Validation of aortic valve 4D flow analysis and myocardial deformation by cardiovascular magnetic resonance in patients after the arterial switch operation.

BACKGROUND: Aortic regurgitation (AR) and subclinical left ventricular (LV) dysfunction expressed by myocardial deformation imaging are common in patients with transposition of the great arteries after the arterial switch operation (ASO). Echocardiographic evaluation is often hampered by reduced acoustic window settings. Cardiovascular magnetic resonance (CMR) imaging provides a robust alternative as it allows for comprehensive assessment of degree of AR and LV function. The purpose of this study is to validate CMR based 4-dimensional flow quantification (4D flow) for degree of AR and feature tracking strain measurements for LV deformation assessment in ASO patients. METHODS: A total of 81 ASO patients (median 20.6 years, IQR 13.5-28.4) underwent CMR for 4D and 2D flow analysis. CMR global longitudinal strain (GLS) feature tracking was compared to echocardiographic (echo) speckle tracking. Agreements between and within tests were expressed as intra-class correlation coefficients (ICC). RESULTS: Eleven ASO patients (13.6%) showed AR > 5% by 4D flow, with good correlation to 2D flow assessment (ICC = 0.85). 4D flow stroke volume of the aortic valve demonstrated good agreement to 2D stroke volume over the mitral valve (internal validation, ICC = 0.85) and multi-slice planimetric LV stroke volume (external validation, ICC = 0.95). 2D flow stroke volume showed slightly less, though still good agreement with 4D flow (ICC = 0.78) and planimetric LV stroke volume (ICC = 0.87). GLS by CMR was normal (- 18.8 ± 4.4%) and demonstrated good agreement with GLS and segmental analysis by echocardiographic speckle tracking (GLS = - 17.3 ± 3.1%, ICC of 0.80). CONCLUSIONS: Aortic 4D flow and CMR feature tracking GLS analysis demonstrate good to excellent agreement with 2D flow assessment and echocardiographic speckle tracking, respectively, and can therefore reliably be used for an integrated and comprehensive CMR analysis of aortic valve competence and LV deformation analysis in ASO patients.

Predictors and Outcome of Pericardial Effusion After Hematopoietic Stem Cell Transplantation in Children.

Pericardial Effusion (PE) is a potentially life-threatening complication of Hematopoietic Cell Transplantation (HCT). Our study aim was to identify incidence, risk factors, response to treatment, and outcome of PE after pediatric HCT. All patients after HCT at our tertiary center between 2005 and 2010 were included. Endpoints were PE development and overall survival. We analyzed patient factors, HCT details, and complications and used Cox proportional hazard regression modeling to identify predictors for PE. Twelve out of 129 patients (9.3%) developed PE. Multivariate analysis demonstrated that young age at HCT was a predictor for PE: expressed per year increase in age HR = 0.66 (95% CI 0.46-0.95, p = 0.03). PE had no impact on overall mortality of HCT. Mild respiratory symptoms and vomiting were presenting symptoms for PE. Discontinuation of calcineurin inhibitors-with or without pericardiocentesis-was the only effective treatment for PE, in contrast to diuretics or increased immunosuppression. Seven of 12 PE patients had pericardiocentesis, which was safe and effective in all. Pericardial effusion is not rare after HCT, and young age is the only significant risk factor. Calcineurin inhibitor toxicity appears to be the primary cause of PE after HCT, and discontinuation is effective in the reduction of PE. Pericardiocentesis for PE is a safe and effective procedure. Pericardial effusion did not have an impact on survival after HCT.

Aortic elasticity and size are associated with aortic regurgitation and left ventricular dysfunction in tetralogy of Fallot after pulmonary valve replacement.

BACKGROUND: Aortic wall pathology and concomitant aortic dilatation have been described in tetralogy of Fallot (TOF) patients, which may negatively affect aortic valve and left ventricular systolic function. OBJECTIVE: To assess aortic dimensions, aortic elasticity, aortic valve competence and biventricular function in repaired TOF patients after pulmonary valve replacement (PVR) using magnetic resonance imaging (MRI). METHODS: MRI was performed in 16 patients with TOF after PVR (10 male; mean age 31 years (SD 15)) and 16 age and gender-matched healthy subjects. RESULTS: TOF patients showed aortic root dilatation (mean difference 7.8-8.8 mm, p<0.01 at all four predefined levels) and reduced aortic elasticity (pulse wave velocity in aortic arch 5.5 m/s (1.2) vs 4.6 m/s (0.9), p = 0.04; aortic root distensibility 1.4/10(-3) mm Hg (1.7) vs 5.7/10(-3) mm Hg (3.6), p<0.01). Minor degrees of aortic regurgitation (AR) (AR fraction 6% (8) vs 1% (1), p<0.01) and reduced left ventricular ejection fraction (LVEF) were present (51% (8) vs 58% (6), p = 0.01), whereas right ventricular ejection fraction (RVEF) was within normal limits (47% (8) vs 52% (7), p = 0.06). The degree of AR fraction was associated with dilatation of the aortic root (r = 0.39-0.49, p<0.05) and reduced aortic root distensibility (r = 0.44, p = 0.02), whereas reduced LVEF was correlated with degree of AR and RVEF (r = 0.41, p = 0.02 and r = 0.49, p<0.01, respectively). CONCLUSIONS: Aortic root dilatation and reduced aortic elasticity are frequently present in patients with TOF, in addition to minor degrees of AR and reduced left ventricular systolic function. Aortic wall pathology in repaired TOF patients may therefore represent a separate mechanism leading to left ventricular dysfunction, as part of a multifactorial process of left ventricular dysfunction.

Right ventricular hypertrophy and diastolic dysfunction in arterial switch patients without pulmonary artery stenosis.

OBJECTIVE: To assess pulmonary flow dynamics and right ventricular (RV) function in patients without significant anatomical narrowing of the pulmonary arteries late after the arterial switch operation (ASO) by using magnetic resonance imaging (MRI). METHODS: 17 patients (mean (SD), 16.5 (3.6) years after ASO) and 17 matched healthy subjects were included. MRI was used to assess flow across the pulmonary trunk, RV systolic and diastolic function, and RV mass. RESULTS: Increased peak flow velocity (>1.5 m/s) was found across the pulmonary trunk in 14 of 17 patients. Increased RV mass was found in ASO patients: 14.9 (3.4) vs 10.0 (2.6) g/m2 in normal subjects (p<0.01). Delayed RV relaxation was found after ASO: mean tricuspid valve E/A peak flow velocity ratio = 1.60 (0.96) vs 1.92 (0.61) in normal subjects (p = 0.03), and E-deceleration gradients = -1.69 (0.73) vs -2.66 (0.96) (p<0.01). After ASO, RV mass correlated with pulmonary trunk peak flow velocity (r = 0.49, p<0.01) and tricuspid valve E-deceleration gradients (r = 0.35, p = 0.04). RV systolic function was well preserved in patients (ejection fraction = 53 (7)% vs 52 (8)% in normal subjects, p = 0.72). CONCLUSIONS: Increased peak flow velocity in the pulmonary trunk was often observed late after ASO, even in the absence of significant pulmonary artery stenosis. Haemodynamic consequences were RV hypertrophy and RV relaxation abnormalities as early markers of disease, while systolic RV function was well preserved.