Small PDA Research Articles

Rare association of obstructed supracardiac total anomalous pulmonary venous connection with coarctation of aorta: case report

Coexistence of TAPVC (total anomalous pulmonary venous connection) and coarctation of aorta rarely occurs. Newborn weighing 2.4 kg admitted in Sangli civil hospital NICU with respiratory distress with cyanosis. Chest X-ray of baby was suggestive of ground glass appearance of bilateral lung fields and cardiomegaly. SpO2 of baby was fluctuating between 85 to 90% on nasal CPAP. 2D echo showed baby was having obstructed supracardiac TAPVC with severe discrete post-ductal coarctation of aorta. There was stretched PFO shunting R-L and small PDA shunting R-L. Baby was planned for emergency surgery but couldn’t make it to operation theatre and succumbed within 30 hours of life. Till now there are very few case reports of TAPVC with coarctation but no case of obstructed supracardiac TAPVC with coarctation has been reported.

The Evaluation of Left Atrial to Aortic Root Diameter Ratio after PDA Closure in Children

Background: Ductus arteriosus (DA) is a vascular structure that makes a link between the proximal descending aorta and main pulmonary artery near the origin of the left pulmonary artery. The present study aimed to assess the changes of LA/Ao ratio after PDA closure in children.Methods: This cross-sectional study was performed on 635 children with PDA in the Ali Asghar clinic, Zahedan, Iran, from 2003 to 2019. The participants were followed for at least one year after discharge from the hospital after intervention. PDA diagnosis was conducted in accordance with the echocardiography performed by a pediatric cardiologist using Mylab 60 and challenged 7000 made in Italy. The analyses were performed by SPSS 20.00, considering 0.05 as the significant error.Results: As compared to the baseline measures before the interventions, the growth rates of LA/Ao ratio decreased by 24% and 10% in the first and second 6 months after the intervention. During the first 6 months after the intervention, the percentages of LA/Ao ratio reduction were 23%, 25% and 22% in small, medium and large PDA while these percentages were 7%, 13% and 16% during the second 6 months after the intervention, respectively. Regarding the intervention, the percentages were 25%, 24%, 24% and 24% in PDAs that were, respectively, closed by medication, surgery, occlusion device and VATS in the first six months after the intervention. The percentages were, respectively, 9%, 10%, 11% and 9% for the second 6 months after the intervention. The percentages were, respectively, 24%, 24% and 21% in those PDAs with residuals, no complication and PH in the first six months after the intervention. This pattern was, respectively, 8%, 9% and 16.6% for the second 6 months after the intervention.Conclusion: It was concluded that LA/AO ratio had the highest decrease during the first six months after the intervention, so that PDAs with moderate sizes or those who had medication as intervention or those with residual complications had the highest percentages of reduction.

Transcatheter closure of silent patent ductus arteriosus for prevention of endocarditis is justified

A diagnosis of ductal infective endocarditis (DIE) usually relies on the clinical histories of infectious syndrome, results of blood cultures and echocardiography. It remains a therapeutic challenge. The prognosis is still poor. Is the prevention of infective endarteritis a valid reason to always close the isolated silent PDA in childhood? The question is not yet eluded [1] , [2] , [3] , [4] . We present the case of six years old girl with DIE developed after dental procedure. The patient was managed by combined medical and early surgery with favorable evolution. A six year old girl was admitted to our service with tachypnea, fatigue and fever lasting for seven days. The patient had dental procedures few days earlier. The physical examination revealed a temperature at 40 °C and a left subclavian murmur. The acute phase marker levels were significantly elevated and β-hemolytic group A streptococcus was grown in his blood culture. Echocardiography revealed vegetations with the diameter of 10 mm on the left side of the PDA ( Fig. 1 ) with turbulent flow in the left pulmonary artery. Treatment with ceftriaxone 200 mg/kg/day and gentamycin 5 mg/kg/day was started then readapted according to antibiogram. The operation was performed on day 15 of antibiotherapy ( Fig. 2 a and b), whom was continued for 4 weeks. The fever did not return and the clinical course of the patient was stable; the final echocardiogram revealed the absence of left ventricular dilatation with a correct systolic function, normal pulmonary pressure. She was discharged four weeks after the surgical cardiac procedure. Infective endarteritis (IE) complicating PDA is very rare nowadays and the risk is very low especially in the industrialized world. Indeed, standardized management by a skilled multidisciplinary team with expertise in imaging, surgery and intensive care has proven to decrease mortality [3] , [4] , [5] , [6] , [7] . Primary prevention is vital. Even though it was not clear if the closure of a small PDA was beneficial, routine closure of any PDA in children and young adults appeared reasonable. The reasons for this recommendation included the risk of infective endocarditis and low-or-zero morbidity from closure, especially when using a transcatheter device [8] , [9] .

