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Lee N Benson

Publications and source records attributed to Lee N Benson.

At least 19 recordsLinked to original sources
PubMed2006

Cardiac perforation 6 weeks after percutaneous atrial septal defect repair using an Amplatzer septal occluder.

A 14-year-old boy presented to the emergency department unaccompanied by his parents with a decreased level of consciousness, bradycardia, and hypotension after a syncopal episode. The patient's electronic chart revealed a percutaneous closure of a secundum atrial septal defect using an Amplatzer septal occluder (AGA Medical, Golden Valley, MN) 6 weeks before this presentation. An urgent echocardiogram revealed a moderate pericardial effusion, and 320 mL of fresh blood was evacuated by subxiphoid pericardiocentesis. The child underwent surgical exploration and was found to have a perforation in the superior-posterior aspect of the right atrium, which was corrected. The septal occluder was extracted, and the atrial septal defect was closed with a pericardial patch. This case illustrates a rare but life-threatening complication of percutaneous closure of atrial septal defect using an Amplatzer septal occluder and the importance of timely access to patient records when available history and physical examination are limited.

Adolescent↗
PubMed2006

Transcatheter device versus surgical closure of ventricular septal defects: a clinical decision analysis.

OBJECTIVES: To compare transcatheter device versus surgical closure of ventricular septal defects (VSDs). METHODS: A clinical decision analysis was performed using standard gamble interviews. RESULTS: Device was initially preferred in 39 respondents (89%) and surgery in 5 (11%). The inherent difference in value between a perfect surgery and a perfect device (disutility of surgery) was equal to a mean risk of death of (1.2 +/- 2.2)%. Final values from decision analysis were initially equivalent. Values adjusted for estimated mortality, however, favored device (mean: 0.979 +/- 0.032) versus surgery (mean: 0.971 +/- 0.032), P = 0.052. When values were further adjusted for disutilities, device was significantly preferred (0.978 +/- 0.032) versus surgery (0.961 +/- 0.044), P < 0.005. Surgery would be preferred if the probability of major complications decreased below 5% or minor complications below 6%. CONCLUSIONS: When outcomes and their values are considered in a systematic manner, transcatheter device closure of suitable VSDs is favored over surgical repair.

Attitude of Health Personnel↗
PubMed2006

Presentation, management and outcomes of thrombosis for children with cardiomyopathy.

BACKGROUND: Thrombosis in children with dilated and inflammatory cardiomyopathy is an unpredictable complication with potentially important morbidity. OBJECTIVE: To determine the prevalence, associated factors, management and outcomes of thrombosis in this setting. METHODS: Data were obtained from review of medical records. Factors associated with thrombosis and the impact on outcome were sought. RESULTS: From 1990 to 1998, 66 patients that presented with dilated cardiomyopathy were followed for a median interval of 1.4 years (range 0 to 9.79 years) from first presentation. Thrombosis was diagnosed in four patients at presentation and in four patients during follow-up. Thrombosis was noted in one additional patient at examination after death. The overall nine-year period prevalence of thrombosis was 14%. Anticoagulation was started at presentation in 31% of patients. The mean left ventricular ejection fraction at presentation was significantly lower in those given anticoagulation (19+/-8%) versus those who were not (32+/-15%; P < 0.001). The mean ejection fraction at presentation was similar in those patients with (25+/-10%) versus those without thrombosis (28+/-15%; P = 0.44). During follow-up, 11 patients died and seven underwent cardiac transplantation. Kaplan-Meier estimates of freedom from death or transplantation were 88% at three months, 81% at one year and 70% at five years. Survival free of transplantation was not affected by thrombosis. CONCLUSIONS: Thrombosis is common in children with cardiomyopathy, can occur at any time in the patients' clinical course and is not related to clinical features or survival free of transplantation. The relevance and prevention of thrombosis in this setting remains unclear.

Adolescent↗
PubMed2005

Gene transfer of prostaglandin synthase maintains patency of the newborn lamb arterial duct.

In congenital heart disease with left- or right-sided obstruction, prostaglandin E (PGE)1 or PGE2 is infused to maintain ductus arteriosus (DA) patency. We hypothesized that transfection of the DA with PGE synthase would lead to a greater production of PGE2 in situ and, hence, patency of the DA. The cDNA for human prostaglandin synthase was sequenced and ligated into a eukaryotic expression vector. The negative control was created by ligating the cDNA encoding the bacterial protein chloramphenicol acetyltransferase into the same plasmid. Transfection (600 microg DNA) was achieved in lambs within the first 24 h of life using the hemagglutinating virus of Japan (HVJ)-liposome transfection method with a custom-made, basket-weave-perforated catheter. Echocardiography was performed to assess DA patency until the time of sacrifice. To confirm expression of the transgene, PGE2 concentration was measured in organ culture of the DA by immunoassay and by Western immunoblotting of homogenized DA tissue. Patency of the DA was demonstrated by color Doppler in all the lambs (7/7) in which the PGE synthase was delivered, whereas functional closure was seen in the control group (6/6). The PGE2 concentration in the culture medium of the explanted DA in the treatment group was 3-fold higher than that of the control groups. Western immunoblotting confirmed the presence of PGE synthase in the treatment group. Gene transfer of PGE synthase to the DA is feasible and will maintain patency for at least 1 wk.

