Comparison of two transcatheter device strategies for occlusion of the patent ductus arteriosus

Objectives: The present study evaluates two transcatheter closure strategies utilized at a single center and makes recommendations for device selection when occluding the patent ductus arteriosus. Background: A variety of devices are available for transcatheter closure of the patent ductus arteriosus (PDA) but no guidelines exist to guide operator device choice. Methods: A total of 132 patients underwent attempted transcatheter PDA closure utilizing one of two consecutive closure strategies between January 2000 and June 2005. Strategy A (n = 64; January 2000–May 2003) utilized Gianturco coils only. Strategy B (n = 68; June 2003–June 2005) utilized a single Gianturco coil for the PDA with a minimal diameter ≤1 mm (n = 28) or an Amplatzer Duct Occluder (ADO) if the PDA diameter exceeded 1 mm (n = 40). Success was defined as complete occlusion on a follow up echocardiogram. Results: 58 of 64 (90.6%) patients treated utilizing strategy A had successful coil implantation. 68 of 68 (100%) patients treated utilizing strategy B had successful coil/device implantation. At follow up echocardiography, 32 of 44 (72.7%) strategy A patients had complete ductal closure, as compared with 57 of 58 (98.3%) strategy B patients (P < 0.0001). Stepwise logistic regression analysis identified closure strategy as the most powerful predictor of procedural success (OR = 85.9; CI 5.6–9.99). Conclusions: A transcatheter PDA closure strategy consisting of a single Gianturco coil for PDA ≤ 1 mm or an ADO for larger sized PDA (strategy B) achieves superior outcomes compared to the use of coils alone. © 2008 Wiley‐Liss, Inc.     

Safety and efficacy of using 0.052-inch Gianturco coil for closure of large ( > or = 4mm) patent ductus arteriosus

Transcatheter closure of patent ductus arteriosus (PDA) is now a well-established treatment alternative to surgery in many cardiology centers. Of all the methods used, transcatheter coil occlusion is the preferred therapy. For small PDA, the method using 0.038" Gianturco coils has proven safe and effective. However, this therapeutic strategy has encountered some difficulties with large PDA. This study provides an alternative strategy, using 0.052" Gianturco coil and complete closure of residual shunt with multiple coils to close large PDA. Fifteen patients underwent transcatheter coil occlusion of large ( > or = 4mm) patent ductus arteriosus. The intermediate success rate was 86.7%. There were four complications and only two patients had to be referred for surgery.     

Comparison between the safety profile and clinical results of the Cook detachable and Gianturco coils for transcatheter closure of patent ductus arteriosus in 272 patients

OBJECTIVES: We evaluated the occlusion rate and safety of Cook detachable coils versus Gianturco coils in transcatheter closure of patent ductus arteriosus (PDA). BACKGROUND: The Cook detachable coil recently was introduced in an attempt to improve the safety of transcatheter closure of PDA. METHODS: Between January 1994 and September 1998, 272 patients underwent transcatheter PDA closure. Cook detachable coils were used in 137 patients, with a mean age of 43.9 months and weight of 13.8 kg. In 135 patients, Gianturco coils were used, with a mean age of 56.8 months and weight of 17.8 kg. The mean narrowest diameter of the PDA in the Cook detachable coil group was 2.85 mm versus 2.32 mm for the Gianturco coil group. RESULTS: The Cook detachable coil group was younger and weighed less than the Gianturco group (P < 0.05 and 0.02, respectively). Their narrowest PDA diameter was larger (P < 0.01). Embolization rate was significantly lower in the Cook coil group (9[6.5%] of 137 vs 22 (16.3%) of 135; P = < 0.013). The mean follow-up for the Cook coil group was significantly shorter (0.55 years) than for the Gianturco coil group (1.18 years; P < 0.001). On an intention-to-treat basis, complete occlusion by echocardiography was achieved in 99 (72.3%) of 137 patients in the Cook detachable coil group, which was significantly less than the Gianturco coil group (114 [84.4%] of 135; P = 0.008). CONCLUSION: Cook detachable coils for transcatheter closures of the PDA are safer than Gianturco coils. Hence, children with large ductal can be treated earlier in life. Short-term complete occlusion rate was lower in the Cook detachable coil group. This rate can be explained by a shorter follow-up time, larger ductal diameter, and the different materials used for the detachable coils.     

Trans‐catheter closure of patent ductus arteriosus—What is the best device?

