br Conflict of interest br Introduction

Conflict of interest
Introduction Congestive MM-102 cost failure (CHF) is known as an established risk factor for stroke in patients with atrial fibrillation (AF) [1]. However, diagnosing CHF is occasionally difficult because of the symptoms that are similar to those of AF, such as dyspnea and palpitations. The adjusted annual stroke rates in AF patients with a CHADS2 (CHF, hypertension, age≥75 years, diabetes, stroke [doubled]) scores of 0 and 1 were reported to be 1.9% and 2.8%, respectively, but these patients were not necessarily considered to have a low-risk for stroke [2]. It can be speculated that latent CHF might have been undiagnosed in patients with low CHADS2 scores. B-type natriuretic peptide (BNP) can be used as a marker for the differential diagnosis of CHF and could serve as a risk marker in addition to clinical assessment. D-dimer can be used as a coagulation marker in patients with AF [3–5]. We reported that the D-dimer levels predicted subsequent thromboembolic events in AF patients and that BNP levels could be a useful marker for predicting thromboembolic events [6,7]. Recently, the European Society of Cardiology guideline [8] recommended that CHA2DS2–VASc (CHF/left ventricular dysfunction, hypertension, age≥75 years [doubled], diabetes, stroke [doubled], vascular disease, age of 65–74 years, and sex category [female]) score [9] instead of CHADS2 score should be used for risk stratification. In the present study, we analyzed D-dimer levels in relation to CHADS2 and CHA2DS2–VASc scores to evaluate the usefulness of measuring BNP levels in AF patients before initiating anticoagulant therapy.
Methods In our present study, we performed a post hoc analysis of the results of our previous study [10]. Briefly, 59 patients for whom BNP and D-dimer levels were determined on the same day and who had not started warfarin therapy were included. Data were presented as mean±SD, median (interquartile range), or percentage values, as appropriate. Comparisons between the 2 groups of data were made with the unpaired Student t test or Mann–Whitney test, as appropriate. Event frequencies were compared using the chi-square test. A p<0.05 was considered statistically significant. The statistical software package JMP (version 9, SAS Institute, Cary, NC, USA) was used for the analyses. The cutoff values for D-dimer and BNP levels were set at 0.5μg/mL and 100pg/mL, respectively, according to previous reports [6,10].
Results The clinical characteristics of the patients are presented in Table 1. The mean CHADS2 score was 2.0±1.1. There were 6, 13, and 40 patients with CHADS2 scores of 0, 1, and ≥2, respectively. The D-dimer levels were significantly higher in the patients with CHADS2 scores ≥2 than in Expression vector with CHADS2 scores of 0–1 (median D-dimer level, 1.16μg/mL [0.72–3.23μg/mL] vs. 0.36μg/mL [0.0–0.44μg/mL], p<0.01). In the patients with clinically diagnosed CHF (NYHA class ≥II symptoms and/or congestive signs requiring loop diuretics), the median BNP level was 371pg/mL (236–450pg/mL), and BNP levels were elevated (≥100pg/mL) in 24 (96%) of the 25 patients. In the 34 patients without CHF, the median BNP level was 77pg/mL (26–175pg/mL), and BNP levels were elevated in 16 patients (47%). Fig. 1 shows the percentage of patients with high D-dimer levels (≥0.5μg/mL) in relation to the CHADS2 scores and BNP levels. The D-dimer levels were elevated in 33 (83%) of the 40 patients with CHADS2 scores ≥2. None of the patients with CHADS2 scores of 1 had CHF. Among the 19 patients with CHADS2 scores of 0 or 1, the D-dimer levels were elevated in 3 (43%) of the 7 patients with elevated BNP levels and in only 1 (8.3%) of the 12 patients whose BNP levels were not elevated (p=0.075). Furthermore, in 6 patients with CHADS2 scores of 0, the D-dimer levels were elevated in 1 of the 2 patients with elevated BNP levels but not in the remaining 4 patients whose BNP levels were not elevated.