Clinical Benefit of American College of Chest Physicians versus European Society of Cardiology Guidelines for Stroke Prophylaxis in Atrial Fibrillation

BACKGROUND

Guidelines for anticoagulant therapy in patients with atrial fibrillation (AF) conflict with each other. The American College of Chest Physicians (ACCP) guidelines suggest no anticoagulant therapy for patients with a CHADS₂ score of 0. The European Society of Cardiology (ESC) prefer anticoagulant therapy for patients with a CHA₂DS₂-VASc of 1, which includes 65–74-year-olds with a CHADS₂ score of 0. Resolving this conflicting advice is important, because these guidelines have potential to change anticoagulant therapy in 10 % of the AF population.

METHODS

Using the National Registry of Atrial Fibrillation (NRAF) II data set, we compared these guidelines using stroke equivalents. Based on structured review of 23,657 patient records, we identified 65–74-year-old patients with a CHADS₂ stroke score of 0 and no contraindication to warfarin. We used Medicare claims data to ascertain rates of ischemic stroke, intracranial hemorrhage, and other hemorrhage. We calculated net stroke equivalents for these (N = 478) patients using a weight of 1.5 for intracranial hemorrhages (ICH) and 1.0 for ischemic stroke. In a multivariate analysis, we used 14,466 records with documented atrial fibrillation and adjusted for CHADS₂ and HEMORR₂ HAGES score.

RESULTS

In 65–74-year-old patients with a CHADS₂ stroke score of 0, the stroke equivalents per 100 patient-years was 2.6 with warfarin and 2.9 without warfarin; the difference between these two strategies was not significant (0.3 stroke equivalents, 95 % CI −3.2 to 3.7). However, rates of hemorrhage per 100 patient-years were nearly tripled (hazard ratio 2.9; 95 % CI 1.5–5.4; p = 0.0011) with warfarin (21.1) versus without it (7.4). The most common site for major hemorrhage was gastrointestinal (ICD-9 code 578.9).

CONCLUSIONS

By expanding warfarin use to 65-–74-year-olds with a CHADS₂ score of 0, rates of hemorrhages would rise without a significant reduction in stroke equivalents.

Electronic supplementary material

The online version of this article (doi:10.1007/s11606-015-3201-1) contains supplementary material, which is available to authorized users.KEY WORDS: atrial fibrillation, epidemiology, outcomes, stroke, thromboembolismAtrial fibrillation (AF) is the most common cardiac arrhythmia, and stroke prevention is a cornerstone of treatment in these patients. However, guidelines regarding anticoagulant therapy conflict with one another. The 2012 American College of Chest Physicians (ACCP) guidelines recommend the use of oral anticoagulant therapy in patients with AF who have a Congestive heart failure, Hypertension, Age > 75, Diabetes mellitus, and prior Stroke (CHADS₂) score of 1 or greater.¹ ACCP suggests no anticoagulant therapy for patients with a CHADS₂ score of 0.¹ However, the ACCP guidelines remark that there are other factors, such as age 65 to 74 years, female gender, vascular disease, and patient preferences, that may influence the choice of therapy for some patients.These guidelines differ from the 2010 European Society of Cardiology (ESC) (Table 2 The 2012 ESC AF Focused Update³ and the 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society (AHA/ACC/HRS)⁴ recommend anticoagulant therapy if AF patients age 65–74 are female or have vascular disease (because their CHA₂DS₂-VASc score would be 2 or more). However, for other 65–74-year-old patients with a CHADS₂ score of 0 they state that either no antithrombotic therapy or treatment with an oral anticoagulant should (2012 ESC) or may (AHA/ACC/HRS) be considered because their CHA₂DS₂-VASc score would be 1.

Table 1

Atrial Fibrillation Guidelines for Use of Anticoagulant Therapy in 65–74-year-Olds

Clinical trials update from the European Society of Cardiology Heart Failure meeting and the American College of Cardiology: darbepoetin alfa study, ECHOS, and ASCOT-BPLA

This article provides information and a commentary on landmark trials presented at the European Society of Cardiology Heart Failure meeting held in June 2005, relevant to the pathophysiology, prevention and treatment of heart failure. All reports should be considered as preliminary data, as analyses may change in the final publication. The erythropoiesis stimulating protein, darbepoetin alfa, increased haemoglobin levels, improved quality of life and showed a trend for improved exercise duration in anaemic patients with symptomatic chronic heart failure. In the ECHOS study, the selective dopamine agonist nolomirole (CHF1035) showed no benefit in heart failure patients. Preliminary results of the ASCOT-BPLA study, which were reported at the American College of Cardiology meeting in March 2005, showed that in hypertensive patients, treatment with a calcium antagonist plus an ACE inhibitor was more effective at reducing cardiovascular outcomes than atenolol plus a diuretic.