Smoking is associated with a higher complication and failure rate in arteriovenous grafts for haemodialysis: A multi-centre experience.

INTRODUCTION: Arteriovenous grafts (AVG) for haemodialysis (HD) access are recommended as a second line modality due to higher morbidity and mortality rates than arteriovenous fistulae (AVF). Smoking is already established as a risk factor in lower extremity bypass graft failure used for peripheral vascular disease, but its effect on AVGs remains unclear. We aimed to investigate the relationship of smoking on AVG outcomes. METHODS: A 3 year (01/08/2015-01/08/2018) multi-centre retrospective study was carried out on patients receiving an AVG for HD. Data included patient demographics, medical history, operation, type of graft, postoperative course and primary and secondary patency rates. Statistical analyses performed were Kaplan-Meier curves and Cox's proportional hazard regression. RESULTS: Fifty-five AVGs were performed (1052 AVF performed) in this period. The most common complication was thrombosis (38.9%). Primary patency at 6, 12 and 24 months were 55%, 45% and 44% respectively. Secondary patency at 6, 12 and 24 months were 63%, 56% and 54% respectively. Smoking was found to be a poor prognostic factor for primary (HR 3.734 (1.818-7.668 95% CI) p < 0.001) and secondary patency (HR 6.238 (2.729-14.257) p < 0.001). Smoking was also significantly associated with graft thrombosis (HR 5.741 (2.380-13.848 95% CI) p < 0.001). DISCUSSION: Primary patency rates are lower than previous reports whilst secondary patency is equivalent. Smoking results in a greater risk of thrombosis and poorer primary and secondary patency. This is recognised in vascular surgical grafts, but has not been previously described in AVGs for HD access. Smoking is a modifiable risk factor and as AVGs are typically used for end-stage vascular access patients. Pre-operative strategies to promote smoking cessation, including patient education and prehabilitation should be employed to improve outcomes.

Increasing Uptake of COVID-19 Vaccination and Reducing Health Inequalities in Patients on Renal Replacement Therapy-Experience from a Single Tertiary Centre.

BACKGROUND: COVID-19 vaccination has changed the landscape of the COVID-19 pandemic; however, decreased uptake due to vaccine hesitancy has been observed, particularly in patients from minority ethnic backgrounds and socially deprived areas. These patient characteristics are common in patients on Renal Replacement Therapy (RRT), a population at extremely high risk of developing serious illness from COVID-19 and who would thus benefit the most from the vaccination programme. We designed a bespoke COVID-19 vaccination programme for our RRT population with the aim of decreasing health inequalities and increasing vaccination uptake. METHODS: Key interventions included addressing vaccine hesitancy by deploying the respective clinical teams as trusted messengers, prompt eligible patient identification and notification, the deployment of resources to optimise vaccine administration in a manner convenient to patients, and the timely collection and analysis of local safety and efficacy data. First, COVID-19 vaccination data in relation to ethnicity and social deprivation in our RRT population, measured by the multiple deprivation index, were analysed and compared to uptake data in the total regional adult clinically extremely vulnerable (CEV) population in Greater Manchester (GM). Univariate logistic regression analysis was used to explore the factors associated with not receiving a vaccine. RESULTS: Out of 1156 RRT patients included in this analysis, 96.7% received the first dose of the vaccination compared to 93% in the cohort of CEV patients in the GM. Age, gender, ethnicity, and a lower index of multiple deprivation were not identified as significant risk factors for poor first dose vaccine uptake in our cohort. Vaccine uptake in Asian and Black RRT patients was 94.9% and 92.3%, respectively, compared to 93% and 76.2% for the same ethnic groups in the reference CEV GM. Vaccine uptake was 96.1% for RRT patients in the lowest quartile of the multiple deprivation index, compared to 90.5% in the GM reference population. CONCLUSION: Bespoke COVID-19 vaccination programmes based on local clinical teams as trusted messengers can improve negative attitudes towards vaccination and reduce health inequalities.

Humoral Response in Hemodialysis Patients Following COVID-19 Vaccination and Breakthrough Infections during Delta and Omicron Variant Predominance.

