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Biomedical subjects

R H Beekman

Publications and source records attributed to R H Beekman.

At least 55 records · Page 3Linked to original sources
PubMed1995

Embolization therapy in pediatric cardiology.

Transcatheter embolization therapy has assumed an important role in the management of patients with congenital heart disease. A variety of embolization materials, most commonly steel coils, is available to treat or palliate patients with aortopulmonary collateral vessels or surgical shunts, arteriovenous malformations, and anomalous venovenous connections (common after surgical intervention for the univentricular heart). At many centers, coil occlusion has recently become the treatment of choice for patients with a restrictive patent ductus arteriosus (PDA). This article describes the materials and techniques of embolization therapy, as well as the common indications encountered in the practice of pediatric interventional cardiology.

Angiography↗
PubMed1994

Late follow-up of balloon angioplasty in children with a native coarctation of the aorta.

Between May 1984 and April 1993, 59 children underwent balloon angioplasty of a native coarctation at our institution. The follow-up protocol included a cardiac catheterization 1 to 2 years after angioplasty, which was performed in 90% of patients with > or = 2 years follow-up. Angioplasty caused an acute decrease in peak systolic gradient from 46 +/- 2 to 15 +/- 2 mm Hg, without early aneurysm or emergent surgical intervention in any patient. Based on follow-up data, a satisfactory result was obtained in 38 patients (64%; 70% confidence limit: 58% to 71%), defined as a residual systolic gradient < 20 mm Hg and no aneurysm. In these patients the gradient decreased acutely from 43 +/- 2 to 9 +/- 1 mm Hg, was 6 +/- 1 mm Hg at follow-up catheterization, and 9 +/- 2 mm Hg by clinical evaluation 4.4 +/- 0.3 years after angioplasty. Twenty-one patients (36%; 70% confidence limit: 29% to 42%) had an unsatisfactory result due to a residual gradient > or = 20 mm Hg (n = 19) or aneurysm formation (n = 3), or both. Restenosis occurred in 6 patients, and occurred more in infants than in children > or = 12 months of age (3 of 5 infants vs 3 of 41 children, p = 0.01). Thus, balloon angioplasty provides an effective initial treatment strategy for native coarctation in most children aged > 12 months.

Adolescent↗
PubMed1994

Atrial septal defect occlusion with the buttoned device (a multi-institutional U.S. trial).

A clinical trial was conducted of the buttoned device for transcatheter closure of ostium secundum atrial septal defect. Occlusion was attempted in 57 patients aged 1 to 62 years (median 5). The procedure was abandoned in 7 patients after 1 or more unsuccessful attempts, and devices were released in 50 patients. Urgent surgical retrieval was necessary in 4 patients because of unstable device position: 3 devices "unbuttoned," with migration of the counteroccluder to the pulmonary artery or inferior vena cava, and 1 intact device embolized to the main pulmonary artery. All patients remained stable and underwent successful operation. Successful device implantation was therefore achieved in 46 patients, with immediate reduction in Qp/Qs from 1.8 +/- 0.6 to 1.1 +/- 0.2 (mean +/- SD, p < 0.0001). At most recent follow-up (1 to 20 months), 45 of 46 patients (98%) have no shunt or a trivial residual shunt. The prevalence of residual shunts declined from 65% at 1 month to 19% at 12 months after the occlusion procedure (p < 0.0001). Complications included unbuttoning of a fourth device, transient tricuspid regurgitation in 2 patients, and transient mitral regurgitation in 2 patients. An episode of asymptomatic atrial flutter was noted in a 46-year-old patient which may have been related to device implantation, but which has not recurred. There have been no cases of endocarditis or thromboembolism in 350 patient-months of follow-up. The buttoned device provided effective closure of the atrial septal defect in 45 of 57 patients (79%) in whom implantation was attempted and in 45 of 46 patients (98%) in whom device implantation was successfully accomplished.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Comparison of a low osmolarity nonionic radiographic contrast agent with a standard medium on renal function in cyanotic and normal dogs.