Background : Over the past three decades, transcatheter occlusion of patent ductus arteriosus (PDA) has evolved to be the procedure of choice. Gianturco and Flipper coils are the most commonly used coils in the United States for closure of small and moderate size PDAs. For larger PDAs, interventionalists in the United States commonly use the Amplatzer Duct Occluder (ADO) and those in Europe use the ADO or the Nit‐Occlud Coils (NOC). A comparison between Gianturco coils, Flipper coils, ADO, and NOC has never been made. Objective : To compare the success and complication rate associated with the four different devices used for transcatheter closure of PDA. Success was defined as complete closure of PDA with absence of a residual shunt (R.S.) at six months follow‐up. Methods : Two institutions collaborated in combining their data to evaluate the results of transcatheter closure of PDA. Results : Totally, 546 patients underwent successful PDA occlusion at both institutions. Gianturco and Flipper coils were used in 120 (22%) and 119 (22%) patients respectively. A total of 152 (28%) patients received ADO and 155 (28%) patients received NOC. Immediate R.S. were noted in 226 (41.4%) patients in the entire study group with the NOC group having the highest percentage of R.S. (80/155, 51.6%, P = 0.004). Of the 484 patients with follow‐up echocardiograms at 6 months, 35 (7.2%) patients had persistent R.S. The NOC (3/143, 2.1%) and ADO (5/150, 3.3%) groups had the least R.S. at six months follow‐up. Conclusion : Per our definition of success, the Nit‐Occlud coils and the Amplatzer duct‐occluder devices had significantly higher success rate for PDA occlusion versus the coils. © 2010 Wiley‐Liss, Inc.     

Long-term outcome comparison between rashkind umbrella and gianturco coils occlusion in native patent ductus arteriosus

Background: The Rashkind Umbrella device has proven effective in closing small to moderate size patent ductus arteriosus. A comparable early occlusion rate was also seen in PDA occlusion using Gianturco coils. This study addresses the long-term outcome of both techniques in a single centre. Methods: Review was undertaken of 522 patients with PDA who underwent transcatheter occlusion before January 1997; 244 patients (mean: age 8.0±6.7 years, weight 21.8±12.9 kg, PDA size 3.2±1.0 mm) were intended to receive the Rashkind Umbrella device and the remaining 278 patients (mean: age 6.4±5.6 years, weight 18.6±11.2 kg, PDA size 2.5±1.0 mm) would receive Gianturco coils. Deployment failure occurred in 8 patients (3%) and 6 (2%) during the initial learning curve of the Rashkind Umbrella and Gianturco coil, respectively. In the Rashkind Umbrella group, haemolysis occurred in 6, device embolisation in 3, and 1 patient died from anaesthetic sequelae. Peripheral pulmonary embolisation of coils occurred in 7 patients and all were successfully retrieved. Results: Results were analysed from 228 and 258 patients who had successful Rashkind Umbrella device and Gianturco coil deployment respectively. All had completed at least 1 year follow-up. They were evaluated clinically for residual ductal murmur and echocardiographically for a residual ductal shunt and presence of pulmonary artery or aortic obstruction. The Rashkind Umbrella group had significantly higher residual shunt compared to the Gianturco coil group at various stages of follow-up (p<0.05), 40% v 22% at 24 hours, 29% v 7% at 3 months, 25% v 4% at 6 months and 22% v 3% at 1 year. In 57 patients, a reocclusion procedure during the study period was undertaken to effect immediate complete occlusion. Mild left pulmonary artery stenosis (velocity<2 m/s) was noted in 6 patients who had multiple coils and one who had a 17 mm Rashkind Umbrella device. Conclusions: Transcatheter occlusion of PDA using the Gianturco coil is safer and more effective than the Rashkind Umbrella device. It has become the first choice for treating small to moderate size native PDA at our institution.     

