Interventional neuroradiology (INR) has been a rapidly expanding and advancing clinical area during the past few decades. As the complexity and diversity of INR procedures increases, the demand for anesthesia also increases. Anesthesia for interventional neuroradiology is a challenge for the anesthesiologist due to the unfamiliar working environment which the anesthesiologist must consider, as well as the unique neuro-interventional components. This review provides an overview of the anesthetic options and specific consideration of the anesthesia requirements for each procedure. We also introduce the anesthetic management for interventional neuroradiology performed in our medical institution.
Anesthesia ; International Normalized Ratio

BACKGROUND AND OBJECTIVES: To evaluate the accuracy and the clinical utility of the Coaguchek(R) XS, a portable point-of-care coagulometer, compared to standard laboratory methods in Korean patients. SUBJECTS AND METHODS: We included 107 patients with atrial fibrillation on long-term oral warfarin therapy. The prothrombin time as expressed by the international normalized ratio (INR) was measured by the portable Coaguchek(R) XS system as well as standard laboratory methods. Agreement between the two methods was defined as a difference of less than 0.3 between the INR values. RESULTS: The INR determined by the portable Coaguchek(R) XS had excellent correlation with the values obtained by standard methods (r=0.984, p<0.01). The INR determined by the portable Coaguchek(R) XS tended to be high among the high INR group values (standard INR>3.0). There was a 91.6% agreement between the two methods. Only nine cases (8.4%) had a difference of more than 0.3; this was mainly noted in the high INR group. CONCLUSION: The portable self-testing of the INR by the Coaguchek(R) XS might be a reliable alternative to hospital based laboratory testing in Korean patients.
Atrial Fibrillation ; Humans ; International Normalized Ratio ; Prothrombin Time ; Warfarin

BACKGROUND: In order to achieve a maintenance level and to prevent hemorrhagic complications, regular monitoring of the INR is mandatory for patients on oral anticoagulation therapy (OAT). A point-of-care instrument for INR monitoring is convenient for users, but the accuracy of the results has been controversial, and so this calls for exact evaluation of the point-of-care instrument that is used for INR monitoring. METHODS: From Aug 2007 through Feb 2008, 85 patients on OAT among the all the patients who were admitted to Soonchunhyang University Bucheon Hospital were involved in this study. Parallel measurements of the PT INR were performed using a CoaguChek-XS and, a CA-7000 laboratory reference instrument and the results were analyzed. In addition, the patients' clinical data, including the diagnosis and the frequency and interval of the INR measurements, were also analyzed. RESULTS: Of the 85 patients, 25 were admitted more than once to undergo INR testing and the mean interval between testing was 8.6 weeks with 39% and 38% of the tests being less than INR 2 units with using the CoaguChek-XS and the reference method, respectively. The coefficients of variation of CoaguChek-XS were 4.50 and 2.45 for the high and low INR patients, respectively. An excellent correlation was found between the two methods with a R2 of 0.966 (p<0.001). Through Bland-Altman analysis, the mean INR difference between the two methods was 0.13 with the limit of agreement being -0.47 +0.72 with a 95% confidence interval. CoaguChek-XS was shown to overestimate the INR value for patients with an increasing INR, as compared to the reference method. CONCLUSION: CoaguChek-XS demonstrated great precision and accuracy for patients on OAT when compared to the laboratory INR results. Accordingly, the instrument should help to monitor the INR in the patients on OAT.
Avena ; Humans ; International Normalized Ratio ; Organothiophosphorus Compounds ; Prothrombin ; Prothrombin Time