Effectiveness of Dual Medication Therapy (Oral Acetaminophen and Oral Ibuprofen) for the Management of Patent Ductus Arteriosus in Extremely Premature Infants: A Feasibility Trial.

The study aimed to evaluate the efficacy of dual medication therapy (DMT) with oral acetaminophen and oral ibuprofen for the closure of a hemodynamically significant patent ductus arteriosus (hsPDA). In a prospective case-control cohort study (July 2017-May 2019), infants <29 weeks' gestational age and birth weight <1,000 g at ≤14 postnatal days with hsPDA and ratio of the smallest ductal diameter to the ostium of the left pulmonary artery diameter >0.5 were eligible. Infants received 10 mg/kg oral ibuprofen followed by two additional doses of 5 mg/kg at 24 and 48 hours after the initial ibuprofen dose and concomitant treatment with 15 mg/kg oral acetaminophen every 6 hours for 3 days (12 doses). Success of PDA treatment was defined as a small or absent PDA as ascertained by echocardiographic measurements. The p-values of comparisons were adjusted for multiple comparisons to preserve an error rate of 5%. Overall, 20 infants received oral DMT and 11 infants received intravenous single medication therapy (SMT) with ibuprofen. The rates of successful PDA treatment following the first treatment in DMT and SMT groups were not statistically different (11/20 [55%] vs. 4/11 [36%], p = 0.46). However, DMT significantly decreased PDA size (mean difference = 0.54 mm, 95% confidence interval [CI]: 0.21-0.96, adjusted p-value = 0.0002) and PDA/LPA ratio (mean difference = 0.27, 95% CI: 0.10-0.47, adjusted p-value = 0.0004). We observed no evidence of hematologic, hepatic, or renal impairment. DMT achieved a greater degree of PDA closure than SMT and did not result in abnormalities in hepatic and renal profile. · No consensus on optimal medication for PDA treatment is available.. · Dual oral medication therapy (ibuprofen and acetaminophen) could be an effective alternative treatment for PDA.. · Dual oral medication therapy (ibuprofen and acetaminophen) may have a better safety profile than currently approved medications such as intravenous indomethacin and intravenous ibuprofen..

Patent ductus arteriosus (PDA) staging and splanchnic circulation in high risk preterm infants

Objective: To evaluate the influence of PDA on superior mesenteric artery (SMA) and celiac artery (CA) in the immediate postnatal period in preterm infants. Methods: 50 preterm less than 32week with birth weight less than 1kg was included in the prospective observation study. PDA (PSV: peak systolic velocity, EDV: end diastolic velocity, TAV: time average velocity). Blood flow indices (resistive index; RI, pulsatility index; PI) was calculated. PDA was categorized as small, moderate and large. Values taken at 48hr were considered for statistical calculation. Result: Significant PDA was associated with high SMA PSV and low EDV in both SMA and CA. Large (n=12) and moderate PDA (n=3) was associated with high PSV and low EDV in SMA, hence was associated with significantly high RI (large; 0.85±0.04, moderate; 0.80±0.03) in mesenteric circulation. In celiac circulation, large PDA was associated with low EDV (11.66±6.09) and moderate PDA was associated with significant high PSV (64.33±13.05). This velocity pattern in CA was associated with significant high RI (0.77±0.08) and high PI (1.73±0.52) in large PDA group. Velocities in small PDA and no PDA groups were comparable in both arteries. Conclusion: Significant PDA was associated with attenuated blood velocities in SMA compromising the intestinal perfusion. Celiac artery blood flow velocities were adversely affected by large PDA. Low EDV is the predicting factor for compromised perfusion in both the arteries. PDA diameter and flow in descending aorta was the determining factor.

