Regional citrate anticoagulation vs systemic heparin anticoagulation for double-filtration plasmapheresis.

INTRODUCTION: Double-filtration plasmapheresis (DFPP) has been utilized for immunomodulation in kidney transplantation. Anticoagulation is important to maintain circuit patency during DFPP. We aimed to compare the efficacy and safety of regional citrate anticoagulation (RCA) with systemic heparin anticoagulation during DFPP in kidney transplant recipients. METHODS: A retrospective cohort study was conducted to compare the efficacy and safety of RCA (RCA-DFPP) to systemic heparin anticoagulation (Hep-DFPP) for DFPP among kidney transplant recipients in a single tertiary center. RESULTS: A total of 112 sessions of DFPP were performed for 23 subjects, of which 62 sessions were RCA-DFPP and 50 sessions were Hep-DFPP. There were 13 sessions (11.6%) of premature circuit clotting, 10 sessions (16.1%) for RCA-DFPP and 3 sessions (6.0%) for Hep-DFPP (P = .10). All premature circuit clotting episodes occurred in subjects who underwent DFPP through a vascular catheter. Premature circuit clotting was associated with the use of a vascular catheter (odds ratio [OR] 14.2, 95% confidence interval [CI] 2.7-73.7; P < .01) and high postfilter ionized calcium (OR 12.7, 95% CI 1.4-112.5; P < .01). There was no major bleeding event. Hep-DFPP was associated with higher occurrence of hypocalcemia (OR 1.1, 95% CI 1.0-1.2; P < .01) and metabolic acidosis (OR 1.4, 95% CI 1.2-2.0; P = .04), while hypomagnesemia was more common for RCA-DFPP (OR 2.9, 95% CI 1.1-7.4; P = .03). CONCLUSION: Amongst kidney transplant patients who receive DFPP therapy, RCA-DFPP may be comparable to Hep-DFPP for the maintenance of circuit patency. Functioning vascular access is vital in avoiding premature clotting of the circuit. Close monitoring of electrolyte imbalances and coagulopathy related to DFPP is recommended.

Regional Citrate Anticoagulation during Double-Filtration Plasmapheresis in Kidney Transplant Recipients: A Single-Center Retrospective Cohort Study.

INTRODUCTION: Double-filtration plasmapheresis (DFPP) may be used for immunomodulation in kidney transplant (KTx). While DFPP reduces plasma product exposure, risk of circuit clotting merits adequate anticoagulation. Regional citrate anticoagulation (RCA) avoids the risks of systemic anticoagulation, but a protocol for RCA-DFPP is not previously widely described. METHODS: We conducted a single-center retrospective cohort study involving adult (≥21 years old) KTx recipients who underwent RCA-DFPP from 2018 to 2020 to investigate efficacy and safety for an RCA protocol during DFPP in KTx recipients. RESULTS: Fifty-one (85%) of 60 RCA-DFPP sessions in 17 patients completed without circuit clotting. Circuit clotting was associated with high post-filter ionized calcium (28 vs. 3.7%, odds ratio 10.1, 95% CI 1.1-89.4, p = 0.037). Hypo- and hypercalcemia developed in 5 (8.3%) and 8 (13.3%) sessions, respectively, but no adverse effects were noted despite severe hypocalcemia in one. There was no significant change in pre- and post-RCA-DFPP sodium, bicarbonate, albumin, and platelet levels. With regards DFPP procedure, prolongation of prothrombin time (PT) and activated partial thromboplastin time (aPTT) was observed following 38 (64.4%) and 12 (20.3%) sessions, respectively. Severely prolonged (>1.5 × upper limit normal) PT and aPTT were recorded in 2 sessions each. Expectedly, hypofibrinogenemia developed after 31 (51.7%) sessions: including 4 (6.7%) severe hypofibrinogenemia (<0.5 g/L). Two patients developed bleeding requiring blood product transfusion. The median total volume of fluids administered per session was 1.495 (1.373-1.612) L; post-RCA-DFPP significant weight gain of 0.5 (0-1.25) kg was noted. Diuretic was commenced or dose increased following 20 (33.3%) sessions for fluid balance management. DISCUSSION/CONCLUSION: Protocol-based RCA for DFPP is feasible and safe in KTx recipients. However, DFPP-related coagulopathy can develop consequent to treatment; caution should be exercised for patients with bleeding risk. Close monitoring and management of the patients' electrolytes, especially hypocalcemia and hypomagnesemia, and fluid status is recommended.

Effect of short-term low molecular weight heparin on patency following successful salvage of arteriovenous access with recurrent thrombosis.

