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Comparison of percutaneous closure of large patent ductus arteriosus by multiple coils versus the Amplatzer duct occluder device.

This study compared the efficacy and costs of the most used approaches for percutaneous closure of large patent ductus arteriosus, that is, multiple coils and the Amplatzer duct occluder (ADO) device. From April 2000 to September 2003, 47 patients underwent closure of large, symptomatic patent ductus arteriosus (diameter 4.6 +/- 3.0 mm/m(2); QP/QS 2.1 +/- 1.9) with multiple Cook detachable coils (n = 19) or the ADO device (n = 28). The multiple coil approach was significantly cheaper (1,389 +/- 168 vs 3,811 +/- 38, p <0.0001) but as effective as the ADO device over a mid-term follow-up (occlusion rate 89.5% vs 96.4%, p = NS).

Adolescent↗

Clearing a path through the patent thicket.

Patents do not always promote innovation, particularly when they restrict access to fundamental scientific discoveries and the tools of basic research. However, there are legal and policy approaches that may help to ameliorate problems associated with patenting these sorts of inventions.

Diffusion of Innovation↗

Product patents on human DNA sequences: where do we stand in Europe?

In July 1998, the Directive 98/44/EC was adopted by the competent European Community bodies. It should have been implemented into national laws of the member states by the end of July 2000. So far, however, most member states missed that deadline. One reason for resistance and hesitations are concerns about potential negative effects of product patents based on gene sequences. Reasons for this situation are analysed and solutions sought for minimising the prospects of increasing dependencies on dominant patents on genes.

Base Sequence↗

Rational and efficient geometric definition of pharmacophores is essential for the patent process.

The geometric description of pharmacophores suffers from approximations. No consensus has been clearly established, despite the increasing interest in using pharmacophores in drug design and in patent applications. We therefore propose an original definition of a pharmacophore using spherical coordinates. These coordinates give a precise description of each point using three parameters: distance to a geometric origin and two angles. If necessary, these parameters can be easily and rapidly converted to cartesian coordinates. Our method can guarantee, to the patent applicant, the safe protection of his intellectual property by both improving markedly the readability of a pharmacophore definition and bringing, to the person who is skilled in the art, enough information to understand easily the essence of the invention.

Computer-Aided Design↗

Cor triatriatum associated with severe valvular pulmonary stenosis and patent ductus arteriosus: an unreported constellation.

A divided left atrium because of cor triatriatum is a relatively rare cardiac anomaly requiring corrective surgery. Although association of cor triatriatum with different congenital heart diseases had been reported, to our knowledge, its association with severe valvular pulmonary stenosis and patent ductus arteriozus had not been reported previously. In this paper, an asymptomatic case with cor triatriatum, severe valvular pulmonary stenosis and patent ductus arteriosus is defined.

Child↗

Comparison of suture ligation and clip application for the treatment of patent ductus arteriosus in preterm neonates.

OBJECTIVE: We reviewed the experience of 2 centers performing surgical ligation of patent ductus arteriosus in preterm neonates to identify whether the choice of surgical technique--suture ligation or clip application--affected outcome. METHODS: Between 2000 and 2005, 67 newborn infants had open surgical closure of patent ductus arteriosus: 33 by suture ligation and 34 by clip application. The groups were similar in age and sex. RESULTS: The average length of the procedure was 55.8 +/- 13.7 minutes for suture ligation and 30.8 +/- 8.7 minutes for clip application (P < .05). Six neonates had intraoperative bleeding in the suture ligation group. Four patients had significant postoperative complications in the suture ligation group, compared with 2 in the clip application group. CONCLUSIONS: This study demonstrates that clip application results in a significant reduction in the operative time and, possibly, in less morbidity.

Cardiac Surgical Procedures↗

Gene patents, health care policy and licensing schemes.

Human gene patents continue to stir social controversy, including the possibility that they might adversely affect public access to useful technologies. It has been suggested that a compulsory licensing policy might be used to alleviate the adverse effect of patents in this context. We suggest, however, that it is unclear whether existing international policies and licensing practices will permit compulsory licensing to be used in a way that would address common concerns. Indeed, given the minor role that genetic technologies have in most health care systems, it would be difficult to justify compulsory licensing. At a minimum, policy makers need to be more realistic about the potential effects of international trade agreements on the development of biotechnology policies.

Genetic Research↗

Combined noninvasive assessment of the patent ductus arteriosus in the preterm infant before and after indomethacin treatment.

