Philippe Acar

Cardiac imaging of congenital heart diseases during interventional procedures continues to evolve: Pros and cons of the main techniques

Cardiac catheterization has contributed to the progress made in the management of patients with congenital heart disease (CHD). First, it allowed clarification of the diagnostic assessment of CHD, by offering a better understanding of normal cardiac physiology and the pathophysiology and anatomy of complex malformations. Then, it became an alternative to surgery and a major component of the therapeutic approach for some CHD lesions. Nowadays, techniques have evolved and cardiac catheterization is widely used to percutaneously close intracardiac shunts, to relieve obstructive valvar or vessel lesions, and for transcatheter valve replacement. Accurate imaging is mandatory to guide these procedures. Cardiac imaging during catheterization of CHD must provide accurate images of lesions, surrounding cardiac structures, medical devices and tools used to deliver them. Cardiac imaging has to be real-time with an excellent temporal resolution to ensure eyes-hands synchronization and device-target area accurate positioning. In this comprehensive review, we provide an overview of conventional cardiac imaging tools used in the catheterization laboratory in daily practice, as well as the effect of recent evolution and future imaging modalities.

Stents in paediatric and adult congenital interventional cardiac catheterization

A stent is a tubular meshed endoprosthesis that has contributed to the development of interventional catheterization over the past 30 years. In congenital heart diseases, stents have offered new solutions to the treatment of congenital vessel stenosis or postsurgical lesions, to maintain or close shunt patency, and to allow transcatheter valve replacement. First, stents were made of bare metal. Then, stent frameworks evolved to achieve a better compromise between radial strength and flexibility. However, almost all stents used currently in children have not been approved for vascular lesions in children and are therefore used off-label. Furthermore, the inability of stents to follow natural vessel growth still limits their use in low-weight children and infants. Recently, bioresorbable stents have been manufactured and may overcome this issue; they are made from materials that may dissolve or be absorbed in the body. In this review, we aim to describe the history of stent development, the technical characteristics of stents used currently, the clinical applications and results, and the latest technological developments and perspectives in paediatric and adult congenital cardiac catheterization.

Stenting in paediatric and adult congenital heart diseases: A French multicentre study in the current era

BACKGROUNDnMany stents are used off-label during the management of congenital heart diseases (CHD).nnnAIMSnTo describe indications for, results of, and adverse events associated with stenting in CHD in current practice.nnnMETHODSnParticipation in this study was proposed to all catheterization laboratories that specialize in CHD in France (M3C network). All paediatric and adult CHD cases with stent implantation in 2013 were included retrospectively.nnnRESULTSnOverall, 207 stents were implanted in 151 patients across 11 centres. Median age was 13.7 years (range, 5 days to 70.1 years). Main procedure indications were branch pulmonary artery angioplasty (n=46, 29.1%), aortic (re)coarctation stenting (n=43, 27.2%), percutaneous pulmonary valve implantation (n=32, 20.2%) and ductus arteriosus stenting (n=14, 8.9%). The main stents implanted were the CP Stent™ (n=61, 29.5%), the Max™ LD stent (n=43, 20.8%), the Valeo(®) stent (n=28, 13.5%) and valved stents (n=30, 14.5%). Procedures were considered successful in 96.8% of cases (95% confidence interval [CI] 92.8-99.0%). Adverse events were observed in 23 procedures (14.7%, 95% CI 9.5-21.0%). Ductus arteriosus stenting (odds ratio 12.4, 95% CI 2.0-77.5; P<0.01) and pulmonary revalvulation (odds ratio 5.9, 95% CI 1.1-32.3; P=0.04) were risk markers for stent-related adverse events.nnnCONCLUSIONSnStents are used in various CHD catheterization procedures, from infancy to adult age. The adverse events rate is significant and is related to the type of procedure.

