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Biomedical subjects

L N Benson

Publications and source records attributed to L N Benson.

At least 19 recordsLinked to original sources
PubMed2006

Pre-closure of femoral venous access sites used for large-sized sheath insertion with the Perclose device in adults undergoing cardiac intervention.

BACKGROUND: Interventional procedures in adults with congenital cardiac conditions often require insertion of large-sized sheaths into the femoral veins. Data on the use of suture-mediated devices for femoral venous access site closure are scant and no data are available regarding venous patency after device use. OBJECTIVE: To assess the efficacy of the 6Fr Perclose (Abbott Vascular Devices, CA, USA) suture-mediated device in achieving haemostasis and venous patency after closure. DESIGN AND SETTING: 146 consecutive patients (80 women, mean (SD) age 45 (14) years) undergoing closure of 205 femoral venous access sites in a tertiary cardiac centre were studied. All received heparin and were taking concomitant aspirin or clopidogrel, or both. The majority (98%) had a >or=10Fr sheath inserted. RESULTS: Immediate haemostasis was achieved in 202 (99%) sites. Two patients (1.4%) had a major complication. On follow-up (111 patients, mean (SD) 71 (33) days) there was no evidence of haematoma or fistula formation. Doppler studies from a subgroup of 43 (29%) patients (mean (SD) age 45 (15) years, mean (SD) follow-up 47 (18) days) showed a common femoral venous diameter of 11.6 (2.7) mm on the device closed right and 12.2 (2.5) mm on the left vein (p>0.05). All accessed veins were patent with no pseudoaneurysm or arteriovenous fistula formation. CONCLUSION: Pre-closure of large-size sheath femoral venous access sites using the suture-mediated Perclose device is efficacious in achieving rapid haemostasis in the presence of anticoagulation. Doppler follow-up shows no loss of venous patency or luminal venous diameter as compared with the contralateral side.

Aged↗
PubMed2006

The use of carvedilol in pediatric heart failure.

Chronic congestive heart failure has become a significant medical burden in the adult and a growing problem in the pediatric age group. While the etiologies of heart failure differ between children and adults, applied medical therapies are generally the same. In this regard, over the last decade, beta-adrenergic receptor blockade has become an important component in drug therapy of congestive heart failure in the adult population. A third-generation beta-blocker, carvedilol, has now been shown in adult trials to be efficacious in the treatment of heart failure and has been shown to be superior to other similarly used beta-blockers. Carvedilol use has been adapted into pediatric heart failure practice although data supporting its efficacy in infants and children are scarce. This review will describe the application of carvedilol in the adult, as it pertains to pediatric practice, review the existing pediatric literature and describe our institution's experience with carvedilol in heart failure therapy.

Adrenergic beta-Antagonists↗
PubMed2005

Implantation of endovascular stents for the obstructive right ventricular outflow tract.

OBJECTIVES: To evaluate the effectiveness and long term outcomes of catheter intervention for obstructive conduits between the right ventricle and pulmonary arteries. DESIGN: Retrospective chart review. SETTING: Tertiary care paediatric cardiology unit. PATIENTS AND INTERVENTIONS: 70 procedures in 68 children (median age at intervention 6 years, median interval after conduit insertion 3.4 years) were analysed. All children had haemodynamic indications for conduit replacement. Twenty four children underwent a second intervention (stent dilatation in 17, second stent implantation in seven). RESULTS: Mean (SD) conduit pressure gradient decreased from 44 (18) mm Hg to 18 (12) mm Hg at the initial intervention (n = 62, p < 0.001) and from 39 (15) mm Hg to 23 (10) mm Hg at the second intervention (n = 16, p < 0.001). The percentage of the predicted right ventricular outflow area increased from 17 (9)% to 44 (22)% at the initial intervention (n = 62, p < 0.001) and from 24 (8)% to 29 (11)% at the second intervention (n = 21, p < 0.001). The conduit was subsequently replaced in 33 children. Freedom from conduit replacement from the time of stent implantation was 83%, 75%, and 47% at one, two, and five years, respectively, and from the time of the initial conduit surgery it was 87%, 64%, and 42% at five, eight, and 10 years, respectively. Body growth was maintained, no deaths were reported during follow up, and pulmonary insufficiency was well tolerated. CONCLUSION: A catheter treatment strategy for obstructive conduits is safe and effective in prolonging conduit function.

Adolescent↗
PubMed2003

Transcatheter management of residual shunts after initial transcatheter closure of a patent arterial duct.

