Individual Risk Factors Should Be Considered
In this methodologically-correct study (1), the results are misinterpreted, and the individual risk factors of increasing treatment safety are not taken into account:
In 38% of the vitamin K antagonist (VKA) group, the INR international normalized ratio) value was above 3. In 13% of the VKA group, the INR was above 2.5. This means that for around 50% of these patients the dose is set too high, as shown by Hylek in 1994 (2) and again by Takarada in 2014 (3). Protection against thrombosis in the group with an INR above 2.0 is not higher than in the group with an INR between 1.6 and 2.0. In contrast, the risk of bleeding is more than twice as high with an INR above 2.5 (3).
It can therefore be assumed that major bleeding, and especially cerebral hemorrhage, occurs less frequently with the correct application of the VKA than with direct oral anticoagulants (DOACs).
Unfortunately, the article did not discuss whether the frequency of major bleeding increased following a combination of platelet aggregation inhibitors or non-steroidal anti-inflammatory drugs with anticoagulants.
Further, it did not state whether there were differences between apixaban and rivaroxaban with respect to the frequency and severity of major bleeding, and especially cerebral and gastrointestinal bleeding.
The question also arises: why was tranexamic acid not injected in cases of major cerebral hemorrhage (4)?
Prof. Dr. med. Dr. Ing. Holger Kiesewetter
Berlin, Germany, firstname.lastname@example.org
Conflict of interest statement
The author declares that no conflict of interest exists.
|1.||Lindhoff-Last E, Herrmann E, Lindau S, et al.: Severe hemorrhage associated with oral anticoagulants—a prospective observational study of the clinical course during treatment with vitamin K antagonists or direct oral anticoagulants. Dtsch Arztebl Int 2020; 117: 312–9 VOLLTEXT|
|2.||Hylek EM, Singer DE: Risk factors for intacranial hemorrhage in outpatients taking warfarin. Ann Intern Med 1994; 120: 897–902 CrossRef MEDLINE|
|3.||Takarada K, Sato M, Goto M, et al: Long-term PT-INR levels and the clinical events in the patients with non-valvular atrial fibrillation: a special reference to low-intensity warfarin therapy J Cardiol 2014; 64: 127–32 CrossRef MEDLINE|
|4.||Chan DYC, Tsang ACO, Li LF, et al: Improving survival with tranexamic acid in cerebral contusions or traumatic subarachnoid hemorrhage: univariate and multivariate analysis of independent factors associated with lower mortality. World Neurosurg 2019; 125: e665–e70 CrossRef MEDLINE|