Feasibility, Safety and Accuracy of Echocardiography-Fluoroscopy Imaging Fusion During Percutaneous Atrial Septal Defect Closure in Children

Background: Imaging fusion between echocardiography and fluoroscopy was recently developed. The aim of this study was to assess its feasibility and accuracy during pediatric cardiac catheterization. Methods: Thirty‐one patients (median weight, 26 kg; interquartile range [IQR], 21–37 kg) who underwent percutaneous atrial septal defect closure were prospectively included. The feasibility and accuracy of various imaging fusion modalities (live two‐dimensional, live color two‐dimensional, live three‐dimensional and markers) with EchoNavigator software were assessed. To assess the accuracy of spatial registration of the echocardiogram on the fluoroscopic image, the occluder screw, an object that appeared on each image, was used as a reference tool, and the distance between the two when fused was measured. A distance was measured on the fusion screen between a marker positioned on the screw from the echocardiography screen and from the fluoroscopy screen (distance 1). Another distance was measured on the fusion screen between the screw visualized by three‐dimensional echocardiography and by fluoroscopy (distance 2). The two distances were measured on four C‐arm orientations in end‐systolic and end‐diastolic frames. Results: Fusion and marker positioning were feasible in real time in all cases. On the fusion screen, median systolic and diastolic distance 1 were 0.5 mm (IQR, 0.3–1 mm) and 2 mm (IQR, 1.5–2.5 mm; P < .0001), respectively. The marker positioned from the echocardiography screen was fixed on the fusion screen and did not follow the movement of the screw. Median systolic and diastolic distance 2 were 0.5 mm (IQR, 0–0.5 mm) and 2 mm (IQR, 1.5–2.5 mm; P < .0001), respectively. Conclusions: Echocardiographic fluoroscopic imaging fusion is feasible, safe, and accurate in children weighting >20 kg. This technique offers a new method of imaging guidance in the catheterization laboratory for complex procedures and training. HIGHLIGHTSEchocardiography‐fluoroscopy imaging fusion is feasible, safe and accurate in children.Echocardiography‐fluoroscopy imaging fusion is displayed in real time.Echocardiography‐fluoroscopy imaging fusion may be beneficial for training.

Usefulness of echocardiographic-fluoroscopic fusion imaging in children with congenital heart disease

BACKGROUNDnTransoesophageal echocardiography (TOE) has become indispensable in the catheterization laboratory in the guidance of some percutaneous interventions, as a complementary imaging technique to fluoroscopy. However, the two imaging modalities are presented separately and differently, making interpretation of the anatomical spatial relationships complicated. EchoNavigator® (Philips Healthcare, Best, the Netherlands) is an innovative software package, enabling fusion of fluoroscopic and echocardiographic images on the same screen.nnnAIMSnTo assess the feasibility of EchoNavigator® in the guidance of interventional procedures, and to present our initial clinical experience with this software.nnnMETHODSnChildren with congenital heart disease who underwent interventional catheterization needing guidance with TOE from December 2015 to December 2017 were included. TOE was realized using a X7-2t TOE probe (Philips Healthcare) connected to an echocardiographic system (EPIC™; Philips Healthcare, Andover, MA). Fluoroscopy was realized using the Allura Xper FD/10 system (Philips Healthcare). Image fusion was attempted in all patients using EchoNavigator®. Markers were positioned on the target zone on echocardiographic images, and projected onto the merged screen.nnnRESULTSnFifty-one children were included (mean age, 8 years; mean weight, 25kg). Thirty-six patients underwent atrial septal defect closure, 10 ventricular septal defect closure, three aortic valve dilatation and two right ventricular outflow tract revalvulation. Image fusion was successfully obtained in all patients during all steps of the procedure. No complication related to the TOE probe was observed. Markers were successfully positioned in the all target zones, and were automatically projected onto the fusion screen.nnnCONCLUSIONSnThe EchoNavigator® system is feasible and safe in the guidance of interventional catheterization in children with congenital heart disease; it enables better appreciation of anatomical relationships and improves the confidence of the interventionist.