First-in-Human Closed-Chest Transcatheter Superior Cavopulmonary Anastomosis

Interventional cardiovascular magnetic resonance: state-of-the-art

Transcatheter cardiovascular interventions increasingly rely on advanced imaging. X-ray fluoroscopy provides excellent visualization of catheters and devices, but poor visualization of anatomy. In contrast, magnetic resonance imaging (MRI) provides excellent visualization of anatomy and can generate real-time imaging with frame rates similar to X-ray fluoroscopy. Realization of MRI as a primary imaging modality for cardiovascular interventions has been slow, largely because existing guidewires, catheters and other devices create imaging artifacts and can heat dangerously. Nonetheless, numerous clinical centers have started interventional cardiovascular magnetic resonance (iCMR) programs for invasive hemodynamic studies or electrophysiology procedures to leverage the clear advantages of MRI tissue characterization, to quantify cardiac chamber function and flow, and to avoid ionizing radiation exposure. Clinical implementation of more complex cardiovascular interventions has been challenging because catheters and other tools require re-engineering for safety and conspicuity in the iCMR environment. However, recent innovations in scanner and interventional device technology, in particular availability of high performance low-field MRI scanners could be the inflection point, enabling a new generation of iCMR procedures. In this review we review these technical considerations, summarize contemporary clinical iCMR experience, and consider potential future applications.

Transcatheter Electrosurgery: A Narrative Review

Transcatheter electrosurgery describes the ability to cut and traverse tissue, at a distance, without an open surgical field and is possible using either purpose-built or off-the-shelf devices. Tissue traversal requires focused delivery of radiofrequency energy to a guidewire tip. Initially employed to cross atretic pulmonary valves, tissue traversal has enabled transcaval aortic access, recanalization of arterial and venous occlusions, transseptal access, and many other techniques. To cut tissue, the selectively denuded inner curvature of a kinked guidewire (the Flying-V) or a single-loop snare is energized during traction. Adjunctive techniques may complement or enable contemporary transcatheter procedures, whereas myocardial slicing or excision of ectopic masses may offer definitive therapy. In this contemporary review we discuss the principles of transcatheter electrosurgery, and through exemplary clinical applications highlight the range of therapeutic options offered by this versatile family of procedures.

Transcatheter Hepatic Conduit-Azygous Vein Connection Reduces Pulmonary Arteriovenous Malformations in a Cyanotic Fontan Patient

The authors report a closed-chest, transcatheter large-vessel connection (hepatic conduit to azygous vein) to reverse pulmonary arteriovenous malformations in a 10-year-old patient after Fontan for heterotaxy/interrupted inferior vena cava, with an increase in oxygen saturation from 78% to 96%. Computational fluid dynamics estimated a 14-fold increase in hepatic blood flow to the left pulmonary artery (from 1.3% to 14%). (Level of Difficulty: Advanced.).

Transcatheter implantation of covered stents serving as extravascular conduits-Proof of a CT-based approach in three cases

BACKGROUND

Covered stents perform similar to surgically implanted conduits, although the stents work inside of vessels. We present a computed tomography (CT)-based workflow for the implantation of covered stents as extravascular conduits.

METHODS

We selected three different use cases: 1. Connecting a left-sided partially anomalous drainage of a pulmonary vein to the left atrium. 2. Bypassing an outgrown Dacron conduit in aortic recoarctation. 3. Re-directing hepatic venous blood to the left lung in a Fontan patient with heterotaxy, connecting the innominate vein to the right pulmonary artery like a right-sided cavopulmonary connection. By postprocessing and analyzing CT scans for planning and by the use of long needles under biplane fluoroscopy for the realization of the procedure, we projected and performed the exit of a long needle out of a vessel, the re-entering of a target vessel, and the bridging of the extravascular distance by implantation of covered stents.

RESULTS

In all three cases, the covered stents were placed successfully, connecting vessels of 15-50 mm distance from each other with very good hemodynamic results. In one case, two stents were placed consecutively, overlapping each other to accomplish an exact fitting at the connection sites to the native vessels.

