Risks and outcomes of critical limb ischemia in hemodialysis patients: a prospective cohort study.

Background: Peripheral arterial disease (PAD) is more common in patients receiving maintenance hemodialysis than in the general population. Critical limb ischemia (CLI), the most severe form of PAD, is associated with high amputation and mortality risk. However, few prospective studies are available evaluating this disease's presentation, risk factors and outcomes for patients receiving hemodialysis. Methods: The Hsinchu VA study, a prospective multicentre study, investigated the impact of clinical factors on cardiovascular outcomes of patients receiving maintenance hemodialysis from January 2008 until December 2021. We evaluated the presentations and outcomes of patients with newly diagnosed PAD and the correlations of clinical variables with newly diagnosed CLI. Results: Of 1136 study participants, 1038 had no PAD on enrolment. After a median follow-up period of 3.3 years, 128 had newly diagnosed PAD. Of these, 65 presented with CLI, and 25 underwent amputation or died from PAD. Patients presenting with CLI had more below-the-knee (52%) and multi-level (41%) disease, and completely occluded segments (41%), and higher risk for amputation or PAD-related death compared with patients without CLI (27.7% vs 9.5%, P = .01). After multivariate adjustment, disability, diabetes mellitus, current smoking and atrial fibrillation were significantly associated with newly diagnosed CLI. Conclusions: Patients undergoing hemodialysis had higher rates of newly diagnosed CLI than the general population. Those with disabilities, diabetes mellitus, smoking and atrial fibrillation may require careful examination for PAD. Trial registration: Hsinchu VA study, ClinicalTrials.gov identifier: NCT04692636.

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.

Stent grafts improved patency of ruptured hemodialysis vascular accesses.

This study aimed to compare stent graft with balloon tamponade for ruptured dialysis access during percutaneous transluminal angioplasty. Patients over an 8-year period (2010-2018) were identified from a database of 11,609 procedures. The primary endpoint was target lesion primary patency at 12 months. A total of 143 patients who had rupture dialysis access were enrolled, of whom 52 were salvaged by stent grafts and 91 were salvaged by balloon tamponade. The 6-month target lesion primary patency was greater in the stent graft group than in the balloon tamponade group (66.7% vs. 29.5%, P < 0.001). The benefit of stent grafts was sustained for 12 months (52.5% vs. 9.0%, P < 0.001). The stent grafts increased the median time from the index procedure to the next intervention in the ruptured area by 171 days (260 vs. 89 days) at 12 months. There was no significant difference in the access circuit patency rates at 6 months (25.5% vs. 19.8%, P = 0.203) and 12 months (12.0% vs. 5.8%, P = 0.052). The patency results of the stent grafts remained after the multivariable adjustment analysis. Compared to balloon tamponade alone, stent grafts provided superior target lesion primary patency at 6 and 12 months. The access circuit patency rates were similar.

The Impact of Frailty on the Outcomes of Hemodialysis Vascular Access.

BACKGROUND: Frailty has been associated with mortality and adverse cardiovascular outcomes in patients with hemodialysis (HD), however the relevance of frailty on the outcomes of HD vascular access remains unclear. METHODS: We enrolled a cohort of patients with prevalent HD between August 2018 and November 2018. The presence of 5 frailty phenotypes was determined at enrollment, using the modified Fried's criteria. Data regarding vascular access events or mortality were linked to prospectively collected data up to 24 months after enrollment. RESULTS: Of the 382 patients screened, 313 were recruited in the final analysis. The participants' mean age was 66 years, and 42.5% were female. Among all participants, 40.3% were determined to be frail and 29.4% pre-frail. The frail phenotype was associated with age, female gender, lower body mass index, unemployment, lower education level, and higher dialysis clearance. During the follow-up period (median, 24 months), 112 patients had vascular access events (non-frail, 27.4%; pre-frail, 35.9%; frail, 46.1%; p = 0.003) and 45 patients experienced thrombosis of the vascular access (non-frail, 4.2%; pre-frail, 9.8%; frail, 18.3%; p = 0.002). Cox regression analysis showed that frail patients had a 2.2-fold higher risk of experiencing vascular access events than non-frail patients [hazard ratio (HR): 2.205, 95% confidence interval (CI): 1.377-3.532, p = 0.001], but the association was not significant (HR: 1.634, 95% CI: 0.938-2.848, p = 0.082) after multivariate adjustment. CONCLUSIONS: The frail phenotype is common in Taiwanese patients who undergo maintenance HD and is associated with adverse outcomes of dialysis vascular access.

Use of the Viabahn covered stent for the treatment of venous rupture during interventions of dysfunctional or thrombosed hemodialysis vascular access.

BACKGROUND: Angioplasty-related vessel rupture is a common complication of interventions. The effect of covered stents to treat venous rupture has been evaluated in smaller series, but should be further evaluated. OBJECTIVE: To report the immediate outcomes and patency rates of a covered stent to rescue angioplasty-related venous rupture of hemodialysis vascular access. METHODS: From January 2013 to December 2018, 113 procedures complicated with vessel ruptures were retrospectively analyzed from a prospectively collected database of 8146 hemodialysis access interventions. The strategies to salvage vessel ruptures were based on the discretion of the treating physicians. Follow-up outcomes were obtained via review of the angiographic images, procedural notes, and medical and dialysis records within 12 months after the index procedures. RESULTS: A total of 52 vessel ruptures (21 fistulas, 31 grafts) salvaged by using Viabahn covered stents were enrolled. Vessel ruptures developed in 28 (53.8%) thrombectomy procedures. Device success was achieved in all procedures (100%) and clinical success was achieved in 50 (96.2%). The primary patency of the stent area was 66.0% at 6 months and 50.0% at 12 months. The primary patency of the entire access circuit was 27.4% at 6 months and 16.0% at 12 months. The most common cause of access circuit primary patency loss was thrombotic occlusion for graft accesses and restenosis at stent area for native accesses. Eleven vascular accesses were abandoned within 12 months after vessel ruptures, and the secondary patency rate of the entire access circuit was 78.0% at 12 months. CONCLUSIONS: Treatment of angioplasty-induced vessel rupture of hemodialysis vascular accesses by using Viabahn covered stents has good immediate outcomes and patency results at the stent area. Nonetheless, the patency rate of entire access circuit was still below the threshold recommended by guidelines.

