No abstract

Observational evidence suggests that the endovascular approach for revascularization in patients with CMI may offer better early outcomes than open surgery, although this effect may not be durable. Long-term mortality appears to be similar.

Summary. Background: While a considerable amount is known about which patient-level factors predict poor anticoagulation control with warfarin, measured by percent time in therapeutic range (TTR), less is known about predictors of time above or below target. Objective: To identify predictors of different patterns of international normalized ratio (INR) values that account for poor control, including 'erratic' patterns, where more time is spent both above and below INR target, and unidirectional patterns, where time out of range is predominantly in one direction (low or high). Methods: We studied 103 897 patients receiving warfarin with a target INR of 2-3 from 100 Veterans Health Administration sites between October 2006 and September 2008. Our outcomes were percent time above and below the target range. Predictors included patients' demographics, comorbidities, and other clinical data. Results: Predictors of erratic patterns included alcohol abuse (5.2% more time below and 3.7% more time above, P < 0.001 for all results), taking > 16 medications (4.6% more time below and 1.8% more time above compared to taking seven or fewer medications), and four or more hospitalizations during the study (6.6% more time below and 2% more time above compared to no hospitalization). In contrast, predictors like cancer, non-alcohol drug abuse, dementia, and bipolar disorder were associated with more time below the target range (3.4%, 5.2%, 2.6%, and 3.2%, respectively) and less (or similar) time above range. Conclusion: Different patientlevel factors predicted unidirectional below-target and 'erratic' patterns of INR control. Distinct interventions are necessary to address these two separate pathways to poor anticoagulation.

TTR and INR variabilities measure different characteristics of anticoagulation control.12 TTR reflects the achievement of appropriate intensity, and not necessarily the stability, of the anticoagulation regimen. Conversely, INR variability measures stability, but not intensity, of anticoagulation. One approach to strengthen our prediction about warfarin adverse events would be to combine these measures. Whether the use of both measures jointly will improve risk stratification for ultimate outcomes of interest, such as thrombotic events, bleeding events, or mortality, requires further exploration.Our study aimed to test whether using both measures will more accurately assign risk of warfarin therapy complications, such as ischemic strokes and major bleeding, among patients with atrial fibrillation. Improving intermediate outcome measures in anticoagulation will allow a more accurate reflection of the true quality of care received by patients.Background-Among patients receiving warfarin, percent time in therapeutic range (TTR) and international normalized ratio (INR) variability predict adverse events individually. Here, we examined what is added to the prediction of adverse events by using both measures together. Methods and Results-We included 40 404 patients anticoagulated for atrial fibrillation, aged 65+, within the Veterans Health Administration. TTR and log-transformed INR variability were calculated for each patient. Our study outcomes were ischemic stroke and major bleeding, defined using International Classification of Diseases-9 codes. We estimated the hazard ratios (HRs) for the study outcomes using 3 nested Cox regression models, including (1) TTR or log INR variability separately; (2) TTR and log INR variability together; and (3) both predictors together plus an interaction term. We divided TTR into 3 categories (high, >70%; moderate, 50% to 70%; low, <50%) and log INR variability into 2 categories (stable and unstable). The reference groups high TTR and stable anticoagulation each denote good control. Higher log INR variability (ie, unstable control) predicted ischemic stroke (HR=1.45, P<0.001) and major bleeding (HR=1.57, P<0.001) independently, regardless of TTR levels. Our model with interaction terms showed that High log INR variability predicted a significantly higher risk for ischemic stroke and major bleeding compared with low log INR variability, at moderate TTR levels (HR= 1.27 and HR=1.29, respectively) and at high TTR levels (HR=1.55 and HR=1.56, respectively), but not at low TTR levels. Conclusions-Unstable anticoagulation predicts warfarin adverse effects independent of TTR. Moreover, knowledge about anticoagulation stability further stratifies the risk for adverse events at given levels of TTR. (Circ Cardiovasc Qual Outcomes. 2014;7:664-669.)Key Words: anticoagulants ◼ healthcare quality ◼ international normalized ratio ◼ outcome ◼ warfarin