经导管封堵动脉导管未闭外科及介入治疗术后残余分流

目的 评价经导管封堵动脉导管未闭(PDA)外科结扎及介入治疗术后残余分流的效果.方法 1995年6月至2008年9月,42例外科结扎、1例外科结扎术后又行弹簧栓子法、3例Rashkind法及1例Sidires法介入治疗术后残余分流的PDA患者施行了经导管封堵术,其中男9例,女38例,年龄2～53岁,平均25.0±15.5岁.外科手术至介入治疗的时间为1个月～30年,其中1例曾行两次外科结扎术.第一次介入治疗至本次封堵术的时间为4年～14年.43例经股静脉途径植入封堵器,其中2例采用动静脉轨道法;2例经股动脉途径植入可控弹簧栓子.介入术后24 h～7.8年行X线胸片、心电图及超声心动图随访.结果 残余分流的PDA最窄处直径为1～10 mm,平均4.1±2.0 mm.技术成功率为95.7%(45/47).45例封堵术后10 min.主动脉弓降部造影示无残余分流40例(88.9%),微量残余分流4例(8.9%),少量残余分流1例(2.2%).术后24 h经胸超声心动图示无残余分流44例(97.8%),少量残余分流1例(2.2%),该例术后9 h发生溶血,经保守治疗1周后消失.失败2例,植入封堵器后仍有明显残余分流,收回封堵器,终止介入治疗.本组45例随访1个月～7.8年,除1例于术后4个月发生心房颤动外,余未发现封堵器移位、残余分流及细菌性心内膜炎.结论 经导管封堵动脉导管未闭外科结扎及介入治疗术后的残余分流是一种创伤小、成功率高、并发症少、住院时间短、安全有效的方法,基本可以替代外科手术.     

Radiographic characteristics of Cook detachable and Gianturco coils as well as clinical results of transcatheter closure of the patent ductus arteriosus

PURPOSE: To describe the radiographic appearance of the Gianturco and the Cook detachable coils and present the clinical results in patients who underwent transcatheter closure of patent ductus arteriosus. MATERIALS AND METHODS: Between January 1994 and June 1997, eighty-two patients underwent closure of patent ductus arteriosus (PDA) using either Gianturco or Cook detachable coils. The chest x-ray and echocardiography of all patients were reviewed and the following parameters were evaluated: 1) the size of the heart (cardiothoracic ratio), 2) the position and the type of the coils in the postero-anterior and the lateral projection, 3) the number of coils used, 4) the existence of residual ductal flow, 5) Doppler velocity in the left pulmonary artery. RESULTS: Complete occlusion was achieved in 94%, and cardio-thoracic ratio regressed from 0.57 to 0.53 (p < 0.01), after a mean follow-up of 1.2 years. The identification of the different coils on the chest radiograph was successful in only 47% of cases, difficulties arising especially, when multiple coils were used. In 55 patients (67%) the coil position was judged to be optimal, in 27 patients (33%) suboptimal. The latter correlates with the presence of residual shunt. Multiple coils correlated more with a left pulmonary artery flow velocity exceeding 1.5 m/s. CONCLUSION: Coil-occlusion of patent ductus arteriosus is effective and leads to reduced cardio-thoracic ratio. Radiographic coil identification is possible but may be difficult if multiple coils are deployed. Suboptimal coil position led more often to residual PDA shunt. Multiple coils are more commonly associated with increased LPA velocities, but hemodynamic significant obstruction to flow is rare.     

Additional aortopulmonary collaterals in patients referred for coil occlusion of a patent ductus arteriosus

Coexisting aortopulmonary collaterals in patients diagnosed with a patent ductus arteriosus (PDA) are rare findings. Percutaneous transcatheter closure of PDA and requisite aortography offer an unique opportunity to identify and treat these systemic arterial anomalies, which would be missed by echocardiographic evaluation alone. The significance of these collaterals is unclear, but it may contribute to left heart dilation from additional left to right shunting in patients with an otherwise isolated small PDA. Of 18 patients undergoing transcatheter occlusion of a PDA with Gianturco coils, 2 were found to an additional significant aortopulmonary collaterals, which were also occluded. © 1996 Wiley-Liss, Inc.     

Angiographic and hemodynamic predictors for successful outcome of transcatheter occlusion of patent ductus arteriosus in infants less than 8 kilograms.

