Atrial Fibrillation, Anticoagulation Treatment and Hypertension

1.0 Introduction

Atrial fibrillation (AF) is the most common cardiac arrhythmia in hypertensive patients while arterial hypertension (HTN) represents the most common comorbidity in patients with AF. In recent clinical trials that assessed the effect of direct oral anticoagulants in patients with AF, 80–90% of included patients suffered from HTN (1). These two conditions frequently coexist because they share common risk factors (diabetes mellitus, obesity, metabolic syndrome, smoking, alcohol consumption) but also because HTN per se increases the hazard for the development of AF (2). The presence of HTN increases the risk of AF by up to 73% (especially in the presence of left ventricular hypertrophy) (3) while arterial blood pressure (BP) levels of 120-130/60-69 mmHg confer the lowest risk for AF (4). In addition, there is a linear correlation between BP levels and the risk of ischemic or hemorrhagic stroke (5) while in patients with AF, the presence of HTN multiplies the annual risk of stroke by up to three-fold (6).

In AF patients receiving anticoagulation optimal BP control is a major determinant for the prevention of haemorrhagic complications. On the other hand, AF increases the risk of stroke by up to five and seventeenfold in non-valvular and valvular heart disease respectively. Without preventive treatment, each year approximately 1 in 20 patients (5%) with AF will have a stroke (2,7,8). Thus, the use of oral anticoagulants (OAC) is imperative since 2/3 of strokes due to AF are preventable with appropriate anticoagulant therapy (9). Taking into consideration all the above, optimal blood pressure control might decrease not only the AF burden in hypertensive patients but also prevent hemorrhagic and bleeding complications of OAC therapy in AF patients.

 

2.0 Oral Anticoagulation In Hypertensive Patients With Atrial Fibrillation

The introduction of the CHA2DS2-VASc (Congestive Heart failure, hypertension, Age ≥75 (doubled), Diabetes, Stroke (doubled), Vascular disease, Age 65–74, and Sex (female)) score has simplified the initial decision for OAC use in AF patients.

According current ESC guidelines for the management of AF, OAC therapy to prevent thromboembolism is recommended for all male AF patients with a CHA2DS2-VASc score of 2 or more (class of recommendation I level of evidence A) while in male patients with a CHA2DS2-VASc score of 1, OAC therapy should be considered (class of recommendation IIa level of evidence B) (10). In current guidelines there is a sex distinction since female gender increases the thromboembolic risk according the CHA2DS2-VASc score however if the patient has only the sex as risk factor (female gender) then there is no need for OAC therapy. Finally, when OAC is initiated in a patient with AF who is eligible, a direct oral anticoagulant (DOAC) (apixaban, dabigatran, edoxaban, or rivaroxaban), is recommended in preference to a vitamin K antagonist (10). In these guidelines, the presence of hypertension plays a crucial role not only in the determination of thromboembolic risk but also in the determination of hemorrhagic risk. Arterial hypertension (especially when systolic BP levels are > 160 mmHg) represents a significant risk factor for bleeding in anticoagulated patients based on HAS- BLED (Hypertension, Abnormal renal and liver function, Stroke, Bleeding, Labile INR, Elderly, Drugs or alcohol) score. In the Bleeding with Antithrombotic Therapy (BAT) Study (11), a multicentre prospective observational cohort study, 4009 patients receiving oral antithrombotic agents for cardiovascular or cerebrovascular diseases were followed. The purpose of the study was to clarify the association between major bleeding events and BP levels preceding bleeding events in antithrombotic users. In this study, changes in systolic and diastolic BP between entry and the last clinic visit before intracranial hemorrhage (ICH) or extracranial hemorrhage were recorded. In this study, SBP levels during the follow-up period were a strong predictor with a 45% and a 47% increase in risk for 10mmHg higher blood pressure in the first and second 6-month follow up respectively.

The optimal cut-off BP level to predict impending risk of ICH was ≥130/81 mm Hg. Likewise, in the randomized Perindopril Protection Against Recurrent Stroke Study (PROGRESS) trial that enrolled patients with previous stroke or transient ischemic attack, 72% of the patients were under antiplatelet therapy and 10% under OAC (12). In this study, a reduction of 9 mmHg in SBP reduced the relative risk for hemorrhagic stroke by up to 50% while a 12 mmHg decrease in SBP by up to 76% (12). The intensity of anticoagulation involves a balance between prevention of thromboembolism and haemorrhage. The HAS-BLED score should be used in order to assess the bleeding risk in AF patients and to consider correctable risk factors for bleeding just like uncontrolled BP. A high HAS-BLED score by itself though, is not a reason to withhold OAC. The score should be rather used to identify those ‘high risk’ patients (score >_3) for more careful review and follow-up, and as an opportunity to address reversible bleeding risk factors.

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Manolis S. Kallistratos, Leonidas E. Poulimenos, Athanasios J. Manolis Asklepeion General Hospital, Cardiology department

Article by, European Society of Hypertension.