IPEG 2018The 27th Annual Congress for Endosurgery in ChildrenApril 11–14, 2018, Seattle, Washington

IPEG 2018The 27^th Annual Congress for Endosurgery in ChildrenApril 11–14, 2018, Seattle, Washington

EP20.19: Discordant anomalies in monochorionic monoamniotic (MCMA) twin pregnancy

MCMA twin pregnancy accounts for 1-2% of all twin pregnancies and requires close monitoring due to risk of fetal death and cord entanglement. We report a case of MCMA twin pregnancy with discordant anomalies in both fetuses. A 37 year old G3P2 woman, followed at the fetal medicine clinic with MCMA twin pregnancy since 14 weeks of gestation. The woman had no significant past medical or surgical history and had previous two spontaneous vaginal deliveries at term with no complications. Her anomaly scan at 21 weeks gestation showed multiple amniotic bands with normal parameters for both twins and normal amniotic fluid volume. Twin A was diagnosed with a small VSD, partial amelia of both lower limbs and enlarged bladder but with normal kidneys. Twin B with mildly dilated aortic arch but the rest was normal. Fetal echo was performed confirming the findings. The woman was counselled and offered amniocentesis but she declined. She was followed up closely every 2 weeks until 28 weeks where she was admitted in the antenatal word for preterm premature rupture of membranes. She was planned for an elective Caesarean section at 33 weeks gestation but she went into spontaneous labour and had heavy vaginal bleeding. An emergency Caesarean section was performed and confirmed placental abruption with the presence of cord entanglement. The babies were born alive with good Apgar scores and birth weight of 1.6 and 1.8 kg. Both twins were admitted in the neonatal ICU on CPAP. Examination including echo confirmed the antenatal findings with large PDA and small VSD for twin A and small PDA for twin B. Unfortunately on Day 5 of life twin B was desaturating and showed signs of sepsis. The neonate was intubated but died on the same day due to sepsis and pulmonary hemorrhage. Twin A was discharged in a stable condition after 4 weeks and was given a follow-up with orthopedic for management of the lower limb anomaly.

The Amplatzer duct occluder II additional sizes device for transcatheter PDA closure: Initial experience

To present our initial experience with the Amplatzer Duct Occluder II Additional Sizes (ADOIIAS) device. The ADOIIAS is a modified PDA closure device of various lengths and widths with small disks to avoid flow disturbance in the pulmonary arteries and descending aorta. All patients who underwent attempted closure with an ADOIIAS device at our institution CATHETERIZATION: Following aortography the PDA was closed using a 4-5Fr delivery system from the pulmonary or aortic side with an ADOIIAS. Aortography to confirm position and leak was performed before and after device release. Echocardiography was performed before discharge the following day. Between June 2011 and December 2012, 60 patients [33 female], median age 3.3 yrs [0.6-15.8 years], and weight 14.5 kg [4-79] underwent attempted PDA closure with an ADOIIAS device. 56/60 [93.3%] ADOIIAS devices were successfully deployed [52 aortic side]. In 55/56 [98.2%], the PDA was closed on follow up echocardiogram usually on the next day. In one case, there was a small residual PDA of no hemodynamic significance on follow up. In four cases, the ADOIIAS was unstable, including one device embolization which was retrieved with no sequelae, and the PDA was closed in all cases with an alternative device in the same procedure. The mean ratio of ADOIIAS height:PDA pulmonary diameter was 2.4 ± 0.5:1. We report a large single-center experience with the new ADOIIAS device which proved to be versatile, safe, effective, and easy to use in the appropriate ductal anatomy.

Detection of small (≤ 2 cm) pancreatic adenocarcinoma and surrounding parenchyma: correlations between enhancement patterns at triphasic MDCT and histologic features