Percutaneous mitral valve repair in adults with congenital heart disease: Report of the first case-series

BACKGROUND

Systemic atrioventricular valve regurgitation (AVVR) is frequently encountered in adults with congenital heart disease (CHD). Surgical intervention is the mainstay of therapy, but in a specific high-risk subset, percutaneous valve repair might offer a lower-risk alternative.

METHODS

Three patients with complex CHD and severe symptomatic AVVR underwent percutaneous mitral valve repair at a single center. All were deemed to be high-risk for surgery by a multidisciplinary CHD team and provided informed consent for the compassionate use of the MitraClip (Abbott, Santa Clara, CA). Three-dimensional heart models were generated for the procedure, which was performed by an adult CHD cardiologist (who provided imaging support) and an interventional cardiologist with expertise in CHD and percutaneous mitral valve repair.

RESULTS

The first case was a 39 year-old-woman with [S,L,D] dextrocardia, double outlet right ventricle, mild tricuspid hypoplasia, and a secundum atrial septal defect, who was palliated at age 35 with a right bidirectional Glenn and later developed severe, symptomatic mitral regurgitation, and underwent placement of one MitraClip XT_R device. Two patients with L-loop transposition of the great arteries each successfully underwent placement of two MitraClip XT_R devices; one patient had a single-leaflet detachment of one of the clips with no change in regurgitation or clip position on follow-up. All patients had significant reduction of AVVR and improvement in NYHA functional class.

CONCLUSIONS

Percutaneous atrioventricular valve repair in adults with CHD is feasible with the MitraClip but requires significant preprocedural planning and a multidisciplinary team that combines CHD and interventional therapeutic expertise.

Purpose-built transcatheter cavopulmonary anastomosis device requirements: Multi-modality imaging evaluation

BACKGROUND/PURPOSE

Patients with a functional single ventricle undergo multiple, palliative open-heart surgeries. This includes a superior cavopulmonary anastomosis or bidirectional Glenn shunt. A less-invasive transcatheter approach may reduce morbidity.

METHODS/MATERIALS

We analyzed pre-Glenn X-ray contrast angiography (XA), cardiac computed tomography (CT), and cardiac magnetic resonance (CMR) studies.

RESULTS

Over an eleven-year period (1/2007 - 6/2017), 139 Glenn surgeries were performed at our institution. The typical age range at surgery was 59 - 371 days (median = 163; IQR = 138 - 203). Eight-nine XA, ten CT, and ten CMR studies obtained from these patients were analyzed. Cephalad SVC measurements (millimeters) were 7.3 ± 1.7 (XA), 7.7 ± 1.6 (CT) and 6.9 ± 1.8 (CMR). RPA measurements were 7.3 ± 1.9 (XA), 7.4 ± 1.6 (CT) and 6.6 ± 1.9 (CMR). Potential device lengths were 10.9 ± 6 - 17.4 ± 6.4 (XA), 10.1 ± 2.1 - 17.7 ± 2.4 (CT) and 17.3 ± 4. - 23.7 ± 5.5 (CMR). SVC-RPA angle (degrees) was 132.9 ± 13.2 (CT) and 140 ± 10.2 (MRI). Image quality of all CT (100%), almost all XA (SVC 100%, RPA 99%), and most MRI (SVC 80%, RPA 90%) were deemed sufficient. Parametric modeling virtual fit device with 10 mm diameter and 20 - 25 mm length was ideal.

CONCLUSIONS

Ideal transcatheter cavopulmonary shunt device for the typical patient would be 10 mm in diameter and 20-25 mm in length.

Transcatheter biventricular conversion in an adult patient with a 1.5 ventricle Glenn palliation and superior vena cava syndrome

Covered stents have a continually expanding spectrum of applications for patients with congenital heart disease. Here we report use of covered stents to successfully perform a first-in-human percutaneous biventricular conversion of a 1.5 ventricle Glenn palliation in an adult born with pulmonary atresia. This case demonstrates that in patients considered borderline for biventricular repair, surgery can potentially be modified to promote growth of underdeveloped structures and setup for transcatheter biventricular conversion.

