurement agreement between 4D flow and 2DPC (ICC 0.994; 95%CI 0.989 - 0.998) was best at the level of PA.

CONCLUSION

For estimating severity of AR in 4D flow, best reproducibility along with best agreement with 2DPC measurements can be expected at the level of PA. Measurements at AV or below AV might underestimate AR.

Prognostic value of depressed cardiac index after STEMI: a phase-contrast magnetic resonance study

AIMS 

An invasively measured cardiac index (CI) of ≤2.2 L/min/m2 is one of the strongest prognostic indicators after ST-elevation myocardial infarction (STEMI), however, knowledge is mainly based on invasive evaluations performed in the pre-stent era. Velocity-encoded phase-contrast cardiac magnetic resonance (PC-CMR) allows non-invasive determination of CI.

METHODS AND RESULTS 

In this prospective study, CMR was performed in 406 stable and contemporarily revascularized patients a median of 3 days after STEMI. Forward stroke volume was assessed at the level of the ascending aorta by PC-CMR. Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were determined by cine CMR. Major adverse cardiac events (MACE) were defined as the composite of death, myocardial infarction, or hospitalization for heart failure. Median CI was 2.52 L/min/m2 and 27% of patients had ≤2.2 L/min/m2. Median LVEF was 53% and median GLS was -12.2%. During a median follow-up of 14.2 [95% confidence interval (95% CI) 13.6-14.7] months, 41 patients (10.1%) experienced a MACE. A depressed CI was significantly associated with MACE after adjustment for LVEF, GLS, Thrombolysis in Myocardial Infarction (TIMI) risk score, and infarct size [hazard ratio = 3.15 (95% CI 1.53-6.47); P = 0.002] and led to significant discrimination improvement [net reclassification improvement 0.61 (95% CI 0.25-0.97); P < 0.001].

CONCLUSIONS 

A CI of 2.2 L/min/m2 or less as measured by PC-CMR was present in 27% of clinically stable patients after STEMI and strongly and independently predicted medium-term MACE. The prognostic value of a depressed CI was superior and incremental to LVEF, GLS, TIMI risk score, and infarct size.

Optimal Management of Chronic Severe Aortic Regurgitation - How to Determine Cutoff Values for Surgical Intervention?

Aortic regurgitation (AR) is a common valvular heart disease, but the optimal timing of surgical intervention remains controversial. In the natural history of chronic severe AR, sudden death is rare, and the annual mortality rate is comparatively low. Considering the hemodynamic features of combined volume and pressure overload and long-term compensation in patients with chronic AR, symptoms related to AR do not frequently occur. Therefore, the progression of left ventricular (LV) dysfunction is a key factor in determining the timing of surgical intervention in patients with severe chronic AR. In addition to symptoms, an ejection fraction <50% and an LV endsystolic diameter (LVESD) >45 mm are appropriate cutoff values for surgical intervention in Japanese patients, whereas LV end-diastolic diameter is not a good indicator. An LVESD index of 25 mm/m²is controversial, because adjusting for body size may cause overcorrection in Japanese patients who have a small body size compared with Westerners. Accumulation of data from the Japanese population is indispensable for establishing guidelines on optimal management of patients with chronic AR.

The cardiovascular determinants of physical function in patients with end-stage kidney disease on haemodialysis