OBJECTIVES: To assess the efficacy and safety of transcatheter reocclusion of persistent leaks following previously attempted transcatheter occlusion of persistent arterial duct. DESIGN: Retrospective study. SETTING: Tertiary pediatric cardiology centre. PATIENTS: From February 1987 through October 1996, trans-catheter occlusion of a residual ductal shunt was attempted in 42 consecutive patients at a median age of 5.0 years (range 1.6 years to 16.2 years). INTERVENTIONS: Fourty patients had successful placement of a double umbrella occluder (n=27) or coils (n=13) across residual shunts. Complications included device embolization in two patients and hemolysis in one patient. OUTCOME MEASURES AND RESULTS: Mean z-score for left ventricular end-diastolic dimension (LVEDD) at initial echocardiography was +2.55 +/- 1.89 (P<0.0001 versus normal); z-score for left pulmonary artery (LPA) diameter was +2.00 +/- 1.52 (P<0.0001). Mean LPA to right pulmonary artery (RPA) diameter ratio was 1.05 +/- 0.18. At follow-up echocardiogram, a median of two years (range six months to 7.7 years) after the second procedure, a shunt was persistent in 3% of the patients. Mean LVEDD and LPA diameter z-value, and mean LPA to RPA diameter had dropped significantly to +0.42 +/- 1.31, +0.07 +/- 1.15 and 0.86 +/- 0.14 (P<0.001), respectively. LPA flow acceleration was present in 25% of patients. Three of nine patients, in whom lung perfusion scan was performed, had left lung perfusion below 40%. Small weight and age at catheterization were significant risk factors for LPA flow disturbance. CONCLUSIONS: Repeat transcatheter occlusion is safe and successful in eliminating residual shunt across the arterial duct. Attention should, however, be addressed to the potential for LPA stenosis and growth, and flow should be regularly assessed.

Adolescent↗
PubMed2002

Silent and audible persistent ductus arteriosus: an angiographic study.

Persistent ductus arteriosus (PDA) murmurs become silent probably due to the direction of the jet across the ductus arteriosus when entering the pulmonary artery. Out of 15 children with silent PDA, 14 demonstrated a ductal flow not contacting and away from the anterior wall of the main pulmonary artery. In 15 children with a continuous murmur caused by a PDA, 12 exhibited a ductal flow toward and reaching the anterior wall of the MPA. There was no correlation between the presence of a murmur and the size of the arterial duct in this study.

Angiography↗
PubMed2001

Right ventricular form and function after percutaneous atrial septal defect device closure.

OBJECTIVES: We sought to assess the right heart's response to percutaneous device closure of moderate sized atrial septal defects (ASDs) in adults over a one-year follow-up period. BACKGROUND: Percutaneous ASD device closure is a safe and effective means of reducing or eliminating interatrial shunting. The response of the adult's right heart to device closure is incompletely understood. METHODS: Forty consecutive patients had 40 device implantations (32 with the CardioSeal implant and 8 with the Amplatzer device). The patients were assessed with echocardiography, chest radiography and electrocardiography before the procedure and at 1, 6 and 12 months. RESULTS: The mean ASD size was 13+/-4 mm, and the device size ranged from 33 to 40 mm for CardioSeal and 12 to 36 mm for Amplatzer. At one month, heart size (49% vs. 46%), four-chamber right ventricular (RV) size (45 vs. 41 mm), paradoxical septal motion (60% vs. 5%), QRS duration (125 vs. 119 ms), PR interval (181 vs. 155 ms) and echocardiographically determined pulmonary artery systolic pressure decreased significantly and was maintained at 12-month follow-up. At six months, right atrial length decreased from 50 to 47 mm. At one year, 29% of patients had persistent RV enlargement. CONCLUSIONS: Right heart morphology undergoes rapid improvement within one month of defect closure, with associated mechanoelectrical benefit. A small number of patients had persistent RV enlargement or pulmonary hypertension, or both, at one year. Our data support the application of transcatheter methods in achieving excellent hemodynamic and anatomic outcomes.

Adult↗
PubMed2001

ABO-incompatible heart transplantation in infants.

