Search PubMed⌕ Search

Biomedical subjects

L N Benson

Publications and source records attributed to L N Benson.

At least 73 records · Page 4Linked to original sources
PubMed1997

Coil embolization of a coronary artery to pulmonary artery fistula from an antegrade approach.

Transcatheter embolization of coronary artery fistulae has become the therapy of choice for this uncommon lesion. We report a case in which transcatheter embolization was performed in a nine-year-old boy with a large fistula originating from the proximal portion of the left anterior descending artery and communicating with the pulmonary artery and the right coronary artery. The fistula was occluded 'antegrade' by cannulating the connection with the pulmonary artery to deliver occluding coils.

Arterio-Arterial Fistula↗
PubMed1997

Cardiomyopathy: a late complication of hemolytic uremic syndrome.

This report describes a child who presented with classic hemolytic uremic syndrome (HUS) and 4 months later developed a life-threatening but reversible cardiomyopathy with global cardiac dysfunction and a left ventricular ejection fraction of 14%. There was no evidence of electrolyte abnormalities, anemia, hypertension, severe fluid overload, or viral infection. Endomyocardial biopsies were consistent with a dilated cardiomyopathy. This paper highlights the importance of considering the diagnosis of associated cardiomyopathy when presenting with late-onset edema following HUS.

Cardiomyopathies↗
PubMed1997

The modified Blalock-Taussig shunt: clinical impact and morbidity in Fallot's tetralogy in the current era.

BACKGROUND: The Blalock-Taussig shunt is considered a low-risk management option for palliation in tetralogy of Fallot, but the morbidity associated with a Blalock-Taussig shunt can have a significant impact on patient care. We reviewed the outcome for this operation in the current era. METHODS: Between 1990 and 1994, 65 children with tetralogy of Fallot received a modified Blalock-Taussig shunt. Sixty patients who had follow-up angiography were assessed for clinical outcomes and shunt-related morbidity and mortality. From the same study period, 68 of 247 pediatric patients who underwent angiography and tetralogy repair, but did not receive palliation, were randomly selected to comprise a comparison group. RESULTS: Palliation was more likely in the presence of a complicated tetralogy malformation or if there was an associated medical condition. Median age at palliation was 58 days (range: 1 to 535 days). Ninety-five percent of shunts were right-sided. Self-limited morbidity complicated 11% of shunt operations. Significantly smaller distal right pulmonary arteries were observed in the palliated group before total repair compared with findings in the group without palliation and 33% of patients who underwent palliation had angiographic evidence of pulmonary artery distortion. Shunt stenosis was common and correlated with younger age at palliation. Shunt occlusion resulted in one death. Excluding noncardiac causes of death, overall survival was 90% in the palliated group versus 97% in the nonpalliated group (p = 0.09). CONCLUSIONS: Pulmonary artery hypoplasia and angiographic evidence of pulmonary artery distortion are common after initial palliation by a modified Blalock-Taussig shunt. Neonatal palliation was associated with significantly smaller pulmonary arteries before repair, which necessitated additional interventions.

Anastomosis, Surgical↗
PubMed1997

Balloon dilation of severe aortic stenosis in the neonate: comparison of anterograde and retrograde catheter approaches.

OBJECTIVES: We sought to compare anterograde and retrograde balloon dilation of severe aortic valve stenosis in neonates. BACKGROUND: There is a high incidence of iliofemoral artery complications after retrograde balloon dilation of the aortic valve in the neonate. Therefore, a nonarterial technique of catheter access to the aortic valve would be worth exploring. METHODS: Group 1 included 11 consecutive patients (median age 6 days, range 1 to 42; median weight 3.5 kg, range 2.16 to 4.25) undergoing attempted anterograde dilation through a femoral venous approach. Group 2 included 15 patients (median age 3 days, range 1 to 35; median weight 3.4 kg, range 2.5 to 4.4 kg) who underwent attempted retrograde dilation, including 2 in whom attempted anterograde approach had failed. RESULTS: The valve was successfully crossed in 9 of 11 anterograde and 13 of 15 retrograde dilations. In both groups, the peak gradient across the valve decreased significantly (both p = 0.001). On echocardiography, the jet width of the aortic incompetence/ annulus diameter ratio was 0.16 +/- 0.08 (mean +/- SD) after anterograde and 0.51 +/- 0.24 after retrograde dilation (p = 0.03), possibly because of unrecognized valve leaflet perforation. Two patients in group 1 developed persistent, mild mitral insufficiency. Femoral artery thrombosis developed in one patient after anterograde dilation and in eight after retrograde dilation (p = 0.03). CONCLUSIONS: This series demonstrates that an anterograde approach for balloon angioplasty of severe neonatal aortic valve stenosis is feasible, achieves good hemodynamic relief and lessens morbidity compared with retrograde arterial techniques.