Renal dysfunction may follow administration of iodinated radiographic contrast agents. This complication may be less common when low osmolarity nonionic agents are used. Although potential benefits from the use of low osmolarity nonionic contrast may be minimal in individuals with normal physiology, a greater benefit has been postulated in the presence of chronic cyanosis. To test this hypothesis, six adult mongrel dogs underwent anastomosis of the inferior vena cava to the left atrium. This produced chronic cyanosis with a mean pO2 of 48 +/- 4 mm Hg and polycythemia with a mean hematocrit of 56 +/- 2 gm%. Three to 5 months after preparation, these cyanotic dogs and five control dogs each received diatrizoate (a high osmolarity ionic agent) or ioversol (a low osmolarity nonionic agent), 465 mg iodine/kg body weight, by intravenous bolus injection. One month later, each animal received the other agent. The order of administration was randomized. Renal function studies, including serum creatinine and creatinine clearance, were performed precontrast, after 60 min, and 24 hr postcontrast. Neither agent adversely affected renal function in either the cyanotic or the normal group. We conclude that at the doses that are commonly used in clinical practice, high osmolarity ionic contrast agents do not create a greater risk of renal injury than do low osmolarity nonionic agents in this model of cyanosis.

Angiocardiography↗
PubMed1994

International experience with secundum atrial septal defect occlusion by the buttoned device.

Several devices are available for transcatheter occlusion of atrial septal defect. This report describes the international experience with the buttoned device. During a 4.5-year period ending in February 1993, 180 transcatheter atrial septal defect occlusions were performed with the buttoned device. Patient age varied between 0.6 and 76 years and stretched atrial defect diameter between 5 and 25 mm. The defects were closed with 25 to 50 mm devices delivered through 8F (148 patients) or 9F (32 patients) sheaths. Twelve patients were adults whose defects were closed to prevent recurrence of cerebrovascular accidents caused by presumed paradoxic embolism. In the remaining patients the atrial defect was closed to treat the left-to-right shunt. The atrial septal defects were effectively occluded as demonstrated by (1) decrease in pulmonary-to-systemic flow ratio from 2.1 +/- 0.6 (mean +/- SD) to 1.05 +/- 0.1 (p < 0.01) by oximetry; (2) normalized S2 and disappearance of the diastolic murmur by auscultation; and (3) improvement in right ventricular volume overloading by echocardiogram. However, trivial to small shunts could be detected by color Doppler studies in 76 (45%) of 168 patients in whom such data are available. Complications included unbuttoning in 13 and whole-device embolization in 1. All patients remained stable, and retrieval of the device and surgical closure of the atrial septal defect were accomplished in 10 patients. Transcatheter retrieval was used in the remaining 4 patients. The incidence of unbuttoning, a major complication of the procedure, appeared to decrease with the increasing experience of the investigators and with device modification (third-generation). The follow-up duration varied between 1 month and 4 years. Six patients required surgery during the follow-up period. In the remaining patients (n = 160), clinical examination did not reveal signs of atrial shunts. Color Doppler studies revealed either complete disappearance of the previously demonstrated shunts or further diminution of their size. The results indicate that transcatheter occlusion of the atrial septal defects with buttoned devices is feasible, relatively safe, and effective, and it appears to be a viable alternative to surgery for some patients with secundum atrial septal defect. Complications are infrequent and should improve with experience.

Cardiac Catheterization↗
PubMed1994

Systemic ventricular outflow obstruction progresses after the Fontan operation.

