Effect of diseases on response to vitamin K antagonists

Does Ramadan fasting disrupt international normalised ratio control in warfarin-treated medically stable patients?

AIM

Warfarin is commonly used in patients with thrombotic diseases. This study aimed to evaluate the impact of Ramadan fasting on warfarin efficacy by investigating international normalised ratio (INR) stability in medically stable patients.

METHODS

A retrospective observational study was conducted at King Khalid University Hospital during Ramadan 2016 on fasting adult patients aged above 18 years and receiving warfarin. The INR values during pre-Ramadan, Ramadan and post-Ramadan periods were collected after satisfying the inclusion criteria. Time within the therapeutic range (TTR) during the whole period was estimated using the conventional method.

RESULTS

In total, 101 patients were included in the study. The mean age (SD) was 55.8 ± 15.5 years, and 52.4% were females. The target INR range for 62.4% was 2-3, while 37.6% had a target INR range of 2.5-3.5. An upward trend in the proportion of patients with therapeutic INR was noticed during Ramadan (59.4%) as compared to pre- (56.4%) and post-Ramadan periods (53.5%) respectively. Additionally, the proportions of patients with supratherapeutic and sub-therapeutic INR were the highest and lowest, 23% and 24% respectively post-Ramadan as compared to other periods. Based on target INR categorisation, achieving therapeutic INR during Ramadan was more feasible with the low INR (2-3) compared to the high INR (2.5-3.5) target patients, 63.5% vs 52.6% respectively. TTR estimation revealed 62.4% and 37.6% of the patients had good and poor, respectively, anticoagulation status throughout the study period.

CONCLUSION

Despite the changes in mean INR and proportion of patients with therapeutic INR during Ramadan compared to other non-fasting months, our results confirmed that short-term fasting during Ramadan has no significant influence on INR stability and, consequently, therapeutic efficacy in warfarin-treated medically stable patients.

Hyperthyroidism in severe mitral regurgitation post mechanical mitral valve replacement: the effect on warfarin anticoagulation

A 24-year-old male patient came to the emergency room with melena, gum bleeding and nosebleeds. This patient has a history of mechanical prosthetic mitral valve replacement for severe mitral regurgitation (MR) and consumed warfarin irregularly, but did not come back for regular check-up. Investigations showed greatly increased thyroid function and international normalised ratio (INR) was 15.8. Patients were diagnosed with thyroid storm and bleeding due to prolongation of INR. His hyperthyroid state might have caused increased rate of degradation of vitamin K-dependent clotting factor thereby increased sensitivity to warfarin. Concomitant acute decompensated heart failure, thrombocytopenia and hypoalbuminemia also contributed to his risk of bleeding. Treatment included anti-thyroid therapy as well as warfarin reversal therapy by stopping warfarin, low-dose intravenous vitamin K due to his mechanical prosthetic valve and fresh frozen plasma. In conclusion, hyperthyroidism could increase the response to warfarin so close monitoring is needed to balance the risk of bleeding and thromboembolism.

The impact of acute diarrhea on the coagulation status of patients with vitamin K antagonists

Acute diarrhea is associated with a reduced absorption of both vitamin K antagonists (VKA) and vitamin K itself. To date, the net effect on the coagulation status of subjects with VKA remains elusive. We performed a systematic retrospective single-center analysis using an electronic data extraction approach to identify subjects with plasmatic anticoagulation (either VKA or direct oral anticoagulant (DOAC)) and diarrhea in a German University Hospital over a period of eight years. Acute diarrhea and complete documentation of coagulation status on admission were defined as inclusion criteria, anticoagulation other than VKA/DOAC and obvious inadherence as exclusion criteria. Subjects with VKA/DOAC admitted for hypertension served as control group. Data extraction yielded 356 subjects with gastrointestinal diagnoses and 198 hypertensive subjects, 55 and 83 of whom fulfilled all in- and exclusion criteria. INR values of subjects with VKA were significantly higher in subjects with diarrhea than in hypertensive controls (4.3 ± 3.7 vs. 2.3 ± 0.7, p < 0.001). The distribution of subjects having INR values lower, higher or within the target range differed significantly among groups with a substantially higher prevalence of overanticoagulation in the diarrhea group (46.4% vs. 14.3%, p < 0.001). In a multinomial logistic regression model, acute diarrhea was significantly associated with overanticoagulation (odds ratio 7.2, 95% confidence interval 2.163–23.921; p < 0.001), whereas age, sex, creatinine, and indication of anticoagulation were not (p > 0.05 each). Acute diarrhea is associated with a highly increased risk for overanticoagulation in patients with VKA. Thus, gastroenteritis necessitates a close monitoring of INR in order to identify subjects needing a temporary pause of VKA therapy.

