Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PATENTS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80Linked to original sources
PubMed1989

A new device for transcatheter closure of the patent ductus arteriosus. A feasibility study in dogs.

A new device for transcatheter closure of the patent ductus arteriosus was developed and initially evaluated in the vasculature of adult mongrel dogs. The device consists of a nylon sack that can be made in various sizes and shapes. A small flexible crossbar attached to the distal end maintains the position of the sack while it is filled with a segment of modified guide wire. The device is delivered coaxially through a 10-Fr Teflon catheter and is easily repositioned or retrieved before release. The expansile force of the sack against the vessel wall can be varied, and its stability is easily checked prior to detachment. The device produced immediate and permanent vascular occlusion without inflammation or erosion. Over time, the entire unit became incorporated into the vessel wall by neointimal encasement. Nylon sacks offer a simple, unique method of closing virtually any ductus arteriosus without general anesthesia and major surgery.

Animals↗
PubMed1999

Transvenous closure of patent ductus arteriosus with Ivalon plugs. Multicenter experience with a new technique.

RATIONALE AND OBJECTIVE: The authors assess the clinical efficacy of transvenous closure of patent ductus arteriosus (PDA) with a new plug consisting of Ivalon foam and a platinum/iridium frame with four aortic and two pulmonary nitinol struts. The most widely used devices for transcatheter treatment of PDA (Porstmann plug, Rashkind umbrella, Botallo occluder, coils) have specific limitations inherent to their design (e.g., transarterial approach, residual shunts, limited retrieval). METHODS: Between 1994 and 1997, PDA closure was attempted in 33 children and 67 adolescents and adults in 7 clinical centers; PDA diameter was 2 to 11 mm. Plug diameter was 6 to 20 mm, and 8 to 16 F venous sheaths were used for insertion. RESULTS: Placement was successful in 98% (with a single plug in 88%, and a second or third plug in 10%) and unsuccessful in 2%. Plugs were retrieved after malpositioning in 12 of 12 patients and after pulmonary embolization in 2 of 3 patients. One patient underwent surgery for removal of an embolized plug. Complete PDA closure was proved by aortography and color Doppler echocardiography in 85% (40 of 43 patients with a PDA 2-3.9 mm, 30 of 36 patients with a PDA 4-5.9 mm, and 15 of 21 patients with a PDA 6-11 mm). During a median follow-up interval of 16 months, there were no complications (infection, hemolysis, fracture, embolization). CONCLUSION: The new plug device can be used successfully in patients with a PDA diameter up to 11 mm. Further investigations are underway to determine the definite clinical value of this technique.

Adolescent↗
PubMedDate not supplied

Airway obstruction by right aortic arch with right-sided patent ductus arteriosus: demonstration by MRI.

An unusual cause of airway obstruction was demonstrated by MRI in two infants with congenital heart disease. The two infants experienced airway obstruction caused by a right aortic arch with right-sided patent ductus arteriosus. The diagnosis was established by MRI prior to surgery; angiography did not demonstrate the critical relationship between the large ductus and the airway. Axial, sagittal, and coronal MRI displayed the right arch, dilated ductus, and the compression of the proximal right bronchus and distal trachea by the ductus. Surgical findings confirmed the MR diagnosis. Thus, MRI can be used to localize the site of airway obstruction and to demonstrate unusual types of vascular anomalies.

Airway Obstruction↗
PubMedDate not supplied

Localized intestinal perforation following intravenous indomethacin for patent ductus arteriosus.

We describe a very low birth weight infant given intravenous indomethacin for a symptomatic patent ductus arteriosus who subsequently developed a gastrointestinal perforation. Although this is a well-known complication of enteral preparations, it has not been described with the intravenous form. Various mechanisms described in the literature by which the intravenous route of administration may compromise the bowel are presented. Although rare, gastrointestinal complications with intravenous indomethacin may become more prevalent with its increased use.

Ductus Arteriosus, Patent↗
PubMed1980

Severe pulmonary hypertension with patent ductus arteriosus.

A 36-year-old man was found to have severe pulmonary hypertension and a right-to-left shunt secondary to a patent ductus arteriosus. Attempt at surgical closure was unsuccessful. The patient was followed up for 21 years, and his only significant medical problem is leg weakness to moderate exertion.

Ductus Arteriosus, Patent↗
PubMed1981

Ligation of patent ductus arteriosus in premature neonates: anesthetic management.