BACKGROUND: The advancement of COVID-19 vaccination programs globally has been viewed as an integral strategy to reduce both the number of COVID-19 cases and consequential complications of COVID-19, particularly for high-risk patient groups. There are limited data on the antibody response and protection from disease infection and severity in patients requiring hemodialysis (HD) following COVID-19 vaccination during the Delta and Omicron variant predominance. We conducted a study aiming to evaluate humoral immunity derived from two different COVID-19 vaccines administered to our in-centre HD population and investigated the characteristics of breakthrough COVID-19 infections occurring post-vaccination within this population. METHODS: This is a prospective observational study including patients receiving HD at Salford Royal Hospital. The first and second doses of COVID-19 vaccinations (Pfizer BioNTech BNT162b2 or Oxford AstraZeneca ChAdOx1 nCoV-19) were administered to this patient cohort since January 2021. The incidence of any breakthrough COVID-19 infections occurring in double vaccinated patients between 1 April 2021 and 15 January 2022 was recorded. Patients were screened weekly with nasal and pharyngeal nasopharyngeal swabs for real-time Reverse Transcription Polymerase Chain Reaction (rRT-PCR) for COVID-19, whilst SARS-CoV-2 antibody testing was performed alongside monthly routine HD bloods. RESULTS: Four hundred eleven patients receiving HD were included in this study, of which 170 of 178 patients (95.5%) with available data on antibody status following two doses of the Pfizer BioNTech BNT162b2 vaccination had detectable antibody response, whilst this was the case for 97 of 101 patients (96.1%) who received two doses of the Oxford AstraZeneca ChAdOx1 nCoV-19 vaccine. For 12 seronegative patients who received a booster vaccine (third dose), nine seroconverted, while one remained negative and two were not tested. No statistically significant differences were observed with regards to antibody status between those receiving Pfizer BioNTech BNT162b2 and Oxford AstraZeneca ChAdOx1 nCoV-19 vaccines. Sixty-three of 353 patients with two doses of COVID-19 vaccination had breakthrough COVID-19 infection (40 during Delta and 23 during Omicron variant predominance). Of the 40 patients during the delta period, five were admitted into hospital and there were two reported deaths due to COVID-19-related illness. There were no COVID-19 associated hospitalizations or deaths during the Omicron variant predominance. CONCLUSIONS: The vast majority of HD patients who received two doses of the Pfizer BioNTech BNT162b2 or Oxford AstraZeneca ChAdOx1 nCoV-19 vaccinations developed detectable antibody responses. Our results support the value of booster vaccination with mRNA-based COVID-19 vaccine in HD patients and highlight the need for ongoing surveillance programmes with rRT-PCR and antibody testing for timely detection of positive cases.

A Quality Improvement Project to Minimize COVID-19 Infections in Patients Receiving Haemodialysis and the Role of Routine Surveillance Using Nose and Throat Swabs for SARS-CoV-2 rRT-PCR and Serum Antibody Testing.

BACKGROUND: Patients receiving in-centre haemodialysis (ICHD) are highly vulnerable to COVID-19. OBJECTIVE: We created a quality improvement (QI) project aimed to eliminate outbreaks of COVID-19 in haemodialysis units and evaluated the utility of surveillance rRT-PCR test and SARS-CoV-2 serum antibodies for prompt identification of patients infected with COVID-19. METHODS: A multifaceted QI programme including a bundle of infection prevention control (IPC) measures was implemented across 5 ICHD units following the first wave of the pandemic in June 2020. Primary outcomes evaluated before and after QI implementation were incidence of outbreaks and severe COVID-19 illness defined as COVID-19-related death or hospitalization. Secondary outcomes included the proportion of patients identified in the pre-symptomatic/asymptomatic phase on surveillance rRT-PCR screening and the incidence and longevity of SARS-CoV-2 antibody response. RESULTS: Following the implementation of the QI project, there were no further outbreaks. Pre- and post-implementation comparison showed a significant reduction in COVID-19-related mortality and hospitalization (26 vs. 13 events, respectively, p < 0.001). Surveillance rRT-PCR screening identified 39 asymptomatic or pre-symptomatic cases out of a total of 59 rRT-PCR-positive patients (39/59, 66%). SARS-CoV-2 antibody levels were detected in 72/74 (97%) rRT-PCR-positive patients. Amongst rRT-PCR-positive patients diagnosed before August 2020, 96% had detectable antibodies until January 2021 (days from the rRT-PCR test to last antibody testing, 245-280). CONCLUSIONS: Systematic implementation of a bundle of IPC measures using QI methodology and surveillance rRT-PCR eliminated outbreaks in HD facilities. Most HD patients mount and sustain antibody response to COVID-19 for over 8 months.

Safely reducing haemodialysis frequency during the COVID-19 pandemic.

BACKGROUND: Patients undergoing haemodialysis (HD) are at higher risk of developing worse outcomes if they contract COVID-19. In our renal service we reduced HD frequency from thrice to twice-weekly in selected patients with the primary aim of reducing COVID 19 exposure and transmission between HD patients. METHODS: Dialysis unit nephrologists identified 166 suitable patients (38.4% of our HD population) to temporarily convert to twice-weekly haemodialysis immediately prior to the peak of the COVID-19 pandemic in our area. Changes in pre-dialysis weight, systolic blood pressure (SBP) and biochemistry were recorded weekly throughout the 4-week project. Hyperkalaemic patients (serum potassium > 6.0 mmol/L) were treated with a potassium binder, sodium bicarbonate and received responsive dietary advice. RESULTS: There were 12 deaths (5 due to COVID-19) in the HD population, 6 of which were in the twice weekly HD group; no deaths were definitively associated with change of dialysis protocol. A further 19 patients were either hospitalised and/or developed COVID-19 and thus transferred back to thrice weekly dialysis as per protocol. 113 (68.1%) were still receiving twice-weekly HD by the end of the 4-week project. Indications for transfer back to thrice weekly were; fluid overload (19), persistent hyperkalaemia (4), patient request (4) and compliance (1). There were statistically significant increases in SBP and pre-dialysis potassium during the project. CONCLUSIONS: Short term conversion of a large but selected HD population to twice-weekly dialysis sessions was possible and safe. This approach could help mitigate COVID-19 transmission amongst dialysis patients in centres with similar organisational pressures.