Hemolysis following coil embolization of a patent ductus arteriosus

Fabrication of mechanical skeleton of small-diameter vascular grafts via rolling on water surface

Mimicking the multilayered structure of blood vessels and constructing a porous inner surface are two effective approaches to achieve mechanical matching and rapid endothelialization to reduce occlusion in small-diameter vascular grafts. However, the fabrication processes are complex and time consuming, thus complicating the fabrication of personalized vascular grafts. A simple and versatile strategy is proposed to prepare the skeleton of vascular grafts by rolling self-adhesive polymer films. These polymer films are directly fabricated by dropping a polymer solution on a water surface. For the tubes, the length and wall thickness are controlled by the rolling number and position of each film, whereas the structure and properties are tailored by regulating the solution composition. Double-layer vascular grafts (DLVGs) with microporous inner layers and impermeable outer layers are constructed; a microporous layer is formed by introducing a hydrophilic polymer into a polyurethane (PU) solution. DLVGs exhibit a J-shaped stress-strain deformation profile and compliance comparable to that of coronary arteries, sufficient suture retention strength and burst pressure, suitable hemocompatibility, significant adhesion, and proliferation of human umbilical vein endothelial cells. Freshly prepared PU tubes exhibit good cytocompatibility. Thus, this strategy demonstrates potential for rapid construction of small-diameter vascular grafts for individual customization.

Zinc- and Copper-Doped Mesoporous Borate Bioactive Glasses: Promising Additives for Potential Use in Skin Wound Healing Applications

In this study, zinc (Zn)- and copper (Cu)-doped 13-93B3 borate mesoporous bioactive glasses (MBGs) were successfully synthesized using nitrate precursors in the presence of Pluronic P123. We benefited from computational approaches for predicting and confirming the experimental findings. The changes in the dynamic surface tension (SFT) of simulated body fluid (SBF) were investigated using the Du Noüy ring method to shed light on the mineralization process of hydroxyapatite (HAp) on the glass surface. The obtained MBGs were in a glassy state before incubation in SBF. The formation of an apatite-like layer on the SBF-incubated borate glasses was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The incorporation of Zn and Cu into the basic composition of 13-93B3 glass led to changes in the glass transition temperature (Tg) (773 to 556 °C), particle size (373 to 64 nm), zeta potential (−12 to −26 mV), and specific surface area (SBET) (54 to 123 m2/g). Based on the K-means algorithm and chi-square automatic interaction detection (CHAID) tree, we found that the SFT of SBF is an important factor for the prediction and confirmation of the HAp mineralization process on the glasses. Furthermore, we proposed a simple calculation, based on SFT variation, to quantify the bioactivity of MBGs. The doped and dopant-free borate MBGs could enhance the proliferation of mouse fibroblast L929 cells at a concentration of 0.5 mg/mL. These glasses also induced very low hemolysis (<5%), confirming good compatibility with red blood cells. The results of the antibacterial test revealed that all the samples could significantly decrease the viability of Pseudomonas aeruginosa. In summary, we showed that Cu-/Zn-doped borate MBGs can be fabricated using a cost-effective method and also show promise for wound healing/skin tissue engineering applications, as especially supported by the cell test with fibroblasts, good compatibility with blood, and antibacterial properties.

Red blood cell abnormalities occur in dogs with congenital ventricular outflow tract obstruction

OBJECTIVE

To document RBC abnormalities in dogs with congenital ventricular outflow tract obstruction.

ANIMALS

62 dogs with pulmonic stenosis (PS) or aortic stenosis (AS) and 20 control dogs were recruited.

PROCEDURES

The proportions of RBCs that were schistocytes, acanthocytes, and keratocytes were assessed. Complete blood cell counts were performed. Tested variables included hemoglobin concentration, hematocrit, and erythrocyte count.

