Publications (15)40.19 Total impact
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Article: Transcatheter closure of the perimembranous ventricular septal defect-preclinical trial of a new Amplatzer device.
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ABSTRACT: This study assessed the feasibility and efficacy of implanting a new nitinol device for closure of perimembranous ventricular septal defects in a swine model. Perimembranous ventricular septal defect occurs in 80% of patients requiring treatment for congenital heart disease. The Amplatzer perimembranous ventricular septal occluder device (pmVSO2 device, AGA Medical Company, Plymouth MN) is a new transcatheter Nitinol device containing polyester fabric designed to close the perimembranous ventricular septal defect (VSD). The device has 75% reduction in radial force, 45% reduction in clamping force, and increased stability as compared to the previous version. The device was implanted in six swine with naturally occurring perimembranous VSD with immediate, 1, 7, ∼30, and ∼90 day followup by echocardiography, angiography, and final pathological examination. The device was successfully implanted in all animals and was retrievable and repositionable. There was complete occlusion of the VSD in five of six cases without embolization. There was no thrombus formation on the device or occurrence of complete heart block. A single instance of a tiny residual shunt was attributed to capture of tricuspid valve apparatus. The success of this animal study confirms safety and feasibility of the Amplatzer pmVSO2 device. Human trials are planned.Catheterization and Cardiovascular Interventions 12/2011; 79(7):1153-60. · 2.29 Impact Factor -
Article: Transcatheter occlusion of the patent ductus arteriosus in infants - experimental testing of a new amplatzer device.
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ABSTRACT: OBJECTIVES:: This study assessed the feasibility and efficacy of implanting a new miniaturized nitinol device to occlude the patent ductus arteriosus (PDA) in a newborn porcine model. BACKGROUND:: Transcatheter device closure is the standard of care for PDA in older children and adults. Currently available technology is not designed for the newborn infant. METHODS: The Amplatzer Duct Occluder II 0.5 is a new transcatheter Nitinol device without fabric designed to close the PDA with small aortic and pulmonary artery structures. The device was implanted in 8 infant pigs (average weight 2400 gm) after balloon dilation of PDA (average diameter 2.7mm, average length 5.8mm) with immediate, ∼7, ∼30 and ∼90 day follow-up by echocardiography, angiography and final pathological examination. Half were implanted arterial, and half venous. RESULTS:: The device was successfully implanted in all animals. There was complete occlusion of the PDA in all cases without obstruction of the pulmonary arteries or aorta. There was complete late endothelialization without thrombus. The only complication was transection of a femoral artery accessed by cutdown. CONCLUSIONS: The success of this animal study confirms safety and feasibility of the Amplatzer Duct Occluder II 0.5 (now known as the ADO II AS) for use when the aorta and pulmonary arteries are small. Consideration can be given to transcatheter closure of the PDA in preterm and other small infants with this device. © 2011 Wiley-Liss, Inc.Catheterization and Cardiovascular Interventions 01/2011; · 2.29 Impact Factor -
Article: Transcatheter occlusion of the left atrial appendage--experimental testing of a new Amplatzer device.
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ABSTRACT: This study assessed the feasibility and efficacy of implanting a new nitinol device in the left atrial appendage (LAA) in a canine model. Left atrial thrombus occurs in the LAA in 90% of humans with nonvalvular atrial fibrillation (AF). The Amplatzer Left Atrial Appendage Occluder Device now known as the Amplatzer Cardiac Plug (Amplatzer Medical LLC, Plymouth MN) is a new transcatheter Nitinol device containing polyester fabric designed to seal the LAA. The device was implanted in 10 canines with immediate, approximately 30 and approximately 90-day follow-up by echocardiography, angiography, and final pathological examination. The device was successfully implanted in all animals and found to be retrievable and repositionable. There was complete occlusion of the LAA in all cases without embolization. There was no thrombus formation on the device and no pericardial effusion or impingement on the circumflex coronary artery, mitral valve, or left pulmonary vein. A single instance of tiny left atrial mural thrombus at device end screw contact was attributed to the small canine left atrium. The success of this animal study confirms safety and feasibility of the Amplatzer Cardiac Plug. Human trials are warranted.Catheterization and Cardiovascular Interventions 08/2010; 76(2):181-5. · 2.29 Impact Factor -
Article: Echocardiographic assessment of ductal anatomy in premature infants-lessons for device design.
