Evolution of right ventricular size over time after tetralogy of Fallot repair: a longitudinal cardiac magnetic resonance study.

AIMS: It is commonly believed that pulmonary regurgitation (PR) after surgical repair of tetralogy of Fallot (TOF) leads to progressive right ventricular (RV) enlargement. However, progressive RV dilatation has never clearly been documented in this patient population. Therefore, we studied the size of the RV over time in patients after surgical TOF repair. METHODS AND RESULTS: Fifty-one consecutive patients after surgical TOF repair underwent at least two cardiovascular magnetic resonance (CMR) exams using a single CMR scanner. Patients with RV outflow tract obstruction, interventions other than the initial repair and CMR exams with use of sedation were excluded. Three subgroups with different repair techniques were studied: transannular patch repair [n = 22, age 17 ± 10 years], subvalvular patch repair [n = 15, age 22 ± 8 years], or non-patch repair/infundibulectomy (n = 14, age 28 ± 11 years). Right ventricular end-diastolic volume index (RVEDVI) and PR fraction did not change during the 37 ± 21 months follow-up between first and last CMR in the whole group (RVEDVI: 118 ± 23 mL/m2 vs. 119 ± 23 mL/m2, P = 0.720; PR fraction: 33% (23-40%) vs. 32% (24-39%), P = 0.268). RVEDVI remained stable in all subgroups (transannular patch: 120 ± 21 mL/m2 vs. 122 ± 22 mL/m2, subvalvular patch: 112 ± 23 mL/m2 vs. 111 ± 23 mL/m2, non-patch: 123 ± 28 mL/m2 vs. 123 ± 23 mL/m2, P = 0.827). RVEDVI at last CMR did not differ between groups (P = 0.301). CONCLUSIONS: This study shows no progression of RV dilatation in patients after surgical repair of TOF with moderately dilated RVs and significant PR during a 3-year follow-up. RV dilatation in our patient group seems to be independent from surgical repair techniques.

Comparison of MR flow quantification in peripheral and main pulmonary arteries in patients after right ventricular outflow tract surgery: A retrospective study.

PURPOSE: To compare the quantification of pulmonary stroke volume (SV) by phase contrast magnetic resonance (PC-MR) in the main pulmonary artery (MPA) to the sum of SVs in both peripheral pulmonary arteries (PPA) in different right ventricular (RV) outflow pathologies. MATERIALS AND METHODS: Pulmonary SV was determined by PC-MR in the MPA and the PPA in healthy individuals (H, n = 54), patients after correction for tetralogy of Fallot with significant pulmonary regurgitation and without pulmonary or RV outflow tract stenosis (PR, n = 50), and in patients with RV outflow tract or pulmonary valve stenosis (PS, n = 50). Resulting SVs were compared to aortic SV in the ascending aorta. RESULTS: Mean age was similar between the groups: H 28 ± 17 vs. PR 24 ± 11 vs. PS 22 ± 10 years. Bland-Altman analyses revealed in all groups a relatively small systemic (bias) but large random error (limits of agreement) for pulmonary SV determined in the MPA as compared to summed SVs in the PPA. The largest limits of agreement were present in PS patients: H: MPA 3.9% (-11, + 19) vs. PPA 0.4% (-15, + 15); PR: MPA 5.2% (-25, + 36) vs. PPA 0.6% (-24, + 26); PS: MPA 5% (-36; + 46), PPA -0.03% (-34, + 35). CONCLUSION: The accuracy of PC-MR in the MPA is reasonable; however, a large random error (precision) is observed that is most pronounced in PS patients. This potential error should be taken into consideration when interpreting MPA flow measurements. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1839-1845.

Cardiovascular magnetic resonance is successfully feasible in many patients aged 3 to 8years without general anesthesia or sedation.

OBJECTIVES: Patients younger than 8 years are usually examined by cardiovascular magnetic resonance (CMR) under general anesthesia (GA) or sedation without intubation. Therefore, we sought to study the feasibility of CMR in patients aged 3 to 8years without GA or sedation. PATIENTS: Data sets of 71 consecutive patients aged 3 to 8years were studied retrospectively. DESIGN: The total cohort was divided into 2 groups: a no-GA or sedation without intubation group (no-GA or sedation) and a GA or sedation without intubation group (GA or sedation). MEASUREMENTS: The patients' age, scan durations for each group, successfully answered clinical question, and number of sequences per study were compared between both groups. MAIN RESULTS: Scan duration in the no-GA or sedation group (n=44) was 35± 20minutes, and that in the GA or sedation group (n=27) was 60± 31minutes (P<.001). The percentage of successful reports was 95% (42/44) in the no-GA or sedation group and 89% (24 of 27) in the GA or sedation group (P=.29). CONCLUSION: CMR in patients aged 3 to 8years is usually successfully feasible without GA or sedation.

