Atrial Septal Occluder Device Embolization is Avoidable

The first ASD closure device was implanted by Babic et al. in 1990.[1] Percutaneous closure of Atrial Septal Defect (ASD) is now commonly performed for ostium secundum type defects where there are no risk factors for failure of device closure, such as inadequacy of ASD rims and a maximum diameter of ASD beyond 34 mm. Multiple ASD occluder device systems have been developed since. The ASD occluder devices currently preferred are the Amplatzer, Gore, Occlutech Figulla Flex II, CardioSEAL, Helex Septal, and Nit-Occlud PDA-R. The choice of the occluder device depends on various factors, including the anatomy, size, and location of the defect and the treating physician’s preference.

Careful echocardiographic evaluation of the adequacy of ASD rims, especially the inferior rim, is pertinent while selecting patients for percutaneous device closure. In addition, associated pulmonary hypertension, multiple ASDs, aneurysmal or floppy interatrial septum, and other ASDs like the Ostium Primum ASD or Sinus venosus type ASD or the presence of anomalous pulmonary venous drainage preclude the percutaneous ASD device closure with an occluder device.

In this journal issue, Garre S et al. present a retrospective analysis of 30 ASD occluder device dislodgement events out of the 2237 ASD device closures performed at a tertiary care center over 12 years.[2] As a standard institutional protocol, the occluding device placement was conducted with intra-procedure echocardiographic guidance. The authors report that almost half of these patients had preoperative trans-thoracic echocardiography (TTE) findings suggesting an unsuitable inter-atrial septal morphology. The report emphasizes the need for careful preoperative assessment before pushing the limits of reliable device stability and also merits emphasis on careful re-evaluation by echocardiography under general anesthesia before femoral vessel puncture for the intervention.

Garre S et al. report more embolizations using the Blockaid and the Cocoon devices in their series.[2] Both these devices aren’t preferred today. The detailed temporal profile of the device dislodgement after placement, the cardiac chamber to which the device embolized, along with the clinical symptoms leading to detection and significant perioperative complications encountered provide an opportunity to understand these events better. The report does not mention the year-wise analysis of the number of events of device embolization. The pre-procedure TTE echocardiographic assessments could have improved during the reported analysis timeline, and the preference for the type of occluder device changed, leading to better outcomes.

We had reported the clinical profile of a case of ASD occluder device embolization to the main pulmonary artery and its implications on perioperative management in an early publication on embolization of the device [before the use of trans-esophageal echocardiography (TEE), for such placements, became routine].[3] The accompanying commentary emphasized the indications for anesthetic care and the various aspects related to assessment, like ‘sizing’ of the ASD, before transcatheter closure of an ASD using an occluder device. The report also elucidated the pre-anesthetic assessment and anesthetic considerations, including the relevant pathophysiology.

ASD device closure is assigned a risk category 2 as per the Catheterization for Congenital Heart Disease Adjustment for Risk Method (CHARM) score.[4] Some potential anesthetic implications of device embolization are hemodynamic compromise/collapse, thromboembolism (especially when it gets lodged on the atrial wall), infection, and emergency airway management. The odds of suffering a high-risk adverse event in patients with Ostium secundum type ASD are, however, minimal.

Garre S et al. report one fatal outcome among a composite of 2237 attempted cases of ASD occluder device closure.[2] Air embolism from the right atrium, subsequent hemodynamic complications, and brain stem hemorrhage probably lead to a fatal outcome in one patient. A total circulatory arrest had to be instituted in another patient to retrieve the device in the case series successfully. More than half (17 out of 30) patients with ASD occluder device embolization, in this series, were referred for surgical retrieval. The report does not mention the clinical course of the remaining patients (13 out of 30).

More than 80% of patients with ASD have an ostium secundum defect and occluder device placement avoids surgery with cardiopulmonary bypass. Reports describing such serious adverse events need not deter nascent cardiac teams from developing cardiac intervention programs.[5] There are no reports of a cost analysis of the embolization of ASD devices in the existing literature. The cost-benefit of transcatheter device closure of ASD, compared to surgical closure, appears unmatched despite the device cost and the necessary cardiac catheterization lab setup. This is intuitive from the benefits of avoiding the risks associated with surgery under cardiopulmonary bypass and shorter hospital stays.

Intraoperative TEE guidance during cardiac interventions is essential. Careful preoperative assessment of the risk factors for device embolization, mainly by echocardiographic criteria, is the central message in all reports on ASD device embolization. Echocardiography has evolved from a pre-procedure screening method to an effective tool for intra-procedure guidance during device placement. The 2D guidance provided by fluoroscopy can be augmented by color doppler echocardiography (TTE or TEE) to ascertain the appropriate device placement and fit on all rims of the ASD. 3D echocardiography has unique capabilities of pre-procedure anatomical assessment along with real-time guidance to device placement and its use is increasing.

With aggressive cardiac interventions constantly pushing the envelope of conventional indications, there is an inescapable role of intra-procedure echocardiography by a trained cardiac anesthesiologist. Careful pre-procedure TEE assessment under general anesthesia, before femoral vessel puncture, and real-time procedural guidance during device placement will reduce the incidence of device embolization.