BACKGROUND: Transplantation of hearts from ABO-incompatible donors is contraindicated because of the risk of hyperacute rejection mediated by preformed antibodies in the recipient to blood-group antigens of the donor. This contraindication may not apply to newborn infants, who do not yet produce antibodies to T-cell-independent antigens, including the major blood-group antigens. METHODS: We studied 10 infants 4 hours to 14 months old (median, 2 months) who had congenital heart disease or cardiomyopathy and who received heart transplants from donors of incompatible blood type between 1996 and 2000. Serum isohemagglutinin titers were measured before and after transplantation. Plasma exchange was performed during cardiopulmonary bypass; no other procedures for the removal of antibodies were used. Standard immunosuppressive therapy was given, and rejection was monitored by means of endomyocardial biopsy. The results were compared with those in 10 infants who received heart transplants from ABO-compatible donors. RESULTS: The overall survival rate among the 10 recipients with ABO-incompatible donors was 80 percent, with 2 early deaths due to causes presumed to be unrelated to ABO incompatibility. The duration of follow-up ranged from 11 months to 4.6 years. Two infants had serum antibodies to antigens of the donor's blood group before transplantation. No hyperacute rejection occurred; mild humoral rejection was noted at autopsy in one of the infants with antibodies. No morbidity attributable to ABO incompatibility has been observed. Despite the eventual development of antibodies to antigens of the donor's blood group in two infants, no damage to the graft has occurred. Because of the use of ABO-incompatible donors, the mortality rate among infants on the waiting list declined from 58 percent to 7 percent. CONCLUSIONS: ABO-incompatible heart transplantation can be performed safely during infancy before the onset of isohemagglutinin production; this technique thus contributes to a marked reduction in mortality among infants on the waiting list.

ABO Blood-Group System↗
PubMed2001

Comparison of two transcatheter closure methods of persistently patent arterial duct.

A randomized trial of arterial duct occlusion with a double umbrella (DU) or wire coil (WC) was undertaken for patients <18 years of age, weighing >10 kg with isolated ducts < or = 3 mm in diameter. Baseline, procedural, and outcome characteristics were compared in an intention-to-treat analysis according to randomization group. From 40 consecutively screened patients, 2 were not enrolled due to a ductal diameter of >3 mm on initial aortography, 38 patients were randomized to either the DU (n = 20) or WC (n = 18) groups. The groups did not differ significantly with respect to age, weight, gender, duct size, type, or branch pulmonary artery diameters. Crossover occurred only in the DU group, where 4 patients (20%) had a ductal diameter of < or = 1 mm and could not be entered for umbrella placement. All remaining DU group patients had ductal diameters of > or = 1.3 mm (p <0.0001). There were no embolizations or secondary implants in the DU group, but in the WC group there was 1 early and 1 late embolization, with 6 patients (33%) with > or = 2 coils. Mean times for the procedure (DU 68+/-19 minutes; WC 65+/-27 minutes; p = 0.70) and fluoroscopy (DU 14+/-4 minutes; WC 11+/-6 minutes; p = 0.22) did not differ significantly. Angiographic duct closure was documented in 4 of 13 patients (31%) of the DU group and 4 of 18 patients (22%) of the WC group (p = 0.69). Combined with an echocardiogram, closure in 11 of 17 patients with DU (65%) and 13 of 18 patients with WC (72%) (p = 0.64) was documented before hospital discharge. One WC group patient received thrombolytic therapy for a femoral artery thrombus. Follow-up at a median of 6.5 months (range 3.2 to 37) showed closure by Doppler echocardiography in 15 of 19 patients with DU (79%) versus 14 of 18 patients with WC (78%) (p = 1.0). Thus, with a tendency toward similar procedural characteristics and outcomes, the higher cost of the DU system compared with coil implants favors the use of coils for closure of the small arterial duct.

Analysis of Variance↗
PubMed2001

Outcomes of transcatheter embolization in the treatment of coronary artery fistulas.

Thirteen children (seven male) with coronary artery fistula underwent percutaneous transcatheter occlusion. The age range was 8 months to 14 years (mean, 6.3 years). The fistulas had their origins from the right coronary artery (six), from the left anterior descending coronary artery (three), and from the left circumflex coronary artery (four). Drainage was to the right ventricle (seven), the right atrium (three), and one each to the pulmonary artery, left atrium, and superior caval vein. The fistulas were closed with coils in 10 patients, a Rashkind double-umbrella device in 1 patient, and an Amplatzer Duct Occluder in 2 patients. Complete occlusion was achieved in 9 of 13 patients. Complications consisted of migration of coils in four and transient arrhythmias or changes in the resting electrocardiogram in four patients. Follow-up studies 1 to 31 months (mean, 14.6 months) after occlusion noted only four patients with trivial (clinically insignificant) residual shunts. Owing to various coronary fistula morphologies, transcatheter occlusion requires availability of different embolization techniques. Short-term follow-up supports persistent clinical efficacy and transcatheter closure techniques as the initial form of therapy.

