We report a case of intolerance to warfarin dosing due to impaired drug metabolism in a patient with CYP2C9*3/*4. A 73-yr-old woman with atrial fibrilation was taking warfarin. She attained a high prothrombin time international normalized ratio (INR) at the standard doses during the induction of anticoagulation and extremely low dose of warfarin (6.5 mg/week) was finally chosen to reach the target INR. Genotyping for CYP2C9 revealed that this patient had a genotype CYP2C9*3/*4. This is the first Korean compound heterozygote for CYP2C9*3 and *4. This case suggests the clinical usefulness of pharmacogenetic testing for individualized dosage adjustments of warfarin.
Aged ; Anticoagulants/pharmacology ; Aryl Hydrocarbon Hydroxylases/*genetics ; Atrial Fibrillation/*drug therapy/*genetics ; Female ; *Genotype ; Heterozygote ; Humans ; International Normalized Ratio ; Pharmacogenetics ; Polymorphism, Genetic ; Prothrombin Time ; Warfarin/*pharmacology

OBJECTIVETo compared the therapeutic effect of a Chinese patent medicine Naoxintong Capsule (, NXT) and aspirin with adjusted-dose warfarin in Chinese elderly patients (over 65 years) with nonvalvular atrial fibrillation (NVAF) and genetic variants of vitamin K epoxide reductase (VKORC1), who are at high-risk of thromboembolism.

METHODSA total of 151 patients, with NVAF and AA genotype of VKORC1-1639 (a sensitive genotype to warfarin) and a CHADS-VASc clinical risk score of 2 or above, were chosen for this study. Patients were randomized into two groups and orally treated with a combination of aspirin (100 mg/day) and NXT (1.6 g thrice a day) or adjusted-dose warfarin [international normalized ratio 2.0-3.0). The primary end points including ischemic stroke and death as well as the secondary end points including hemorrhage events were followed up for at least 1 year.

RESULTSBaseline clinical data and the rates of primary end points were similar between groups. However, the rate of serious bleeding (secondary event) in the combination therapy group was lower than that in the adjusted-dose warfarin group (0% vs. 7.9%, odds ratio: 0.921, 95% confidence interval: 0.862-0.984, P=0.028).

CONCLUSIONSAspirin combined with NXT and warfarin displayed comparable rates of primary end point including ischemic stroke and all-cause death during the 1-year follow-up. However, as compared with warfarin, the combination therapy reduced the rate of serious bleeding. Therefore, aspirin combined with NXT might provide an alternative pharmacotherapy in preventing ischemic stroke for elderly patients with NAVF who cannot tolerate warfarin. (No. ChiCTR-TRC-13003596).

Aged ; Aspirin ; therapeutic use ; Atrial Fibrillation ; drug therapy ; enzymology ; genetics ; Base Sequence ; Capsules ; Drugs, Chinese Herbal ; therapeutic use ; Endpoint Determination ; Female ; Genetic Variation ; Humans ; Male ; Risk Factors ; Treatment Outcome ; Vitamin K Epoxide Reductases ; genetics ; Warfarin ; therapeutic use

OBJECTIVETo evaluate the effect of VKORC1, CYP2C9, GGCX, PROC, EPHX1 and CYP4F2 gene polymorphisms on Warfarin maintenance dose variation in Chinese Han Population.

METHODSFour hundred eighty-eight patients with prosthetic heart valves, atrial fibrillation or pulmonary thromboembolism and achieved stable Warfarin dose were enrolled. TaqMan probe or direct sequencing were used to genotype Y9VKORC1, CYP2C9, GGCX, EPHX1 and CYP4F2 gene polymorphisms. Demographic characteristics, stable therapeutic dose of Warfarin and concomitant medications were collected for all patients. The effect of VKORC1, CYP2C9, GGCX, PROC, EPHX1 and CYP4F2 gene polymorphisms, demographic characteristics and concomitant medications on Warfarin daily maintenance dose were analyzed with statistical method.

