Imaging the right heart: the use of integrated multimodality imaging

During recent years, right ventricular (RV) structure and function have been found to be an important determinant of outcome in different cardiovascular and also pulmonary diseases. Currently, echocardiography and cardiac magnetic resonance (CMR) imaging are the two imaging modalities most commonly used to visualize the RV. Most structural abnormalities of the RV can be reliably described by echocardiography but due its complex geometrical shape, echocardiographic assessment of RV function is more challenging. Newer promising echocardiographic techniques are emerging but lack of validation and limited normal reference data influence their routine clinical application. Cardiac magnetic resonance is generally considered the clinical reference technique due to its unlimited imaging planes, superior image resolution, and three-dimensional volumetric rendering. The accuracy and reliability of CMR measurements make it the ideal tool for serial examinations of RV function. Multidetector computed tomography (MDCT) plays an important role in the diagnosis of pulmonary emboli but can also be used for assessing RV ischaemic disease or as an alternative for CMR if contra-indicated. Radionuclide techniques have become more obsolete in the current era. The different imaging modalities should be considered complimentary and each plays a role for different indication

Contrast-enhanced magnetic resonance angiography of the great arteries in patients with congenital heart disease: an accurate tool for planning catheter-guided interventions

Background: Catheter-guided interventions are increasingly used for relief of lesions in patients with congenital heart disease. Exact anatomical imaging with measurement of the vascular structures is crucial in the planning of such interventions. This can be provided non-invasively and without radiation by contrast-enhanced MR angiography (CE-MRA). Aim: To evaluate the accuracy of the measurements of the vessels obtained by CE-MRA in comparison to those obtained by conventional X-ray angiography (XRA). Methods: Measurements of the diameters of aorta and pulmonary arteries were performed retrospectively and blinded on the CE-MRA and XRA images, in comparable locations. The limits of agreement between the two methods were calculated. Results: Twenty-one CE-MRA and XRA were performed in 20 children with congenital heart disease, median age 4years (1day-13years), weight 18kg (3.2-74kg). The time interval between CE-MRA and XRA was 2.6 ± 2.3months. A total of 98 measurements, 38 of the aorta and 60 of the pulmonary arteries were performed on the images obtained by each technique. The correlation between CE-MRA and XRA measurements was excellent, r=0.97, p < 0.0001. The mean difference between the two techniques was 0.018 ± 1.1mm; the limits of agreement −2.14 and + 2.18mm. Similar agreement was found for measures of the aorta (r=0.97, mean difference 0.20 ± 1.08mm) and of the pulmonary arteries (r=0.97, mean difference 0.048 ± 0.89mm). Conclusions: CE-MRA provides accurate quantitative anatomical information, which highly agrees with XRA data, and can therefore be used for planning catheter-guided procedure

Long-term follow-up of acute changes in coronary artery diameter caused by Kawasaki disease: risk factors for development of stenotic lesions

Objective: To investigate the long-term outcome of initially dilated/aneurysmatic coronary arteries in Kawasaki disease (KD) and to define risk factors for significant myocardial ischemia during follow-up, we retrospectively followed all pediatric patients with proven acute coronary changes due to KD in our institution. Methods and results: Since 1981, 38 children have been identified with coronary changes due to KD. The median age was 1.2years (0.1-12.8). In 37 patients therapy with intravenous immunoglobulin was initiated within 9days (1-30) after the beginning of KD. All received aspirin and three additionally received steroids. Median follow-up was 8.5years (0.5-24.8). We defined two groups: A aneurysm/ectasia of the coronary artery ≤5.0mm (n=23) and B aneurysm size >5.0mm (n=15). During follow-up, all coronary aneurysms of group A regressed to normal size, whereas in 14 patients of group B (93%) the aneurysms persisted or even increased in size. Four patients of group B developed severe coronary stenosis at the proximal and/or distal end of the aneurysm and needed an intervention (endovascular balloon dilation and stent implantation (n=2) or bypass surgery (n=2)) after a median time interval of 9.8years (1.0-15.6) after KD. They all had ECG changes preceding the intervention about 1year in advance. Maximum aneurysm size >5mm was a statistical significant predictive risk factor for myocardial ischemia. Conclusions: After KD, patients with a coronary aneurysm size >5.0mm need close follow-up assessments because of an elevated risk for the development of coronary stenotic lesions. In case of new and even unspecific ECG changes, coronary imaging modalities (angiography, MRI) have to be considered. Therapy options vary from percutaneous catheter interventions to bypass surgery and have to be selected individually for each patien