Adolescent↗
PubMed2001

Transcatheter creation of an atrial septal defect using radiofrequency perforation.

Transseptal perforation using radiofrequency energy was performed successfully in a patient with congenital heart disease and a thickened interatrial septum. This was followed by balloon dilatation of the atrial septal defect. Radiofrequency is presented as a alternative to standard transseptal needle puncture. Cathet Cardiovasc Intervent 2001;54:83-87.

Catheter Ablation↗
PubMed2001

Total cavopulmonary connections in children with a previous Norwood procedure.

BACKGROUND: Outcomes of the Fontan operation in children initially palliated with the modified Norwood procedure are incompletely defined. METHODS: From August 1993 to January 2000, 45 patients (mean age 2.6 +/- 1.1 years, weight 12.7 +/- 2.8 kg) who were palliated with staged Norwood procedures (hypoplastic left heart syndrome, n = 32; nonhypoplastic left heart syndrome, n = 13) underwent a modified Fontan operation. Preoperative features included moderate/severe atrioventricular valve regurgitation (n = 5, 11%), reduced ventricular function on echocardiography in 11 patients, McGoon index 1.56 +/- 0.38, and pulmonary artery distortion in 18 patients (40%). RESULTS: A lateral tunnel (n = 16) or an extracardiac conduit (n = 29) connection with fenestration in 38 patients (84%) was used. Concomitant procedures included pulmonary artery reconstruction (n = 24, 53%), atrioventricular valve repair (n = 4, 9%) or replacement (n = 1). Before Fontan, 12 patients (27%) had an intervention to address neoaortic obstruction, and 7 patients required balloon dilation/stenting of the left (n = 5) or right pulmonary artery (n = 5). Intraoperatively, left (n = 5) or right pulmonary artery (n = 1) stenting was performed in 5 patients (11%). On follow-up, 8 patients required additional interventional procedures to address left pulmonary artery narrowing (n = 5), or venous (n = 5) or arteriopulmonary collaterals (n = 1). Perioperative mortality was 4.4% (n = 2). There were 2 late deaths at a mean follow-up of 39 +/- 20 months. CONCLUSIONS: In relatively high-risk patients, midterm results of the Fontan operation for children initially palliated with the Norwood procedure were good. Combined interventional-surgical treatment algorithms can lead to improved outcomes.

Child↗
PubMed2001

Chylopericardium after cardiac operations in children.

BACKGROUND: Chylopericardium is a rare complication after operation for congenital heart disease. The incidence and clinical outcomes in a large cohort of surgical patients are unknown. METHODS: We retrospectively reviewed the clinical records spanning more than 12 years in a single institution of 16 children with chylopericardium after cardiac operation. RESULTS: We identified 16 patients with chylopericardium between 1985 and 1997. Chylopericardium was isolated in 7 patients. Twelve patients required pericardial drainage. Patients with isolated chylopericardium presented late and were treated initially as having postpericardiotomy syndrome. Three patients underwent thoracic duct ligation. There were two late deaths unrelated to the chylothorax. Associated diagnoses were internal jugular vein thrombosis and recurrent pulmonary vein obstruction (1 of 16 patients), an associated syndrome but not Turner or Noonan (10 of 16), superior cavopulmonary or total cavopulmonary anastomosis (7 of 16), atrioventricular septal defect repair (5 of 16), and repair of tetralogy of Fallot (2 of 16). CONCLUSIONS: Percutaneous drainage to relieve tamponade together with a low-fat or medium-chain triglyceride diet results in resolution in most cases of postoperative chylopericardium. If a pericardial effusion enlarges, fails to clear on aspirin therapy, or presents late after hospital discharge, diagnostic pericardial tap and a low-fat diet are indicated.

Cause of Death↗
PubMed2001

Evolving strategies and improving outcomes of the modified norwood procedure: a 10-year single-institution experience.