RESULTS

Median (interquartile range [IQR]) peak systolic Doppler-derived trans-stenotic pressure gradient (∆P) values were 161 mm Hg (108 to 215 mm Hg) and 134 mm Hg (125 to 165 mm Hg) for dogs with PS and AS, respectively. Hematologic abnormalities were detected in most dogs with AS or PS (54/62 [87%]) versus 8/20 [40%] in control dogs, with schistocytes found in 40 of 62 (65%; median, 0.1% RBCs; IQR, 0% to 0.3%), acanthocytes in 29 of 62 (47%; median, 0.3% RBCs; IQR, 0% to 0.9%), keratocytes in 39 of 62 (63%; median, 0% RBCs; IQR, 0% to 0.2%), and hemolytic anemia in 4 dogs with PS. No significant association was identified between these abnormalities and ∆P. However, 3 of 4 dogs with anemia had a ∆P > 200 mm Hg (range, 242 to 340 mm Hg). The dog with the highest ∆P value also had the most severe anemia and schistocytosis, and both resolved after balloon valvuloplasty.

CLINICAL RELEVANCE

Poikilocytosis is common in dogs with congenital ventricular outflow tract obstruction, with anemia only observed in few dogs with high ∆P values.

Expectant management of prolonged hemolysis following complete transcatheter coil closure of a patent ductus arteriosus after previous pulmonary artery banding: a case report

Background

Transcatheter coil occlusion has been the treatment of choice for closure of small patent ductus arteriosus (PDA). In spite of its safety, complications such as hemolysis still occasionally occur. And the hemolysis almost always occurs following partial transcatheter closure of PDA; hence, it occurs extremely rarely following complete transcatheter closure of PDA without residual ductal flow.

Case presentation

Here, we describe a male newborn who developed prolonged hemolysis following complete transcatheter coil closure of his PDA after previous palliative pulmonary artery banding. Over the following days, we corrected his refractory anemia by repeated blood transfusion with packed red blood cells and frequently monitored his hemoglobin, serum total bilirubin, and serum lactate dehydrogenase. We speculated that the high-velocity pulmonary blood flow jet coming into contact with the extruded part of the coil led to red blood cell mechanical injury, thereby resulting in the hemolysis. We adopted expectant management in expectation of the endothelialization of the coil with a resultant reduction in the hemolysis. The hemolysis, as expected, was reduced gradually until it spontaneously resolved 81 days after coil implantation.

Conclusions

This case reminds us that hemolysis can still potentially occur following complete transcatheter coil closure of PDA. It also highlights the importance of preventing coils from extruding into the pulmonary artery in patients after previous pulmonary artery banding.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02365-z.

Selenium-containing polyurethane with elevated catalytic stability for sustained nitric oxide release

Stable and controllable nitric oxide (NO) release at the physiological level from biomedical materials remains a challenge for NO-based therapy. NO-generating polymers have great potential to achieve this goal because they can catalytically decompose endogenous S-nitrosothiols (RSNOs) into NO. However, the current catalytic surfaces based on such polymers often suffer from loss of catalytic sites, which can influence the stability of NO release in their long-term application. In this work, we proposed a novel strategy to enhance the catalytic stability of NO-catalytic materials by incorporating catalytic sites into the polymer backbone. Selenium-containing polyurethane (PU-Se) was synthesized by using the catalyst 2,2'-diselenodiethanol (SeDO) as the chain extender. A series of PU/PU-Se blend films were prepared to investigate the effect of PU-Se content on the catalytic properties. The blend films exhibited excellent catalytic activity, and also showed outstanding catalytic stability in comparison with PU coated by diselenide/dopamine (PU-PDA-Se). Among these blend films, PU-Se-10 exhibited a stable NO release rate of 5.05 × 10^-10 mol cm^-2 min^-1 after exposure to PBS buffer for 30 days. Moreover, the PU/PU-Se films exhibited decreased platelet activation/adhesion, low hemolysis ratio, excellent biocompatibility, and similar mechanical properties to PU. It is expected that the newly designed PU-Se has great potential in generating stable NO release at the physiological level for the long-term application of blood-contacting medical devices.

