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At least 757 records · Page 42Linked to original sources
PubMed1985

Ligation of patent ductus arteriosus in very low birthweight premature neonates.

The results of ligation of a patent ductus arteriosus in 30 premature neonates with a very low birth weight were analysed. The mean gestational age at birth was 27 weeks and the mean weight 811 g. Attempted closure of the ductus with indomethacin in 19 infants failed, though there was temporary closure in nine. Congestive heart failure was present in 29 and respiratory distress in 22 patients. Endotracheal intubation with assisted ventilation was necessary in all cases. The mean age at operation was 13.5 days and ductal ligation was performed in the intensive care unit under local anaesthesia supplemented with pancuronium and pethidine. There were no intraoperative deaths, but five infants died in hospital. There were seven late deaths. Eighteen survivors have been followed for a mean of 26.5 months. Early ligation of a patent ductus arteriosus in premature infants with a very low birth weight improved the cardiorespiratory state. Long term follow up showed good clinical progress in two thirds of the surviving group.

Ductus Arteriosus, Patent↗
PubMed1988

Indomethacin and patent ductus arteriosus: effects on renal function in preterm lambs.

To examine the independent effects of a patent ductus arteriosus and of indomethacin therapy on the renal function of the preterm newborn, we created a preterm lamb model in which ductus diameter could be regulated. We studied 24 preterm newborn lambs. Eight lambs (group 1) had their ductus closed at delivery and received no indomethacin. Eight lambs (group 2) had their ductus closed and then received indomethacin (0.3 mg/kg) at 5.5 h; eight lambs (group 3) had their ductus kept open and then received indomethacin at 5.5 h. Hemodynamic and renal function measurements were made at 5 h (pretreatment) and at 12.5 h. In group 2 lambs there was a significant reduction in inulin clearance (GFR) and osmolal clearance after indomethacin. In contrast, lambs with an open ductus (group 3), when compared with lambs with a closed ductus (groups 1 and 2) at 5 h, already had significantly decreased blood pressure, GFR, urine volume, and osmolal clearance. Following indomethacin treatment, group 3 lambs showed no further decrease in renal function. We suggest that in preterm lambs with patent ductus, the apparent lack of renal dysfunction following indomethacin treatment reflects underlying diminished renal function.

Animals↗
PubMed2005

Patenting and licensing of university-based genetic inventions--a view from experience at Stanford University's Office of Technology Licensing.

University technology transfer offices license inventions created at universities to companies looking for tools, additions to their product pipelines, improvements or start-up opportunities. This paper will cover the motivations for conducting university technology transfer, an overview of Stanford's Office of Technology Licensing and its patenting and licensing practices, models of royalty sharing at university technology transfer offices, and patenting and licensing genetic information inventions at Stanford University. The terms 'invention' and 'technology' are used interchangeably throughout the paper.

California↗
PubMed1989

Pulsed Doppler measurement of left ventricular output as early predictor of symptomatic patent ductus arteriosus in very preterm infants.

High left ventricular output (LVO) values are associated with symptomatic left-to-right ductal shunting in preterm infants. However, LVO data prior to the occurrence of symptomatic patent ductus arteriosus (SPDA) are lacking. To determine whether serial measurements could predict a SPDA, we measured LVO from day 1 until day 10 with pulsed Doppler echocardiography in 25 preterm infants with birth weights of less than 1,250 g and hematocrits of more than 0.40. Eleven infants never developed patent ductus arteriosus symptoms and had LVO values within the normal range (190-310 ml/min/kg) with only minimal daily variations. The remaining 14 infants developed SPDA which required treatment with indomethacin, ductal ligation, or fluid restriction on days 2-5. From day 1 until day 5 their mean LVO values were significantly higher compared to the group without left-to-right ductal shunt and this increase was secondary to higher stroke volume values. An increase in LVO of more than 60 ml/min/kg consistently preceded SPDA by at least 24 h. Serial measurements of LVO using a single-pulsed Doppler approach can be used for early prediction of SPDA.

Birth Weight↗
PubMed1992

Long-term variability of heart rate increases with successful closure of patent ductus arteriosus in preterm infants.

Long-term variability (LTV) of heart rate was calculated continuously by a microprocessor in 25 preterm infants undergoing indomethacin treatment for closure of patent ductus arteriosus (PDA), in 24 preterm infants without signs of PDA, and in 10 neonates treated with prostaglandin E1 for cyanotic heart malformation. In infants with patent ductus arteriosus, LTV was lower than in controls. Following indomethacin, LTV increased most markedly (from 1.5 to 3.2; p less than 0.01) in infants with improved ventilation. The increase was less marked (from 1.8 to 2.5; p less than 0.05) in infants whose degree of respiratory failure did not change. LTV remained largely unchanged in infants who deteriorated. In 9 out of the 10 neonates treated with prostaglandin E1, LTV increased. We conclude that LTV corresponds to brain stem oxygenation and may be a useful tool to monitor treatment of PDA.

