Biomedical subjects
Publications and source records attributed to R H Beekman.
Magnetic deflection forces and imaging artifact were assessed for 13 pediatric interventional cardiology devices. The magnetic deflection forces incurred by these devices are small compared with physiologic forces experienced in the cardiovascular system.
Hospital charges for coil occlusion were significantly less than for surgical closure of patent ductus arteriosus, and were reduced over time as experience permitted refinement of the coil occlusion protocol. The expected hospital charges for closure by a coil occlusion strategy, including the charges for surgical closure in patients with failed coil occlusion, was less than the hospital charges for surgical closure strategy under any reasonable estimate of coil occlusion efficacy.
Doppler estimation of RV dP/dt correlates well with micromanometer catheter-measured values in children with hypoplastic left heart syndrome. Doppler estimation of RV dP/dt is a method of quantifying RV systolic function independent of geometric assumptions, and may be a valuable method for longitudinal analysis of RV function.
In a canine puppy model, pulmonary artery stenosis was created by banding the left pulmonary artery to 30-40% of its original diameter. Animals underwent right heart catheterization and angiography 1-2 mo later, and Palmaz P308 stents were implanted. Stent redilation was performed 3-5 mo later. One mo postredilation, the animals were restudied and sacrificed. Coarctations of the aorta were created by transverse aortic incision and longitudinal repair. P308 stent implantation was performed 2-3 mo later. Stent redilation was performed after 6-10 mo, and the animals were restudied and sacrificed 1-2 mo later. Stent implantation was performed in 6 puppies with pulmonary artery stenosis, as 2 animals developed postoperative pulmonary arterial hypoplasia, precluding stenting. The stenosis diameter increased from 4.8 +/- 0.5 mm to 7.4 +/- 0.6 mm (mean +/- SE) following stenting (P = 0.005), and increased further to 9.2 +/- 0.7 mm following redilation (P < 0.001). There were no significant vessel tears or ruptures. Coarctation stenting was performed in 8 animals. The coarctation was dilated from 5.8 +/- 0.9 mm to 9.8 +/- 0.6 mm (P < 0.001), and to 13.5 +/- 0.5 mm at redilation (P = 0.002). Redilation could not be performed in 1 animal. Aortic rupture and death occurred in 2 of 7 animals at redilation. Stent implantation and redilation in experimental pulmonary artery stenosis appears safe and effective. Though stent implantation for coarctation of the aorta appears safe, there was a 28% aortic rupture rate at stent redilation in this model.
A novel, transhepatic approach to mitral valvuloplasty is described in a patient with an inferior vena caval filter. After transhepatic transseptal puncture, an Inoue dilatation catheter was passed through the hepatic parenchyma and across the atrial septum. Balloon mitral valvuloplasty was performed without complications. This approach should be considered when femoral venous access is restricted or is not feasible.
We describe the development of hemolysis from moderate residual shunting across a patent ductus arteriosus following coil embolization. The fall in hemoglobin levels from 11.6 to 6.0 gm/dl necessitated a second coil procedure which resulted in complete closure of the residual shunting and resolution of hemolysis. Therefore, appearance of anemia following coil embolization of patent ductus arteriosus should be monitored closely; however, repeat coil embolization with elimination of residual shunt will lead to prompt recovery of normal hemoglobin levels.
OBJECTIVE: We sought to determine the prevalence and fate of residual ductal shunting following coil occlusion of patent ductus arteriosus. BACKGROUND: Although transcatheter coil occlusion of patent ductus arteriosus has gained popularity, few follow-up data have been reported. METHODS: A review of 75 patients who underwent coil occlusion was performed. Residual shunting was investigated by Doppler echocardiography in follow-up. Angiograms were reviewed to obtain minimal ductal diameter and ductal angiographic type. RESULTS: Residual shunts were found in 31 patients (41%) on the day of the procedure, and of these, spontaneous closure was noted in 17 (55%) at 2 weeks to 20 months of follow-up. Of the 75 patients studied, 5 (7%) required a second coil procedure, and 10 (13%) remained with persistent residual shunts at most recent follow-up. Actuarial analysis estimated a 6 +/- 5% prevalence of residual shunts 20 months after a single coil procedure and 3 +/- 3% after all coil procedures. Minimal ductal diameter was associated with immediate complete ductal occlusion by a single coil. These patients had significantly smaller (p = 0.003) minimal ductal diameters (1.2 +/- 0.7 mm) than those who required two coils during their initial procedure to achieve immediate occlusion (1.9 +/- 0.7 mm), those who required a second coil procedure (2.0 +/- 0.9 mm), those who had spontaneous closure of residual shunts (1.9 +/- 0.7 mm) and those with persistent residual shunts (2.0 +/- 0.9 mm). No association was identified between ductal angiographic type and outcome of coil occlusion. No late adverse clinical events of coil occlusion or evidence of recanalization was found. CONCLUSIONS: Small residual shunts are common after coil embolization of patent ductus arteriosus, but most close spontaneously. Actuarial analysis estimates complete closure in 94% at 20 months, and reintervention was required in only 7% of patients.
