Congenital Heart Interventions

Extravascular protrusion of the Alterra adaptive prestent identified on surveillance computed tomography imaging. Gillespie MJ, Maschietto N, Aboulhosn JA, Balzer DT, Qureshi AM, McElhinney DB. Catheter Cardiovasc Interv. 2024 Aug;104(2):256-263. doi: 10.1002/ccd.31147. Epub 2024 Jul 5.PMID: 38967206 Take Home Points Cardiovascular perforation by the Alterra pre-stent is an observed phenomenon that can be detected incidentally on post-procedure CT imaging In the patients presented, no clinical complications occurred from the Alterra perforation, though the potential to become clinically significant remains The pre-stent perforated the main PA in all 6 patients and in 1 patient there was also perforation of the subvalvar RVOT Commentary from Dr. Jonathon Hagel (C.S. Mott Children’s Hospital, University of Michigan) Patients with patched or native right ventricular outflow tracts (RVOTs) that are too large for traditional balloon expandable pulmonary valves are now often treated with a self-expanding platform. The Alterra adaptive pre-stent is a transcatheter self-expanding device that provides a landing zone for a balloon expandable 29 mm Sapien 3 valve implant. The authors of this study reported selected cases of the Alterra-Sapien implant form 6 institutions to document the phenomenon and provide considerations for potential procedural and patient characteristics in such cases. Each institution provided one patient with a perforation of the Alterra pre-stent that was incidentally discovered on a CT scan performed one day to 21 months after implant. The age range of patients included in this descriptive case series was 16-50 years. Three patients had a history of Tetralogy of Fallot, two had valvar pulmonary stenosis (PS) and one had pulmonary atresia with an intact ventricular septum. One of the valvar PS patients underwent balloon valvuloplasty only and had no history of surgical RVOT intervention. All procedures were acutely successful without significant compilations. In all patients there was perforation of the main pulmonary artery by the distal row of the pre-stent and in one case there was also perforation of the subvalvar RVOT. The perforations did not cause clinical complications in any of the presented cases, though the authors do note, however, in 4 patients the perforating stent cell was in proximity or even extending into the adjacent vascular structure including the ascending aorta, left pulmonary vein, and left atrial appendage. Procedural considerations noted by the authors include asymmetrical delivery of the pre-stent due to inability to achieve coaxial alignment of the delivery system and difficulty advancing the 29 mm Sapien valve through the newly implanted pre-stent. The authors propose that perforation did not cause clinical compromise with extravasation of blood due to direct occlusion of the perforation with the device itself or scar tissue filling the potential space that could allow for fluid to accumulate. As such, the authors note that those who have only had a balloon valvuloplasty and no surgical history may be at increased risk of extravasation of blood due to the absence of scar tissue. The authors note that this study was designed to explain the phenomenon and ensure implanters are aware of the potential clinical significance. A larger study designed to determine risk factors, incidence, and implications of this phenomenon is needed.

Percutaneous Balloon-Expandable Stent Implantation to Treat Transverse Aortic Arch Obstruction: Medium- to Long-Term Outcomes of a Retrospective Multicenter Study. Salavitabar A, Eisner M, Armstrong AK, Boe BA, Chisolm JL, Cheatham JP, Cheatham SL, Forbes T, Jones TK, Krings GJ, Morray BH, Steinberg ZL, Akam-Venkata J, Voskuil M, Berman DP. Circ Cardiovasc Interv. 2024 Jul;17(7):e013729. doi: 10.1161/CIRCINTERVENTIONS.123.013729. Epub 2024 Apr 26. PMID: 38666384 Take-home Points: Percutaneous stent implantation for treatment of transverse aortic arch obstruction has high rates of technical and procedural success. The procedure demonstrates a favorable safety profile with a low incidence of serious complications. Despite initial success, a considerable number of patients (41%) required reinterventions over time. Commentary from Dr. Milan Prsa (Switzerland, Europe), section editor of Congenital Heart Disease Interventions Journal Watch: This retrospective, international, multicenter study evaluated the efficacy and safety of percutaneous stent implantation for treating transverse aortic arch (TAA) obstruction. Conducted from July 2002 to December 2017, the study included 146 patients (median age 14.3 [IQR 9.3-19] years, weight 53 [IQR 30-69] kg, follow-up 53 [IQR 12–120] months), analyzing technical outcomes, procedural success, complications, and the necessity for subsequent reinterventions and long-term hypertension management. Technical and procedural success was defined by successful stent placement and a residual aortic arch gradient of ≤10 mmHg, respectively. Most (74%) interventions were following a previous surgical or percutaneous procedure. The intervention exhibited a 100% technical success rate and an 88% procedural success rate. An arch vessel was overlapped by a stent in 81% of cases, most commonly the left subclavian artery (65%) and almost always (98%) intentionally. Balloon dilation of a stent side cell was performed in 22% of cases to improve flow to an arch vessel. Stent design, particularly the use of open cell stents, contributed to the overall