Fifteen preterm infants who weighed 0.7 to 2.0 kg and had clinical evidence of a patent ductus arteriosus (PDA) were studied by combined 2-dimensional and Doppler echocardiography before and after the administration of indomethacin. In 10 patients the PDA was widely patent at the time of the study and in 5 the lumen was narrow. In this latter group, the PDA was narrow at the pulmonary artery end in 2 patients, in the middle in 2 patients and at the aortic end and the middle in 1 patient. After the administration of intravenous indomethacin, the PDA closed completely in 12 patients and constricted in 3. The patterns of closure could be documented in those in whom serial studies were performed. In 3 patients, closure occurred after a single dose of indomethacin, in 3 after 2 doses and in the rest after a full course of 3 doses. Doppler interrogation at the aortic and pulmonary artery end of the PDA demonstrated the shunting patterns and provided a reliable assessment of patency after the ductal lumen was outside the range of lateral resolution following constriction. In no case did the PDA reopen after the course of indomethacin. This combined approach is a reliable method of assessing a PDA before and after a course of indomethacin. It should provide the means to answer many of the questions regarding the effect of various manipulations on the PDA in the preterm infant.

Ductus Arteriosus, Patent↗

Effectiveness of five-loop coils to occlude patent ductus arteriosus.

Coil occlusion of patent ductus arteriosus with 5-loop coils was undertaken in 10 patients without coil embolizations, and with 90% immediate occlusion and 100% occlusion at follow-up. We conclude that 5-loop coil occlusion of patent ductus arteriosus is safe and effective.

Adult↗

Aortic stent-graft for patent ductus arteriosus in adults: the aortic exclusion technique.

The risk of closure of a patent ductus arteriosus in the elderly is high because of the fragility of the aorta and aneurysmal change in the ductus. Stent-grafting has emerged as a method of treatment of pathology of the aorta. We describe a case where this new endovascular technique has been successfully applied for closure of a patent ductus arteriosus in a high-risk patient. It may become part of the armamentarium for this pathology in adults.

Aged↗

Truncus arteriosus with patent ductus arteriosus and normal aortic arch.

In hearts with a common arterial trunk (truncus arteriosus), there is almost always an inverse development of the aortic arch and the ductus arteriosus. Truncus with a normal aortic arch and a patent ductus is a rare echocardiographic and surgical finding. In this report, we describe 2 neonates in whom truncus arteriosus with a normal aortic arch and a medium or large patent ductus was diagnosed by preoperative echocardiography (without catheterization) and confirmed intraoperatively.

Aorta, Thoracic↗

Functional scoliosis as a long-term complication of surgical ligation for patent ductus arteriosus in premature infants.

Follow-up evaluation was performed on two groups of children, all premature infants who had undergone surgical ligation of a patent ductus arteriosus in the first days of life (Group I, 12 months postligation; Group II, 4 years postligation). Overall, two of 11 patients had significant functional scoliosis associated with weakness of shoulder girdle musculature and three additional patients had functional weakness on the affected side but with normal vertebral alignment. Patients post-patent ductus ligation should be observed for this long-term complication.

Ductus Arteriosus, Patent↗

Comparison of muscle-sparing thoracotomy and thoracoscopic ligation for the treatment of patent ductus arteriosus.

PURPOSE: We reviewed our experience with the treatment of patent ductus arteriosus (PDA), and compared two therapeutic techniques; muscle-sparing thoracotomy (MST) and thoracoscopic PDA ligation (TPDAL). METHODS: We reviewed the clinical records and operative reports of 19 nonnewborn patients who were treated at our institution for PDA. Eleven patients underwent TPDAL and eight patients MST. The TPDAL patients underwent thoracoscopic clipping (ligation) of the PDA, whereas the MST group had a complete division of the ductus. A two-tailed Student's t test was used to calculate the 95% confidence intervals for length of operation, number of doses of intravenous narcotics and hospital stay. Costs were also compared. RESULTS: All patients underwent diagnostic echocardiography in the evaluation of an asymptomatic murmur. Both groups were similar in age (average, 4 years) and gender. All procedures were performed electively. Two thoracoscopic attempts were aborted, one for bleeding and the other for inadequate clip size. The length of the procedure averaged 1.3 hours +/- 0.330 SD for TPDAL versus 1.4 hours +/- 0.335 SD for MST. Five of the nine successful TPDAL patients were admitted to the Pediatric Intensive Care Unit (PICU) with an average length of stay of 20 hours, and two of eight MST patients stayed in the PICU for average of 18 hours. All patients were extubated after the procedure. Chest tubes were placed in two TPDAL patients and three MST patients. However, two patients who underwent TPDAL required tube thoracostomy for persistent postoperative pneumothorax. Average number of intravenous narcotics administered for the TPDAL was 1.2 doses per patient and for MST, 1.75 doses per patient. Mean hospital stay for TPDAL was 1.33 +/- 0.71 SD days and for MST 1.8 +/- 0.83 SD days. Ninety-five percent (95%) confidence intervals for the difference in means demonstrated no difference between the two groups for length of operation, hospital stay, or number of doses of intravenous narcotics administered. CONCLUSIONS: The authors were unable to identify any benefit to thoracoscopic patent ductus arteriosus ligation versus muscle-sparing thoracotomy in terms of hospital stay, length of operation, or morbidity. Additionally, with MST there is a complete division of the PDA theoretically decreasing the risk of recurrence in comparison with clip ligation.