To evaluate the course of systemic ventricular outflow obstruction after the Fontan operation, the records of 57 hospital survivors of that procedure were reviewed. Ventricular outflow obstruction was identified in 7 patients (group 1) and was absent in 50 patients (group 2). Overall, the ventricular outflow gradient in group 1 was 6.3 +/- 2.9 mm Hg (mean +/- standard error) before the Fontan operation and 7.6 +/- 3.9 mm Hg at hospital discharge. Ventricular outflow obstruction subsequently progressed to 80.1 +/- 17.3 mm Hg (range, 33 to 165 mm Hg; p < 0.02) a mean of 28 months postoperatively. One patient died of severe progressive ventricular outflow obstruction. Group 1 did not differ from group 2 in age, ventricular morphology, presence of a subaortic outflow chamber, prior shunt, or length of follow-up. Compared with group 2, however, patients in group 1 more commonly had an aorta arising from a hypoplastic ventricle (p < 0.001) and had undergone prior pulmonary artery banding (p = 0.005). We conclude that systemic ventricular outflow obstruction occurs commonly after a Fontan procedure (incidence, 12%; 70% confidence interval, 9% to 18%) and is a progressive lesion.

Child, Preschool↗
PubMed1994

Central pulmonary artery growth patterns after the bidirectional Glenn procedure.

The changes in pulmonary artery size and hemodynamics in 30 patients with univentricular cardiac anatomy were examined before and after bidirectional Glenn procedures done between October 1989 and February 1992. Serial angiographic and hemodynamic examinations before and 17.6 +/- 1.6 months after bidirectional Glenn procedures were compared. At the follow-up study there was no significant change in diameter of the pulmonary artery ipsilateral to the bidirectional Glenn shunt, however, a significant decrease was noted in the diameter of the pulmonary artery contralateral to the bidirectional Glenn shunt (p = 0.04). There was also a 32% decrease in the Nakata index of total cross-sectional pulmonary artery area after the bidirectional Glenn procedure (p = 0.004). Total pulmonary blood flow and mean pulmonary artery pressure had decreased, and arterial oxygen saturation had increased at follow-up. These changes, however, did not correlate with the observed changes in pulmonary artery size. By linear regression analysis, a significant relationship was identified between the Nakata index before the bidirectional Glenn procedure and the absolute change in Nakata index (r = 0.83). A significant decrease in Nakata index occurred only in patients with a bidirectional Glenn shunt in place more than 15 months. Sixteen of the 30 patients subsequently underwent total cavo-pulmonary anastomosis with 7 requiring concurrent surgical pulmonary artery reconstruction. Changes in pulmonary artery size observed more than 15 months after the bidirectional Glenn procedure may have implications for subsequent Fontan repair in children with univentricular anatomy.

Arteriovenous Shunt, Surgical↗
PubMed1993

Usefulness of the bidirectional Glenn procedure as staged reconstruction for the functional single ventricle.

The bidirectional Glenn operation may be particularly useful as an intermediate procedure before Fontan correction in high-risk patients. From October 1989 through February 1992, 50 patients 1 to 60 months old (median 12) have undergone a bidirectional Glenn operation. Diagnoses included hypoplastic left heart syndrome in 21 patients, pulmonary atresia with intact ventricular septum in 10, tricuspid valve atresia in 9, other complex univentricular heart defects in 9, and Ebstein's anomaly in 1. Mean pulmonary vascular resistance was 2.2 +/- 0.2 Wood U (range 0.5 to 7.3) and mean pulmonary artery area Nakata index was 318 +/- mm2/m2 (range 80 to 821). Additional procedures were performed in 17 patients, including pulmonary artery reconstruction in 15 (29%) and bilateral caval anastomoses in 5 (10%). There were 4 hospital deaths (8%). Two deaths resulted from myocardial infarction in patients with pulmonary atresia with intact ventricular septum and sinusoids and 1 from severe pulmonary vascular disease in a patient with hypoplastic left heart syndrome. There was 1 late death from pneumonia. Actuarial survival is 92 +/- 4% at 1 month and beyond, with a mean follow-up of 13.4 +/- 1 months. Risk factor analysis showed that pulmonary vascular resistance > 3 Wood U and pulmonary artery distortion were associated with increased mortality. Twelve patients have undergone a Fontan procedure at a mean duration after bidirectional Glenn of 18 months with 1 death (8%). The bidirectional Glenn procedure provides excellent palliation in high-risk patients and appears useful as a staging procedure before Fontan correction.