Asymmetric Dimethylarginine Stimulates Akt1 Phosphorylation via Heat Shock Protein 70-Facilitated Carboxyl-Terminal Modulator Protein Degradation in Pulmonary Arterial Endothelial Cells.

Asymmetric dimethylarginine (ADMA) induces the mitochondrial translocation of endothelial nitric oxide synthase (eNOS) through the nitration-mediated activation of Akt1. However, it is recognized that the activation of Akt1 requires phosphorylation events at threonine (T) 308 and serine (S) 473. Thus, the current study was performed to elucidate the potential effect of ADMA on Akt1 phosphorylation and the mechanisms that are involved. Exposure of pulmonary arterial endothelial cells to ADMA enhanced Akt1 phosphorylation at both threonine 308 and Ser473 without altering Akt1 protein levels, phosphatase and tensin homolog activity, or membrane Akt1 levels. Heat shock protein (Hsp) 90 plays a pivotal role in maintaining Akt1 activity, and our results demonstrate that ADMA decreased Hsp90-Akt1 interactions, but, surprisingly, overexpression of a dominant-negative Hsp90 mutant increased Akt1 phosphorylation. ADMA exposure or overexpression of dominant-negative Hsp90 increased Hsp70 levels, and depletion of Hsp70 abolished ADMA-induced Akt1 phosphorylation. ADMA decreased the interaction of Akt1 with its endogenous inhibitor, carboxyl-terminal modulator protein (CTMP). This was mediated by the proteasomal-dependent degradation of CTMP. The overexpression of CTMP attenuated ADMA-induced Akt1 phosphorylation at Ser473, eNOS phosphorylation at Ser617, and eNOS mitochondrial translocation. Finally, we found that the mitochondrial translocation of eNOS in our lamb model of pulmonary hypertension is associated with increased Akt1 and eNOS phosphorylation and reduced Akt1-CTMP protein interactions. In conclusion, our data suggest that CTMP is directly involved in ADMA-induced Akt1 phosphorylation in vitro and in vivo, and that increasing CTMP levels may be an avenue to treat pulmonary hypertension.

Non-volumetric echocardiographic indices and qualitative assessment of right ventricular systolic function in Ebstein's anomaly: comparison with CMR-derived ejection fraction in 49 patients.

AIMS: Ebstein's anomaly (EA) is often associated with right ventricular (RV) dysfunction. Data on echocardiographic quantification of RV function are, however, rare. The aim of this study was to determine how non-volumetric echocardiographic indices and qualitative assessment of global systolic RV function correlate with cardiovascular magnetic resonance (CMR)-derived RV ejection fraction (EF). METHODS AND RESULTS: We compared six echocardiographic indices and qualitative assessment of RV function with the gold standard CMR. A total of 49 unoperated patients with EA and a mean age of 32 ± 18 years were examined. Tricuspid annular plane systolic excursion, tissue Doppler myocardial velocities (peak S and IVA) and 2D strain and strain rate measures for the RV were compared with CMR-derived EF. Only 2D global longitudinal strain (2D-GLS), out of the six parameters investigated, showed a weak, although statistically significant correlation with CMR-derived RVEF (R = -0.4, P = 0.01). Using a cut-off value of -20.15, 2D-GLS sensitivity (77%) and specificity (46%) in detecting patients with a CMR-derived EF of <50% were comparable with qualitative assessment (sensitivity 77%, specificity 45%). CONCLUSION: Overall echocardiographic parameters of RV function correlate poorly with CMR-derived EF in patients with EA. Only 2D global longitudinal RV strain correlated weakly with CMR-derived RVEF. However, the sensitivity and specificity for detecting RV dysfunction using 2D strain imaging were comparable with qualitative RV functional assessment.

