Daniel S. Levi

Embolization and retrieval of the Amplatzer septal occluder

Embolization and percutaneous retrieval of the Amplatzer septal occluder (ASO) after release have been reported. However, the incidence, the causes of embolization, and the methods for effective retrieval have not been systematically described. In a survey of the ASO company‐designated proctors, the incidence of ASO embolization in this groups experience was 0.55% (21 embolizations in 3,824 device placements) with a wide range of patient demographics, atrial septal defect (ASD) sizes, and device sizes. Most embolizations occurred because of inadequate rim or undersized devices. Of the 21 embolizations, 15 of the devices were retrieved percutaneously with a gooseneck snare without morbidity or mortality. Six were retrieved at surgery. Of the 21 patients, 12 had ASO closure of their ASDs, and 9 had surgical ASD closure. In vitro, all devices could be retrieved with sheathes 2 Fr sizes larger than their recommended delivery sheath. Any device larger than 26 mm could be retrieved with its delivery sheath. The ability to pull the snared button into a sheath was variable and was assisted by pulling the device from above with a bioptome and by using a rigid notched sheath. Because the incidence of ASO embolization is about 1 in 200 in the most experienced hands, all operators should be prepared with the techniques and equipment required for percutaneous ASO retrieval. Catheter Cardiovasc Interv 2004;61:543–547.

Melody Valve Implant Within Failed Bioprosthetic Valves in the Pulmonary Position A Multicenter Experience

Background—Transcatheter pulmonary valve implantation using the Melody valve has emerged as an important therapy for the treatment of postoperative right ventricular outflow tract dysfunction. Melody-in-bioprosthetic valves (BPV) is currently considered an off-label indication. We review the combined experience with transcatheter pulmonary valve implantation within BPVs from 8 centers in the United States and discuss technical aspects of the Melody-in-BPV procedure. Methods and Results—A total of 104 patients underwent Melody-in-BPV in the pulmonary position at 8 US centers from April 2007 to January 2012. Ten different types of BPVs were intervened on, with Melody valve implantation at the intended site in all patients. Following Melody valve implant, the peak right ventricle-to-pulmonary artery gradient decreased from 38.7±16.3 to 10.9±6.7 mm Hg (P<0.001), and the right ventricular systolic pressure fell from 71.6±21.7 to 46.7±15.9 mm Hg (P<0.001). There was no serious procedural morbidity, and no deaths related to the catheterization or implant. At a median follow-up of 12 months (1–46 months), no patients had more than mild regurgitation, and 4 had a mean right ventricular outflow tract gradient ≥30 mm Hg. During follow-up, there were 2 stent fractures, 3 cases of endocarditis (2 managed with surgical explant), and 2 deaths that were unrelated to the Melody valve. Conclusions—Transcatheter pulmonary valve implantation using the Melody valve within BPVs can be accomplished with a high rate of success, low procedure-related morbidity and mortality, and excellent short-term results. The findings of this preliminary multicenter experience suggest that the Melody valve is an effective transcatheter treatment option for failed BPVs.

Use of assist devices and ECMO to bridge pediatric patients with cardiomyopathy to transplantation

BACKGROUND Pulsatile ventricular assist devices (VADs) are used to bridge adults with end-stage heart disease to transplantation. A combination of external implantable pulsatile and continuous-flow external mechanical support now can be used to bridge pediatric patients with end-stage cardiomyopathy to orthotopic heart transplantation (OHT). METHODS We reviewed consecutive pediatric patients with cardiomyopathy (n = 28) who required mechanical cardiac support from July 1995 to February 2001. All were OHT candidates with severe hemodynamic compromise despite maximal medical support. We excluded from this series patients who had undergone cardiotomy. RESULTS Nineteen patients received support from external continuous-flow devices, either with extracorporeal membrane oxygenation or with centrifugal VADs, and 9 patients received pulsatile support. Nineteen of 28 (68%) patients were successfully bridged to transplant (17) or weaned (2) from their devices after recovery. Of the patients successfully bridged to transplant or recovery, 89% are alive to date. Univariate analysis revealed that a lower bilirubin concentration after 2 days of support was associated with a favorable outcome (p = 0.006). As expected, the patients with pulsatile VADs had significantly higher rates of extubation and oral feeding. CONCLUSION Pulsatile and continuous-flow devices can complement each other to significantly extend the lives of a wide range of pediatric patients with severe cardiomyopathies.