Chemical modification of poly(vinyl chloride) for blood and cellular biocompatibility

Poly(vinyl chloride) (PVC) was modified with three different ionomers including thiosulphate, thiourea and sulphite for improving the biocompatibility of the polymer.

Influence of Layer-by-Layer Polyelectrolyte Deposition and EDC/NHS Activated Heparin Immobilization onto Silk Fibroin Fabric

To enhance the hemocompatibility of silk fibroin fabric as biomedical material, polyelectrolytes architectures have been assembled through the layer-by-layer (LbL) technique on silk fibroin fabric (SFF). In particular, 1.5 and 2.5 bilayer of oppositely charged polyelectrolytes were assembled onto SFF using poly(allylamine hydrochloride) (PAH) as polycationic polymer and poly(acrylic acid) (PAA) as polyanionic polymer with PAH topmost. Low molecular weight heparin (LMWH) activated with 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) was then immobilized on its surface. Alcian Blue staining, toluidine blue assay and X-ray photoelectron spectroscopy (XPS) confirmed the presence of heparin on modified SFF surfaces. The surface morphology of the modified silk fibroin fabric surfaces was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and obtained increased roughness. Negligible hemolytic effect and a higher concentration of free hemoglobin by a kinetic clotting time test ensured the improved biological performance of the modified fibroin fabric. Overall, the deposition of 2.5 bilayer was found effective in terms of biological and surface properties of the modified fibroin fabric compared to 1.5 bilayer self-assembly technique. Therefore, this novel approach to surface modification may demonstrate long term patency in future in vivo animal trials of small diameter silk fibroin vascular grafts.

Thromboresistant and endothelialization effects of dopamine-mediated heparin coating on a stent material surface

Heparinization of surfaces has proven a successful strategy to prevent thrombus formation. Inspired by the composition of adhesive proteins in mussels, the authors used dopamine to immobilize heparin on a stent surface. This study aimed to assess the thromboresistant and endothelialization effects of dopamine-mediated heparin (HPM) coating on a stent material surface. The HPM was synthesized by bonding dopamine and heparin chemically. Cobalt-chromium (Co-Cr) alloy disks were first placed in the HPM solution and applied to surface stability then underwent thromboresistant tests and human umbilical vein endothelial cells (HUVEC) cytotoxicity assays. The results showed not only thromboresistant activity and a stable state of heparin on the surfaces after investigation with toluidine blue and thrombin activation assay but also proliferation of HUVEC in vitro. Studies on animals showed that the HPM-coated stent has no obvious inflammation response and increasing of restenosis rate compared to the bare metal stent (BMS) indicating good biocompatibility as well as safety in its in vivo application. Moreover, improving the endothelial cell (EC) proliferation resulted in a higher strut-covering rate (i.e., endothelialization) with shuttle-shaped EC in the HPM-coated stent group compared to that of the BMS group. These results suggest that this facile coating approach could significantly promote endothelialization and offer greater safety than the BMS for its much improved thromboresistant property. Moreover, it may offer a platform for conjugating secondary drugs such as anti-proliferative drugs.

Investigation of polymeric amphiphilic nanoparticles as antitumor drug carriers

In this paper, polymeric amphiphilic nanoparticles based on oleoyl-chitosan (OCH) with different degrees of substitution (DS, 5%, 11% and 27%) were prepared by Oil/Water emulsification method. Mean diameters of the nanoparticles were 327.4 nm, 255.3 nm and 192.6 nm, respectively. Doxorubicin (DOX) was efficiently loaded into OCH nanoparticles and provided a sustained released after a burst release in PBS. These nanoparticles showed no cytotoxicity to mouse embryo fibroblasts (MEF) and low hemolysis rates (<5%). The results of SDS-PAGE indicated that bovine calf serum (BCS) adsorption on OCH nanoparticles was inhibited by smaller particle size. Cellular uptake was evaluated by incubating fluorescence labeled OCH nanoparticles with human lung carcinoma cells (A549) and mouse macrophages (RAW264.7). Cellular uptake of OCH nanoparticles was time--and concentration--dependent. Finding the appropriate incubation time and concentration of OCH nanoparticles used as drug carriers might decrease phagocytic uptake, increase cancer cell uptake and ultimately improve therapeutic efficiency of antitumor therapeutic agents.