Animals↗
PubMed2005

How is pulmonary arterial blood flow affected by pulmonary venous obstruction in children? A phase-contrast magnetic resonance study.

BACKGROUND: Hemodynamic changes within a stenosed pulmonary vein might not reflect the severity of the obstruction if redistribution of pulmonary artery flow occurs. OBJECTIVE: The purpose was to investigate flow changes in branch pulmonary arteries in the presence of pulmonary vein stenosis. MATERIALS AND METHODS: Twelve children (age range 3-180 months) who had undergone MRI for pulmonary vein stenosis were identified. The severity of vein stenosis was assessed from percentage diameter reduction. Pulmonary artery flow distribution was correlated with the severity of pulmonary vein stenosis. Nine of the patients had unilateral stenosis; three had bilateral involvement. RESULTS: Unilateral vein stenosis was associated with diastolic reversal in the ipsilateral branch pulmonary artery (mean flow reversal 12.3%, range 2.4-42%) and continuous diastolic forward flow in the contralateral pulmonary artery in seven of nine patients. Severe stenosis was associated with decreased systolic flow to the ipsilateral lung. The ratio of net forward flow through pulmonary arteries correlated well with the cross-sectional area ratio of pulmonary arteries (r=0.75, P=0.006). CONCLUSIONS: Severe pulmonary vein obstruction results in redistribution of pulmonary arterial flow. When investigating pulmonary vein stenosis by MR, an evaluation of the pulmonary arterial system should be included to assess the functional importance of an obstruction.

Adolescent↗
PubMed2005

Transcatheter closure of atrial septal defects in children with a hypoplastic right ventricle.

The efficacy and safety of device closure of atrial defects in children with complex congenital heart disease and a hypoplastic right ventricle have not been detailed. The objective of this study was to determine the clinical impact and outcomes of a staged surgical catheter-based management strategy. A retrospective analysis of 17 children with a hypoplastic right ventricle who had undergone cardiac catheterization and attempted device occlusion of an atrial defect was undertaken. Clinical data, anatomical diagnoses, previous surgeries, and interventions were noted. The clinical course and echocardiographic findings were compared before and after defect closure (6 +/- 4 months of follow-up). Nine children had pulmonary atresia with an intact ventricular septum, six had Ebstein's anomaly of the tricuspid valve, and two had isolated right ventricular hypoplasia. The mean age at defect closure was 6.6 +/- 3.4 years. Under general anesthesia, closure of the atrial defect was undertaken after initial temporary test occlusion. The Qp:Qs ratio before closure was 1.1 +/- 0.4. Oxygen saturation improved in all children from 91% +/- 1% to 98% +/- 1% (P < 0.0005). Mean right atrial pressure increased from 9 +/- 3 to 11 +/- 4 mm Hg after closure, but the difference was not statistically significant (P = 0.2). Follow-up revealed an increased right ventricular length (P = 0.009) and Z-score (P = 0.02), although no significant increase in the diameter of the tricuspid valve annulus was observed in children with pulmonary atresia. Right ventricular systolic pressures or systolic function did not change significantly during follow-up (P = 0.5 and 0.29, respectively). Exercise tolerance improved in all children and clinical evidence of right ventricular decompensation was absent. Catheter closure of atrial defects in children with a hypoplastic right ventricle is well tolerated, safe, and effective as a treatment strategy in the staged management.

Cardiac Catheterization↗
PubMed2005

Radiofrequency perforation and conventional needle percutaneous transseptal left heart access: pathological features.

Perforating radiofrequency (PRF) energy has been used to obtain percutaneous transseptal left heart access. Contrary to ablative radiofrequency (RF), myocardial tissue responses to PRF thermal injury are incompletely defined. In this study, a newly developed RF catheter system for transseptal left atrial entry was compared with conventional needle puncture. Of 15 piglets having transfemoral cardiac catheterization, 12 had transseptal procedures. Needle punctures (NP) and PRF were followed by acute (1 hr; 3 NP, 3 PRF) and chronic necropsy (1 month; 3 NP, 3 PRF). The remaining three piglets had intentional RF aortic perforation through the atrial roof with necropsy at 1 month. Gross and histopathological effects were examined. Acutely, the gross RF lesion was similar to needle puncture. Histologically, the RF lesions had minimal mural thrombus, an inner zone of thermal injury characterized by grayish cytoplasmic staining (elastic trichrome), and a bubbly transformation of the cytoplasm in innermost cardiomyocytes, partial persistence of cross-striations, and an acute inflammatory reaction. The outer extent of the lesion (< 1 mm) was defined by a halo of contraction band necrosis similar to needle puncture. Acute NP injury showed comparable depth and extent of myocyte necrosis (principally contraction bands) with adjacent tissue hemorrhage and edema. At 1 month, a well-developed densely collagenous scar was present in both aortic and transseptal PRF lesions. The extent of acute RF injury is similar to that seen in conventional NP, but the characteristics of tissue insult are different. Both show well-developed healing at 1 month.

