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Background: The longitudinal response to the COVID-19 vaccines among patients on hemodialysis with and without prior SARS-CoV-2 infection has not been well characterized. Methods: To guide vaccination strategies in patients on hemodialysis, it is critical to characterize the longevity and efficacy of the vaccine; therefore, we conducted a prospective single-center monthly antibody surveillance study between March 2021 and March 2022 to investigate the dynamic humoral response to a series of COVID-19 mRNA vaccines in patients on hemodialysis with and without prior SARS-CoV-2 infection. Monthly quantitative antibody testing was performed using the Beckman Coulter Access SARS-CoV-2 IgG Antibody Test©, which detects IgG antibodies targeting the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Results: This cohort of 30 participants (mean age: 61 ± 3 years) predominantly self-identified as African American (97%) and male (53%). Eight participants (27%) had recovered from COVID-19 (recovered) before the vaccine initiation. All participants received two vaccine doses, and 86.6% received a 6-month booster dose. Among patients naïve to COVID-19, the antibody positivity rate (APR) was 55% post-first-dose, 91% post-second-dose, 50% pre-booster at 6 months, 100% post-booster, and 89% at 6 months post-booster. Recovered patients sustained a consistent 100% APR throughout the year. The naïve patients demonstrated lower peak antibody levels post-second-dose than the recovered patients (17.9 ± 3.2 vs. 44.7 ± 5.6, p < 0.001). The peak antibody levels post-booster showed no significant difference between both groups (27.1 ± 3.9 vs. 37.9 ± 8.2, p = 0.20). Two naïve patients contracted COVID-19 during the follow-up period. Conclusions: The patients naïve to COVID-19 exhibited an attenuated and foreshortened antibody response following two doses of the mRNA vaccines compared with the recovered patients, who maintained 100% APR before the booster dose. The 6-month booster dose counteracted declining immunity and stimulated antibody responses in the naïve patients, even in previously non-responsive patients. This observation implies that different booster vaccination strategies might be required for COVID-19-naïve and -recovered patients. Post-vaccination antibody testing may serve as a valuable tool for guiding vaccination strategies. [ABSTRACT FROM AUTHOR]

Importance: Effective treatment of acute kidney injury (AKI) is predicated on timely diagnosis; however, the lag in the increase in serum creatinine levels after kidney injury may delay therapy initiation.Objective: To determine the derivation and validation of predictive models for AKI after cardiac surgery.Design, Setting, and Participants: Multivariable prediction models were derived based on a retrospective observational cohort of adult patients undergoing cardiac surgery between January 2000 and December 2019 from a US academic medical center (n = 58 526) and subsequently validated on an external cohort from 3 US community hospitals (n = 4734). The date of final follow-up was January 15, 2020.Exposures: Perioperative change in serum creatinine and postoperative blood urea nitrogen, serum sodium, potassium, bicarbonate, and albumin from the first metabolic panel after cardiac surgery.Main Outcomes and Measures: Area under the receiver-operating characteristic curve (AUC) and calibration measures for moderate to severe AKI, per Kidney Disease: Improving Global Outcomes (KDIGO), and AKI requiring dialysis prediction models within 72 hours and 14 days following surgery.Results: In a derivation cohort of 58 526 patients (median [IQR] age, 66 [56-74] years; 39 173 [67%] men; 51 503 [91%] White participants), the rates of moderate to severe AKI and AKIrequiring dialysis were 2674 (4.6%) and 868 (1.48%) within 72 hours and 3156 (5.4%) and 1018 (1.74%) within 14 days after surgery. The median (IQR) interval to first metabolic panel from conclusion of the surgical procedure was 10 (7-12) hours. In the derivation cohort, the metabolic panel-based models had excellent predictive discrimination for moderate to severe AKI within 72 hours (AUC, 0.876 [95% CI, 0.869-0.883]) and 14 days (AUC, 0.854 [95% CI, 0.850-0.861]) after the surgical procedure and for AKI requiring dialysis within 72 hours (AUC, 0.916 [95% CI, 0.907-0.926]) and 14 days (AUC, 0.900 [95% CI, 0.889-0.909]) after the surgical procedure. In the validation cohort of 4734 patients (median [IQR] age, 67 (60-74) years; 3361 [71%] men; 3977 [87%] White participants), the models for moderate to severe AKI after the surgical procedure showed AUCs of 0.860 (95% CI, 0.838-0.882) within 72 hours and 0.842 (95% CI, 0.820-0.865) within 14 days and the models for AKI requiring dialysis and 14 days had an AUC of 0.879 (95% CI, 0.840-0.918) within 72 hours and 0.873 (95% CI, 0.836-0.910) within 14 days after the surgical procedure. Calibration assessed by Spiegelhalter z test showed P >.05 indicating adequate calibration for both validation and derivation models.Conclusions and Relevance: Among patients undergoing cardiac surgery, a prediction model based on perioperative basic metabolic panel laboratory values demonstrated good predictive accuracy for moderate to severe acute kidney injury within 72 hours and 14 days after the surgical procedure. Further research is needed to determine whether use of the risk prediction tool improves clinical outcomes. [ABSTRACT FROM AUTHOR]