Investigation on clotting and hemolysis characteristics of heparin-immobilized polyether sulfones biomembrane

In this study, a novel heparin-immobilized polyethersulfone (PES) was synthesized. PES was initially sulfonated with chlorosulfonic acid and then 1,6-hexanediamine was grafted to the -SO(3)H groups of sulfonated PES, which subsequently reacted with heparin through a covalent bond by using (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) as catalyst. The hydrophobic/hydrophilic property was characterized by measuring the water contact angle. The data shows decline from 62.29 degrees +/- 1.2 degrees to 47.86 degrees +/- 0.3 degrees for water and 86.79 degrees +/- 0.8 degrees to 68.34 degrees +/- 1.0 degrees for glycerol, which indicates an enhancement of hydrophilicity. Plasma hemolysis assay shows a comparatively low hemolysis ratio of 1.04%, which is below permissible limit of 5%. A higher content of dissociated blood cells and Ca(2+) concentration was found in red blood cell counting and coagulation factor IV test in heparinized PES. Plasma recalcification time of 360 s also offers positive evidence that heparinized PES seems to have a good anticoagulation property. This new heparin-immobilized PES biomaterials may have the potential for biomedical applications.

Preparation and blood coagulation evaluation of chitosan microspheres

Cross-linked chitosan microspheres (40-100 microm) with smooth surface were prepared by the methods of emulsification and ethanol coagulant. FTIR results showed that the cross-linking reaction occurred on the amino groups of chitosan molecules. The swelling characteristic of chitosan microspheres was influenced by the environment pH, being generally greater at low rather than higher pH values. The coagulation properties of chitosan microspheres were evaluated by dynamic blood clotting, platelet adhesion and activation, erythrocyte adhesion, hemolysis, and protein absorption assays. Chitosan microspheres can shorten the clotting time and induce the adhesion and activation of platelets. But the shortening of clotting time by chitosan microspheres may be related to not only platelet aggregation, but also erythrocyte aggregation. Take together, chitosan microspheres may be potential use as thrombospheres.

Study on Adhesion and Biocompatibility of Copolymer of MMA-BMA-MAA for Coronary Stents Coatings

Implantation of drug releasing coronary stents has been developed as an useful method for prevention of the restenosis in blood vessels. Copolymers of methyl methacrylate (MMA), butyl methacrylate (BMA) and methacrylic acid (MAA) were prepared as the coating polymer for drug releasing stent. The adhesion of the polymer with metal substrate and the biocompatibility were studied. Effect of the polymer composition on the adhesion between polymer coatings and metal substrate, as well as the effect of the polymer purification method on biocompatibility of the polymer, was studied. The results showed that the copolymer coating has good dry and wet adhesion properties, which can be improved by control of the polymer compositions. Biocompatibility of the prepared copolymer comes within the permission limit.

The modern approach to patent ductus arteriosus treatment: complementary roles of video-assisted thoracoscopic surgery and interventional cardiology coil occlusion

BACKGROUND

In an effort to analyze our experience and develop treatment guidelines, we reviewed all our patients with patent ductus arteriosus (PDA) treated with video-assisted thoracoscopic surgery (VATS) or interventional cardiology coil occlusion.

METHODS

One hundred patients underwent 102 cardiac catheterizations. Forty-five children underwent VATS. The entire cohort of patients is 141 because 4 patients underwent both catheterization and VATS.