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ABSTRACT: Echocardiographic analysis of patent ductus arteriosus (PDA), proximal left main pulmonary artery (LPA) and descending thoracic aorta (Ao) dimensions in preterm infants who undergo surgical ligation of the PDA. A discussion for percutaneous ductal occlusion in preterm infants. Echocardiographic analysis of the LPA diameter, PDA diameter, PDA length, and descending thoracic aorta diameter in 55 preterm infants who underwent surgical ligation of the PDA from 2004 to 2008. Patients were stratified by weight into four groups: those less than 750 g, 751-1,000 g, 1,001-1,250 g, and those greater than 1,250 g. Mean and standard deviation for each structure dimension was calculated in each weight group. Structural dimensions were compared between groups using ANOVA for multiple comparisions. The mean patient weight was 1,018 g (560-2,400 g). The mean ductal length was 4.1 mm (2.5-5.3 mm). The mean ductal diameter was 2.2 mm (1.5-3.6 mm). The mean LPA diameter was 3 mm (1.5-4.5 mm). The mean aortic diameter was 4.3 mm (2.7-7.8 mm). The alpha value for between weight groups for PDA length was 0.21, PDA diameter 0.16, LPA diameter 0.39, and aortic diameter 0.1. No statistical significance was seen when comparing structure dimension by weight. This suggests uniform structural dimensions across a broad weight distribution in this patient population. To date, there has been no attempt to standardize dimensions of these vascular structures. The information gathered in this study may be useful in developing an implantable device for ductal occlusion in preterm infants. (ECHOCARDIOGRAPHY 2010;27:575-579).Echocardiography 03/2010; 27(5):575-9. · 1.24 Impact Factor -
Article: PFO closure complications from the AGA registry.
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ABSTRACT: To evaluate all complications that occurred during or after cardiac catheterizations for Amplatzer PFO device closure of patent foramen ovale (PFO), determine the cause of the complications and recommend techniques to minimize complications in the future. Rare complications were reported to the manufacturer of the Amplatzer PFO occluder since the introduction of the device. A panel of independent physicians reviewed all complications reported to the manufacturer to determine whether the complication was related to the device or related to the cardiac catheterization procedure. Demographic data, echocardiograms, operative reports, and time to occurrence of complications were reviewed. A total of 11 events were reported. Only two patients had device related complications (erosion), an incidence of 0.018%. Two patients were found to have additional atrial septal defect after PFO closure. Two patients were thought to have an inflammatory reaction without any serious sequelae. Five complications were related to the cardiac catheterization procedure (atrial appendage perforation). Device related complications after Amplatzer PFO occluder placement are extremely rare. Cardiac catheterization related complications appear to be the most common cause of the hemodynamic compromise. Careful manipulation of catheters and wires, recognition of the location of the catheter by fluoroscopy and echocardiography will decrease the risk of such complications.Catheterization and Cardiovascular Interventions 08/2008; 72(1):74-9. · 2.29 Impact Factor -
Article: Percutaneous closure of a large PDA in a 35-year-old man with elevated pulmonary vascular resistance.
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ABSTRACT: The presence of a large patent ductus arteriosus (PDA) may result in significant pulmonary hypertension, which may not be reversible. We present the case of a 35-year-old man with pulmonary hypertension who had successful percutaneous closure of a large PDA with an Amplatzer muscular ventricular septal defect occluder and resolution of his pulmonary hypertension. The use of prior balloon test occlusion of the PDA suggested that the procedure would be successful, despite the lack of an immediate fall in the pulmonary artery pressure.Congenital Heart Disease 04/2008; 3(2):149-54. · 0.90 Impact Factor -
Article: Permanent pacemaker for atrioventricular conduction block after operative repair of perimembranous ventricular septal defect.
