Association Between Inappropriately Dosed Anticoagulation Therapy With Stroke Severity and Outcomes in Patients With Atrial Fibrillation

The use of reduced DOAC doses in atrial fibrillation patients does not always lead to good anticoagulation levels and avoid adverse events

BACKGROUND

The MAS study (Blood Advances 2024) showed that a high proportion of Italian AF patients treated with direct oral anticoagulants (DOACs) receive reduced doses. This sub-analysis of MAS data aimed to analyze the effects of reduced (appropriate or not)- or standard-dose use on DOAC activity assessed at baseline and the occurrence of thrombotic or bleeding complications during follow-up.

METHODS

The MAS study design, the methods for DOAC measurement, the results, and the adverse events during follow-up, are described in detail elsewhere.

RESULTS

Seven hundred AF patients (42 % of the total 1657) received a reduced dose (considered inappropriate in 140 [20 %]). They were older, more frequently women, with lower body mass index (BMI), hemoglobin levels, and creatinine clearance. They more often had cerebral or cardiovascular diseases, were taking more medications, with higher scores for thrombotic or bleeding risk. Despite the use of low doses, 133 (19.0 %) patients had high standardized C-trough DOAC levels and experienced a high proportion of bleeding events (8.3 % per year). Conversely, some patients (4.7 %) had very low levels, resulting in a high incidence of thrombotic events (6.7 % per year). No difference was detected if the reduced dose was appropriate or not.

CONCLUSION

The unpredictable, highly variable inter-individual anticoagulant effect of DOACs may lead to either too low or too high anticoagulant levels, increasing the risk of thrombotic or bleeding events. This is particularly relevant for patients with high-risk conditions, such as those chosen for reduced-dose treatment. Further studies are needed to investigate this important clinical issue.

Meta-analysis of outcomes following intravenous thrombolysis in patients with ischemic stroke on direct oral anticoagulants

BACKGROUND

There has been debate on the use of intravenous thrombolysis (IVT) in patients with ischemic stroke and the recent use of direct oral anticoagulants (DOACs). Studies have compared these patients with non-DOAC groups in terms of outcomes. Herein, we aimed to systematically investigate the association between DOAC use and IVT's efficacy and safety outcomes.

RESULTS

A comprehensive systematic search was performed in PubMed, Embase, Scopus, and the Web of Science for the identification of relevant studies. After screening and data extraction, a random-effect meta-analysis was performed to calculate the odds ratio (OR) and 95% confidence interval (CI) for comparison of outcomes between patients on DOAC and controls. Six studies were included in the final review. They investigated a total of 254,742 patients, among which 3,499 had recent use of DOACs. The most commonly used DOACs were rivaroxaban and apixaban. The patients on DOAC had significantly higher rates of atrial fibrillation, hypertension, diabetes, and smoking. Good functional outcome defined by modified Rankin Scale (mRS) 0-2 was significantly lower in patients who received DOACs (OR 0.71, 95% CI 0.62 to 0.81, P < 0.01). However, in the subgroup analysis of 90-day mRS 0-2, there was no significant difference between groups (OR 0.71, 95% 0.46 to 1.11, P = 0.14). All-cause mortality was not different between the groups (OR 1.02, 95% CI 0.68 to 1.52, P = 0.93). Similarly, there was no significant difference in either of the in-hospital and 90-day mortality subgroups. Regarding symptomatic intracranial hemorrhage (sICH), the previous DOAC use was not associated with an increased risk of bleeding (OR 0.98, 95% CI 0.69 to 1.39, P = 0.92). A similar finding was observed for the meta-analysis of any ICH (OR 1.15, 95% CI 0.94 to 1.40, P = 0.18).

CONCLUSIONS

Based on our findings, IVT could be considered as a treatment option in ischemic stroke patients with recent use of DOACs since it was not associated with an increased risk of sICH, as suggested by earlier studies. Further larger studies are needed to confirm these findings and establish the safety of IVT in patients on DOAC.