BackgroundAortic pulse wave velocity (PWV) is a measure of arterial stiffness and has proved useful in predicting cardiovascular morbidity and mortality in several populations of patients, including the healthy elderly, hypertensives and those with end-stage renal disease receiving hemodialysis. Little data exist characterizing aortic stiffness in patients with chronic kidney disease (CKD) who are not receiving dialysis, and in particular the effect of reduced kidney function on aortic PWV.MethodsWe performed measurements of aortic PWV in a cross-sectional cohort of participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study to determine factors which predict increased aortic PWV in CKD.ResultsPWV measurements were obtained in 2,564 participants. The tertiles of aortic PWV (adjusted for waist circumference) were <7.7 m/s, 7.7–10.2 m/s, and >10.2 m/s with an overall mean (± s.d.) value of 9.48 ± 3.03 m/s (95% confidence interval = 9.35–9.61 m/s). Multivariable regression identified significant independent positive associations of age, blood glucose concentrations, race, waist circumference, mean arterial blood pressure, gender, and presence of diabetes with aortic PWV and a significant negative association with the level of kidney function.ConclusionsThe large size of this unique cohort, and the targeted enrollment of CKD participants provides an ideal situation to study the role of reduced kidney function as a determinant of arterial stiffness. Arterial stiffness may be a significant component of the enhanced cardiovascular risk associated with kidney failure.American Journal of Hypertension 2010; doi:10.1038/ajh.2009.240 [ABSTRACT FROM AUTHOR]

Increased vascular stiffness is an established risk marker of cardiovascular diseases (CVD) in adults with end-stage renal disease, but its role in pediatric patients remains to be defined. We prospectively examined arterial compliances of adolescents and young adults on hemodialysis (HD) using diastolic pulse wave analysis (DPWA). Each of the ten HD patients (age 17.3 ± 3.9 years; mean ± SD) had two DPWA tests within a three-week time period. DPWA measurement was performed before and hourly until the end of three-hour HD. Pre-HD large artery elasticity index (LAEI) was reduced in one patient and small artery elasticity index (SAEI) was reduced in another. Neither patient was hypertensive. Eight other patients had a reduction in both LAEI and SAEI. Among them, six patients had systolic and/or diastolic hypertension, and the other two were normotensive. Serum phosphorus correlated positively with stroke volume and cardiac output indices and negatively with SAEI. The reduction in BP during HD correlated with the amount of fluid removal. LAEI and SAEI were unchanged during HD. In conclusion, the reduction in LAEI and/or SAEI was observed in four normotensive patients, suggesting hypertension was not the only contributing factor for the reduced arterial compliances in our patients. The association between SAEI and serum phosphorus suggests that SAEI derived from DPWA can potentially be an early non-invasive, operator-independent, and volume-independent marker of CVD in adolescents and young adults receiving HD. Longitudinal studies with a larger sample size are needed to confirm our observation and speculation. [ABSTRACT FROM AUTHOR]

