Two Predictive Models May Help Determine Which Patients Benefit From ICDs

The Seattle Heart Failure Model (SHFM) and Seattle Proportional Risk Model (SPRM) may help physicians decide which patients would benefit from an implantable cardioverter defibrillator (ICD), according to a study published May 22 in the Journal of American College of Cardiology.

Kenneth C. Bilchick, MD, FACC, et al., looked at 98,846 patients with heart failure (HF), 87,914 of whom had ICDs and were enrolled in ACC's ICD Registry. The remaining 10,932 patients did not have an ICD, and were not enrolled in the registry. The study results showed that patients who underwent ICD implantation had a 25 percent lower risk of death over a five-year follow-up period, compared to those who did not. Additionally, the combination of the SHFM and SPRM models effectively predicted patients' survival benefit from ICDs.

By identifying subgroups, the researchers found that 25 percent of patients with ICDs had a 40 percent reduction in mortality during the follow-up period. Another 25 percent of ICD patients did not receive significant survival benefits; these patients were likely to have a 5.7 percent or less predicted annual risk of death and predicted proportion risk of sudden death at 50 percent or less. The remaining 50 percent of patients with ICDs fell somewhere in between in regards to survival benefits.

The authors conclude that "the SHFM provided a highly effective measure of HF outcomes, whereas the SPRM provided a powerful measure of the proportional risk of sudden death."

"Considering the large amount of time and expense presently allocated to patients with ICDs for implantation, post-operative care, and subsequent generator changes, application of these models could more effectively allocate the health care resources and personalize device therapy for the benefit of patients and society," they explain.

Moving forward, the authors conclude that in order to continue to gather data in support of these models, a future trial should analyze low-risk patients characterized by low SHFM and SPRM risk.

In a related editorial comment, Scott D. Solomon, MD, FACC, and Neal A. Chatterjee, MD, state, "By highlighting the need to look beyond absolute risk, Bilchick et al., have offered us an important step forward in sudden death prevention." They explain that "our contemporary 'one size fits all' approach to ICD implantation does not appear to be a clinically or cost effective strategy in sudden death prevention." They conclude that "By broadening the scope of sudden death prevention tools, we could begin to consider more flexible and individualized approaches to risk reduction."


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