Mu-Yang Hsieh

Serum Indoxyl Sulfate Associates with Postangioplasty Thrombosis of Dialysis Grafts

Hemodialysis vascular accesses are prone to recurrent stenosis and thrombosis after endovascular interventions.In vitro data suggest that indoxyl sulfate, a protein-bound uremic toxin, may induce vascular dysfunction and thrombosis. However, there is no clinical evidence regarding the role of indoxyl sulfate in hemodialysis vascular access. From January 2010 to June 2013, we prospectively enrolled patients undergoing angioplasty for dialysis access dysfunction. Patients were stratified into tertiles by baseline serum indoxyl sulfate levels. Study participants received clinical follow-up at 6-month intervals until June 2014. Primary end points were restenosis, thrombosis, and failure of vascular access. Median follow-up duration was 32 months. Of the 306 patients enrolled, 262 (86%) had symptomatic restenosis, 153 (50%) had access thrombosis, and 25 (8%) had access failure. In patients with graft access, free indoxyl sulfate tertiles showed a negative association with thrombosis-free patency (thrombosis-free patency rates of 54%, 38%, and 26% for low, middle, and high tertiles, respectively;P=0.001). Patients with graft thrombosis had higher free and total indoxyl sulfate levels. Using multivariate Cox regression analysis, graft thrombosis was independently predicted by absolute levels of free indoxyl sulfate (hazard ratio=1.14;P=0.01) and free indoxyl sulfate tertiles (high versus low, hazard ratio=2.41;P=0.001). Results of this study provide translational evidence that serum indoxyl sulfate is a novel risk factor for dialysis graft thrombosis after endovascular interventions.

Timely thrombectomy can improve patency of hemodialysis arteriovenous fistulas

Objective: The urgency with which salvage of thrombosed vascular accesses for dialysis should be attempted remains unknown. We examined the effect of a timely thrombectomy approach on vascular access outcomes for dialysis. Methods: A before‐and‐after study was conducted with patients on hemodialysis who had undergone endovascular thrombectomy. A timely thrombectomy initiative (ie, salvage within 24 hours of thrombosis diagnosis) was started in July 2015 at our institution. Data about thrombectomy procedures, performed within 1 year before and after the initiative was introduced, were abstracted from an electronic database. Immediate outcomes and patency outcomes were compared between the preinitiative (control) and postinitiative (intervention) groups. Results: During the study period, 329 patients were enrolled, including 165 cases before and 164 cases after the initiative. The intervention group had more thrombectomy procedures performed within 24 hours (93% vs 55%; P < .01) and within 48 hours (97% vs 79%; P < .01) than the control group. No between‐group differences in procedural success or clinical success rates were found. At 3 months, the intervention group had a higher postintervention primary patency rate than the control group, although this did not reach statistical significance (58% vs 48%; P = .06). After stratification into native or graft accesses, the patency benefit was observed in the native access group (68% vs 50%; P = .03) but not in the graft access group (50% vs 46%; P = .65). After adjusting for potential confounders, timely thrombectomy remained an independent predictor of postintervention primary patency (hazard ratio, 0.449; 95% confidence interval, 0.224–0.900; P = .02) for native dialysis accesses. Conclusions: Our results suggest that a timely thrombectomy approach, in which salvage is attempted within 24 hours of thrombosis diagnosis, improves postintervention primary patency of native but not graft accesses for dialysis.

Circulating Progenitor Cells Affect Thrombosis of Dialysis Arteriovenous Fistulas

