Who Should Get an ICD?
Abstract & Commentary
By Michael H. Crawford, MD, Editor
Source: Dewland TA, et al. Consideration of patient age and life expectancy in implantable cardioverter-defibrillator referral. Am Heart J 2013;166: 164-170.
The relationship between patients' prognosis and age in decisions regarding implantable cardioverter-defibrillator (ICD) therapy in the primary prevention of sudden death in heart failure patients is poorly understood and not addressed in randomized device trials. Thus, Dewland and colleagues created a survey that was sent to 3000 randomly selected primary care physicians and general cardiologists nationwide. The survey contained questions directed at primary prevention ICD guidelines and this report focused on patient age and life expectancy. The survey was completed by 65% of those selected. An upper age cutoff was reported by 27%, most of whom were cardiologists, and it averaged 84 ± 6 years. Life expectancy was a determinant for 77% of the respondents and they were least likely to be family practitioners. The median life expectancy selected was 2 years (range 1-5 years), but in 13% it was < 1 year. The authors concluded that about 25% of referring physicians use an upper age cutoff for ICD referral and some refer patients with an estimated life expectancy of < 1 year.
ICD implantation guidelines clearly state that only patients with an estimated life expectancy of > 1 year should be considered and age per se is not an exclusion. The results of this survey of referring physicians demonstrates that a significant proportion do not consider life expectancy and use an upper age cutoff. These results could equate to both over and underuse of ICDs for primary prevention of sudden death.
Because clinical trials usually include a paucity of the very old, it is understandable why physicians may have a sense of an upper age cutoff for these devices. However, meta-analyses of the trials have not demonstrated an age above which an ICD is no longer beneficial. In fact, since sudden death is more common the older one is, the benefits are actually greater in older patients. Thus, the guidelines do not specify an age cutoff.
This report also underscores a lack of understanding among referring physicians of the importance of life expectancy in the ICD referral decision. About 25% did not consider this variable and only about half used the > 1 year cutoff. This is very important to avoid the appearance of overuse of ICDs and one cannot expect the electrophysiology (EP) physician to be the best judge of this. The general physician taking care of the patients should have a much better handle on the patients' overall prognosis due not only to their heart failure, but also to other comorbidities and their frailty. The use of a higher life expectancy cutoff (e.g., 2-5 years) is not supported by the trial data since sudden death rates decreased significantly in < 2 years. Thus, it is important that primary care and general cardiology physicians understand the indications for ICD placement for the primary prevention of sudden death. Finally, this study emphasized the need for more communication between referring and EP physicians so that the most appropriate patients are selected for this expensive, yet highly effective therapy.
The Table below lists the major class I indications for an ICD, with the caveats that the patient has an estimated survival of > 1 year with good functional status on optimal medical therapy, which may include revascularization where appropriate.
Table. Major Class I Indications for an ICD
Source: ACC/AHA/ESC Guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. J Am Coll Cardiol 2006;48:e247-e346.