176-50: Radiographic Screening for Riata Leads is not Useful: Incidence of Occult Insulation Defects with Associated Electrical Malfunction

Introduction: In 2011, the FDA recalled Riata defibrillator leads due to high incidence of high voltage conductor externalization. Current guidelines recommend screening via cinefluoroscopy or two-view chest x-ray (CXR), however externalized leads are often found to be electrically normal on interrogation, while electrical abnormalities can be found in radiographically normal leads. We investigated whether radiography can detect occult insulation defects.

Methods: We conducted a retrospective single center study of patients with successful Riata lead extraction between 2012 and 2014. All patients underwent cinefluoroscopy and device interrogation on the day of the procedure. PA/lateral CXR was performed in all patients within one week of the procedure. Leads were classified as abnormal (clear cable separation), borderline, or normal based on preexisting criteria. Postoperative gross lead findings were reviewed by two independent cardiac electrophysiologists.

Results: Nineteen patients with successful Riata lead extraction were evaluated. Thirteen out of 19 (68.4%) had post-operative evidence of conductor insulation defects, which were likely pre-existing based on evidence of old coagulated blood inside the entire lumen and the use of laser only over the coils. Seven out of 13 patients (53.8%) with postoperative externalization had negative radiographic findings. Majority of patients with evidence of electrical malfunction (8 out of 9 – 88.9%) had evidence of pre-existing conductor insulation defects.

Conclusion: Radiographic screening of Riata leads is not consistent with postoperative findings of lead externalization. A large proportion of patients with negative screening had gross evidence of conductor insulation defects. Many patients with electrical malfunction had negative radiographic screening. Therefore, there may be little utility in radiographic screening per current FDA guidelines. Instead, Riata leads should be regularly monitored and decision for lead replacement based upon evidence of electrical malfunction. Further studies to explore the potential thromboembolic implications of occult lead externalization and need for lead removal are also warranted.