Background: Arteriovenous fistula (AVF) thrombosis is a relevant cause of morbidity in hemodialysis (HD) patients. The number of circulating endothelial progenitor cells (EPCs) has been identified as a surrogate marker for vascular repair and health. Deficiency of EPCs has been demonstrated in dialysis patients to be associated with vascular events. Nonetheless, their role in thrombosis of AVFs remains unknown. Methods: From January 2010 to May 2013, 147 HD patients with dysfunctional AVFs were enrolled. Surface makers including CD34, KDR and CD133 were used in combination to determine the number of circulating EPCs. All participants were prospectively followed at 6-month interval until December 2015. The primary outcome was thrombosis of dialysis AVFs. Results: The median follow-up was 47 months, within which 42 patients experienced at least one episode of AVF thrombosis. Patients with AVF thrombosis had lower CD34+KDR+ cell counts compared with patients without thrombosis (median 5 vs. 13 per 150,000 mononuclear cells, p < 0.001). Kaplan-Meier analysis demonstrated an inverse relationship between CD34+KDR+ cell count tertiles and thrombosis-free patency (59, 69 and 86% for low, middle and high tertiles; p = 0.02). Using Cox regression analysis, AVF thrombosis was predicted by baseline CD34+KDR+ cell counts (hazards ratio (HR) 0.963, 95% CI 0.928-1.000, p = 0.05) and tertiles (high vs. low, HR 3.266, 95% CI 1.380-7.728, p < 0.01). In multivariate analysis, only CD34+KDR+ cell tertiles, C-reactive protein and lesion length remained independent predictors for thrombosis. Conclusion: Our study demonstrated an independently reverse association between circulating EPCs and thrombosis of dialysis AVFs. Further studies are warranted to ascertain whether EPCs serve as a marker or a therapeutic target for AVF thrombosis.

Impact on Pulmonary Arterial Pressures after Repeated Endovascular Thrombectomy of Dialysis Grafts: A Prospective Follow-up Study

PURPOSE Vascular access thrombosis is a common complication of arteriovenous dialysis grafts that results in silent pulmonary embolism (PE) in a substantial proportion of patients. However, the impact of repeated PE on the pulmonary vasculature remains unclear. MATERIALS AND METHODS From January 2010 to April 2012, 110 patients undergoing maintenance hemodialysis via arteriovenous grafts were recruited. Hemodynamic assessments, including transthoracic echocardiography and right heart catheterization, were performed at baseline and after 1 year to evaluate the changes in pulmonary artery (PA) pressures and heart function. RESULTS Fifty-two patients completed the follow-up hemodynamic assessment at a median duration of 535 days and had at least one endovascular thrombectomy procedure (median of seven). There was no significant difference in mean PA pressures between baseline and the end of follow-up (23.1 mm Hg ± 6.8 vs 21.6 mm Hg ± 6.1; P = .16). The change in mean PA pressure did not correlate with the number of thrombectomy procedures in the overall cohort (r = -0.02, P = .89) or in the subgroup with cardiopulmonary disease (r = -0.30, P = .14). The changes of mean PA pressure were not associated with number of thrombectomy procedures (β = -0.03, P = .89). CONCLUSIONS Repeated endovascular thrombectomy procedures are not related to changes in PA pressure in the short term. The present results support the safety of endovascular thrombectomy in the pulmonary vasculature.

Deficiency of circulating progenitor cells associated with vascular thrombosis of hemodialysis patients

Background. Hemodialysis (HD) patients have an increased risk of thrombosis. Endothelial progenitor cells (EPCs), which function in vascular repair, are deficient in HD patients. Nonetheless, the relationship between EPC deficiency and thrombosis in HD patients is unknown. Methods. From January 2010 to December 2012, circulating levels of EPCs that were positive for CD34 and kinase insert domain receptor (KDR) were measured in 269 HD patients. Patients received prospective follow‐ups at 6‐month intervals until May 2015. The primary outcome was the composite of HD access thrombosis and systemic vascular thrombosis. Results. There were 141 thrombotic events, 50 systemic vascular thrombotic events and 116 HD access thrombotic events. We found significantly negative associations between CD34+ KDR+ tertile and overall thrombotic events (low: 61%; middle: 56%; high: 40%; P = 0.02), systemic vascular thrombotic events (low: 27%; middle: 18%; high: 10%; P = 0.03) and HD access thrombotic events (low: 52%; middle: 46%; high: 36%; P = 0.02). Univariate analysis indicated that systemic vascular thrombotic events were positively associated with age, diabetes, dyslipidemia, vascular disease history, urea clearance, albumin and C‐reactive protein (CRP), and negatively associated with CD34+ KDR+ cell count. HD access thrombosis was positively associated with vascular disease history and CRP, and negatively associated with CD34+ KDR+ cell count. Multivariate analysis indicated that a low CD34+ KDR+ cell count was an independent risk factor for both types of thrombosis. Conclusions. Our study of a population of HD patients showed that a low level of circulating EPCs is associated with thrombosis.