Patients with end-stage kidney disease (ESKD) are often sedentary and decreased functional capacity associates with mortality. The relationship between cardiovascular disease (CVD) and physical function has not been fully explored. Understanding the relationships between prognostically relevant measures of CVD and physical function may offer insight into how exercise interventions might target specific elements of CVD. 130 patients on haemodialysis (mean age 57 ± 15 years, 73% male, dialysis vintage 1.3 years (0.5, 3.4), recruited to the CYCLE-HD trial (ISRCTN11299707), underwent cardiovascular phenotyping with cardiac MRI (left ventricular (LV) structure and function, pulse wave velocity (PWV) and native T1 mapping) and cardiac biomarker assessment. Participants completed the incremental shuttle walk test (ISWT) and sit-to-stand 60 (STS60) as field-tests of physical function. Linear regression models identified CV determinants of physical function measures, adjusted for age, gender, BMI, diabetes, ethnicity and systolic blood pressure. Troponin I, PWV and global native T1 were univariate determinants of ISWT and STS60 performance. NT pro-BNP was a univariate determinant of ISWT performance. In multivariate models, NT pro-BNP and global native T1 were independent determinants of ISWT and STS60 performance. LV ejection fraction was an independent determinant of ISWT distance. However, age and diabetes had the strongest relationships with physical function. In conclusion, NT pro-BNP, global native T1 and LV ejection fraction were independent CV determinants of physical function. However, age and diabetes had the greatest independent influence. Targeting diabetic care may ameliorate deconditioning in these patients and a multimorbidity approach should be considered when developing exercise interventions.

Pure Aortic Regurgitation in Pediatric Patients

Aortic regurgitation (AR) continues to be an important cause of morbidity and mortality in pediatric patients. Although echocardiographic parameters are well established for the adults, there are no clear cut-off values for AR severity in children. Cardiac magnetic resonance (CMR) imaging is considered a "gold standard" for a quantitative evaluation of the AR, but it is not widely available. This study assesses which echo parameter can accurately define AR severity as assessed by CMR in pediatric patients. A total of 27 pediatric patients (12 ± 3 years, range 6 to 18 years) with different degree of AR underwent echo assessment within an average of 35 days from CMR. CMR included phase-contrast velocity-encoded imaging for the measurement of regurgitant fraction (RF). Severe AR was defined as RF >33%. Echo evaluation included vena contracta, pressure half time, the ratio between the AR jet and the left ventricular outflow tract diameter (jet/left ventricular outflow tract), presence of holodiastolic reversal flow in abdominal aorta, the ratio between the velocity-time integral of the reversal flow over the forward flow in descending aorta (echoRF). Among the studied parameters, the strongest predictor of severe AR, as assessed by CMR, was echoRF. Receiver-operating characteristic curve showed, for a cutoff >0.38, an area under the curve of 0.886 (p <0.0001), a sensitivity of 71%, and a specificity of 100%. Correlation coefficient between echoRF and RF was R = 0.929 (p <0.0001). In conclusion, echoRF is a strong echo-Doppler marker of severe AR in the pediatric population. This parameter should be routinely added in the standard echo evaluation of pediatric patients with AR.

Aortic regurgitation assessment by cardiovascular magnetic resonance imaging and transthoracic echocardiography: intermodality disagreement impacting on prediction of post-surgical left ventricular remodeling

Transthoracic echocardiography (TTE) is the primary clinical imaging modality for the assessment of patients with isolated aortic regurgitation (AR) in whom TTE's linear left ventricular (LV) dimension is used to assess disease severity to guide aortic valve replacement (AVR), yet TTE is relatively limited with regards to its integrated semi-quantitative/qualitative approach. We therefore compared TTE and cardiovascular magnetic resonance (CMR) assessment of isolated AR and investigated each modality's ability to predict LV remodeling after AVR. AR severity grading by CMR and TTE were compared in 101 consecutive patients referred for CMR assessment of chronic AR. LV end-diastolic diameter and end-systolic diameter measurements by both modalities were compared. Twenty-four patients subsequently had isolated AVR. The pre-AVR estimates of regurgitation severity by CMR and TTE were correlated with favorable post-AVR LV remodeling. AR severity grade agreement between CMR and TTE was moderate (ρ = 0.317, P = 0.001). TTE underestimated CMR LV end-diastolic and LV end-systolic diameter by 6.6 mm (P < 0.001, CI 5.8-7.7) and 5.9 mm (P < 0.001, CI 4.1-7.6), respectively. The correlation of post-AVR LV remodeling with CMR AR grade (ρ = 0.578, P = 0.004) and AR volumes (R = 0.664, P < 0.001) was stronger in comparison to TTE (ρ = 0.511, P = 0.011; R = 0.318, P = 0.2). In chronic AR, CMR provides more prognostic relevant information than TTE in assessing AR severity. CMR should be considered in the management of chronic AR patients being considered for AVR.