Animals↗
PubMed2005

Hemodynamic evaluation of the peripheral pulmonary circulation by cine phase-contrast magnetic resonance imaging.

PURPOSE: To describe the normal flow patterns in peripheral pulmonary vessels with phase-contrast (PC) magnetic resonance imaging (MRI). MATERIALS AND METHODS: Twelve healthy adults (age = 33 +/- 7 years) underwent cine PC MRI of the segmental and central pulmonary arteries and veins by means of a breath-held segmented k-space technique. Flow patterns were analyzed on time-velocity curves and compared between the peripheral and central vessels. RESULTS: The pulsatile flow patterns in the segmental arteries and veins were similar among individuals. When compared with the central pulmonary arteries, the segmental arteries had a delay in the systolic and diastolic flow velocity waves, and an increased magnitude of the diastolic peaks, in relation to the systolic peaks. A prominent notch was present during the deceleration phase of the systolic flow velocity wave in 79% of the segmental arteries investigated. The segmental veins showed a typical pulmonary venous flow pattern, as seen in the central veins, with similar systolic-to-diastolic peak velocity ratios. CONCLUSION: Noninvasive evaluation of blood flow in intraparenchymal pulmonary vessels is feasible with PC MRI. This first description of normal flow patterns in segmental pulmonary arteries and veins can serve as basis for further investigation in the setting of altered pulmonary blood flows.

Adult↗
PubMed2005

Clopidogrel use in children.

OBJECTIVES: To review a pediatric experience with the antiplatelet agent clopidogrel and suggest a dosage regimen. STUDY DESIGN: A retrospective chart review of all infants and children treated with clopidogrel at The Hospital for Sick Children, Toronto between January 2001 and April 2004. Clopidogrel dosages, duration of therapy, complications, and adverse effects in a pediatric population were explored. RESULTS: Fifteen infants and children with congenital and acquired heart disease were treated with clopidogrel (median age, 3.5 years; range, 6 weeks to 16 years). Dosages ranged from 1 to 6 mg/kg/day for periods between 1 month and 6 months. Although no thrombotic events were reported, 1 child had a bleeding complication (gastrointestinal) while on triple antithrombotic therapy. Other complications reported in adults, including rash and clinical thrombocytopenia, were not noted in this pediatric series. CONCLUSIONS: Clopidogrel was well tolerated. We suggest a starting dose of 1 mg/kg/day for children.

Adolescent↗
PubMed2005

Neonatal aortic stenosis.

Neonatal aortic stenosis is a complex and heterogeneous condition, defined as left ventricular outflow tract obstruction at valvular level, presenting and often requiring treatment in the first month of life. Initial presentation may be catastrophic, necessitating hemodynamic, respiratory and metabolic resuscitation. Subsequent management is focused on maintaining systemic blood flow, either via a univentricular Norwood palliation or a biventricular route, in which the effective aortic valve area is increased by balloon dilation or surgical valvotomy. In infants with aortic annular hypoplasia but adequately sized left ventricle, the Ross-Konno procedure is also an attractive option. Outcomes after biventricular management have improved in recent years as a consequence of better patient selection, perioperative management and advances in catheter technology. Exciting new developments are likely to significantly modify the natural history of this disorder, including fetal intervention for the salvage of the hypoplastic left ventricle; 3D echocardiography providing better definition of valve morphology and aiding patient selection for a surgical or catheter-based intervention; and new transcutaneous approaches, such as duel beam echo, to perforate the valve.

Aorta↗
PubMed2004

Stenting the neonatal arterial duct in duct-dependent pulmonary circulation: new techniques, better results.

OBJECTIVES: The goal of this study was to assess a new approach to stent the arterial duct in neonates with a duct-dependent pulmonary circulation. BACKGROUND: Previous attempts to stent the neonatal arterial duct were unsatisfactory. Learning from these failures, we speculated that covering the complete length of the duct with current low-profile stents might avoid previous problems. METHODS: Ten neonates with duct-dependent pulmonary circulations through a short straight duct were treated with stent implantation. The duct was crossed with an atraumatic 0.014-inch wire. A low-profile premounted coronary stent (outer diameter <4F, length 13 to 24 mm, diameter 3.0 to 4.0 mm) was positioned within the duct, not protected by a sheath; care was taken to cover the complete length of the duct from the aortaductal junction until well within the pulmonary trunk. RESULTS: All stents could safely be deployed with adequate pulmonary flow at early- and medium-term follow-up. There were no procedure-related complications; one patient died early from sepsis. All patients had adequate relief of cyanosis for at least three to four months. During follow-up, the pulmonary vasculature bed had grown without distortion. Acute occlusion of a stented duct was not observed. Ductal flow progressively decreased slowly over several months by luminal narrowing, until the stented duct had either become redundant or was dilated/restented or until elective staged surgery was performed. CONCLUSIONS: With current technology, complete stenting of a short straight duct is a safe and effective palliation, allowing adequate growth of the pulmonary arteries.

Cardiac Surgical Procedures↗