AVK overdose in Covid-19 infected patients

During the Covid-19 pandemic, four patients were admitted to a healthcare centre. They were treated with vitamin K antagonists (AVK). We observed a substantial increase in their International Normalised Ratio (INR). The mean age of these patients was 90 (± 8 years). All had different usual long-term therapy treatments but had fixed doses of AVK to reach a stable INR. No changes to the background regimen were implemented. One patient presented a cough whereas the three others were asymptomatic. In the context of the pandemic, a reverse transcriptase polymerase chain reaction (RT-PCR) for SARS-CoV-2 was carried out for each patient. The results of the RT-PCR rests were all positive and were associated with a substantially increased INR. Mr H. was admitted with an INR of 2.25 which increased to 5.93 the day after RT-PCR positivity. AVK treatment was stopped but the INR one day after was 7.89. Ms J. presented INR values between 1.96 and 4.58, 10 days later. a PCR test was conducted and AVK treatment was stopped, but the INR still increased to 5.85. The INR of Mr R. increased from 1.82 to 8.05, 24 hours after a positive PCR result. Ms F. presented a gradual increase in INR from 1.5 to 3.36, 72 hours after a positive PCR result and three days after discontinuation of AVK. This study suggest a link between the Covid-19 infection and an increased INR. It has been established that SARS-CoV-2 infection induces hypercoagulability in severe forms. Inversely, these four cases show a haemorrhagic risk as the INR increases. There could be a risk of overdose when patients are treated with AVK and are positive for Covid-19. This raises the question of discontinuing AVK and substituting it with another anticoagulant, or performing INR checks more frequently in the context of Covid-19. Moreover, an unexpected increase in INR should indicate the need to conduct a Covid-19 RT-PCR test in the context of this pandemic context.

Time in therapeutic range is lower in women than in men and is not explained by differences in age or comorbidity

BACKGROUND

Time in therapeutic range (TTR) measures the stability of the international normalized ratio in patients on vitamin K antagonists (VKA). Low values are associated with poor outcomes. Women were shown to have lower TTR than men, but the causes are poorly defined. It was suggested that women on VKA are older and more morbid than men, and this could affect the stability of anticoagulation. We aimed to identify variables that affect TTR differently in women and men.

MATERIALS AND METHODS

This is a retrospective study in patients referred to a University hospital anticoagulant clinic. Age, sex, comorbidities, number of daily medications, indication and type of anticoagulant, weekly dosage and distribution, were derived from electronic records. Differences by sex and regression analysis to identify significant modulators of TTR were computed.

RESULTS

1182 women and 1281 men on VKA were studied. Women were older than men (81.5 yrs. ± 11.2 vs 78.4 yrs. ± 12.2), and had lower TTR (65% ± 20.3 vs 69% ± 19.8). Comorbidity was similar between sexes and negatively affected TTR in both. Mechanical valves as an indication to anticoagulation and acenocoumarol as an anticoagulant as opposed to warfarin had a strong negative influence on TTR, while age increased TTR. Being a man rather than a woman afforded more than three TTR points. Number of medications and average anticoagulant dose were equal between sexes.

DISCUSSION

Women have a lower TTR than men, on average below the safety threshold. They were indeed older, but age positively influenced TTR. Since women and men were equally comorbid, neither age nor disease explains differences in TTR. None of the other variables included in the study could explain the gender gap in TTR. Since women are at increased risk of cardioembolic stroke in atrial fibrillation, an effort at defining other causes for the observed differences, closer monitoring and switching to direct anticoagulants whenever possible is warranted.

[Evaluation of the risk of postoperative bleeding complications in hand surgery without interruption of anticoagulant Vitamin K Antagonist (VKA), a retrospective study]

OBJECTIVE

The management of patients on Vitamine K Antagonist (VKA) anticoagulation is a public health issue with surgery being the primary cause of VKA interruption. The aim of this study was to evaluate the bleeding risk in patients operated on hand surgery without interruption of VKA treatment.

PATIENTS AND METHODS

This retrospective, monocentric study was conducted between 2013 and 2015. The inclusion criteria were, as follows: patients on VKA over 18 years of age who had emergency or scheduled surgery without interruption of VKA treatment; INR inferior to 3 analyzed less than 24h before surgery. Exclusion criteria were, as follows: INR superior to 3; interruption of VKA treatment with or without switch to heparin treatment. The primary evaluation parameter was any form of bleeding that occurred during the first 7 post-operative days. The secondary criteria were other surgical complications.

RESULTS

There were 93 patients and 104 procedures. The mean age was 74.36 years (from 27 to 90) with a sex ratio male-to-female of 2.47. The scheduled surgeries were 61.5% against 36.5% for the emergency cases. The mean INR was 2.29 (from 1.07 to 3). One patient presented a postoperative hematoma on the 4th postoperative day, which did not require any revision surgery. There were no other complications reported.

CONCLUSION

The results of this series suggest a small bleeding risk in hand surgery without interruption of VKA treatment provided that IRN is inferior to 3 less than 24hours before the procedure.

[Direct oral anticoagulant associated bleeding]

Direct oral anticoagulants (DOAC) are recommended for stroke prevention in atrial fibrillation and for the treatment of venous thromboembolism. However, they are associated with hemorrhagic complications. Management of DOAC-induced bleeding remains challenging. Activated or non-activated prothrombin concentrates are proposed, although their efficacy to reverse DOAC is uncertain. Therapeutic options also include antidotes: idarucizumab, antidote for dabigatran, has been approved for use whereas andexanet alpha, antidote for anti-Xa agents, and aripazine, antidote for all DOAC, are under development. Other options include hemodialysis for the treatment of dabigatran-associated bleeding and administration of oral charcoal if recent DOAC ingestion. DOAC plasma concentration measurement is necessary to guide DOAC reversal. We propose an update on DOAC-associated bleeding, integrating the availability of dabigatran antidote and the critical place of DOAC concentration measurements.

[Evaluation of the knowledge of patients about the management of treatment with anti-vitamin K drugs in the Service of Cardiology of Ouagadougou]

INTRODUCTION

Vitamin K antagonists (VKA), the most widely prescribed oral anticoagulant therapy, represent a major public health problem by the adverse events related to their use. The aim of this study was to clarify the level of knowledge that patients have about the management of their oral anticoagulant treatment.

PATIENTS AND METHODS

This was a descriptive cross-sectional study performed at Yalgado Ouedraogo university Hospital, over a period of three months starting from March 1st to May 31st 2012. A questionnaire was given to patients receiving VKA treatment for at least a month.

RESULTS

Seventy patients were enrolled in the study of which 30 men. The median age was 49±16 years. Heart disease and venous thromboembolic disease justifying the introduction of VKA treatment were found respectively in 58.6 and 41.4% of the cases. The name of the VKA and the exact reason for the treatment were known respectively in 91.4 and 61.7% of the case. More than half of patients (68.6%) knew that the VKA makes blood more fluid. Forty-six patients (65.7%) cited INR as biological monitoring of treatment but only 28 patients (40%) were aware of INR target values. The majority of patients did not know the risks in case of overdose (72.8%) and underdosing (71.4%). Self-medication by non-steroidal anti-inflammatory drugs was reported by 18 patients (25.7%). Cabbage (74.3%) and lettuce (62.9%) were the main foods reported to be consumed moderately.

CONCLUSION

The knowledge of patients on the management of VKA is fragmentary and remains insufficient to ensure the effectiveness of the treatment. The creation of a therapeutic education program is then necessary.