Background/Aims: Although maintenance of iron stores by intravenous iron infusion has become increasingly common in chronic hemodialysis patients, the effects of intravenous iron on blood pressure are not clear. Methods: In 52 mostly African-American patients in an urban setting, we reviewed blood pressure data over the course of hemodialysis on days that intravenous iron was administered and on control days. Results: The drop in blood pressure from the beginning to the end of hemodialysis was more pronounced when iron was not administered (9.9 ± 1.2 mm Hg) compared to when iron was administered (4.1 ± 1.7 mm Hg; p < 0.01). In a subset of chronic hemodialysis patients, blood pressure was actually higher at the end of hemodialysis compared to at the onset (9.6% of control hemodialysis sessions and 32.7% of sessions in which iron was administered; p < 0.01). The incidence of intra-dialytic hypotension and related symptoms was similar on iron and non-iron days. Conclusion: Intravenous iron therapy, well entrenched in clinical practice for the treatment of the anemia of end-stage renal disease, may reduce the incidence and magnitude of post-dialytic hypotension. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Cardiovascular responses to hemodialysis have been characterized by invasive monitoring techniques. These techniques are not feasible for evaluation of hemodynamic status during dialysis in the outpatient setting. In this study, we used pulse waveform analysis (PWA), a noninvasive tool designed for the ambulatory setting, to assess hemodynamic responses of dialysis treatments in 27 stable subjects with end-stage renal disease receiving chronic hemodialysis. In our population, systolic, diastolic, and pulse pressures were unaffected by dialysis despite the mean fluid removal of 3.0 ± 0.2 kg. However, using PWA, we observed that stroke volume and cardiac output progressively declined by 17% to 19% (P < .001) with a concomitant increase in systemic vascular resistance by 22% from 1654 ± 88 to 2020 ± 121 dynes · sec · cm−5 (P < .001). Also, we observed a significant reduction in small artery compliance from 4.7 ± 0.5 to 3.3 ± 0.4 mL · mm Hg−1 · 100 (P = .01), whereas large artery elasticity was unaffected. These findings suggest that changes in small artery vascular compliance contribute to the elevation in systemic vascular resistance during dialysis. This study confirms that hemodynamic adaptations to the dialysis procedure can be detected using PWA and are consistent with data obtained by invasive monitoring techniques. Furthermore, the observed reduction in vascular compliance in response to dialysis may contribute to the high cardiovascular risk in patients undergoing chronic hemodialysis therapy. [Copyright &y& Elsevier]

Background: There are no randomized data evaluating the safety or efficacy of apixaban for stroke prevention in patients with end-stage kidney disease on hemodialysis and with atrial fibrillation (AF).Methods: The RENAL-AF trial (Renal Hemodialysis Patients Allocated Apixaban Versus Warfarin in Atrial Fibrillation) was a prospective, randomized, open-label, blinded-outcome evaluation (PROBE) of apixaban versus warfarin in patients receiving hemodialysis with AF and a CHA2DS2-VASc score ≥2. Patients were randomly assigned 1:1 to 5 mg of apixaban twice daily (2.5 mg twice daily for patients ≥80 years of age, weight ≤60 kg, or both) or dose-adjusted warfarin. The primary outcome was time to major or clinically relevant nonmajor bleeding. Secondary outcomes included stroke, mortality, and apixaban pharmacokinetics. Pharmacokinetic sampling was day 1, day 3, and month 1.Results: From January 2017 through January 2019, 154 patients were randomly assigned to apixaban (n=82) or warfarin (n=72). The trial stopped prematurely because of enrollment challenges. Time in therapeutic range (international normalized ratio, 2.0-3.0) for warfarin-treated patients was 44% (interquartile range, 23%-59%). The 1-year rates for major or clinically relevant nonmajor bleeding were 32% and 26% in apixaban and warfarin groups, respectively (hazard ratio, 1.20 [95% CI, 0.63-2.30]), whereas 1-year rates for stroke or systemic embolism were 3.0% and 3.3% in apixaban and warfarin groups, respectively. Death was the most common major event in the apixaban (21 patients [26%]) and warfarin (13 patients [18%]) arms. The pharmacokinetic substudy enrolled the target 50 patients. Median steady-state 12-hour area under the curve was 2475 ng/mL×h (10th to 90th percentiles, 1342-3285) for 5 mg of apixaban twice daily and 1269 ng/mL×h (10th to 90th percentiles, 615-1946) for 2.5 mg of apixaban twice daily. There was substantial overlap between minimum apixaban blood concentration, 12-hour area under the curve, and maximum apixaban blood concentration for patients with and without a major or clinically relevant nonmajor bleeding event.Conclusions: There was inadequate power to draw any conclusion regarding rates of major or clinically relevant nonmajor bleeding comparing apixaban and warfarin in patients with AF and end-stage kidney disease on hemodialysis. Clinically relevant bleeding events were ≈10-fold more frequent than stroke or systemic embolism among this population on anticoagulation, highlighting the need for future randomized studies evaluating the risks versus benefits of anticoagulation among patients with AF and end-stage kidney disease on hemodialysis.Registration: URL: https://www.Clinicaltrials: gov; Unique identifier: NCT02942407. [ABSTRACT FROM AUTHOR]