Background
Intracardiac echocardiography (ICE) is commonly used during interventional cardiac catheterization in adults, but data regarding the use of ICE in children are limited. There are no data available comparing the effectiveness of preprocedural transthoracic echocardiography (TTE) with that of intraprocedural ICE in predicting atrial septal defect (ASD) size and rim adequacy for percutaneous closure in a pediatric population. The objectives of this study were to describe the investigators’ experience using ICE in pediatric and adolescent patients and to compare the effectiveness of preprocedural TTE with that of ICE in predicting ASD size and rim adequacy for percutaneous closure.
Methods
In this retrospective study, all cases in which ICE was used during ASD or patent foramen ovale closure in patients ≤21 years of age at a single institution from January 2002 through October 2013 were reviewed. All studies were performed using the Acuson AcuNav ICE system.
Results
One hundred fifteen patients (65 female; mean age, 12 ± 6 years; range, 10 months to 21 years) were included. All intracardiac echocardiographic studies were performed by the interventional cardiologist performing the catheterization. ICE was used to facilitate ASD closure in 92 patients (81%) and patent foramen ovale closure in 23 (19%). Thirty-eight patients (34%) underwent cardiac catheterization and ICE without general anesthesia. ICE was correlated highly with preprocedural TTE in predicting ASD size ( r 2 = 0.76, P < .0001). In nine of 92 patients (9.8%) with ASDs, ICE identified deficient septal rims ( n = 8) or complex or multiple ASDs ( n = 1) that necessitated surgical closure. There were no major complications.
Conclusions
ICE can be performed safely and effectively in a large cohort of children and adolescents undergoing percutaneous device closure. ICE may obviate the need for general anesthesia in some patients and is a reasonable alternative to transesophageal echocardiography for this catheter-based procedure in children. ASD measurements with ICE correlate well with preprocedural measurements on TTE; however, ICE more accurately identifies the absence or deficiency of critical septal rims before device closure.
Intracardiac echocardiography (ICE) is recognized as a valuable imaging option during adult interventional cardiac procedures. ICE allows echocardiographic imaging from within the heart during catheter-based procedures, avoiding the need for endotracheal intubation and general anesthesia, which often accompanies the use of transesophageal echocardiography (TEE). Furthermore, ICE has been shown to provide comparable imaging compared with TEE and transthoracic echocardiography (TTE).
In 2004, our institution first reported our experience using ICE in adults during transcatheter atrial septal defect (ASD) or patent foramen ovale (PFO) closure. Since that time, ICE has become more widely used, particularly during ASD or PFO closure among adult patients. Although the use of ICE among adults has been well described, data regarding the use of ICE in pediatric patients are limited. Additionally, little is known regarding the effectiveness of preprocedural TTE compared with ICE in accurately describing ASD size and rim adequacy for percutaneous closure in this population.
ICE use in the pediatric population has become the standard of care at our institution for echocardiographic imaging during transcatheter closure of ASDs and PFOs. As a result, we rarely perform TEE on children in the cardiac catheterization laboratory. Herein, we describe our experience with the use of ICE and its comparison with preprocedural TTE in pediatric and adolescent patients undergoing catheterization for closure of ASDs or PFOs.
Methods
Review
In this institutional review board–approved retrospective study, we reviewed all cases of ICE use during percutaneous ASD or PFO device closure at our institution between January 2002 and October 2013 in patients ≤21 years of age. From the available medical records, we abstracted demographic data, type of atrial shunt (ASD vs PFO), procedure duration, fluoroscopy time, and any procedural complications attributable to ICE use. We defined ICE-related complications as any of the following: groin hematoma, arrhythmia, cardiac perforation, entrapment of device or sheath, air embolism, or vascular damage that could be attributed to ICE catheter manipulation. Groin hematoma was classified as a minor complication if it resolved without sequelae. Procedure duration was defined as the time from initial sheath placement to sheath removal (“sheath time”).