A randomized feasibility study of the effect of ascorbic acid on post-angioplasty restenosis of hemodialysis vascular access (NCT03524846).

Restenosis remains a significant problem after angioplasty of hemodialysis vascular access. Both experimental and clinical studies have shown a protective effect of antioxidants against post-angioplasty restenosis. A prospective, randomized, feasibility study was conducted to investigate the effect of ascorbic acid to prevent restenosis. Ninety-three hemodialysis patients were randomized into three groups after angioplasty: placebo (n = 31), 300 mg ascorbic acid (n = 31), and 600 mg ascorbic acid (n = 31), treated intravenously 3 times per week for 3 months. Eighty-nine completed the clinical follow-up, and 81 had angiographic follow-up. In the angiographic follow-up, the mean (stand deviation) late loss of luminal diameter for the placebo, 300 mg, and 600 mg groups were 3.15 (1.68) mm, 2.52 (1.70) mm (P = 0.39 vs. placebo group), and 1.59 (1.67) mm (P = 0.006, vs. placebo group), with corresponding angiographic binary restenosis of 79%, 67% (P = 0.38 vs. placebo group), and 54% (P = 0.08 vs. placebo group). The post-interventional primary patency rates at 3 months were 47%, 55% (P = 0.59 vs. placebo group), and 70% (P = 0.18 vs. placebo group) for placebo, 300 mg, and 600 mg groups. Our results demonstrated that intravenous 600 mg ascorbic acid was a feasible therapy and might attenuate restenosis after angioplasty; however, its effect on post-interventional primary patency was modest.

Investigation of the pathophysiology of cardiopulmonary bypass using rodent extracorporeal life support model.

BACKGROUND: Extracorporeal life support (ECLS) systems are life-saving devices used for treating patients with severe cardiopulmonary failure. In this study, we implemented a rat model of ECLS without the administration of inotropes or vasopressors. METHODS: The rats underwent 5 min of untreated asphyxial cardiac arrest and were resuscitated by ECLS for 30 min. The right external jugular vein and right femoral artery were separately cannulated to the ECLS outflow and inflow, respectively. Thereafter, ECLS was terminated, wounds were closed, and mechanical ventilation was provided for another 90 min. Subsequently, blood gas and hemodynamic analyses were performed. The plasma levels of C-reactive protein (CRP), interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α) were measured 120 min after reperfusion. RESULTS: The metabolic rate of lactate in the group of asphyxial cardiac arrest rescued by ECLS was slow; therefore, the pH at 120 min after reperfusion was significantly lower in this group than that in the group of normal rats treated with ECLS. The hemodynamic data showed no between-group differences. The plasma levels of CRP, IL-6, IL-10, and TNF-α increased after ECLS treatment. CONCLUSIONS: We successfully established a rodent ECLS model, which might be a useful approach for studying the pathophysiology induced by ECLS under clinical conditions.

Dimerized plasmin fragment D as a potential biomarker to predict successful catheter-directed thrombolysis therapy in acute deep vein thrombosis.

OBJECTIVES: The value of dimerized plasmin fragment D in the clinical monitoring during the catheter-directed thrombolysis in patients with acute deep vein thrombosis is not known. METHODS: Dimerized plasmin fragment D levels in 24 patients with acute deep vein thrombosis undergoing catheter-directed thrombolysis were prospectively evaluated. The plasma dimerized plasmin fragment D level was measured serially before and at every 12 h during catheter-directed thrombolysis for 24 h. Technical success was defined as restoration of patency and flow with less than 50% residual thrombus by surveillance rotational venography. RESULTS: Technical success was achieved in 79.2% (19 of 24) of the treated limbs after catheter-directed thrombolysis. In univariate analysis, there was significant elevation of the dimerized plasmin fragment D at 12th h after starting the catheter-directed thrombolysis (P < 0.05) in patients with less than 50% residual thrombus stenosis. The optimal cut-off value of dimerized plasmin fragment D to predict successful catheter-directed thrombolysis was determined as 18.4 µg/ml at the 12th h after starting the catheter-directed thrombolysis with sensitivity 0.8 and specificity 0.8 (P = 0.03). It was further validated in multivariate logistic regression analysis (odds ratio: 14.38; 95% CI: 1.22-169.20; P = 0.03). CONCLUSIONS: Catheter-directed thrombolysis is safe and effective for restoration of blood flow in patients with acute deep vein thrombosis. Dimerized plasmin fragment D value greater than 18.4 µg/ml at the 12th h after starting catheter-directed thrombolysis had a high predictive rate of greater than 50% lysis at the end of catheter-directed thrombolysis.

Transapical endovascular repair with a table-tailored endograft to treat ascending aortic dissection.

Current endografts, which were designed primarily for the descending aorta, have significant limitations when used in the ascending aorta. We report our initial experience using the transapical endovascular approach to treat an ascending aortic dissection with a table-tailored commercial stent graft.