Age Factors↗
PubMed1996

Aortic valve regurgitation after surgical versus percutaneous balloon valvotomy for congenital aortic valve stenosis.

To compare characteristics of aortic regurgitation (AR), the results of 213 procedures (110 balloon aortic valvotomies [BAV] and 103 surgical aortic valvotomies [SAV]) for treatment of congenital aortic valve stenosis were reviewed. These procedures were performed in 187 patients from June 1981 to September 1993. Echocardiograms recorded immediately before, within 6 months afterward, and at latest follow-up were compared. Color Doppler was used to assess the degree of AR and was quantified as the ratio of the regurgitant jet width to valve annulus, the jet width ratio. Whereas BAV patients were older (median age 5.7 years vs 3 months; p = 0.0001), there was no significant difference in median follow-up interval (3.1 years [range 0.5 to 7.2] for BAV vs 3.6 years [range 0.6 to 10.4] for SAV; p = 0.44). The mean balloon-to-annulus ratio for BAV was 0.99 +/- 0.09. An open valvotomy was performed in 83% of surgical cases. Acute systolic gradient reduction and subsequent increase at late follow-up was similar for both groups. Acutely, the mean jet width ratio increased similarly (p = 0.84) for BAV (+9 +/- 15%; p = 0.0001) and SAV (+9 +/- 12%; p = 0.0003) and was not related to age at procedure. At late follow-up, mean jet width ratio further increased significantly in both groups, although there was no difference (p = 0.17) in amount of progression (BAV +10 +/- 12%; p = 0.0001, SAV +15 +/- 13%; p = 0.0002). Thus, BAV and SAV produce AR of similar severity with similar rates of progression.

Aortic Valve↗
PubMed1996

Percutaneous catheter closure of the persistently patent ductus arteriosus in the adult.

The USCI patent ductus occluder has been shown to be an effective nonsurgical technique for closure of the persistently patent ductus in a primarily pediatric population. Its clinical impact in the adult has been reported only within small subgroups of larger pediatric studies or for a small population. This study was conducted to determine the feasibility, success rate, and complications of device closure for the persistently patent ductus arteriosus (PDA) in the adult. The population consisted of 55 patients (4 men and 51 women; mean age 38.8 +/- 15.0 years) with follow-up of 2.2 +/- 2.1 years. All patients underwent echocardiography obtained as part of their follow-up assessment. The device was successfully placed in 54 patients, with 75% clinical and echocardiographic closure at the first follow-up assessment 2.4 +/- 2.6 months). One patient with initial clinical and echocardiographic evidence of closure was subsequently found to have an open ductus. Spontaneous closure (2 patients) or second implant (6 patients) resulted in 86% closure at the most recent assessment. Thus, the percutaneous PDA double-umbrella occluder device is a feasible and effective technique for closing persistent PDA in the adult and will result in occlusion of the shunt in most patients without the need for thoracotomy.

Adolescent↗
PubMed1996

Unraveling of a Gianturco coil during reocclusion of a patent ductus arteriosus.

The Gianturco spring coil has been employed in the settling of the small arterial duct and for reocclusion of residual shunts; the ability to manipulate the coil is advantageous for optimal results. This case study reports an associated complication of unraveling of the coil. Careful attention to coil appearance during manipulation and the use of 0.038-inch coils may reduce this risk.

Child, Preschool↗
PubMed1996

Morphologic and hemodynamic consequences after percutaneous balloon valvotomy for neonatal pulmonary stenosis: medium-term follow-up.

