Editor’s Note: The following guest post is published with the permission of its author, Edward J. Schloss, MD, (Twitter ID @EJSMD) the medical director of cardiac electrophysiology at Christ Hospital in Cincinnati, OH.
St. Jude’s troubled implantable defibrillator leads came under a fresh layer of scrutiny today with new FDA imaging recommendations and post-market study requirements. For the first time, the newer generation Durata and Riata ST Optim leads have been placed under enhanced review.
The problems with St. Jude’s ICD leads date back to the first reports of Riata model lead externalization in 2010. By December 2011, FDA had issued a class I recall of both Riata and Riata ST models based on the growing body of evidence that these leads had potential for insulation breakdown. Additional studies have now also shown increased electrical abnormalities of these leads. Next generation Durata leads, while sharing significant structural similarities to Riata and Riata ST have thus far performed well in prospective trials (See my earlier post about the full scope of the problem.)
FDA Calls for X-Ray Screening of Riata and Riata ICD Leads
Today FDA issued a press release calling for patients to undergo “x-ray or other imaging alternatives” to look for externalization of St. Jude Riata and Riata ST leads. Specific timing and frequency of testing is not stated and no recommendations are given as to how to act on abnormal findings. In the release, FDA indicates that x-ray information “will help health care providers develop individualized patient treatment plans.” These recommendations may come as a bit of a surprise to the electrophysiology community. Routine screening for externalization, while favored in some centers, has not been recommended by St. Jude Medical or the Heart Rhythm Society. At the Riata Leads Summit this past January, only about half of physician attendees polled planned to do this screening, as I previously reported.
The link between externalization and lead failure remains uncertain. During a St. Jude’s sponsored webinar posted last month, Dr. Neal Kay reported “more than 85% of the externalized conductors continue to function normally.” Later in the lectures, numerous discussants referred to Riata externalization as “cosmetic.” St. Jude’s data from the Riata Lead Evaluation Study showed externalization rates of 24% in Riata and 9.3% in Riata ST based on prospective fluoroscopic data, but electrical data from that trial is still being collected and has not yet been reported. A recent VA trial reported increased electrical failures in these leads, but did not include x-ray evaluations.
Significant controversy remains on how to manage externalized ICD leads that have normal electrical testing. At the HRS Scientific Sessions this past May, Dr. Roger Carillo advocated transesophageal echocardiographic imaging of externalized leads and systemic anticoagulation if thrombus is visualized, but this strategy has not been widely adopted. He and others have warned that extraction of this lead can be technically challenging with potential for hazard to the patient. In today’s notice, FDA “caution[s] against routine removal of leads without careful evaluation of benefits and risks to the individual patient.”
Although FDA indicates that physicians should use imaging data to develop “individualized treatment plans” for these patients, the FDA does not provide additional guidance regarding how to manage this evolving and complex problem.
FDA Call for New Post Market Surveillance Studies of Multiple St. Jude Leads
The FDA is also asking St. Jude to perform three-year post market surveillance studies (termed Section 522 studies) on multiple leads within their portfolio. ICD leads named include Riata, Riata ST, Riata ST Optim and Durata. Also included are QuickSite and QuickFlex LV leads which had previously been named in a product recall in April 2012 with reported externalizations visually similar to Riata.
The inclusion of Durata and Riata ST Optim leads in these studies is a new and important development. These leads, although structurally similar to Riata ST leads, include an additional layer of silicon/polyurethane copolymer (Optim) outer insulation for enhanced abrasion resistance. St. Jude has aggressively defended Optim as being protective against externalization and electrical failure. FDA investigators appear not be as convinced. In a Wall Street Journal article about the FDA actions, one FDA official, Dr. Mitchell Shein, indicated that Durata is “’sufficiently similar’ to the recalled Riata product to merit closer examination.” In addition, according to the Journal, FDA is now asking St. Jude to include routine fluoroscopic evaluation of Durata in its post-market study.
Wall Street took a sour view of today’s developments. St. Jude Medical closed at $36.87, down 4.38% on afternoon trading coinciding with the FDA announcement.