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Biomedical subjects

L N Benson

Publications and source records attributed to L N Benson.

At least 127 records · Page 7Linked to original sources
PubMed1991

Assessment of myocardial perfusion in patients after the arterial switch operation.

In 21 patients who had undergone the arterial switch operation, the adequacy of myocardial perfusion was evaluated by thallium-201 computed scintigraphy 2.6 +/- 2 (0.3-7) yr after surgery. Fourteen patients had undergone the arterial switch procedure after pulmonary artery banding and seven as a primary repair. Isoproterenol stress increased the heart rate by at least 55%. Tomographic imaging was performed at peak stress and 3 hr later in the reperfusion phase. Nine patients had perfusion defects. The perfusion defects were located at the left ventricular apex in four (with extension to the inferolateral wall in one), left ventricular anterolateral wall in two, ventricular septum in one, left ventricular inferior wall in one, and right ventricular free wall in one. Some of these defects could be due to myocardial damage at the time of surgery, but these results also raise concern about long-term adequacy of myocardial perfusion following the arterial switch procedure.

Child↗
PubMed1990

Management of neonatal critical pulmonic stenosis in the balloon valvotomy era.

We evaluated our recent experience with management of neonatal critical pulmonic stenosis and intact ventricular septum between 1982 and 1988. Thirty-nine patients (aged less than 3 months) were treated initially by operation (group A, n = 19) or with balloon pulmonary valvotomy (group B, n = 20). Patients in group A were younger (5 +/- 1.3 versus 18 +/- 4 days in group B) (mean +/- standard error of the mean) and had a greater degree of hypoxia (oxygen tension, 55 +/- 4 versus 80 +/- 6 mm Hg) (p less than 0.05 for all variables). Ten patients in group A and 8 patients in group B had right ventricular hypoplasia, based on an angiographically determined index. Balloon pulmonary valvotomy was attempted in 20 patients at the time of the initial catheterization but was unsuccessful in 9 owing to inability to catheterize the hypoplastic right ventricular outflow tract (n = 8) and to recurrent infundibular stenosis (n = 1). Patients with failed balloon valvotomy were subsequently operated on within 24 hours. The early operative mortality (less than 30 days) was 25% (7 of 28); one death (9%) occurred after successful balloon valvotomy owing to associated critical aortic stenosis. The early postoperative gradient was 20 +/- 2 mm Hg; the post-balloon valvotomy gradient was 18 +/- 3 mm Hg. We conclude that balloon pulmonary valvotomy yields good results in patients with critical pulmonary stenosis with essentially normal-sized right ventricle, whereas surgical pulmonary valvotomy is required for patients with right ventricular hypoplasia.

Blood Pressure↗
PubMed1990

Iliofemoral arterial complications of balloon angioplasty for systemic obstructions in infants and children.

The medical and radiological records of 64 consecutive infants and children who underwent transfemoral balloon dilation of the aorta or aortic valve were reviewed to determine the incidence, nature, and post-treatment outcome of acute iliofemoral complications. Balloon dilation angioplasty or balloon valvotomy was performed with 8F and 9F catheters without an arterial sheath. Patients ranged in age from 5 days to 15.4 years (mean, 6.4 years). Of 64 patients, 29 (45.3%) had an acute iliofemoral complication, including thrombosis (18 of 64), complete disruption (five of 64), incomplete disruption (three of 64), and arterial tear (three of 64). The arterial pathology was confirmed in 23 of 29 patients by one or a combination of surgical exploration and repair (18 of 29), angiography (six of 29), and magnetic resonance imaging (three of 29). Of eight patients, three with arterial disruption had acute hypotension requiring transfusion and immediate surgery; the other five had absent pedal pulses after the procedure. Of these five, three developed bleeding during thrombolytic therapy and underwent surgical exploration, and two were diagnosed by angiography after ineffective thrombolytic therapy. Angiography in three patients with iliac artery avulsion showed tapered occlusion in two and an aneurysm in one. In patients with iliofemoral thrombosis, angiography showed occlusion from the puncture site to the origin of the external iliac artery. Eleven patients (17% of the entire group and 38% of the group with acute iliofemoral complications) had reduced or absent pedal pulses at the time of discharge. A significant correlation was found between increased incidence of iliofemoral thrombosis and disruption (as well as abnormal pedal pulses at hospital discharge) and low patient weight.

