Analysis of the US Food and Drug Administration Manufacturer and User Facility Device Experience database for adverse events involving Amplatzer septal occluder devices and comparison with the Society of Thoracic Surgery congenital cardiac surgery database

ObjectiveAmplatzer (AGA Medical Corporation, Plymouth, Minn) septal and vascular occluder devices have significantly altered the care of patients with congenital heart disease. The relative frequency and consequence of complications resulting from the attempted placement of such devices, however, have not been well assessed. The purpose of this study is to use large databases to assess the frequency and severity of such complications and compare them with those of surgical atrial septal defect closure.MethodsThe US Food and Drug Administration Manufacturer and User Facility Device Experience database was quarried for all adverse events for Amplatzer septal occluder devices, which were categorized and analyzed with particular emphasis on management and outcome. The Society of Thoracic Surgery database was likewise quarried for the same data regarding atrial septal defect closures over a contemporaneous time period. By using a literature-derived denominator for total Amplatzer implant numbers, the results of the 2 therapies were compared.ResultsSince July 1, 2002, 223 adverse events in patients undergoing Amplatzer atrial septal defect closure were submitted to the Food and Drug Administration, resulting in 17 deaths (7.6%) and 152 surgical rescue operations (68.2%). Society of Thoracic Surgery data demonstrated 1537 primary operations with 2 deaths (0.13%) and 6 reoperations (0.39%). By extrapolating on published estimates of Amplatzer implantation to provide an implant denominator (n = 18,333), there was no difference between overall mortality for surgical (0.13%) and device closure (0.093%, P = .649). Rescue operation for device adverse events (0.83%) was 2.1 times more likely than reoperation for surgical closure (0.39%, P = .063). Mortality per adverse event was higher for device closure (7.6%) than for surgical closure (1.2%, P = .004), and the need for surgery per adverse event was higher for device closure (68.2%) than for surgical closure (3.6%, P < .001). The mortality for surgical management of a device adverse event (2.6%) was 20-fold higher than for primary elective atrial septal defect closure (0.13%, P < .0001).ConclusionOverall crude mortality for device and surgical closure atrial septal defect closure is equivalent, and the need for subsequent operation (surgical rescue) is more common in patients undergoing device closure than reoperation is in patients undergoing surgical closure. Complications from device closure tend to be serious and most often require urgent or emergency operative management, whereas the mortality for surgical management of a device complication appears higher than that of elective atrial septal defect closure. Further information is required in the form of postmarketing surveillance, such as a mandatory user registry with periodic end-user notification

Geometric mismatch of pulmonary and aortic anuli in children undergoing the Ross procedure: Implications for surgical management and autograft valve function

AbstractBackground: There is often substantial mismatch between the diameters of the pulmonary and aortic anuli in young patients with systemic outflow tract disease. To implant the autologous pulmonary valve in the aortic position under such circumstances, it is necessary to adapt the geometry of the systemic outflow tract. The effects of such adaptations on autograft function in children are not well known. Methods: To determine factors predictive of autograft regurgitation, we analyzed 41 cases of children who have undergone the Ross procedure. The diameter of the pulmonary valve was greater (by at least 3 mm) than that of the aortic valve in 20 cases, equal (within 2 mm) in 12 cases, and less (by at least 3 mm) in nine cases, with differences ranging from +10 to –12 mm. In 12 patients with a larger pulmonary anulus, aortoventriculoplasty was used to correct the mismatch. In patients with a larger aortic anulus, the mismatch was corrected by gradual adjustment along the circumference of the autograft, rather than by tailoring of the native aortic anulus. Results: At follow-up (median 31 months), two patients had undergone reoperation on the neoaortic valve for moderate regurgitation. In the remaining 38 cases, autograft regurgitation was as follows: none or trivial in 30, mild in seven, and moderate in one. There was no correlation between regurgitation and age, geometric mismatch, or previous or concurrent procedures. Conclusions: Subtle technical factors that may result in distortion of the valve complex are probably more important determinants of autograft regurgitation than are indication for repair, geometric mismatch, or previous or concomitant outflow tract procedures. Significant mismatch of the semilunar anuli is not a contraindication to the Ross procedure in children. (J Thorac Cardiovasc Surg 1998;115:1255-63

Validation of Immersed Boundary Simulations of Heart Valve Hemodynamics against In Vitro 4D Flow MRI Data