Experience with transcatheter closure (TCC) of patent ductus arteriosus (PDA) in small infants is limited. Our goals were to evaluate the immediate and short-term results of TCC of PDA in small infants (< or = 8 kg) as attempted with single or multiple Gianturco coils and to compare results for PDA < or = 2.5 mm versus PDA > 2.5 mm. Twenty-four infants underwent an attempt at TCC of PDA at a median age of 0.7 years (range 2 weeks to 1.5 years) and median weight of 6.5 kg (range 2.3 to 8 kg). Coils were placed by the transvenous route in 14 patients and by the transarterial route in 10 patients. The median PDA diameter was 2.7 mm (range 0.4 to 5.2 mm). Ten patients had PDA diameters < 2.5 mm and all had complete closure, 9 with a single coil and 1 with two coils. Fourteen patients had PDA diameters > or = 2.5 mm; closure was complete in 10 patients, 9 of whom required multiple coils. There was a trend toward improved results with multiple coils delivered transvenously. There was immediate complete closure of the PDA with a diameter as large as 5.2 mm that persisted at a median follow-up period of 1.2 year. Closure was unsuccessful in 4 patients, each of whom required multiple coils. The median fluoroscopy time was 19 minutes. Complications included transient loss of femoral pulse in 2 infants, mild left pulmonary artery obstruction in 2, and nonretrievable coil migration to the right lung in one. We conclude that TCC is effective therapy for small infants with a PDA of diameter < or = 5.2 mm by the single-or multiple-coil technique on an outpatient basis and that TCC can be performed in neonates as small as 2.3 kg.
OBJECTIVE: MR imaging and cineangiography were compared in the evaluation of central pulmonary arteries in patients with obstructive lesions of the right ventricular outflow tract. SUBJECTS AND METHODS: Prospectively, we obtained multiplanar spin-echo cardiac-gated MR images and cineangiograms in 29 patients who had obstructive lesions of the right ventricular outflow tract (31 examinations). Blinded first observers evaluated the presence, size, confluence, and stenoses of the pulmonary artery and the presence of aortopulmonic collaterals. Blinded second observers evaluated the presence and size of the pulmonary artery. RESULTS: Each imaging technique revealed pulmonary arteries that were not shown by the other technique. We measured pulmonary arteries as being smaller on MR images; however, we found good correlation between the two techniques (r value for right pulmonary arteries = .82, r value for left pulmonary arteries = .88). MR imaging revealed five of six stenoses in the left pulmonary artery, but our observers falsely identified five right pulmonary arteries as stenotic from MR images. Interobserver variability and intraobserver variability in estimating size of the pulmonary artery on MR images and cineangiograms were similar and were less than variability when paired estimations in the same patient with both imaging techniques were compared. CONCLUSIONS: MR imaging and cineangiography should be viewed as complementary techniques.