Cardiac Magnetic Resonance Imaging Versus Transthoracic Echocardiography for Prediction of Outcomes in Chronic Aortic or Mitral Regurgitation

In subjects with aortic regurgitation (AR) or mitral regurgitation (MR), transthoracic echocardiography (TTE) is recommended for surveillance. Few prospective studies have directly compared the ability of TTE and cardiac magnetic resonance (CMR) to predict clinical outcomes in AR and MR. We hypothesized that, given its higher reproducibility, CMR would predict the need for valve surgery or heart failure (HF) hospitalization better than TTE. Quantitative TTE and CMR were performed on the same day for 51 subjects: 29 with chronic AR and 22 with chronic, primary MR for quantification of valve regurgitation. Baseline measurements of valve regurgitation were compared to the combined primary end point of new HF and valve surgery using receiver operating characteristics, simple logistic regression, and Kaplan-Meier survival analyses. The primary end point occurred in 5 AR subjects (all surgery) and 8 MR subjects (7 surgery, 1 HF) after a mean follow-up of 4.4 ± 1.5 years. For AR, CMR-derived regurgitant volume >50 ml identified those at high risk with 50% undergoing valve surgery versus 0% for those with regurgitant volume ≤50 ml and was more strongly associated with outcomes than regurgitant volume by TTE (p <0.05). For MR, 6.8% of those with regurgitant volume by TTE ≤30 ml developed the primary end point versus 70% in those with regurgitant volume >30 ml. Regurgitant volume by CMR showed no significant separation of survival curves for MR. In conclusion, regurgitant volume by CMR was more predictive of outcomes than by TTE in subjects with AR. In MR, the 2 methods performed similarly.

Left ventricular mass and systolic function in children with chronic kidney disease-comparing echocardiography with cardiac magnetic resonance imaging

BACKGROUND

Increased left ventricular mass (LVM) is an important risk marker of uremic cardiovascular disease. Calculation of LVM by echocardiography (Echo) relies on geometric assumptions and in adults on hemodialysis overestimates LVM compared to cardiac magnetic resonance (CMR). We compare both techniques in children with chronic kidney disease (CKD).

METHODS

Concurrent Echo and CMR was performed in 25 children with CKD (14 after kidney transplantation) aged 8-17 years.

RESULTS

Compared to normal children, CMR-LVM was increased (standard deviation score (SDS) 0.39 ± 0.8 (p = 0.03)), stroke volume and cardiac output decreased (SDS -1.76 ± 1.1, p = 0.002 and -1.11 ± 2.0, p = 0.001). CMR-LVM index but not Echo-LVMI correlated to future glomerular filtration rate (GFR) decline (r = -0.52, p = 0.01). Mean Echo-LVM was higher than CMR-LVM (117 ± 40 vs. 89 ± 29 g, p < 0.0001), with wide limits of agreement (-6.2 to 62.8 g). The Echo-CMR LVM difference increased with higher Echo-LVMI (r = 0.77, p < 0.0001). Agreement of classifying left ventricular hypertrophy was poor with Cohen's kappa of 0.08. Mean Echo and CMR-ejection fraction differed by 1.42% with wide limits of agreement (-12.6 to 15.4%).

CONCLUSIONS

Echo overestimates LVM compared to CMR, especially at higher LVM. Despite this, CMR confirms increased LVM in children with CKD. Only CMR-LVMI but not Echo-LVMI correlated to future GFR decline.

