Medical Device Daily Associate

The fact that a medical technology has been in use for a long time does not mean that all the important clinical questions about its use have been completely resolved.

The clinical use of cardiac pacemakers is a case in point. When ECRI (Plymouth Meeting, Pennsylvania), an independent health services research agency, surveyed its U.S. hospital subscribers regarding their use of single- and dual-chamber pacemakers, it said that the results were unexpected.

Based on the results of that survey, the organization compiled an evidence report indicating that while dual-chamber devices were clinically superior to their single-chamber counterparts, more research needs to be done in order to make a definitive argument for their use in all cases.

ECRI – formerly known as the Emergency Care Research Institute – is a nonprofit health services research agency. Its mission is to improve the safety, quality and cost-effectiveness of healthcare.

ECRI’s focus is healthcare technology, healthcare risk and quality management, and healthcare environmental management. It provides information services and technical assistance to more than 5,000 hospitals, healthcare organizations, ministries of health, government and planning agencies, voluntary sector organizations, associations and accrediting agencies worldwide.

Its services are designed to alert readers to technology-related hazards; disseminate the results of medical product evaluations and technology assessments; provide expert advice on technology acquisitions, staffing, and management; report on hazardous materials management policy and practices; and supply information on risk control in healthcare facilities and clinical practice guidelines and standards.

According to ECRI spokesperson Lindsay Ehlers Cox, the organization’s clients include subscriber healthcare facilities and government agencies that make important policy and coverage decisions such as the Centers for Medicare & Medicaid Services (CMS; Baltimore)

“We’re kind of looked at as the independent organization that doesn’t use opinion in any of our judgments on things,” she told Medical Device Daily. She added that her organization evaluates “tons of devices and procedures and drugs” each year.

This latest survey showed that the pacemaker type that hospitals implanted (single or dual) varied for reasons that seemed unrelated to patient indications or clinical characteristics.

Ehlers Cox said ECRI surveyed a sampling of its healthcare organization members about a year and half ago, and discovered some interesting results that spurred the initiation of the report. “We found that some of the things that we had thought about their pacemaker usage were completely off.”

For example, she said, ECRI expected to find that teaching hospitals, which typically treat more complicated cases, implanted more dual-chamber pacemakers than community hospitals did in their patients. However, survey results showed that a higher number of implants in the teaching hospitals were of single-chamber models.

These unexpected findings, coupled with ongoing questions from hospitals about which pacemakers to use, led the agency to conduct a systematic review of published evidence on pacemakers to ascertain which type of pacemaker to use in order to achieve the best patient outcomes.

ECRI published its systematic review last month as a Windows on Medical Technology evidence report titled “Dual-Chamber vs. Single-Chamber Pacemakers for Sinus Node Dysfunction and Atrioventricular Block.”

Each year, about half a million Americans receive pacemaker implants to regulate abnormally slow or fast heartbeat. These electronic devices are mostly used to treat abnormally slow heartbeat rhythms, or bradycardias, which, if untreated, cause symptoms such as fatigue, weakness, dizziness, fainting and sometimes death.

Bradycardias most often are caused by sinus node dysfunction (SND) and atrioventricular (AV) block.

Drawing from an evidence base of 32 trials that enrolled more than 5,500 patients with these conditions, ECRI pooled data to perform various meta-analyses. They concluded that dual-chamber pacemakers, which pace both the ventricles (lower chambers) and the atria (upper chambers) of the heart, are more clinically beneficial and cost-effective compared to single-chamber models, which pace only the ventricles.

Specifically, the evidence base for this report comprised five parallel-arm, randomized controlled trials with 5,372 patients and 27 randomized crossover trials with 526 patients.

These two trial designs evaluated different outcomes (the parallel-arm trials evaluated mortality and serious morbidities such as stroke and heart-failure hospitalizations; the crossover trials focused primarily on exercise tolerance and pacemaker syndrome).

Except for functional status and pacemaker syndrome, ECRI said it analyzed parallel-arm trials and crossover trials as two separate bodies of evidence.

Dual-chamber pacemakers range in cost from $7,000 to $10,000, and single-chamber pacemakers range in cost from $5,800 to $9,000. ECRI’s own product comparison of dual-chamber and single-chamber pacemakers with similar features lists the cost of a dual-chamber pacemaker as $700 to $1,500 higher than the cost of a comparable model of single-chamber pacemaker from the same manufacturer.

While the cost of the dual-chamber device is higher, much of the analysis pointed to, albeit not in an overwhelmingly statistically significant way, the benefits of such a system over its single-chamber cousin.

Analysts found that dual-chamber pacing reduces symptoms of pacemaker syndrome, which causes dizziness and fatigue when the pacemaker attempts to pump against a closed valve.

The report also found that dual-chamber pacing led to a lower risk of stroke than single-chamber ventricular pacing, with a meta-analysis finding that dual-chamber pacing lead to a 25% reduction in the rate of stroke relative to single-chamber ventricular pacing.

Additionally, the report found that dual-chamber pacing leads to lower risks of heart failure hospitalization and atrial fibrillation (AF). The organization’s meta-analysis found that dual-chamber pacing led to a 20% reduction in the rate of heart failure hospitalization relative to single-chamber ventricular pacing and that dual-chamber pacing lead to a 24% reduction in the rate of AF relative to its single-chamber counterpart.

Another interesting conclusion was that dual-chamber pacing lead to a lower combined rate of serious adverse events (mortality, stroke, heart-failure hospitalization) than single-chamber pacing, with the analysis showing a 14% reduction in the combined rate of serious adverse events relative to single-chamber ventricular pacing.

The evidence report also discusses risks and benefits associated with switching patients from single-chamber pacing to dual-chamber pacing. However, analysts found that dual-chamber pacing is not necessarily superior to single-chamber pacing relative to improvement in cardiovascular functional status. Also, some evidence showed that dual-chamber pacemakers had more mechanical problems, although these were generally minor.

ECRI said it recommends that while dual-chamber pacing appears to lead to more clinically significant benefits, that practitioners carefully weigh their options prior to implant, not exactly a ringing endorsement for the exclusive use of dual-chamber devices at this time.

While she said, “in many of the criteria that we had set for this evaluation, the dual chamber prevailed,” Ehlers Cox noted that until there is more conclusive evidence the decision to use either a single- or dual-chamber pacemaker “has to be made on a case-by-case basis.”