With eight basic medical facts in hand, doctors can now estimate the risk of bleeding for a patient having a heart attack.
Using clinical variables, researchers at the School of Medicine, Duke University and collaborating institutions have created a new method to estimate bleeding risk and help lessen the chances that heart attack patients will experience this common complication.
“Until now, there hasn’t been a simple tool applicable to the general population that can predict the risk of bleeding before patients are treated for heart attack,” said Richard G. Bach, M.D., associate professor of medicine and an author of the study. “Older methods for estimating risk either were derived from a low-bleeding-risk population or used variables that aren’t available until after treatment is begun.”
The assessment tool is described in a study in the April 14 issue of Circulation.
Doctors treat heart attacks with medications and procedures intended to prevent ischemic complications, or damage caused by lack of oxygen to the heart. But these treatments — anticlotting drugs and catheter-based interventions to the heart — also increase the likelihood of bleeding, which can be deadly.
“The risk of bleeding is substantial in people with heart attacks,” said co-author Brian F. Gage, M.D., associate professor of medicine and director of the outpatient Anticoagulation Service. “We found that this population could be risk-stratified, so that people at high risk of bleeding could receive less-aggressive anticoagulant and antiplatelet therapy, while those at low risk could receive full-dose therapy.”
Led by Sumeet Subherwal, M.D., a former Barnes-Jewish Hospital resident and now a cardiology fellow at Duke University, and in collaboration with several investigators, including Karen Alexander, M.D., a Duke Clinical Research Institute cardiologist, the researchers analyzed the medical histories of more than 89,000 patients hospitalized in the United States for non-ST-elevation heart attack. This type of heart attack is the most common and usually results from a partial blockage of the heart’s arteries.
The patient histories were part of the CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines) Quality Improvement Initiative, a national multicenter program that aims to improve outcomes for heart attack patients. The risk-assessment tool is called the CRUSADE bleeding score.
“A lot of treatment decisions have to be made very promptly after the patient arrives,” said Bach, also medical director of the Cardiac Intensive Care Unit at Barnes-Jewish Hospital. “So we designed a bleeding-risk stratification tool that would require only those variables that can be obtained up front. It’s a practical tool that can be used in any hospital setting.”
The CRUSADE analysis identified eight factors that could predict the odds that a heart attack patient might suffer a bleeding event. The factors are gender, heart rate, blood pressure, hematocrit (the concentration of red cells in the blood), creatinine clearance (a measure of kidney function), diabetes, peripheral vascular disease or stroke, and congestive heart failure.
The bleeding score calculation assigns points to each factor so that the total score coincides with risk of bleeding evidenced in the CRUSADE cases. The range of possible scores is divided into five categories from a very low to very high risk of bleeding.
The bleeding risk score is intended to help guide critical early treatment decisions for clinicians caring for heart attack patients, but the impact of its use on outcomes will need to be tested in clinical trials, Bach said. Potentially, the score will be used in conjunction with other practice guidelines to optimize heart attack treatment and minimize risk.