Clinical science: Special reports I
Abstract 21838 Irregular heartbeat in pacemaker recipients may clarify stroke risk
Identifying asymptomatic atrial fibrillation (AF) events (called atrial high-rate episodes or AHREs) by documented pacemaker activity may help predict stroke risk and the need for anti-clotting medication to reduce that risk, according to findings from the ASymptomatic atrial fibrillation and Stroke Evaluation in pacemaker patients and the atrial fibrillation Reduction atrial pacing Trial (ASSERT).
The study included 2,582 patients enrolled in 23 countries from December 2004 to September 2008. All participants were receiving a dual-chamber pacemaker and had high blood pressure. Furthermore, 28 percent had diabetes, 15 percent had heart failure and 7 percent had suffered a stroke. Participants' average age was 76 years and 42 percent were female.
Average follow-up was 43 months after enrollment and ended in June 2010. The primary outcome of the study was ischemic stroke or non-central nervous system clot.
The pacemakers detected AHRE in 60 percent of patients; however, when trained physicians reviewed the stored electrograms, just over half of these episodes were true arrhythmias (irregular heartbeat). The combined rate of stroke and clots in blood vessels outside of the central nervous system was 0.72 percent per year.
Although AF is one of the main risk factors for stroke, most episodes are asymptomatic. Researchers designed the study to have an 80 percent chance of detecting a doubling of clot risk. Final results of the study will be presented at the meeting.
Jeff S. Healey, M.D., M.Sc., associate professor, McMaster University, Hamilton, Ontario, Canada; (905) 577-8004; firstname.lastname@example.org.
(Note: Actual presentation time is 9 a.m., CT, Monday, Nov. 15, 2010.)
Abstract 21844 Disparities among patients receiving heart procedures persist despite Massachusetts Health Care Reform Act
Despite the 2006 Massachusetts Health Care Reform Act, racial, ethnic, educational and socioeconomic disparities still exist in the invasive treatment of cardiovascular disease, according to a new study.
Increased access to health insurance through the reform act has not yet improved the likelihood of receiving necessary invasive heart procedures for African-Americans, Hispanics and people who are less educated and of lower socioeconomic status, researchers said.
Before the reform act, blacks and Hispanics with ischemic heart disease (related to reduced blood flow to the heart) were less likely than whites or Asians to receive heart bypass surgery, angioplasty or stenting. Two years after the reform act, no decrease in this gap was seen.
Increased education was also associated with a higher likelihood of receiving invasive treatment for reduced blood flow to the heart. The study also demonstrated that after the reform act, blacks were at a decreased risk of in-hospital death following surgery, compared to whites and Asians.
The investigators used demographic and billing information obtained from a state registry of Massachusetts residents 21 to 46 years old who were discharged with a diagnosis of ischemic heart disease. They compared pre-reform data on 62,493 patients (Nov. 1, 2004 to July 31, 2006) to post-health care reform data on 61,725 patients (Dec. 1, 2006 to Sept. 30, 2008).
The Massachusetts Health Care Reform Act provides insurance subsidies based on income, limits under-insurance for Medicaid patients and encourages employer participation in insurance premiums.
Michelle A. Albert, M.D., M.P.H., assistant professor of medicine and associate physician, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston Mass.; (617) 732-5089; email@example.com.
(Note: Actual presentation time is 9:15 a.m., CT, Monday, Nov. 15, 2010.)
Abstract 23023 Combined stress and imaging tests net similar outcomes in women with suspected heart disease
Survival rates are similar between women with suspected heart disease who are initially tested with the stress test known as exercise electrocardiography (ECG) and those tested with a combination of exercise ECG and an imaging test, according to a new study.
Exercise ECG measures the heart's activity during exercise. The imaging test myocardial perfusion SPECT (single photon emission computed tomography, or MPS) uses an injected radioactive substance to measure blood flow in the heart.
In this study, researchers recruited 825 women with suspected heart disease from 44 centers and randomized them to one of the two treatment strategies.
Two years after the initial screening, 98 percent of the exercise ECG group had survived without being hospitalized for heart disease, compared with 97.7 percent of patients screened with ECG and MPS. The percentage of participants correctly diagnosed as healthy was 80 percent among those who underwent exercise ECG alone, compared to 76.9 percent for patients screened with ECG and MPS. But the two tests together detected more cases of heart disease (75 percent) than exercise ECG alone (30.8 percent),
Not surprisingly, the initial costs of ECG and MPS together were higher at $495 versus $154 for exercise ECG alone. Follow-up costs for participants who initially underwent exercise ECG were higher, at $180, than were subsequent costs, which were $145 for those who had both ECG and MPS at the beginning of the study. Overall procedural costs averaged $338 for ECG and $643 for ECG with MPS.
Leslee J. Shaw, Ph.D., professor of medicine, Emory University School of Medicine, Atlanta, Ga.; (404) 518-3021; firstname.lastname@example.org.
(Note: Actual presentation time is 9:30 a.m., CT, Monday, Nov. 15, 2010.)
Abstract 21821 Improved heart health linked to therapy to reduce levels of a specific protein
Therapy to decrease levels of a specific protein in heart failure patients resulted in significantly fewer cardiovascular problems compared to patients receiving standard care, in a new study.
In the ProBNP Outpatient Tailored Chronic Heart Failure Therapy (PROTECT) study, researchers targeted the specific biomarker amino-terminal pro-B type natriuretic peptide, or NT-proBNP. Like other peptides, NT-proBNP comprises strings of amino acids, which together form a short protein released by the heart in situations of stress, such as in heart failure.
Previous studies have linked lower levels of this peptide to better survival among heart failure patients, but it remained unclear whether therapy to lower concentrations of NT-proBNP would result in better outcomes.
During the study, fewer patients receiving therapy to reduce NT-proBNP levels suffered either a worsening of symptoms, hospitalization or cardiovascular death compared to patients receiving standard care (29.3 percent versus 43.4 percent).
Patients in the NT-proBNP group had 58 total events and those in the standard therapy group had 98. Furthermore, those in the NT-proBNP group demonstrated greater improvements in heart function and structure, and also exhibited improved quality-of-life measures compared with those who received standard care.
Investigators at the Massachusetts General Hospital enrolled 151 patients into one of two groups. The first received standard care for heart failure patients and the second received standard care combined with NT-proBNP therapy. Study follow-up continued for one year.
The average age of participants was 63 years, and 87 percent were classified as having severe heart failure.
James Januzzi, M.D., director, Cardiac Intensive Care Unit, Massachusetts General Hospital and associate professor of medicine, Harvard Medical School; Boston, Mass.; (617) 527-6897; email@example.com.
(Note: Actual presentation time is 9:45 a.m., CT, Monday, Nov. 15, 2010.)