Case-Control Studies↗

Medical management of small preterm infants with symptomatic patent ductus arteriosus.

During 1975, 38 of 44 infants with a birth weight of less than or equal to 1,500 gm who developed pulmonary edema and congestive heart failure due to a patent ductus arteriosus were managed medically until the ductus closed spontaneously days or weeks later. Overall survival was 71%, and there were no deaths among 11 infants weighing more than 1,250 gm. Pulmonary complications were prevalent and were attributed to the extensive use of mechanical ventilation required to control pulmonary edema. The results of this study document the results to be expected when small preterm infants with a symptomatic patent ductus arteriosus are managed without surgical or pharmacologic intervention and provide a basis for the rational design of clinical trials evaluating other management approaches.

Blood Transfusion↗

Circulating prostaglandin E2 concentrations and patent ductus arteriosus in fetal and neonatal lambs.

We used pregnant sheep and their fetuses as well as newborn lambs (with and without severe respiratory distress due to prematurity) to study the differences in plasma clearance rate, production rate, and circulating concentrations of immunoreactive PGE2. Fetal PGE2 concentrations were significantly higher than simultaneous maternal concentrations. After delivery by cesarean section, all newborn animals were paralyzed and mechanically ventilated. The PGE2 concentrations fell in those lambs that required only minimal ventilatory support (FIO2 < 0.25) and were similar to maternal concentrations by two to three hours. Newborn lambs that developed severe respiratory distress (FIO2 < 0.55) continued to have concentrations that were even greater than fetal concentrations. The elevated PGE2 concentrations in severely distressed lambs were due not only to a decreased plasma clearance rate but also to an increased production rate of PGE2. Since PGE2 appears to maintain the patency of the ductus arteriosus in the fetus and preterm neonate, we examined the patency of the ductus arteriosus in 3-hour-old newborn lambs by radioactive microsphere injections. The ductus was more widely patent in lambs with higher concentrations of PGE2. The increased circulating concentrations of PGE2 in newborn lambs with severe respiratory distress may contribute to the pathogenesis of patent ductus arteriosus by exerting an additional vasodilatory effect on the vessel.

Animals↗

Increased shunt through the patent ductus arteriosus after surfactant replacement therapy.

Instillation of surfactant into the trachea of preterm infants with respiratory distress syndrome is associated with a 90% incidence of patent ductus arteriosus. We studied the effects of surfactant therapy on the ductus arteriosus in 12 preterm lambs. Flow across the ductus arteriosus and systemic blood flow were calculated from radioactive microsphere injections. All developed respiratory failure (pH less than 7.1, Paco2 greater than 60) by 30 minutes after birth. Between 30 and 60 minutes after birth, six lambs were treated with tracheal instillation of 50 mg/kg surfactant lipid. By two hours after birth, treated lambs differed significantly from controls in pH (7.27 +0.02 vs 6.97 +0.08) and Paco2 (43.3 +4.1 vs 85 + 15). There were no differences in Pao2 or PGE2 concentrations or ductus arteriosus resistance, but there was a significantly larger shunt through the ductus arteriosus in treated lambs. This increased shunt resulted from the significant drop in pulmonary vascular resistance and not from a change in patency of the ductus arteriosus. Surfactant replacement may require interventions directed specifically at the patent ductus arteriosus in sick preterm infants.

Animals↗