Page 20 - Journal of Structural Heart Disease Volume 4, Issue 3

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Original Scienti c Article
It has been argued that the relation between the device left atrial disc volume and the left atrial vol- ume might be a more sensitive predictor [20]. In this study, we used the device diameter in relation to left atrial dimensions. The volume of the left atrial disc is the result of its diameter and thickness. The thickness of the disc is a constant and the changes in its vol- ume is the result of the changes in its diameter which constantly related to device waist diameter. However, volumes relations could be a more useful predictor.
In this study, we de ned procedure prolongation as deployment time beyond ten minutes. This cut- o time limit was selected depending on our expe- rience, where the time from deployment to release of the device was six to eight minutes in the majority of the cases. Thus, we decide ten minutes would be a rational limit to de ne short and prolonged proce- dure as the operator might consume additional short time. The deployment time could be a ected by re- peated attempts to deploy the device, using di erent deployment methods (balloon-assisted deployment, right pulmonary vein etc.), using more than one de- vice, loss of device memory (Cobra deformity), deliv- ery sheath distortion, and di culty of getting clear TEE images to con rm proper and stable device po- sitioning. All these variables are in uenced by the experience of the operator and the echocardiogra- pher. Skilled operators and experienced echocar- diographers can achieve shorter deployment times. However, the e ect on deployment time due to the operator experience would be relatively same in all procedures. Equipment failure during procedure can also prolong the deployment time however we did not experience such type of di culty in this study.
The study showed that the rim toward superior vena cava as a signi cant predictor for procedure pro- longation. The ROC curve resulted in a cut-o value of the rim < 12 mm. We nd this value is far much longer than what is usually considered to be de cient (i. e. 5 mm) [1]. Such result may need to be studied further.
Device embolization occurred in three patients (3.7%). The rst patient came to the emergency de- partment one week after closure with a complaint of chest pain. The symptoms started on the previous day after jumping on the trampoline. Echocardiog- raphy showed that the device embolized to the left ventricular out ow tract. The embolization was con-
sidered to be due to a relatively small device and the vigorous physical activity which should be avoided at least for three months after the procedure. In the second patient, echocardiography before discharge, next day, revealed that the device embolized to the left atrium. Similarly, in the third patient, chest X-ray before discharge revealed that the device embolized to the descending aorta. Retrospectively, we could assume that embolization could have been avoided by using bigger closure devices to get better device xation and stability; especially in the presence of double septal contour in the two patients and short aortic rim in one.
Three patients who were eventually referred for surgical closure of the defect (two after device em- bolization and one because of device mal-position which was irretrievable due to distorted sheath) and one had device embolization which was retrieved percutaneously. All patients belonged to the pro- longed group and have an SVC rim (8, 9, 9, 11 mm) shorter than the cut-o length (12 mm). This nding may indicate that while the three other variables are only predictors of procedure prolongation, a shorter SVC rim might predict the risk of embolization in ad- dition to procedure prolongation.
Limitations of the study
The major limitations of this study are its retro- spective nature and the relatively small number of patients. An additional limitation is that the results are from a single center experience. The e ect of rim de ciency toward inferior vena cava was not studied as such, as patients with such rim de ciencies were sent to surgery without further attempts at PTCC.
The prolonged procedure group was signi cantly younger than the other group. It also di ered from the other group in other variables that could be used as predictors, but the di erences between the groups were not statistically signi cant, possibly because of the relatively small number of patients.
Conclusions
This study reinforces previously published litera- ture reporting that the percutaneous transcatheter closure of atrial septal defect is riskier and may unex- pectedly convert into a di cult and prolonged pro-
El-Segaier M. et al.
Predictors for Prolonged ASD Closure