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Introduction: Anticoagulation with warfarin affects approximately 140,000 post-cardiac surgery patients every year, yet there remains limited published data in this patient population. Dosing remains highly variable due to intrinsic risk factors that plague cardiac surgery candidates and a lack of diverse literature that can be applied to those who have undergone a cardiac surgery alternative to heart valve replacement (HVR). In the present study, our aim was to compare the warfarin requirements between HVR and non-HVR patients., Methods: This was a single-center, retrospective study of post-cardiac surgery patients initiated on warfarin at Mayo Clinic Hospital, Rochester, from January 1st, 2013 to October 31st, 2016. The primary outcome was the maintenance warfarin dose at the earliest of discharge or warfarin day 10 between patients with HVR and non-HVR cardiac surgeries., Results: A total of 683 patients were assessed during the study period: 408 in the HVR group and 275 in the non-HVR group. The mean warfarin maintenance doses in the HVR and non-HVR groups were 2.55 mg [standard deviation (SD) 1.52] and 2.43 mg (SD 1.21), respectively (adjusted p = 0.65). A multivariable analysis was performed to adjust for gender, age, body mass index and drug interactions., Conclusions: This was the largest study to evaluate warfarin dose requirements in post-cardiac surgery patients and is the first to compare warfarin requirements between HVR and non-HVR patients during the immediate post-operative period. Both groups had similar warfarin requirements, which supports expanding the initial warfarin dosing recommendations of the 9th edition Chest guideline to include non-HVR patients as well as HVR patients.

To reliably assess quality, a standardized electronic approach is needed to identify bleeding events. The study aims were the following: (1) clinically validate an electronic health record-based algorithm for bleeding and (2) assess interrater results to determine validity and reliability. Data were analyzed before and after implementation of a pharmacist-managed warfarin protocol. Bleeding was based on ≥2 of 3 criteria: (1) diagnosis indicating bleeding, (2) lab value decrease suggesting bleeding, and (3) blood product use. All suspected bleeds (234) and a sample (58) not meeting criteria were compared with clinical review. There were 234 bleeding cases identified electronically. Reviewer agreement was 78.2% (κ = 0.565). Algorithm sensitivity was 93.9% and positive predictive value 46.2%. Algorithm identification was least accurate for those with only 2 criteria but good for those with all criteria. This study supports using multiple electronic criteria to identify bleeding events. However, cases having exactly 2 criteria may require manual review for validation.

Study Objective: To identify specific risk factors for excessive anticoagulation, defined as an international normalized ratio (INR) higher than 5, in hospitalized adults receiving warfarin therapy using a pharmacist-managed dosing protocol., Design: Retrospective nested case-control study., Setting: Large academic tertiary care medical center., Patients: Hospitalized nonsurgical patients 18 years or older who received at least one dose of warfarin according to the pharmacist-managed protocol from January 1, 2009, to January 31, 2012, were included. Patients who experienced an INR higher than 5 were designated as case patients; those who received warfarin for at least as many days as the case patients but who did not experience an INR more than 5 were deemed control patients. Controls were matched to cases in a 2:1 ratio by age, sex, INR goal, and type of warfarin therapy (new start or continuation)., Measurements and Main Results: A total of 87 case patients were matched to 174 controls. Ten different hypothesized risk factors were examined. Two variables, severity of illness score (odds ratio [OR] 4.89, p<0.001) and poor nutritional status (OR 4.27, p<0.001), demonstrated strong independent associations with risk of excessive anticoagulation. Administration of interacting drugs that highly potentiate warfarin's effect (OR 2.26, p=0.011) and concurrent diarrheal illness (OR 4.75, p<0.001) also displayed a statistically significant risk for excessive anticoagulation., Conclusion: Even in a highly standardized system for warfarin dosing by a pharmacist-managed protocol, higher disease severity and poor nutritional status placed hospitalized patients at greater risk of experiencing excessive anticoagulation. In addition, administration of interacting drugs that highly potentiate warfarin's effect or the occurrence of diarrheal illness may predict increased risk., (© 2013 Pharmacotherapy Publications, Inc.)