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Isolated ICD lead revision, extraction unwarranted in asymptomatic patients
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BOSTON — The risk for complications from implantable cardioverter defibrillator lead revisions and extractions is similar to that of the rate of electrical failure of a certain set of recalled leads, according to an analysis of Canadian data presented at the Heart Rhythm Society Annual Scientific Sessions.
Because of that, isolated ICD lead revision or extraction in asymptomatic patients should not be performed, Ratika Parkash, MD, FHRS, from Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax, Nova Scotia, said during a presentation.
Ratika Parkash
Parkash and colleagues analyzed patients at 15 Canadian centers who had received cardiac devices with 20 models of ICD leads (Riata, St. Jude Medical), which were recalled because of cable externalization. In total, there were 2,707 patients (mean age, 63 years; 19% women) in the study, accounting for 59.7% of the Riata leads implanted in Canada, Parkash said.
The researchers sought to determine the electrical and structural failure rate of the leads over time, and to determine the predictors of lead failure. The primary endpoints were death attributable to lead malfunction, incidence of cable externalization by lead model and incidence of electrical lead failure by lead model. Mean follow-up was 7.5 years.
According to the researchers, 378 patients underwent lead revision, most commonly because of electrical abnormalities (42.1%), lead dislodgement (18.3%), infection (12.4%) or cable externalization (11.6%).
The 10-year rate of electrical failure for 8F leads was 5.9% and the 8-year rate of electrical failure for 7F leads was 5.2%, Parkash said. The rates of cable externalization were 7.4% in the 8F leads and 4.9% in the 7F leads. Differences between the lead types in those measures were not significant, she said.
Among the 1,187 patients who underwent radiographic screening at the discretion of each physician, the rate of cable externalization was 6.7% (8F group, 7.2%; 7F group, 4.8%). Of those, 10.1% also had electrical failure (8F group, 9.4%; 7F group, 13.3%), according to the researchers. “There was a trend toward higher rate of electrical failure with cable externalization, but this did not reach statistical significance,” Parkash said.
In a univariate analysis, the researchers found that compared with those without electrical failure, those with electrical failure were younger, less likely to have a primary indication for an ICD, had better left ventricular ejection fraction and were more likely to have NYHA class I or II HF (P < .01 for all).
Multivariate predictors of lead failure were age per 10 years (HR = 0.84; 95% CI, 0.73-0.95) and LVEF per 10% (HR = 1.26; 95% CI, 1.1-1.45), Parkash said.
An analysis of 253 patients who underwent lead revision indicated that the major periprocedural complication rate was 6.32% (8F group, 5.52%; 7F group, 8.33%) and that there were two deaths associated with lead revision, one from the 8F group and one from the 7F group, both due to sepsis.
Another patient died due to lead malfunction, Parkash said.
“Given these data, isolated lead revision or extraction due to advisory is not warranted,” she said. – by Erik Swain
Reference:
Parkash R, et al. Abstract LBCT02-03. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 13-16, 2015; Boston.
Disclosure: Parkash reports receiving consultant fees/honoraria from Bayer HealthCare, Pfizer and St. Jude Medical and research grants from Bayer/Schering Pharma, Medtronic and St. Jude Medical.
Perspective
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Andrea M. Russo, MD, FACC, FHRS
This presentation was based on information from a Canadian registry of devices, examining Riata leads that are on advisory. It provides really important data regarding longer-term follow-up on Riata leads, both 7F and 8F leads, which were implanted in Canada. The prospective registry of 15 centers in Canada looked at long-term failure rates, including both for mechanical failure and electrical failure. Importantly, the researchers identified that electrical failure does continue to increase over time, suggesting the importance of close patient follow-up. This applies to both 7F and 8F lead types. Similar to prior lead failure studies, younger patient age and higher ejection fraction predict lead failure in multivariable analyses.
What we don’t know right now — and hopefully future analysis of the registry data will help — is how to identify the best way to predict failure in these patients, including which tests might be most helpful in identifying early signs for failure. For example, it appears that being able to see cable externalization or “structural failure” on an X-ray doesn’t always correlate with electrical failure. Is there some other way, such as a high-voltage test in the electrophysiology laboratory, that might be able to better identify a short in a lead? We look forward to a deeper look into the data to help address this question.
As a more global issue, registries in general may play a future role in earlier detection of lead problems. Perhaps use of more real-time registry data with ongoing surveillance might help us detect earlier lead failures and reduce the number of leads implanted that are at high risk for failure.
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