Anastomosis, Surgical↗
PubMed1993

Doppler evaluation of femoral arteries in children after aortic balloon valvuloplasty or coarctation balloon angioplasty.

To assess long-term femoral artery complications after aortic balloon valvuloplasty or coarctation balloon angioplasty, we examined 19 children who were 3 weeks to 21 years old (mean 7.6 years) at the time of catheterization. Two-dimensional and Doppler echocardiographic examinations of the common, superficial, and deep femoral arteries were performed at an average of 2.0 years after balloon dilatation. Pulsatility index (PI) was calculated as the maximum velocity minus the minimum velocity divided by the mean velocity. No patient was suspected clinically of having peripheral arterial disease prior to the echocardiographic examination. Fourteen patients had normal femoral arteries. Of these, 10 had normal two-dimensional and Doppler echocardiographic examinations of both femoral arteries. These patients had triphasic flow patterns (forward in systole, reverse in early diastole, forward in middiastole) and Pls of 3.7-41.6 (mean 9.5). Four of the 14 normal patients had abnormal pulsed Doppler examinations showing continuous forward flow and low Pls (1.7-3.5) reflecting residual coarctation (10-30 mmHg gradients). Five patients had abnormal femoral arteries. Of these, two had no visible obstruction by two-dimensional echocardiography and color-flow imaging but had abnormal pulsed Doppler patterns (continuous forward flow and low Pls of 2.5 and 2.9) only on the side of the balloon catheter insertion. Three of the five abnormal patients had visible obstructions by two-dimensional echocardiography and color-flow imaging and had abnormal pulsed Doppler patterns (continuous forward flow and low Pls from 1.1-3.6).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1993

Severe mitral insufficiency in mucopolysaccharidosis type III-B (Sanfilippo syndrome).

A 6-year-old girl with mucopolysaccharidosis (MPS) III-B (Sanfilippo syndrome) who developed severe mitral regurgitation and congestive heart failure requiring surgery (valvuloplasty) is reported. One year after surgery the patient remains well, with marked improvement in her physical activity, and without signs of heart failure. This is only the second report of severe mitral regurgitation in MPS III, and is the first report of a successful repair (valvuloplasty) of a dysplastic mitral valve in the MPS. Mitral valvuloplasty should be considered instead of valve replacement in any MPS patient with mitral valve regurgitation requiring surgery.

Adult↗
PubMed1993

Radiography of thoracic intravascular stents in children with congenital heart disease.

Seventeen balloon expandable stents were placed in thoracic vessels in eleven children with vascular stenoses related to congenital heart lesions. We describe the normal radiographic appearance of three types of balloon expandable stents implanted in pulmonary arteries, pulmonary veins, and the superior vena cava of these children as well as the appearance of the complications we encountered. Knowledge of the radiographic appearance of these devices is important as chest radiography is a primary method of follow-up in children with balloon expandable stents placed to treat stenoses of intrathoracic vessels related to congenital heart disease.

Adolescent↗
PubMed1993

Balloon-expandable stent treatment of experimental coarctation of the aorta: early hemodynamic and pathological evaluation.