Alprostadil↗
PubMed1975

Hypertensive pulmonary vascular disease associated with patent ductus arteriosus. Primary or secondary?

In an infant with patent ductus arteriosus and pulmonary hypertension, elevated pulmonary vascular resistance persisted following ligation of the ductus. Histologic examination of a pulmonary biopsy at two years of age and tissue obtained at autopsy at three years of age showed obstructive pulmonary vascular disease. The question as to whether the organic vascular lesions are secondary to the effects of the patent ductus or part of pulmonary hypertension cannot be resolved. The age of the patient favors a primary etiology.

Age Factors↗
PubMed1979

Noninvasive detection of pulmonary hypertension in patent ductus arteriosus by pulsed Doppler echocardiography.

Twenty-five patients with proven patent ductus arteriosus were examined by pulsed Doppler echocardiography (PDE) before invasive assessment. Ten patients had normal pulmonary artery pressures, and by PDE, pandiastolic ductal flow. Fifteen patients had elevation of mean pulmonary artery pressure, and by PDE, all had abbreviations of diastolic ductal flow. PDE correctly distinguished between patients with normal pressure and those with evidence of pulmonary hypertension; the ECG did not allow such differentiation. Detection by PDE of pulmonary hypertension complicating patent ductus arteriosus appears to be clinically useful.

Blood Pressure↗
PubMed1991

Transcatheter occlusion of the persistently patent ductus arteriosus. Forty-month follow-up and prevalence of residual shunting.

BACKGROUND: Percutaneous closure of the persistently patent ductus arteriosus with the Rashkind prosthesis is an established effective therapeutic modality, although some patients are left with residual shunting. To evaluate this, a retrospective study of the prevalence of persistent shunting over a 40-month period in the first 190 patients was undertaken. METHODS AND RESULTS: All patients (male 45, female 145; mean age, 3.9 +/- 3.6 years; range, 5 months to 20 years) had serial clinical and color-flow echocardiographic follow-up at 6-12-month intervals (range, 6-40 months). Four patients required surgical removal of an embolized device, leaving a cohort of 186 patients in whom 196 procedures were performed, resulting in successful placement of 195 devices (43 17-mm [22%] and 152 12-mm [78%]). Complications occurred in seven of 195 procedures (3.6%). Nine of 10 attempted reocclusions (all with 12-mm devices) were successful. The prevalence of residual shunting was 38% at 1 year, 18% at 2 years, and 8% at 40 months. Patients with ductus measuring less than 4 mm had a higher success of initial occlusion. Thirty-four patients were left with residual shunting determined by color-flow Doppler study, but no anatomic or echocardiographic features were found predictive for residual shunting. All remain asymptomatic with 26 (76%) having no detectable murmur, two (6%) a continuous murmur, and six (18%) a systolic murmur. CONCLUSIONS: Catheter occlusion will obviate the need for surgery in the majority of patients presenting with persistently patent ductus arteriosus. Reocclusion has been found feasible in those with continuous murmurs (nine of nine) and should be offered early because it is unlikely for spontaneous closure to occur in this group. It appears prudent to follow those with small residual shunting because further spontaneous closure can occur.

Adolescent↗
PubMed1996

Computed tomography and magnetic resonance findings in long-standing patent ductus. Case reports.

Two adult patients with patent ductus arteriosus (PDA), resulting in Eisenmenger's syndrome, were evaluated by computed tomography and Magnetic Resonance imaging of the chest, which clearly demonstrated the patent arterial duct as well as the morphologic features of long-standing pulmonary arterial hypertension. Massively dilatated, calcified pulmonary arteries were seen, and the arterial duct was identified as a vascular channel between the distal aortic arch and the main pulmonary artery.

Ductus Arteriosus, Patent↗
PubMed1985

The contractility and performance of the preterm left ventricle before and after early patent ductus arteriosus occlusion in surfactant-treated lambs.

