Impact of AF screening on stroke prevention influenced by systolic blood pressure

Screening for atrial fibrillation (AF) via continuous monitoring with an implantable loop recorder (ILR) was more efficacious in terms of stroke prevention for participants with higher systolic blood pressure (BP). In addition, higher systolic BP was related to an increased risk of longer AF episodes, which may partially explain the association between systolic BP and stroke prevention via AF screening.

Hypertension is a known risk factor for both clinical AF and AF-related stroke. However, it remains unclear whether continuous screening for AF can prevent strokes in individuals with high systolic BP. To address this, Dr Lucas Yixi Xing (Copenhagen University Hospital, Denmark) and colleagues conducted a post-hoc analysis of the LOOP study (NCT02036450) [1]. The previously published LOOP study included 6,004 participants ≥70 years old without AF but with ≥1 of the following stroke risk factors: hypertension, diabetes mellitus, heart failure, or previous stroke [2]. The participants were randomised to continuous monitoring with ILR and subsequent anticoagulation therapy if AF was detected (n=4,503) or standard therapy (n=1,501) to assess whether the intervention was able to prevent strokes. Although ILR screening was associated with a 3-fold increase in the detection of AF and subsequent initiation of anticoagulation therapy, no significant risk reduction in stroke or systemic arterial embolism was observed (HR 0.80; P=0.11). The current post-hoc analysis assessed the relation between AF screening and hypertension in stroke prevention [1]. In addition, the research group investigated how systolic BP affected AF occurrence and AF burden.

Participants with a higher systolic BP (≥150 mmHg) benefitted significantly more from ILR screening for AF in terms of stroke prevention than participants with a systolic BP <150 mmHg (HR 0.56 vs HR 1.16; P for interaction=0.0077; see Figure). Although systolic BP did not significantly influence the occurrence of new-onset AF in the intervention arm (HR 1.10; 95% CI 0.92‒1.33), participants with a systolic BP ≥150 mmHg displayed significantly higher rates of AF episodes that lasted ≥24 hours (HR 1.69; 95% CI 1.07‒2.66).

Figure: Interaction between systolic BP and the effect of ILR screening on stroke or systemic arterial embolism [1]



 

 

 

 

 

 

 

 

 

CI, confidence interval; ILR, implantable loop recorder.

“The current analysis showed that the benefit of ILR screening for AF on stroke prevention increased with increasing systolic BP. This effect may be partially explained by the finding that high systolic BP was associated with an increased risk for longer AF episodes. However, these results should be interpreted with caution since this was a post-hoc analysis, and BP measurement was only taken at a single point,” concluded Dr Xing.

1. Xing LY, et al. Systolic blood pressure and effects of screening for atrial fibrillation with long-term continuous monitoring. What is new on stroke prevention, EHRA 2022, 3–5 April, Copenhagen, Denmark.
2. Svendsen JH, et al. Lancet. 2021;398(10310):1507‒1516.

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Posted on 31 May, 202213 June, 2022