Transcatheter occlusion of patent ductus arteriosus (PDA) using Gianturco coils (GCs) has been performed for the past decade. However, little has been written regarding anatomical and hemodynamic predictors for successful occlusion of the PDA in infants. This report is to evaluate the outcome of transcatheter occlusion of PDA in symptomatic infants less than 8 kg and to assess predictors of successful occlusion. Retrospective review of catheterization charts and cineangiograms of 42 symptomatic infants who underwent cardiac catheterization for attempted transcatheter occlusion of their PDA was conducted. The hemodynamic and angiographic data evaluated included the length/diameter (L/D) ratio, defined as the length divided by the narrowest diameter of the ductus arteriosus, and preocclusion pulmonary artery pressures. Thirty-one out of 42 patients (74%) had successful occlusion. Twenty-nine out of 42 infants had an L/D ratio > 3. Of these, 26 (90%) had successful occlusion of their PDA. Thirteen out of 42 patients had an L/D ratio < or = 3. Of these, 8 (62%) had unsuccessful occlusion. Complications encountered were transient loss of femoral arterial pulse (n = 6), coil embolization (n = 5), hemolysis (n = 2), and mild left pulmonary artery obstruction (n = 2). No permanent loss of femoral arterial pulse was noted. These complications resulted in no mortality and minimal morbidity. The L/D ratio was the strongest predictor of successful outcome, with an L/D ratio greater than 3.0 being more amenable to transcatheter occlusion (odds ratio of 4.6). Other predictors for success included lower preocclusion systolic, diastolic, and mean pulmonary artery pressure and smaller ductal diameter. Our conclusion was that infants less than 8 kg with an L/D ratio > 3.0 can safely and successfully undergo transcatheter occlusion of their PDA using transcatheter coils.     

Transcatheter closure of patent ductus arteriosus in children weighing <10 kg with Gianturco coils using the balloon occlusion technique

We evaluated the immediate and intermediate follow-up results of transcatheter closure (TCC) of patent ductus arteriosus (PDA) using Gianturco coils in children weighing <10 kg. The results of PDA ≤2.5 mm (group I, n = 18) and >2.5 mm (group II, n = 16) were compared. Coils were deployed sequentially by transarterial route using a temporary balloon occlusion technique. The immediate clinical success rate in both groups was comparable. There was no significant difference in the number of coils required per patient and in the embolization rate between the two groups. Both groups had comparable occlusion rates at intermediate-term follow-up. At intermediate follow-up, one patient had developed left pulmonary artery stenosis while obstruction of the descending aorta was not seen in any; in 4 children the PDA had recanalized. Spontaneous reocclusion was observed in 3 of the latter at the last follow-up. We conclude that TCC of PDA is feasible and safe in children weighing < 10kg with gratifying intermediate-term results. Cathet. Cardiovasc. Diagn. 44:303–308, 1998. © 1998 Wiley-Liss, Inc.     

Transcatheter embolization of recanalized coronary artery fistula with Nit-Occlud device

Congenital coronary artery fistula is a rare anomaly with varying symptomatology that may be addressed with surgical or interventional closure. Recanalization after complete occlusion of a coronary artery fistula has only been reported after surgical but not after interventional closure. We present a case of coronary artery fistula recanalization after angiographically documented complete transcatheter occlusion with Gianturco coils. The fistula was successfully managed by transcatheter implantation of a Nit-Occlud system, originally designed for interventional closure of patent ductus arteriosus.     

Advantages and disadvantages of coils for transcatheter closure of patent ductus arteriosus

Different coils have been used to close the patient ductus arteriosus (PDA). In small- and moderate-sized PDA, coils are an adequate alternative to surgery and/or to other devices. The aim of the study is to review and discuss the advantages and disadvantages of using coils (excluding PFM coils PFM Medical, Germany) to close PDA. Cambier was the first to successfully close a PDA using a Gianturco coil. To date, thousands of patients worldwide have undergone transcatheter closure of PDA using this or other types of coils. The use of coils is analyzed with regard to costs in comparison with other therapeutic modalities; techniques--anterograde, retrograde approach, selection of coil size--in relation to the size of the PDA and the available sizes of coils; efficacy of the rate of complete occlusion and the need for reocclusion; and safety in relation to embolization rate, other complications including hemolysis, left pulmonary artery LPA stenosis and coarctation. It is concluded that coils are a cheap alternative for the occlusion of PDA in the small-to-moderate PDA. The technique can be learned quite quickly, it has a high rate of complete occlusion, and has an acceptable rate of safety. The disadvantages include a moderate rate of coil embolization and of hemolysis in patients with residual shunt after coil occlusion in large PDAs. When more than one coil is used, the potential for developing LPA stenosis is high.     