BACKGROUND: We investigated changes in the International Normalized Ratio (INR) and its measurement interval in patients with thromboembolic events who were treated by low intensity anticoagulation therapy after isolated mechanical aortic valve replacement. MATERIALS AND METHODS: Seventy-seven patients who underwent surgery from June 1990 to September 2006 were enrolled in the study and observed until August 2008. The patients were followed up at 4~8 week intervals and their warfarin (Coumadin)(R) dosage was adjusted aiming for a target range of INR 1.5~2.5. The rate of thromboembolic events was obtained. Changes in the mean INR and INR measurement interval were comparatively analyzed between the normal group (event free group, N=52) who had no anticoagulation-related complications and the thromboembolic group (N=10). Hospital records were reviewed retrospectively. RESULTS: The observation period was 666.75 patient-years. Thromboembolic events occurred in 10 patients. The linearized occurrence rate of thromboembolism was 1.50%/patient-years. Actuarial thromboembolism-free rates were 97.10+/-2.02% at 5 years, 84.30+/-5.22% at 10 years, and 67.44+/-12.14% at 15 years. The percentages of INR within the target range and mean INR were not statistically significantly different for the normal and thromboembolic groups. However, the mean INR during the segmented period just before the events showed a significantly lower level in the thromboembolic group (during a 4 month period: normal group, 1.86+/-0.14 vs. thromboembolic group, 1.50+/-0.28, p<0.001). The mean intervals of INR measurement during the whole observation period showed no significant differences between groups, but in the segmented period just before the events, the interval was significantly longer in thromboembolic group (during a 6 month period: normal group, 49.04+/-9.47 days vs. thromboembolic group, 65.89+/-44.88 days, p<0.01). CONCLUSION: To prevent the occurrence of thromboembolic events in patients who receive isolated aortic valve replacement and low intensity anticoagulation therapy, we suggest that it would be safe to maintain an INR level above 1.8 and to measure the INR at least every 7~8 weeks.
Aortic Valve ; Hospital Records ; Humans ; International Normalized Ratio ; Thromboembolism ; Warfarin

Although traditionally fresh frozen plasma (FFP) has been the product of choice for reversing a significant coagulopathy, the modern blood bank will have several different plasma preparations which should all be equally efficacious in reversing a significant coagulopathy or arresting coagulopathic bleeding. Emerging evidence suggests that for a stable patient, transfusing plasma for an INR< or =1.5 does not confer a hemostatic benefit while unnecessarily exposing the patient to the risks associated with plasma transfusion. This review will discuss the various plasma products that are available and present some of the current literature on the clinical uses of plasma.
Blood Banks ; Hemorrhage ; Humans ; International Normalized Ratio ; Plasma

Hemothorax in a patient on anticoagulant therapy for atrial fibrillation after blunt trauma is not an uncommon event. However, massive hemothorax in such a patient with an extremely uncontrolled and high international normalized ratio (INR) may pose a serious dilemma. We report a case of a patient under anticoagulant therapy for atrial fibrillation who underwent an emergent thoracotomy for massive hemothorax with an INR of 9.57.
Atrial Fibrillation ; Hemothorax ; Humans ; International Normalized Ratio ; Thoracotomy

BACKGROUND AND OBJECTIVES: Anticoagulation with vitamin K antagonists (VKAs) such as warfarin provides effective stroke prophylaxis in patients with atrial fibrillation (AF). We conducted a large multicenter survey of Korean patients with AF to determine trends in VKA use. SUBJECTS AND METHODS: Eligible patients were adults with AF that had been prescribed VKAs. Medical records from a total of 5616 patients {mean age 63.6+/-12.2 years, male 3150 (56.1%)} in 27 hospitals from Jan. 2001 to Oct. 2007 were reviewed. RESULTS: The mean international normalized ratio (INR) was 2.04+/-0.64, and mean dosage of VKA was 3.66+/-1.50 mg. Individuals in their sixties (1852 patients) accounted for about one third of patients studied. As patients grew older, INR increased and VKA dosage decreased. The dosage of VKA in male patients was larger than that in females for all ages. A total of 2146 (42.4%) patients had an INR of 2-3, and less than 40% patients in their sixties had an INR within optimal range. The dosage of oral anticoagulant for optimal INR level was 3.71 mg. CONCLUSION: In this study, less than half of the Korean patients with AF on VKA reached the therapeutic range of INR. Mean dosage of VKA was 3.66+/-1.50 mg, and the dosage of oral anticoagulant for optimal INR level was 3.71 mg, which decreased with age.
Adult ; Anticoagulants ; Atrial Fibrillation ; Female ; Humans ; International Normalized Ratio ; Male ; Medical Records ; Stroke ; Vitamin K ; Warfarin

