Temporal distribution and biological determinants of thrombotic events after interventions for dialysis vascular access

A randomized controlled trial evaluated the efficacy and safety of apixaban for prevention of recurrent thrombosis after thrombectomy of hemodialysis vascular access

Dialysis vascular access thrombosis poses a substantial challenge for individuals undergoing hemodialysis. The efficacy and safety of apixaban, a direct oral coagulation factor Xa inhibitor, in preventing recurrent access thrombosis have yet to be explored. Here, a multicenter randomized control study (NCT04489849) enrolled hemodialysis patients to evaluate this who underwent successful endovascular thrombectomy within 48 hours. Participants were assigned to standard care or standard care plus apixaban, 2.5 mg twice daily for three months. The trial design involved open-label administration, with independent adjudication of endpoints. The primary efficacy endpoint was recurrent access thrombosis within three months after thrombectomy. A total of 186 patients with well-balanced baseline characteristics were enrolled, 93 randomized to the apixaban group and 93 to the control group. The apixaban group demonstrated a significantly lower rate of access thrombosis at three months than the control group (24.0% vs. 40.8%; hazard ratio, 0.52 [95% confidence interval 0.31-0.88]), along with a significantly better primary patency failure rate (32.2% vs. 49.5%, 0.57 [0.36-0.91]). Safety outcomes showed comparable death rates and major bleeding incidents but significantly higher incidence of minor bleeding in the apixaban group (22.6% vs. 7.5%). The effect of apixaban did not show interaction in subgroups of different access types, antiplatelet usage, severity of comorbidities, or history of thrombosis. Thus, apixaban effectively reduced the risk of recurrent thrombosis in hemodialysis vascular access post-thrombectomy. Despite a minor increase in bleeding adverse effects, the net clinical benefit favors the use of apixaban in this context.

Risk factors for thrombosis in dialysis patients: A comprehensive systematic review and meta-analysis

AIM

To identify the factors associated with thrombosis in dialysis patients.

BACKGROUND

Thrombosis is a leading cause of vascular access failure in dialysis patients. Numerous risk factors contribute to thrombosis in this population.

METHODS

A systematic search was conducted across international databases using standardized keywords. The quality of the selected studies was assessed using the STROBE and CONSORT checklists. The findings were summarized in a Garrard table. Meta-analysis was performed using CMA software. The study adhered to the guidelines outlined in the PRISMA statement.

RESULTS

A total of 180 articles were reviewed. The odds ratio for thrombosis in patients with arteriovenous grafts compared to arteriovenous fistulas was 10.93 (95 % CI: 9.35-12.78), demonstrating statistical significance (P = 0.001). Similarly, hemodialysis patients had an odds ratio of thrombosis 3.60 times higher than non-hemodialysis patients (95 % CI: 3.54-4.19), with statistical significance (P = 0.001). Patients undergoing single-stage basilic vein transposition had a 1.89 times higher risk of thrombosis compared to those undergoing two-stage transposition (95 % CI: 1.04-3.46), also demonstrating statistical significance (P = 0.038).

CONCLUSIONS

Thrombosis in patients with end-stage renal disease undergoing dialysis was significantly associated with various factors, including graft access, single-stage basilic vein transposition, and hemodialysis. Additional contributing factors to thrombosis included diabetes, elevated homocysteine levels, female gender, age over 50, access location, and low access blood flow velocity. The analysis revealed a higher incidence of thrombosis in end-stage renal disease patients undergoing hemodialysis compared to those not undergoing dialysis, as well as in patients with arteriovenous grafts compared to those with arteriovenous fistulas. These findings underscore the importance of recognizing and managing these risk factors to prevent thrombotic events and enhance patient care within the dialysis setting.

Risk Factors for Thromboembolic Events in Patients With Dialysis-Dependent CKD: Pooled Analysis of Phase 3 Roxadustat Trials in Japan

INTRODUCTION

Thromboembolic events have occurred in clinical trials of roxadustat. This post hoc analysis explored potential factors related to thromboembolic events in dialysis-dependent patients treated with roxadustat in four phase 3 clinical trials in Japan.