success and adaptability of the procedure across varied anatomical challenges. Complications (e.g. aortic injury, stent migration/fracture, vascular injury) during and immediately after the procedure occurred in 14% of cases, and during follow-up in 12% of cases. Notably, 41% of patients underwent reinterventions (47% balloon angioplasty of stents and 47% additional stent implantation), indicating a significant recurrence of aortic obstruction or related complications over time. A residual gradient >10 mmHg was associated with increased odds of reintervention. Hypertension improved from baseline to most recent follow-up (68% to 46% of patients, p<0.05) with a concomitant increase in the use of antihypertensive medications (47% to 60% of patients, p<0.05). This study, which has the largest sample size and longest follow-up to date, underscores the procedural reliability and clinical efficacy of percutaneous stent implantation in managing TAA obstruction. Despite a lack of strict inclusion and exclusion criteria, as well as a standardized approach to clinical and imaging follow-up, the study shows substantial improvements in medium to long-term outcomes. Nevertheless, the high rate of reinterventions calls for ongoing surveillance and management strategies to address related complications and the progressive nature of TAA obstruction.

Radiation Reduction in Paediatric Cardiac Catheterization: We Can Go Even Lower. Finke T, Mainzer G, Yitzhak Y, Devadas S, Mroczek D, Benson LN, Borik S. CJC Pediatr Congenit Heart Dis. 2024 May 31;3(4):129-136. doi: 10.1016/j.cjcpc.2024.05.004. eCollection 2024 Aug. PMID: 39493664 Free PMC article. Commentary by Dr. Lahiri, section editor of Congenital Heart Disease Interventions Journal Watch: The authors state that the ALARA principle – "as low as reasonably achievable" – is essential for congenital cardiac catheterization, especially in children who need repeat procedures over their lifespan. The authors then compared the levels of radiation between two large tertiary care catheterization laboratories: one in Israel and one in Canada. The measures used were dose area product (DAP), DAP per body weight, total air kerma, and fluoroscopy time. The cath lab in Israel was labeled as unit A, and the cath lab in Canada was labeled as unit B. Unit A used AlluraClarity with ClarityIQ technology, which reduces noise and enhances image projection while using lower X-ray doses. Pulsed fluoroscopy was performed at 7.5 f/s, and cineangiograms were performed at 15 f/s. The data were compared with the most recently available (June 2011 to May 2014) data for the corresponding procedure types and radiation reduction protocol from the Hospital for Sick Kids, Canada. Radiation Safety Measures Implemented at Safra Children’s Hospital, Sheba Medical Center Fluoroscopy frame rate: 7.5 frames/s Air gap technique for all children below 30 kg Use of minimal magnification during procedures Limited field of view to the minimum necessary Use of “low” radiation preset with brief increases as clinically necessary Fluoroscopy image storage in place of digital imaging Weight-based reductions in preset frame rates Exposure to ionizing radiation as part of the consent process Use of Philips ClarityIQ technology High awareness of all team members to the “as low as reasonably achievable” principle Hiring of a radiation technician devoted to radiation reduction Regular updates to new systems Catheterizations in unit B were performed at 7.5 frames/s for fluoroscopy and 30 frames/s for cineangiography, using similar protocols to those in unit A, with removal of the anti-scatter grid for all patients <20 kg, allowing for data comparison. Unit B procedures were performed, and images were acquired on two Siemens biplane flat-panel detector digital angiographic systems (Artis zee [lab I] and Axiom Artis [lab II]; Siemens Medical Solutions). Center A analyzed 627 cases, and Center B had 2,033 cases. Below is the comparison of radiation between the two hospitals. A Few Interesting Findings: Ionizing radiation was not much different for PDA closures between the two centers. Fluoroscopy times were not different except for 4 procedures (shorter in Center A). The highest radiation exposure was seen, as expected, in pulmonary valve procedures, and the highest fluoroscopy times were in pulmonary valve perforation in both institutions. In summary, the authors show that there could be further reduction of radiation doses across 16 procedure types. This is achievable with newer technology, removal of anti-scatter grids for all patients <30 kg, and increasing awareness. It must be emphasized that fluoroscopy time in pediatrics does not correlate with median radiation doses, which are often used as a benchmark in adult labs. There are timers in pediatric labs built in for fluoroscopy time, which may serve as a good reminder for physicians to step off fluoroscopy during cases. However, these should not be the sole parameters on which to base hospital policies and protocols. In our lab, we use ultra-low fluoroscopy rates of 3.5 f/s and cine-rates of 7.5 f/s, along with increasing awareness among team members, which has resulted in significant improvement in radiation exposure for both us and the patients. Cardiac catheterization is heavily technology dependent. In this modern era of rapidly evolving technology, the safety of both operators and patients will likely improve over time, with an ever-changing goal of decreasing radiation, all while keeping in sync with the concept of ALARA.