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ABSTRACT: This study sought to discover the incidence of permanent pacemaker (PPM) placement for atrioventricular conduction block (AV block) after operative repair of perimembranous ventricular septal defect (PMVSD) in a large multi-institutional database and in the subgroup of patients comparable to those considered for transcatheter device closure of PMVSD. Atrioventricular conduction block is a complication of operative repair of PMVSD and of device closure of this defect. Earlier reports do not report the incidence of AV block by VSD type. The Pediatric Cardiac Care Consortium database was searched for all children who had operative PMVSD repair except those with abnormalities that increase risk of AV block. The patient group was searched for those with subsequent PPM placement for AV block. Demographic data and time to PPM placement were available for all patients. Of 4,432 patients with PMVSD repair, 48 (1.1%) underwent PPM placement for AV block. The PPM group was more likely to have Down syndrome (41% vs. 18%; p < 0.001), was younger (mean age 14 vs. 26 months; p < 0.001), and had longer mean length of postoperative hospital stays (20 vs. 8 days; p < 0.001). The most significant risk factor for AV block was Down syndrome (odds ratio 3.62, 95% confidence interval 2.02 to 6.39; p < 0.005). Modal time to PPM placement was 7 days (range 0 to 4,078 days). Out of 1,877 patients comparable to those currently considered for device closure, 13 (0.8%) underwent PPM placement after PMVSD repair. Operative AV block and PPM placement occurred in 1.1% of patients in the total group and in 0.8% of patients comparable to those considered for device closure of PMVSD. A PPM placement is more likely in patients with Down syndrome. These data should be considered as devices are developed and in the future when counseling families about options for PMVSD closure.Journal of the American College of Cardiology 09/2007; 50(12):1196-200. · 14.16 Impact Factor -
Article: Initial experience with the Amplatzer membranous septal occluder in adults.
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ABSTRACT: Most perimembranous ventricular septal defects (pmVSD) that are still patent in adult life are small, hemodynamically and clinically unimportant, and do not require any intervention. However, surgery in adulthood for those that need to be closed carries significant morbidity. A trans-catheter technique for closing pmVSDs has been developed, and this paper describes our initial experience using the Amplatzer membranous septal occluder (AMSO). Twelve patients, 9 female and 3 male, median age 34.5 years (range: 21-67) underwent catheterization for attempted pmVSD closure. Ten of the defects were native and 2 were post-operative residual defects. Transcatheter VSD closure was performed as previously described, under general anesthesia and with trans-esophageal echocardiographic (TEE) monitoring. Patients had a moderate to large left to right shunt (mean Qp/Qs = 2.0+/-0.4) with mild left heart volume overload and near normal pulmonary pressure. All 10 native pmVSDs were closed successfully, 9 with AMSO and one with an Amplatzer muscular VSD occluder, after failure to implant the AMSO. There was one post procedural complication--self-limiting retroperitoneal bleeding. Three patients had a residual leak. Attempted VSD closure in the 2 patients with post surgery residual shunt was unsuccessful. We conclude that transcatheter mVSD closure with the AMSO is an efficient and safe alternative to surgery in carefully selected adult patients with native pmVSDs.Acute Cardiac Care 02/2007; 9(1):54-9. -
Article: Transesophageal echocardiography guidance for repair of complex cardiac injuries.
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ABSTRACT: Our patient suffered a single stab wound to the heart that resulted in a coronary artery to ventricle fistula, a ventricular septal defect, mitral regurgitation from chordal transection, and a delayed left ventricular aneurysm. We used transesophageal echocardiography to characterize these multiple defects to help guide successful surgical repair. The patient recovered uneventfully.The Annals of thoracic surgery 01/2007; 82(6):2289-92. · 3.74 Impact Factor -
Article: Transcatheter closure of large secundum atrial septal defects using the 40 mm Amplatzer septal occluder: results of an international registry.
