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Researchers Examine the Unwarranted Use of Treatments for Patients Undergoing Heart Surgery, Experiencing Leg Fractures

Posted on: Monday, 12 December 2005, 12:00 CST

ATLANTA, Dec. 12 /PRNewswire/ -- Red blood cell transfusions are often used to prevent complications after heart surgery, despite the existence of treatment guidelines recommending against this intervention. There is also uncertainty about the need for preventive anticoagulants or blood thinners to prevent blood clots in the leg after lower leg injuries, but many doctors still prescribe them. Concern for patient safety and rising health care costs has caused many physicians to re-examine accepted standards of practice. Two new studies presented today at the 47th Annual Meeting of the American Society of Hematology suggest that these interventions may be unnecessary, and occasionally even detrimental, when applied routinely to all patients.

"Despite the implementation of new guidelines and original thinking, many doctors continue to over-prescribe medication in order to prevent further complications for their patients. However, targeted therapies are becoming the focus of medicine and will enable us to better treat our patients," said Stanley Schrier, M.D., Stanford University School of Medicine, Stanford, Calif. "If we can better recognize patients' specific needs, we can not only help deter unwarranted side effects, but also shield our patients from treatments that may be unnecessary and contributing to rising health care costs."

Morbid Risks of Unnecessary Red Blood Cell Transfusion in Stable Coronary Artery Bypass Graft Patients [Abstract 427]

Coronary artery bypass graft (CABG) surgery is one of the most commonly performed major operations in the U.S., with almost 350,000 conducted each year. CABG is recommended for patients whose arteries have become clogged by a build-up of fat, cholesterol, or other substances. During the procedure, surgeons use blood vessels from other parts of the body to reroute the blood flow around the clogged artery.

Twenty percent of patients undergoing cardiac operations use 80 percent of the blood products attributed to cardiac surgical use, according to the American College of Cardiology and the American Heart Association. In order to determine whether red blood cell (RBC) transfusions were over-utilized in CABG patients, investigators of the Multicenter Study of Perioperative Ischemia Research Group (MCSPI) evaluated the effects of RBC transfusions in stable CABG patients who, according to established guidelines, were not appropriate candidates for transfusion.

Researchers found that in this carefully selected group of stable CABG patients, the use of RBC transfusions was associated with an increased risk for cardiac, renal, and infectious morbidity, as well as increased health care expenses, including hospitalization, without any detectable benefits.

The study included 940 stable CABG patients from the 5,065 patients enrolled in the Multicenter Study of Perioperative Ischemia Epidemiology II (EPI II) Study who had a low to moderate risk profile, low postoperative hemoglobin levels, minimal postoperative blood loss, and no evidence of a morbid event on the day of surgery. Researchers tracked the effect of the RBC transfusion for the first 24 postoperative hours, and kept an eye on organ outcomes and markers of RBC utilization for the first postoperative day through hospital discharge. Of the 940 stable patients studied, 20.2 percent received RBC transfusions. These patients were more likely to suffer myocardial infarction (heart attack), renal dysfunction, renal failure requiring dialysis, and/or harvest site wound infection.

"We found that red blood cell transfusions for CABG patients are often overused and administered to patients who may actually suffer from the results," said Jack Levin, M.D., University of California School of Medicine, San Francisco, Calif. "Although guidelines exist for the appropriate use of transfusions, more education is needed for physicians to ensure that we do not inadvertently hurt our patients by over-treating them, which may also lead to increased health care expenses."

A Prospective Cohort Study of the Epidemiology of Symptomatic Venous Thromboembolism (VTE) After Isolated Leg Fractures Distal to the Knee Without Thromboprophylaxis [Abstract 583]

Lower leg fractures are very common injuries affecting more than 500,000 people in North America each year. Such patients are known to have an increased risk of blood clots in the leg called deep vein thrombosis (DVT), both as a result of the injury and consequent immobilization. These blood clots can occasionally travel to the lung, known as a pulmonary embolism (PE), where they may produce symptoms of respiratory dysfunction. Together, DVT and PE are manifestations of a single disease entity, known as venous thromboembolism (VTE).

In research studies, as many as 40 percent of patients who have sustained lower leg fractures are reported to have DVT, as shown through the use of screening venography, X-rays of veins of the legs after injection of a contrast dye. On the basis of this risk estimate, these patients are often prescribed preventive blood thinner medication, sometimes for several weeks, until the period of immobilization is over and the cast comes off. However, the vast majority of DVTs detected by venography are clinically silent at the time of detection, and their significance is not well understood. Therefore, investigators and clinicians are unsure whether the use of venography is an appropriate outcome measure to assess the burden of DVT in this population or to form the basis for recommending preventive therapy for VTE.

Researchers from the University of Toronto conducted the first large, multicenter, prospective study in patients with isolated fractures below the knee, designed to determine the frequency of blood clots that produce symptoms. The study was conducted from August 2002 until June 2005 at five hospitals in Ontario, where 1,200 patients with fractures of the lower leg were enrolled within 96 hours of injury. They ranged in age from 16 to 93 years (with an average age of 45 years, 60 percent were female) and included patients with fractures of the patella, tibia, fibula, and foot. Most injuries were caused by falls, vehicular accidents, sports injuries, and occupational injuries.

Eighty-two percent of this group had a cast or brace for an average of six weeks after the fracture, and seven percent had their fractures treated surgically. All patients were followed for a three-month period after injury and the use of blood thinners was not allowed. If symptoms of DVT or PE occurred, they were investigated in a standardized manner. Results were taken from 1,174 patients who completed the three-month follow-up period. Only seven of these 1,174 patients developed symptomatic VTE (five had DVT, two had PE). No patient had a fatal pulmonary embolism.

"Based on our results, symptomatic VTE was so uncommon in patients with such fractures that routine use of anticoagulants to prevent blood clots in this patient population is not warranted or cost effective. Additionally, we were unable to identify any high-risk subgroups within this group of patients that might be suitable for targeted prophylaxis," said Rita Selby, M.D., M.Sc., University of Toronto, Toronto, Ontario. "This study also highlights the discrepancy in the incidence of VTE between studies using venography and those utilizing clinical endpoints, and underscores the need to reevaluate the methods used in conducting clinical trials on VTE prevention."

The American Society of Hematology (http://www.hematology.org/) is the world's largest professional society concerned with the causes and treatment of blood disorders. Its mission is to further the understanding, diagnosis, treatment, and prevention of disorders affecting blood, bone marrow, and the immunologic, hemostatic, and vascular systems, by promoting research, clinical care, education, training, and advocacy in hematology.

American Society of Hematology

CONTACT: Leslie Priest of Spectrum Science Communications+1-202-955-6222, lpriest@spectrumscience.com, for American Society ofHematology; Aislinn Raedy of American Society of Hematology,+1-202-776-0544, araedy@hematology.org; or On-site (12-9 to 12-13):+1-404-222-5705

Web site: http://www.hematology.org/

Source: PRNewswire

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