Posted on 08/31/2011

NEW YORK– Implantation of cardiac implantable electrophysiological devices (CIED) is associated with increasing rates of complications and mortality, according to results of 3 studies published in the August 23rd online Journal of the American College of Cardiology.

There have been dramatic increases in the implantation of these devices, largely due to the expanded indications and the aging of the general population. Previous studies have suggested that the complication rates associated with implantation of these devices may be increasing, too.

Infection rates have clearly increased, according to a report from Dr. Arnold J. Greenspon from Thomas Jefferson University Hospital, Philadelphia, Pennsylvania and colleagues. They analyzed the historical trends for CIED infection in the United States between 1993 and 2008 using data from the Nationwide Inpatient Sample.

The incidence of CIED implantation increased by 96%, an average of 4.7% annually (largely due to a 504% increase in implantable cardioverter-defibrillator (ICD) during the interval). At the same time, the incidence of infection increased by 210%, with most of the increase coming between 2004 (incidence, 1.53%) and 2008 (incidence, 2.41%).

The in-hospital charges for a CIED infection skyrocketed during the period, from approximately $75,000 in 1993 to more than $146,000 in 2008, despite hospital stays remaining constant at around 14 days.

Mortality associated with CIED infection also increased, from 2.91% in 1993 to 4.69% in 2008.

“I don't want people to come away with the idea that we need to implant fewer CIEDs,” Dr. Greenspon told Reuters Health by email. “However, there may be things that can be done to mitigate infection in patients that do have a CIED.”

“Further research in order to mitigate this infection burden is warranted,” Dr. Greenspon concluded. “We are currently analyzing the Medicare database to determine what factors are responsible for the increasing infection burden.”

Some of the increases in complication and mortality rates derive from the use of more advanced technology. According to Dr. Paul D. Varosy from VA Eastern Colorado Health Care System, University of Colorado, Denver, Colorado, these rates are higher among patients who receive dual-chamber ICDs than among patients who receive single-chamber ICDs.

They examined the complication rates of these 2 generations of ICDs using data on 104,049 patients in the National Cardiovascular Data Registry ICD Registry.

Although dual-chamber ICDs were implanted in 62% of these patients, only 40.4% of dual-chamber ICD recipients fulfilled an indication for dual-chamber pacing.

After adjusting for various factors, dual-chamber ICD selection was associated with 40% greater odds of a periprocedural complication and 45% greater odds of mortality compared with single-chamber device selection.

“In light of this apparent increased risk, the strategy of routine implantation of dual chamber devices in candidates for ICD therapy without bradycardia pacing indications should be reevaluated,” Dr. Varosy told Reuters Health in an email. “Whether selection of dual chamber devices for enhanced arrhythmia discrimination results in clinically-meaningful improvements in hard clinical outcomes that outweigh the risks of an additional lead is unclear.”

“I believe it is completely appropriate to choose a dual-chamber ICD in any patient who would otherwise be a candidate for a dual chamber pacemaker even in the absence of an indication for defibrillator therapy, or in those patients with supraventricular tachycardias not amenable to medical or arrhythmia ablation therapy where the concern for inappropriate shock from the supraventricular arrhythmia is high,” Dr. Varosy said. “It is less clear, especially in light of our findings, whether the benefits of routine implantation of a dual chamber ICD in all patients outweigh the risks in the absence of bradycardia and SVT indications for the addition of an atrial lead.”

“It is possible that upon further study, we may learn that the benefits do outweigh the risks, but I am not aware of studies that currently demonstrate that the routine use of dual chamber devices over simpler single chamber devices results in meaningful improvements in hard clinical outcomes (such as mortality or hospitalization),” Dr. Varosy added.

In a related editorial, Dr. Amin Al-Ahmad and Dr. James V. Freeman from Stanford University School of Medicine, Stanford, California note, “The NCDR ICD Registry will soon be linked to Medicare data, allowing some assessment of long-term outcomes, and re-evaluation of adverse events and mortality for dual versus single-chamber ICDs over a longer time horizon will be an important area for future investigation.”

Finally, in a state-of-the-art paper, Dr. Johannes B. van Rees and colleagues from Leiden University Medical Center, Leiden, The Netherlands use a review of the literature to detail the frequency of implantation-related complications reported in 12 ICD trials and 7 cardiac resynchronization therapy (CRT) trials.

Average in-hospital mortality was 2.7% in ICD trials using both thoracotomy and nonthoracotomy ICDs and 0.3% in CRT trials.

Complications included pneumothorax (0.9% of ICD implantations, 0.9% of CRT implantations), pocket hematoma (2.2% of nonthoracotomy ICD recipients, 2.4% of CRT recipients), and lead dislodgement (1.8% for nonthoracotomy ICDs, 5.9% for CRTs).

Lead dislodgement rates were higher for left ventricular leads (6.8%) than for right atrial (1%) or right ventricular (0.6%) leads. SOURCE: Reuters Health