METHODS

Thromboembolic events with onset before and after week 12 were evaluated. Baseline risk factors for thromboembolic events were investigated by Cox regression analyses. Nested case-control analyses using conditional logistic models with matched pairs of case-control data explored relationships between thromboembolic events and laboratory parameters.

RESULTS

Of the 444 patients, 56 thromboembolic events were observed in 44 patients during ≤ 52 weeks of treatment. The proportion of venous and arterial thromboembolic events gradually increased after week 12. Baseline risk factors included hemodialysis (vs peritoneal dialysis), advanced age (≥ 65 years), shorter dialysis vintage (< 4 months), and history of thromboembolism. The absence of concomitant intravenous or oral iron therapy (including ferric citrate) was associated with thromboembolic events before week 12 (hazard ratio 11.25; 95% confidence interval [CI] 3.36-37.71; vs presence). Case-control analysis revealed that low average transferrin saturation (< 10%; unadjusted odds ratio [OR] 6.25; 95% CI 1.52-25.62; vs ≥ 20%), high average transferrin level (≥ 2.5 g/L; unadjusted OR 4.36; 95% CI 1.23-15.39; vs < 2.0 g/L), and high average roxadustat dose (≥ 150 mg; unadjusted OR 5.95; 95% CI 1.07-33.16; vs < 50 mg) over the previous 8 weeks before the event onset were associated with thromboembolic events after week 12. However, adjustment for iron status extinguished the significant relationship between roxadustat dose and events. Multivariate case-control analysis showed that increased transferrin from baseline (≥ 1.0 g/L; adjusted OR 7.85; 95% CI 1.82-33.90; vs < 0.5 g/dL) and decreased mean corpuscular volume (< - 2 fL; adjusted OR 5.55; 95% CI 1.73-17.83; vs ≥ 0 fL) were associated with increased risk of thromboembolic events.

CONCLUSION

In addition to established risk factors, iron deficiency may be related to thromboembolic events. Graphical Abstract available for this article.

TRIAL REGISTRATION

NCT02780726, NCT02952092, NCT02780141, NCT02779764.

Risk Factors for Thromboembolic Events in Patients With Dialysis-Dependent CKD: Pooled Analysis of Four Global Roxadustat Phase 3 Trials

INTRODUCTION

Risk factors for thromboembolic events in patients with dialysis-dependent chronic kidney disease (CKD) receiving roxadustat are unknown. Iron deficiency has been reported as a risk factor for thrombosis in the general population.

METHODS

Thromboembolic events with onset before and after week 12 in patients receiving roxadustat were evaluated in this pooled analysis of four global phase 3 trials, PYRENEES, SIERRAS, HIMALAYAS, and ROCKIES. Baseline risk factors for thromboembolic events were investigated by Cox regression analyses. Nested case-control analyses with matched pairs of case-control data explored the relationship between thromboembolic events and last known laboratory parameters before event onset.

RESULTS

Of 2354 patients, 1026 thromboembolic events were observed in 568 patients. Baseline risk factors found included hemodialysis (vs peritoneal dialysis), advanced age (≥ 65 years), Black race, high high-sensitivity C-reactive protein, and history of thromboembolism, cardiovascular disease, or diabetes. Univariate case-control analyses revealed that high hemoglobin rate of rise (≥ 0.5 g/dL/week; odds ratio [OR] 2.09; 95% confidence interval [CI] 0.98-4.46) showed a trend towards increased risk of thromboembolic events before week 12, and high rate of hemoglobin decline was associated with events after week 12 (< - 0.5 g/dL/week; OR 3.73; 95% CI 1.68-8.27) as compared to stable hemoglobin levels (≥ - 0.1 to < 0.1 g/dL/week). Multivariate case-control analyses showed that low last known hemoglobin level (< 10 g/dL: adjusted OR 1.91; 95% CI 1.04-3.50; vs ≥ 12 g/dL) and low last known transferrin saturation (TSAT < 10%: adjusted OR 3.78; 95% CI 1.71-8.39; vs ≥ 30%) before event onset were associated with events after week 12. In patients with last known TSAT < 30%, higher roxadustat dose was associated with thromboembolic events; however, no association was observed in those with TSAT ≥ 30%.

