Cardiovascular Implantable Electronic Devices -> Leads & Electrodes: -> Implantation D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-105 - Characterization Of The Substernal Space: CT Image Results For Exploration Of Difference In Sternum-heart Distances In Patients With And Without Median Sternotomy (ID 442)


Background: The Extravascular (EV) ICD provides alternative to commercially available ICDs. However, feasibility of implanting a lead under the sternum in sternotomy patient is unknown.
Objective: To characterize the sternum-heart distance in patients with and without prior sternotomy and to assess whether ICD lead implant in the substernal space of prior sternotomy patients is feasible.
Methods: The distance between sternum and epicardium were measured from CT images in 40 patients (67.5% male, 73±10 years; 20 with prior sternotomy, S-group; 20 without prior sternotomy, NS-group). In each transverse view, the distance measures were averaged along the midline and ±10 mm lateral to the midline, and then segmented into 4 regions using the xiphisternal junction as the anatomic landmark (Fig. A). A one-tailed t-test was utilized to compare the distances for each region.
Results: Fig. B shows significant differences of the distances between sternum and epicardium in Region 1 (S-group: 3.8±3.0 mm, NS-group: 7.0±3.5 mm, p=0.02). No difference was observed in Region 2 (5.4±4.3 mm vs 7.8±5.9 mm, p=0.19), Region 3 (10.3±7.7 mm vs 13.6±8.0 mm, p=0.22) and Region 4 (13.6±8.8 mm vs 15.7±5.9 mm, p=0.37). S-group patients <65 years tended to have a larger distance in Region 1 (p=0.17; Fig. C).
Conclusion: We found narrower lead implanting spaces for patients with prior sternotomy compared to those without prior sternotomy, but it appears to be feasible to position a substernal lead in patients with prior sternotomy.