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although this method of therapy may be more expensive , it is preferable over surgery due to less traumatic burden and better cosmetic results [ 2 , 3 ] .
in addition to fluoroscopy , an echocardiographic imaging modality is necessary to guide the interventionist during this procedure .
transesophageal echocardiography ( tee ) or intracardiac echocardiography ( ice ) are standard methods for this purpose . however , both methods are relatively inconvenient since they either require general anesthesia ( tee ) or high cost catheters and special training .
many patients or pediatric cardiology centers can not afford high expenses of purchasing and maintaining these equipments . on the other hand ,
there is little evidence in the literature about asd closure under tte guidance [ 47 ] . in this retrospective study , we report the results of asd device closures in 32 consecutive patients less than 40 kg under tte guidance .

 subjects : from october 2006 to december 2010 , transcatheter asd closure was attempted in 37 patients with secundum asd at an academic hospital . of those ,
inclusion criteria were the existence of an asd with significant shunt which was suitable for device closure ( see the procedure section ) .
median age at the procedure was 5 years ( range 214 ) , and median weight 15 kg ( range 940 ) . mean pulmonary artery pressure ( mpap ) was 17.64.1 mmhg , and pulmonary to systemic shunt 2.20.6 to one .
median defect size was 14 mm ( range 628 ) , stretched defect size 16 mm ( range 8.530 ) , and device size 16 mm ( range 930 ) . 

procedure : indication of asd closure was set when pulmonary flow was at least 1.5 times higher than systemic flow .
defect diameters were measured in subcostal sagittal and coronal , apical four- and five - chamber , and short - axis views . the defect rims to aorta , mitral and tricuspid valves , superior and inferior venae cavae ( svc and ivc ) , and right pulmonary veins were determined in the same views .
a minimum of 5 mm for septal occluders with exemption of aortic rim was required for device closure .
total septal dimensions were also measured and if they were not at least 2 mm larger than device discs , device closure was not attempted .
any concomitant cardiovascular abnormality was searched to repair if possible by transcatheter techniques or to schedule for surgery .
three patients had severe pulmonary stenosis which was treated simultaneously by balloon valvoplasty . after obtaining informed consent ,
after complete right heart catheterism , a pulmonary angiography was done at anteroposterior view to exclude any anomalous pulmonary venous drainage . at this stage ,
, asd stretched diameter was determined using sizing balloon catheters ( aga medical corporation , usa ) in all patients except two . in these two smallest most recent patients , we preferred to use a device at least 15% larger than the defect size without balloon sizing to decrease the risk of defect stretching in small children .
of 30 implanted occluders , 16 were atrial septal occluder ( lifetech scientific , pr china ) , 6 amplatzer septal occluder ( aga medical corporation , usa ) and 8 cardio - o - fix asd occluder ( starways medical technologies , pr china ) . to order an appropriate device size
, we added 15% to the largest measured defect diameter on pre - procedure echocardiogram .
however , during the procedure we changed the device size to a larger one only if the stretched diameter was more than 1 mm greater than the pre - selected device size .
we selected a larger device 2 mm of stretched diameter which needed repeated catheterization in one patient due to device unavailability .
transthoracic real - time echocardiography was done during several steps of the procedure using either an esaote mylab 50cv or toshiba ui th-370a echocardiographs .
first , stretched defect size was measured when shunting across the defect was eliminated on subcostal view during slow balloon inflation ( static sizing , stop - flow diameter ) [ 9 , 10 ] .
second , tte was used to confirm correct left atrial disc position on the defect ( subcostal view ) . then aortic , mitral , pulmonary , ivc , svc , right pulmonary venous , and coronary sinus flows ; position of the device ; and the presence of any residual shunt or missed additional defects were investigated by tte ( fig .
fluoroscopy was done between these steps to deploy the discs and to doubly check the position of the device .
but we tried to limit these occasions because of x - ray hazards to the echocardiographer ( fig .
care was taken to prevent contamination of the catheter introduction area while performing echocardiography and changing the position of the camera .
echocardiographic image of the atria , interatrial septum and septal occluder ( white arrow ) during catheterization , showing optimal position of the occluder .
one of the infrequent situations where fluoroscopy and echocardiography were used simultaneously . 
 follow up :
eight patients did not return later than the first follow up visit ( one month after the procedure ) .
aspirin was administered to all patients for 6 months ( 35 mg / kg daily ) .
physical examination , electrocardiography , chest radiography and tte were performed at each scheduled follow up visit
. 
 statistical analysis : descriptive statistics such as mean , median , standard deviation , and frequency were calculated for each demographic and clinical characteristic whenever appropriate .