A retrospective study covering a five-year period was conducted on 40 premature neonates who had had general anesthesia for surgical correction of patent ductus arteriosus. The anesthetic management of these patients was carefully reviewed. The mean weight at surgery was 1,243 gm, and the mean gestational age at birth was 29.5 weeks. Various technics of anesthesia were used, the most common being the use of nitrous oxide, oxygen, relaxant, and narcotics. There were no intraoperative deaths. Two patients had massive blood loss intraoperatively. There were 12 postoperative deaths in the series, and 12 patients had serious long-term disability, many were combinations of hearing, visual, and psychomotor disturbances. Advances in neonatology, surgery, and anesthesiology have improved the outlook of these seriously ill patients.

Anesthesia, General↗
PubMed2004

Patent ductus arteriosus as a natural cause of pulmonary hemorrhage in infants: a medicolegal dilemma.

Patent ductus arteriosus (PDA) is a recognized risk factor for massive pulmonary hemorrhage (MPH) in the newborn and is generally seen in association with other MPH risk factors such as prematurity. We report 6 cases of sudden and unexpected death of infants older than 4 days with MPH and PDA at autopsy. The cases were reviewed for other factors that could contribute to MPH to ascertain whether PDA is directly linked to MPH. Histology samples were examined for distribution of hemorrhage in the lungs and iron stained for hemosiderin evaluation. All of the cases had clinical histories and scene examinations which raised the differential diagnosis of mechanical asphyxia in the form of so-called overlayings. The diagnostic dilemma of attributing the MPH to the PDA as the sole cause, dual cause, or incidental finding is discussed. These cases illustrate the medicolegal dilemma faced by the pathologist, as well as the need for further research into the potential association of PDA with MPH.

Asphyxia↗
PubMed2004

Intravenous indometacin in preterm infants with symptomatic patent ductus arteriosus. A population pharmacokinetic study.

AIMS: To characterize the population pharmacokinetics of indometacin in preterm infants with symptomatic patent ductus arteriosus and to investigate the influence of various factors on the response to treatment. METHODS: Data were collected from 35 infants (gestational age 25-34 weeks; postnatal age 1-77 days) in neonatal units in Belfast and Copenhagen. Infants received an initial course of up to three doses of intravenous indometacin (0.1-0.2 mg kg(-1)) as considered appropriate by the treating physician. For those infants who did not respond to therapy or in whom the ductus reopened, a second course was sometimes given. Population analysis of the 185 plasma concentrations obtained was conducted using NONMEM and pharmacokinetic and demographic differences between responders and nonresponders were compared. RESULTS: The concentration-time course of indometacin was best described by a one-compartment model. The final population parameter estimates of clearance (CL) and volume of distribution (V) (standardized to the median weight of 1.17 kg) were 0.00711 l h(-1) and 0.266 l, respectively. CL increased from birth by approximately 3.38% per day and V by approximately 1.47% per day. Concomitant digoxin therapy resulted in a 30% decrease in V. Interindividual variability in CL and V was 41% and 21%, respectively. Interoccasion variability for CL was 43%. Residual variability corresponded to a standard deviation of 0.148 mg l(-1). Closure occurred in 75% of infants with a plasma concentration > or = 0.4 mg l(-1) 24 h after the last dose. CONCLUSIONS: Dosing regimens for indometacin should take into account the weight and postnatal age of the infant and any concomitant digoxin therapy. The population estimates can be used to determine typical values of CL and V allowing the prediction of individualized doses of indometacin that should increase the probability of achieving a 24 h plasma concentration > or = 0.4 mg l(-1). Although the pharmacokinetic estimates will be affected by both interindividual and within-individual variation, it is anticipated that this approach will decrease the variability of exposure and optimize treatment outcome.

Cardiovascular Agents↗
PubMed2005

Dose-finding study of ibuprofen in patent ductus arteriosus using the continual reassessment method.

