Alan Nugent

Clinical Features and Outcomes of Childhood Dilated Cardiomyopathy Results From a National Population-Based Study

Background— Despite considerable mortality, population-based prognostic factors for childhood dilated cardiomyopathy are lacking. Methods and Results— A population-based cohort study was undertaken of all children in Australia who presented with cardiomyopathy at age 0 to 10 years between January 1, 1987, and December 31, 1996. A single cardiologist analyzed all cardiac investigations, and a single pathologist analyzed histopathological material. There were 184 subjects with dilated cardiomyopathy. Positive viral identification or lymphocytic myocarditis was found in 30 (68.2%) of 44 cases with available early histology and 8 of 9 cases presenting with sudden death. Freedom from death or transplantation was 72% (95% CI, 65% to 78%) 1 year after presentation and 63% (95% CI, 55% to 70%) at 5 years. By proportional hazards regression analysis, risk factors for death or transplantation comprised age >5 years at presentation (hazard ratio 5.6, 95% CI, 2.6 to 12.0), familial dilated cardiomyopathy (hazard ratio, 2.9; 95% CI, 1.5 to 5.6), lower initial fractional shortening z score (hazard ratio per z-score unit, 0.75; 95% CI, 0.65 to 0.87), and failure to increase fractional shortening z score during follow-up (hazard ratio per unit increase, 0.68; 95% CI, 0.58 to 0.79). At follow-up, 78 (44.6%) of 175 cases diagnosed during life have no symptoms and are not taking any cardiac medication. Conclusions— Early mortality is high in childhood dilated cardiomyopathy, but the clinical status of long-term survivors is good. This population-based study identifies children at risk of adverse events.

Endovascular Stenting of Obstructed Right Ventricle–to–Pulmonary Artery Conduits A 15-Year Experience

Background— The optimal treatment for dysfunctional right ventricle–to–pulmonary artery (RV-PA) conduits is unknown. Limited follow-up data on stenting of RV-PA conduits have been reported. Methods and Results— Between 1990 and 2004, deployment of balloon-expandable bare stents was attempted in 242 obstructed RV-PA conduits in 221 patients (median age, 6.7 years). Acute hemodynamic changes after stenting included significantly decreased RV systolic pressure (89±18 to 65±20 mm Hg, P<0.001) and peak RV-PA gradient (59±19 to 27±14 mm Hg, P<0.001). There were no deaths, and, aside from 5 malpositioned stents requiring surgical removal, there were no serious procedural complications. During follow-up of 4.0±3.2 years, 9 patients died and 2 underwent heart transplantation, none related to catheterization or stent malfunction. During 155 follow-up catheterizations in 126 patients, the stent was redilated in 83 patients and additional stents were placed in 41. Stent fractures were diagnosed in 56 patients (43%) and associated with stent compression and substernal location but did not cause acute hemodynamic consequences. By Kaplan-Meier analysis, median freedom from conduit surgery after stenting was 2.7 years (3.9 years in patients >5 years), with younger age, homograft conduit, conduit diameter ≤10 mm, diagnosis other than tetralogy of Fallot, Genesis stent, higher prestent RV:aortic pressure ratio, and stent malposition associated with shorter freedom from surgery. Tricuspid regurgitation and RV function did not change between stent implantation and subsequent surgery. Conclusions— Conduit stenting is an effective interim treatment for RV-PA conduit obstruction and prolongs conduit lifespan in most patients. Stent fractures were common but not associated with significant complications or earlier conduit reoperation.

Clinical Features and Outcomes of Childhood Hypertrophic Cardiomyopathy

Background—Population-based studies have provided insight into the natural history of adult hypertrophic cardiomyopathy, but comparable information for affected children is lacking. Methods and Results—All Australian children who presented with primary cardiomyopathy at 0 to 10 years of age between January 1, 1987, and December 31, 1996, were enrolled in a longitudinal cohort study. A single cardiologist reviewed serial cardiac investigations on each subject. A total of 80 subjects with hypertrophic cardiomyopathy were identified. An underlying syndromal, genetic, or metabolic condition was identified in 46 subjects (57.5%). There were no cases of sudden death at presentation. Left ventricular outflow tract obstruction was present in 32 subjects (40%); right ventricular outflow obstruction was present in 10 (12.5%). Freedom from death or transplantation was 83% (95% CI, 73 to 90) 5 years after presentation and 76% (95% CI, 62 to 86) 10 years after presentation. By proportional-hazards regression analysis, risk factors for death or transplantation included concentric left ventricular hypertrophy, age at presentation <1 year, lower initial fractional shortening Z score, and increasing left ventricular posterior wall thickness relative to body surface area. At the latest follow-up, 54 of 65 surviving subjects had no symptoms, and 46 were receiving no regular medication. Conclusions—Syndromal, genetic, and metabolic causes predominate in children with hypertrophic cardiomyopathy. Ventricular outflow tract obstruction is common. The clinical status of long-term survivors is good. This population-based study identifies children with hypertrophic cardiomyopathy who are at risk of adverse events.