Quantitation of mitral regurgitation after percutaneous MitraClip repair: comparison of Doppler echocardiography and cardiac magnetic resonance imaging

OBJECTIVE

Percutaneous valve intervention for severe mitral regurgitation (MR) using the MitraClip is a novel technology. Quantitative assessment of residual MR by transthoracic echocardiography (TTE) is challenging, with multiple eccentric jets and artifact from the clips. Cardiovascular magnetic resonance (CMR) is the reference standard for left and right ventricular volumetric assessment. CMR phase-contrast flow imaging has superior reproducibility for quantitation of MR compared to echocardiography. The objective of this study was to establish the feasibility and reproducibility of CMR in quantitating residual MR after MitraClip insertion in a prospective study.

METHODS

Twenty-five patients underwent successful MitraClip insertion. Nine were excluded due to non-magnetic resonance imaging (MRI) compatible implants or arrhythmia, leaving 16 who underwent a comprehensive CMR examination at 1.5 T (Siemens Aera) with multiplanar steady state free precession (SSFP) cine imaging (cine CMR), and phase-contrast flow acquisitions (flow CMR) at the mitral annulus atrial to the MitraClip, and the proximal aorta. Same-day echocardiography was performed with two-dimensional (2D) visualization and Doppler. CMR and echocardiographic data were independently and blindly analyzed by expert readers. Inter-rater comparison was made by concordance correlation coefficient (CCC) with 95% confidence intervals (CIs), and Bland-Altman (BA) methods.

RESULTS

Mean age was 79 years, and mean LVEF was 44%±11% by CMR and 54%±16% by echocardiography. Inter-observer reproducibility of echocardiographic visual categorical grading by expert readers was poor, with a CCC of 0.475 (-0.7, 0.74). Echocardiographic Doppler regurgitant fraction reproducibility was modest (CCC 0.59, 0.15-0.84; BA mean difference -3.7%, -38% to 31%). CMR regurgitant fraction reproducibility was excellent (CCC 0.95, 0.86-0.98; BA mean difference -2.4%, -11.9 to 7.0), with a lower mean difference and narrower limits of agreement compared to echocardiography. Categorical severity grading by CMR using published ranges had good inter-observer agreement (CCC 0.86, 0.62-0.95).

CONCLUSIONS

CMR performs very well in the quantitation of MR after MitraClip insertion, with excellent reproducibility compared to echocardiographic methods. CMR is a useful technique for the comprehensive evaluation of residual regurgitation in patients after MitraClip. Technical limitations exist for both techniques, and quantitation remains a challenge in some patients.

Assessment of Paravalvular Regurgitation Following Transcatheter Aortic Valve Replacement

Paravalvular regurgitation (PVR) following transcatheter aortic valve replacement is a known complication associated with poorer outcomes. This article discusses the current techniques for assessing the severity of PVR, including angiography, hemodynamics, MRI, and echocardiography. The strengths and pitfalls of each modality are reviewed.

2014 korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the korean society of cardiology and the korean society of radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

2014 Korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the Korean Society of Cardiology and the Korean Society of Radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

Direct measurement of aortic regurgitation with phase-contrast magnetic resonance is inaccurate: proposal of an alternative method of quantification

BACKGROUND

Phase-contrast magnetic resonance (MR) has been widely used for quantification of aortic regurgitation. However there is significant practice variability regarding where and how the blood flow data are acquired.

OBJECTIVE

To compare the accuracy of flow quantification of aortic regurgitation at three levels: the ascending aorta at the level of the right pulmonary artery (level 1), the aortic valve hinge points at end-diastole (level 2) and the aortic valve hinge points at end-systole (level 3).

MATERIALS AND METHODS

We performed cardiovascular MR in 43 children with aortic regurgitation. By using phase-contrast MR, we measured the systolic forward, diastolic retrograde and net forward flow volume indices at three levels. At each level, the following comparisons were made: (1) systolic forward flow volume index (FFVI) versus left ventricular cardiac index (LVCI) measured by cine ventricular volumetry; (2) retrograde flow volume index (RFVI) versus estimated aortic regurgitation volume index (which equals LVCI minus pulmonary blood flow index [QPI]); (3) net forward flow volume index (NFVI) versus pulmonary blood flow index.

