According to a new UCLA-led study, the treatment of the most common form of heart attack (myocardial infarction) over the past decade have resulted in higher survival rates for men and women regardless of age, race, or ethnicity. However, the study also notes that there is room for improvement regarding how current treatment guidelines are applied to specific patient groups. The findings are published in the current online edition of the Journal of the American Heart Association.
For the study, the investigators analyzed records for 6.5 million individuals who were treated for heart attacks from 2002 through 2011. The review was among the first and largest national studies to assess the impact of the trend toward more aggressive care for patients who experience the type of heart attack known as non-ST elevation myocardial infarction (NSTEMI).
“The substantial reductions in in-hospital mortality observed for NSTEMI patients nationwide over the last decade reflect greater adherence to evidence-based, guideline-directed therapies,” explained senior author Dr. Gregg C. Fonarow, UCLA’s Eliot Corday Professor of Cardiovascular Medicine and Science as well as the director of the Ahmanson–UCLA Cardiomyopathy Center at the David Geffen School of Medicine at UCLA. He added, “Nevertheless, there may be further opportunities to improve care and outcomes for patients with NSTEMI, who represent the greater proportion of patients presenting with myocardial infarction.”
Myocardial infarctions are roughly classified into two types. The more severe form, ST-elevation myocardial infarction (STEMI), involves complete blockage of an artery supplying blood to the heart muscle. The less severe type, NSTEMI, involves partial or temporary blockage of the artery. Studies in the United States and Europe have reported that although the incidence of STEMI heart attacks is declining, the number of NSTEMI heart attacks increased in the past decade.
The guidelines issued in 2012 by the American College of Cardiology and American Heart Association recommended initiating cardiac catheterization in high-risk NSTEMI patients within 12 to 24 hours after the patient arrives at the hospital. Since 2009, this strategy has been evolving due to the publication of the Timing of Intervention in Acute Coronary Syndromes trial. Previously, the recommendation was to begin catheterization in high-risk NSTEMI patients within 48 hours. The research team evaluated trends in the use of cardiac catheterization for individuals who had been hospitalized after suffering an NSTEMI, within 24 hours and within 48 hours of hospital presentation; this was done to determine whether changes in their care may have resulted in better outcomes.
The researchers analyzed publicly available records from the Nationwide Inpatient Sample, which is the largest US database of hospitalized patients. Of the 6.5 million patients whose records they reviewed, 3.98 million were admitted to hospitals with NSTEMI diagnoses. The investigators tracked the proportion of those patients who underwent cardiac catheterization each year, and their outcomes; they determined how many died in the hospital, the average length of their hospital stays, and the cost of hospitalization. They found that as the trend toward earlier intervention in NSTEMI patients took hold, with physicians beginning treatment within 24 hours after the patients arrived at the hospital, rather than within 48 hours, the rate of in-hospital death declined from 5.5% in 2002 to 3.9% in 2011. Improvements were found for men and women, older and younger patients, and across all races and ethnic groups. Furthermore, the average length of patients’ hospital stays decreased during the decade-long study, from 5.7 days to 4.8 days. NSTEMI patients who underwent a cardiac catheterization within the first 24 hours were found to have the shortest average stays.
As the study progressed, more NSTEMI patients in all demographic groups received early cardiac catheterization; however, there were still significant differences across age, gender, and racial, and ethnic groups in how frequently early intervention was used. For example, men were more likely to receive earlier catheterization than women.
“Despite the improvement, there are significant differences in the age-, gender-, and ethnicity-specific trends in the use of invasive management of NSTEMI, and these findings may help guide further improvements in care and outcomes for male and female patients of all ages, races and ethnicities,” explained the study’s first author, New York Medical College’s Dr. Sahil Khera. He added, “Further efforts are needed to enhance the quality of care for patients with NSTEMI and to develop strategies to ensure more equitable care for patients with this type of heart attack.”