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Analyzing Preventive CRT in the Elderly
Posted By Physicians Weekly On July 26, 2012 @ 10:58 am In Articles,Cardiology,Primary Care,Recent Features,Slider,Surgery | No Comments
Published studies have shown that the prevalence of congestive heart failure (CHF) increases as people age, rising from 2% to 3% in the total population to 10% to 20% after patients reach age 75. When compared with younger patients, CHF in the elderly has been associated with higher mortality rates. “Even when medical management is optimized, elderly patients with CHF still require frequent healthcare utilization, including those with the early stages of disease,” says David T. Huang, MD. “While medical therapy can sometimes help, there are concerns about disease recurrence.”
Cardiac resynchronization therapy (CRT) can be used in conjunction with implantable cardioverter defibrillators (ICDs), an approach that has been shown to reduce hospitalizations and mortality relative to CHF. “CRT and ICDs have become important components for qualified patients with class III or IV heart failure,” adds Dr. Huang. “CRT has been used in patients of many age ranges in the past, but mostly in the most severe late-stage cases. Symptoms can improve with this therapy, but questions have been raised about whether or not CRT should be used in earlier stages of CHF in order to better prevent symptoms.”
When patients with CHF are properly selected, age should not be used as a sole discriminator to exclude device therapy.
The Multicenter Automatic Defibrillator Implantation Trial with CRT (MADIT-CRT) recently found that CRT utilizing defibrillators (CRT-D) was associated with a 34% reduction in the risk of heart failure or death when compared with ICD-only therapy in asymptomatic or mildly symptomatic patients. However, limited data are available on the benefits and complications of using preventive CRT-D therapy in older age groups.
In the August 2011 Journal of Cardiovascular Electrophysiology, Dr. Huang and colleagues conducted a study to evaluate the effect of age on outcomes in the MADIT-CRT trial. “Our study showed that CRT-D reduced the number of exacerbations associated with CHF when compared with ICD-only therapy,” says Dr. Huang (Table 1) . “In patients aged 75 and older, CRT-D dramatically reduced the primary endpoints of CHF or death. These clinical response rates were similar for patients aged 60 to 74.” Dr. Huang added that risk reduction with CRT-D therapy was less pronounced in patients younger than 60, possibly because of lower event rates in this patient subset.
The investigation by Dr. Huang and colleagues also revealed that there was no evidence of increased adverse events relating to CRT-D in patients aged 75 and older when compared with younger patients (Table 2) . There was no significant difference in the rate of device-related adverse events within 90 days following CRT-D implantation among age-subgroups.
“Elderly patients differ substantially from younger individuals with CHF, even at early stages of the disease,” explains Dr. Huang. “The elderly are more likely to have comorbidities. These can lead to increased rates of overall medical resource utilization, urgent care visits, hospitalization, and mortality. The increasing prevalence of heart failure, in conjunction with age-associated differences relating to CHF, underscore the need to further evaluate efficacy and safety of CRT in various age groups.” He notes that the MADIT-CRT trial was designed with no upper age limit as an exclusion criterion. This facilitated the analysis of younger and older aged group outcomes in the Journal of Cardiovascular Electrophysiology study.
There is currently ongoing debate about whether or not older patients should endure CRT procedures because of their invasiveness, Dr. Huang says. “Our study suggests that there is a benefit, but it’s important to remember that patients from the MADIT-CRT trial were carefully selected. These individuals had few comorbidities and may not reflect ‘real-world’ elderly patients. Proper selection of appropriate patients for any device therapy is always warranted. When patients with CHF are properly selected, age should not be used as a sole discriminator to exclude device therapy.”
Dr. Huang’s study team plans to reassess findings from their investigation to further explore the use of CRT-D in younger patients who experienced little or no change in the primary endpoint. “The lack of statistically significant results in these individuals may be explained in part by their overall low clinical risk with ICD-only therapy during the MADIT-CRT trial period. With longer term follow-up, it’s possible that CRT-D will be associated with a significant clinical benefit in these younger patients too. Meanwhile, it behooves us to continue striving to improve and optimize techniques and to reduce implant times for patients being considered for CRT-D. As these enhancements come, there is hope that we can further reduce the risk of adverse events and complications for these patients.”
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 (Table 2): http://www.physiciansweekly.com/wp-content/uploads/2012/07/Huang-table-2.png
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