Cardiovascular magnetic resonance techniques and findings in children with myocarditis: a multicenter retrospective study.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is increasingly used to diagnose myocarditis in adults but its use in children is not well-established. We sought to describe the presentation, CMR protocol and findings, and outcomes in a multicenter cohort of children with myocarditis. METHODS: Thirteen hospitals retrospectively identified patients meeting the following inclusion criteria: 1) diagnosis of myocarditis by the managing physicians, 2) age <21 years, 3) CMR examination within 30 days of presentation, and 4) no congenital heart disease. Clinical data and test results, including CMR findings, were abstracted from the medical record. RESULTS: For the 143 patients meeting inclusion criteria, the median age was 16.0 years (range, 0.1-20.3) and 139 (97 %) were hospitalized at the time of CMR. The median time from presentation to CMR was 2 days (0-28). The median left ventricular ejection fraction at CMR was 56 % (10-74), with 29 (20 %) below 45 %. The median right ventricular ejection fraction was 54 % (15-72), with 11 (8 %) below 40 %. There was significant variability among centers in the types of tissue characterization techniques employed (p < 0.001). Overall, late gadolinium enhancement (LGE) was used in 100 % of studies, followed by T2-weighted imaging (T2W) in 69 %, first-pass contrast perfusion (FPP) in 48 %, and early gadolinium enhancement (EGE) in 28 %. Abnormalities were most common with LGE (81 %), followed by T2W (74 %), EGE (55 %), and FPP (8 %). The CMR study was interpreted as positive for myocarditis in 117 patients (82 %), negative in 18 (13 %), and equivocal in 7 (5 %), yielding a sensitivity of 82 %. At a median follow-up of 7.1 months (0-87), all patients were alive and 5 had undergone cardiac transplantation. CMR parameters at presentation associated with persistent left ventricular dysfunction were larger left ventricular end-diastolic volume and lower left and right ventricular ejection fraction but not abnormal LGE. CONCLUSIONS: Despite significant practice variation in imaging protocol among centers, CMR had a high sensitivity for the diagnosis of myocarditis in pediatric patients. Abnormalities were most often seen with LGE followed by T2W, EGE, and FPP. These findings should be useful in designing future prospective studies.

Matrix Remodeling Promotes Pulmonary Hypertension through Feedback Mechanoactivation of the YAP/TAZ-miR-130/301 Circuit.

Pulmonary hypertension (PH) is a deadly vascular disease with enigmatic molecular origins. We found that vascular extracellular matrix (ECM) remodeling and stiffening are early and pervasive processes that promote PH. In multiple pulmonary vascular cell types, such ECM stiffening induced the microRNA-130/301 family via activation of the co-transcription factors YAP and TAZ. MicroRNA-130/301 controlled a PPAR?-APOE-LRP8 axis, promoting collagen deposition and LOX-dependent remodeling and further upregulating YAP/TAZ via a mechanoactive feedback loop. In turn, ECM remodeling controlled pulmonary vascular cell crosstalk via such mechanotransduction, modulation of secreted vasoactive effectors, and regulation of associated microRNA pathways. In vivo, pharmacologic inhibition of microRNA-130/301, APOE, or LOX activity ameliorated ECM remodeling and PH. Thus, ECM remodeling, as controlled by the YAP/TAZ-miR-130/301 feedback circuit, is an early PH trigger and offers combinatorial therapeutic targets for this devastating disease.

Baseline correction does not improve flow quantification in phase-contrast velocity measurement for routine clinical practice.

INTRODUCTION: Velocity offset errors may influence flow measurement in phase-contrast cardiovascular magnetic resonance (CMR). By using a stationary gel phantom, offset errors probably may be corrected. We tested its impact on flow measurement and, in particular, on shunt calculation in patients proven not to have any shunt. METHODS: Flow measurements were carried out in 24 patients with congenital heart disease. Baseline correction was performed by using a stationary gel phantom. RESULTS: Significantly more patients without shunts incorrectly showed a calculated shunt after baseline correction. CONCLUSIONS: Baseline correction did not improve flow measurement and was clinically not relevant for routine CMR.

Da Silva's cone repair for Ebstein's anomaly: effect on right ventricular size and function.