BackgroundThe aim is to assess the time-density curves (TDCs) and correlate the histologic results for small (≤ 2 cm) PDA and surrounding parenchyma at triphasic Multidetector-row CT (MDCT).MethodsTriphasic MDCT scans of 38 consecutive patients who underwent surgery for a small PDA were retrospectively reviewed. The TDCs were analyzed and compared with histologic examination of the PDA and pancreas upstream/downstream in all cases. Three enhancement patterns were identified: 1) enhancement peak during pancreatic parenchymal phase (PPP) followed by a rapid decline on portal venous phase (PVP) and delayed phase (DP) at 5 minutes (type 1 pattern: normal pancreas); 2) maximum enhancement in PVP that gradually decreases in DP (type 2 pattern: mild chronic pancreatitis or PDA with mild fibrous stroma); 3) progressive enhancement with maximum peak in DP (type 3 pattern: severe chronic pancreatitis or PDA with severe fibrous stroma). A p value less than 0.05 was considered statistically significant. Sensitivity was calculated for PDA detection and an attenuation difference with the surrounding tissue of at least 10 HU was considered.ResultsPDA showed type 2 pattern in 5/38 cases (13.2%) and type 3 pattern in 33/38 cases (86,8%). Pancreas upstream to the tumor had type 2 pattern in 20/38 cases (52,6%) and type 3 pattern in 18/38 cases (47,4%). Pancreas downstream to the tumor had type 1 pattern in 19/25 cases (76%) and type 2 pattern in 6/25 cases (24%). Attenuation difference between tumor and parenchyma upstream was higher of 10 UH on PPP in 31/38 patients (sensitivity = 81.6%), on PVP in 29/38 (sensitivity = 76.3%) and on DP in 17/38 (sensitivity = 44.7%). Attenuation difference between tumor and parenchyma downstream was higher of 10 UH on PPP in 25/25 patients (sensitivity = 100%), on PVP in 22/25 (sensitivity = 88%) and on DP in 20/25 (sensitivity = 80%). Small PDAs were isodense to the pancreas upstream to the tumor, and therefore unrecognizable, in 8 cases (8/38; 21%) at qualitative analysis and in 4 cases (4/38; 10,5%) at quantitative analysis.ConclusionsThe quantitative analysis increases the sensitivity for detection of small PDA at triphasic MDCT.

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Case Reports: A term infant with congenitally corrected transposition of the great arteries (L-TGA) developed respiratory failure shortly after birth, requiring mechanical ventilation. After an extensive workup due to persistent lobar atelectasis and increased congestion unrelated to pneumonia or structural abnormalities, the infant was diagnosed with a genetic disorder uncommonly associated with TGA. Case: Shortly after birth, this infant developed hypoxemia, was intubated, started on a Prostaglandin (PGE) infusion and transferred to our facility for a higher level of care. An echocardiogram revealed L-TGA, large secundum ASD, small PDA, with left-to-right shunt; no dextrocardia or heterotaxy was noted. On hospital day two, the PGE was discontinued and the patient was extubated. He had moderate respiratory distress, intermittent right upper lobe atelectasis and increasing O2 requirement. He improved with high flow nasal cannula oxygen. Diagnostic studies were initiated to explore the etiology of the persistent atelectasis. Laryngoscopy and bronchoscopy revealed a normal airway, with copious thick secretions. CT scan of the chest demonstrated lung atelectasis, a mosaic appearance suggesting air trapping, and normal anatomy without evidence of vascular rings or slings. An MRA confirmed the absence of vascular compression of the airways. Subsequently, a nasal biopsy was performed demonstrating abnormal cilia consistent with primary ciliary dyskinesia (PCD). Genetic sequencing for PCD was sent. Discussion: PCD is an autosomal recessive disease that affects the structure and motility of the cilia, which can result in long-term pulmonary effects. It should be suspected in patients who present with chronic respiratory symptoms in the neonatal period. Although there is a well-known association of PCD with situs inversus, recent research has shown PCD is also associated with heterotaxy and congenital heart disease. Conclusion: A high clinical suspicion should be present for PCD in children with congenital heart disease and persistent respiratory manifestations, such as atelectasis and increased respiratory secretions.

Echocardiographic predictors of symptomatic patent ductus arteriosus in extremely-low-birth-weight preterm neonates

Identify echocardiographic parameters at <or=4 day postnatal that predict the subsequent need for closure of a clinically significant patent ductus arteriosus (sPDA) in extremely-low-birth-weight neonates (ELBW). Serial echocardiograms obtained in 115 ELBW at <or=10 day postnatal were examined to estimate PDA size using the PDA:left pulmonary artery (LPA) diameter ratio: >or=1 indicated a large PDA, <1 but >or=0.5 moderate, and <0.5 small. Sensitivity, specificity, and positive predictive values (PPV) were determined for ELBW <27 weeks and >or=27 weeks gestational age. Neonates with moderate to large PDA at <or=4 day had 15-times greater likelihood of requiring treatment for sPDA than those with a small PDA (95% confidence interval (CI): 5.6-41). Sensitivity, specificity and PPV of the PDA:LPA at <27 weeks was 80, 86 and 92%, respectively. A moderate to large PDA determined from the PDA:LPA ratio at <or=4 day postnatal identifies neonates <27 week gestation who subsequently require closure of a PDA.

