Joanne L. Chisolm

The Retrograde Aortic Arch in the Hybrid Approach to Hypoplastic Left Heart Syndrome

BACKGROUND Before palliative stage 2 for hypoplastic left heart syndrome, the coronary and cerebral circulations are often dependent on retrograde perfusion by means of the aortic arch. Results of hybrid palliation with a focus on patients exhibiting retrograde aortic arch obstruction (RAAO) were analyzed. METHODS From July 2002 to March 2008 66 consecutive hybrid procedures for hypoplastic left heart syndrome were performed. Patients requiring RAAO intervention based on cardiology-surgery consensus were defined as group 1 (n = 16), whereas all other hypoplastic left heart syndrome patients formed group 2 (n = 50). RESULTS At birth there were no differences between groups in terms of demographics or cardiac function. Group 1 had more patients with aortic atresia (94% versus 58%; p = 0.01), and 69% of patients had initial echocardiographic comments regarding incipient RAAO versus 26% in group 2 (p = 0.007). The type of ductal stent, balloon versus self-expandable, did not influence the subsequent development of RAAO. Before RAAO intervention (mean age, 74 days), group 1 patients had significantly more tricuspid regurgitation. The main treatment for RAAO in group 1 was coronary stent insertion, with 3 patients having a reverse central shunt. At a mean follow-up of 611 days, group 1 had reduced survival interstage (56.3% versus 88%; p = 0.005) and overall (43.7% versus 70%; p = 0.03). CONCLUSIONS Clinically important RAAO occurred in 24% of the hypoplastic left heart syndrome patients in this series. If RAAO is detected at birth or early interstage, a Norwood operation is now favored. Palliative interventional catheterization remains very important mid and late interstage for continuing the hybrid strategy toward comprehensive stage 2.

Atrial septal interventions in patients with hypoplastic left heart syndrome

Objectives: To report an institutional experience performing percutaneous atrial septal interventions in patients with hypoplastic left heart syndrome (HLHS). Background: The success of the Hybrid approach in palliating patients with HLHS is crucially dependant on relieving any significant interatrial restriction. Data on transcatheter interventions to relieve atrial septal restrictions in patients with HLHS are limited. Methods: We retrospectively reviewed 67 transcatheter atrial septal interventions that were performed between July 2002 and September 2007 in 56 patients with HLHS. The median weight was 3.35 kg. About 10.7% of patients had an intact atrial septum. Balloon atrial septostomy (BAS) was used in 77.6% of procedures, additional techniques in 35.8% of procedures. Patients were divided into those with standard atrial septal anatomy (group A, n = 33) and those with complex atrial septal anatomy (group B, n = 23). Results: The mean trans‐septal gradient was reduced significantly from 7 mm Hg to 1 mm Hg with the median time to discharge being 3.5 days. Major adverse events were seen in 8.9% of procedures, whereas minor adverse events occurred in 26.8% of procedures. Adverse events were significantly less common in patients with standard atrial septal anatomy, compared to those with complex atrial septal anatomy (25.6% versus 50.0%). About 19.6% patients required repeated atrial septal interventions. Survival up to and including Comprehensive stage II palliation was 73% group A, and 57% in group B. Conclusions: With utilization of appropriate techniques and equipment, atrial septal interventions in HLHS can be performed successfully in virtually all patients. Complex atrial septal anatomy is technically challenging and has a higher incidence of procedural adverse events. In the majority of patients, standard BAS can be performed safely, and is usually the only intervention required to achieve adequate relief of atrial septal restriction until Comprehensive stage II palliation.

The medtronic melody® transcatheter pulmonary valve implanted at 24-mm diameter—it works

We report the Melody valve implanted and/or expanded to 24‐mm diameter.

Hybrid procedures: adverse events and procedural characteristics--results of a multi-institutional registry.

INTRODUCTION Procedural cooperation between cardiac surgeon and interventional cardiologist to facilitate interventions such as device delivery or angioplasty (hybrid procedure) has become increasingly common in the management of patients with congenital heart disease. DESIGN Data were prospectively collected using a multicenter registry (C3PO). Between February 2007 and December 2008, seven institutions submitted data regarding 7019 cardiac catheterization procedures. Procedural data and adverse events (AEs) of 128 hybrid procedures were evaluated. RESULTS There was significant variability in the number of hybrid procedures per center, ranging from one to 89 with a median of eight. A total of 60% of interventional (vs. strictly diagnostic) hybrid procedures were performed by one center. The median weight was 3.7 kg (0.7-86 kg). Single-ventricle circulation was present in 60% of the procedures. Hybrid procedures included: patent ductus arteriosus (PDA) stent placement (n = 55), vascular rehabilitation (n = 25), ventricular septal defect (VSD) device closure (n = 7), valvotomy (n = 3), and diagnostic hybrid procedures (n = 38). Sixteen AEs occurred in 15/128 (12%) procedures. These included minor or trivial AEs (n = 9), moderate AEs (n = 5), major AEs (n = 1), and catastrophic AEs (n = 1). The type of AE documented included arrhythmias (n = 6), hypoxia or hypotension (n = 3), vessel or cardiac trauma (n = 2), and other events (n = 5). Of documented AEs, 9/16 (56%) were classified as not preventable, 6/16 (38%) as possibly preventable, and 1/16 (6%) as preventable. The incidence of AE related to PDA stent placement with surgical exposure (5/50, 10%) was significantly lower when compared with PDA stent placement performed percutaneously (4/5, 80%, P= .002). CONCLUSION Hybrid procedures appear to have a low incidence of associated major AEs. PDA stent placement performed as a palliation of hypoplastic left heart syndrome (HLHS) or complex single/two ventricle patients may have a lower incidence of AEs if performed using a direct approach with surgical exposure rather than a percutaneous approach. Accurate definitions of these innovative procedures are required to facilitate prospective data collection.