Diagnosis and treatment of pediatric viral myocarditis.

Acute myocarditis is characterized by the rapid development of life-threatening congestive heart failure and arrhythmias. Although the initial stages of this disorder apparently result from direct cytopathic effects on the atrial and ventricular myocardium, later stages of progressive decompensation may result from immune-mediated myocyte destruction. There has been recent improvement in understanding the role of this immunologic cascade. As a result, treatment now begins earlier in the course of the disease and can target both the virus and the immune response. Our ability to implement mechanical support in children as a bridge to transplant or recovery, even in children presenting in the final stages of their disease, has led to an improved outcome regarding morbidity and mortality.

Smart Materials Applications for Pediatric Cardiovascular Devices

“Smart Materials” are materials that change their shape, color, or size in response to an externally applied stimulus. While smart materials have already made a tremendous impact on our lives through their applications in liquid crystal displays, headphones, fuel injection systems, flexible cell phone antennas, and many other commercial products, they also have the potential to help many pediatric patients. This review focuses on with the present and potential applications of shape memory alloys, piezoelectric materials, and the relatively newer class of materials called magnetostrictive and ferromagnetic shape memory alloys in the design of pediatric cardiovascular devices.

Interventional treatment of patent ductus arteriosus in 2004

In 2004, the interventional treatment of patent ductus arteriosus (PDA) is definitive and curative. In current practice, coils are used for smaller PDA, and devices are employed for larger PDA. Developing technologies offer small improvements in control and results, but do not appear to promise major changes in practice. This review summarizes the current and emerging interventional technologies directed at PDA closures. Catheter Cardiovasc Interv 2005;64:91–101.

Transcatheter closure of coronary artery fistulae using the Amplatzer duct occluder

Objective: The aim of this study is to report our experience using the Amplatzer Duct Occluder (ADO) for occlusion of significant coronary artery fistulae (CAF). Background: Transcatheter closure of CAF with coils is well described. Use of newer devices may offer advantages such as improved control of device placement, use of a single instead of multiple devices, and high rates of occlusion. Methods: A retrospective review of all patients catheterized for CAF from July 2002 through August 2005 was performed. Results: Thirteen patients with CAF underwent cardiac catheterization, of which a total of 6 patients had ADO placement in CAF (age, 21 days to 56 years; median age, 4.3 years and weight, 3.8 kg to 74.6 kg; median weight, 13.3 kg). An arteriovenous wire loop was used to advance a long sheath antegrade to deploy the ADO in the CAF. Immediate and short‐term outcomes (follow‐up, 3 months to 14 months; median follow‐up, 8.5 months) demonstrated complete CAF occlusion in 5 patients and minimal residual shunt in 1 patient (who had resolution of right atrial and right ventricular enlargement). On follow‐up clinical evaluation, all 6 patients had absence of fistula‐related murmurs, and 2 previously symptomatic patients had resolution of congestive heart failure symptoms. Early complications included transient palpitations and atrial arrhythmia in the 2 oldest patients (52 and 56 years old). Conclusions: Use of the ADO is applicable for transcatheter closure of significant CAF. Advantages of using the ADO include the antegrade approach, use of a single device, and effective CAF occlusion.

