Injecting a platelet inhibitor directly into the heart through a coronary artery (intracoronary) may restore blood flow more effectively than conventional administration through a vein (intravenous) after a severe heart attack, according to new research.
The glycoprotein IIb/IIIa inhibitor abciximab, a potent platelet inhibitor used while treating ST-elevation myocardial infarction (STEMI), helps improve blood flow to the affected part of the heart. Several small studies have suggested that patient outcomes are improved when the platelet inhibitor is administered directly into the heart versus intravenously.
In the Comparison of Intracoronary Versus Intravenous Abciximab in ST-segment Elevation Myocardial Infarction (CICERO) trial, researchers randomized 534 STEMI patients undergoing primary percutaneous coronary intervention (PCI) within 12 hours of chest pain onset to either intracoronary or intravenous administration of abciximab. Their primary endpoint was the rate of successful restoration of blood flow, as measured by electrocardiography. The secondary endpoint measured it with an angiographic marker.
When measured by an electrocardiogram, the rate of successful restored blood flow was not significantly improved in the intracoronary group (64 percent) compared to the intravenous group (62 percent). However, when using an angiographic marker, patients receiving intracoronary administration had a significantly higher rate of successful restored blood flow than in the intravenous group (76 percent versus 67 percent). This marker strongly correlates with clinical outcome, researchers said.
More data is needed to confirm whether intracoronary is more effective than intravenous administration, and to explain the discrepancy between the angiographic and electrocardiographic markers of myocardial reperfusion, researchers said.
Youlan Gu, M.D., University Medical Center Groningen, University of Groningen, Groningen, Netherlands; (011) 1503613485; y.l.gu@thorax.umcg.nl.
(Note: Actual presentation time is 3:45 p.m., CT, Monday, Nov. 15, 2010.)
Abstract 21757 – Erythropoietin doesn't reduce, may increase heart attack muscle damage in older patients
Erythropoietin did not reduce the amount of heart damage in patients who had successful treatment of their heart attack and may increase the amount of heart muscle damage among patients over the age 70, according to researchers in the Reduction of Infarct Expansion and Ventricular Remodeling With Erythropoietin After Large Myocardial Infarction (REVEAL) trial.
Erythropoietin, a drug that treats low blood counts in dialysis patients, has reduced the amount of heart damage after a heart attack in animal studies.
In this study, researchers randomly assigned patients to receive intravenous erythropoietin or a placebo after successful treatment of their heart attack. The patients underwent an MRI scan two to six days later to evaluate the size of the heart damage.
Researchers found that erythropoietin didn't reduce the amount of heart damage compared with placebo. In patients older than 70 years, the area of heart damage was bigger in those patients who received the erythropoietin.
The results suggest that the effect of erythropoietin in animal studies may not be applicable to humans with heart attacks, researchers said.
Sunil V. Rao M.D., Duke University Medical Center, Durham, N.C.; (919) 684-8518; sunil.rao@duke.edu.
(Note: Actual presentation time is 4 p.m., CT, Monday, Nov. 15, 2010.)
Abstract 21842 – Measuring clotting function can help reduce wait for clopidogrel-treated patients undergoing coronary bypass surgery
Using thrombelastography (TEG) to test blood clotting function could mean a shorter wait time for coronary bypass surgery in patients treated with clopidogrel, according to initial findings from the Time Based Strategy to Reduce Clopidogrel Associated Bleeding Related to Coronary Artery Bypass Graft (TARGET-CABG) study.
Current recommendations call for withholding clopidogrel (anti-clotting) therapy for at least five days in patients about to undergo bypass surgery to reduce the chances of excessive bleeding. Researchers say that wait time could be reduced based on these new findings.
In the study, 140 men and women between 18 and 85 years old requiring coronary artery bypass surgery were divided into two groups – one undergoing clopidogrel therapy, the other not using clopidogrel.
Using TEG, researchers determined when it appeared safe to send the clopidogrel-treated patients to surgery, often much sooner than the guideline recommended waiting period.
