Clinical & Experimental Cardiology
Open Access

The Occluder Device for Transcatheter Patent Foramen Ovale (PFO) Closure with Reserved Interatrial Septal Puncture Area

Haibin Jiang^{* *}Correspondence: Haibin Jiang, Department of Cardiology, Jiangnan University Medical Center, Wuxi, China, Email:

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Introduction

Patients with Patent Foramen Ovale (PFO), a kind of atrial septal abnormality, do not have a fully closed foramen ovale at birth. PFO is 20%-30% common in the general population, whereas it is 27% common in autopsy examinations. In nearly 43% of young, healthy persons, the highest documented prevalence of PFO to date was found in the biggest Transcranial Doppler (TCD) epidemiologic study conducted in the Greek population. Moreover, there are significant differences in PFO rates discovered during Transesophageal Echocardiography (TEE) studies; rates for those under the age of 55 range from 11% to 43% [1].

Description

PFOs have been connected to ischaemic stroke, cryptogenic stroke, migraines and other medical conditions. For patients who have had cryptogenic or ischaemic strokes, percutaneous closure of PFO is presently the primary method utilised to prevent ischaemia strokes. Long-term follow-up studies have shown that catheter-based PFO closure is associated with a lower incidence of recurrent ischaemic stroke in patients with cryptogenic stroke when compared to pharmacological therapy alone. Due to global population ageing and increasing rates of chronic illness survival, the incidence and prevalence of cardiovascular problems, including Atrial Fibrillation (AF), valvular disease and congestive heart failure, are on the rise among the elderly population. In 2016, 46.3 million persons worldwide had Atrial Fibrillation (AF), according to the Global Burden of Disease survey. Stopping an AF-related stroke by percutaneous closure of the left atrial appendage has become a feasible approach. Transseptal access for Pulmonary Vein Isolation (PVI) is currently considered the gold standard for catheter ablation of paroxysmal and early persistent AF [2].

Mitral Regurgitation (MR) is another common valvular disease that can be treated with a catheter because of the MitraClip device. It is an alternative for those who are not eligible for surgery or who are at high surgical risk. Interventional therapies such as Left Atrial Appendage Closure (LAAC) and catheterbased mitral valve replacement require transseptal puncture. Nevertheless, it is challenging to re-enter the left atrium through the atrial septum after a PFO closure because to the significant barriers provided by the metal discs on both sides. At this point, it would be difficult to puncture the septum and proceed with the next procedure successfully. There have been reports of left heart catheterization after implantation of atrial septal occluders [3].

Fitzpatrick et al. described five examples of transseptal catheterisation for arrhythmia ablation after occluder implantation. In one case, a 47-year-old male patient had an attempt to have an 8F SL0 sheath punctured near the central button using an SJM BRK-1XS Brockenbrough needle. The surgery failed despite repeated balloon dilation because the Occluder's mesh structure recoiled after deflation and obstructed the sheath passage. Consequently, by utilising the region around the disc edge with the lower wire density, the operator was successful. Two more patients were successfully accessed through the edge of the discs. Notably, the massive effort required to distort the atrial septum raised the likelihood of posterior wall perforation or device-related embolisation. This woman, 59 years old, had undergone occlusion 15 years prior and her initial attempt at puncturing the septum had failed. Fitzpatrick et al. suggested that intraprocedural DSA, TEE and CT imaging are crucial for these complex procedures because of the increased risk of complications like aortic puncture, perforation into the pericardial area and device-related issues. Additionally, there is more risk to the operator while employing these methods. Though theoretically possible, such advanced techniques must to be avoided wherever possible [4].

After the implantation of a PFO occluder, we have created a nickel-titanium alloy occluder with puncturable properties to allow transseptal puncture for minimally invasive left-sided heart surgeries. This occluder is shaped like a typical right atrial disc, with a biodegradable membrane to restrict blood flow and puncturable zones. There is a very dense weave in the left atrial disc, which resembles a "clover". Even in the absence of a blocking barrier, the structure's close weave is sufficient to halt blood flow [5].

In order to ensure that the boundary of the puncture area is visible under DSA fluoroscopy, tantalum markers were put on the metal wires at the edge of our constructed asymmetric PFO occluder, which preserved a puncturable area. Further CT scans or TEE examinations are not necessary to establish the puncture location because the puncture spot on the occluder is closely connected to the atrial septum. Furthermore, because the puncturable portion of the atrial septum lacks a metal mesh structure, the puncture needle can pass through it with little effort. This may help prevent risks associated with overuse of force, including as posterior wall perforation, atrial septal distortion and occluder displacement [6].

According to earlier studies, individuals who had a Patent Foramen Ovale (PFO) occluder implanted experienced an increased risk of arrhythmias, particularly atrial fibrillation. Compared to the medication therapy group, patients who received transcatheter PFO closure had a quintupled risk of experiencing new-onset atrial fibrillation. This rise, which mostly happened in the first 45 days after the surgery, could manifest as either persistent or sporadic atrial fibrillation. The event may have been caused by the occluder applying pressure to the atrial septum.

The metallic structure of the occluder adhering to heart tissue may result in larger electrical conduction routes, the occluder itself may produce an inflammatory reaction or the technique itself may generate atrial stimulation. However, the metallic component of the dual-disc has been greatly reduced with the introduction of the new occluder. Both the metal coating on the atrial septum and the area of contact between the occluder and the atrial septal tissue are greatly diminished [7].

In addition to reducing tissue oedema, fibrosis and inflammation, this releases tissue compression. Theoretically, cardiac arrhythmias can be significantly decreased in frequency.

A few issues arose during the experimental research phase. For instance, it has been seen that even after the septal puncture needle has passed through the interatrial septum from the right side to the left, the left atrial disc may still be a source of obstruction. To decrease the severity of this issue, adjust the puncture angle. Moreover, decreasing the surface area of the left atrial side disc preserves the occlusive efficacy while lowering the probability of these blockages [8].

Conclusion

An experimental study has established the effectiveness of the asymmetric, single-rivet occluder intended for interatrial septal puncture sites. After the occluder is implanted, further interatrial septal puncture procedures may be made easier by the preserved puncture zone. This innovative occlusive device has cleared the way for later left-side cardiac procedures by proving that it is feasible to create an access via the septum after occlusion, as seen by its improved occlusive effectiveness, biocompatibility and puncturability in trials.

References

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