Comparison of the one-and-a-half-year results of closure of patent ductus arteriosus by transcatheter coils placement with surgical ligation

Patent ductus arteriosus (PDA) is a common type of congenital cardiovascular lesion. It usually needs surgical ligation in a full-term baby after 1 year of age. Transcatheter implantation of coils was introduced for the closure of small- to moderate-sized PDA in 1992. From November 1995 to November 1998, the authors closed the PDA in 153 patients by transcatheter implantation of coils and by surgical ligation in 10 patients. One hundred fourteen of them were studied for more than 1(1/2) years. The regular follow-up studies, including physical examination; electrocardiography; and pulsed, continuous-wave, and color Doppler flow mapping, were performed on day one and day 2, and 1 week, 1 month, 3 months, 6 months, and 1 year after the procedure. The results of the closure of PDA by surgical ligation or coil placement were compared and analyzed in all the patients.     

Successful transcatheter closure of a patent ductus arteriosus: using two Gianturco coils in a 41-year-old woman. A case report.

Patent ductus arteriosus (PDA) is a form of congenital heart disease uncommonly diagnosed in adult patients. Transcatheter closure of PDA has been widely used in children. However, the experience is limited in adults especially with use of Gianturco coils. The authors describe a case of successful transcatheter closure of a PDA, incidentally diagnosed in a 41-year-old woman, by successively deploying two coils by a transarterial approach. No residual shunting was seen angiographically after the procedure. A literature review of similar procedures in adult patients is discussed.     

A Floating Thrombus After Retrograde Gianturco Coil Embolization of a Patent Ductus Arteriosus in an Adult—Detection by Transesophageal Echocardiography

The occlusion of patent ductus arteriosus (PDA) by Gianturco coils has been performed in a growing number of patients since its introduction at the beginning of this decade. The procedure is considered to be effective and safe. Yet embolization of the coil into the pulmonary artery system and residual shunting are typical complications. In some cases a coil loop may protrude into the aortic or pulmonary artery lumen and thus may result in flow disturbances. We report a case of thrombus formation on an intraaortic coil loop after retrograde embolization of a PDA in an adult.     

Transcatheter closure of large patent ductus arteriosus (> or = 4 mm) with multiple Gianturco coils: immediate and mid-term results.

OBJECTIVE: To assess the immediate and mid-term results of transcatheter closure of patent ductus arteriosus (PDA) > or = 4 mm with multiple Gianturco coils. (Transcatheter closure of large PDAs using the Rashkind occluder or the buttoned device is associated with a 7-38% incidence of residual shunt.) METHODS: 19 patients (7 male, 12 female) underwent an attempt at anterograde transcatheter closure with multiple Gianturco coils of a large PDA at a median age of 3.8 yr (range 2 weeks-34 yr) and median weight of 14 kg (range 2.3-80 kg). RESULTS: The median PDA diameter at the narrowest segment was 4.3 mm (range 4-7 mm) and the mean (SD) Qp/Qs was 1.9 (0.8). Each patient had left atrial and left ventricular volume overload. A 4F catheter was used to deliver the coils in all patients. There was immediate and complete closure in 16/18; one patient had residual shunt that was closed at a second procedure and the other had spontaneous disappearance of the residual shunt at the six week visit. A short ductus (angiographic type B) in one patient could not be closed. The median number of coils placed at the first attempt to close the ductus was 4 (range 2-6 coils) and the median fluoroscopy time was 40 minutes (range 13-152 minutes). Mild left pulmonary artery stenosis occurred in the two smallest patients. Coil migration to the lung occurred in 3 patients with retrieval of coils in two patients. All procedures but one were done on an outpatient basis. At a median follow up of 1.6 yr (range 2 weeks-2.2 yr) all patients had complete closure with no new complications. CONCLUSIONS: Anterograde transcatheter closure with multiple Gianturco coils is an effective treatment for most patients with large PDA of diameters up to 7 mm. This technique can be performed in small infants on an outpatient basis without the need for general endotracheal anaesthesia.     

Percutaneous treatment of multiple heart defects

We describe our experience in 6 cases with multiple congenital heart defects treated by percutaneous intervention. Their age ranged from 2.3 to 10 years (mean 6.1), with follow-up from 1 to 84 months (mean 28.8). Two cases had coarctation of the aorta (AC) and persistent ductus arteriosus (PDA). Two patients had pulmonary valve stenosis (PVS) and PDA, one case with aortic stenosis (AE) and PDA and one case with AC, mitral stenosis and subaortic stenosis (Shone's Syndrome). Ductus arteriosus was occluded in all patients with Gianturco coils or Rashkind occluder. The valvular gradient post balloon decreased in cases with AC from 46 to 9 mmHg, with PVS from 110 to 10 mmHg and with AE from 40 to 14 mmHg. In a 8 year old boy with Shone's syndrome, we performed angioplasty of aortic coarctation, mitral valvuloplasty with Inoue catheter. He was referred to surgery for subaortic repair stenosis. All are asymptomatic at follow-up. In conclusion; percutaneous intervention is possible in patients with multiple congenital heart defects.     