Preprocedural Imaging
Because of the nature of our referral practice, preprocedural transthoracic echocardiographic images had been obtained at variable time periods before the procedure date. Transthoracic echocardiographic images were obtained in the standard imaging planes, as previously described. Description of the locations and number of defects and the adequacy of septal rims for device closure were obtained from the TTE report. In patients with single ASDs, defect dimensions were remeasured from available preprocedural transthoracic echocardiographic images by one investigator (N.W.T.), who was blinded to intracardiac echocardiographic findings and procedure outcomes. The largest defect dimension was recorded. In the case of PFO, any anatomic description of the foramen ovale (e.g., “tunnel-like” configuration) was recorded.
ICE
All studies were performed using the Acuson AcuNav ultrasound catheter system linked to a Sequoia ultrasound-imaging platform (Acuson Corporation, Mountain View, CA). Femoral venous access (8- or 9-Fr sheath for the 8-Fr AcuNav catheter; 10- or 11-Fr sheath for the 10-Fr AcuNav catheter) was obtained after administration of local anesthetic. General anesthesia was used for the youngest patients, as well as for selected older patients who had significant anxiety related to the procedure. All other patients were managed with conscious sedation. All decisions regarding type of sedation or anesthesia were made by the attending anesthesia staff in consultation with the cardiologist performing the procedure. Sedation and anesthesia administration was managed by a certified registered nurse anesthetist and supervised by an anesthesiologist. All patients received intravenous heparin (50–100 IU/kg) during the procedure. Additional heparin was administered as needed throughout the procedure to maintain adequate anticoagulation at the discretion of the performing cardiologist.
Under fluoroscopic guidance, the intracardiac echocardiographic catheter was advanced from the femoral vein into the right atrium. Infrequently, the catheter was also advanced into the superior vena cava to obtain specific focused images. Complete intracardiac echocardiographic evaluation of the left and right heart was performed in most patients, as previously described.
Before sizing of the defect, ICE was performed to evaluate for multiple defects, rim deficiencies, and anomalous pulmonary veins. Adequate atrial septal rims have been defined for use of the Amplatzer Septal Occluder device (St Jude Medical, Inc, St Paul, MN) as ≥5 mm to the coronary sinus, atrioventricular valves, and right upper pulmonary vein ( Figure 1 ). In addition, the manufacturer warns that patients with deficient (<5 mm) anterior-superior (retroaortic) rims may be at increased risk for device erosion into the aortic root; however, deficiency of this rim is not an absolute contraindication for use of the Amplatzer Septal Occluder device ( Figure 2 ). Specific septal dimension requirements have not been established for use of the Gore HELEX septal occluder device (Gore Medical, Flagstaff, AZ). Instead, the manufacturer states that the device should not disrupt surrounding cardiovascular structures and that there should be “adequate” septal rims to secure the device along ≥75% of the circumference of the defect.
When sizing the defect, both static and balloon-sized dimensions were evaluated. For balloon sizing the defect, both ICE ( Figure 3 ) and fluoroscopic measurements were performed. Color-flow Doppler imaging was used during balloon inflation to demonstrate complete defect occlusion and to expose any additional, smaller defects. During device placement, ICE was used to ensure proper device positioning, as previously described by Earing et al . All available intracardiac echocardiographic images were retrospectively reviewed by one author (N.W.T.) blinded to the preprocedural findings of TTE. The largest static (non-balloon-sized) defect dimension was recorded.
Comparison of TTE and ICE
For patients with single ASDs, transthoracic and intracardiac echocardiographic images were independently reviewed as described above, and the largest defect dimension was recorded for both imaging modalities. If either transthoracic or intracardiac echocardiographic images were not available for review, the largest dimension documented in the formal echocardiography report was recorded and included in analysis. Patients were excluded from the comparison of TTE and ICE comparison if transthoracic or intracardiac echocardiographic images were unavailable for review and no defect dimension was documented in the echocardiography report. Patients found to have multiple defects were also excluded.
Statistical Analyses
All continuous variables are reported as mean ± SD, median, and range. Categorical variables were compared by using χ 2 tests. Preprocedural ASD dimension on TTE was compared with dimension on ICE using a two-sided paired t test.