RESULTS

Successful PDA coil occlusion occurred in 91 patients (91 of 100; 91%); 8 had unsuccessful attempts at coil occlusion and 1 was referred for surgical ligation after catheterization without any attempt at coil placement. Thirty-nine children had successful VATS PDA closure. Six children required conversion to thoracotomy because of inadequate exposure during VATS. Hospital stay for children more than 45 days of age was as follows: VATS median stay, 1 day, mean, 1.4 days; thoracotomy median stay, 4 days, mean, 4.6 days. One patient treated with PDA coil occlusion developed a recurrent PDA and required reembolization. Three children underwent initial catheterization without successful coil placement with subsequent successful VATS. All VATS patients left the operating theater with echocardiography documenting no residual PDA. Two children who underwent successful VATS with no residual PDA at hospital discharge were found on outpatient follow-up to have developed tiny recurrent PDAs and both were successfully coil occluded; 1 of these 2 children is 1 of the 3 children initially evaluated by catheterization and then referred for VATS.

CONCLUSIONS

Video-assisted thoracoscopic surgery and coil occlusion represent complementary techniques for PDA treatment. A rationale for selection of the appropriate treatment modality can be based upon the size and age of the patient and the size and morphology of the PDA.

Synthesis, characterization, and blood compatibility of polyamidoamines copolymers

This work reports the development of new non-thrombogenic polymers based on the linear polymers of polyamidoamines (PAAs), having heparin binding ability, obtained by polyaddition of secondary amines to N,N'-methylene bis-acrylamide. PAAs could not be used directly in the making of blood-contacting materials due to their poor mechanical strength. In order to overcome this lacuna, copolymers of amidoamine with methylmethacrylate (MMA) were prepared. Characterization studies indicated that the PAAs have been suitably incorporated into the MMA matrix. The relative hydrophilic nature of the synthesized copolymers was established from the measurement of water contact angle. The heparinized copolymers showed significant improvement in non-thrombogenic characteristics.

Synthesis of blood compatible polyamide block copolymers

Blood compatibility of polyamides has been improved by introducing amido-amine groups in polymer backbone. Polyamide block-copolymer are synthesized by reacting amine end-capped polyamides with N,N'-methylene-bisacrylamide. Polyamide block-copolymers, thus produced found to have the ability of absorbing heparin. Heparinized polyamide block-copolymers have shown significant improvement in blood compatibility as evident from thrombus formation and hemolysis studies.

Severe intravascular hemolysis after transcatheter closure of a large patent ductus arteriosus using the Amplatzer duct occluder: successful resolution by intradevice coil deployment

A 21-year-old female developed severe unremitting intravascular hemolysis following closure of a large patent ductus arteriosus using an Amplatzer duct occluder. Percutaneous deployment of fibered platinum coils within the nitinol wire cage of the Amplatzer duct occluder abolished the residual shunt through the device and resulted in cessation of intravascular hemolysis and reversal of its adverse sequelae.

Closure of prosthetic paravalvular mitral regurgitation with the Gianturco-Grifka vascular occlusion device

Paravalvular regurgitation associated with prothetic mitral valves is often a consequence of infectious endocarditis. The condition is usually treated with debridement and repeat surgical valve replacement. However, repeated operations are associated with high risk. This report describes a case of successful transcatheter treatment of severe paravalvular mitral regurgitation and pulmonary edema in a patient in whom repeat mitral valve replacement was not believed possible.

Conservative treatment of hemolytic complication following coil embolization in two adult cases of patent ductus arteriosus

Two adult cases of relatively large patent ductus arteriosus (PDA) were treated by coil embolization, but were complicated by hemolysis that was successfully managed by medical treatment. Case 1 was a 67-year-old woman and Case 2 was a 71-year-old woman with a PDA of minimal diameter of 5.3 mm and 5.5 mm, respectively. The approach was via the pulmonary artery and 2 coils were delivered simultaneously into the ductus, known as the 'kissing coil technique'. Although immediately after the procedure only a small residual shunt was revealed by aortogram, hemolysis occurred for several hours after the procedure in both cases. A hemolytic complication usually needs additional coil embolization or surgical treatment, but in these 2 cases it was successfully treated by haptoglobin infusion to prevent nephropathy and by antiplasmin infusion to promote thrombus formation. Hemolytic complications of coil embolization of PDA can managed by medication when the residual shunt is minimal and the degree of hemolysis is mild.