Pulmonary artery stents: Long-term follow-up†

Objectives: Determine the long‐term outcomes of branch pulmonary artery (PA) stents. Background: PA stents in congenital heart disease effectively relieve stenoses in the short‐term. Published long‐term data are limited. Methods: Patients enrolled in an FDA IDE protocol from 1989–92 were included. Clinical follow‐up and catheterization data were evaluated. Patients were included if >5 year follow‐up data was available or if mortality occurred following the initial procedure. Results: There were five deaths: four due to progression of their underlying heart disease, and one from a complication during a follow‐up catheterization. Clinical data for 43 surviving patients demonstrated 39 patients (91%) are in NYHA class I or II. Seven patients underwent surgical intervention during the follow‐up period (five RV‐PA conduit, two Fontan revisions), but none addressed PA stenosis. Final repeat catheterizations were performed in 36 patients (55 stents) 7.2 ± 4.3 years post stent insertion with 1.2 ± 0.9 further procedures with stent dilations. In this subgroup, the minimum vessel diameter increased from 4.7 ± 1.8 to 13.4 ± 2.4 mm (P < 0.001), and the pressure gradient improved from 41 ± 25 to 9 ± 11 mm Hg (P < 0.001). Higher initial gradient and smaller balloons were associated with a final stent diameter of <14 mm (P = 0.030 and 0.046). Jailed vessels occurred in 49% of stents with abnormal angiographic flow in 18/55. Six repeat catheterizations resulted in complications, including the one procedural death. Conclusion: Stents implants for PA stenoses provide effective improvement in vessel caliber in the long‐term. Although repeat interventions are necessary, this procedure reduces RV pressure and provides an important alternative to surgery for residual PA obstruction.

Outcomes of transcatheter occlusion of patent ductus arteriosus in infants weighing ≤ 6 kg.

OBJECTIVES We sought to analyze the outcomes of transcatheter patent ductus arteriosus (PDA) occlusion using a variety of devices in infants weighing ≤6 kg. BACKGROUND Indications for transcatheter closure of a PDA in infancy include congestive heart failure and/or failure to thrive. Devices available for small infants may be problematic for various reasons, including sheath size, stiffness of delivery system, and anchoring and retrievability characteristics of the device. The Amplatzer Ductal Occluder is approved by U.S. Food and Drug Administration for children weighing >6 kg and older than 6 months of age. METHODS We performed a multicenter, retrospective analysis of children weighing ≤6 kg in whom transcatheter PDA occlusion was attempted between January 1995 and November 2005 at Texas Childrens Hospital and January 2001 to November 2005 at Childrens Hospital of San Diego. RESULTS A total of 62 patients underwent attempted closure. The mean age at catheterization was 4.7 ± 2.8 months with a mean weight at catheterization of 4.6 ± 0.9 kg. Successful device placement was achieved in 58 of 62 patients (94%). Among those receiving a device, complete occlusion was noted in all 58 patients at either catheterization or last available follow-up. CONCLUSIONS Percutaneous closure of PDA should be considered even in infants ≤6 kg.

Comparison of conventional and cutting balloon angioplasty for congenital and postoperative pulmonary vein stenosis in infants and young children

Background: Pulmonary vein stenosis (PVS) is a rare and often lethal condition in children. The optimal treatment for congenital and postoperative PVS is unknown. Methods and Results: We compared outcomes of conventional balloon angioplasty performed for PVS from 1999 to 2003 against cutting balloon angioplasty performed from 2004 to 2007. A total of 100 previously undilated pulmonary veins in 54 patients were studied: 48 veins dilated with conventional balloons and 52 with cutting balloons. Acute results included significantly reduced gradients and increased lumen diameters with both treatments. Acutely, cutting balloon angioplasty and conventional angioplasty yielded similar relative reduction of the PVS gradient (median 78% vs. 63%, P = 0.08) and increase in lumen diameter (median 77% vs. 59%, P = 0.07). There was one procedural death of a critically ill infant, and four cardiac arrests, but no adverse events necessitating surgical intervention. Survival free from reintervention was poor in both groups, and shorter in the cutting balloon group (73% at 1 month, 11% at 6 months, and 4% at 1 year) than in the conventional angioplasty group (77% at 1 month, 35% at 6 months, and 23% at 1 year; P = 0.01). Conclusions: Both conventional and cutting balloon angioplasty were effective at decreasing gradient and increasing lumen size acutely in patients with congenital and postoperative PVS, but reintervention was common with both treatments. Both methods of angioplasty provided limited benefit, and neither was curative for this complex disease.