Catheter‐directed therapy for acute renal vein thrombosis in systemic lupus erythematosus: A case report

We report our experience using catheter‐directed thrombectomy/thrombolysis (CDT) to treat a patient with acute renal vein thrombosis (RVT) associated with systemic lupus erythematosus (SLE). A 34‐year‐old woman presented with persistent left flank pain, and a renal ultrasonography examination revealed an enlarged left kidney. Contrast‐enhanced computed tomography confirmed the presence of acute left RVT. Because medical treatment failed to relieve her pain and the renal function was deteriorating, we attempted to salvage the occluded left renal vein using an endovascular approach. The pain was completely relieved after a CDT and an overnight urokinase infusion. A follow‐up computed tomography examination revealed the complete resolution of the thrombus. The creatinine level returned to normal (1.7–0.4 mg/dL), along with contrast enhancement in the left kidney, and this suggested the preservation of renal function. To our knowledge, this is the first report utilizing CDT to treat SLE‐associated RVT. When the renal function is deteriorating, CDT is worth considering for RVT if conventional medical treatment has failed.

Pulmonary Hypertension in Hemodialysis Patients Following Repeated Endovascular Thrombectomy.

BACKGROUND The prevalence of pulmonary hypertension is unusually high in Taiwanese patients with end-stage renal disease. Thrombosis of hemodialysis grafts is common and pulmonary embolism has been reported after endovascular thrombectomy. The aim of this study was to evaluate the relationship between pulmonary hypertension and endovascular thrombectomy of hemodialysis grafts. METHODS One hundred and ten patients on hemodialysis via arteriovenous grafts were enrolled in our study. The mean pulmonary artery pressure (PAP) was measured by right heart catheterization. Clinical information was collected by review of medical records. Comorbid cardiopulmonary disease was evaluated by echocardiography and chest X-ray. The history of patient vascular access thrombosis was reviewed from database, hemodialysis records, and interviews with staff at hemodialysis centers. RESULTS Fifty-two participants (47%) had pulmonary hypertension diagnosed by right heart catheterization. There was no difference in the number of thrombectomy procedures between patients with and without pulmonary hypertension. Based on multivariate analysis, the number of prior endovascular thrombectomy procedures did not correlate with mean PAP (F-value = 1.10, p = 0.30) nor was it associated with pulmonary hypertension (odds ratio = 0.92, p = 0.17). CONCLUSIONS Prior endovascular arteriovenous graft thrombectomies were not associated with pulmonary hypertension or increased mean PAP in end-stage renal disease patients on maintenance hemodialysis.

Monocyte Chemoattractant Protein-1 Levels and Postangioplasty Restenosis of Arteriovenous Fistulas

