Summary
Bleeding risk (often perceived, rather than actual) is a common reason for cessation
of oral anticoagulation with Vitamin K antagonists (VKA). We investigate clinical
outcomes in a consecutive population of VKA naïve atrial fibrillation (AF) patients,
who initiated VKA therapy in our clinic. We included consecutive VKA-naíve patients
with non valvular AF, initiated on VKA therapy in our anticoagulation outpatient clinic
in 2009. During follow-up, adverse events [thrombotic/vascular events (stroke, acute
coronary syndrome, acute heart failure and cardiac death), major bleeding and death],
and VKA cessation were recorded. At the end of the follow-up, we determined time within
therapeutic range (TTR), using a linear approximation (Rosendaal method). We studied
529 patients (49% male, median age 76), median follow-up 835 days (IQR 719−954). During
this period 114 patients stopped VKA treatment. 63 patients suffered a thrombotic/cardiovascular
event (5.17%/year, 27 thrombotic/ischaemic strokes), 51 major bleeding (4.19%/year)
and 48 died (3.94%/year). Median TTR was 54% (34a57). On multivariate analysis (adjusted
by CHA2DS2-VASc score), VKA cessation was associated with death [Hazard Ratio (HR) 3.43; p<0.001],
stroke [4.21; p=0.001] and thrombotic/cardiovascular events [2.72; p<0.001]. Independent
risk factors for major bleeding were age [1.08; p<0.001], previous stroke [1.85; p=0.049],
and TTR [0.97; p=0.001], but not VKA cessation. In conclusion, in AF patients AF,
VKA cessation is independently associated with mortality stroke and cardiovascular
events. Specifically, VKA cessation independently increased the risk of stroke, even
after adjusting for CHA2DS2-VASc score. TTR was an independent risk factor for major bleeding following initiation
of VKA therapy.
Note: The editorial process for this paper was fully handled by Prof Christian Weber,
Editor in Chief.
Keywords
Atrial fibrillation - oral anticoagulants - mortality - thrombosis