OBJECTIVES: This study sought to evaluate ventricular and valvular morphologic changes, hemodynamic consequences and clinical outcomes of pulmonary balloon valvotomy performed in the neonatal period. BACKGROUND: Previous studies support percutaneous balloon valvotomy as the management option of choice for infants and children with valvular pulmonary stenosis. Less information is available to define the impact of valvotomy on the clinical course when performed in the neonatal period. METHODS: Patient records, catheterization data, cineangiograms and selected echocardiograms (initial and most recent studies) of 37 consecutive neonates undergoing attempted balloon dilation were reviewed. RESULTS: Dilation was accomplished in 35 (94%) of 37 attempts. Immediately after dilation, the transvalvular peak to peak systolic gradient decreased from 60 +/- 22 mm Hg (mean +/- SD, range 20 to 100) to 11 +/- 10 mm Hg (range 0 to 45) (p < 0.0001), and the right ventricular/aortic systolic pressure ratio decreased from 1.25 +/- 0.43 (range 0.5 to 2.6) to 0.66 +/- 0.22 (range 0.2 to 1) (p < 0.0001). Oxygen saturation measured by percutaneous oximetry increased from 80 +/- 7% to 92 +/- 4% (p < 0.0001). Three patients died (8%), and two required repeat balloon dilation. At the follow-up visit (median 31 months, range 6 months to 8 years), the estimated peak instantaneous Doppler gradient was 15 +/- 9 mm Hg (range 6 to 36). Thickening of valve leaflets, initially present in 93% of patients, was found in only 4%, and leaflet mobility improved in all. Hypoplasia of the right ventricle, initially present in 31%, was found in only 4% at the latest evaluation. Pulmonary annulus diameter Z score increased from -3 +/- 1.0 to 0 +/- 0.1 (p < 0.0001). Freedom from reintervention was 90%, 84% and 84% at 1, 2 and 8 years, respectively. CONCLUSIONS: These data support the application of balloon valvotomy as the initial intervention in the treatment algorithm for neonates with critical pulmonary valve stenosis. Medium-term follow-up observations demonstrate sustained hemodynamic relief and support maturation of the right ventricle and pulmonary valve annulus, with the expectation of a good long-term outcome.

Algorithms↗
PubMed1996

Augmentation of pulmonary blood flow with an axillary arteriovenous fistula after a cavopulmonary shunt.

Of 320 children with cyanotic congenital heart malformations who had previously undergone cavopulmonary shunt operations, 11 had increasing cyanosis and exercise intolerance and were considered unsuitable for definitive repair, a Fontan procedure, or other palliation. Eight had a previous Glenn shunt and three had a previous bidirectional cavopulmonary connection. To augment pulmonary blood flow, 10 patients underwent creation of an ipsilateral axillary arteriovenous fistula. Mean oxygen saturations were 80% +/- 2% before operation, 85% +/- 2% immediately after operation, and 84% +/- 3% at a mean follow-up interval of 7.4 years (range 0.1 to 15.5 years). Mean hemoglobin values were 202 +/- 10 gm/L before operation, 177 +/- 10 gm/L after operation, and 191 +/- 14 gm/L at latest review. The only complication was mild swelling of the arm distal to the fistula in one patient. All patients reported improvement in exercise tolerance. Eight patients have continued evidence of fistula patency. Development of ipsilateral pulmonary arteriovenous fistulas has not been observed in any patient. Creation of an axillary arteriovenous fistula to augment pulmonary blood flow after a cavopulmonary shunt provides useful palliation for complex cyanotic heart disease when other options are limited. Such additional sources of pulmonary blood flow may influence the development of pulmonary arteriovenous fistulas.

Arteriovenous Shunt, Surgical↗
PubMed1995

Endovascular stents in the pulmonary circulation. Clinical impact on management and medium-term follow-up.