Transcatheter pulmonary valve replacement after arterial switch operation. Nageotte S, Salavitabar A, Zablah JE, Ligon RA, Turner ME, El-Said H, Guyon P, Boucek D, Alvarez-Fuente M, McElhinney DB, Balzer D, Shahanavaz S. Catheter Cardiovasc Interv. 2024 Sep;104(3):531-539. doi: 10.1002/ccd.31152. Epub 2024 Jul 20. PMID: 39033329 Take Home Points: TPVR is a viable but challenging option for ASO patients, with a 66% success rate and relatively high risk of coronary compression or aortic root distortion (24% vs. 5–6% in the general TPVR population). Long-term durability concerns remain, with 32% of patients requiring reintervention within 5 years due to stent fracture, restenosis, or endocarditis. Pre-procedural imaging advancements (e.g., 3D CT, AI modeling) could improve patient selection and procedural success, reducing failure rates and complications. Commentary from Dr. Konstantin Averin (Cohen Children’s Heart Center), catheterization section editor of Pediatric Cardiology Journal Watch: The study by Nageotte et al. investigates the feasibility and safety of transcatheter pulmonary valve replacement (TPVR) in patients who have previously undergone an arterial switch operation (ASO) for D-transposition of the great arteries (D-TGA).  While TPVR is a well-established intervention for right ventricular outflow tract (RVOT) dysfunction, patients with prior ASO present unique anatomical and procedural challenges, particularly coronary compression and aortic root distortion. This retrospective multicenter study included 33 patients across nine centers of which TPVR was successfully performed in 22 patients (66%) - Melody (n=19) and SAPIEN (n=3) valves.  Pre-stenting was performed in nearly all cases.  In the cases that were technically successful TPVR significantly improved RVOT obstruction, reducing the RVOT peak gradient from 43 mmHg to 9 mmHg (p<0.001) and resolving pulmonary regurgitation (PR).  Coronary compression was the primary reason for inability to perform TPVR 8 patients (24%) and aortic root distortion with severe aortic regurgitation in 2 (6%).  One case was complicated by valve embolization requiring emergency surgical removal.  During a median follow-up of 4 years, 7 patients (32%) required RVOT reintervention, and 3 cases of endocarditis occurred (2 surgical explants and one being medically treated).  The study is limited by its retrospective design, small sample size, lack of long-term data and heterogeneous patient population. This study provides compelling evidence that TPVR can be an effective strategy for managing RVOT dysfunction after ASO, though higher procedural failure rates and mid-term reinterventions warrant careful patient selection and long-term monitoring.  The high rate of coronary compression and aortic root distortion raises an important question: Can we improve pre-procedural screening of ASO patients with RVOT dysfunction to identify those that will not be able to undergo TPVR?  Emerging computed tomography (CT) and three-dimensional (3D) modeling could eventually provide a non-invasive, pre-procedural risk assessment.  By optimizing selection criteria providers may ultimately be able to decrease the high procedural failure rate in ASO patients being considered for TPVR.