OBJECTIVES: Da Silva's cone repair is a novel technique for surgical reconstruction of the tricuspid valve and the right ventricle (RV) in Ebstein's anomaly. The technique consists of extensive leaflet mobilization, longitudinal plication of the atrialized ventricle and cone-shaped reconstruction of the tricuspid valve, allowing for leaflet-to-leaflet coaptation. We evaluated the influence of Da Silva's cone repair on tricuspid competency, right ventricular size and function. METHODS: From February 2010 until July 2013, 20 patients (median age 30.0 years, range 6.6-68.3 years) underwent Da Silva's cone repair. A 4- to 6-mm interatrial communication was left in all patients. Echocardiographic studies and magnetic resonance imaging (MRI) before and after the repair were evaluated. RESULTS: Median follow-up was 11 (0.5-36) months. There were 2 early deaths and no late death. Echocardiography at follow-up revealed mild or absent tricuspid regurgitation in 16 patients. Two patients showed moderate tricuspid insufficiency. MRI studies showed that the mean functional RV end-diastolic volume decreased after surgery (pre 334 [135-656] ml; post 175 [115-404] ml, P < 0.001). The mean RV ejection fraction decreased (pre 47 ± 10%; post 35 ± 13%, P = 0.001), and the mean antegrade net stroke volume of the RV increased (pre 65 ± 28 ml; post 75 ± 30 ml, P = 0.057). CONCLUSIONS: Da Silva's cone repair for Ebstein's anomaly creates excellent valve function in all patients. Consecutively, the size of the RV decreases and the antegrade net stroke volume increases 6 months after the operation.

A new strategy to identify potentially dangerous coronary arterial patterns before percutaneous pulmonary valve implantation.

Despite advances in surgical techniques, right ventricular outflow tract (RVOT) conduits are prone to fail over time. Percutaneous pulmonary valve implantation was introduced to expand the lifetime of these conduits and to decrease the number of open heart operations during a patient's lifetime. The procedure can be performed with excellent results; however, serious complications such as coronary arterial compression and conduit rupture have been reported. We present percutaneous treatment of a patient after Ross-Konno operation with RVOT conduit dysfunction and a potentially problematic course of the left anterior descending artery.

Systems-level regulation of microRNA networks by miR-130/301 promotes pulmonary hypertension.

Development of the vascular disease pulmonary hypertension (PH) involves disparate molecular pathways that span multiple cell types. MicroRNAs (miRNAs) may coordinately regulate PH progression, but the integrative functions of miRNAs in this process have been challenging to define with conventional approaches. Here, analysis of the molecular network architecture specific to PH predicted that the miR-130/301 family is a master regulator of cellular proliferation in PH via regulation of subordinate miRNA pathways with unexpected connections to one another. In validation of this model, diseased pulmonary vessels and plasma from mammalian models and human PH subjects exhibited upregulation of miR-130/301 expression. Evaluation of pulmonary arterial endothelial cells and smooth muscle cells revealed that miR-130/301 targeted PPARγ with distinct consequences. In endothelial cells, miR-130/301 modulated apelin-miR-424/503-FGF2 signaling, while in smooth muscle cells, miR-130/301 modulated STAT3-miR-204 signaling to promote PH-associated phenotypes. In murine models, induction of miR-130/301 promoted pathogenic PH-associated effects, while miR-130/301 inhibition prevented PH pathogenesis. Together, these results provide insight into the systems-level regulation of miRNA-disease gene networks in PH with broad implications for miRNA-based therapeutics in this disease. Furthermore, these findings provide critical validation for the evolving application of network theory to the discovery of the miRNA-based origins of PH and other diseases.

Improved exercise performance and quality of life after percutaneous pulmonary valve implantation.

OBJECTIVE: Percutaneous pulmonary valve implantation (PPVI) has emerged as a new approach to treat patients with dysfunctional pulmonary valve conduits. Short- and midterm results have outlined hemodynamic improvements and increase in exercise performance. However, there is a lack of knowledge about quality of life at short term follow-up. PATIENTS AND METHODS: From July 2007 to March 2013, we investigated 59 patients (17 female; median age 22.8 years) undergoing PPVI in our institution. 46 had predominant pulmonary stenosis (PS) and 13 had predominant pulmonary regurgitation (PR). They answered the quality of life questionnaire (SF-36) and underwent a cardiopulmonary exercise test and Cardiovascular Magnetic Resonance before and 6 months after PPVI. RESULTS: Peak oxygen uptake improved significantly from 27.2 (18.9; 34.0) ml/min/kg to 29.2 (22.4; 35.3) ml/min/kg (p<.0001), and from 69.6 (55.9; 83.6) %predicted to 76.3 (67.9; 92.7) %predicted, respectively. Improvements were seen in both, the PS (71.9 to 78.3 %predicted; p<.0001) and PR (62.7 to 73.0 %predicted; p<.0001) group. Self-estimated quality of life was good already before PPVI but increased in almost all domains 6 months after PPVI in PS and PR group. Significant improvements developed in "physical function", "general health perception" and "health transition" in both groups, and "physical role functioning", "vitality" and "mental health" only in the PS group. CONCLUSIONS: In patients with dysfunctional pulmonary valve conduits exercise performance and quality of life improve substantially 6months after successful percutaneous pulmonary valve implantation.

