Almost one-fourth of the patients enrolled in a national registry who received implantable cardioverter defibrillators in recent years did not meet evidence-based criteria for implantation, according to a report in the Jan. 5 issue of JAMA.
The patients who did not meet these criteria were at significantly increased risk for complications, including death, cardiac tamponade, pneumothorax, infection, and hematoma. The study data suggest that one excess complication developed for every 121 non–evidence-based ICD implantations that occurred.
It is important to note that "these complications resulted from procedures that were not clearly indicated in the first place. While a small risk of complications is acceptable when a procedure has been shown to improve outcomes, no risk is acceptable if a procedure has no demonstrated benefit," said Dr. Sana M. Al-Khatib of Duke Clinical Research Institute, Durham, N.C., and her associates.
The investigators performed what they described as the first national study to examine in-hospital outcomes of patients receiving a non–evidence-based ICD because such outcomes have not been known until now. Even physician adherence to the guidelines in routine clinical practice has not been clear.
Four recommendations in the practice guidelines were of particular concern: ICDs are not indicated in the acute phase after MI, after recent coronary revascularization, in patients with New York Heart Association class IV symptoms, or in those with recently diagnosed heart failure. No benefit with ICD implantation has been demonstrated in these groups, while potential harm is clear.
Dr. Al-Khatib and her colleagues analyzed data on 111,707 implantations done at 1,227 medical centers in 2006-2009 for primary prevention among adults with cardiomyopathy, using the National Cardiovascular Data Registry’s ICD registry. The registry tracks ICD implantations in all Medicare beneficiaries as well as in non-Medicare patients treated at 78% of the 1,448 hospitals enrolled.
They found that 25,145 (22.5%) of the procedures were performed in patients who did not meet evidence-based criteria.
A total of 9,257 ICDs (37% of those implanted contrary to recommendations) were implanted within 40 days of an MI, 814 (3%) were implanted within 3 months of coronary artery bypass graft (CABG) surgery, 3,022 (12%) were implanted in patients with NYHA class IV symptoms, and 15,604 (62%) were implanted in patients newly diagnosed as having heart failure. Because some patients had more than one non–evidence-based criteria, the figures exceed 100%.
Complications were significantly more likely to arise in patients who did not conform to evidence-based criteria for the devices (3.2%) than in those who did (2.4%). In particular, the risk of in-hospital death was 0.57% for patients in whom ICDs were not indicated, significantly higher than the 0.18% risk in patients for whom they were indicated. The median length of hospital stay also was significantly longer (3 days vs. 1 day).
There was no clustering of non–evidence-based implantations at a subset of medical centers, although the distribution of such procedures varied greatly. At many centers, these "nonindicated" implantations comprised more than 40% of the total number performed there. This finding suggests that both hospital sites and individual physicians need to improve adherence to implantation guidelines, Dr. Al-Khatib and her associates said (JAMA 2010;305:43-9).
The number of non–evidence-based implantations also varied by physician specialty.
Electrophysiologists were significantly less likely than were other specialists to implant ICDs in patients in whom the devices were not indicated, with a rate of 21%. The rate for nonelectrophysiologist cardiologists was 25%, that for thoracic surgeons was 36%, and that for general surgeons or other physicians was 25%.
"Future research should investigate [the] reasons behind this disparity [among specialties] and propose ways to decrease non–evidence-based ICD implants," the investigators added.
They noted that some of the "nonindicated" ICD implantations may well have been clinically appropriate, since there are some circumstances in which deviations from the guidelines are allowed. "The guidelines clarify that the ultimate judgment regarding care of a particular patient must be made by the physician and the patient in light of all of the circumstances presented by that patient," Dr. Al-Khatib and her colleagues concluded.
The study was funded by the National Heart, Lung, and Blood Institute. Dr. Al-Khatib reported receiving support from Medtronic and Biotronik, and her associates reported ties to numerous drug and device manufacturers.