OBJECTIVE: Intravenous ibuprofen (IBU) has been found to be as effective as indomethacin for the treatment of patent ductus arteriosus (PDA) in preterm infants and has been associated with fewer adverse effects in comparative phase III studies. The dose regimen used (10-5-5 mg/kg/day) was based on limited pharmacokinetic data and no phase II study was available to determine the optimal dose of IBU for this indication. The present study was designed to determine the minimum effective dose regimen (MEDR) of IBU (one course) required to close ductus arteriosus in preterm infants. METHOD: A double-blind dose-finding study was conducted using the continual reassessment method, a Bayesian sequential design. Two distinct target closure rates were initially chosen according to postmenstrual age (PMA) at birth: 80% in infants with a PMA of 27-29 weeks, and 50% in infants with a PMA < 27 weeks. Forty neonates (20 in each PMA group) with PDA were treated between days 3 and 5 of life. Four different dose regimens were tested: loading doses of 5, 10, 15 or 20 mg/kg, followed by two doses (1/2 loading dose) at 24-h intervals. Efficacy was evaluated by echocardiography 24 h after the third infusion. RESULTS: In infants with a PMA of 27-29 weeks, the estimated MEDR was 10-5-5 mg/kg with a final estimated probability of success of 77% (95% credibility interval: 56-92%). The 15-7.5-7.5 mg/kg dose regimen had a better estimated probability of success (88%, 95% credibility interval: 68-97%), but resulted in more minor renal adverse effects. In contrast, in infants with a PMA < 27 weeks, the estimated MEDR was 20-10-10 mg/kg with an estimated probability of success of 54.8% (95% credibility interval: 22-84%), whereas the conventional dose regimen resulted in a low estimated probability of success (30.6%, 95% credibility interval: 13-56%). In these infants, compared with those with a PMA of 27-29 weeks, minor renal adverse effects were more frequent from the 10-5-5 mg/kg/day dose regimen and did not appear to be clearly dose related. CONCLUSION: This study confirms that the currently recommended dose regimen (10-5-5 mg/kg) of IBU is associated with a high closure rate (80%) and few adverse effects in premature infants with a PMA of 27-29 weeks. The failure rate was much higher below 27 weeks. A higher dose regimen (20-10-10 mg/kg) might achieve a higher closure rate. However, tolerability and safety of this dose regimen should be assessed in a larger population before considering the use of these doses for ductus arteriosus closure.

Bayes Theorem↗
PubMed1988

Patent ductus arteriosus in a cohort of 1338 preterm infants: a collaborative study.

As part of a prospective national survey on morbidity and mortality of all infants born at less than 32 weeks and/or weighing less than 1500 g in the Netherlands we studied the incidence of symptomatic patent ductus arteriosus (PDA) in infants surviving at least 24 hours. In 1252 of the 1338 infants the presence or absence of PDA could be established. The incidence of PDA was 10.7%. Logistic regression analyses revealed that idiopathic respiratory distress syndrome (IRDS) was the most predictive factor, followed in order of importance by septicaemia, birthweight, prolonged rupture of membranes and gestational age. None of the other maternal and perinatal factors showed any association with the occurrence of PDA. Furthermore, bronchopulmonary dysplasia (BPD) and necrotising enterocolitis (NEC) were found to be sequelae of PDA. The combination of IRDS, very pre-term birth and septicaemia should be considered as high risk for the development of PDA.

Ductus Arteriosus, Patent↗
PubMed1987

Periventricular haemorrhage: association with patent ductus arteriosus and its treatment with indomethacin or surgery.

A prospective study on 150 infants with a birthweight of 1250 g or less was carried out to investigate the effects of patent ductus arteriosus (PDA), haemorrhagic pulmonary oedema (HPO), Indomethacin therapy and surgical ligation on the development of periventricular haemorrhage (PVH) or the extension of pre-existing PVH. The incidence of PVH, diagnosed by serial cerebral ultrasonography was 44% and the incidence of PDA, diagnosed by serial M-mode and contrast echocardiography, was 45%. During the first 8 days after birth when the infants were vulnerable to PVH, the development of PDA did not lead to the development or extension of PVH in 85% of infants. Haemorrhagic pulmonary oedema also had no effect on PVH in 71% of infants. Compared with infants whose PDA or HPO had no effect on PVH, those who had development or extension of haemorrhage had significantly more severe hypercapnia, blood gas instability and hypotension associated with the occurrence of PDA or HPO. Early Indomethacin therapy was not associated with the development or extension of PVH in 93% of infants. Although an elevation of arterial blood pressure was demonstrated after ductal ligation, surgery was performed after 1 week of age in all infants and in no instance was there an effect on PVH. This study suggests that PDA leads to PVH only if it causes significant blood gas and blood pressure disturbances which are known to affect cerebral blood flow adversely.

Cerebral Hemorrhage↗
PubMed1991

Intravenous indomethacin therapy in preterm neonates with patent ductus arteriosus.

