Beyond Tunnel Length: Tunnel Width-Derived Cover Index Improves Device Sizing and Predicts Outcomes After...

Residual shunting after transcatheter patent foramen ovale (PFO) closure occurs in up to 25% of patients and increases the risk of recurrent neurologic events. Existing sizing strategies may be insufficient as they overlook the tunnel's complex 3-dimensional (3D) anatomy. The aim of this study was to evaluate PFO tunnel dimensions with 3D transesophageal echocardiography (TEE) and determine whether tunnel width (TW) metrics would predict procedural outcomes.

We retrospectively analyzed 102 patients undergoing PFO closure (n = 82 with follow-up bubble study). 3D-TEE was used to assess TW at right (TW_RA) and left (TW_LA) atrial openings, tunnel length, tunnel height at RA opening, and presence of septal aneurysm. We calculated an absolute TW_RA cover index for each patient as follows: RA disc diameter - TW_RA. Receiver operating characteristic curve analysis was used to determine predictors of procedural outcomes.

Tunnel length did not correlate with TW_RA, TW_LA, or tunnel height; TW_RA (and not tunnel length) was significantly larger in patients with a septal aneurysm. TW_RA (area under the curve [AUC], 0.79; P < .001) and derived cover index (AUC, 0.88; P <.001) predicted residual shunting; a cover index of ≤9.5 mm provided optimal sensitivity (90%) and specificity (78%). The rate of residual shunting was 2% in patients with a cover index of >9.5 mm (median follow-up, 6.3 months). The TW_RA cover index also predicted the need for device upsizing (AUC, 0.99; P <.001; optimal cutoff ≤4.5 mm). Tunnel length did not predict either outcome.

Despite its widespread use for sizing, tunnel length is unrelated to TW, septal excursion, or procedural outcomes after PFO closure. In contrast, TW-based metrics reliably predict outcomes, underscoring their potential to refine sizing strategies in patients undergoing this procedure.