AIM: This study aims to investigate the effect of low molecular weight heparin (LMWH) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis. METHODS: Following successful thrombectomy, 66 patients with recurrent thrombosis were included in the study. The primary, assisted primary and secondary patency rates of patients who received LMWH (n = 24) were compared with those who did not receive anticoagulant (n = 42) using Kaplan-Meier analysis. Cox-regression analysis was performed to investigate potential predictors of patency rates. RESULTS: The mean dose of enoxaparin used was 40 ± 13.1 mg or 0.74 ± 0.2 mg/kg daily for a median duration of 14 (IQR 7,28) days. The mean trough anti-Xa concentrations measured after two doses of LMWH was 0.17 ± 0.13 IU/mL. Kaplan-Meier analyses for mean primary, assisted primary and secondary patency rates of LMWH vs no anticoagulation groups were 149 (95% CI: 91 - 207) vs 87 (95% CI: 42-132) days (P < .006), 230 (95% CI: 142-320) vs 107 (95% CI: 62-150) days (P = .01) and 438 (299-579) vs 294 (95% CI: 197-392) days (P = .08) respectively. LMWH remained a significant protective predictor of primary (HR: 0.49; 95% CI: 0.25-0.86; P = .02) and assisted primary patency rates (HR: 0.51; 95% CI: 0.27-0.98; P = .04) after adjusting for patient age, access age, type of AV access, presence of peripheral vascular disease and haemoglobin levels. CONCLUSION: LMWH may improve short and mid-term patency rates for AV accesses with recurrent thrombosis.

Outcomes of endovascular salvage of clotted arteriovenous access and predictors of patency after thrombectomy.

OBJECTIVE: This study aimed to report the outcomes of endovascular salvage of clotted arteriovenous (AV) accesses and to determine potential predictors of poor patency rates after thrombectomy. METHODS: Records of hemodialysis patients who underwent endovascular salvage of clotted AV access were reviewed retrospectively. Technical and clinical success rates, complication rates, and 3- and 6-month patency rates were determined. Multivariate analysis was performed to determine the predictors of patency after thrombectomy. RESULTS: A total of 294 patients underwent endovascular salvage of clotted AV access during the study period; 156 patients had arteriovenous fistula, whereas the remaining 138 were arteriovenous grafts (AVGs). The technical and clinical success rates were 96.3% and 93.2%; the major and minor complication rates were 0.7% and 9.9%. Post-thrombectomy primary, assisted primary, and secondary patency rates were 62.9%, 76.2%, and 77.6% at 3 months and 43.9%, 59.5%, and 61.6% at 6 months. The patency rates were significantly better for arteriovenous fistula than for AVG except for 6-month assisted primary and secondary patency. Multivariate Cox regression analysis showed that prior thrombosis within 90 days was significantly associated with loss of primary patency (hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.21-2.98; P < .01), assisted primary patency (HR, 2.42; 95% CI, 1.42-4.13; P < .01), and secondary patency (HR, 2.52; 95% CI, 1.40-4.53; P < .01). Having an AVG was also negatively associated with primary patency. CONCLUSIONS: Most clotted AV accesses can be salvaged by endovascular technique. Recurrent thrombosis within 90 days is associated with poor short- and long-term patency even after successful endovascular reinterventions.

Paclitaxel-coated balloon in the treatment of recurrent dysfunctional arteriovenous access, real-world experience and longitudinal follow up.

AIM: Dysfunctional arteriovenous (AV) access remains a significant cause of morbidity and hospital admission for patients with end stage renal failure on haemodialysis. This study was performed to evaluate the impact of paclitaxel-coated Balloon (PCB) on the patency of AV access with recurrent stenoses. METHODS: We retrospectively studied haemodialysis patients who presented to our centre with recurrent AV access dysfunction and compared intervention-free patency using plain balloon versus PCB. RESULTS: A total of 147 patients were followed up longitudinally. Intervention-free patency was better following PCB compared to previous intervention using plain balloons (6.4 ± 5.8 versus 4.0 ± 3.7, P < 0.01). The 3- and 6-month patency rates after PCB were significantly better compared to standard plain angioplasty balloon: 69.4% versus 52.4%, P < 0.01 and 42.9% versus 15.6%, P < 0.01 respectively. Kaplan-Meier survival analysis of circuit patency demonstrated the superiority of PCB over plain balloon angioplasty in both arteriovenous fistula and arteriovenous graft (P < 0.01 and P = 0.01 respectively) although the patency of arteriovenous fistula remained significantly better than arteriovenous graft following interventions with PCB (P < 0.01). Age of AV access and the number of previous interventions were found to be significant predictors of patency following PCB intervention. CONCLUSION: Arteriovenous access intervention with PCB was shown to be superior compared to plain balloon in the treatment of both non-thrombosed and thrombosed AV accesses in our multi-ethnic population.

Impact of simulation-based learning on immediate outcomes of temporary haemodialysis catheter placements by nephrology fellows.