They found that patients on clopidogrel didn't experience increased bleeding rates and had similar blood transfusions as patients not on the medication.
In clopidogrel-treated patients requiring bypass surgery, bleeding can be effectively reduced by measuring platelet function with TEG to determine when it's safe to operate, researchers found. Patients who have low response to clopidogrel don't need to wait for five days as recommended.
These findings may significantly reduce costs associated with blood product usage and length of hospital admission, researchers said.
Paul A. Gurbel, M.D., director of the Sinai Center for Thrombosis Research, Sinai Hospital, Baltimore, Md.; (410) 601-9600; pgurbel@lifebridgehealth.org.
(Note: Actual presentation time is 4:15 p.m., CT, Monday, Nov. 15, 2010.)
Abstract 21827 – Individualizing antiplatelet therapy for CAD patients may help prevent heart attack, stroke
Determining which coronary artery disease (CAD) patients are at high risk for blood clots may give doctors insight needed to change or intensify their antiplatelet (anti-clotting) treatment, according to new research from the Aspirin Non-responsiveness and Clopidogrel Endpoint Trial (ASCET) study.
Antiplatelet therapy helps prevent blood clotting in the arteries that can lead to heart attack and stroke. However, patients with CAD on a single antiplatelet therapy — aspirin or clopidogrel — still have considerable risk for these types of events. Research suggests that the reason could be aspirin non-responsiveness.
In ASCET, researchers investigated whether aspirin non-responsiveness in CAD patients would lead to increased blood clots when compared to aspirin responsive patients. They tested 1001 stable CAD patients on single aspirin treatment for aspirin non-responsiveness, then randomized them to either continue aspirin (160 mg/day) or clopidogrel (75 mg/day) for at least two years. The researchers recorded incidences of death, heart attack, stroke and unstable angina.
While data on clinical endpoints won't be ready until the meeting, initial results show that 26 percent of the patients were non-responders to aspirin. The trial could contribute to the understanding of how to tailor and individualize antiplatelet therapy in the future.
Alf-Aage R. Pettersen, M.D., Oslo University Hospital, Ullevaal, Oslo, Norway; (011) 47 22119100; alfaage@online.no.
(Note: Actual presentation time is 4:30 p.m., CT, Monday, Nov. 15, 2010.)
Abstract 21785 – Less invasive alternative to heart valve replacement improves quality of life for some patients
A relatively new procedure – transcatheter aortic valve implantation – can improve quality of life for patients too sick to undergo traditional aortic valve surgery, according to new analysis of the Placement of AoRTic TraNscathetER Valve Trial (PARTNER).
Transcatheter aortic valve implantation (TAVI) was recently developed as a less-invasive alternative to traditional valve replacement surgery for patients with a severely narrowed aortic valve (aortic stenosis).
In prior research, TAVI led to a significant improvement in survival at one-year among patients who were not candidates for valve replacement surgery, when compared to medical therapy.
In this study, researchers evaluated the extent to which patients' quality of life improved with TAVI. They reviewed follow-up quality of life assessments at one, six and 12 months for 358 patients with severe aortic stenosis who were not candidates for surgery and were randomly assigned to either TAVI or continued standard therapy.
At the start of the study, quality of life was markedly impaired for both treatment groups, including substantial reductions in the ability to perform physical activities and frequent symptoms, such as marked fatigue and breathlessness. Both patient groups improved over time, but the degree of improvement was much greater among the patients treated with TAVI. The benefits of TAVI on quality of life were largely sustained or increased at six and 12 months.
The degree of benefit with TAVI was striking, corresponding to an average two-level improvement (on a four-point scale) in symptoms related to heart failure, researchers said. The TAVI group also reported a significant improvement in physical abilities, comparable to about a 10-year reduction in age.
David J. Cohen, M.D., M.Sc., director of cardiovascular research, Saint Luke's Mid America Heart and Vascular Institute, Kansas City, Mo.; (816)-932-4581; dcohen@saint-lukes.org.
(Note: Actual presentation time is 4:45 p.m., CT, Monday, Nov. 15, 2010.)
Source: American Heart Association