BACKGROUND: In some children with congenital heart disease, conventional venous access is unavailable for cardiac catheterization. This study investigates a novel transhepatic venous approach to cardiac catheterization in children and evaluates its efficacy and safety. METHODS AND RESULTS: Percutaneous transhepatic puncture was performed using a 22-gauge Chiba needle under fluoroscopic guidance. After wire exchanges were performed, a 5F to 8F sheath was positioned in the low right atrium and cardiac catheterization was performed. On completion of the catheterization, the sheath was withdrawn and a 3-mm steel coil was placed in the parenchymal tract between the hepatic vein and liver capsule. Liver enzyme studies were obtained before and after transhepatic catheterization, and an abdominal ultrasound was performed to evaluate the liver 24 hours after the procedure. Percutaneous transhepatic cardiac catheterization was performed successfully in 17 of 18 children in whom it was attempted. Patient age was 30 +/- 8 months (mean +/- SEM; range, 1 day to 9 years), weight was 10.5 +/- 1.5 kg (3.1 to 27.5 kg), and mean right atrial pressure was 10 +/- 1 mm Hg (5 to 19 mm Hg). Time from initial needle puncture to right atrial entry was 6.2 +/- 1.2 minutes. Diagnostic catheterization was performed successfully in all 17 children, and additional interventional procedures were performed in 5 children. The total catheterization time was 2.0 +/- 0.2 hours. Serum aspartate aminotransferase increased from 57 +/- 15 to 78 +/- 8 IU/L (P = .06), but alanine aminotransferase and gamma-glutamyl transpeptidase did not change. Ultrasound was performed 24 hours after transhepatic catheterization, and no evidence was found in any patient of hemorrhage or subcapsular hematoma. CONCLUSIONS: These data suggest that this novel transhepatic approach provides an effective and safe route for diagnostic and interventional cardiac catheterization in children.
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The effectiveness of a single-stage anterior approach for the repair of aortic arch obstruction and associated intracardiac defects has not been well evaluated. We therefore reviewed our experience with 60 neonates (median age 8 days, range 1 to 28) who underwent a single-stage repair by way of a median sternotomy at our institution between 1986 and 1994. Nineteen (32%) had coarctation with ventricular septal defect, 18 (30%) had interrupted aortic arch with ventricular septal defect, and 23 (38%) had coarctation or interrupted aortic arch with complex intracardiac anatomy. The arch obstruction was repaired using resection and primary anastomosis in 54 patients, synthetic patch aortoplasty in 3, subclavian flap aortoplasty in 2, and an interposition gortex graft placement in 1. Total circulatory arrest time was 48 +/- 3 minutes (mean +/- SEM). There were 7 early postoperative deaths (11.7%; 70% confidence limit 8% to 16.6%). The 53 survivors were followed for a mean of 23 months (range 1 to 78), for a total of 1,219 patient-months. Recurrent arch obstruction > or = 20 mm Hg has occurred in 2 of 53 patients (3.8%; 70% confidence limit 1.9% to 7.5%); both underwent successful balloon angioplasty. There were 2 late deaths, 1 of which was noncardiac. We conclude that repair of aortic arch obstruction and intracardiac defects by a single-stage approach through median sternotomy can be accomplished with low mortality in infancy, even with associated complex intra-cardiac anatomy. Recurrent coarctation is relatively uncommon and can be successfully managed with balloon angioplasty.
The objective of this study was to assess the effectiveness of balloon valvuloplasty in the young adult with congenital aortic stenosis and to compare its effectiveness with children. Percutaneous balloon valvuloplasty is effective in children with congenital aortic stenosis, but not in adults with acquired calcific aortic stenosis. Because effectiveness of balloon valvuloplasty in young adults with congenital aortic stenosis is not well defined, we evaluated the outcome in 15 patients aged 16-24 years (18 +/- 0.6; mean +/- SEM) who underwent balloon valvuloplasty from 1985 to 1993. The aortic valve annulus diameter ranged from 18.5 to 30 mm (24 +/- 0.9). The aortic valve was bicuspid in 12 and tricuspid in 3 patients, and calcification was present in one patient. Balloon valvuloplasty was performed using a double balloon technique in 12 patients and a single balloon technique in three patients. Three patients had inadequate relief of gradient with a residual peak systolic gradient > or = 70 mm Hg. Three patients required valve replacement-two patients for a residual gradient > or = 70 mg Hg, and one patient 4 years later for severe aortic valve regurgitation. Eight of the remaining 12 have undergone elective follow-up catheterization 1.2-2.5 years (1.5 +/- 0.1) later. The peak systolic aortic valve gradient decreased by 55% from 73 +/- 5.8 mm Hg to 35 +/- 5.4 mm Hg immediately postvalvuloplasty, and was 30 +/- 4.4 mm Hg at follow-up (P < 0.001). The left ventricular systolic pressure decreased from 179 +/- 7.5 to 147 +/- 6.5 mm Hg immediately postvalvuloplasty and was 147 +/- 4 mm Hg at follow-up. Aortic insufficiency was unchanged after valvuloplasty in 9, increased by 1+ in 4, and by 2+ in 2 patients. Balloon valvuloplasty was as effective in these young adults as in 70 children (age 6 +/- 0.7 years) with congenital aortic stenosis (peak systolic gradient pre- 79 +/- 3 mm Hg versus post- 34 +/- 2 mg Hg; at 1-2 years follow-up 34 +/- 4 mm Hg). Balloon valvuloplasty provides effective treatment in most young adults with congenital aortic stenosis, without early restenosis. Balloon valvuloplasty is as effective in young adults as in children, where it is currently the treatment of choice.
