Nallamothu, Brahmajee K.

Background: Stroke prevention using warfarin is challenging in AF patients with CKD, due to high bleeding risk and difficulties in the INR control. NOACs provide alternative options, but all have greater degrees of renal clearance. This study aimed to compare the outcomes of apixaban, dabigatran, rivaroxaban, and warfarin across the range of kidney function in patients with AF. Methods: Using a US administrative database including private insurance or Medicare Advantage patients with linked claims and laboratory data, we identified 34,569 new users of oral anticoagulants with AF and eGFR ≥15 between 10/1/2010-11/29/2017. Stabilized IPTW balanced four treatment groups on 66 baseline characteristics. The primary outcomes included stroke, major bleeding, and mortality. Weighted Cox proportional hazards models compared treatments in the overall population and in each eGFR subgroup, with mortality as a competing risk for stroke and major bleeding. Results: The proportion of patients using warfarin increased as the kidney function declined - 26.5%, 30.4%, 34.6%, 40.5%, and 55.0% of patients were prescribed warfarin in eGFR ≥90, 60-90, 45-60, 30-45, 15-30 groups, respectively. In comparison to warfarin, apixaban was associated with a lower risk of stroke, major bleeding, and mortality; dabigatran was associated with a similar risk of stroke, and a lower risk of major bleeding and mortality; rivaroxaban was associated with a lower risk of stroke, major bleeding, and mortality (Figure). When comparing one NOAC to another NOAC, apixaban and dabigatran were associated with a lower risk of major bleeding than rivaroxaban (HR 0.61 [0.51-0.73], p<0.001 for apixaban versus rivaroxaban; HR 0.67 [0.50-0.90], p=0.007 for dabigatran versus rivaroxaban); dabigatran was associated with a higher risk of stroke than apixaban (HR 1.65 [1.11-2.46], p=0.01); there was no difference in mortality. There was no significant interaction between treatment and eGFR categories for any outcome, but the number of patients with low eGFR was small. Conclusions: In practice, relative to warfarin, NOACs are progressively less commonly used with increasing degree of renal dysfunction. However, each NOAC was consistently associated with at least equivalent effectiveness and safety compared with warfarin across the range of kidney function.

Background: Patients with end-stage kidney disease (ESKD) on dialysis were excluded from clinical trials of direct oral anticoagulants for atrial fibrillation (AF). Recent data have raised concerns regarding the safety of dabigatran and rivaroxaban, but apixaban has not been evaluated despite current labeling supporting its use in this population. The goal of this study was to determine patterns of apixaban use and its associated outcomes in dialysis-dependent patients with ESKD and AF. Methods: We performed a retrospective cohort study of Medicare beneficiaries included in the United States Renal Data System (October 2010 to December 2015). Eligible patients were those with ESKD and AF undergoing dialysis who initiated treatment with an oral anticoagulant. Because of the small number of dabigatran and rivaroxaban users, outcomes were only assessed in patients treated with apixaban or warfarin. Apixaban and warfarin patients were matched (1:3) based on prognostic score. Differences between groups in survival free of stroke or systemic embolism, major bleeding, gastrointestinal bleeding, intracranial bleeding, and death were assessed using Kaplan–Meier analyses. Hazard ratios (HRs) and 95% CIs were derived from Cox regression analyses. Results: The study population consisted of 25 523 patients (45.7% women; 68.2±11.9 years of age), including 2351 patients on apixaban and 23 172 patients on warfarin. An annual increase in apixaban prescriptions was observed after its marketing approval at the end of 2012, such that 26.6% of new anticoagulant prescriptions in 2015 were for apixaban. In matched cohorts, there was no difference in the risks of stroke/systemic embolism between apixaban and warfarin (HR, 0.88; 95% CI, 0.69–1.12; P =0.29), but apixaban was associated with a significantly lower risk of major bleeding (HR, 0.72; 95% CI, 0.59–0.87; P <0.001). In sensitivity analyses, standard-dose apixaban (5 mg twice a day; n=1034) was associated with significantly lower risks of stroke/systemic embolism and death as compared with either reduced-dose apixaban (2.5 mg twice a day; n=1317; HR, 0.61; 95% CI, 0.37–0.98; P =0.04 for stroke/systemic embolism; HR, 0.64; 95% CI, 0.45–0.92; P =0.01 for death) or warfarin (HR, 0.64; 95% CI, 0.42–0.97; P =0.04 for stroke/systemic embolism; HR, 0.63; 95% CI, 0.46–0.85; P =0.003 for death). Conclusions: Among patients with ESKD and AF on dialysis, apixaban use may be associated with a lower risk of major bleeding compared with warfarin, with a standard 5 mg twice a day dose also associated with reductions in thromboembolic and mortality risk.