Bioptome-assisted simultaneous delivery of multiple coils for occlusion of the large patent ductus arteriosus.

We describe a novel method that allows bioptome-assisted delivery of multiple Gianturco coils simultaneously for occlusion of the large patent ductus arteriosus (PDA). Two or more coils were intertwined at one end and held by a bioptome (5.2 Fr) and pulled into a short introducer. The coils were then deployed in the PDA via a long sheath (7-11 Fr) previously placed across the duct via the femoral vein. Twelve patients (6 months to 64 years; median, 10.5 years) with large PDAs (4.7 +/- 1.3 mm; range, 3.1-8.4 mm; PA mean pressure, 40 +/- 17 mm Hg; pulse pressure 63 +/- 18 mm Hg) underwent bioptome-assisted occlusion with multiple coils at our institutions. The procedure was uneventful in nine patients (fluoroscopy time, 6-23 min) and prolonged in three patients (fluoroscopy time, 26, 72, and 120 min) because of dislodgment of the coil mass and embolization of an additional coil. Successful coil deployment was feasible in all patients. Three patients required repeat coil deployment for flow elimination (hemolysis occurred in two). Flow elimination was demonstrated on the last follow-up evaluation in all except two patients. One infant has developed significant left pulmonary artery stenosis. Bioptome-assisted PDA occlusion using multiple coils delivered simultaneously may be a promising alternative to devices for transcatheter closure of large PDAs. Cathet Cardiovasc Intervent 2001;54:95-100.     

Percutaneous closure of patent ductus arteriosus using special screwing detachable coils

Jackson screwing detachable coils, developed for arterial and venous embolization, have been successfully employed recently for the percutaneous occlusion of patent ductus arteriosus (PDA). Special screwing detachable coils were designed for closure of the PDA, and the experience gained by their use is described in this report. Occlusion was attempted in 29 patients with a minimal ductal diameter of 0.9–4.2 mm. Coils were successfully placed in all 29 patients. One coil, which embolized 10 min after detachment, was retrieved. In 26 patients (89%), complete closure was achieved. Only 35 coils were placed in 29 patients. Residual shunts in three patients are minimal, detectable only on color-flow mapping. Screwing detachable coils for closure of PDA are safe and effective for occlusion of PDA with a minimal diameter <4.2 mm. Embolization of the coil is very rare. A high closure rate is achieved with a low number of placed coils. Cathet. Cardiovasc. Diagn. 41:386–391, 1997. © 1997 Wiley-Liss, Inc.     

Five-loop coil occlusion of patent ductus arteriosus prevents recurrence of shunt at follow-up.

Recent reports suggest reopening of the patent ductus arteriosus (PDA) after complete occlusion with three-loop Gianturco coils. We hypothesize that five-loop coils may produce a larger thrombus than three-loop coils, which will result in no or less probability of recanalization of PDA during follow-up. This study is designed to test this hypothesis. Follow-up echocardiographic and Doppler data of 30 patients who underwent five-loop coil occlusion of small to medium-sized PDA during a 33-month period ending December 1998 were examined. Thirty patients had no residual shunt on echo Doppler study on the day following the procedure and were followed for 6 to 30 months (median, 12) after coil implantation. At the last follow-up study, none of the patients had a residual shunt and left atrial size decreased. Careful pulsed, continuous wave, and color Doppler interrogation of left/main pulmonary artery junction and proximal descending aorta did not reveal any evidence for obstruction. The follow-up data suggest that complete occlusion of small- to medium-sized PDAs is feasible with five-loop coils without evidence for recanalization at a mean follow-up of 12 months. Much longer (2 to 5 years) follow-up data may be necessary to confirm these observations. We speculate that a greater degree of thrombosis is produced within the ductus by the five-loop coils, which in turn may be responsible for lack of shunt recurrence. We recommend use of five-loop instead of three-loop coils for transcatheter occlusion of small- to medium-sized PDAs.