The present study was intended to evaluate the acute and short-term hemodynamic, angiographic, and pathological response to balloon-expandable stent treatment of experimental coarctation of the aorta. A discrete thoracic coarctation was surgically created in six mongrel dogs (two adults, four puppies). Two months postoperatively all six dogs (8.9-30 kg) underwent left heart catheterization and coarctation stenting performed through a femoral artery cutdown. A Palmaz PS-30 stent was advanced to the coarctation through a 10 French sheath, and expanded with an angioplasty balloon chosen to equal the diameter of the proximal aorta (9-12 mm). Stent implantation was successful in each dog. The systolic pressure gradient decreased from 26.3 +/- 9.1 mmHg (mean +/- SE) to 0.5 +/- 0.5 mmHg (P = 0.04), and the coarctation diameter improved from 50 +/- 6% to 82 +/- 6% of the diameter of the proximal descending aorta (P less than 0.01). Follow-up catheterization 4-7 weeks after stenting documented no stent migration, early restenosis, thrombosis, obstruction of arterial side branches, or aneurysm formation. Pathological evaluation of the explanted segments of stented aorta documented that by 6-7 weeks the stents are covered by a neointima composed of intimal proliferation and fibrosis with an endothelial cell surface. These data suggest that balloon-expandable stainless steel stents provide excellent acute and short-term relief of coarctation in this experimental model. Larger and longer-term studies are needed to better assess the incidence of restenosis or aneurysm formation following stenting of coarctation of the aorta.

Angiography↗
PubMed1993

Thoracic cardiovascular anomalies in children: evaluation with a fast gradient-recalled-echo sequence with cardiac-triggered segmented acquisition.

A fast gradient-recalled-echo sequence with cardiac-triggered segmented acquisition (fastcard) was compared with a standard T1-weighted spin-echo sequence with cardiac gating and respiratory compensation in the evaluation of pediatric patients with thoracic cardiovascular anomalies. Twenty patients aged 1 week to 24 years (median age, 9 months) with various abnormalities underwent magnetic resonance (MR) imaging. In 18 patients, MR imaging was performed with both gated spin-echo and fastcard. Two observers rated the clinical utility of each sequence. Fastcard images were superior to spin-echo images in 10 patients, equivalent in seven, and inferior in one. Two additional patients with suspected pulmonary vascular lesions were accurately evaluated with the fastcard technique. The fastcard technique provides superior demonstration of thoracic cardiovascular structures and turbulent flow and enables imaging in multiple phases of the cardiac cycle.

Adolescent↗
PubMed1993

Transcatheter occlusion of patent ductus arteriosus with Gianturco coils.

BACKGROUND: Transcatheter occlusion with Gianturco coils has been attempted in a small number of patients with tiny (< or = 1.5-mm diameter) patent ductus arteriosus, and preliminary results have been encouraging. The present study extends this method to larger ductus sizes and makes recommendations for proper coil size selection. METHODS AND RESULTS: Coil occlusion was attempted in 24 consecutive patients with patent ductus arteriosus who did not require other cardiac surgery. Median patient age was 4.2 years (8 months to 30 years), and mean ductus diameter was 1.7 +/- 0.8 mm. Two instances of coil embolization occurred in the first 4 patients, with successful coil retrieval. Based on this experience, we proposed that the coil helical diameter should be twice or more the minimum ductus diameter, with coil length sufficient for three or more loops. With these recommendations, coils were successfully implanted in the subsequent 20 consecutive patients. Of the 22 patients with successful coil implantation, 15 (68%) had no residual shunting, and 7 had trace residual shunting by angiography. The continuous murmur was abolished in all 22 patients. No significant complications occurred, and all patients were discharged within 24 hours of successful coil implantation. No change in the systolic pressure gradient between main and left pulmonary artery or ascending and descending aorta was observed. CONCLUSIONS: Transcatheter occlusion of patent ductus arteriosus can be safely and effectively achieved in patients with ductus diameters up to 3.3 mm. Coil occlusion does not cause obstruction to flow in the left pulmonary artery or descending aorta. Coils should be selected to provide a helical diameter twice or more the minimum ductus diameter and a length sufficient for three or more loops.

Cardiac Catheterization↗
PubMed1993

Intraoperative and percutaneous stenting of congenital pulmonary artery and vein stenosis.