BACKGROUND: This study reviews our 10-year experience with the modified Norwood procedure to determine its early and midterm outcomes. The focus is on the impact of evolving management strategies and accumulated institutional experience. METHODS: A modified Norwood operation was performed in 171 infants over a 10-year period. Sixty-eight percent of the infants were male, the median age at operation was 6 days (range 1 to 175 days), and the median weight was 3.3 kg (range 1.7 to 4.8 kg). The 10-year period was divided into three eras: era I; 1990 through 1993; era II; 1994 through 1997; and era III; 1998 into 2000. Outcomes and risk factors for mortality were sought. RESULTS: Hypoplastic left heart syndrome or a variant was the primary diagnosis in 118 infants (69%). The overall 5-year survival rate was 43%. Multivariate analysis revealed that only need of preoperative ventilatory support, earlier date of operation, and lower weight at operation were significant independent predictors of increased time-related mortality. Morphologic features such as a diagnosis other than hypoplastic left heart syndrome, ascending aortic size, and noncardiac anomalies were not significantly associated with an increased risk of death. The hospital survival rate for stage-one palliation in era III was 82%, significantly better than that in the preceding eras (p < 0.001). Attrition between stages one and two accounted for a 15% mortality rate among hospital survivors. CONCLUSIONS: With increasing experience and improvements in perioperative care and surgical technique, good outcomes can be expected for the first-stage modified Norwood procedure. Greater monitoring of patients in the interstage period may reduce interval mortality and improve overall survival.

Female↗
PubMed2001

Outcomes of intraoperative device closure of muscular ventricular septal defects.

BACKGROUND: The surgical management of muscular ventricular septal defects (mVSD) in the small infant is a challenge particularly when multiple and associated with complex cardiac lesions. Devices for percutaneous implantation have the advantage of ease of placement and for the double umbrella designs a wide area of coverage. We reviewed our experience and clinical outcomes of intraoperative mVSD device closure for such defects in small infants. METHODS: Since October 1989, intraoperative VSD device closure was a component of the surgical strategy in 14 consecutive patient implants (median age, 5.5 months; range, 3 to 11 kg), whose defects were thought difficult to approach using conventional techniques. Nine patients had associated complex cardiac lesions, 10 multiple mVSDs, and 4 patients had a previous pulmonary artery banding. RESULTS: There were 2 early deaths, 1 in a severely ill child who preoperatively had pulmonary hypertension and left ventricular failure and another in a patient with a hypoplastic left heart. Mean pulmonary to systemic flow ratio before device insertion was 3.5:1. Complete closure was achieved in 5 patients and clinically insignificant residual shunts persisted in 7. In 2 infants with significant residual lesions concomitant pulmonary artery banding was required. Postoperative mean pulmonary to systemic flow ratio was 1.7:1. In follow-up of the 12 surviving infants (mean, 41 months), 8 had complete closure and 3 persistent residual shunts. One patient with no residual shunting required heart transplantation for progressive ventricular failure 9 years after operation. All devices were well positioned on postoperative echocardiograms. There was 1 late death due to aspiration in a patient with a tiny residual shunt. CONCLUSIONS: Infants requiring operative intervention with mVSDs are difficult to manage and have an increased mortality and morbidity. Intraoperative VSD device placement for closure of mVSDs is feasible, can avoid ventriculotomy, division of intracardiac muscle bands, and is ideally suited for the neonate or infant.

Echocardiography↗
PubMed2001

Outcomes of transcatheter balloon angioplasty of obstruction in the neo-aortic arch after the Norwood operation.

Obstruction of the reconstructed aortic arch, or the neoaortic arch, is now known to be an important factor increasing mortality after the Norwood operation for hypoplastic left heart syndrome. Transcatheter balloon angioplasty has been shown to provide effective relief of both native aortic coarctation and obstructions of the aortic arch occurring subsequent to therapeutic intervention. We sought to determine the outcomes of balloon angioplasty used as an initial treatment for obstruction of the neoaortic arch occurring after the Norwood operation. We gathered the characteristics of 58 patients with such obstruction from 8 institutions, noting procedural factors and outcomes of initial balloon dilation. Obstruction occurred at a median interval of 4 months, with a range from 1.5 months to 6.3 years, after a Norwood operation. Ventricular dysfunction was present before dilation in 13 patients. Mean peak to peak systolic pressure gradients were acutely reduced from 31+/-20 mm Hg to 6+/-9 mmHg (p<0.001), with outcome subjectively judged to be successful in 89%. Three patients with pre-existing ventricular dysfunction died within 48 hours of dilation. There were 10 additional deaths during the period of follow-up, with Kaplan Meier estimates of survival after intervention of 87% at 1 month, 77% at 12 months, and 72% after 15 months. In addition, 9 patients required re-intervention during the period of follow-up, with Kaplan Meier estimates of freedom from re-intervention after dilation of 87% at 6 months, 78% at 12 months and 74% after 18 months. Although transcatheter dilation of neoaortic arch obstructions after Norwood operation is successful, there is a high risk of re-intervention and ongoing mortality in this subgroup of patients. Close follow-up is recommended.

Angioplasty, Balloon↗