TRANSCATHETER PDA CLOSURE USING THE AMPLATZER DUCT OCCLUDER BY: JAMEEL AL-ATA, MD ASSISTANT PROFESSOR and CONSULTANT PEDIATRIC CARDIOLOGIST

INTRO: Transcatheter closure of the small to moderate patent ductus arteriosus utilizing coils is an accepted treatment (…Hijazi, Galal Int card).

Addressing the larger PDA using multiple coils was shown to be feasible, but not without problems (Hizji, > 4mm PDA, Galal Zeitschrift kardiologie).

INTRO: The large PDA remained the domain of surgery for a while. Only recently the Amplatzer duct occlude (ADO) has been introduced as an alternative (Masura) ( Saliba)

Especially in the younger age and weight group there are still relatively few reports describing the experience with this device (Alwi JACC 2001)

The aim of this study: To present our experience with the ADO to close large PDA in a relatively young patients population.

Special attention was taken to focus on the selection of the optimum sized device as well as the problems and complications which can be encountered while using this device.

METHODS: In a clinical study, all 43 patients (29/43 females, 14/43 males) who underwent attempt of transcatheter closure of their patent ductus arteriosus using an Amplatzer duct occlud between July 2001 and October 2003 were reviewed.

Inclusion criteria: All patients who had a PDA, which was judged angiographically to be too large for a single coil implantation ( > 3 mm narrowest diameter) were included in this study.

Exclusion criteria: Patients who underwent transcatheter closure in which coils were utilized. Had other cardiac anomelies.

Clinical Examination and Echocardiographic Evaluation: All patients underwent complete cardiac evaluation; including physical examination, twelve lead ECG, and a radiogram of the chest.

Cont.: Detailed echocardiograms were performed at baseline using Hewlett Packard Sonos 5500.

CONT: The narrowest diameter of the PDA was measured in the ductal view using color Doppler and electronic calipers.

Cont.: Routine M-mode echo tracings were obtained in the parasternal long axis view as recommended by the American Association for ECHO.

Cont.: Follow-up echocardiograms were performed in most before discharge, one month and then 6 months after closing the ductus arteriosus.

Cardiac Catheterization procedure: In all patients signed consent was obtained from their parents. Patients were sedated with ketamine and midazolam during the procedure.

Cont.: None of the patients received general anesthesia or intubation. Heparin in a dose of 100 IU/kg was administered

CONT: Aortograms performed in straight lateral position were reviewed to determine the PDA diameter and the type of the ductus was described according to the classification of Krichenko.

Cont.: The narrowest diameter of the PDA, the aortic diameter of the ampulla, the length of the ampulla and the mid diameter of the ampulla were measured.

CONT.: Amplatzer duct occlud of the PDA was performed through anterograde approach

Study group: The procedure proved successful in 42 patients (97.5%). We used a device of size 6/4 in 21 of the patients (50%), using the 8/6 device in 10 (24%), the 10/8 device in 7 (16.5%), and the 12/10 device in 4 (9.5%) of the patients.

Cont.: In all patients who underwent implantation of devices, cefuroxime (30 mg/kg) was administered intravenously during the procedure. Two more doses were given with the next 24 hours.

Selection criteria of the ADO: The duct occluder is offered in five different sizes. The first number mentioned on the package of the device belongs to the larger diameter of the device, which is 2 mm larger than the smaller diameter given on the package.

Cont.: The larger diameter is usually positioned in the aortic end of the ductul ampulla, while the smaller diameter is positioned at the pulmonary end.

Cont.: In the first two patients, we followed the recommendation suggesting to use a duct occluder in which its smaller diameter (pulmonary end) is 1-2 mm larger than the narrowest diameter of the specific duct.

Cont.: In view of the problems we encountered with positioning of the second device, we tried to put all the measurements of the PDA into consideration, while selecting adequate ADO.

Cont.: In this specific case,though the Recommendation was followed, because of a mismatch between the skirt of the device and aortic end of the duct, the skirt of the device protruded into the descending aorta.

Cont.: We therefore measured the narrowest diameter of the duct, its length, & the largest diameter for the aortic end,

Cont.: Since it has to accommodate the skirt of the device, which is 4 mm larger than the number given for the larger (aortic) end of the ADO.

Cont.: The mid ductul diameter was also measured, so to make sure in case the duct is too long, that the larger part of the ADO will fit.

Results:

Age (years) 3.79 ± 3.82 (0.45 - 13) Sex Weight (kilograms) 29 females, 14 males Weight (kilograms)   11.9 ± 8.91 (4.5 – 44) Height (centimeters) 83.6 ± 21.1 (59 – 154)

Systolic pulmonary arterial pressure (millimeters of mercury) 40 ± 17.8 (17-87)   Systolic aortic pressure  (millimetres of mercury) 88 ± 21.9 (59-115) Ratio of pulmonary to systemic flows 2.43 ± 1.6 (1-7.6) Index of pulmonary arteriolar resistance (Wood units) 3.29 ± 1.91 (0.39-6.5)

Time required for fluoroscopy (minutes) 16.9 ± 7.8 (5.6-36.7) 16.9 ± 7.8 (5.6-36.7)   Overall procedural time 102 ± 31.7 (46-169) Contrast used (milligrams per kilogram) 5.81 ± 4.1 (1.6-17.9) Narrowest diameter of duct (millimetres) 5.18 ± 1.9 (3.4-11.1) Largest diameter at the aortic ampulla 13.6 ± 4.9 (8-21) Diameter at the mid-ampulla 10.2 ± 3.1 (5.9-15) Total length of the duct 12.9 ± 5.1 (6-21.8)

Cont.: All patients were done as a day case. None had to be admitted over night.

Rate of occlusion: Immediate occlusion, confirmed angiographically, was achieved in 25 (60%) patients. In another 8 (19%), complete occlusion occurred some hours after the procedure, as confirmed by echocardiography. In 33 (79%) of the patients, therefore, complete occlusion was achieved on the day of the procedure.

At a further follow-up, of between one week and 6 months, complete occlusion had occurred in 6 more patients. At that time, 2 patients had trivial residual shunting, while one had a significant residual leak.

Issues pertinent to Procedure: Mean number of angiographies to visualize the PDA before implantation was 1.8 injection (range 1-7).

PROBLEMS & COMPLICATIONS There was no device embolization. There was no loss of pulse. There was no mortality.

Cont.: Waist of coils 3 coils in one patient Waiste of Amplatzer in two patients Pull through of device in three patients

Cont.: Kinking of sheath and inability to retrieve a too large device. Excessive bleeding needing transfusion in one. Difficulty in visualizing the large PDA.

Conclusions: Transcatheter occlusion of PDA by the ADO has a high complete occlusion rate and is effective in PDA up to a narrowest diameter of 10 mm and probably larger PDAs.

Cont.: Especially in the young age group, problems & complication rate of 30% can be encountered in the learning phase. The ADO diameter should not exceed the largest ampulla diameter of the PDA in order to avoid descending aortic obstruction.