Anterograde coil closure of patent ductus arteriosus using a modified bioptome delivery technique

Three consecutive patients are presented who underwent successful anterograde catheter coil occlusion of a patent ductus arteriosus using a modified bioptome-assisted technique. Two of the three patients were infants and the procedures were performed without the need for arterial access.

[Interventions in congenital heart disease and their sequelae in adults]

The advancements of cardiac surgery over the last decades led to larger numbers of patients with operated congenital heart diseases surviving into adulthood. In Germany it is estimated that over 120,000 adults have operated congenital heart diseases. Five to 7% of them will need yearly hospital admissions. Interventional procedures are additional tools used to treat these patients with various sequelae or residua (Table 1). In the following review we concentrate on 2 different interventional procedures: dilatation and stent implantations for treatment of stenosis and the different devices used for the closure of shunt lesions. For congenital valvular pulmonary stenosis, balloon dilatation is the therapy of choice regardless the age of the patient. Stent implantation for the treatment of peripheral pulmonary stenosis (e.g., after previous systemic pulmonary shunts) can decrease the need for redo surgery, which is accompanied with increased risk. Stent implantations proved also to be useful to treat stenoses after Mustard patch in patients with transposition of the great arteries, after Fontan procedures or dealing with the rare pulmonary venous stenosis. In contrast, dilatation of bioprosthesis and conduit stenosis are not promising. Balloon dilatation of valvular aortic stenosis is an accepted therapy in childhood up to adolescents. Table 2 compares a surgical series including many infants with critical aortic stenosis with a series of balloon dilatation in children and another one in adults regarding lethality, complications, and results. Table 3 illustrates the immediate and late results of balloon dilatation of aortic coarctation in 3 different studies. The high recurrence rate in infants made clinicians refrain from taking this age group for balloon dilatation. In children and adult patients, good results are reported (75% reduction of gradients). The complication rate is low (2.3 to 3.3%) and aneurysm formation rate seldom (1 to 7%). Stenosed aorto-pulmonary collaterals will rarely need balloon dilatation. Surgical closure of atrial septal defect is a low risk procedure with a very low rate of residual shunts (2%). Of the 5 available devices for transcatheter closure of atrial septal defect Type II, only 2 occluders are in use in Germany, the Clamshell and the Amplatzer device. The largest clinical studies of the different systems, their efficacy, complications and residual shunt rate are presented in Table 4. For the deployment of these occluders a TEE is always needed. There are many more systems in clinical use to close the patent arterial duct (PDA) (Table 5). The Ivalon plug as well as the Rashkind device have probably only historical value. Different types of coils (Gianturco, Cook detachable, PFM) are now in use worldwide. The reason for their widespread use, besides their easy application, is the fact that most coils are relatively cheap and need only small sheaths for deployment. Their further evaluation identified a residual shunt rate of 5% as well as a number of complications (embolization, hemolysis, stenosis of the left pulmonary artery) in 0 to 6%. For the large PDA the Amplatzer device has recently been introduced. An additional indication for the use of the different occluding devices are aorto-pulmonary collaterals, venovenous fistulae, pulmonary or coronary artery fistulae. Aorto-pulmonary collaterals are often associated with complex cardiac lesions and occasionally appear after palliative procedures. An excellent cooperation between adult and pediatric cardiologists is needed in order to offer the group of adults with congenital heart diseases an adequate and comprehensive management.

Haemolysis following implantation of duct occlusion coils

OBJECTIVES

To describe the incidence and management of haemolysis after transcatheter coil occlusion of the arterial duct.

DESIGN

Prospective clinical and echocardiographic follow up of patients who have undergone implantation of the Cook detachable duct occlusion coil.

SETTING

Tertiary paediatric cardiac centre.