ABSTRACTObjectivesIdentifying the distributions and determinants of fluoroscopy time for invasive coronary angiography (ICA) and percutaneous coronary intervention (PCI).BackgroundICA and PCI are significant contributors to radiation exposure from medical imaging in the US. Fluoroscopy time is a potentially modifiable determinant of radiation exposure for these procedures, but has not been well characterized in contemporary practice.MethodsWe evaluated the distribution of fluoroscopy time in patients undergoing ICA and/or PCI in the CathPCI Registry®, stratifying patients by numerous clinical scenarios. Hierarchical models were used to determine patient, procedure, operator and hospital‐level factors associated with fluoroscopy time for these procedures.ResultsOur study included a total of 3,295,348 ICA and PCI procedures performed by 9,600 operators from January 2005 through June 2009. There was wide variation in fluoroscopy times for these procedures with median [IQR] fluoroscopy times of 2.6 [1.7–4.5] minutes for ICA, 6.7 [4.2–10.8] minutes for ICA in patients with prior coronary artery bypass grafting (CABG), 10.1 [6.0–17.4] minutes for PCI, 10.7 [7.0–16.9] minutes for PCI with ICA, and 16.0 [10.6–24.0] minutes for PCI and ICA in patients with prior CABG. Prolonged fluoroscopy times (>30 minutes) were rare for ICA, but occurred in 6.7% of PCIs and 14.7% of PCIs in patients with prior CABG. After accounting for patient characteristics and procedure complexity, operator and hospital‐level factors explained nearly 20% of the variation in fluoroscopy time.ConclusionsFluoroscopy times vary widely during ICA and PCI with operator and hospital‐level factors contributing substantially to these differences. A better understanding of potentially modifiable sources of this variation will elucidate opportunities for enhancing the radiation safety of these procedures. © 2013 Wiley Periodicals, Inc.

Background— Measurement of hospital quality has traditionally focused on processes of care and postprocedure outcomes. Appropriateness measures for percutaneous coronary intervention (PCI) assess quality as it relates to patient selection and the decision to perform PCI. The association between patient selection for PCI and processes of care and postprocedural outcomes is unknown. Methods and Results— We included 203 531 patients undergoing nonacute (elective) PCI from 779 hospitals participating in the National Cardiovascular Data Registry (NCDR) CathPCI Registry between July 2009 and April 2011. We examined the association between a hospital's proportion of nonacute PCIs categorized as inappropriate by the 2009 Appropriate Use Criteria (AUC) for Coronary Revascularization and in-hospital mortality, bleeding complications, and use of optimal guideline-directed medical therapy at discharge (ie, aspirin, thienopyridines, and statins). When categorized as hospital tertiles, the range of inappropriate PCI was 0.0% to 8.1% in the lowest tertile, 8.1% to 15.2% in the middle tertile, and 15.2% to 58.6% in the highest tertile. Compared with lowest-tertile hospitals, mortality was not significantly different at middle-tertile (adjusted odds ratio [OR], 0.93; 95% confidence interval [CI], 0.73–1.19) or highest-tertile hospitals (OR, 1.12; 95% CI, 0.88–1.43; P =0.35 for differences between tertiles). Similarly, risk-adjusted bleeding did not vary significantly (middle-tertile OR, 1.13; 95% CI, 1.02–1.16; highest-tertile OR, 1.02; 95% CI, 0.91–1.16; P =0.07 for differences between tertiles) nor did use of optimal medical therapy at discharge (85.3% versus 85.7% versus 85.2%; P =0.58). Conclusions— In a national cohort of nonacute PCIs, a hospital's proportion of inappropriate PCIs was not associated with in-hospital mortality, bleeding, or medical therapy at discharge. This suggests PCI appropriateness measures aspects of hospital PCI quality that are independent of how well the procedure is performed. Therefore, PCI appropriateness and postprocedural outcomes are both important metrics to inform PCI quality.