Title: Are Atrial Fibrillation Patients Receiving Warfarin in Accordance With Stroke Risk?
Topic: Arrhythmias
Date Posted: 6/2/2010
Author(s): Zimetbaum PJ, Thosani A, Yu HT, et al.
Citation: Am J Med 2010;123:446-453.
Clinical Trial: No
Study Question: To what extent are guidelines for anticoagulation of patients with atrial fibrillation (AF) adhered to in clinical practice?
Methods: This was a retrospective analysis of 171,393 patients with AF entered into a MarketScan claims and encounters database in 2003-2007. The CHADS2 score (1 point each for congestive heart failure, hypertension, age >75 years, and diabetes, and 2 points for prior stroke or thromboembolism) was calculated for each patient. Anticoagulation with warfarin was noted.
Results: Overall, warfarin was prescribed for 42.6% of the study population. There were no significant differences in warfarin utilization between the individual CHADS2 score categories. In high-risk patients with a CHADS2 score of 3-6, 42.1% received a prescription for warfarin.
Conclusions: Warfarin is underutilized in high-risk AF patients in clinical practice in the United States.
Perspective: The 2006 American College of Cardiology/American Heart Association/European Society of Cardiology guidelines for AF management recommend anticoagulation with warfarin for patients with a CHADS2 score >2. The results of this study suggest that this recommendation often is not incorporated into clinical practice. However, the CHADS2 scoring system was not widely recognized until the AF guidelines were published in 2006. Although adherence to guidelines has hopefully improved in the past 4 years, it is likely that there still is underutilization of warfarin. To what extent this underutilization is due to the reluctance of physicians to expose patients to the perceived risk of bleeding complications and/or to the reluctance of patients to take a ‘rat poison’ is unclear. It seems likely that both physician and patient compliance will improve once a direct thrombin inhibitor becomes available in clinical practice. Fred Morady, M.D., F.A.C.C.
Title: A Risk Score to Predict Bleeding in Patients With Acute Coronary Syndromes
Topic: General Cardiology
Date Posted: 5/31/2010 5:00:00 PM
Author(s): Mehran R, Pocock SJ, Nikolsky E, et al.
Citation: J Am Coll Cardiol 2010;55:2556-2566.
Clinical Trial: No
Study Question: What are the risk factors that predict the risk and implications of major bleeding in acute coronary syndromes (ACS)?
Methods: A total of 17,421 patients with ACS (including non–ST-segment elevation myocardial infarction [STEMI], STEMI, and biomarker-negative ACS) were studied in the ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) and the HORIZONS-AMI (Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction) trials. An integer risk score for major bleeding within 30 days was developed from a multivariable logistic regression model.
Results: Non-coronary artery bypass graft surgery (CABG)-related major bleeding within 30 days occurred in 744 patients (7.3%) and had six independent baseline predictors (female sex, advanced age, elevated serum creatinine and white blood cell count, anemia, non–STEMI, or STEMI) and one treatment-related variable (use of heparin + a glycoprotein IIb/IIIa inhibitor rather than bivalirudin alone) (model c-statistic = 0.74). The integer risk score differentiated patients with a 30-day rate of non–CABG-related major bleeding ranging from 1% to over 40%. In a time-updated covariate-adjusted Cox proportional hazards regression model, major bleeding was an independent predictor of a 3.2-fold increase in mortality. The link to mortality risk was strongest for non–CABG-related Thrombolysis In Myocardial Infarction (TIMI)-defined major bleeding followed by non-TIMI major bleeding with or without blood transfusions, whereas isolated large hematomas and CABG-related bleeding were not significantly associated with subsequent mortality.
Conclusions: The authors concluded that a simple risk score based on seven variables identifies patients at increased risk for non–CABG-related bleeding and subsequent 1-year mortality.
Perspective: The present analysis suggests that the risk of experiencing a non–CABG-related major bleed within 30 days of presentation varies greatly, depending to a large extent on baseline clinical characteristics, laboratory results, and choice of anticoagulation regimen. A simple integer-based scoring system incorporating six readily available baseline clinical and laboratory variables plus the antithrombotic regimen demonstrated good performance in identifying patients with different risks for major bleeding. Although the risk score needs to be externally validated in another large data set, this knowledge will aid in the accurate risk stratification of patients with ACS, facilitating individualized and optimal decision-making for the patient at high risk of bleeding and mortality. Debabrata Mukherjee, M.D., F.A.C.C.
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