BACKGROUND AND OBJECTIVES Inflammation is relevant in restenosis of atherosclerotic vascular diseases, but its role in dialysis arteriovenous fistula remains unknown. In animal studies, upregulation of monocyte chemoattractant protein-1 has been shown in venous segments of arteriovenous fistula. We, therefore, aimed to investigate serial changes in circulating monocyte chemoattractant protein-1 after percutaneous transluminal angioplasty of dialysis arteriovenous fistulas and its relation to restenosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Fifty-nine patients with dysfunctional arteriovenous fistulas that were referred for percutaneous transluminal angioplasty were enrolled prospectively between January of 2010 and July of 2012. Three of them were excluded due to percutaneous transluminal angioplasty failure or acute infection. Blood was sampled from arteriovenous fistulas at baseline, 2 days, 2 weeks, and 3 months after percutaneous transluminal angioplasty. Clinical follow-up was continued monthly for 3 months. Angiographic follow-up was arranged at the end of 3 months. Seventeen patients without significant stenosis were enrolled as the control group. RESULTS Fifty-six patients completed clinical follow-up. Significant increases in monocyte chemoattractant protein-1 were observed at 2 days and 2 weeks (both P<0.001) after percutaneous transluminal angioplasty. Twenty-three (41%) patients had symptomatic restenosis. The restenosis group had a higher percentage change in monocyte chemoattractant protein-1 levels at 2 days (median =47%; interquartile range, 27%-65% versus median =17%; interquartile range, 10%-25%; P<0.001) after percutaneous transluminal angioplasty compared with the patent group. Fifty-two patients completed angiographic follow-up. A positive correlation between relative luminal loss and monocyte chemoattractant protein-1 increase at 2 days after percutaneous transluminal angioplasty was found (r=0.53; P<0.001). In multivariate analysis, postangioplasty monocyte chemoattractant protein-1 increase at 2 days was an independent predictor of restenosis. Using receiver operator characteristic analysis, >25% postangioplasty increase of monocyte chemoattractant protein-1 was significantly associated with restenosis after percutaneous transluminal angioplasty (hazard ratio, 5.36; 95% confidence interval, 1.81 to 15.8). CONCLUSIONS Circulating monocyte chemoattractant protein-1 levels were elevated 2 days and 2 weeks after percutaneous transluminal angioplasty. Early postangioplasty increase of monocyte chemoattractant protein-1 level was associated with restenosis of arteriovenous fistulas.

Feasibility and Safety of Coronary Procedures via an Arteriovenous Graft Approach in Patients on Maintenance Hemodialysis.

BACKGROUND Traditionally, a radial or brachial arterial approach is unadvisable in hemodialysis patients. Consequently, coronary angiography or angioplasty is usually performed via a femoral artery approach in these patients, who carry a higher risk of vascular access complications. In hemodialysis patients, arteriovenous grafts (AVG) are created for repeated punctures; however, the feasibility and safety of a trans-AVG approach for coronary angiography or angioplasty remains unclear. METHODS In our institution, cardiac catheterizations were attempted via AV grafts in hemodialysis patients with a U-shaped forearm AVG. We retrospectively identified coronary angiography or angioplasty procedures in hemodialysis patients from a computer-based database in our hospital. The procedure details and outcomes were obtained from review of the clinical, angiographic and hemodialysis records. RESULTS From 2008 to 2013, 167 procedures in hemodialysis patients were identified from 2866 diagnostic or interventional coronary procedures in our institution. Out of these, 24 procedures in 17 patients were performed via a trans-AVG approach. In all AVG procedures, a 6F 16-cm or 7F 10-cm sheath was placed from the AVG into the brachial artery. All diagnostic procedures were successfully performed. In 14 procedures, the patients also underwent angioplasty and all of the angioplasty procedures were successful. There was no arterial spasm, arterial dissection, puncture site hematoma, or acute thrombosis of the AVG during or after the procedures. CONCLUSIONS A trans-AVG approach appears to be a feasible and safe route for coronary angiography or angioplasty in hemodialysis patients with a U-shaped forearm AVG. However, further studies with a larger patient number are necessary. KEY WORDS Arteriovenous graft; Hemodialysis; Percutaneous coronary intervention.

A very-late migrated coronary stent mimicking aortic root vegetation

A 77-year-old man developed fever, dyspnoea, and bilateral lung oedema over a 3 days course. Echocardiography found an elongated hyperechoic mass protruding from the aortic wall near left coronary cusp, oscillating in the aortic root ( Panel A , Supplementary material online, Video S1 ). No significant valvular dysfunction or intra-cardiac thrombus was found. The blood cultures grew methicillin-resistant Staphylococcus aureus . Despite of adequate antibiotics coverage, the patient progressed into …