The influence of left-right ductal shunting on early hemodynamic responses, namely left ventricular performance, contractility, and systemic perfusion was evaluated in nine preterm lambs (120 days gestational age) treated with surfactant. Blood gases were maintained in the physiological range using mechanical ventilation; hemodynamic and blood flow measurements (radionuclide labeled microspheres) were obtained before and after occlusion of the patent ductus arteriosus with a catheter balloon. The mean left-right ductal shunt before occlusion (1.2 h postnatal age) was 59 +/- 11% SD. Left ventricular output was increased in all lambs with PDA (pre: 306 +/- 106 versus post: 155 +/- 31 ml/min/kg; p less than 0.001); effective systemic blood flow and organ blood flows did not change. The left ventricle end-diastolic volume was increased in all and decreased following ductal occlusion (pre: 2.0 +/- 0.4 versus post: 1.5 +/- 0.2 ml/kg; p less than 0.01). Cardiac rate, ejection fraction, and contractility (peak dP/dt) did not change. Right-left ductal shunting was not detected in six similarly treated lambs. Thus, during the 1st h of life the hemodynamic profile of preterm lambs with patent ductus arteriosus was characterized by large magnitude left-right shunt and a "high" cardiac output state sufficient to maintain unchanged systemic perfusion. The increased left ventricle output was accomplished by increasing end-diastolic volume (Frank-Starling mechanism), but left ventricle contractility remained unchanged. We speculate that the preterm left ventricle may be unable to sustain the high level of pump performance and contractility required to compensate for the ductal "steal" of systemic blood flow.

Animals↗
PubMed1987

Atrial natriuretic peptide in patent ductus arteriosus.

Plasma concentrations of atrial natriuretic peptide (ANP) were measured in nine infants (age 4 days-9 months) before and after closure of patent ductus arteriosus. Initially all patients had marked distention of the left atrium as indicated by a left atrium to aortic root ratio greater than or equal to 1.3 on echocardiography. After closure of the ductus, operative in six and pharmacological in three patients, left atrial size normalized (left atrium to aortic root ratio less than 1.3) in all patients, except in one treated surgically. Before closure the plasma concentration of ANP was 86-2224 pg/ml and after closure 44-1400 pg/ml. There was a significant correlation between the size of left atrium and plasma concentration of ANP (r = 0.56; p = 0.01). Our results suggest that in infants with patent ductus arteriosus the left atrium is the main source of ANP. The secretory rate of ANP decreases immediately after restoring left atrial size by closure of the ductus.

Atrial Natriuretic Factor↗
PubMed1989

Effect of patent ductus arteriosus on water accumulation and protein permeability in the lungs of mechanically ventilated premature lambs.

To examine the effect of a patent ductus arteriosus on water accumulation and protein permeability in the premature, ventilated lung, we studied 16 lambs at 121-127 d gestation (term = 145 d). Water accumulation was assessed by the wet:dry wt ratio of the blood-free left lung. Protein permeability was assessed by the albumin content and by the recovery of 125I-albumin in the right lung lavage fluid 1 h after intravenous injection. Using a model that allows mechanical control of ductus patency, we compared nine lambs with patent ductus (left-to-right shunts 42 +/- 18% to left ventricular output) with seven lambs with closed ductus. The animals were studied over 3 h. In the open ductus lambs, 0.85 +/- 0.36 and 1.76 +/- 1.87%/h of the injected 125I-albumin was recovered in the lavage fluid and lung tissue, respectively. In the closed ductus lambs, the corresponding amounts were 0.71 +/- 0.21 and 0.71 +/- 0.22%/h; these differences were not statistically significant. Similarly, blood-free wet:dry ratios did not differ significantly between the two groups (7.01 +/- 1.28 open ductus versus 6.55 +/- 0.82 closed ductus). We concluded that patency of the ductus arteriosus does not significantly affect water accumulation and net protein transudation into the airways of preterm lambs in the first hours of life. Therefore, some other feature of immaturity must be responsible for the large protein leaks previously observed by others.

Albumins↗
PubMed1991

Patent ductus arteriosus increases lung fluid filtration in preterm lambs.

