Transcatheter Interventions in Adult Congenital Heart Disease.

Congenital heart disease (CHD) is the most common congenital birth defect with an incidence of 1 in 100. Current survival to adulthood is expected in 9 out of 10 children with severe CHD as the diagnostic, interventional, and surgical success improves. The adult CHD (ACHD) population is increasingly diverse, reflecting the broad spectrum of CHD and evolution of surgical techniques to improve survival. Similarly, transcatheter interventions have seen exponential growth and creativity to reduce the need for repeat sternotomies. This article focuses on newer data and evolving techniques for transcatheter interventions specific to certain ACHD populations.

Hybrid approach for harmony transcatheter pulmonary valve replacement.

The Harmony™ Transcatheter Pulmonary Valve (Medtronic) was recently approved by the Food and Drug Administration for transcatheter pulmonary valve replacement in native right ventricular outflow tracts. Despite this milestone, some patients have main pulmonary arteries that are severely dilated and continue to require surgical pulmonary valve replacement. The hybrid approach combines surgical creation of a landing zone, transcatheter valve deployment, and suture stabilization of the implanted valve. In this case series, we report the first use of a hybrid approach for Harmony™ transcatheter pulmonary valve replacement. Two cases are reported with varying approaches for surgical creation of a landing zone followed by successful placement of a Harmony™ valve.

Multicenter Outcomes of Catheter Ablation for Atrioventricular Reciprocating Tachycardia Mediated by Twin Atrioventricular Nodes.

OBJECTIVES: This study sought to describe the electrophysiologic properties and catheter ablation outcomes for atrioventricular reciprocating tacchycardia via twin atrioventricular nodes (T-AVRT). BACKGROUND: Although catheter ablation for T-AVRT is an established entity, there are few data on the electrophysiological properties and outcomes of this procedure. METHODS: An international, multicenter study was conducted to collect retrospective procedural and outcomes data for catheter ablation of T-AVRT. RESULTS: Fifty-nine patients with T-AVRT were identified (median age at procedure, 8 years [interquartile range: 4.4-17.0 years]; 49% male). Of these, 55 (93%) were diagnosed with heterotaxy syndrome (right atrial isomerism in 39, left atrial isomerism in 8, and indeterminate in 8). Twenty-three (39%) had undergone Fontan operation (12 extracardiac, 11 lateral tunnel). After the Fontan operation, atrial access was conduit or baffle puncture in 15 (65%), fenestration in 5 (22%), and retrograde in 3 (13%). Acute success was achieved in 43 (91%) of 47 attempts (targeting an anterior node in 23 and posterior node in 24). There was no high-grade AV block or change in QRS duration. Over a median of 3.8 years, there were 3 recurrences. Of 7 patients with failed index procedure or recurrent T-AVRT, 6 (86%) were associated with anatomical hurdles such as prior Fontan or catheter course through an interrupted inferior vena cava-to-azygous vein continuation (P = 0.11). CONCLUSIONS: T-AVRT can be targeted successfully with low risk for recurrence. Complications were rare in this population. Anatomical challenges were common among patients with reduced short and long-term efficacy, representing opportunities for improvement in procedural timing and planning.

Successful radiofrequency perforation and balloon decompression of cor triatriatum sinister using novel technique, a case series.

Cor triatriatum sinister (CTS) is a rare congenital cardiac anomaly representing <0.1% of all congenital cardiac malformations. It is characterized by the presence of a left atrial (LA) membrane that leads to left ventricular inflow obstruction. Uncorrected, obstructed CTS may have significant sequelae such as pulmonary hypertension or arrhythmias. Transcatheter balloon decompression has been described as a successful alternative to surgical resection of the obstructing membrane. Our review of the literature revealed no reported cases utilizing radiofrequency (RF) energy to perforate the CTS membrane prior to balloon decompression. This manuscript describes two patients with CTS who were treated successfully with a transcatheter technique using RF energy to perforate the obstructing membrane prior to balloon angioplasty and decompression of the LA.

Mechanical properties of low-diameter balloon expandable covered stents.

