Keeping the vascular access alive during the COVID-19 pandemic

Background: Delay in care of suspected stenosis or thrombosis can increase the chance of losing hemodialysis access. Many procedures were canceled or postponed at the start of the COVID-19 pandemic. We have done a study to determine if the COVID-19 pandemic affected dialysis access care. Methods: We performed a retrospective chart review to evaluate the incidence of both fistula and graft thrombectomies between April 1, 2020, and March 31, 2021, designated as the COVID-19 group and compared it with an incidence between April 1, 2019, and March 31, 2020, designated as the pre-COVID-19 group. Unsuccessful thrombectomy was defined as subsequent tunneled hemodialysis catheter placement within 48 hours after thrombectomy due to clotted access. Results: There was no significant difference in the total fistula and graft thrombectomies between the two time periods: 44 cases in the pre-COVID-19 era, the incidence rate of 0.12 per patient-year;54 cases in the COVID-19 era, the incidence rate of 0.14 per patient-year (HR=1.23, 95% CI= 0.81-1.89, p=0.31). However, there was a significant increase in the fistula thrombectomy in the COVID-19 era: 9 cases in the pre-COVID-19 era, the incidence rate of 0.024 per patient-year;21 cases in the COVID-19 era, the incidence rate of 0.057 per patient-year (HR=2.38, 95% CI= 1.03-5.88, p=0.02). In addition, the incidence of unsuccessful fistula thrombectomy also increased significantly: 2 cases in the pre-COVID-19 era, the incidence rate of 0.005 per patient-year;9 cases in the COVID-19 era, the incidence rate of 0.024 per patient-year (HR=4.54, 95% CI= 1.01-50, p=0.03). There was no significant difference in total as well as unsuccessful graft thrombectomy between the two eras. Conclusions: We noticed a significant increase in fistula thrombosis and unsuccessful fistula thrombectomy in 1-year of the COVID-19 pandemic. This could be due to a delay in referring the patients for treatment of fistula stenosis. Even though the dialysis access procedures were considered essential, there might have been hesitancy on part of patients and referring dialysis center which led to this result. However, we did not notice this trend in AV graft. Timely referral for intervention is important to prevent vascular access thrombosis and loss.

Phenotype and outcomes of AKI associated with COVID-19 in urban New Orleans

Background: Acute kidney injury (AKI) is a manifestation of COVID-19 (CoVAKI). However, there is paucity of data from United States, particularly in a predominantly African American (AA) population. We report the phenotype and outcomes of AKI at an academic hospital in New Orleans. Methods: We conducted an observational study in patients hospitalized at Ochsner Medical Center over 1-month period with COVID-19 and diagnosis of AKI by KDIGO. We examined the rates of renal replacement therapy (RRT) and in-hospital mortality as outcome measures. Adjudication of cause of AKI was independently performed via manual chart review by 3 study team members. Results: Of 644 admissions with COVID-19, 69 were excluded due to ESRD or kidney transplant. Thus, 575 patients entered the cohort [173 (28%) to an intensive care unit (ICU)]. Patients were predominantly AA (71%). AKI was diagnosed in 161 patients (28% overall, 61% of ICU admissions), median age 65 (34 - 96), predominantly male (62%) and hypertensive (83%). Median follow up was 25 (1 - 45) days. Vasopressors and/or mechanical ventilation was required in 105 (65%) of them. In-hospital mortality rate for those with AKI was 50% (80/181). De novo AKI was diagnosed in 65%, whereas AKI over preexisting chronic kidney disease occurred in 35% of the cohort. Ninetyone (57%) patients arrived with AKI, whereas the remaining 43% acquired AKI during the hospitalization [median hospital day of AKI onset: 4 (2 - 10)]. RRT was required in 89/161 (55%) and 77/105 (73%) patients for all AKI cases and the ICU subset, respectively. The mortality rate for those with AKI-RRT was 72% (64/89). Hemodynamic instability leading to ischemic acute tubular injury (ATI) and rhabdomyolysis accounted for 66% and 7% of the etiology, respectively. Reversible prerenal azotemia occurred in 9%. In 13%, no obvious cause of AKI was identified aside from the COVID-19 diagnosis. Three (1.8%) patients had De novo collapsing glomerulopathy. Conclusions: CoV-AKI is associated with high rates of RRT, ICU care and death. Hemodynamic instability leading to ischemic ATI is the predominant cause of AKI in this setting, but other etiologies contribute to the overall AKI burden.

Urinary sediment microscopy in COVID-19-associated AKI

Background: Acute kidney injury (AKI) is a complication of COVID-19 that is not fully understood. Microscopic examination of the urinary sediment (MicrExUrSed) is a valuable diagnostic tool in AKI. Thus far, there has been scarcity of data about MicrExUrSed in COVID-19-associated AKI (CoV-AKI). We hypothesized that MicrExUrSed provides diagnostic clues in CoV-AKI. Methods: We conducted a prospective observational study in patients seen for inpatient nephrology consultation with KDIGO AKI stage ≥ 1 and COVID-19 over a 1-month period. Urine specimens were collected with personal protective equipment to perform MicrExUrSed. Slides were assessed for presence of white blood cells (WBC) [≥ 2+ dipstick, ≥ 6 per low power field (LPF)], red blood cells (RBC) (≥ 2+ dipstick, ≥ 8 per LPF), acanthocytes, granular casts (GC), renal tubular epithelial cell casts (RTECC) and waxy casts (WxC). Slides were assigned to a category of acute tubular injury (ATI) based on either a Perazella cast score ≥ 2 or a Chawla cast score ≥ 3. Results: Among 161 cases of AKI, MicrExUrSed was performed in 20 (12.4%). Anuria and contact precautions were barriers to obtain specimens. GC were found in 17 (85%) of which 16 (80%) had 'muddy' brown GC (MBGC). A median 5 MBGC per LPF (1-20) were found in a median 40% (10-95%) of LPFs. WxC were found in 10 (50%) cases with a median 2 (1-5) per LPF, all of whom had MBGC also present. RTECC were found in 3 (15%) cases with a median 1 (1-4) per LPF. Altogether, ATI score was assigned to 17 (85%) patients, of which 12 (60%) had AKI either after a hemodynamic/ischemic insult (9) or after a toxic insult (3) (rhabdomyolysis, vancomycin, contrast) and 3 (15%) had biopsy-proven ATI along with collapsing glomerulopathy;for a total of 15 (75%) patients with either clinical or histological evidence on ATI matching the MicrExUrSed findings. Ten (50%) and 5 (25%) had WBCs and RBCs, respectively. Acanthocytes were found in 1 (5%) patient with presumptive proliferative endocapillary glomerulonephritis. Conclusions: MicrExUrSed in most patients with CoV-AKI showed overt evidence of ATI with an abundance of MBGC and WxC, including in cases of coexisting glomerulopathy. Pyuria was observed in half. The diagnostic utility of MicrExUrSed in CoV-AKI was comparable to that demonstrated in other forms of AKI.