CONCLUSIONS

Among various risk factors for thromboembolic events, it is reasonable to avoid a rapid increase and decline in hemoglobin levels as well as ensure TSAT ≥ 30%, rather than increasing the roxadustat dose. Graphical Abstract available for this article.

TRIAL REGISTRATION

NCT02278341, NCT02273726, NCT02052310, NCT02174731.

Association of Frailty With Thrombosis of Hemodialysis Vascular Access: A Prospective Taiwanese Cohort Study

RATIONALE & OBJECTIVE

Frailty, a multidimensional construct, has been associated with poor outcomes in patients receiving maintenance dialysis. This study assessed the association of frailty with dialysis vascular access patency.

STUDY DESIGN

Multicenter prospective cohort study.

SETTING & PARTICIPANTS

761 prevalent patients receiving hemodialysis at 9 centers in Taiwan as of January 2018.

EXPOSURE

Performance-based frailty was defined as 3 of the following: unintentional weight loss, weakness, exhaustion, low physical activity, and slow gait speed. Patients were categorized as prefrail if they had 1 or 2 of these characteristics.

OUTCOME

Rate of and time to dialysis access thrombosis. Data regarding vascular access events were collected for 30 months after enrollment through December 31, 2020.

ANALYTICAL APPROACH

Logistic regression analysis was used to estimate the association of clinical characteristics with frailty. Cox proportional hazards regression analysis was used to estimate the association of frailty with vascular access thrombosis adjusted for known clinical risk factors.

RESULTS

The patients' mean age was 66 years, 46% were female, 18% had synthetic graft accesses, and 82% arteriovenous fistulas. Overall, 31% were frail, 35% were prefrail, and 34% were not frail. The frailty phenotype was associated with age, female sex, low body mass index, diabetes mellitus, and prior stroke. During a median follow-up of 731 days, 161 patients (21%) had access thrombosis events (not frail, 14%; prefrail, 20%; frail, 30%; P < 0.001). Frail patients had a higher risk of vascular access thrombosis than nonfrail patients (HR, 2.31 [95% CI, 1.55-3.39], P < 0.001). After multivariable adjustment for age and comorbidities, frailty remained significantly associated with access thrombosis for both fistulas and grafts.

LIMITATIONS

Limited generalizability and potential residual confounding.

CONCLUSIONS

Frailty is associated with an increased risk of vascular access thrombosis. These findings highlight the risks of access failure experienced by frail patients receiving hemodialysis.

Oral Charcoal Adsorbents Attenuate Neointima Formation of Arteriovenous Fistulas

Chronic kidney disease (CKD) accelerates the development of neointima formation at the anastomosis site of arteriovenous (AV) fistulas. Accumulation of certain uremic toxins has a deleterious effect on the cardiovascular system. The oral charcoal adsorbent, AST-120, reduces circulating and tissue uremic toxins, but its effect on neointima formation at an AV fistula is unknown. To understand the effect of CKD and AST-120 on neointima formation, we created AV fistulas (common carotid artery to the external jugular vein in an end-to-side anastomosis) in mice with and without CKD. AST-120 was administered in chow before and after AV fistula creation. Administration of AST-120 significantly decreased serum indoxyl sulfate levels in CKD mice. CKD mice had a larger neointima area than non-CKD mice, and administration of AST-120 in CKD mice attenuated neointima formation. Both smooth muscle cell and fibrin components were increased in CKD mice, and AST-120 decreased both. RNA expression of MMP-2, MMP-9, TNFα, and TGFβ was increased in neointima tissue of CKD mice, and AST-120 administration neutralized the expression. Our results provided in vivo evidence to support the role of uremic toxin-binding therapy on the prevention of neointima formation. Peri-operative AST-120 administration deserves further investigation as a potential therapy to improve AV fistula patency.