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.

L-carnitine preserves endothelial function in a lamb model of increased pulmonary blood flow.

BACKGROUND: In our model of a congenital heart defect (CHD) with increased pulmonary blood flow (PBF; shunt), we have recently shown a disruption in carnitine homeostasis, associated with mitochondrial dysfunction and decreased endothelial nitric oxide synthase (eNOS)/heat shock protein (Hsp)90 interactions that contribute to eNOS uncoupling, increased superoxide levels, and decreased bioavailable nitric oxide (NO). Therefore, we undertook this study to test the hypothesis that L-carnitine therapy would maintain mitochondrial function and NO signaling. METHODS: Thirteen fetal lambs underwent in utero placement of an aortopulmonary graft. Immediately after delivery, lambs received daily treatment with oral L-carnitine or its vehicle. RESULTS: L-Carnitine-treated lambs had decreased levels of acylcarnitine and a reduced acylcarnitine:free carnitine ratio as compared with vehicle-treated shunt lambs. These changes correlated with increased carnitine acetyl transferase (CrAT) protein and enzyme activity and decreased levels of nitrated CrAT. The lactate:pyruvate ratio was also decreased in L-carnitine-treated lambs. Hsp70 protein levels were significantly decreased, and this correlated with increases in eNOS/Hsp90 interactions, NOS activity, and NOx levels, and a significant decrease in eNOS-derived superoxide. Furthermore, acetylcholine significantly decreased left pulmonary vascular resistance only in L-carnitine-treated lambs. CONCLUSION: L-Carnitine therapy may improve the endothelial dysfunction noted in children with CHDs and has important clinical implications that warrant further investigation.

Demonstration of value of optimizing ECG triggering for cardiovascular magnetic resonance in patients with congenital heart disease.

BACKGROUND: Optimal ECG triggering is of paramount importance for correct blood flow quantification during cardiovascular magnetic resonance (CMR). However, optimal ECG triggering and therefore blood flow quantification is impaired in many patients with congenital heart disease (CHD) due to complex QRS patterns. Therefore, a new ECG-trigger algorithm was developed to address triggering problems due to complex QRS patterns.The aim of this study was to test this new ECG-trigger algorithm in routine patients with CHD and its impact on blood flow quantification. METHODS: 35 consecutive routine patients with CHD undergoing CMR were included in the study. (40% Fallot's Tetralogy, 20% aortic arch pathology, 14% transposition of the great arteries, 26% others; age 26+/-11 yrs).In all patients, blood flow in the ascending aorta was quantified using the old ECG-trigger algorithm and the new ECG-trigger algorithm in random order. Blood flow quantified using the old or new ECG-trigger algorithm was compared by Bland-Altman analysis.Three blinded investigators evaluated the vector clouds and trigger points of both ECG-trigger methods. Evaluation criteria were false positive and false negative triggered QRS complexes (specificity and sensitivity), and accuracy of detection. Accuracy of detection was defined as time scatter of the trigger around the correct trigger point. RESULTS: Specificity, sensitivity, and accuracy of detection significantly increased using the new ECG-trigger algorithm compared to the old ECG-trigger algorithm.Blood flow quantification using the old or new ECG-trigger algorithm differed more than 5% in 31% of the cases. CONCLUSIONS: Our results suggest that optimizing ECG triggering during CMR using our new algorithm can avoid errors of >5% in approximately 1/3 of routine patients with congenital heart disease (CHD). We furthermore suggest that incorrect ECG triggering appears to be problematic for blood flow quantification of many patients with CHD undergoing routine CMR.