Есть ли критическое значение длительности пароксизмов фибрилляции предсердий, при котором повышается риск инсульта? Исследование «TRENDS»
Official Title: The TRENDS Study: Is There a Critical Value of Daily Atrial Tachyarrhythmia Burden From Device Diagnostics That Raises Stroke Risk?
Event: ACC Annual Scientific Session 2008
Topic(s): Arrhythmias
Presenter: Taya V. Glotzer
Writer(s): Amit Kumar
Date Posted: 4/1/2008
Summary
Device-detected atrial tachycardia (AT)/atrial fibrillation (AF) burden can be used to stratify the risk of thromboembolic events (TEs). The precise AT/AF burden threshold that warrants additional medical intervention needs to be determined in further studies.
Background
AF, sustained as well as paroxysmal, is associated with increased stroke risk; AF patients are prescribed warfarin in order to prevent such strokes. The risk posed by very short durations of AF, however, remains unknown. Modern implantable devices are capable of accurately detecting and recording AT/AF events in the heart. The TRENDS study was a prospective, observational study that evaluated the relationship between device-detected AT/AF burden and the risk of TEs.
Study Design
116 sites in the TRENDS study enrolled more than 3000 patients, of which 2813 met inclusion criteria. 2486 of these patients had at least 30 days of device data available and were selected for analysis. Inclusion criteria were implantation of a cardiac rhythm device capable of monitoring AT/AF burden and ≥1 stroke risk factor (heart failure, hypertension, age ≥65 years, diabetes, or prior stroke). AT/AF burden was defined as the longest total duration of AT/AF in hours (h) on any given day during a 30-day rolling window before the first TE or the end of follow-up. Device data were retrieved at 3-month intervals; TEs, the primary outcome of the study, were adjudicated by study neurologists. The median value for all 30-day windows with non-zero AT/AF burden was 5.5 h/day, and the windows were divided into zero burden, low burden (<5.5 h on each day/window), and high burden (≥5.5 h on at least 1 day/window).
Results and Conclusions
The mean age of patients was 71 years and the mean CHADS2 risk score was 2.2; 21% of patients were on warfarin and 62% were on aspirin. During an average follow-up of 1.4 years, forty TEs occurred. The TE rate for the zero AT/AF burden group was 1.1% per year compared to 1.7% per year for any AT/AF burden group, and was subdivided into high burden (2.4% per year) and low burden (1.1% per year). Compared to zero burden, the hazard ratios in the low and high burden groups in a multivariate analysis adjusted for stroke risk factors and time-dependent warfarin/aspirin use were 0.98 (95% confidence interval [CI], 0.34-2.82; p = 0.97) for the low burden group and 2.18 (95% CI, 0.95-5.03; p = 0.07) for the high burden group.
The results suggest that device-detected AT/AF burden ≥5.5 h on any day during the preceding 30 days doubles the risk for TE independent of known risk factors and antithrombotic therapy. Further studies are needed to precisely identify the AT/AF burden threshold that merits additional medical intervention. Of note, the observed stroke rate in this study was low compared to prior studies of AF patients with similar risk profiles.
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