OBJECTIVES: To determine over-dilation potential of commercially available covered stents. BACKGROUND: Covered stents including the Atrium iCast, Gore VBX, and Lifestream stents (LS) can treat ruptures, dissections, and aneurysms in small vessels. Especially in growing patients, stents often require serial dilations beyond their implant or nominal diameters. Tolerance of serial dilations is clinically important information for interventionalists. METHODS: Serial dilations of 5-12 mm iCast, VBX, and LS covered stents were performed in 1-2 mm increments (up to 20 mm). With each dilation, foreshortening and recoil were measured, and stent strut and covering integrity were assessed. High-pressure balloons were used to expand the stents until they fractured or could not be further expanded. RESULTS: The 5-8 mm LS tolerated dilation to 14.5-16 mm. The 10-12 mm LS stents tolerated dilation to 18 mm and fractured on the 20 mm balloon. LS stents foreshortened 35%-45% on average after 8 mm of over-dilation and had 5%-10% recoil on <6 mm over-dilation. All iCast stents tolerated dilation to 12-13 mm and required fracture for dilation to >14 mm. ICast stents foreshortened 19%-29% at maximum dilation, with 3-6% recoil on <2 mm over-dilation, and < 3% thereafter. VBX stents over-dilated to 2.9-4.7 mm above nominal, foreshortening 40%-50% after 4-6 mm of over-dilation before collapsing into a ring. VBX stent recoil was <2.5% on all dilations. CONCLUSIONS: LS stents had the greatest over-dilation potential. VBX stents had the least recoil but tended to foreshorten significantly 3-4 mm above nominal. Regardless of nominal size, all iCast stents (including the 5 mm) tolerated dilation to a maximum of 12-13 mm.

The Potential Impact and Timeline of Engineering on Congenital Interventions.

Congenital interventional cardiology has seen rapid growth in recent decades due to the expansion of available medical devices. Percutaneous interventions have become standard of care for many common congenital conditions. Unfortunately, patients with congenital heart disease often require multiple interventions throughout their lifespan. The availability of transcatheter devices that are biodegradable, biocompatible, durable, scalable, and can be delivered in the smallest sized patients will rely on continued advances in engineering. The development pipeline for these devices will require contributions of many individuals in academia and industry including experts in material science and tissue engineering. Advances in tissue engineering, bioresorbable technology, and even new nanotechnologies and nitinol fabrication techniques which may have an impact on the field of transcatheter congenital device in the next decade are summarized in this review. This review highlights recent advances in the engineering of transcatheter-based therapies and discusses future opportunities for engineering of transcatheter devices.

Clinical and electrophysiological properties of atrial tachycardia after pediatric heart transplantation.

BACKGROUND: Pediatric heart transplant recipients are at an elevated risk for development of atrial tachycardia (AT); however, the underlying mechanisms and long-term outcomes are unclear. OBJECTIVE: We hypothesized that occurrence of AT in pediatric heart transplant recipients would be associated with a higher frequency of adverse events during follow-up. METHODS: A single-center retrospective review of all pediatric heart transplant recipients with suspected AT between 1997 and 2017 was performed. Unaffected controls were matched with cases for age and transplant era. Clinical characteristics and long-term outcomes were compared between groups. RESULTS: Of 294 heart transplant recipients, 13 with AT at electrophysiology study (4.4%) were identified and compared with 29 controls. The most common mechanism was focal (11), followed by atrial flutter (two), and electrical reconnection of a surgical atrial anastomosis (two). Focal AT was only observed in the right atrium or atrial septum, and was frequently found on or near the crista terminalis. Relative to controls, cases exhibited more frequent clinical evidence of rejection (9/13 vs 10/29, P  =  0.037). For patients with AT, there was a higher rate of death/retransplant among cases (log-rank P  =  0.022), which remained significant in multivariate analysis. CONCLUSION: In this cohort, the most common form of AT after pediatric heart transplantation was focal, with predilection for sites near the crista terminalis. Transplant patients with AT experienced a higher rate of clinical rejection and the composite end-point of retransplantation or death relative to unaffected controls.