BACKGROUND: The use of endovascular stents to relieve obstructions in the setting of non-balloon dilatable pulmonary artery stenosis has been encouraging. The benefits in management and the potential for restenosis, however, have not been defined. This study attempts to assess the impact of such implants on clinical outcomes and the pattern of stent incorporation within the vessel wall. METHODS AND RESULTS: Fifty-five balloon-expandable stents were implanted in 42 patients 6.1 +/- 4.7 years of age. Patients were followed prospectively (median, 15 months) and recatheterized 1 year after implantation. Thirty-eight patients had the implants positioned percutaneously (49 implants), while 4 patients (6 implants) had intraoperative implantations. There was a diameter increase in the stenotic area of 109 +/- 79% (P < .0001) and a gradient reduction of 74 +/- 26% (P < .0001). Twelve stents straddled the orifice of side-branch pulmonary arteries and reduced flow to the branch vessel acutely in 7 patients. Twenty-nine patients underwent recatheterization, and various degrees and locations of acquired intraluminal narrowing were observed in all cases, particularly in areas of diameter mismatch between the stented and nonstented vessels. Eleven patients had further dilation with diameter improvement. Of the 38 patients who underwent percutaneous implantation, planned surgery for pulmonary artery stenosis was avoided in 33 and deferred in 4 patients. One patient who was considered inoperable had stent implantation as a palliative procedure. Symptomatic improvement was reported in 27 patients, and 15 patients remained asymptomatic. CONCLUSIONS: Endovascular stents have a role in the treatment of pulmonary artery stenoses and positively affect clinical care. The stenosis relief, however, may be tempered by the development of intraluminal stent obstruction, which may require redilation (15 of 55 stents) and mandates long-term follow-up.

Adolescent↗
PubMed1995

Stenting for pulmonary artery stenosis following the Ross procedure.

A 34-year-old woman showed the development of significant main pulmonary artery obstruction along the supravalvar suture line 18 months following a Ross procedure. The patient underwent unsuccessful balloon angioplasty, followed by successful stent implantation. The angiographic narrowing disappeared postprocedure, and the excellent hemodynamic result maintained at 4 month follow-up.

Adult↗
PubMed1995

Experience with repair of congenital heart defects using adjunctive endovascular devices.

The use of endovascular devices as an adjunct to repair of congenital heart anomalies represents a novel but unproven therapeutic approach. Intraoperative implantation of pulmonary arterial stents (5 to 15 mm diameter) was done in 11 patients with pulmonary atresia with ventricular septal defect (n = 4), classic tetralogy of Fallot (n = 2), truncus arteriosus (n = 1), hypoplastic left heart syndrome (stage II [n = 1] and stage III [n = 1] Norwood procedure), and miscellaneous pulmonary arterial stenoses (n = 3), as well as in patients with congenital (n = 1) and postoperative (n = 3) pulmonary venous obstruction and in 1 patient with combined pulmonary arterial and venous obstruction. The stents were effective at achieving immediate patency in all patients. There were two early deaths, one related to acute thrombosis of a small-diameter left pulmonary artery stent. Reintervention because of stent-related pulmonary arterial stenosis was frequently necessary. In five of seven patients who survived more than 1 month after implantation of stent size 8 mm or smaller severe stent-related pulmonary arterial obstruction developed. In four of the five patients with pulmonary vein stent implantation intractable obstruction developed, resulting in death in all three patients who had bilateral pulmonary vein stent implantation. Intraoperative occlusion of apical muscular ventricular septal defect with use of a clamshell device inserted from the right atrial approach was accomplished in four patients. One patient who underwent associated aortic arch reconstruction died as a result of left ventricular hypoplasia. The results in the remaining three patients were favorable on the basis of absence of significant late residual intraventricular shunting, left ventricular dysfunction, or arrhythmia. We conclude that recurrent intraluminal obstruction as a result of neointimal hyperplasia appears to be an eventual certainty in currently designed small-diameter endovascular stents. For this reason, we would recommend standard surgical techniques for repair of obstructive lesions of the pulmonary arterial confluence to maximize growth potential. Device occlusion of muscular ventricular septal defects is feasible but probably only indicated for complex cases of ventricular septal deficiency that otherwise necessitate a left ventriculotomy.

Adolescent↗
PubMed1995

Endovascular stents in pediatric cardiovascular medicine.

Acquired or de novo vascular obstructions can adversely affect the outcomes of management algorithms for children with congenital heart lesions. Although surgical repair is frequently feasible, some acquired or congenital obstructions are difficult to address in the operating theater. Discussed is the recent experience with endovascular stents to relieve such stenoses, and their impact on patient care.

Animals↗
PubMed1995

Right to left interatrial communications after the modified Fontan procedure: identification and management with transcatheter occlusion.