RESULTS

The forward flow volume index, retrograde flow volume index and net forward flow volume index measured at each of the three levels were significantly different except for the retrograde flow volume index measured at levels 1 and 3. There were good correlations between the forward flow volume index and the left ventricular cardiac index at all three levels, with measurement at level 2 showing the best correlation. Compared to the forward flow volume indices, the retrograde flow volume index had a lower correlation with the estimated aortic regurgitation volume indices and had widely dispersed data with larger prediction intervals.

CONCLUSION

Large variations in systolic forward, diastolic retrograde and net forward flow volumes were observed at different levels of the aortic valve and ascending aorta. Direct measurement of aortic regurgitation volume and fraction is inaccurate and should be abandoned. Instead, calculation of the aortic regurgitation volume from more reliable data is advised. We recommend subtracting pulmonary blood flow from systolic forward flow measured at the aortic valve hinge points at end-diastole as a more accurate and consistent method for calculating the volume of aortic regurgitation.

The role of cardiac magnetic resonance in valvular heart disease

The prevalence of valvular heart disease is increasing as the population ages. In diagnosing individuals with valve disease, echocardiography is the primary imaging modality used by clinicians both for initial assessment and for longitudinal evaluation. However, in some cases cardiovascular magnetic resonance has become a viable alternative in that it can obtain imaging data in any plane prescribed by the scan operator, which makes it ideal for accurate investigation of all cardiac valves: aortic, mitral, pulmonic, and tricuspid. In addition, CMR for valve assessment is noninvasive, free of ionizing radiation, and in most instances does not require contrast administration. The objectives of a comprehensive CMR study for evaluating valvular heart disease are threefold: (1) to provide insight into the mechanism of the valvular lesion (via anatomic assessment), (2) to quantify the severity of the valvular lesion, and (3) to discern the consequences of the valvular lesion.

Prognostic value of cardiac magnetic resonance imaging in patients with aortic regurgitation

Guidelines on valve replacement recommend aortic valve replacement for patients with severe aortic regurgitation (AR) with symptoms or left ventricular (LV) dysfunction. However, the optimal timing of surgery for asymptomatic AR patients without LV dilation or dysfunction is not known. There are data to suggest that excess volume load imposed by AR may not only produce subclinical LV dysfunction, but produce neurohormonal activation similar to the heart failure syndrome resulting in reduced survival. The study by Myerson et al. is the first to investigate the predictive ability of cardiac MRI (CMR) for the outcome of asymptomatic patients with AR. They studied 113 asymptomatic patients with moderate-to-severe AR on echocardiography in four centers. A total of 39 (35%) patients developed symptoms or an indication for surgery over a mean follow-up period of 2.6 years. AR volume, AR regurgitant fraction, LV end-diastolic and end-systolic volumes had high discriminatory powers (area under curve of 0.96, 0.93, 0.88 and 0.78, respectively) to predict these events. Higher association with the outcome was observed when LV end-diastolic volume and regurgitant fraction were combined. A significantly higher number of patients with regurgitant fraction >33% were likely to progress to surgery compared with patients with a regurgitant fraction of <33% (85 vs 8%; p < 0.001). These results demonstrate a potential role for CMR for risk stratification of patients with asymptomatic moderate or severe AR, given the ability of CMR to accurately quantify AR and LV volumes. Based on the data presented, it is possible that we may be waiting too long to offer surgery in patients with severe AR.