The immersed boundary (IB) method is a mathematical framework for fluid-structure interaction problems (FSI) that was originally developed to simulate flows around heart valves. Validation of FSI simulations around heart valves against experimental data is challenging, however, due to the difficulty of performing robust and effective simulations, the complications of modeling a specific physical experiment, and the need to acquire experimental data that is directly comparable to simulation data. In this work, we performed physical experiments of flow through a pulmonary valve in an in vitro pulse duplicator, and measured the corresponding velocity field using 4D flow MRI (4-dimensional flow magnetic resonance imaging). We constructed a computer model of this pulmonary artery setup, including modeling valve geometry and material properties via a technique called design-based elasticity, and simulated flow through it with the IB method. The simulated flow fields showed excellent qualitative agreement with experiments, excellent agreement on integral metrics, and reasonable relative error in the entire flow domain and on slices of interest. These results validate our design-based valve model construction, the IB solvers used and the immersed boundary method for flows around heart valves

Latest development of a W-band Gyro-TWA based on a helically corrugated interaction region

Latest development and experimental study of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented. With an input seed signal from an 1.5 W, 90-96 GHz solid state source a gain of 27 dB was measured from the experiment. The bandwidth of the gyro-TWA was measured to be at least 5 GH

Measurement of a W-band gyro-TWA experiment based on a helically corrugated interaction region

Measurements of an upgraded W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented. With upgraded input coupler and output systems a gain of ~37 dB was measured from the experiment with a maximum output power of over 2 kW. The amplification from the gyro-TWA was measured in the frequency range of 90 GHz to 96 GHz

Developments of a W-band gyro-TWA for high PRF operation

Latest developments of a gyrotron travelling wave amplifier (gyro-TWA) with a helically corrugated waveguide and a cusp electron gun for operation over a bandwidth of 90-100 GHz at a high pulse repetition rate (5 kHz) are presented. Performance upgrades of the input coupler, pulsed power system and beam collector with water-cooling capability were realized for the high power wide band gyro-TWA

Hemidiaphragmatic paralysis increases postoperative morbidity after a modified Fontan operation

AbstractObjectives: After a Fontan procedure, forward pulmonary blood flow is augmented during inspiration because of negative intrathoracic pressure. Total pulmonary blood flow is higher during inspiration. With hemidiaphragmatic paralysis, inspiratory augmentation of pulmonary flow is lost or diminished. The objective of this study was to compare early postoperative morbidity after the modified Fontan operation in patients with and without hemidiaphragmatic paralysis. Methods: A case-control analysis was performed comparing 10 patients with documented hemidiaphragmatic paralysis against 30 patients without paralysis who were matched for diagnosis, fenestration, and age. The following early postoperative outcomes were assessed: duration of ventilator support, duration of hospital stay, incidence of ascites, prolonged effusions, and readmission. Results: Preoperatively, there were no significant differences between the 2 groups. However, among the postoperative outcomes, the duration of hospital stay (25.4 ± 16.6 days vs 10.8 ± 6.3 days; P =.03), incidence of ascites (70% vs 3%; P ||.001), prolonged pleural effusions (60% vs 13%; P =.007), and readmission (50% vs 7%; P =.007) were significantly greater in patients with hemidiaphragmatic paralysis than in those without hemidiaphragmatic paralysis. Conclusions: Hemidiaphragmatic paralysis after the modified Fontan operation is associated with an increase in early morbidity. Care should be taken to avoid injury to the phrenic nerve. Patients with prolonged effusions should be evaluated for hemidiaphragmatic paralysis.J Thorac Cardiovasc Surg 2001;122:856-6

Design and experiment of a broadband W-band gyro-TWA based on a helically corrugated interaction region

The design and experiment of an upgraded W-band gyrotron travelling wave amplifier (gyro-TWA) based on a helically corrugated interaction region is presented. The upgrade of the input coupler, output window, corrugated output mode converter enabled a measured output power of a few kWs from the gyro-TWA with an unsaturated gain of up to 40 dB and a 3 dB frequency bandwidth of at least 5.5 GHz

High pulse repetition frequency operation of a W-band Gyro-TWA based on a cusp electron beam source

The components of a W-band gyro-TWA including input coupler, output window, corrugated output mode converter, pulsed power system and water-cooled beam dump are being upgraded to achieve an output power of 5 kW and a high pulse repetition rate of 2 kHz for cloud radar applications. Latest results of the W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented

Further experiments of a W-band gyro-TWA based on a helically corrugated interaction region

Latest results of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun for operation at a high pulse repetition rate are presented. Performance upgrades of input coupler, output window, corrugated horn, pulsed power system and beam collector with water-cooling capability were realized. With an input seed signal from an 1.5 W, 90-96 GHz solid state source the amplification gain and minimum bandwidth were measured from the experiment