Leukocytoclastic vasculitis and myocardial infarction as presenting manifestations of infective endocarditis: a case report

In April 2009, a 32-year-old female patient was referred to our hospital with acute chest pain. She was diabetic, nicotine dependent and had a family history of coronary heart disease. The electrocardiogram showed a previously documented complete left bundle branch block. Cardiac troponin T was elevated (1.18 ng/ml, CK and CK-MB normal, LDH 333 U/l), C-reactive protein serum concentration was 157 mg/l (normal \ 5), white blood count was normal. Coronary angiography showed a thrombotic occlusion of the mid-LAD as culprit lesion (Fig. 1a, left panel). Additionally, a smooth lesion in the small PDA of the right coronary artery could be detected (Fig. 1a, right panel). The patient’s past medical history was complex. Aortic valve replacement with a biological prosthesis had been performed in 2006 due to infective endocarditis. Interestingly, 6 months before the acute coronary syndrome, i.e. in November 2008, the patient had been admitted to an external department with diffuse, non-symmetric arthralgia and a recurrent purpuric rash over her distal lower extremities. Hemorrhagic leukocytoclastic vasculitis had been diagnosed by skin biopsy (Fig. 1b). Laboratory tests conducted at that time had revealed a profound reduction in renal clearance (creatinine 2.4 mg/dl, cystatin C 3.3 mg/l, GFR 16-20 ml/min). Urinanalysis had shown proteinuria (0.84 g/24 h) and glomerular hematuria with detection of acanthocytes. These findings suggest that renal impairment had been caused by a glomerulonephritis. Monotherapy with prednisolone had been performed followed by chemotherapy with cyclophosphamid due to recurrence of symptoms after dose reduction of prednisolone. At the current admission to our department with an acute coronary syndrome, revascularization was performed by direct implantation of a bare metal stent in the midLAD. Because of the small vessel diameter there was no indication for a PCI of the PDA. However, the unusual lesion pattern in two distinct coronary vessels in a young patient with no further evidence of coronary heart disease was highly suspicious for coronary embolism, particularly in the light of the patient’s history of valve replacement 2 years earlier. During admission, the patient was recurrently subfebrile (\38 C), serum concentration of C-reactive protein remained elevated. Transesophageal echocardiography was performed twice. No typical endocarditic vegetations could be detected. However, thickening of the cusps of the bioprosthesis only two years after implantation as well as a mild aortic regurgitation were noticed. Immunosuppressant therapy was stopped. Serial blood cultures drawn at consecutive days yielded Granulicatella adiacens which proved to be highly sensitive to penicillin (MIC 0.004 mg/l). In one additional sample a b-lactamase positive, penicillin-resistant Staphylococcus aureus was obtained which was tested to be sensitive to oxacillin (MIC 0.25 mg/l). These positive microbiological results and the assumed embolic coronary event made the diagnosis of prosthetic valve endocarditis very likely and J. Poss M. Bohm H. Kilter (&) Universitatsklinikum des Saarlandes, Klinik fur Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Kirrberger Strase, 66421 Homburg/Saar, Germany e-mail: heiko.kilter@uks.eu

Flying cake

In the current age of ubiquitous computing via high bandwidth networks, wearable and hand-held mobile devices with small cameras and wireless communication will become widespread in the near future. Thus, research on augmented games for mobile devices has recently attracted a lot of attention. Most existing augmented games use a traditional “backpack” system and “pattern marker”. However, ‘backpack’ systems are expensive, cumbersome, and inconvenient to use, while the use of a pattern marker means the game can only be played at a previously installed location. Hence, this article proposes an augmented game, called Flying Cake , where face regions are used to create virtual objects (characters) without a predefined pattern marker, plus the location of the virtual objects are measured relative to the real world on a small mobile PDA instead of using cumbersome hardware. Flying Cake is an augmented shooting game with two playing modes: (1) single player, where the player attacks a virtual character overlaid on images captured by a PDA camera in the physical world; and (2) two players, where each player attacks a virtual character in an image received via a wireless LAN from their opponent. The virtual character overlaps a face region obtained using a real-time face-detection technique. As a result, Flying Cake provides an exciting experience for players on the basis of a new game paradigm where the user interacts with both the physical world captured by a PDA camera and the virtual world.