Angioplasty, Balloon↗
PubMed1990

Coronary angiography of pulmonary atresia, hypoplastic right ventricle, and ventriculocoronary communications.

A retrospective study was undertaken to determine the spectrum of angiographic abnormalities of the coronary arteries in infants and children with pulmonary atresia, hypoplastic right ventricle, and right ventriculocoronary arterial communications. Twenty-nine patients with 67 angiographic examinations were reviewed; findings in seven patients were compared with those at autopsy. Twenty-seven (93%) of 29 patients had caliber abnormalities of the involved coronary arteries, including obstructive lesions in 20 (69%) of 29 and segmental dilatation in 16 (55%) of 29. Nine patients had interruption of the anterior descending artery and one had absent connection between the coronary arteries and the aorta. A single coronary artery was found in four of 29 patients. There was excellent correlation between clinical angiography and autopsy findings in seven patients. This study confirms the ability of high-quality clinical angiography to show significant abnormalities of the coronary arteries in infants and children with pulmonary atresia and ventriculocoronary communications.

Child↗
PubMed1990

Effects of low perfusate Ca2+ concentration on newborn myocardial function after ischemia.

A greater dependence on transsarcolemmal Ca2+ flux and immaturity of Ca2+ sequestration capacity may potentiate Ca2(+)-mediated reperfusion injury in the newborn myocardium. The effect of serum ionized Ca2+ concentration on left ventricular systolic and diastolic function after ischemia was studied in 5-7-day-old piglets undergoing a 90-minute period of cold-blood cardioplegic arrest. In the control group, Ca2+ was maintained at 1.2 mM (Group A [n = 6]). The cardioplegic solution and bypass perfusate were modified to achieve a low Ca2+ concentration, 0.25 mM, in Group B (n = 6). Left ventricular pressure-volume loops were acquired by using high-fidelity pressure-sensor-tipped and volume-conductance catheters. Ventricular function was assessed from the slope of end-systolic (Ees) and end-diastolic (k) pressure-volume relations during transient caval occlusion. Both groups showed a significant reduction in Ees after ischemia (p less than 0.05). Intergroup comparison of Ees after ischemia demonstrated a better recovery of the systolic function in the low Ca2+ group, 64 +/- 7% versus 49 +/- 6% in the normal Ca2+ group (p = 0.05). There was a significant increase in chamber stiffness index in group A (k, 0.48 +/- 0.06 to 0.65 +/- 0.05 ml-1, p less than 0.01) versus no significant change in group B. This study shows 1) the feasibility of acquiring continuous pressure-volume data in neonatal hearts by using a conductance catheter system, and 2) better preservation of systolic function and diastolic compliance in normal newborn myocardium by low Ca2+ concentration in the peri-ischemic period.

Animals↗
PubMed1989

[Serial determination of anthracycline poisoning in children].

Dose-related cardiotoxicity limits enthracycline administration in patients with solid tumours or leukaemia. Many patients (70%) would probably benefit by receiving more than a total accumulative dose of 500 mg/m2. As a measure of myocardial function the left ventricular ejection fractions (EF) were determined from serial radionuclide angiograms in 62 children who had at least 3 studies (mean age 8.4 +/- 5.4 years). Seven patients who had clinical evidence of cardiac involvement and/or a marked decline in their EF underwent endmyocardial biopsy (9 x). The EF declined progressively from 63 +/- 7% prior to chemotherapy to 60 +/- 5%, 58 +/- 7% and 54 +/- 7% after low, medium and high-dose anthracycline, respectively in the non-biopsied children vs 58 +/- 4%, 54 +/- 7% and 48 +/- 4% in the biopsied patients. Anthracycline dosage was 129 +/- 42, 307 +/- 68 and 471 +/- 61 mg/m2 and 103 +/- 64, 303 +/- 73 and 536 +/- 93 mg/m2, respectively. The biopsies were obtained at a mean anthracycline dose of 408 mg/m2 when the EF was 46 +/- 5%, and graded according to the modified Billingham score; grade 1 (6 x), 1.5 (2 x) and 2.5 (1 x). A decline in the EF was seen in 89% of our patients throughout their chemotherapy course, with a statistical significance of p less than 0.02 in the biopsied patients after medium dose therapy which was not seen in the non-biopsied children until they were receiving anthracyclines.

