BOSTON—While implantable-cardioverter defibrillator (ICD) utilization is improving, some subsets of patients still see underuse, said Sana M. Al-Khatib, MD, MHS, of the Duke Clinical Research Institute in Durham, N.C., during a presentation May 9 at the 33rd annual scientifc sessions of the Heart Rhythm Society. She added that more research and education could help to close this gap.

“ICD therapy has been shown in randomized controlled trials [RCTs] to improve the survival of patients with chronic systolic heart failure [HF],” Al-Khatib said. “Strong evidence has led the ACC/AHA [American College of Cardiology and American Heart Association] task force to designate ICD therapy as a Class I indication for heart failure.”

However, despite abundant evidence from multiple RCT ICD trials, ICDs continue to be underutilized in practice, Al-Khatib offered.

Al-Khatib referenced the ADVANCENT database, which found that 41 percent of all eligible white patients and 30 percent of all eligible black patients had an ICD [Am J Cardiol 2007; 100:924-929]. These results alone pinpoint the disparities within the field of ICD implantation.

Additionally, when Curtis et al looked at sex differences of ICD implants in 2007, they found that men were three times more likely than women to receive an ICD for primary prevention when indicated.

Al-Khatib and colleagues wanted to dig deeper into this issue by analyzing AHA’s Get with the Guidelines-Heart Failure database to better understand whether there were sex or racial differences in ICD implantations.

Of 13,034 patients analyzed, 35 percent had an ICD in place or a planned ICD. When the researchers looked at patient subsets they found that black men were 27 percent less likely to receive ICDs and black women were 44 percent less likely to receive the life-saving therapy.

“We then looked carefully for the potential reasons for these disparities,” she said.

Al-Khatib et al also surveyed ACC members who are practicing cardiologists in the U.S. to better understand the reasons for these disparities. The cardiologists were presented with different case scenarios of patients implanted with ICDs in terms of gender, race, and age to see whether these factors had an impact in ICD implantation.

“Based on these responses these physicians did not seem to be less likely to offer a primary ICD to older patients but we did find differences between races,” she said.

 Al-Khatib offered the following reasons for the underuse:

• Concerns over safety of the ICD fueled by several device and lead recalls in the past decade;
• Concerns about the safety of the procedure;
• Skepticism about the durability of the beneficial effect of ICD therapy beyond the limited follow-up period of clinical trials;
• Skepticism about the applicability of RCT results to patients seen in practice and to racial minorities;
• Dissatisfaction with the high rate of inappropriate ICD shocks and the potential negative effect that shocks may have on survival and quality of life;
• Difficulty identifying patients, mostly driven by the absence of an EMR in many clinical practices;
• The perceived need for better tools to risk stratify patients for sudden cardiac death (SCD); and
• Cost and cost-effectiveness.

“The risk of SCD is lower in women so statistically you need more women to prove the efficacy of ICD in women,” Al-Khatib offered. “I don’t think we can really derive any conclusions about ICDs not being effective in certain subgroups of patients.”

She added that people should use caution when attempting to dissect results of clinical trials that look at subgroup analyses and meta-analyses to conclude that ICD therapy is not beneficial in these subgroups, particularly those who may not be well represented in clinical trials.

Additionally, Al-Khatib said that perhaps what is needed is to better educate the patient about the risks of SCD and the role of the ICD. At Duke, researchers are experimenting with an initiative that includes a video intervention designed to increase patient knowledge and decrease “decision conflict.” Al-Khatib said that the hope is that the video project will help lead more patients to choose ICD therapy and help reduce the disparities within ICD usage.

While the rate of primary prevention ICD utilization increased between 2005 and 2009, including for black women, white women, black men and white men, Al-Khatib said that these rates still need improvement.

“In these data we saw that each subpopulation of patients improved in terms of ICD implantation; however, we still observed disparities,” Al-Khatib said. The key question that remains is: why do these disparities still exist?  

She noted a significant improvement in the primary prevention of ICDs in black men that is approaching the utilization rates of white men. But she said that while these gaps are closing, some subsets such as women still lag behind.

The solution may lie in education, Al-Khatib said. Future improvements will come from improved patient and physician education. Additionally, she said future research will significantly help to close these racial and gender gaps and improve patterns of ICD use.

“ICD therapy saves lives, but it is clearly underutilized in many potentially eligible patients,” Al-Khatib said. “Although utilization and racial disparities have improved, we should strive to continue to improve.”

In terms of the future of ICD research, Al-Khatib quoted Sir Winston Churchill: “Now this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning.”