OBJECTIVES: This study reviewed our experience with percutaneous balloon valvotomy in infants with critical pulmonary stenosis or membranous pulmonary atresia with intact ventricular septum and defined the anatomic and hemodynamic characteristics of infants in whom this procedure is successful and provides definitive therapy. BACKGROUND: Unlike children with valvular pulmonary stenosis, the follow-up of infants with critical pulmonary stenosis undergoing percutaneous balloon valvotomy is limited. METHODS: Between December 1987 and August 1992, percutaneous balloon valvotomy was attempted in 12 infants with critical pulmonary stenosis (n = 10) or pulmonary atresia with intact ventricular septum (n = 2). Two outcome groups were identified: Group A patients are acyanotic, have mild residual pulmonary stenosis and have not required operation; Group B patients have required operation. RESULTS: Of the 12 infants, 11 had a successful balloon valvotomy procedure. Group A patients (n = 7) have a residual gradient of 22 +/- 18.7 mm Hg (mean +/- SD) at follow-up of 3.2 years (range 1.2 to 5.0). In Group B (n = 5), operation was required for inability to cross the pulmonary valve (n = 1) or persistent severe hypoxemia for > or = 2 weeks after valvotomy (n = 4). Significant differences (p < or = 0.01) between the two groups (Group A vs. Group B) were identified in pulmonary valve annulus (Z value) 8.1 mm (-1.1) versus 5.5 mm (-3.4); tricuspid valve annulus (Z value) 14.0 mm (0.8) versus 8.8 mm (-1.8); right ventricular volume 65 versus 29 ml/m2; and Lewis index 10.9 versus 8.9. CONCLUSIONS: Percutaneous balloon valvotomy is effective and likely to provide definitive therapy in infants with critical pulmonary stenosis or membranous pulmonary atresia with intact ventricular septum who have a tricuspid valve annulus > 11 mm, pulmonary valve annulus > or = 7 mm and right ventricular volume > 30 ml/m2.
Since September 1991, 14 consecutive patients with tetralogy of Fallot, pulmonary atresia, and diminutive pulmonary arteries have undergone staged repair. All patients had multiple aortopulmonary collateral arteries and the ductus arteriosus was absent in 11. Mean sizes of the right and left pulmonary arteries were 2.2 +/- 0.7 mm and 1.9 +/- 0.8 mm, respectively (range 0.5 to 3.0 mm). Eight patients (57%) have subsequently received complete repair. Age at initial procedure (shunt, right ventricle-pulmonary artery conduit, or direct aorta-pulmonary artery anastomosis) in this group was 5.3 +/- 6.8 months. The number of operative procedures to achieve complete repair was 2.9 +/- 0.8 per patient (range 2 to 4). Intraoperative postrepair peak right ventricle-left ventricle pressure ratio was 0.57 +/- 0.17. Six of 8 patients (75%) required additional interventional procedures (mean 1.5 +/- 1.2 per patient) for angioplasty of peripheral pulmonary artery stenoses, coil embolization of aortopulmonary collateral arteries, or intra-operative insertion of intravascular pulmonary artery stents. Mean follow-up from complete repair was 8.7 +/- 8.3 months (range 0.5 to 23.8 months) and is complete. There was one in-hospital death at 45 days, and one late cardiac death at 20.3 months. Six patients had initial palliative operations (unifocalization, right ventricle-pulmonary artery conduit, direct aorta-pulmonary artery anastomosis, or transannular outflow patch) but have not undergone complete repair. Age at initial procedure in this group was 27.9 +/- 56.9 months (range 0.27 to 155 months), and mean follow-up from initial procedure was 10.9 +/- 11.2 months (range 0 to 31.4 months). The operative mortality rate was 33% (2 of 6 patients). There was one late noncardiac death at 5.3 months. Three patients are awaiting further intervention or repair. This experience suggests that complete repair is feasible even in patients with extremely diminutive pulmonary arteries (< or = 3.0 mm). Pulmonary artery growth is facilitated by early (3 to 6 month) establishment of central pulmonary artery flow by right ventricle-pulmonary artery conduit (pulmonary arteries > 1.5 mm) or by direct ascending aorta-pulmonary artery anastomosis (pulmonary arteries < 1.5 mm). Subsequent interventional catheterization and operative procedures as required for pulmonary artery stenoses and coil embolization of collateral arteries allow continued recruitment of central pulmonary arteries and may obviate or minimize the need for unifocalization procedures.