Outcomes After Stent Implantation for the Treatment of Congenital and Postoperative Pulmonary Vein Stenosis in Children

Background— Pulmonary vein stenosis (PVS) is a rare condition that can lead to worsening pulmonary hypertension and cardiac failure in children, and it is frequently lethal. Surgical and transcatheter approaches are acutely successful but restenosis is common and rapid. Methods and Results— We reviewed outcomes among patients who underwent transcatheter pulmonary vein stent implantation for congenital or postoperative PVS at <18 years of age. A total of 74 pulmonary veins were stented with bare metal, drug-eluting, or covered stents in 47 patients. Primary diagnoses included PVS associated with anomalous venous return in 51%, PVS associated with other congenital cardiovascular defects in 36%, and congenital (“de novo”) PVS in 13% of patients. Median age at the time of pulmonary vein stent implantation was 1.4 years. During a median cross-sectional follow-up of 3.1 years, 21 patients died. Estimated survival was 62±8% at 1 year and 50±8% at 5 years after pulmonary vein stent implantation. Stent placement acutely relieved focal obstruction in all veins. Of the 54 stents reexamined with catheterization, 32 underwent reintervention. Freedom from reintervention was 62±7% at 6 months and 42±7% at 1 year. Stent occlusion was documented in 9 cases and significant in-stent stenosis in 17 cases. Stent implantation diameter ≥7 mm was associated with longer freedom from reintervention (hazard ratio, 0.32; P=0.015) and from significant in-stent stenosis (hazard ratio, 0.14; P=0.002). Major acute complications occurred in 5 cases. Conclusions— Transcatheter stent implantation can acutely relieve PVS in children, but reintervention is common. Larger stent lumen size at implantation is associated with longer stent patency and a lower risk of reintervention.

Stent fractures in congenital heart disease

To describe incidence, characteristics, predictive factors, and sequelae of stent fractures in congenital heart disease.

Incomplete Endothelialization and Late Development of Acute Bacterial Endocarditis After Implantation of an Amplatzer Septal Occluder Device

A 4-year-old girl with a history of a moderate-sized secundum atrial septal defect and mild mitral valve prolapse underwent transcatheter closure with a 22-mm Amplatzer septal occluder (ASO) (AGA Medical Corporation, Golden Valley, Minn) device. Approximately 12 months later, she presented to the emergency department in septic shock with a 5-day history of fevers up to 105°F and was transferred to the pediatric intensive care unit. Her blood and urine cultures grew methicillin-sensitive Staphylococcus aureus within 24 hours. Multiple septic emboli were found on a brain magnetic resonance imaging scan. A transthoracic echocardiogram revealed vegetations on the mitral and tricuspid valves (Figures 1 and 2⇓ and Movies I and II), with a perforation in the mitral valve and severe mitral insufficiency. The patient was taken to the cardiovascular operating room, and severe mitral and tricuspid valve endocarditis was …

Use of suture‐mediated vascular closure devices for the management of femoral vein access after transcatheter procedures

Groin complications remain the most common complication of cardiac catheterization procedures. While the use of closure devices is increasing for arterial sheaths, venous sheaths tend to be removed and hemostasis achieved with manual compression. We report our experience using Perclose suture‐mediated vascular closure device to achieve hemostasis and early mobility in patients who have had venous access as part of their procedure. There were a total of 42 patients (21 males; average age, 63.5 years) studied. The majority of the patients had 7 Fr sheaths (24), with access sites of sheaths up to 14 Fr being closed with this technique. Two patients developed complications at the access site: one patient requiring rehospitalization for intravenous antibiotics because of late access site infection, and one patient with deep venous thrombosis and pulmonary emboli. We conclude that the use of the Perclose suture‐mediated closure device for closure of femoral venous access sites is feasible and should be considered especially in patients with larger venous sheaths and those at increased risk of groin complications. Catheter Cardiovasc Interv 2004;63:439–443.