In-tunnel closure of patent foramen ovale with a FlatStent EF™

Abstract

Background: Devices for percutaneous closure of patent foramen ovale (PFO) are traditionally based on two opposing discs, leaving significant surface areas exposed in the left and right atrium. The FlatStent EF™ PFO Closure System (Coherex Inc., Salt Lake City, USA) represents a major departure from these devices because it is designed to focus primarily on the PFO tunnel, leaving minimal foreign material behind.

Aim: To investigate the patient selection, effectiveness, and safety of in-tunnel closure with a FlatStent EF™ in patients with PFO of ≥ 4 mm tunnel length and < 12 mm diameter at preprocedural transoesophageal echocardiography (TEE).

Results: Among 46 consecutive patients undergoing PFO closure, a FlatStent EF™ could be implanted and resulted in initial successful closure (< 5 bubbles during Valsalva manoeuvre) in 21 (46%) patients. TEE at 162 ± 40 and 317 ± 162 days after implantation demonstrated functional closure in 90% and 95% of cases, respectively. No device or air embolisation, pericardial effusion, or thrombus formation was documented. Small in-tunnel peri-device colour Doppler left to right flow was documented in 10% and 2-6 mm protrusion of FlatStent EF™ along right atrial septum without any residual flow/bubble shunting in 14%. Patients with suboptimal closure (> 5 bubbles during Valsalva manoeuvre and/or in-tunnel colour flow) had shorter tunnel on preprocedural TEE (5.3 ± 1.5 vs. 10.8 ± 3.5 mm; p = 0.003). There was no difference in TEE diameter (1.8 ± 0.5 vs. 2.0 ± 0.5 mm; p = 0.38) and stretched diameter by sizing balloon (6.3 ± 2.5 vs. 6.3 ± 1.0 mm; p = 1.00).

Conclusions: In-tunnel PFO closure with a FlatStent EF™ represents an effective and safe option only in carefully selected patients with long tunnel (> 4 mm) regardless of the diameter if it is < 12 mm. These criteria are fulfilled in < 50% of consecutive candidates for PFO closure. The new phenomenon of in-tunnel peri-device flow and FlatStent EF™ protrusion along the right atrial septum were documented during systematic TEE follow up.