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ABSTRACT: Little is known about the efficacy and safety of the 40 mm Amplatzer septal occluder (ASO). Thirty-three patients (22 female, 11 male) with a large secundum atrial septal defect (ASD) underwent attempted device closure using the 40 mm ASO at a median age of 40 years (range, 14-81 years) and median weight of 65 kg (range, 48-98 kg). The median size of the ASD measured on 2D transesophageal echocardiography (27 patients) or intracardiac echocardiography (6 patients) was 30.5 mm (range, 24-39 mm) and the median balloon-stretched diameter was 37.7 mm (range, 32-43.7 mm). The median Qp:Qs ratio was 3.2:1 (range, 1.4-6.2). The attempt was unsuccessful in five patients; two had device embolization and one had left atrial wall perforation due to the sheath; all three required emergent surgery. The attempt was successful in the 28 remaining patients, resulting in complete immediate closure in 14 and a trivial residual shunt in 14. Fluoroscopy time ranged from 8.6 to 37.8 min (median, 12.2 min). At 24-hr follow-up, 2D transthoracic echocardiography with color flow Doppler revealed complete closure in 23 patients, and 5 had a trivial residual shunt. There were no complications encountered in patients who received the device. On follow-up, all patients are doing well. We conclude that the 40 mm ASO is safe and effective in most patients with a large ASD up to a diameter of 39 mm. However, the use of this device requires careful attention as the procedure may be unsuccessful or the device may embolize.Catheterization and Cardiovascular Interventions 01/2006; 66(4):580-4. · 2.29 Impact Factor -
Article: Erosion of Amplatzer septal occluder device after closure of secundum atrial septal defects: review of registry of complications and recommendations to minimize future risk.
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ABSTRACT: The objectives of this study were to identify possible risk factors that may lead to erosion of the Amplatzer septal occluder (ASO) and recommend ways to minimize future risk. There have been rare occurrences of adverse events with development of pericardial effusion after ASO placement. Identification of high-risk cases, early recognition, and prompt intervention may minimize the future risks of adverse events. In all patients who developed hemodynamic compromise after ASO placement, echocardiograms (pre-, intra-, and postprocedure), atrial septal defect (ASD) size (nonstretched, stretched), size of the device used, cineangiograms, and operative records were reviewed by a panel selected by AGA Medical Corporation. The findings were compared to the premarket approval data obtained from FDA-approved clinical trials that were conducted in the United States, before the device was approved. A total of 28 cases (14 in United States) of adverse events were reported to AGA Medical. All erosions occurred at the dome of the atria, near the aortic root. Deficient aortic rim was seen in 89% and the defect described as high ASD, suggesting deficient superior rim. The device to unstretched ASD ratio was significantly larger in the adverse event group when compared to the FDA trial group. The incidence of device erosion in the United States was 0.1%. The risk of device erosion with ASO is low and complications can be decreased by identifying high-risk patients and following them closely. Patients with deficient aortic rim and/or superior rim may be at higher risk for device erosion. Oversized ASO may increase the risk of erosion. The defect should not be overstretched during balloon sizing. Patients with small pericardial effusion at 24 hr should have closer follow-up.Catheterization and Cardiovascular Interventions 01/2005; 63(4):496-502. · 2.29 Impact Factor -
Article: Usefulness of bone marrow transplantation in the Hurler syndrome.
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ABSTRACT: The Hurler syndrome, an autosomal recessive storage disease of childhood, leads to death within the first decade of life from progressive deposition of glycosaminoglycans within the myointima of the coronary arteries and airways. Cardiac ultrasound findings of patients with this syndrome >10 years after successful bone marrow transplantation are described.The American Journal of Cardiology 10/2003; 92(7):882-6. · 3.37 Impact Factor -
Article: Initial human experience with the Amplatzer perimembranous ventricular septal occluder device.
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ABSTRACT: Transcatheter closure of perimembranous ventricular septal defects with coils or devices designed to close other lesions may be complicated by embolization or aortic insufficiency. A new asymmetric Amplatzer perimembranous ventricular septal occluder and delivery system was specifically designed for perimembranous defects. This report describes the first use of this device in 27 patients. Implantation was successful in 25 (93%), with 1 removed for device-related aortic insufficiency and inability to position the delivery sheath in another. Device orientation was excellent when the device was initially advanced through a standard delivery sheath positioned in the left ventricular apex. Twenty-three had complete occlusion within 1 week (92%), with a tiny (< 2 mm) residual shunt in the other two. In the 25 subjects with the device left in place, device-related aortic or tricuspid insufficiency, arrhythmias, and embolization were not observed. These excellent acute results need to be confirmed by long-term follow-up.Catheterization and Cardiovascular Interventions 02/2003; 58(2):238-45. · 2.29 Impact Factor -
Article: Corrosive behaviour of Amplatzer devices in experimental and biological environments.