This study examined the response of the patent ductus arteriosus (PDA) to intravenous Indomethacin using serial two dimensional and Doppler echocardiography and documented the complications associated with therapy. Thirty-six preterm neonates who were oxygen and ventilator dependent were studied when they were aged 3-7 days. The PDA initially closed in 22 (61%) and constricted in seven (19%) of the infants. It was non-responsive in five (14%) and the treatment was stopped because of complications in two (6%). Only three (43%) of seven neonates given a second course had PDA closure. In the 25 instances where there was PDA closure following Indomethacin, re-opening was documented echocardiographically on three (12%) occasions. Overall, Indomethacin therapy was successful in 29 (81%) neonates, PDA ligation was required in four (11%) and three died from unrelated causes. Three (8%) neonates developed major complications: multiple gastric perforations in the first, focal ileal perforation in the second, and necrotizing enterocolitis in the third. Treatment failure, PDA ligation and major complications occurred exclusively in neonates less than 28 weeks gestation. In view of the relatively low efficacy and high major complication rate in these extremely preterm infants, a randomized clinical trial needs to be conducted using two dimensional and Doppler echocardiography to allow accurate assessment of the PDA response to intravenous Indomethacin.

Ductus Arteriosus, Patent↗
PubMed1994

A blinded comparison of clinical and echocardiographic evaluation of the preterm infant for patent ductus arteriosus.

The accuracy of the characteristic physical signs of a patent ductus arteriosus (PDA), that is, a systolic murmur, increased volume of pulses and increased praecordial activity, in diagnosing a haemodynamically significant PDA in ventilated premature infants was prospectively evaluated. Fifty-five ventilated preterm infants (birthweight < 1500 g) had daily echocardiographic and clinical evaluation for a PDA for the first 7 days of life. The examiners were blinded to each other's findings. Probability analysis was performed for the accuracy of each clinical sign in detecting a haemodynamically significant PDA as defined by echocardiographic criteria. Clinical signs were poor at detecting a significant PDA in the first 4 days of life. On day 1, none of the 10 infants with a significant PDA had a murmur. By day 4, clinical signs were better at detecting a significant PDA, but specificity remained poor with many false positive signs. Six infants had murmurs with a closed duct. The development of echocardiographic haemodynamic significance preceded the development of physical signs by a mean of 1.8 days. Significant ductal shunts often occurred silently, but the development of a murmur often marked an increase in the velocity of the flow through the duct rather than an increase in the size of a shunt. This study confirms that echocardiography is required for the reliable early diagnosis of a PDA in ventilated preterm infants.

Ductus Arteriosus, Patent↗
PubMed1997

Prolonged low-dose indomethacin therapy for patent ductus arteriosus in very low birthweight infants.

OBJECTIVE: To determine the efficacy and side-effects of prolonged low-dose indomethacin therapy in very low birthweight (VLBW; < 1500 g) infants with a haemodynamically significant patent ductus arteriosus (hsPDA). METHODOLOGY: Very low birthweight infants admitted over a 16 month period were studied (8 months, retrospectively and 10 months, prospectively). Cross-sectional and M-Mode echocardiograms with pulsed-wave and colour Doppler were performed to assess the significance of ductal patency. RESULTS: Forty-one (28%) of 148 VLBW infants were diagnosed to have hsPDA. Indomethacin therapy was successful in 90% after the first course, increasing to 95% after the second course. The recurrence rate after the first course was 3%. Minor and transient complications included oliguria, urea retention, hyponatraemia and thrombocytopenia. Although three infants had focal bowel perforation and the fourth had bowel perforation associated with necrotizing enterocolitis, the incidence of gastrointenstinal pathology was not significantly different from infants without hsPDA and not given indomethacin. CONCLUSIONS: Very low birthweight infants with hsPDA have a high response rate and low recurrence rate to prolonged low-dose indomethacin therapy. Side-effects were mild and transient. However, it is prudent to be cautious when administering indomethacin in critically ill infants < 1000 g with hsPDA who manifest clinical features of bowel ischaemia.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

Two-dimensional pulsed Doppler echocardiographic technique for estimating pulmonary to systemic blood flow ratio in children with atrial septal defect and patent ductus arteriosus.