Previous studies showed that increased pulmonary blood flow from a patent ductus arteriosus had little or no effect on the amount of fluid in the lungs of mechanically ventilated preterm lambs. The purpose of this study was to examine the effect of a patent ductus arteriosus on lung vascular permeability and to see whether increased pulmonary lymph flow might compensate for the increased rate of fluid filtration. Using a model that allows mechanical control of ductus patency, we studied the effects of increased pulmonary blood flow on lung vascular pressures in six mechanically ventilated premature lambs at 136 +/- 2 d gestation (mean +/- SD) (term = 145 d). We measured lung lymph flow and protein concentrations in lymph and plasma to assess pulmonary vascular fluid filtration and protein permeability. We studied each lamb during sequential steady state periods, first with the ductus open and then with it closed. When the ductus was open, pulmonary blood flow was twice what it was when the ductus was closed. Mean pulmonary artery pressure and left ventricular end-diastolic pressure were greater with the ductus open [40 +/- 5 torr (5.3 +/- 0.7 kPa) and 8 +/- 3 torr (1.1 +/- 0.4 kPa), respectively] than when it was closed [24 +/- 3 torr (3.2 +/- 0.4 kPa) and 4 +/- 2 torr (0.5 +/- 0.3 kPa), respectively]. When the ductus was open, lymph flow was 68% greater and lymph protein concentration was 17% lower than when the ductus was closed. Lymph protein clearance (lymph flow x lymph protein concentration/plasma protein concentration) was 39% greater when the ductus was open.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

Intravenous indomethacin therapy in infants with a patent ductus arteriosus complicating other congenital heart defects.

In the present study, 0.2-0.6 mg/kg (0.4+/-0.2, mean +/- standard deviation) indomethacin was administered intravenously to close a patent ductus arteriosus in 13 infants with co-existing congenital heart defects whose ages ranged from 3 to 48 (14+/-14) days. All of them were hemodynamically ductus-independent and symptomatic. Echocardiography demonstrated that the ductus had closed in 8 infants, aged 3-33 (12+/-10) days (responders), but had not closed in 5 infants aged 6-48 (19 +/-19) days (non-responders). There was no significant difference between the responders and non-responders in their age, body weight, minimal diameter of the duct, dose of indomethacin, gestational age, birthweight, or Apgar score. One possible major complication might be associated with indomethacin. However, intravenous indomethacin should be considered prior to surgical ligation as one option for infants with a symptomatic patent ductus arteriosus complicated by other congenital heart defects.

Cardiovascular Agents↗
PubMed1976

Total anomalous pulmonary venous return with associated patent ductus arteriosus. Two cases with successful correction.

A large patent ductus arteriosus associated with total anomalous pulmonary venous return results in a unique hemodynamic pattern, and long-term survival has been rare. Two patients, aged five and 18 years, underwent successful surgical repair of supracardiac total anomalous pulmonary venous return and an associated large patent ductus arteriosus. The association of the Noonan syndrome in the 18-year-old woman is of additional interest.

Adolescent↗
PubMed1977

Membranous subaortic stenosis and patent ductus arteriosus.

Six children (five of them girls) each initially had a large patent ductus arteriosus with auscultatory, radiologic, and electrocardiographic findings typical of that lesion. After surgery for the lesion, an ejection-type basal systolic murmur led to detection of discrete membranous subaortic stenosis, which became worse in late childhood. The murmur became louder, the systolic pressure gradient increased from slight to significant, and hypertrophic subaortic stenosis or aortic insufficiency (or both) developed in the older children. Surgical excision of the membrane afforded improvement, except in one patient with the most severe involvement. Because of the unexpected finding of discrete membranous subaortic stenosis in these infants and young children who had undergone surgery for a large patent ductus arteriosus and because of the treacherous worsening of the effects of the discrete membranous subaortic stenosis as childhood progressed, it is important that those patients with a persistent systolic murmur after ductal ligation not be discharged from cardiac follow-up as cured. Serial cardiac catheterization during the growing years appears to be the most accurate way of detecting worsening discrete membranous subaortic stenosis, so that the membrane can be excised before severe complications occur.

Angiocardiography↗
PubMed1983

Repair of aortopulmonary window at left thoracotomy for patent ductus arteriosus.

The inability to differentiate accurately between patent ductus arteriosus and aortopulmonary window may occasionally result in finding an aortopulmonary window while prepared to close a patent ductus arteriosus at left thoracotomy. Anatomic and technical factors now allow aortopulmonary window closure from the left chest using surgical clips in certain selected cases. The successful repair of such a case is presented.

Aorta↗
PubMed1987

Isolated right-sided patent ductus arteriosus in right-sided aortic arch. Report of two cases.

An isolated right-sided patent ductus arteriosus has not been reported previously to occur in right-sided aortic arch associated with an aberrant left subclavian artery. We report such anomalies in two adult patients. In the first case of a 19-year-old woman, the ductus was successfully ligated via a left posterolateral thoracotomy; however, many technical difficulties were encountered. In the second case of a 36-year old woman, a right posterolateral thoracotomy enabled detailed demonstration of the ductus and its surrounding structures and facilitated its successful ligation. An isolated right-sided patent ductus arteriosus should be approached via right thoracotomy.

Adult↗