Patient Management: When ICD Leads Go Awry

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Source: DeLurgio-Emory.jpg - ICD - David B. DeLurgio, MD
David B. DeLurgio, MD, of Emory University Crawford Long Hospital in Atlanta, requires periodic imaging of patients with certain recalled leads.

Implantable cardioverter-defibrillators (ICDs) are true lifesavers, but like all devices, their components potentially can malfunction. The natural life of a well-performing ICD lead, for instance, is about 10 years or so; however, several models of leads have higher rates of failure and a few have been subject to recall. Properly managing a patient with a failing lead or a recalled lead is a clinical challenge, due to a host of factors that must be balanced when determining the best interests of the patient.

Recently, electrophysiologist David B. DeLurgio, MD, of Emory University Crawford Long Hospital in Atlanta, had a difficult conversation with a patient in whom he had implanted an ICD in 2005. The ICD had been operating properly and twice had delivered appropriate shocks to the patient. But the patient had a recalled lead implanted. Like all recipients with this same lead in DeLurgio’s practice, the patient has regular fluoroscopic examinations, and the most recent one showed extrusion of several segments of the lead.

New vs. Known

New models of ICD leads continue to enter the market, each accompanied by a marketing effort that trumpets its innovations and superiority over existing models. But Raed Abdelhadi, MD, of the Minneapolis Heart Institute, points out that new leads may not include substantial information about how that lead will perform over time.

This is a key point for both physicians and patients, as understanding the typical mechanism of failure of each model is crucial for optimum patient monitoring and management. Yet this information is not typically available until long after a new product is introduced to the market, and that can make managing the patient more challenging.

"There are no strict reporting requirements, and many of us have the sense that failures are under-reported," he says. "If post-marketing data were collected and disseminated in a more systematic way, we would have a better understanding, sooner, of the risks to watch for and could try to prevent them."

To that end, Abdelhadi encourages physicians to report all lead dysfunction to the manufacturers and to the FDA. He also suggests returning all damaged, extracted leads to the manufacturers. In this way, practicing physicians can contribute to the body of evidence about the specific performance of the devices their patients are receiving, add to the knowledge base and, ultimately, provide a better experience for the patients who depend on these life-saving devices.

The patient was due for a generator replacement, and DeLurgio counseled him that the lead should be replaced as well as the battery—a more difficult and involved procedure. “There was no electrical malfunction, but there was clearly structural malfunction that may be a harbinger of eventual electrical malfunction,” DeLurgio says. “And in a patient like this one, who is likely to need a life-saving shock again, we want to replace that lead.”

With this patient, the decision proved relatively easy, but that is not always the case. Many questions arise when managing ICD patients with suspect, faulty or recalled leads: When is it prudent to replace the lead, or when is close monitoring the better choice? Is it better to extract the old lead, or is extraction too risky for this patient? How best to discuss these issues with the patient, to ensure informed, shared decision-making? There are no hard and fast answers, but after years of experience, there are some emerging schools of thought.

Facing the inevitable

Approximately 400,000 patients receive ICDs every year in the U.S., and more than 3 million patients in the U.S. currently have ICDs (Circulation 2011;123:e378-380). Even if a particular lead model has no documented performance problems, leads have a finite life expectancy. When a patient receives an ICD prior to age 60, it is likely that lead replacement will be necessary at some point. Younger patients and patients who receive leads that do not perform properly may undergo several lead replacements.

“Even well-performing leads have a failure rate of about 0.3 percent per year,” says Jason C. Rubenstein, MD, an electrophysiologist with the Medical College of Wisconsin in Milwaukee. “And leads that have performance problems can have failure rates as high as 1 or 2 percent per year.” According to a 2011 study modeling costs of ICD lead management in the U.S., Medicare will spend approximately $287 million over five years on the management of high-failure leads (Heart Rhythm 2011;8[8]:1192-1197).

Leads fail in different ways. For the physician, understanding the mechanism of failure is critical, and knowing the signs of failure and the attendant risks are crucial to proper patient management, says Raed H. Abdelhadi, MD, an electrophysiologist of the Minneapolis Heart Institute.  
“If my patient is dependent on the device for primary prevention of sudden cardiac death and the lead is showing signs of electrical malfunction, the decision likely will be different than if the patient relies on the device for secondary prevention and the mechanism of failure is structural,” he says.