Transvenous Embolization of Small Patent Ductus Arteriosus with Single Detachable Coils in Dogs

Transvenous embolization of small patent ductus arteriosus (PDA; ≤ 4 mm) with a single detachable coil was attempted in 24 dogs (median age 5.7 months, range, 2.6–65.5 months; median body weight 5.5 kg, range, 1.5–30.0 kg). Angiographic imaging of the duct and pressure measurements were made before and after embolization. The minimal ductal diameter was 2.7 ± 0.7 mm. In all dogs, a single coil was employed regardless of residual shunting. Ten dogs (PDA minimal diameter range, 1.5‐2.2 mm) received a 5‐mm coil, and 14 dogs (PDA minimal diameter range, 2.9‐3.6 mm) received a 8‐mm coil. After coil embolization the angiographic shunt grade decreased significantly (n = 20,P&lt; .001). Residual shunts were assessed by angiography 15 minutes after and by Doppler echocardiography 1–3 days and 3 months after the intervention. In the dogs treated with the 5‐mm coils the residual shunt rate was low (0%, 10%, and 0% for angiography and Doppler echocardiography at 1–3 days and 3 months, respectively), in contrast to the dogs treated with the 8‐mm coils (91%, 79%, and 67% for angiography and Doppler echocardiography at 1–3 days and 3 months, respectively). After 3 months, no residual murmur was found in dogs treated with the 5‐mm coils (0/7), in contrast to murmurs in 5 of 12 (42%) dogs treated with the 8‐mm coils. Despite incomplete closure in these dogs, volume loading of the left heart decreased in all dogs. Pulmonic or aortic coil embolism did not occur. Analysis of initial results shows that single detachable coil embolization is possible in all dogs with a small PDA (≤ 4 mm), but only very small PDA (s 2.5) could be treated effectively, and for the moderate PDA (2.6‐4.0 mm) longer coils or multiple coils may be necessary to achieve complete occlusion.

Transvenous embolization of small patent ductus arteriosus with single detachable coils in dogs.

Transvenous embolization of small patent ductus arteriosus (PDA; < or = 4 mm) with a single detachable coil was attempted in 24 dogs (median age 5.7 months, range, 2.6-65.5 months; median body weight 5.5 kg, range, 1.5-30.0 kg). Angiographic imaging of the duct and pressure measurements were made before and after embolization. The minimal ductal diameter was 2.7 +/- 0.7 mm. In all dogs, a single coil was employed regardless of residual shunting. Ten dogs (PDA minimal diameter range, 1.5-2.2 mm) received a 5-mm coil, and 14 dogs (PDA minimal diameter range, 2.9-3.6 mm) received a 8-mm coil. After coil embolization the angiographic shunt grade decreased significantly (n = 20, P < .001). Residual shunts were assessed by angiography 15 minutes after and by Doppler echocardiography 1-3 days and 3 months after the intervention. In the dogs treated with the 5-mm coils the residual shunt rate was low (0%, 10%, and 0% for angiography and Doppler echocardiography at 1-3 days and 3 months, respectively), in contrast to the dogs treated with the 8-mm coils (91%, 79%, and 67% for angiography and Doppler echocardiography at 1-3 days and 3 months, respectively). After 3 months, no residual murmur was found in dogs treated with the 5-mm coils (0/7), in contrast to murmurs in 5 of 12 (42%) dogs treated with the 8-mm coils. Despite incomplete closure in these dogs, volume loading of the left heart decreased in all dogs. Pulmonic or aortic coil embolism did not occur. Analysis of initial results shows that single detachable coil embolization is possible in all dogs with a small PDA (< or = 4 mm), but only very small PDA (< or = 2.5) could be treated effectively, and for the moderate PDA (2.6-4.0 mm) longer coils or multiple coils may be necessary to achieve complete occlusion.