Biopsy↗
PubMed1989

A wire technique to cross the congenitally stenotic aortic valve.

We describe a double-catheter "rendezvous" technique that allows the successful placement of a balloon valvotomy catheter retrogradely across a congenitally stenotic aortic valve when traditional single-catheter retrograde methods fail. An important therapeutic procedure that might otherwise be abandoned can be completed with only the additional procedure of a transseptal atrial puncture and a second arterial entry.

Aortic Valve Stenosis↗
PubMed1989

Anaesthetic experience with paediatric interventional cardiology.

Anaesthetic and sedation techniques, complications and outcomes were reviewed in 176 children undergoing 184 interventional cardiologic procedures. Techniques included sedation only, and ketamine, inhalational or narcotic anaesthesia. Ketamine infusion was the technique most frequently used. Ketamine was associated with a higher incidence of respiratory complications (P less than 0.05) than the other techniques. The higher incidence of hypercarbia (15.6 per cent), which did not affect outcome, may be attributable to the use of supplemental sedatives. The incidence of upper airway obstruction (7.8 per cent) was similar to that of previous studies. Vascular compromise resulted from the procedure in 33 patients, necessitating surgical correction in 16. Cardiac perforation occurred in four cases, causing one death. Pulmonary valve stenosis was most amenable to balloon dilatation and aortic valve stenosis least amenable. ketamine was the anaesthetic agent preferred by cardiologists for use in the catheterisation suite when general anaesthesia was required. Vigilant monitoring by anaesthetic staff is necessary during the procedure, and avoidance of concomitant narcotics is recommended if a ketamine technique with spontaneous ventilation is used.

Adolescent↗
PubMed1989

Abnormal cardiac signs after Fontan type of operation: indicators of residua and sequelae.

Among 74 survivors of the Fontan type of operation abnormal cardiac signs were detected in 46 (62%) at postoperative examination. The findings were analysed in relation to the state of the cardiovascular system of these patients. Cyanosis was present in 10 (13.5%) patients. The causes of cyanosis included residual interatrial shunt (six patients), acquired pulmonary arteriovenous fistulas (three patients) and acquired systemic-to-pulmonary vein communication (one patient). Signs of chronic fluid retention were detected in six (8%) patients. In four of them the fluid retention was related to conduit obstruction and in the remaining two it was secondary to severe subaortic stenosis in one and atrioventricular valvar regurgitation in the other. Organic heart murmurs were heard in 29 (39%) patients. The aetiologies of these murmurs were multiple. They included aortic valve regurgitation (eight patients), subaortic stenosis (seven patients), atrioventricular valvar regurgitation (five patients), pulmonary valve regurgitation (five patients), residual Blalock-Taussig shunt (two patients), residual ventricular septal defect (two patients), residual communication in the main pulmonary artery which had been ligated but not divided (one patient), and left ventricular to right atrial shunting (one patient). Cardiac rhythm disturbances of varying aetiology were noted in 23 (31.1%) patients. Sixteen (21%) had supraventricular arrhythmias and seven (9.5%) had conduction abnormalities. The present review suggests that among survivors of the Fontan type of operation abnormal cardiac signs are indicators of residua or sequelae or both of the native cardiovascular anomalies or surgical procedures.

Adolescent↗
PubMed1989

Determination of left ventricular volumes by Simpson's rule in infants and children with congenital heart disease.