[Autoimmune-related bleeding occurring during combined immunotherapy for lung cancer - Case report]

INTRODUCTION

Specific immune-related adverse events in lung cancer treatment are rare and it is important that they are identified as they may have important adverse consequences. We report such a case here.

CASE REPORT

A Caucasian female diagnosed with KRAS mutant advanced adenocarcinoma of the lung was enrolled in a phase Ib trial assessing the combination of an anti cytotoxic T-lymphocyte- associated protein 4 antibody and a programmed death-Ligand 1 inhibitor. For several years, she had also been taking warfarin for recurrent pulmonary embolism. At day 15 of treatment, she presented with grade 1 haematomas and signs of grade 2 hyperthyroidism. Blood tests revealed a normal number of platelets but an INR increased to 6.5. Thyroid function tests and auto antibodies confirmed the presence of an autoimmune thyroitidis. The study treatment was then stopped and the patient received 1mg/kg of prednisone and 40mg of propranolol. At day 28, the thyroid function and symptoms were normalized. No direct interactions exist between immunotherapy and vitamin K antagonists (VKA) but hyperthyroidism, through pharmacokinetic and metabolic mechanisms, can boost VKA plasma levels and increase INR, leading to hemorrhagic complications.

CONCLUSIONS

This case emphasizes that special consideration should be given to patients with VKA treatment planned to receive immunotherapy.

The optimal anticoagulant therapy for mechanical heart valves in a gallbladder cancer patient with hepatic metastases: A case report

RATIONALE

Developing an optimal anticoagulant strategy poses a challenging task in patients with mechanical heart valves (MHVs) throughout their lifetime. We report an optimal anticoagulant therapy in a cancer patient with hepatic metastases after MHV replacement.

PATIENT CONCERNS

A 68-year-old female with MHVs suffered from gallbladder cancer with hepatic metastases. Her international normalized ratio (INR) fluctuated owing to the declined hepatic function.

DIAGNOSES

Gallbladder cancer and hepatic metastases, with a history of mechanic aortic valve replacement and mitral valve replacement.

INTERVENTIONS

Warfarin was discontinued and Vitamin K1 was immediately administrated via intravenous infusion. low-molecular-weight heparin (LMWH) was regarded as a preferable option, and nadroparin at the dosage of 4100IU daily was administered.

OUTCOMES

No adverse event occurred during the patient's hospitalization and two-week follow up after discharge.

LESSONS

LMWH may represent a reasonable alternative regarding the inhibition of thrombus and bleeding in MHVs carriers with cancer and hepatic metastases.

Enzalutamide-warfarin interaction necessitating warfarin dosage adjustment: A case report of successful clinical management

WHAT IS KNOWN AND OBJECTIVES

Enzalutamide package labeling recommends avoiding concurrent warfarin use due to potential reductions in warfarin concentrations via enzalutamide-associated hepatic enzyme induction. A case of successful management of this interaction via warfarin adjustments is reported.

CASE DESCRIPTION

A 77-year-old Caucasian male, previously relatively stable on warfarin 42-45 mg weekly, reported to clinic after the recent start of enzalutamide and subsequent hospitalization with a subtherapeutic International Normalized Ratio (INR). A 50% increase in weekly warfarin dose resulted in a therapeutic INR. Enzalutamide was temporarily discontinued, and a 33% weekly warfarin dose decrease resulted in two therapeutic INRs.

WHAT IS NEW AND CONCLUSION

This is the first case to highlight the clinical significance of this interaction, noting that patients taking enzalutamide may require approximately 30%-50% adjustment in their warfarin dosage to maintain a therapeutic INR.

Bleeding heart: a case of spontaneous hemopericardium and tamponade in a hyperthyroid patient on warfarin

We describe the case of an 81-year-old female, diagnosed with hyperthyroidism-related atrial fibrillation. Given her CHA2DS2VASc score of 3, she was started on warfarin for stroke prevention. One month later, she was admitted with cardiac tamponade. This tamponade was suspected to be secondary to hemopericardium, based on the elevated international normalized ratio (INR), drop in haemoglobin and the radiodensity (55 HU) of the pericardial effusion on CT. The patient was a Jehovah's witness who therefore initially refused measures for reversing coagulopathy. Given her coagulopathy and absence of imminent haemodynamic compromise, pericardiocentesis was deferred. Unfortunately, 1 day later, the patient deteriorated rapidly. By the time pericardiocentesis was performed and factor VIIa administered, the patient had already started developing multiple organ failure. She developed cardiac arrest and died 3 days after her admission. Only 10 cases of hemopericardium attributable to warfarin have previously been reported. In this report, we review the literature and also describe how hyperthyroidism most likely predisposed our patient to bleeding complications from warfarin.