Transcatheter coil occlusion of the small patent ductus arteriosus (&lt;4 mm): Improved results with a “multiple coil-no residual shunt” strategy

We report our experience with transcatheter occlusion of the small PDA using Gianturco coils comparing a single coil strategy to a “multiple coil-no residual shunt strategy”. Fifteen patients (Group I) had a single coil only placed irrespective of residual shunting and 20 (Group II) were treated using the no residual shunt strategy. Age, minimal PDA diameter, PDA length and PDA types were similar between groups. Closure rates in Group I patients were 60%, 80% and 87% at <1 month, 6 months and 1 year, respectively. In Group II, the <1 month and 6 month closure rates were 100%. The costs and hospital charges for coil closure were comparable to a concurrent surgical group; the total charges (hospital plus physician) were less for Group I, but similar between Group II and the surgical group. The complication rate for coil closure was significantly less than surgical closure. From these data, transcatheter closure with multiple coils can achieve the same closure rate as surgery at similar hospital charges with fewer complications. Cathet. Cardiovasc. Intervent. 49:307–313, 2000. © 2000 Wiley-Liss, Inc.

System support for mobile, adaptive applications

Imagine that, while on a business trip to Paris, you decide to take a few extra days to sample the city's museums. When you buy your museum pass, you are given a virtual tour guide device-a small PDA that can deliver information about specific pieces in the museum system as well as general information about the city. This device communicates via wireless networks. In or near a museum, the device has access to a high-speed micro-cellular network; in the rest of the city, it makes use of the GSM infrastructure. The user can ask this device to elaborate on specific sites or pieces, display related information, or perform geographically-based queries. These requests are satisfied by applications such as a customized Web browser and a video playback application. When within range of a museum's high-quality network, the displayed information is of excellent quality: images are at high resolution and color, and video is delivered in full motion. However, when the user strays away from the high-bandwidth network, each application degrades the quality of the data it delivers so that it arrives in a timely fashion.

Abnormal cerebral blood flow patterns in preterm infants with a large patent ductus arteriosus

To determine whether there are significant alterations in cerebral blood flow patterns in infants with a patent ductus arteriosus and whether these alterations correlate with alterations in aortic blood flow, we performed range-gated pulsed-Doppler examinations of the aorta and cerebral arteries in 20 infants. Ten infants had a PDA and ten control infants did not. We analyzed these flow patterns quantitatively by calculating the pulsatility index (peak systolic frequency minus trough diastolic frequency)/peak systolic frequency. In the ten control infants and in three infants with a small PDA, there was no significant diastolic flow in the descending aorta; flow in the cerebral arteries was antegrade throughout systole and diastole (PI = 0.75 +/- 0.03 for control infants and 0.73 +/- 0.07 for small PDA infants). In seven infants with a large PDA, there was retrograde diastolic flow in the descending aorta. This pattern was not seen after PDA closure. In the cerebral arteries of the seven infants with a large PDA, diastolic flow was retrograde in three and decreased or absent in four, and PI was significantly higher (PI = 0.96 +/- 0.06. P less than 0.001 vs controls). After PDA closure, cerebral diastolic flow was antegrade in all seven infants (PI = 0.74 +/- 0.04). We conclude that a large PDA can cause abnormal flow patterns in the descending aorta and cerebral arteries. These flow patterns may predispose these infants to CNS ischemia or intraventricular hemorrhage.

The prolonged depolarizing afterpotential and its contribution to the understanding of photoreceptor function.

Comparison of flies bred on vitamine A-poor and vitamine A-rich diets show the latter to exhibit, after blue illumination, 1) slight deviation from the linear relationship between stimulus intensity and receptor sensitivity and, 2) after intense blue illumination the phenomenon of the PDA. Both these effects could result from reduced pigment distances in such membranes. Maximum PDA was produced after about 20 s of illumination with blue light, and following this the resistance of the membrane was seen to stay low, returning to the resting value at the same rate as the PDA decline. The response to test flashes, repressed during illumination, gradually returned during the decline of the PDA, similar to the way the photoreceptor would respond to the sum of two stimuli: the test flash and a decreasing background illumination. Red light immediately following blue abolished the PDA and white light produced a small PDA. All these experiments corroborate a new model (without resorting to the concept of inhibitors) which links the photopigments with receptor excitation, the assumptions for which are the following: 1) PDA is produced after abnormally high primary quantum absorption by rhodopsin molecules, 2) PDA is a retarded membrane excitation by a substance in stored form, 3) the store is built up when production of this substance is larger than its consumption, and 4) time and energy are necessary for the regeneration of excitatory rhodopsin molecules.