Diverse morphologic manifestations of cardiac allograft vasculopathy: A pathologic study of 64 allograft hearts

BACKGROUND Cardiac allograft vasculopathy (CAV) is a major limitation to the long-term success of cardiac transplantation. Although there are published descriptions of the lesions, there have been no studies delineating the pathology of CAV in a large series of patients who underwent retransplantation for CAV. METHODS We reviewed archival records and microscopic sections of surgically explanted hearts from 64 patients who underwent cardiac retransplantation: 54 adults (18 to 70 years old) and 10 children (3 to 15 years old). Vascular lesions were categorized as showing intimal fibromuscular hyperplasia, atherosclerosis and/or inflammation. The degree of luminal narrowing was estimated from gross descriptions and microscopic sections. RESULTS In total, 75% of hearts had evidence of acute cellular rejection, mostly mild. Intramyocardial arteries showed primarily intimal fibromuscular hyperplasia and inflammation with no atheromas present. Large and branch epicardial coronary arteries were narrowed in at least one artery of all hearts. Lesions in the epicardial coronary arteries were composed of intimal fibromuscular hyperplasia, atherosclerosis and/or inflammation affecting one or more vascular layers (intima, media and adventitia). Severe CAV with >75% luminal narrowing was seen in the LAD in 17% of hearts, the LCx in 17% and the RCA in 22% of hearts. Two hearts had severe narrowing of the left main coronary artery. Nineteen arteries had luminal thrombi. All hearts had narrowing of smaller epicardial branch coronary arteries that was often severe. Atheromas were present in arteries of adults and children; thus, not all atheromas could be considered pre-existing prior to transplantation. Both arteries and veins showed intimal hyperplasia and inflammation. CONCLUSIONS CAV is a pathologically multifaceted disorder that affects large and small epicardial coronary arteries of adults and children, with different types of lesions: intimal fibromuscular hyperplasia; atherosclerosis; and/or inflammation (vasculitis). Therapies to address this disease must take into account the protean nature of the vascular lesions.

Staged repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries: Experience with 104 patients

OBJECTIVE To determine the early and intermediate-term outcome of the staged repair used to treat children with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries. METHODS We reviewed a retrospective case series of 104 patients with this complex lesion. Information was obtained from medical records and referring physicians. RESULTS Of the 104 patients treated with the staged repair, 58 achieved completion of anatomic repair. The 10-year mortality was 16.5%. In the patients with complete repair, the median right-to-left ventricle pressure ratio was 0.5. The overall surgical reoperation rate was 17%, and 15.5% of patients required postoperative interventional cardiac catheterization. In the multivariate analysis, the number of collateral vessels incorporated in the repair was found to be an independent risk factor for postoperative mortality and an elevated right-to-left ventricle pressure ratio after complete repair. CONCLUSION The staged repair can be successfully used to treat patients with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries. This method yields a relatively low mortality with good functional results.

Stent Implantation for Coarctation of the Aorta in Children <30 kg

OBJECTIVES Our aim was to determine key characteristics of stents commonly implanted in the aorta through bench testing and to describe our technique and acute results in patients weighing <30 kg. BACKGROUND Despite the increasing use of stents for interventional treatment for coarctation of the aorta (CoA) in larger patients, use of large stents is controversial in small children. METHODS Methods included bench testing of large stents, and retrospective review of all patients over 1 year of age who had stent implantation for treatment of CoA. Patients were divided into 2 groups based on weight. Paired comparisons were made before and after stent implantation, and group outcomes were compared. RESULTS Sixty patients comprised the entire sample, with 22 patients assigned to group I (<30 kg) and 38 patients assigned to group II (>or=30 kg). The mean minimum diameters of the CoA (group I 5.0 to 10.7 mm; group II 8.0 to 15.0 mm) and the ratio of the coarctation diameter to the descending aorta diameter measured at the level of the diaphragm (CoA/DAo ratio) (group I 0.4 to 0.93; group II 0.46 to 0.94) increased significantly in both groups (all p < 0.05). The mean systolic gradient decreased significantly in both groups (group I 23.0 to 2.0 mm Hg; group II 24.0 to 2.8 mm Hg; both p = 0.001). No difference was found between the groups in the CoA/DAo ratio, residual systolic gradients, or the decrease in systolic gradient after stent implantation. There were no significant complications in patients under 30 kg. CONCLUSIONS As in larger patients, use of large stents for treatment of CoA in small children is effective and safe in the short term. In these patients, stent redilations will be required, and follow-up is ongoing.