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ABSTRACT: Nitinol, a nickel-titanium alloy, is a valuable material in the construction of interventional endoluminal devices because of its biocompatibility, super elasticity, high resiliency and shape memory. The possibility of nickel toxicity has been raised with devices constructed of Nitinol. Our investigation examines the long-term corrosive behavior of this alloy in experimental and biological environments. We performed three levels of study. Microscopic examination was made of 64 devices of various sizes, randomly selected from 240 Amplatzer Septal Occluders that had been exposed to saline solution at 37 degrees C for fourteen months. All samples were studied by electron microscopy ranging from 50 to 5000 times magnification. We also studied microscopically 3 Amplatzer devices explanted 18-36 months after implantation in dogs, and 2 Amplatzer Septal Occluders removed from patients 18 months (cardiac transplant) and 19 months (died of causes unrelated to device placement) after implantation, which were examined grossly and by electron microscopy up to 5000 times magnification. We then measured the levels of nickel in the blood using inductive plasma mass spectroscopy in 19 patients with implanted Amplatzer devices, making measurements before and 6 months after implantation. Electron microscopy showed an intact titanium oxide layer with no evidence of corrosion in vitro and in vivo. One explanted device in direct contact with the platinum leads of a pacemaker for eighteen months showed minor pitting of the titanium oxide layer believed to be galvanic in nature. No wire fractures were found in vitro after cycle testing with 400 million cycles, nor in devices taken from the animals and humans. Biochemical studies showed no significant elevation of levels of nickel levels after implantation. Nitinol wire of Amplatzer septal occlusion devices is resistant to corrosion when exposed to physiologic saline solution, and in experimental animals as well as humans. A device in contact with a platinum pacemaker electrode developed minimal pitting of the titanium oxide layer, believed to be galvanic in nature and of no structural or clinical significance. There is no increase of concentrations of nickel in the blood of patients who have received Amplatzer nitinol devices. These favorable testing results reveal that nickel-titanium is an inert, corrosion resistant alloy.Cardiology in the Young 06/2002; 12(3):260-5. · 0.76 Impact Factor -
Article: Parastemal cross-sectional echocardiographic determination of aortic arch situs: A new approach
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ABSTRACT: Determination of the situs of the aortic arch is extremely important in the complete evaluation of infants with congenital heart disease, as well as in infants with esophageal atresia and tracheoesophageal fistula in whom the thoracotomy incision is performed contralateral to the aortic arch.1 Definitive determination of the side of the aortic arch can be made angiographically, but this is invasive and requires transport of the infant. The thoracic roentgenogram is not always reliable in determining aortic arch situs, particularly in newborns. Computed tomography of the thorax has also been used,2 but tomographs are not portable. Evaluation of the aortic arch from the suprasternal notch using cardiac ultrasound has been reported.3–6 In most studies, the sector orientation required for a long-axis image of the arch was used to distinguish situs.3–5 The position of the descending thoracic aorta also has been used to infer the side of the aortic arch.4–5 These techniques are subjective and depend on the skill of the operator. They do not provide for a descending aorta contralateral to the aortic arch with retroesophageal segment, nor for cardiac malpositions. The relative positions of the esophagus and aortic arch have also been used to identify the side of the arch,6 but this technique is not useful with esophageal atresia. We therefore devised a new technique to evaluate aortic arch situs from a parasternal short-axis approach.The American Journal of Cardiology.
Top co-authors
Top Journals
Institutions
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2010–2011
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Children's Hospitals and Clinics of Minnesota
Minneapolis, MN, USA
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2003–2011
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University of Minnesota Duluth
Duluth, MN, USA
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2008
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University of Wisconsin, Madison
Madison, MS, USA
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2002
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University of Minnesota Twin Cities
- Department of Radiology
Minneapolis, MN, USA
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