There are several well-understood markers for lead failure. Younger, more active patients tend to have more lead failures because their activity puts stress on their leads. Evidence suggests that smaller diameter, more flexible leads fail at a higher rate. Defibrillator leads have a shorter life expectancy than pacemaker leads because they are larger and more complicated.  

Monitoring & assessment 

All ICDs are capable of being monitored remotely, and remote monitoring is now the standard for almost all patients regardless of the model of lead implanted, says DeLurgio. Potential lead failure is one of the eventualities that remote monitoring is designed to detect.
According to Robert G. Hauser, MD, a cardiologist at the Minneapolis Heart Institute, signals of possible lead failure include changes in electrical parameters like noises in the lead, gradual changes in the amount of energy to the patient’s heart (threshold), gradual decrease in the size of the signal from the heart and other electrical abnormalities. Inappropriate shocks can indicate lead failure.

But not all lead failures are heralded by electrical changes. As the case of DeLurgio’s patient demonstrates, some lead failures are electrically silent.   

Mechanisms of failure in leads that have been recalled from the market tend to be quite specific. Insulation erosion leading to extrusion of the lead typically is the mechanism of failure of the Riata (St. Jude Medical) leads, and patients are often asymptomatic. In a recent study, researchers performed a fluoroscopic examination of all living Danish recipients of the Riata leads, and found that 11 percent of the leads had externalized (Heart Rhythm, online Feb. 15). Another multicenter study found that after a mean time of implantation of 63 months, 14.3 percent of Riata leads had externalized, and most of these problems were electrically silent (Circ Arrhythm Electrophysiol 2012;5:809-814).

Some electrical malfunctions signaling Riata lead failure have been reported, according to Hauser, primarily failure to pace and oversensing leading to inappropriate shocks. There have been a few incidents of complete device failure, with the ICD failing to correct a patient’s arrhythmia, leading to death. However, these events are rare, and periodic imaging to assess structural integrity is the primary method of monitoring lead performance in patients with Riata leads. For instance, in DeLurgio’s practice, patients with Riata leads undergo imaging every six months.

In contrast, the Medtronic Sprint Fidelis lead failed most often because of a fracture of the conductor to the ring electrode. As a result, it would oversense and provide inappropriate, painful shocks. According to Hauser, these problems became apparent by 2007, and by 2009 software was available that recognized events that could lead to the inappropriate shocks. Once the software was loaded into the defibrillator, it could sense the malfunctions that would lead to an inappropriate shock and the patient’s pulse generator would beep. The beeping would signal that the device was not functioning properly, and the patient would then visit his or her physician to revise or remove the lead before the device delivered inappropriate shocks. Monitoring of patients with Fidelis leads has thus become simpler.

Abandon or extract?

When a lead has failed or is failing, the patient and his or her physician may decide to abandon the lead but keep it in place and add another lead, or to extract the lead and replace it. This is a complex decision based on the individual circumstances of the patient, and there is some controversy surrounding the risks and benefits of abandonment vs. extraction.

The Heart Rhythm Society has issued advisories that assist in decision-making. In some cases extraction is the only viable option, such as when a device has become infected (Circulation 2011;123:e378-e380). In addition, lack of space to add another lead, venous occlusion, lead-to-lead interactions and pain from multiple leads are all strong indications for extraction. Weaker reasons are the presence of multiple leads or the request of the patient.

Scar tissue forms around leads placed in veins running into the heart chambers as part of the natural healing process. In the past, physicians used traction to extract a lead, which could result in fragmentation or damage to the heart or veins. Recently tools like power sheaths and laser sheaths have improved the extraction process, cutting the scar tissue so that less force must be applied to remove the old lead.   

The risks of extraction were quantified recently by Rubenstein and Michael P. Curley, MD, also of the Medical College of Wisconsin. They used the Nationwide Inpatient Sample to identify predictors of mortality in patients undergoing lead extractions. Their research was presented as a poster at the 2013 scientific session meeting of the American College of Cardiology.

Curley and Rubenstein identified 33,121 lead extractions that took place between 1998 and 2009 and found that 584 of these patients died during the index hospitalization, for a mortality rate of 1.76 percent. The researchers also identified independent predictors of inhospital mortality, with sepsis being the strongest predictor, followed by renal failure, congestive heart failure and electrolyte disorders and coagulopathy.