Guidelines and protocols for cardiovascular magnetic resonance in children and adults with congenital heart disease: SCMR expert consensus group on congenital heart disease

Cardiovascular magnetic resonance (CMR) has taken on an increasingly important role in the diagnostic evaluation and pre-procedural planning for patients with congenital heart disease. This article provides guidelines for the performance of CMR in children and adults with congenital heart disease. The first portion addresses preparation for the examination and safety issues, the second describes the primary techniques used in an examination, and the third provides disease-specific protocols. Variations in practice are highlighted and expert consensus recommendations are provided. Indications and appropriate use criteria for CMR examination are not specifically addressed.

Evaluation of the aortic and mitral valves with cardiac computed tomography and cardiac magnetic resonance imaging

Cardiac computed tomography (CT) produces high-quality anatomical images of the cardiac valves and associated structures. Cardiac magnetic resonance imaging (MRI) provides images of valve morphology, and allows quantitative evaluation of valvular dysfunction and determination of the impact of valvular lesions on cardiovascular structures. Recent studies have demonstrated that cardiac CT and MRI are important adjuncts to echocardiography for the evaluation of aortic and mitral valvular heart diseases (VHDs). Radiologists should be aware of the technical aspects of cardiac CT and MRI that allow comprehensive assessment of aortic and mitral VHDs, as well as the typical imaging features of common and important aortic and mitral VHDs on cardiac CT and MRI.

Cardiac imaging in valvular heart disease

The aim of this article is to provide a perspective on the relative importance and contribution of different imaging modalities in patients with valvular heart disease. Valvular heart disease is increasing in prevalence across Europe, at a time when the clinical ability of physicians to diagnose and assess severity is declining. Increasing reliance is placed on echocardiography, which is the mainstay of cardiac imaging in valvular heart disease. This article outlines the techniques used in this context and their limitations, identifying areas in which dynamic imaging with cardiovascular magnetic resonance and multislice CT are expanding.

3D color-Doppler echocardiography and chronic aortic regurgitation: a novel approach for severity assessment

BACKGROUND

3D echocardiography provides a complete evaluation of the aortic valve and adjacent structures and it improves the assessment of this cardiac region. Three-dimensional color-Doppler echocardiography (3DCDE) evaluation might improve the measurements of the functional regurgitant orifice in patients with Chronic Aortic Regurgitation (CAR).

OBJECTIVES

Our aim was to compare the accuracy of current echo-Doppler methods and 3DCDE for the assessment of CAR severity. The reference method used in this work was the CAR severity determined by means of cardiac magnetic resonance (CMR) METHODS: Thirty-two consecutive patients with an established diagnosis of CAR recruited in our institution comprised our study group. CAR severity was determined by conventional Echo-Doppler methods and by 3DCDE and their results were compared with those obtained by means of CMR.

RESULTS

Mean age was 63.0 ± 13.5 years. Twenty-two patients (68.8%) were men. Compared with the traditional echo-Doppler methods, 3DCDE evaluation had the best linear association with CMR results (3D vena contracta cross sectional area method: r = 0.88; r square = 0.77; p < 0.001. 3D vena contracta cross sectional area/left ventricular outflow tract cross sectional area method: r = 0.87; r square = 0.75; p < 0.001). The ROC analysis showed an excellent area under curve for detection of severe CAR (3D vena contracta cross sectional area method = 0.97; 3D vena contracta cross sectional area/left ventricular outflow tract cross sectional area method = 0.98). Inter- and intra-observer variability for the 3DCDE evaluation was good (ICC = 0.89 and ICC = 0.91 for inter and intra observer variability respectively).

CONCLUSIONS

3DCDE is an accurate and highly reproducible diagnostic tool for estimating CAR severity. Compared with the traditional echo-Doppler methods, 3DCDE has the best agreement with the CMR determined CAR severity. Thus, 3DCDE is a diagnostic method that may improve the therapeutic management of patients with CAR.