BACKGROUND: Coagulation studies are affected by the reagents and coagulometers that are used in the tests and it is therefore essential to compare the results within a peer group that uses the same reagents and coagulometer for an external quality control program. Because the domestic quality control program encompasses many different groups using different reagents and coagulometers, no comparison has been made among peer groups. Therefore, the authors performed a quality control program using in-house lyophilized plasma in a selected peer group. METHODS: Prothrombin times (PT) and activated partial thromboplastin times (aPTT) were tested using in-house normal and oral anticoagulant lyophilized plasma; the tests were performed for 50 consecutive days in four hospitals that were using the same coagulometer. The same PT reagents were used in all four hospitals. The international sensitivity index (ISI) was 1.32 for three hospitals and 1.47 for one hospital. Three hospitals used the same aPTT reagent. RESULTS: After lyophilization, there was no change in the PT results, but aPTT results were greatly prolonged. At four hospitals, the average international normalized ratio (INR) of normal lyophilized plasma was 0.94, 0.94, 0.95, and 0.82, while the average INR of oral anticoagulant lyophilized plasma was 2.18, 2.28, 2.21, and 1.87. The mean normal PT (MNPT) of three hospitals with ISI of 1.32 were 12.4s, 11.2s, and 12.3s, while the MNPT of one hospital with ISI of 1.47 was 12.5s. Average aPTT of normal plasma were 32.1s, 45.9s, 44.7s, and 44.3s while that of the oral anticoagulant plasma were 42.6s, 61.3s, 57.8s, and 55.6s. CONCLUSIONS: Since there are a great deal of difference in the results of coagulation study among the hospitals using the same reagents and coagulometers, it is utmost necessary to enforce a national level coagulation study quality control program in order to adopt proper oral anticoagulation therapy.
Freeze Drying ; Indicators and Reagents ; International Normalized Ratio ; Peer Group* ; Plasma ; Prothrombin Time ; Quality Control* ; Thromboplastin

This study aimed to explore the correlation between usual vitamin K intake and response to anticoagulant therapy among patients under warfarin therapy. We conducted a retrospective survey of patients (n = 50) on continuous warfarin therapy. Clinical information and laboratory parameters were sourced from medical records. Anticoagulant effect was evaluated by using the percent time in therapeutic range (TTR) and the coefficient of variation (CV) of International normalized ratio (INR). Dietary vitamin K intake was assessed using a semi-quantitative food frequency questionnaire that has been developed for the purpose of assessing dietary intake of vitamin K. A total of 50 patients aged between 21 and 87 years were included in the study. The mean vitamin K intake was 262.8 +/- 165.2 microg/day. Study subjects were divided into tertiles according to their usual vitamin K intake. The proportion of men was significantly higher in second and third tertile than first tertile (p = 0.028). The mean percent TTR was 38.4 +/- 28.4% and CV of INR was 31.8 +/- 11.8%. Long-term warfarin therapy group (> or = 3 years) had a higher percentage of TTR as compared to the control group (< 3 years) (p = 0.046). No statistically significant correlation was found between usual vitamin K intake and percent TTR (p > 0.05). In conclusion, no significant association was observed between usual vitamin K intake and anticoagulant effects. Further studies are required to consider inter-individual variability of vitamin K intake. Development of assessment tools to measure inter-individual variability of vitamin K intake might be helpful.
Humans ; International Normalized Ratio ; Male ; Medical Records ; Retrospective Studies ; Vitamin K* ; Vitamins* ; Warfarin*

BACKGROUND AND PURPOSE: The quality of anticoagulation is critical for ensuring the benefit of warfarin, but this has been less well studied in Korean ischemic stroke patients with atrial fibrillation (AF). METHODS: This study retrospectively analyzed the data of patients who had an AF-related ischemic stroke and were treated with long-term warfarin therapy in 16 Korean centers. The quality of warfarin therapy was primarily assessed by the time in therapeutic range [TTR; international normalized ratio (INR), 2.0–3.0] and additionally by the proportion of INR values within the therapeutic range. RESULTS: The long-term warfarin-treated cohort comprised 1,230 patients. They were aged 70.1±9.7 years (mean±SD), 42.5% were female, and their CHA₂DS₂-VASc score was 4.75±1.41. The TTR analysis included 33,941 INR measurements for 27,487 months: per patients, 27.6 (SD, 22.4) INR measurements for 22.4 (SD, 12.9) months. The mean TTR of individual patients was 49.1% (95% confidence interval, 47.9–50.3%), and the TTR quartiles were <34.5, 34.5–49.1, 49.1–64.5%, and >64.5%. None of the 16 centers achieved a mean TTR of >60%. Of all INR measurements, 44.6% were within the therapeutic range, 41.7% were <2.0, and 13.7% were >3.0. CONCLUSIONS: In Korean ischemic stroke patients who had AF, the quality of warfarin therapy was low and might be inadequate to effectively prevent recurrent stroke or systemic embolism.
Atrial Fibrillation* ; Cohort Studies ; Embolism ; Female ; Humans ; International Normalized Ratio ; Observational Study* ; Retrospective Studies* ; Stroke* ; Warfarin*