Use of a dose‐dependent follow‐up protocol and mechanisms to reduce patients and staff radiation exposure in congenital and structural interventions

Background: Increasingly complex structural/congenital cardiac interventions require efforts at reducing patient/staff radiation exposure. Standard follow‐up protocols are often inadequate in detecting all patients that may have sustained radiation burns. Methods: Single‐center retrospective chart review divided into four intervals. Phase 1 (07/07–06/08, 413 procedures (proc)): follow‐up based on fluoroscopy time only; frame rate for digital acquisition (DA) 30 fps, and fluoroscopy (FL) 30 fps. Dose‐based follow‐up was used for phase 2–4. Phase 2 (07/08–08/09, 458 proc): DA: 30 fps, FL: 15 fps. Phase 3 (09/09–06/10, 350 proc): DA: 15–30 fps, FL: 15 fps, use of added radiation protection drape. Phase 4 (07/10–10/10, 89 proc): DA: 15–30 fps, FL: 15 fps, superior noise reduction filter (SNRF) with high‐quality fluoro‐record capabilities. Results: There was a significant reduction in the median cumulative air kerma between the four study periods (710 mGy vs. 566 mGy vs. 498 mGy vs. 241 mGy, P < 0.001), even though the overall fluoroscopy times remained very similar (25 min vs. 26 min vs. 26 min vs. 23 min, P = 0.957). There was a trend towards lower physician radiation exposure over the four study periods (137 mrem vs. 126 mrem vs. 108 mrem vs. 59 mrem, P = 0.15). Fifteen patients with radiation burns were identified during the study period. When changing to a dose‐based follow‐up protocol (phase 1 vs. phase 2), there was a significant increase in the incidence of detected radiation burns (0.5% vs. 2%, P = 0.04). Conclusions: Dose‐based follow‐up protocols are superior in detecting radiation burns when compared to fluoroscopy time‐based protocols. Frame rate reduction of fluoroscopy and cine acquisition and use of modified imaging equipment can achieve a significant reduction to patient/staff exposure.

Assessment of in-stent stenosis in small children with congenital heart disease using multi-detector computed tomography : A validation study

Objectives: Our purpose was to investigate the diagnostic reliability of multi‐detector computed tomography (MDCT) in assessing in‐stent stenosis compared to digital angiography (DA) in small children. Background: Little is known about the feasibility of using MDCT to assess stents placed to treat children with congenital heart disease (CHD). Methods: Twenty‐two children (median age [range], 2¾ [½ to 12] years) with 42 transcatheter placed stents (median diameter: 7.2 [3.4–16.3] mm) in the pulmonary arteries (n = 36), aorta (2), PDA (1), and SVC (3) underwent both MDCT and DA due to suspected hemodynamic problems. Results: Independent “blinded” observers were able to measure stent and minimal luminal diameters in 115 out of 124 (93%) stent segments on MDCT and DA. The interobserver variability was low (mean difference: 0.5, SD 0.8 mm) with high correlation (r = 0.97; P < .0001). The percent stenosis by MDCT correlated well with DA (r = 0.89, P < .0001; mean error 2.7, SD 10.4%). For all grades of stenosis, the sensitivity and specificity for MDCT were 58% and 97%, respectively. At a threshold of ∼≥20% stenosis sensitivity became >98%. All stent associated complications [fracture (4), vascular narrowings (11)] were diagnosed by MDCT. As the stent diameter increased, there was significantly reduced variability between MDCT and DA for in‐stent stenosis (P < .0001). Conclusion: In small children, MDCT is a feasible and promising method for assessing stent associated complications in the treatment of CHD. Cardiac surgeons and interventional cardiologists might rely on this imaging modality to plan specific interventions more precisely and to assess the results upon follow up.

Accuracy of Imaging Modalities in Detection of Baffle Leaks in Patients Following Atrial Switch Operation

Patients with dextro‐transposition of the great arteries (d‐TGA) status post atrial switch operation are vulnerable to complications such as baffle leaks. The best noninvasive imaging modality to detect baffle leaks is unknown. The purpose of this study was to determine the sensitivity and specificity of different noninvasive imaging modalities in the detection of baffle leaks in this population.

