The unappreciated importance of blood pressure in recent and older atrial fibrillation trials

Atrial fibrillation and arterial hypertension represent two common clinical conditions that frequently coexist, especially in older individuals, and are associated with increased risk of stroke. Antihypertensive therapy reduces the risk of stroke by approximately 40%. It has been observed that stroke rates were reduced by 10% for every 2-mmHg reduction of blood pressure. Antithrombotic therapy reduces significantly the risk for ischemic stroke in patients with atrial fibrillation at the expense of increased risk of intracranial bleeding. The importance of hypertension in patients with atrial fibrillation is recognized by its inclusion both in the CHA2DS2-VASc (risk for stroke) and the HAS-BLED (Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly, Drugs/alcohol concomitantly) scores (risk for bleeding) and the presence of hypertension alone is an indication to initiate antithrombotic treatment. However, blood pressure remains remarkably unappreciated in previous and recent atrial fibrillation trials. Very limited, if any, data are provided regarding blood pressure, including in-study and final blood pressure levels, blood pressure control, and concomitant antihypertensive medication. In contrast, several lines of evidence point toward a significant role of pre and in-treatment blood pressure for ischemic and hemorrhagic stroke in patients with atrial fibrillation as well as for the incidence of intracranial bleeding during antithrombotic treatment. We propose that regular blood pressure recording should be mandatory in all future studies with antithrombotic therapy, analyses based on final and in-study blood pressure values, hypertension control, and antihypertensive medication should be performed, and the outcome be adjusted for blood pressure-related variables.