RESULTSVKORC1 and CYP2C9 gene polymorphisms could explain more than 50% Warfarin maintenance dose variation in recruited patients, while CYP4F2 gene polymorphisms could only explain 1%. GGCX, PROC and EPHX1 gene polymorphisms had no impact no Warfarin maintenance dose. VKORC1 and CYP2C9 gene polymorphisms have a greater impact on Warfarin maintenance dose compared with demographic characteristics and concomitant medications.

CONCLUSIONVKORC1 and CYP2C9 gene polymorphisms have a significant impact on Warfarin maintenance dose in Chinese Han population.

Adult ; Aged ; Aryl Hydrocarbon Hydroxylases ; genetics ; Asian Continental Ancestry Group ; ethnology ; genetics ; Atrial Fibrillation ; drug therapy ; ethnology ; genetics ; Cytochrome P-450 CYP2C9 ; Cytochrome P-450 Enzyme System ; genetics ; Cytochrome P450 Family 4 ; Dose-Response Relationship, Drug ; Epoxide Hydrolases ; genetics ; Female ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Protein C ; genetics ; Pulmonary Embolism ; drug therapy ; ethnology ; genetics ; Treatment Outcome ; Vitamin K Epoxide Reductases ; genetics ; Warfarin ; administration & dosage ; Young Adult

BACKGROUNDWe hypothesize that increased atrial oxidative stress and inflammation may play an important role in atrial nerve sprouting and heterogeneous sympathetic hyperinnervation during atrial fibrillation (AF). To test the hypothesis, we examined whether the antioxidant and anti-inflammatory treatment with probucol attenuates atrial autonomic remodeling in a canine model of AF produced by prolonged rapid right atrial pacing.

METHODSTwenty-one dogs were divided into a sham-operated group, a control group and a probucol group. Dogs in the control group and probucol group underwent right atrial pacing at 400 beats per minute for 6 weeks, and those in the probucol group received probucol 1 week before rapid atrial pacing until pacing stopped. After 6-week rapid atrial pacing, general properties including left atrial structure and function, atrial hemodynamics and the inducibility and duration of AF were measured in all the groups. Atrial oxidative stress markers and serum C-reactive protein (CRP) concentration were estimated. The degree of nerve sprouting and sympathetic innervation at the right atrial anterior wall (RAAW) and the left atrial anterior wall (LAAW) were quantified by immunohistochemistry, atrial norepinephrine contents were also detected. Atrial beta-nerve growth factor (beta-NGF) mRNA and protein expression at the RAAW and LAAW were assessed by real-time quantitative RT-PCR and Western blotting respectively.

RESULTSAtrial tachypacing induced significant nerve sprouting and heterogeneous sympathetic hyperinnervation, and the magnitude of nerve sprouting and hyperinnervation was higher in the RAAW than in the LAAW. Atrial beta-NGF mRNA and protein levels were significantly increased at the RAAW and LAAW, and the upregulation of beta-NGF expression was greater at the RAAW than at the LAAW in the control group. The beta-NGF protein level was positively correlated with the density of sympathetic nerves in all groups. Probucol decreased the increase of CRP concentration and attenuated atrial oxidative stress caused by atrial tachypacing. In addition, probucol could effectively inhibit atrial beta-NGF upregulation, significantly attenuate atrial nerve sprouting and heterogeneous sympathetic hyperinnervation, and dramatically reduce the inducibility and duration of AF.

CONCLUSIONSThe atrial over-expression of beta-NGF possibly caused by increased oxidative stress and inflammation may be the main mechanism underlying atrial autonomic remodeling during AF. Probucol attenuates atrial autonomic remodeling possibly by its antioxidant and anti-inflammatory actions.

Animals ; Antioxidants ; therapeutic use ; Atrial Fibrillation ; drug therapy ; Blotting, Western ; C-Reactive Protein ; metabolism ; Cardiac Pacing, Artificial ; adverse effects ; Disease Models, Animal ; Dogs ; Electrocardiography ; Female ; Heart Atria ; Immunohistochemistry ; Male ; Nerve Growth Factor ; genetics ; metabolism ; Norepinephrine ; metabolism ; Probucol ; therapeutic use ; Reverse Transcriptase Polymerase Chain Reaction