Pulmonary atresia with ventricular septal defect and multifocal pulmonary blood supply: does an intensive interventional approach improve the outcome?

INTRODUCTION Pulmonary atresia with ventricular septal defect (VSD) continues to be associated with significant morbidity and mortality, with significant institutional variation in therapeutic strategies. This study reports a single center experience utilizing an intensive transcatheter approach to promote pulmonary vascular growth. METHODS A retrospective analysis of 20 patients undergoing surgical and transcatheter treatment for pulmonary atresia with VSD between 2002 and 2010. RESULTS The median age at initial surgical palliation was 6.3 months (8 days to 2.5 years). Eleven patients (group 1) underwent initial surgical palliation without VSD closure and nine patients (group 2) underwent an initial complete repair with fenestrated or complete VSD closure. Group 1 had a smaller Nakata index (54 mm2/m2 vs. 134 mm2/m2 , P = .04) and a smaller absolute native pulmonary artery diameter (2.7 mm vs. 4.5 mm, P = .01) than group 2. Intraoperative angiography was performed in 10 cases to evaluate if early transcatheter intervention was warranted. The median follow-up during the study period was 2.3 years (1.6 months to 8.3 years). Of the 16 patients who survived the initial early postoperative period, 15 patients (94%) went on to receive surgical (n = 11) and/or interventional (n = 25) catheterization procedures. There was improvement in the mean Nakata index from the initial presurgical evaluation to the most recent catheterization data (38.4 mm2/m2 vs. 169.7 mm2/m2, P ≤ .05). To date, two of 11 (18%) patients in group 1 ultimately underwent surgical VSD closure. Overall mortality was six of 20 (30%) with four deaths in group 1 and two deaths in group 2. There were no procedural deaths. CONCLUSIONS Combining surgical unifocalization procedures with subsequent early and intensive catheter-based pulmonary artery rehabilitation may improve vascular growth, ultimately rendering many patients suitable for fenestrated VSD closure. Risk stratification, including intraoperative exit angiography, is essential to determine the need for early transcatheter interventions.

Intravascular Ultrasound Characterization of a Tissue-Engineered Vascular Graft in an Ovine Model.

Patients who undergo implantation of a tissue-engineered vascular graft (TEVG) for congenital cardiac anomalies are monitored with echocardiography, followed by magnetic resonance imaging or angiography when indicated. While these methods provide data regarding the lumen, minimal information regarding neotissue formation is obtained. Intravascular ultrasound (IVUS) has previously been used in a variety of conditions to evaluate the vessel wall. The purpose of this study was to evaluate the utility of IVUS for evaluation of TEVGs in our ovine model. Eight sheep underwent implantation of TEVGs either unseeded or seeded with bone marrow-derived mononuclear cells. Angiography, IVUS, and histology were directly compared. Endothelium, tunica media, and graft were identifiable on IVUS and histology at multiple time points. There was strong agreement between IVUS and angiography for evaluation of luminal diameter. IVUS offers a valuable tool to evaluate the changes within TEVGs, and clinical translation of this application is warranted.

Mustard baffle obstruction and leak – How successful are percutaneous interventions in adults?

Atrial switch operations for D-Transposition of the great arteries (D-TGA) were performed until the late 20th century. These patients have substantial rates of re-operation, particularly for baffle related complications. This study sought to analyze the efficacy of percutaneous transcatheter intervention (PTI) for baffle leak and/or stenosis in adult atrial switch patients. Adult patients with a prior atrial switch operation who underwent heart catheterization (2002-2014) at a tertiary adult congenital heart disease referral center were retrospectively analyzed. In 58 adults (30 ± 8 years, 75% men, 14% New York Heart Association (NYHA) functional class ≥2) who underwent 79 catheterizations, PTI was attempted in 50 (baffle leak (n = 10, 20%), stenosis (n = 27, 54%), or both (n = 13, 26%)). PTI was successful in 45 and 5 were referred for surgery due to complex anatomy. A total of 40 bare metal stents, 18 covered stents, 16 occlusion devices, 2 angioplasties, and 1 endovascular graft were deployed. In isolated stenosis, there was improvement in NYHA functional class after PTI (8 vs. 0 patients were NYHA FC > 2, p = 0.004), which was matched by improvement in maximal oxygen consumption on exercise testing (VO2) (25.1 ± 5.4 mL/kg/min vs. 27.9 ± 9 mL/kg/min, p = 0.03). There were no procedure-related deaths or emergent surgeries in this cohort. This single-center cohort is the largest reported series of adult atrial switch operation patients who have undergone PTI for baffle stenosis and/or leak. We demonstrate that PTI with an expert multi-disciplinary team is a safe and effective alternative to surgery in adult patients with an atrial switch operation.