The optimal treatment of critical aortic stenosis in the neonate and infant remains controversial. We compared transventricular dilation using normothermic cardiopulmonary bypass and percutaneous balloon aortic valvuloplasty with respect to early and late survival, relief of aortic stenosis, degree of aortic insufficiency, left ventricular function, and freedom from reintervention. Between July 1987 and July 1993, 30 neonates and infants underwent transventricular dilation or balloon aortic valvuloplasty for critical aortic stenosis. The patients in the transventricular dilation group (n = 21) ranged in age from 1 to 59 days (mean age 18.0 days +/- 19.1 days) and the balloon aortic valvuloplasty group (n = 9) from 1 to 31 days (mean age 10.0 days +/- 9.0 days). There were no significant differences in weight, body surface area, or aortic anulus diameter between the two groups (p = 1.0). Associated cardiovascular anomalies were more common in the transventricular dilation group (48%) than in the balloon aortic valvuloplasty group (11%). After intervention, the degree of residual aortic stenosis and insufficiency was equivalent in the two groups as assessed by postprocedural Doppler echocardiography. Ejection fraction improved within both groups (transventricular dilation 39% +/- 20.2% versus 47% +/- 22.0%; balloon aortic valvuloplasty 51% +/- 16.1% versus 62% +/- 8.4%), and there was no significant difference between groups. The left ventricular mass/volume ratio increased within both groups (p < 0.05) but with no significant difference between groups (transventricular dilation 1.4 +/- 0.5 gm/ml versus 1.8 +/- 0.6 gm/ml; balloon aortic valvuloplasty 1.1 +/- 0.6 gm/ml versus 1.7 +/- 0.4 gm/ml). Early mortality in the transventricular dilation group was 9.5% and in the balloon aortic valvuloplasty group, 11.1%. There was one late death in the transventricular dilation group. Four patients from the transventricular dilation group (19%) and two patients from the balloon aortic valvuloplasty group (22%) required reintervention for further relief of aortic stenosis. We conclude that both transventricular dilation and balloon aortic valvuloplasty provide adequate and equivalent relief of critical aortic stenosis. The treatment strategy adopted should depend on other factors, including associated cardiovascular anomalies, vascular access, preoperative condition, and the technical expertise available at each institution.
Balloon valvuloplasty for pulmonary valve stenosis by static dilation is the treatment of choice for the treatment of isolated valvular pulmonary stenosis in the infant, child, and adolescent. The procedure is also effective in neonates; however, the complications of the procedure are significantly higher and the efficacy is less. This article reviews the background, indications, technique, acute and long-term results, and complications of balloon valvuloplasty for pulmonary valve stenosis in the infant, child, and adolescent with pulmonary valve stenosis. The application of this technique in neonates with critical pulmonary stenosis or membranous pulmonary atresia with intact ventricular septum is also discussed. The determinants of a successful outcome in each group are addressed.
The first transcatheter closure of an atrial septal defect (ASD) was performed by King and Mills in 1976. The Lock Clamshell occluder and the buttoned device are the latest devices to undergo clinical trials. Successful transcatheter closure has been possible with minimal morbidity and mortality. Small residual shunts may remain, however, in up to 20% of patients 1 year after the procedure. The clinical significance and natural history of these small residual atrial communications remains to be determined. This article reviews the history and development of the current ASD closure techniques, with emphasis on the experience with the Lock Clamshell occluder and the buttoned device.