Regression equations were developed from left ventricular casts of known volumes to calculate left ventricular volumes from biplane cineangiography obtained in non-standard views. Volumes were calculated by Simpson's rule from casts of postmortem specimens from patients with congenital heart disease. The casts were divided into two groups: those that came from patients with abnormal right ventricular haemodynamic function (group 1, n = 11) and those that came from patients in which it was normal (group 2, n = 9). Biplane cinegrams were taken in conventional (anteroposterior/lateral, right anterior oblique/left anterior oblique) and non-conventional (long axis oblique, hepatoclavicular, and sitting up) projections. The true volume of each cast was determined from its weight and specific gravity. Correlations between measured and true volumes (r = 0.96 to 0.99) were excellent in all projections, although each projection overestimated the true volumes (slope = 0.72 to 0.94). The regression equations obtained from conventional views were significantly different from those from the non-conventional views; however, the regression slopes in group 1 were not different from those in group 2 in any view. Regression equations obtained by Simpson's rule do not seem to be affected by the haemodynamic state of the right ventricle. Different regression equations are required to measure left ventricular volumes from non-conventional angiograms.

Anthropometry↗
PubMed1989

Balloon dilatation of congenital aortic valve stenosis in infants and children: short term and intermediate results.

Percutaneous balloon dilatation of the aortic valve was attempted in 25 consecutive patients with stenosis. The aortic valve diameters were normal for age. The balloon catheters were placed retrogradely, and their diameters were within 1-2 mm of the valve diameter and 3 (13 patients) or 6 cm (recent 12 patients) long. After dilatation the pressure gradients across the aortic valve were reduced significantly and the valve areas, measured in 10 patients, increased. Aortic regurgitation was detected in six patients before (grade I) the procedure and in 15 patients (6 grade I, 6 grade II, 3 grade III) after the procedure. In one patient the aortic valve could not be crossed and in three there was no reduction in the pressure drop. Nine patients have a sustained reduction in Doppler assessed gradients. There were vascular complications in 12 and these required surgical intervention in three patients. Balloon dilatation seems to be an effective short term palliative procedure in patients with congenital stenosis of the aortic valve.

Adolescent↗
PubMed1989

Two-dimensional echocardiographic and color flow Doppler evaluation of ductal occlusion with the Rashkind prosthesis.

To evaluate the results of ductal occlusion with the Rashkind prosthesis, 78 children (group 1, 19 boys and 59 girls; mean age at occlusion, 4.5 +/- 4.0 years) with isolated patent ductus arteriosus (n = 73) or in association with other lesions (n = 5) were evaluated by pulsed and color flow Doppler 9 +/- 7 months (range, 2-26 months) after occlusion. Thirty children who had undergone patent ductus arteriosus ligation (group 2, 9 boys and 21 girls; mean age at study, 5.7 +/- 4.9 years; mean follow-up after ligation, 44 +/- 58 months) were evaluated in the same way. The prevalence of residual ductal shunting and the main pulmonary arterial flow patterns were recorded. Residual ductal shunting in group 1 was 38% on day 1, decreasing slowly to 31% at 3 months, 27% at 6 months, and 19.7% at 1 year or more due to further spontaneous shunt resolution. The residual shunting rate in group 2 (6%) was significantly lower than that at 1 year or more in group 1 (p less than 0.001). Successful reocclusion in 5 of 6 in a subset of patients in group 1 followed for 1 year or less reduced further the prevalence of residual shunting. Residual shunting after patent ductus arteriosus occlusion is more common than after ligation, but continues to decrease during follow-up.

Child, Preschool↗
PubMed1989

Reocclusion for persistent shunting after catheter placement of the Rashkind patent ductus arteriosus occluder.

Between February 1986 and January 1989, 105 percutaneous catheter occlusions of patent ductus arteriosus were undertaken, with six patients having residual left-to-right shunting confirmed by colour-flow Doppler nine months to years after initial occlusion. Five of six had successful reocclusion by placement of a second 12 mm Rashkind device. All successful reocclusions had continuous murmurs. Colour-flow Doppler characterized residual shunting as a discrete jet coursing superior to the device in five and through the pods in one. No left pulmonary artery obstruction was detected following placement of the second device. All patients were discharged the day of or the day following reocclusion.