 immediate : of 32 attempted asd transcatheter closures , the procedure was successful in 30 ( 94% ) .
eight of 30 ratios ( 27% ) were less than 1.125 and 3 ( 10% ) were more than 1.33 .
in the first failed patient ( 2.5 years of age , 12 kg ) , the measured defect size by echo was 10 mm . during the procedure
we first tried to deploy a 12 mm metallic device and then a 14 mm one , but both trials were unsuccessful .
as patient 's total septal diameter ( around 30 mm ) was not large enough to accept a bigger device , we ended device closure . in the second failed patient ( 8.5 years of age , 18 kg ) , the unstretched and stretched defect diameters were 26 and 29 mm , respectively .
we tried to implant a 30 mm device but we could not position it on the septum .
differentiating between svc flow disturbance over sizing balloon and small residual shunts was difficult in some patients . 

. however , this modality has some disadvantages when used for children . not only the purchase but also
tee in children requires general anesthesia due to patient intolerance which adds to the cost and complexity of the equipments .
the main disadvantage of ice is its cost . in the past , the need for at least an 11 fr sheath for the 10.5 fr acunav catheter ( acuson corporation , simens medical , usa ) was another drawback .
although both tee and ice provide constant and high quality images during asd device closure , their cost disadvantages make them unaffordable for the hospitals and patients in developing world .
second , there are a risk of infection due to the proximity of catheterism site and subcostal region .
third , simultaneous use of fluoroscopy and echocardio - graphy can expose the echocardiographer to a large radiation dose .
although the image quality of tte is suboptimal , we showed that it could be enough for successful device implantation .
underestimation of the defect size , balloon overstretching , small size of the patient , and use of tte may lead to the procedural failure in the first patient .
our limited experience in closure of large defects , relatively small size of the patient and tte guidance were possible causes for the failure in the second case .
3 ) . left atrial disc of large metallic occluders often prolapse to the ra due to their perpendicular positioning .
several techniques or special equipments were suggested to prevent this problem during large asd ( defect size more than 25 mm ) closure [ 1517 ] .
we used a straight long sheath without any curve at its end ( william cook europe , denmark ) instead of the traditional curved ones to deliver a 30-mm amplatzer septal occluder in this patient .
successful implantation of a 30-mm amplatzer septal occluder using a long sheath with straight tip . left , forwarding the device in the straight long sheath ; middle , implanted device before release ; right , final position of the device great care was paid to antiseptic management , especially while changing camera position .
the echocardiographer tried not to touch the sterilized catheterization area either by hand or echocardiography probe .
the interventionist should accept the problem of frequent camera position changes and possible resultant extra time .
the echocardiographist also should accept the need for simultaneous echocardiography and fluoroscopy in rare occasions ( fig .
an unknown number of asd closures in the report of fischer et al were done under tte guidance .
zaquot et al used tte during asd closure in 2 patients due to surgically repaired transesophageal fistula in one and technical failure of tee in the other .
they were successful in 57 procedures but failed in 6 including one device dislodgement and one embolization .
three - dimensional echocardiography is increasingly recognized as a useful tool for delineating the shape of the asd and number of the defects before asd closure .
in addition , it can be additive or even superior to other modalities in guiding the procedure [ 19 , 20 ] .
all sizes of these devices can not be available in our catheterization laboratory at the same time .
therefore , we developed a protocol to select device size and purchase it before the procedure .
we changed our selected size after balloon sizing only in 6 out of 30 patients .
our sizing protocol complies with the general trend to implant smaller devices [ 9 , 10 ] .
we encountered no major complication from device over- ( erosion , pericardial effusion ) or undersizing ( device embolization ) , although more than one third of device / defect ratios were out of the safe zone ( 1.1251.333 ) proposed by rastogi et al .
limitations of our study were use of devices from different companies , unavailability of all device sizes , and lack of a control group .
we conclude that asd device closure can be safely done under tte where more sophisticated echocardiographic modalities ( tee , ice ) are not available or affordable by the hospital or patient .
however , for patients with relatively large defects we recommend either using tee or ice .
objectiveatrial septal defect ( asd ) device closure is routinely done under the guide of transesophageal or intracardiac echocardiography which are expensive techniques and not easily affordable in developing countries.methodsusing metallic devices , we attempted 32 asd device closures under transthoracic echocardiography.findingsof those , 30 procedures were successful ( 94 % ) . in two patients with relatively large asd we encountered difficulty in positioning the device . 
 these patients were referred for surgical closure.conclusionasd device closure can be carried out successfully in most patients under transthoracic echocardiography in situations where transesophageal or intravenous echocardiographies are not available or affordable .