Results
Cohort Demographics
Overall, 115 patients (65 female; mean age, 12 ± 6 years; range, 10 months to 21 years) underwent ASD ( n = 92 [81%]) or PFO ( n = 23 [19%]) closure with guidance by ICE. An additional 11 patients underwent ASD closure without guidance by ICE: nine with transesophageal guidance and two with transthoracic guidance. These patients were not included in our ICE cohort. The mean weight of the cohort was 45 ± 25 kg (range, 8.3—121 kg). Fifteen patients weighed ≤15 kg.( Table 1 ) All patients had previously undergone preprocedural TTE on average 45 days before catheterization (range, 1–377 days). Only 16 patients had undergone preprocedural TEE (12 with PFOs, four with ASDs); 11 were performed at our institution (seven with PFOs, four with ASDs) and five at an outside referring institution (all with PFOs).
| Variable | Value |
|---|---|
| Total cohort | 115 (100%) |
| ASD/PFO (% ASD) | 92/23 (81%) |
| Age (y) | 12 ± 6 (0.8–21) |
| ≤6 | 37 (32%) |
| 7–12 | 19 (16%) |
| 13–18 | 35 (30%) |
| 19–21 | 26 (22%) |
| Weight (kg) | 45 ± 25 (8.3–121) |
| ≤15 | 15 (13%) |
| Male/female (% male) | 50/65 (43%) |
| 8-Fr catheter/10-Fr catheter (% 8 Fr) | 61/54 (53%) |
| Procedure time (min) | 76 ± 26 (18–158) |
| Fluoroscopy time (min) | 21 ± 10 (2–85) |
| General anesthesia | 77 (66%) |
| Significant complications | 0 (0%) |
In two patients, ICE documented the absence of atrial-level shunting, and no interventions were performed. These patients were not included in our cohort. One of these patients reportedly had mild right ventricular enlargement with exercise intolerance with multiple small fenestrations of his atrial septum demonstrated on TTE. At the time of catheterization, however, no shunt was identified. The second patient had a history of ischemic stroke. Transthoracic color-flow imaging suggested an atrial-level shunt that was not identified by ICE at the time of catheterization. These patients did not undergo TEE before catheterization.
Procedure Details
An 8-Fr intracardiac echocardiographic catheter was used in 53% of cases, with a 10-Fr catheter used in the remainder. The size of the catheter used was at the discretion of the interventionalist. In general, 8-Fr catheters were used in younger (mean age, 8.7 ± 5.5 vs 15 ± 4 years; P < .0001) and smaller (mean weight, 30 ± 20 vs 61 ± 17.5 kg; P < .0001) patients.
General anesthesia was used in 77 of 115 patients (66%) because either young age ( n = 55, age ≤ 13 years) or patient anxiety ( n = 22). In all cases, the interventional cardiologist performed both the catheterization and intracardiac echocardiographic image acquisition and interpretation without assistance from a sonographer or an echocardiographer. The mean time from sheath insertion to sheath removal was 76 ± 26 min. Mean fluoroscopy time was 21 ± 10 min.
No patient in this series developed atrial arrhythmias as a complication of ICE use. One patient (0.9%), aged 32 years, had a vascular access–related complication with bilateral groin hematomas that resolved without sequelae. A 10-Fr intracardiac echocardiographic catheter was used in this patient on the left side only. There were no complications resulting in blood transfusion or resuscitative interventions during any procedure, and no other significant complications occurred.
Device closure was successful in all patients with PFOs ( n = 23). In two patients, ICE identified “long-tunnel” PFO morphology ( Figure 4 ), which complicated traditional device closure. One of these patients underwent preprocedural TEE, but no mention was made of the tunnel morphology. In the other patient, preprocedural TTE was interpreted as a small ASD with possible fenestrations. This patient did not undergo preprocedural TEE. In these two patients, ICE facilitated transseptal puncture for device placement across the primum septum.