BACKGROUND: Conventional surgical or balloon dilation therapy for pulmonary artery or vein stenosis has been unsatisfactory in many patients. Balloon-expandable stents offer a new form of treatment for these vascular stenoses and can be implanted percutaneously or intraoperatively. METHODS AND RESULTS: Between July 1991 and October 1992, 20 balloon-expandable Palmaz stents (Johnson & Johnson) were implanted in 16 children at median age and weight of 3.0 years and 12.8 kg, respectively. Stent implantation was performed intraoperatively (n = 15) if the patient was less than 1 year of age or less than 10 kg in weight, in cases where limited vascular access precluded percutaneous implantation, or as an adjunct to other intracardiac surgery. Otherwise, percutaneous stenting was performed (n = 5). Vessels were tested for distensibility by dilation with balloon catheters or vascular sounds. Stents were implanted using angioplasty catheter balloons chosen to achieve desired vessel diameter and inflated to 4 to 17 atm. Acute hemodynamic and cineangiographic studies were performed in all patients immediately after the procedure to 2 months after stenting. After pulmonary artery stent implantation, mean pulmonary artery diameter increased from 5.6 to 11.5 mm (P = .001), with a decrease in mean systolic pressure gradients from 43 to 8.0 mm Hg (P = .005). Follow-up cardiac catheterization (mean, 8.7 months) in 3 patients revealed no restenosis, thrombosis, or aneurysm formation. In patients in whom pulmonary vein stents were implanted, mean pressure gradients fell from 11 to 0.3 mm Hg (P = .03), and mean pulmonary capillary wedge pressure fell from 17 to 6.3 mm Hg (P = .03) immediately after stenting. At 2- to 6-month follow-up, cardiac catheterization documented restenosis within the stent in 2 of 3 patients. The third patient died 2 months after stenting from presumed vein reocclusion. CONCLUSIONS: When implanted intraoperatively or percutaneously, balloon-expandable endovascular stents have been efficacious in the treatment of pulmonary artery stenosis. Longer follow-up will be necessary to document the long-term effectiveness of pulmonary artery stenting. Preliminary data suggest that early restenosis is common after pulmonary vein stenting. The intraoperative approach extends stenting therapy to smaller children and to patients who have limited percutaneous access.

Angioplasty, Balloon↗
PubMed1993

Correction of total anomalous pulmonary venous connection in infancy.

From January 1985 through January 1993, 41 patients less than 1 year of age underwent operative correction of isolated total anomalous pulmonary venous connection. There were 24 boys and 17 girls. The median age at operation was 13 days (range 1 to 282 days) and weight was 3.6 kg (2.5 to 5.2 kg). Locations of the connections were supracardiac in 19, cardiac in 9, infracardiac in 11, and mixed supracardiac and cardiac in 2. Obstruction of the pulmonary veins was severe in 24, mild in 3, and absent in 14. Preoperative stabilization included mechanical ventilation for 15 patients for a mean duration of 2 1/2 days and extracorporeal membrane oxygenation for 1 patient for 1 day. All operations were performed with deep hypothermia and circulatory arrest (mean arrest time 34 minutes). Supracardiac connections were repaired by performing a side-to-side anastomosis between the pulmonary venous confluence and the dome of the left atrium through a superior approach between the superior vena cava and the aorta. Coronary sinus connections were repaired by enlarging the atrial septal defect and the coronary sinus communication with the left atrium and closing the atrial defect with a large patch. Infracardiac repairs included elevation and rotation of the heart to the right and an elongated side-to-side anastomosis between the common venous confluence and the left atrium. One patient died 1 week postoperatively of persistent pulmonary hypertension. Another patient, who was supported by extracorporeal membrane oxygenation before the operation, died 3 months after the operation as a consequence of pulmonary lymphangiectasia. All other patients are alive and well with a mean follow-up of 26 months (range 3 to 77 months). One patient required two subsequent reoperations for persistent pulmonary venous obstruction, and another patient had superior vena cava obstruction necessitating reoperation. Operative treatment of total anomalous pulmonary venous connection in infants can be performed with low mortality and an infrequent need for reoperations.

Cardiac Surgical Procedures↗