“This is the most robust data I’m aware of regarding mortality associated with lead extraction,” says Rubenstein. “But we don’t know that these patients died from lead extraction; the database just tells us that they died during the same hospitalization in which they had the lead extraction. We know that lead extraction is no more dangerous than these data indicate, but it is safer than these number indicate because we know that not all of these patients died from the lead extraction.”

During the study’s time period, inhospital mortality of patients undergoing lead extraction rose steadily, and in 2009 it approached 3 percent. But after controlling for other comorbidities, the year of extraction dropped out as a significant variable. “My guess is that the population on which extractions were being attempted became sicker over the study period,” Rubenstein explains.

He carefully will advise patients who are considering extraction on expected risks and benefits, especially if they have comorbidities that increase their risk of complications. Although there are some risks associated with abandoning a lead, such as the possibility of vein occlusion or lead-to-lead interaction, in an older patient the risks of a major procedure to extract a lead may outweigh such possibilities. In addition, “The data indicate that the complication rate for Fidelis lead extraction is higher than that for other leads, and so it may be advisable to just monitor the Fidelis patient carefully and replace, but not extract when it [the lead] fails,” he suggests.

On the other hand, DeLurgio and colleagues at Emory often recommend against abandoning Fidelis leads, because they have noticed that when they replace the generator of a device with a Fidelis lead, they see a spike in lead failures over the next two months. “It may be that manipulating the leads hastens the failure process,” DeLurgio speculates.  

Research supports that observation. In one single-center study, generator exchange increased the rate of Fidelis lead failure tenfold compared with matched controls (Heart Rhythm 2012;9[10]:1615-8).

Shared decision-making

Whether advising abandonment or replacement, clear and transparent communication is essential. “The patient is entitled to all the information we have available, to 100 percent communication,” says Hauser.

Patients can be influenced by media reports, says Rubenstein, and may demand extraction of a recalled lead even if the device is working properly. “I try to give them both sides of the equation, to balance the possibility of device failure against the risks of extraction,” he says. “That is where our data is very useful, as it can add some granularity to the conversation as we discuss the factors that make extraction more or less risky.”

Ultimately, the choice to abandon or extract must be a matter of patient preference. “[Extraction] is a big deal to patients,” says DeLurgio. “Patients [with failing leads] can find it psychologically damaging, can feel that they got the short end of the stick. But it is important to remember that these devices have saved a lot of lives, and so even though we get these kinds of problems we are still dealing with a good technology that continues to improve.”

Lead with the lead

"What lead are you planning to use?" is the most important question patients should ask when discussing implantable cardioverter-defibrillator (ICD) implantation with their physician, says Robert G. Hauser, MD, a cardiologist of the Minneapolis Heart Institute. Many patients will not know to ask this question, however, and therefore it is incumbent upon the physician to choose carefully.

Hauser urges physicians to make responsible choices when implanting leads and manufacturers to place patient safety ahead of market share. He wrote a commentary in which he reviewed the success of ICDs in preventing sudden cardiac death, but lamented the eagerness of many physicians to adopt leads of smaller diameter without evidence that they were more effective (Heart Rhythm, online Feb. 15).

A recent study in Italy, for example, found that small diameter leads (less than 8F) failed at a rate five times that of larger diameter leads and that small lead diameter was an independent predictor of failure (Heart Rhythm 2012:10[2]:184-190). However, there is no homogeneity in the mechanism of failure of the small diameter leads, which may indicate that design, rather than diameter, drives the failures. Even so, the advantages of smaller diameter leads are unclear. A study conducted at the Genesis Heart Institute in Davenport, Iowa, and presented at the Heart Rhythm Society's 2012 meeting, found that smaller diameter leads did not reduce the incidence of venous occlusions.

In his commentary, Hauser asserted that innovations and improvements in ICDs have focused on design—making the devices smaller, more flexible, etc.—rather than reliability. He suggested that an eagerness to gain market share has spurred manufacturers to introduce new leads without sufficient human studies or data regarding long-term performance.

Noting that ICD implantation is a safe procedure if performed by an experienced operator, Hauser pointed out that the limited durability of the leads is the major driver of poor outcomes, and that "ICD lead extraction has become a subspecialty, including centers of excellence and a thriving industry that supplies the tools," he wrote in his commentary.

Hauser advises physicians to base their lead choices on the product's history and documented performance over time. "There are good leads out there that have been on the market for 10 years and have an excellent track record," he says. "Don't replace a bad lead with another bad lead. There is a tendency to go for the newest, the latest and greatest, but we've learned that is not the right decision."