Anatomic reconstruction of recurrent aortic arch obstruction in children

Objective: Anatomical reconstruction of the aortic arch following aortic arch surgery is challenging. The placement of an extra-anatomical aortic bypass has been proposed for these difficult cases. This approach is not ideal in children due to possible long-term complications. This study presents the results of our policy to reconstruct the aortic arch in recurrent obstruction in children, which are not amenable to balloon dilatation. Methods: Seven children with a median age of 8 years (range 1 month-15 years) were operated for aortic arch obstruction following correction of an aortic coarctation. Six children presented another intra-cardial lesion (2 subaortic membranes; 2 VSDs, 1 ostium stenosis of the left main coronary artery, and 1 mitral valve insufficiency). The surgical approach involved a sternotomy, cardiopulmonary support using two arterial inflow cannulas (one above and one below the aortic arch), and moderate hypothermia. Enlargement of the aortic arch was performed by a sliding plasty in four patients and by a patch plasty in three patients. Associated cardiac defects were corrected as well. Results: It was technically possible to perform the planned operation in all patients. All patients survived and none presented significant postoperative complications. There were no residual gradients in six patients and a gradient of 10 mmHg in one patient postoperatively. One patient showed transient recurrent nerve palsy which recovered within 6 weeks. Follow-up echocardiographic and MRI studies revealed a normal appearing aortic arch with laminar flow. Conclusions: Although more demanding, an anatomical reconstruction of the aortic arch can be performed in infants and children with recurrent obstruction of the aortic arch with excellent initial results. This approach may prove superior to an extra-anatomic bypass in the long-ter

Geometry and dimensions of the pulmonary artery bifurcation in children and adolescents: assessment in vivo by contrast-enhanced MR-angiography

We sought to establish normal values for the diameters of the main (MPA), right (RPA), and left (LPA) pulmonary arteries and for the angles describing the geometry of the pulmonary artery bifurcation in children by using contrast-enhanced magnetic resonance angiography (CE-MRA). CE-MRA was performed in 69 children without cardiovascular disease. The median age was 10±4.9years (range 2-20), weight 37.4±18.5kg (10-82), body surface area (BSA) 1.18±0.4m2 (0.48-2.07). The pulmonary artery diameters and angles were measured at standardized sites and projections. Regression analysis of diameters and angles in relation to BSA demonstrated linear relationship between the cross-sectional diameters of the pulmonary arteries and the square root of BSA (BSA0.5). Normalized mean diameters were for the MPA 17.6±5.1mm/m2, origin of RPA 13.1±2.9mm/m2, origin of LPA 14.2±2.9mm/m2. The MPA showed a mean antero-posterior inclination of 33°±8° and a lateral leftward angulation of 18°±5°. The mean angle of the bifurcation was 99.5°±10.3°. Both side branches showed a supero-inferior course of the proximal segments, steeper for the RPA (7.7°±6.5°) than for the LPA (2.1°±7.8°). Normative curves in relation to BSA are presented for all measurements. This study provides normative values by CE-MRA for the main pulmonary artery and its side branches in children during somatic growth. These data can be used for identifying pulmonary arteries anomalies in children, and evaluate the need and the modality for treatmen

Outcome of Biventricular Repair in Infants With Multiple Left Heart Obstructive Lesions

The decision to perform biventricular repair for infants with multiple obstructive or hypoplastic left heart lesions (LHL) and borderline left ventricle (LV) may be controversial. This study sought to assess the mortality and morbidity of patients with LHL after biventricular repair and to determine the growth of the left-sided cardiac structures. Retrospective analysis of 39 consecutive infants with LHL who underwent biventricular repair was performed. The median age at surgery was 7days (range 1-225days), and the median follow-up period was 34months (range 1-177months). Between diagnosis and the end of the follow-up period, the size of the aortic annulus (z-score −4.1±2.8 vs. −0.1±2.7) and the LV (LV end-diastolic diameter z-score −1.7±2.8 vs. 0.21±1.7) normalized. During the follow-up period, 23 patients required 39 reinterventions (62%) consisting of redo surgery for 21 patients (57%) and catheter-guided reinterventions for 8 patients (22%). At the end of the follow-up period, 25 of 34 patients were doing subjectively well; 10 children (29%) received cardiac medication; 12 (35%) presented with failure to thrive (weight ≤ P3) and 5 (15%) with pulmonary hypertension. The overall mortality rate was 13%. Biventricular repair for patients with multiple LHL results in sufficient growth of the left-sided cardiac structures. Nevertheless, residual or newly developing obstructive lesions and pulmonary hypertension are frequent, causing significant morbidity that requires reinterventio