Medical Device Daily National Editor
Should a consultation with a cardiologist be a matter of promoting what is considered the best, state-of-the-art technology, or simply the presentation of facts — not just the benefits for some, but the risks, near-term and longer-term, for many?
A new study just posted on the website of the German Cardiac Society (Düsseldorf, Germany), suggests that the benefits of implantable cardioverter defibrillator (ICD) technology are being oversold to patients and thus the devices over-used.
Following an analysis of the various drawbacks of ICDs – including not really extending the lives of heart patients to any significant degree – the study concludes: "It is ethically imperative that we are honest with the data, so that we can be honest with our patients. A reappraisal of the benefits and potential hazards of ICD therapy will enable physicians to a have a more mutually informed and balanced dialogue with their patients."
The study says that while the shocks provided by ICDs are capable of preventing death as the result of a sudden arrhythmic disturbance, the heavy cost of the devices is not supported by the amount of additional years provided to patients.
It says that an ICD "only modestly prolongs life" and costs from 125,000 to 150,000 per year "for one to four years of additional life" and that the added years of life may come with "potential adverse effects on morbidity and quality of life."
Additionally, the authors note that "most patients" implanted with the devices never receive a "therapeutic" shock but are "exposed to ... inappropriate discharges and device failure."
The life-saving ability of the devices is duly noted by the study, citing studies showing a reduction of mortality of up to 20% reduction in "all-cause" mortality in a population of patients with New York Heart Association Class II or III symptoms and reductions of from 46% to 54% reduction in sudden death, this latter figure in "observational studies."
The authors qualify the results of the observation studies, however, by noting that the reduced rate of sudden death in these may have been the result of choosing healthier patients for implantation.
While acknowledging the efficacy of ICDs to shock and save lives, the bulk of the study focuses on two types of problems reducing the benefits of their use and potentially reducing a patient's quality of life. These problems are:
• what was referred to in the report as "mechanical complications," such as device malfunctions, lead problems and site infections, during the hospital stay in which the implant was made and then post-implant complications;
• inappropriate shocks – described as "surprisingly high" – 19.1 per 100 patient years in randomized clinical trials and 4.9 per 100 patient years in observational studies.
The report says that the shocks "are commonly due to double counting, over-sensing, ectopy, and supraventricular tachycardias, ranging from sinus tachycardia to atrial fibrillation."
These inappropriate shocks increase morbidity, the study says, because they "have consistently been demonstrated to reduce overall quality of life and increase the incidence of depression and anxiety while obligating strict driving restrictions."
In addition to morbidity, these unnecessary shocks, "may have attendant lethal risks as patients receiving inappropriate shocks in the SCD-HeFT study were at higher risk for death (HR: 1.97) as well those in the MADIT II (HR: 2.29). The insertion of the device may be directly or indirectly proarrhythmic."
"Arrhythmogenesis," the study says, may be promoted by "device malfunction, induction of arrhythmias from inappropriate shocks, pacemaker-facilitated triggers and reversal of activation wavefronts from epicardial resynchronization increasing dispersion of refractoriness. Additionally, local lead effects with mechanical irritation and late fibrosis may be a potential mechanism for VT [ventricular tachyaarhythmias]." Also referred to are problems concerning implant leads that have recently been seen in some devices, and prompting recalls.
The report cites the "long-term reliability of ICD leads, referencing a study that found a 15% failure rate in leads during follow-up.
"The estimated lead survival rates at five and eight years after implantation were 85% and 60%, respectively. The annual failure rate increased progressively with time after implantation and reached 20% in 10-year-old leads (P<0.001). The major lead complications were insulation defects (56%), lead fractures (12%), loss of ventricular capture (11%), abnormal lead impedance (10%), and sensing failure (10%)."
Of interest, lead "defects" were more common in patients who were younger and "more often female," raising, the report said, "important issues for patients with expected longer life span at time of ICD implantation, such as younger patients, patients with preserved left ventricular function, or patients who have a prophylactic ICD."
And it goes on to say that mechanical problems – primarily hardware and programming malfunctions — with ICDs continue despite advances in design and manufacturing, these problems having "tremendous adverse effects on patient morbidity, both medically and psychologically." And it cites sudden deaths, though "rare," with high-voltage lead failures and pulse generator failures.
As an umbrella comment, the report authors compare ICD implantation to "an insurance policy" which may not benefit, but could harm, those not requiring shocks.
And it says that practice guidelines for implanting these devices has been driven by the "entry criterion of the trials ... not the group actually studied."
It concludes: "This liberal cutoff may be a movement in the wrong direction, as the average EFs [ejection fractions] were substantially lower than the inclusion cutoffs."
For instance: "In SCD-HeFT, the patients with an EF between 30% and 35% had no benefit from ICD which was restricted only to those with an EF<30%." And "most of the trials had peculiar inclusion criteria that were not considered in the recommendations of the guidelines.
The result of these differences, the study says, is that most patients receiving an ICD implant "never receive a therapeutic discharge but are exposed to the risks of ICDs . . . . Three-quarters to two-thirds of ICD recipients in the observational studies received no therapeutic ICD discharges, and only 5% to 12% of trial participants received an appropriate shock per year.
The report concludes that while ICD shocks may be considered "appropriate," this does not mean that they are "necessary" and that a better distinction needs to be made between this.
Overall, the report's conclusions underline considerable current research indicating that the identification of patients most requiring ICDs is inexact and that there is a clear need for a better diagnostic to determine those at highest risk for sudden death from an arrhythmia.
And the overall report underlines the general increased emphasis, both in the U.S. and in Europe, on using a cost-benefit analysis to determine appropriate therapy, particularly against the background of increasing technology costs for healthcare.