Editor’s Note: Edward J. Schloss (Twitter ID @EJSMD), the medical director of cardiac electrophysiology at the Christ Hospital in Cincinnati, OH, returned yesterday from the Riata ICD Lead Summit. Dr. Schloss has kindly forwarded his summary of the meeting to CardioBrief. “As the audience was restricted to clinicians and St. Jude personnel, this may be the first and only public account of this meeting,” wrote Dr. Schloss. (As the editor of CardioBrief, I would like to express my keen disappointment that a meeting of this general importance was closed to outside observers, including journalists, analysts, and representatives from other companies.)
Report from the Riata ICD Lead Summit
by Dr. Edward J. Schloss
Sixty-three registered health care professionals and St. Jude Medical industry representatives gathered today at the Minneapolis Airport Marriott Hotel for the Riata ICD Lead Summit. This conference, organized by The Minneapolis Heart Institute Foundation and Mayo Clinic, was organized to review available data and develop a consensus regarding St. Jude ICD leads currently on recall or subject to increased scrutiny.
Course directors Robert G. Hauser, MD and David L. Hayes, MD presided over a series of lectures and panels of experts in the field.
Dr. Hayes first polled the conference attendees about the current landscape. A full 35% of attendees thought Riata leads posed a greater concern to them than the Medtronic Fidelis recall. In addition, 41% felt enough concern about the currently marketed Durata lead that they have elected not to implant this lead. The Durata lead, although not on recall, shares many design elements with the Riata ST.
Dr. Hauser reviewed available clinical and engineering data. The failures of Riata leads appears to be due to a unique “inside-out” form of lead insulation abrasion. In some, but not all cases, lead cables have been shown to externalize. Commonly, however, externalization is not associated with failure and vice versa. There is no single common sign of lead failure on electrical measurements.
One common theme throughout the conference was the unknown significance of lead cable externalization. Dr. Ernest W. Lau presented the early data from Northern Ireland that first brought to light the problem. With systemic fluoroscopic screening, his group showed a 15% incidence of externalization in a population that included a high incidence of single coil leads. Later in the day, Dr. Christopher Ellis of Vanderbilt University presented his US data showing an even higher incidence of 26% fluoroscopic lead cable abnormalities in a population with predominantly dual coil leads. Both groups found that leads with externalized conductors commonly have normal electrical performance.
St. Jude engineering bench data was discussed showing normal electrical and mechanical performance of externalized cables, prompting medical director Dr. Mark Carlson’s admonition “the appearance of an externalized conductor alone should not provoke an overreaction.” There was concern among the clinicians, but no consensus reached about what would be the expected natural history of these electrically silent insulation breaches. Carlson emphasized that no electrical failures St. Jude has observed have been independently due to cable insulation breach. These and other observations prompted some attendees to suggest that externalization may simply be a “symptom” or epiphenomenon related to lead electrical failure. Only 146 Riata leads have been returned to St. Jude for analysis and a call was made to the medical community that better product reporting is essential.
Electrical performance of Riata leads was looked at systematically in an industry independent multicenter retrospective trial reported by Dr. Raed H. Abdelhadi from Minneapolis Heart Institute. In a seven center collection of 1060 leads (773 8f Riata, 287 7F Riata ST), the overall incidence of measured electrical abnormality was 5.8%. The performance when plotted was intermediate between non-recalled high performing leads and Medtronic Fidelis. There was no systematic search for externalized conductors in the study. Dr. Edmund C. Keung presented similar data from the VA registry also in the US.
St. Jude Medical Industry personnel were a strong presence at the meeting and were the only non-clinicians present. Attendees repeatedly sought comments regarding engineering data and failure analysis. Dr. Carlson described an ongoing prosective multicenter trial of upwards of 500 Riata leads looking systemically at fluoroscopic appearance and electrical performance.
In afternoon sessions, Dr. Laurence Epstein from Brigham and Women’s Hospital presented strategies regarding lead extraction of Riata. Unique challenges with this lead were shown relating to the behavior of the externalized cables. He repeatedly emphasized that experience and preparation is critical for anyone planning to extract this lead. There was a strong consensus that this lead may be difficult to extract and should not be removed prophylactically.
Closing out the presentations, Drs. Kenneth Ellenbogen and Charles Swerdlow presented diagnostic strategies for follow up of Riata leads. Both agreed that detection of failures has been challenging given the varied and sometimes subtle changes seen. Dr. Raveen Bazaz of University of Pittsburgh Medical Center presented his data showing a correlation between cable externalizations and the angles of deflection of the ICD lead within the right heart. He postulated that a radiographic index could be created using these angles to predict future externalizations.
The attendees were polled again at the completion of the session and already high concerns were amplified. A higher proportion than earlier (58%) of those polled felt the Riata situation was a more serious problem than the Fidelis recall and 44% indicated that they had enough concern about the market released Durata lead that they would not be using this in the future. Despite HRS consensus recommendations to the contrary, 55% of attendees favored routine repeated fluoroscopic monitoring.
Conference organizer Hauser closed out the session expressing frustration that industry and FDA has known about Riata problems for over a year and is only now collecting prospective data. He emphasized that the Durata lead needs to be watched more closely: “put it under a microscope.”