Angioplasty, Balloon↗
PubMed1988

Catheter occlusion of the persistently patent ductus arteriosus.

Catheter occlusion of a persistently patent ductus arteriosus was attempted in 40 patients (11 men and 29 women, mean age 7.2 +/- 8.3 years, range 244 days to 40 years), using a transvenously placed Rashkind umbrella occluder (USCI). Thirty-one 12-mm and six 17-mm diameter devices were successfully placed in the ductus (internal diameter average 3.9 mm, range 2 to 9 mm). One procedure was abandoned when fluoroscopy failed to visualize the device. There were 2 immediate embolizations subjected to surgical recovery. A residual shunt was present on the immediate postocclusion ventriculogram in 12 of 37 procedures (32%). Twenty-eight patients (75%) have had at least a follow-up at 3 months with Doppler study and 6 (21%) continued to have shunting into the pulmonary artery. Three of 4 patients have undergone successful placement of a second device and 1 patient's shunting spontaneously resolved at 1 year postimplant, leaving only 2 patients (7%) with persistent shunts. There has been 1 episode of probable prosthetic endarteritis and 1 patient has developed mild narrowing of the left pulmonary artery related to device placement. Catheter occlusion of the patent ductus arteriosus using the Rashkind umbrella appears to be a safe and effective method of non-surgical management.

Adult↗
PubMed1988

Natural history and prognostic risk factors in endocardial fibroelastosis.

A retrospective study was made of 52 patients (16 men, 36 women) with endocardial fibroelastosis diagnosed by strict clinical criteria and confirmed histologically in 18 (35%). Clinical and hemodynamic manifestations at presentation were reviewed from the clinical record. The follow-up period averaged 47 months (range 1 day to 228 months). Actuarial survival rates were 93% at 6 months, 83% at 1 year and 77% at 4 years. Clinical and hemodynamic manifestation included onset at less than 1 year of age (89%), respiratory distress (71%), cardiomegaly on chest roentgenogram (99%), left ventricular hypertrophy with ST-T-wave changes on the electrocardiogram (97%) and reduced contractility with dilatation of the left ventricle (100%). Prognostic risk factors were evaluated comparing 13 patients who died (group 1) with 16 patients who survived greater than 4 years (group 2). Only cardiac index (2.8 +/- 0.8 vs 3.5 +/- 0.5 liter/min/m2) and ejection fraction (18 +/- 12 vs 33 +/- 21%) measured at catheterization were significantly reduced in group 1 compared with group 2 (p less than 0.005 and p less than 0.01, respectively). Careful observation and appropriate management are recommended in all patients, although low ejection fraction and cardiac output at presentation are predictive of poor outcome and support other therapeutic alternatives.

Child↗
PubMed1988

Correlation of left ventricular angiographic casts and biplane left ventricular volumetry in infants and children.

To calculate left ventricular (LV) volumes from biplane cineangiography obtained in nonstandard views, regression equations were developed from LV casts of known volume. Volumes were calculated by the area-length method from casts ranging from 1.4 to 48.9 ml obtained from 30 postmortem cases with heart disease. The casts were divided into 2 groups: group I (n = 17) with abnormal and group II (n = 13) with normal right ventricular hemodynamics. Biplane cinegrams were taken in the anterolateral, anterior and long axial oblique, hepatoclavicular and sitting-up projections. The true volume of each cast was determined from its weight and specific gravity. In both groups, excellent correlations were obtained between measured and true volumes (r = 0.92 to 0.99) in all projections, although each projection overestimated the true volume (slope value less than 1). The regression equations obtained from group I were significantly different from those in group II in all views (p less than 0.025 to 0.05), with smaller mean differences and standard errors of the estimate. These data support the concept that right ventricular hemodynamics influence ventricular septal position and, therefore, LV geometry and measured volumes. Appropriate regression equations are required to allow volume calculation from multiple projections.

Cardiac Volume↗