A study, published ahead of print in Circulation Cardiovascular Quality Outcomes, shows that the Data Extraction and Longitudinal Trend Analysis (DELTA, Coping Systems) system could have triggered a sustained safety alert about the Sprint Fidelis lead two years before the product was taken off the market.
Medtronic withdrew its Sprint Fidelis implantable cardioverter defibrillator lead in October 2007 after the FDA issued a voluntary recall notice following post-market surveillance reports of lead failure. In their new study, Robert Hauser (Minneapolis Heart Institute Foundation, Minneapolis, USA) and co-authors claimed that post-market surveillance may miss early safety signals because it (in the USA) “depends largely” on voluntary reporting of adverse events. They added that new detailed clinical registries and remote monitoring databases, such as Medtronic’s CareLink, “has created avenues for improving medical device surveillance. Opportunities have emerged for automated tools that prospectively monitor large device databases for early low-frequency adverse events while implementing statistical techniques to compare suspect devices with established products that are performing well.”
Therefore, Hauser et al used the automated surveillance tool DELTA, which simultaneously accumulates data from multiple devices and monitors independent data sets, to review data from a registry of patients who received the Sprint Fidelis lead and those who received, for comparison purposes, Medtronic’s Quattro Secure lead (known to be a well performing lead). Their hypothesis was “DELTA would have identified the Fidelis problem earlier than traditional surveillance techniques.”
Using DELTA in a stimulated prospective full-cohort survival analysis, Hauser et al found that a single Fidelis lead failure that occurred 13 months after an implant (October 2005) triggered a DELTA alert that was sustained for all subsequent monthly survival analyses. In a stimulated prospective propensity-matched survival analysis, DELTA triggered an alert in July 2006 that lasted until January 2007. The alert returned in June and persisted for the remaining months of the study. As the first DELTA alert occurred two years before the product was withdrawn from the market, Hauser et al claimed that if DELTA had been used for safety surveillance, it could have led to the Sprint Fidelis lead being withdrawn from the market at an earlier date. They said: “We speculate that by early 2007, Fidelis leads would have been removed early from the market or infrequently used. Indeed, as the Fidelis failure trend emerged in 2006, it is probable that many physicians would have opted to limit their use of Fidelis leads. This proactive approach to post-market surveillance has the key attributes of timeliness and scientific rigour while minimising the chance that clinical or operator variables could account for the observed failures.” However, they added that an early DELTA alert might not have automatically led to the product being withdrawn but rather such an alert would be “hypothesis-generating”, leading to additional confirmatory studies.
Hauser told Cardiac Rhythm News: “If DELTA had been applied prospectively to a robust Sprint Fidelis registry, thousands of patients could have been spared the cost of monitoring and replacing their leads.”