PATIENTS

Five cases of haemolysis (two girls aged 6 and 11 months; three boys aged 6, 17, and 14 months) from a series of 137 duct coil implantations.

MAIN OUTCOME MEASURES

The occurrence of clinically significant haemolysis after implantation of duct occlusion coils and resolution of haematuria after completion of duct occlusion.

RESULTS

Haemolysis was detected in five of 137 procedures following implantation of Cook detachable duct coils. Four patients became symptomatic 12 hours after the procedure but in one haemolysis was detected three months later. Resolution of ongoing haemolysis was achieved within 48 hours of detection with further coil implantations, but haematuria persisted for up to 10 days. In one patient the extensive destruction of erythrocytes resulted in acute renal failure requiring peritoneal dialysis.

CONCLUSIONS

Haemolysis is an important complication after duct coil implantation. It occurred in 3.6% of 137 procedures in this series and is most likely to occur in young patients with relatively large ducts. Further coil implantation to occlude the duct completely is not only successful but technically relatively straightforward and should be undertaken early if major complications such as severe anaemia and renal failure are to be avoided.

Transcatheter occlusion of patent ductus arteriosus with a new detachable coil system (DuctOcclud): a multicenter clinical trial

A multicenter clinical trial of DuctOcclud, a new detachable coil for transcatheter occlusion of patent ductus arteriosus (PDA), was conducted. DuctOcclud was used in 35 patients (12 male and 23 female) for transcatheter occlusion of PDA between January, 1996, and April, 1997. The age of the patients ranged from 0.5 to 27.2 years (median 7.6 years) and weight from 6.3 to 70.0 kg (median 23.0 kg). The smallest diameter of PDA was 2.0+/-0.7 mm (range 1.0-3.3 mm). Pulmonary-systemic flow ratio (Qp/Qs) was 1.3+/-0.3 (range 1.0-2.2). The coils were successfully implanted in 32 (91%) patients. Of 31 patients who were followed 6 months after the procedure, 26 (84%) had no residual shunt and 5 (16%) had trivial residual shunt. One patient had infective endocarditis 1 month after the procedure but recovered completely. There were no incidences of coil embolization, hemolysis, late coil migration, or pulmonary artery stenosis. We conclude that DuctOcclud is a safe and effective device of transcatheter occlusion of PDA.

Hemolysis complicating coil occlusion of patent ductus arteriosus

We report on 5 patients who developed hemolysis (the Hemolysis group) following coil occlusion for PDA, and compare their data to 66 cases which were not complicated by hemolysis despite residual leak (the No Hemolysis group). A significant leak with a heart murmur was more frequent in the Hemolysis group than in the No Hemolysis group. The ratio of the sum of the loop diameter of coils to the minimal diameter of the ductus (C/D) in those who developed persistent hemolysis that needed a second intervention (2.2+/-0.4) was significantly smaller than in the No Hemolysis group (3.1+/-1.1). Persistent hemolysis can occur if a significant residual shunt remains after implantation of coils with small C/D. As this complication may be avoided by complete closure or, if not complete, a minimal leak, we should be careful to make residual leaks as small as possible by the use of multiple coils.

Coil occlusion for patent ductus arteriosus in Japan

We surveyed Japanese experience of coil occlusion of patent ductus arteriosus up to 30 September 1996 by sending questionnaires to 175 hospitals. Thirty-four hospitals reported outcome data for 231 procedures in 218 patients. Successful implantation was achieved in 94% and acute complete closure of the ductus occurred in 71% of those in whom implantation of the coil was successful. Of the latter, 83% reported late complete closure. When those patients who underwent reocclusion for residual shunt are included, 89% attained complete closure. No life-threatening complications have occurred so far. Late reopening was reported in 3 cases. Although the angiographic type of ductus was significantly related to successful implantation (p < 0.01), there was no significant correlation with complete occlusion. Ductuses with a minimum diameter greater than 3 mm had a decreased chance of successful implantation, whereas those less than 2 mm had a greater incidence of complete closure.