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. 2022 Sep 28;3(6Part A):621-628.
doi: 10.1016/j.hroo.2022.09.018. eCollection 2022 Dec.

Residual stroke risk despite oral anticoagulation in patients with atrial fibrillation

Matthew A Carlisle  1 , Peter Shrader  1   2 , Marat Fudim  1   2 , Karen S Pieper  1   2 , Rosalia G Blanco  1   2 , Gregg C Fonarow  3 , Gerald V Naccarelli  4 , Bernard J Gersh  5 , James A Reiffel  6 , Peter R Kowey  7   8 , Benjamin A Steinberg  9 , James V Freeman  10 , Michael D Ezekowitz  7   8 , Daniel E Singer  11 , Larry A Allen  12 , Paul S Chan  13 , Sean D Pokorney  1   2 , Eric D Peterson  1   2 , Jonathan P Piccini  1   2 ; ORBIT AF Patients and Investigators
Affiliations

Residual stroke risk despite oral anticoagulation in patients with atrial fibrillation

Matthew A Carlisle et al. Heart Rhythm O2. .

Abstract

Background: Oral anticoagulation (OAC) reduces the risk of thromboembolic events in patients with atrial fibrillation (AF); however, thromboembolism (TE) still can occur despite OAC. Factors associated with residual risk for stroke, systemic embolism, or transient ischemic attack events despite OAC have not been well described.

Objective: The purpose of this study was to evaluate the residual risk of thromboembolic events in patients with AF despite OAC.

Methods: A total of 18,955 patients were analyzed in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF I and II) using multivariable Cox proportional hazard modeling. Mean age was 72 ± 10.7, and 42% were women. There were 451 outcome events.

Results: The risk of TE despite OAC increased with CHA2DS2-VASc score: 0.76 (95% confidence interval [CI] 0.63-0.92) events per 100 patient-years for CHA2DS2-VASc score <4 vs 2.01 (95% CI 1.81-2.24) events per 100-patient years for CHA2DS2-VASc score >4. Factors associated with increased risk were previous stroke or transient ischemic attack (hazard ratio [HR] 2.87; 95% CI 2.30-3.59; P <.001), female sex (HR 1.52; 95% CI 1.24-1.86; P <.001), hypertension (HR 1.50; 95% CI 1.09-2.06; P = .01), and permanent AF (HR 1.47; 95% CI 1.12-1.94; P = .001). When transient ischemic attack was excluded, the results were similar, but permanent AF was no longer significantly associated with thromboembolic events.

Conclusion: Patients with AF have a residual risk of TE with increasing CHA2DS2-VASc score despite OAC. Key risk markers include previous stroke/transient ischemic attack, female sex, hypertension, and permanent AF.

Keywords: Atrial fibrillation; Oral anticoagulation; Residual risk; Stroke; Thromboembolism.

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Figures

Figure 1
Figure 1
Independent factors associated with thromboembolism despite oral anticoagulation (direct-acting oral anticoagulation or warfarin). AF = atrial fibrillation; CI = confidence interval; COPD = chronic obstructive pulmonary disease; eGFR = estimated glomerular filtration rate; HR = hazard ratio; MI = myocardial infarction; TIA = transient ischemic attack.
Figure 2
Figure 2
Independent factors associated with thromboembolism despite direct-acting oral anticoagulation. Abbreviations as in Figure 1.
Figure 3
Figure 3
Independent factors associated with thromboembolism despite warfarin. PVD = peripheral vascular disease; other abbreviations as in Figure 1.
See this image and copyright information in PMC

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