ICDs in Older Patients After MI

Journal Wrap | Following a myocardial infarction (MI), only one in 10 patients aged 65 or older with an ejection fraction of 35% or less had an implantable cardioverter-defibrillator (ICD) inserted within 1 year, and, on average, patients who received an ICD had a significantly lower mortality rate than those who did not—15.3 vs. 26.4 events per 100 patient-years, according to a study published June 23 in the Journal of the American Medical Association.

Using data from the ACC’s ACTION Registry-GWTG linked with Medicare data, researchers assessed records from 10,318 patients at 242 hospitals between Jan. 2, 2007, and Sept. 30, 2010. The median age of patients was 78, and the majority (75%) underwent in-hospital revascularization.

Results showed that the cumulative ICD implantation rate within 1 year of the cardiac event was 8.1%, and median time from admission to implantation was 137 days. For patients who had undergone revascularization, the timeframe was 115 days.

Based on their findings, the authors identified patient factors associated with a greater likelihood of ICD implantation within 1 year of the MI: younger, male patients who had prior coronary artery bypass graft procedures, larger infarcts, in-hospital cardiogenic shock, and cardiology follow-up within 2 weeks after hospital discharge. Those patients with a lower likelihood of ICD implantation were older, female, and had end-stage renal disease.

Researchers also found significant variation in hospital ICD implantation rates. After adjusting for differences in the patient mix across hospitals, the study showed that among 242 hospitals, the median estimated 1-year ICD implantation rate was 7.4%. Patients in hospitals in the 90th percentile of 1-year ICD implantation (11.5%) were 2.4-fold more likely to receive an ICD than hospitals in the 10th percentile (4.8%).

The authors conclude that moving forward, “Additional research is needed to determine evidence-based approaches to increase ICD implantation among eligible patients.”

Sean Pokorney, MD, MBA, a cardiology fellow in the Division of Cardiology at Duke University Medical Center, Durham, NC, and the study’s lead author, notes that the study’s findings are surprising and raise “concerns about gaps in care that occur during the transition from inpatient care to outpatient care.” He adds that the study “should raise awareness of the need to be vigilant about identifying patients who are candidates for primary prevention ICDs.”

In an accompanying editorial, Robert G. Hauser, MD, FACC, a cardiologist with the Minneapolis Heart Institute at Abbott Northwestern Hospital, Minneapolis, MN, agrees that it is “concerning that so few potentially ICD-eligible patients are undergoing implantation, especially considering that ICDs significantly improve survival.” He suggests that the reason for the problem is the fragmented health care system in which “overly burdened primary care physicians are expected to connect all the clinical and diagnostic information without the essential tools and necessary facts.”

“Even though the use of ICDs for primary prevention may not seem to make as much sense for an 80-year-old patient as it does for a patient in his or her 50s or 60s,” continues Hauser. “An older patient at risk for sudden cardiac death should have the same opportunity to choose potentially lifesaving therapy. [This study] can help physicians and their patients be better informed during discussions about the risks and benefits of ICDs in older persons.”

Pokorney SD, Miller AL, Chen AY, et al. JAMA. 2015;313(24):2433-40.

More Women Readmitted After MI

A recent study in Circulation has found that women have higher rates of 30-day readmission than men after acute myocardial Infarction (AMI).

Researchers used data from the Health Care Cost and Utilization Project—State Inpatient Dataset of California from January 2007, to November 2009, to evaluate sex differences in the rate, timing and principal diagnosis of 30-day readmission following AMI, and to examine the association of sex with 30-day readmissions, while assessing whether or not these is an age-sex interaction.

A total of 42,518 hospitalizations from 40,851 patients aged 18-65 years with AMI were examined. Women were more likely to be older and African American or Hispanic, and be covered by Medicare or Medicaid. Women also had a higher frequency of unfavorable cardiovascular risk factors and comorbidities compared to men.

The number of patients with at least one readmission for the population was 4,775 (11.2%). The 30-day all-cause readmission rate was higher for women (15.5% vs. 9.7%). The higher rates for women existed regardless of age, race and payer status. There was no difference in the readmission risk between men and women, with both sexes having the highest risk 2-4 days after discharge and declining thereafter. In both women and men, 42% of readmissions occurred in the first week following AMI. Women were more likely to present for readmission with non-cardiac diagnoses.

According to the authors, a large proportion of the association of sex on readmissions was explained by socio-demographic differences. The higher comorbidity burden women faced also added to the vulnerability for readmission. However, the fact that this higher risk existed in women even after adjusting for covariates suggests that there are other factors that predispose younger women to readmission. The authors suggest that these differences may include differences in comorbidities and/or consequences of the AMI, as well as social and/or psychosocial factors.

Researchers also note that women are more prone to complications after hospitalization for AMI. They suggest that women may focus less on their own recovery following AMI due to the work and home roles. As the typical family caregiver, women may not have a caregiver of their own. Additionally, “Women may be more susceptible to the disruption of the hospitalization itself and have more stressful and difficult experiences than man,” the authors said. “This excess allostatic load may lead to greater vulnerability after discharge.”

Moving forward, the authors suggest that “health care providers should be made aware of this disparity, and research efforts be directed toward identifying risk factors or opportunities in care that differ between groups and that may mediate the observed disparities in the risk of readmission, which may inform effective interventions.” They add that “there may need to be a continued focus on safe discharge planning and early ambulatory interventions following hospital discharge,” especially for the high-risk group of young women.

In an ACC.org Journal Scan, Elizabeth A. Jackson, MD, recommends that further research “related to factors associated with readmission among young women may help promote interventions that translate into reduced readmission rates.”

Dreyer RP, Ranasinghe I, Wang Y, et al. Circulation. doi: 10.1161/ CIRCULATIONAHA.114.014776.

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, SCD/Ventricular Arrhythmias

Keywords: CardioSource WorldNews, ACC Publications, American Medical Association, Cardiovascular Diseases, Defibrillators, Implantable, Myocardial Infarction

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