OBJECTIVE: To describe unusual venous communications from the right to the left atrium resulting in cyanosis after the modified Fontan procedure, and their management with transcatheter occlusion. METHODS: Between September 1992 and November 1994, eight patients were assessed for persistent cyanosis after a modified Fontan procedure. Desaturation was found to be caused by unusual venous shunts originating at atrial level, and transcatheter occlusion with either a double umbrella or coil was attempted. RESULTS: Three types of venous channels were identified. The first type of communication consisted of thin long tortuous channels originating from the right atrial wall, and draining into the left atrium through a capillary network. The second type of communication was in the superior anterior portion of the atrial baffle, incorporating the pectinate muscles of the right atrium, draining into the neoleft atrium. These channels were shorter and often fanned out into small vessels toward the right atrial appendage. In each instance, the shunts were in the superior suture line of a lateral tunnel modification of the Fontan procedure. The third type of communication originated from the inferior vena cava, connecting inferior phrenic veins to pericardial veins and subsequently to the left atrium, at or close to the ostium of the left pulmonary veins. Before device occlusion, the room air aortic oxygen saturation was 88(SD 4)% (range 84% to 94%), and increased to 95(3)% (range 91% to 100%) following occlusion (PL << 0.001). The mean right atrial pressure was 14(4)mm Hg and remained unchanged after occlusion. In six patients there was complete shunt obliteration, while in two both occluded with umbrella devices, a small residual leak persisted. No complication occurred during or immediately after catheterisation. CONCLUSIONS: Unusual venous communications can evolve after the Fontan procedure, resulting in the development or persistence of cyanosis. Some of these communications may be present preoperatively as normal veins draining into the right atrium, enlarging with the increased atrial pressure after surgery. These observations affect long term function after the Fontan procedure. Transcatheter occlusion of these communications is technically feasible and effective, although recurrence may occur.

Adolescent↗
PubMed1995

Endovascular stents in children under 1 year of age: acute impact and late results.

OBJECTIVES: To review efficacy and safety of endovascular stent implants in children < 1 year of age with congenital heart lesions. DESIGN: Retrospective study of patients in a tertiary care setting. PATIENTS: 26 children (median age of 4.7 months, range 2 days to 1 year) with various vascular obstructive lesions. INTERVENTION: Percutaneous or intraoperative implantation of balloon expandable endovascular stents. RESULTS: Optimal stent placement was obtained in 31 of the 37 deployed implants. Complications resulted primarily from stent malpositioning and one episode of bleeding at a puncture site. Stent implantation in three patients with a restrictive arterial duct allowed for patency and five patients with conduit stenosis had mean (SD) right ventricule to systemic artery pressure ratios falling from 0.99 (0.20) to 0.52 (0.18) (P < 0.05). In 10 patients with pulmonary artery stenosis, the mean vessel diameter increased from 2.8 (0.9) mm to 5.8 (1.4) mm (P << 0.001). No clinical improvement was seen in two patients because of diffuse hypoplasia of the pulmonary vessels. Nine of 10 patients with miscellaneous obstructive lesions improved clinically. Recatheterisation was performed in 19 patients (median 8 months, range 12 days to 28 months) and 11 patients required redilatation (17 stents). CONCLUSIONS: Stent implantation is technically feasible in infants and under specific circumstances may provide an alternative to surgical palliation or avoid reoperation. The long term impact on clinical course, however, involves further interventions directed at stent management.

Arterial Occlusive Diseases↗
PubMed1995

Measurement of right ventricular volume by conductance catheter in closed-chest pigs.

This study details the effects of changes in right ventricular (RV) volume on the conductance catheter gain factor both over a broad volume range and within the cardiac cycle. In seven closed-chest anesthetized pigs, a conductance catheter was introduced transvenously and positioned to span the RV long axis, including the outflow tract. Parallel conductance was determined using a saline dilution technique. Conductance volume gain factor (alpha) was computed using stroke volume obtained by thermodilution over a range of volumes obtained by volume loading or sustained partial occlusion of the inferior caval vein. The chest was then opened, an ultrasonic flow probe was placed around the pulmonary artery, and the conductance-derived RV volume was compared with the pulmonary flow integral over the course of ejection. When volume was varied over a broad range, an inverse relation between RV volume and alpha was observed (P < 0.001). This did not cause significant nonlinearity of the conductance-volume relation. The relation was also relatively linear during the course of ejection within the cardiac cycle. These results indicate that the conductance catheter may be employed, using the described technique, to assess RV volume under steady-state conditions.

Animals↗