An echocardiographic model predicting severity of aortic regurgitation in congenital heart disease

Background- Multiple echocardiographic parameters have been identified to predict the severity of aortic regurgitation (AR) with variable reliability. This study was performed to identify which echocardiographic parameters best predict the severity of AR in a cohort of patients with congenital heart disease, using cardiovascular MRI quantification as a reference standard. Methods and Results- The study involved 2 phases. In phase 1, predictive models were developed on the basis of multivariable analysis of various morphometric and Doppler variables obtained from 174 echocardiograms that best predicted the severity of AR as defined by paired cardiovascular MRI examinations. A nonlinear estimate of regurgitation fraction, using the variables parasternal vena contracta-derived area divided by body surface area and abdominal aorta Doppler retrograde velocity-time integral divided by antegrade velocity-time integral, was identified through multivariable analysis as the best predictive model for AR fraction. In phase 2, the predictive models were prospectively tested on 43 echocardiographic examinations for which a paired cardiovascular MRI was performed. The agreement between the observed and predicted AR fraction was assessed using Bland-Altman analysis. For the 30 studies of the validation data set that had adequate quality images of both the parasternal vena contracta width and the abdominal aorta flow profile, the predicted AR values had a mean bias±SD of 0.4±7.3% (P=0.80). Conclusions- A model using the 2 variables parasternal vena contracta-derived area divided by body surface area and abdominal aorta Doppler retrograde velocity-time integral divided by antegrade velocity-time integral can predict AR severity in patients with a wide variety of congenital heart disease.

Qualitative echocardiographic assessment of aortic valve regurgitation with quantitative cardiac magnetic resonance: a comparative study

This study examined the correlation of echocardiography (ECHO) and Cardiac Magnetic Resonance (CMR) in the assessment of aortic valve regurgitation (AR) in children and young adults with congenital heart disease. We hypothesized that qualitative ECHO assessment correlates insufficiently with quantitative CMR data and compared subjective ECHO evaluations with objective measurement of regurgitant fractions (RF) by CMR. Patients who had both ECHO and CMR assessments of AR within 60 days of each other were included. The qualitative ECHO assessment (mild, moderate, severe) of AR and left ventricular dimension at end diastole were recorded. RF was quantified by CMR using phase-contrast velocity mapping. Repeat ECHO review and grading of AR was performed by a blinded single reader in a randomly chosen subgroup of patients. In 43 patients studied, statistical significance was observed in the CMR-RF between mild and moderate, and between mild and severe ECHO grades. There was significant overlap of objective RF between subjective grades. Mild ECHO AR corresponded to an RF (%) of 0-29, moderate 1-40, and severe 5-58. Overlap was more significant at moderate and severe grades. Results were similar in the group in whom a single reader interpreted the ECHO assessment. In conclusion, results derived from a real-life multiple-reader ECHO laboratory showed inconsistencies in ECHO grading of AR, with a wide range of objectively measured RF within a given ECHO grade. ECHO is less reliable in identifying more severe AR, often overestimating severity. Quantitative CMR is a potentially useful supplement to ECHO for management decisions and assessments of medical and surgical therapies in children and young adults with AR.

Hemodynamic evaluation of aortic regurgitation by magnetic resonance imaging

Magnetic resonance imaging was compared with echocardiography and angiography in determining the regurgitant volume in patients with aortic regurgitation. Forty patients were examined at 1.5 T. The regurgitant jet was located using a gradient-echo sequence. Cine measurements were performed to calculate left ventricular function. For flow evaluation, a velocity-encoded breath-hold phase-difference magnetic resonance sequence was used. The degree of aortic regurgitation assessed by magnetic resonance imaging agreed with that of angiography in 28 of 40 (70%) patients, and with the echocardiography result in 80%. Correlation between calculated stroke volume by magnetic resonance cine and flow measurements was very good (r > 0.9). Magnetic resonance imaging enables quick and reliable quantitative assessment of aortic regurgitant volume, and it might be the optimal technique for multiple follow-up studies and assessment of left ventricular function, leading to better evaluation of disease severity and optimization of the timing of valve surgery.