Transcatheter creation of bidirectional cavopulmonary connections by needle punctures in two patients

We report on two patients who received a transcatheter cavopulmonary connection by a needle puncture under deep conscious sedation. In both patients, the vessel-to-vessel connection was achieved by a venous access into the superior caval vein and direct needle puncture of the pulmonary artery. The two cavopulmonary anastomoses were held open by a covered stent and a bare-metal stent, respectively.

Transcatheter Electrosurgery: JACC State-of-the-Art Review

Transcatheter electrosurgery refers to a family of procedures using radiofrequency energy to vaporize and traverse or lacerate tissue despite flowing blood. The authors review theory, simulations, and benchtop demonstrations of how guidewires, insulation, adjunctive catheters, and dielectric medium interact. For tissue traversal, all but the tip of traversing guidewires is insulated to concentrate current. For leaflet laceration, the "Flying V" configuration concentrates current at the inner lacerating surface of a kinked guidewire. Flooding the field with non-ionic dextrose eliminates alternative current paths. Clinical applications include traversing occlusions (pulmonary atresia, arterial and venous occlusion, and iatrogenic graft occlusion), traversing tissue planes (atrial and ventricular septal puncture, radiofrequency valve repair, transcaval access, Potts and Glenn shunts), and leaflet laceration (BASILICA, LAMPOON, ELASTA-Clip, and others). Tips are provided for optimizing these techniques. Transcatheter electrosurgery already enables a range of novel therapeutic procedures for structural heart disease, and represents a promising advance toward transcatheter surgery.

MRI Catheterization: Ready for Broad Adoption

In recent years, interventional cardiac magnetic resonance imaging (iCMR) has evolved from attractive theory to clinical routine at several centers. Real-time cardiac magnetic resonance imaging (CMR fluoroscopy) adds value by combining soft-tissue visualization, concurrent hemodynamic measurement, and freedom from radiation. Clinical iCMR applications are expanding because of advances in catheter devices and imaging. In the near future, iCMR promises novel procedures otherwise unsafe under standalone X-Ray guidance.

X-ray fused with MRI guidance of pre-selected transcatheter congenital heart disease interventions

OBJECTIVES

To determine whether X-ray fused with MRI (XFM) is beneficial for select transcatheter congenital heart disease interventions.

BACKGROUND

Complex transcatheter interventions often require three-dimensional (3D) soft tissue imaging guidance. Fusion imaging with live X-ray fluoroscopy can potentially improve and simplify procedures.

METHODS

Patients referred for select congenital heart disease interventions were prospectively enrolled. Cardiac MRI data was overlaid on live fluoroscopy for procedural guidance. Likert scale operator assessments of value were recorded. Fluoroscopy time, radiation exposure, contrast dose, and procedure time were compared to matched cases from our institutional experience.

RESULTS

Forty-six patients were enrolled. Pre-catheterization, same day cardiac MRI findings indicated intervention should be deferred in nine patients. XFM-guided cardiac catheterization was performed in 37 (median age 8.7 years [0.5-63 years]; median weight 28 kg [5.6-110 kg]) with the following prespecified indications: pulmonary artery (PA) stenosis (n = 13), aortic coarctation (n = 12), conduit stenosis/insufficiency (n = 9), and ventricular septal defect (n = 3). Diagnostic catheterization showed intervention was not indicated in 12 additional cases. XFM-guided intervention was performed in the remaining 25. Fluoroscopy time was shorter for XFM-guided intervention cases compared to matched controls. There was no significant difference in radiation dose area product, contrast volume, or procedure time. Operator Likert scores indicated XFM provided useful soft tissue guidance in all cases and was never misleading.

CONCLUSIONS

XFM provides operators with meaningful three-dimensional soft tissue data and reduces fluoroscopy time in select congenital heart disease interventions.