A two-dimensional pulsed Doppler echocardiographic method was evaluated for quantifying the pulmonary (Qp) to systemic (Qs) blood flow ratio. Twenty six patients were studied, 15 with atrial septal defect (ASD) and 11 with patent ductus arteriosus (PDA). An apical four-chamber view was used to measure the maximal Doppler flow velocities in the right and left ventricular inflow regions (RVIR and LVIR) and the maximal diameters of the tricuspid and mitral anuli at diastole. The two-dimensional pulsed Doppler pulmonary to systemic blood flow ratio (Qp/Qs) estimation involved calculating the area of the Doppler flow velocity signal along the time scale multiplied by the diameter of either the tricuspid or mitral anulus as measured on the apical four-chamber view. In ASD patients, Qp was measured at RVIR and Qs at LVIR. In PDA patients, Qp was calculated at LVIR and Qs at RVIR. Twenty-six healthy children comprised the control group. The areas of the Doppler flow velocity signals along the time scales of RVIR and LVIR were also quantified and the diameters of the tricuspid and mitral anuli were measured. In the control group, the linear correlation of the trans-mitral M(d)*M(a) to trans-tricuspid T(d)*T(a) value was r = 0.909, n = 26. The correlations between Doppler Qp/Qs ratio estimates and those obtained at cardiac catheterization were r = 0.902, n = 15 in ASD and r = 0.967, n = 11 in PDA. These results suggest a clinical application of this Doppler echocardiographic method in the noninvasive estimation of the cardiac shunt in ASD and PDA.

Blood Flow Velocity↗
PubMed1994

Pharmacokinetics of mefenamic acid in preterm infants with patent ductus arteriosus.

The pharmacokinetics of mefenamic acid (MA), 2 mg/kg, were studied in 17 preterm infants with symptomatic patent ductus arteriosus. They were given this dosage orally at 24 h intervals. There were marked inter-individual differences in some of the pharmacokinetic parameters after the first dose; peak plasma concentration (Cmax) varied from 1.2 to 6.1 micrograms/mL with a mean of 3.8 micrograms/mL, time to reach Cmax (tmax) varied from 2 to 18 h with a mean of 7.7 h and plasma half-life (t1/2) varied from 3.8 to 43.6 h with a mean of 18.7 h. The group of infants (10/17) who had ductus closure after the first dose had significantly lower clearance (P < 0.01), longer t1/2 (P < 0.01) and higher 24 h plasma concentration (P < 0.001) compared to the group of infants (7/17) who had no ductus closure after the first dose. It appeared that the plasma concentration of MA had to be above 2.0 micrograms/mL and maintained at this concentration for at least 12 h for MA associated with ductus closure in preterm infants to take effect. In view of the inter-individual variation of plasma MA concentration and the effective plasma concentration, we suggest that measurement of the plasma concentration should be done 24 h after the first dose. This might be useful for safe and effective therapy for infants with ductus closure failure after the first dose.

Administration, Oral↗
PubMed2006

Surgical closure of patent ductus arteriosus reduces the cerebral tissue oxygenation index in preterm infants: a near-infrared spectroscopy and Doppler study.

BACKGROUND: The aim of this study was to investigate the effects of patent ductus arteriosus (PDA) ligature on cerebral oxygen saturation, cerebral blood volume (CBV) and cerebral blood flow velocity by means of near-infrared spectroscopy (NIRS) and transcranial Doppler simultaneous examinations. METHODS: This is an observational study considering 16 babies of gestational age 24-34 weeks diagnosed with PDA who underwent surgical ligation. The cerebral oxygen saturation, CBV and blood gases values were obtained 35 min before ligation, so also around the 14th and 27th min after the clip's insertion. RESULTS: Cerebral oxygen saturation, measured as tissue oxygenation index (TOI), decreased significantly after PDA ligation from a basal value of 61.1 (3.8) before surgery to 56.6 (3.3) and 55.8 (2.6)%, for the 14th and 27th min, respectively (P<0.04). CBV before and after clipping was unvaried. A negative correlation was found between DeltapH and DeltaCBV after ligation (R=0.52, P=0.03), whilst a positive correlation was found between DeltaCBV and DeltaP(aCO2) (R=0.62, P=0.009). pH increased at the 27th min post-ligation. CONCLUSIONS: NIRS is a tool for obtaining information on cerebral oxygen saturation and CBV changes during surgical PDA ligation at the bedside. A fall in TOI suggests an increased oxygen extraction during PDA surgery. The lack of increase in DeltaCBV or in diastolic flow velocity show that the PDA before the clipping did not limit cerebral blood flow, the drop in TOI suggests increased oxygen consumption over the clip and the need for accurate monitoring of oxygen utilization after the surgical treatment.

Blood Flow Velocity↗