AIM: Traditional apprenticeship model (AM) of teaching in invasive procedures such as temporary haemodialysis catheter (THDC) insertion can result in propagation of errors and complications. Simulation-based learning (SBL) offers standardization of skills and allows trainees to repeatedly practice invasive procedures prior to performing them on actual patient. METHODS: Retrospective cohort study of first-, second- and third-year Nephrology Fellows from a tertiary teaching hospital from September 2008 to September 2015. The intervention group (n = 9) received simulation training in ultrasound-guided THDC placement. The historical control group (n = 12) received training through traditional AM. The primary and secondary outcomes were the immediate complications and success rates of THDC insertion. RESULTS: A total of 2481 THDCs were placed in 1787 patients. Success rate of internal jugular THDC placement for AM vs. SBL Fellow was 99.8% versus 100% (P = 0.90), while the success rate for femoral THDC placement was 99.6% versus 99.2% (P = 0.53). SBL Fellows reported fewer overall peri-procedure complications (8.3% vs. 11.2%, P = 0.02) and mechanical complications (1% vs. 2.4%, P = 0.02) compared to AM Fellows. The rate of reported technical difficulty was similar (7.5% vs. 9.2%, P = 0.17). After adjusting for side and site of THDC placement, body mass index and laboratory indices, THDC inserted by AM Fellows were independently associated with increased overall peri-procedure complications (OR = 1.396, 95% CI: 1.052-1.854, P = 0.02) and mechanical complications (OR = 2.481, 95% CI: 1.178-4.810, P = 0.02). CONCLUSIONS: Simulation-based learning was associated with lower procedure related complications and should be an integral component in the teaching of procedural skills in Nephrology.

A Case of Spontaneous Perinephric Hematoma From Rivaroxaban.

Spontaneous perinephric hematoma is an uncommon but serious condition that is typically caused by tumor hemorrhage or vascular disease such as polyarteritis nodosa. We describe a 78-year-old Chinese gentleman with underlying chronic kidney disease, renal cysts, non-obstructive renal stones, hypertension, ischemic heart disease, and atrial fibrillation who was on rivaroxaban and clopidogrel. He developed spontaneous perinephric hematoma complicated by acute kidney injury, anemia, and myocardial infarction who underwent angioembolization and packed cell transfusion. He did not have further bleeding episodes, and his kidney function improved before discharge.

Hypertriglyceridemia-induced pancreatitis in pregnancy: case review on the role of therapeutic plasma exchange.

SUMMARY: Gestational hypertriglyceridemia-induced pancreatitis is associated with significant maternal and fetal morbidity and mortality. We report a case of gestational hypertriglyceridemia-induced pancreatitis in a primigravida at 31-weeks gestation, complicated by impending preterm labor and metabolic acidosis requiring hemodialysis. This was successfully managed with therapeutic plasma exchange (TPE), followed by i.v. insulin, low-fat diet, and omega-3. Triglyceride levels stabilized after TPE and the patient underwent an uncomplicated term delivery. In pregnancy, elevated estrogen and insulin resistance exacerbate hypertriglyceridemia. Management is challenging as risks and benefits of treatment options need to be weighed against fetal wellbeing. We discuss management options including a review of previous case reports detailing TPE use, dietary optimization, and delivery timing. This case emphasizes the importance of multidisciplinary care to optimize maternal and fetal outcomes. LEARNING POINTS: Gestational hypertriglyceridemia-induced pancreatitis has high morbidity. A multidisciplinary team approach is a key as maternal and fetal needs must be addressed. Rapid lowering of triglycerides is crucial and can be achieved successfully and safely with plasma exchange. A low-fat diet while ensuring adequate nutrition in pregnancy is important. Timing of delivery requires consideration of fetal maturity and risk of recurrent pancreatitis.

Comparison of alteplase and urokinase for pharmacomechanical thrombolysis of clotted hemodialysis access.

BACKGROUND: Percutaneous pharmacomechanical thrombolysis is increasingly used to salvage thrombosed hemodialysis access. We aim to evaluate the effectiveness of alteplase compared to urokinase in percutaneous pharmacomechanical thrombolysis clotted access. METHODS: Records of patients who underwent pharmacomechanical thrombolysis at Interventional Nephrology Suite in a tertiary teaching hospital from 1 January 2016 to 31 December 2016 were reviewed. Technical and clinical success rates, thrombosis-free and cumulative survivals, procedure time, and radiation dose imparted to patients were compared for pharmacomechanical thrombolysis with urokinase versus alteplase. RESULTS: A total of 122 incident patients underwent pharmacothrombolysis (n = 53 for urokinase, n = 69 for alteplase) during the study period. The mean dose of urokinase and alteplase used was 176,897 ± 73,418 units and 3.7 ± 0.8 mg, respectively. Pharmacomechnical thrombolysis using urokinase versus alteplase has similar technical success rate (98.1% vs 97.1%, p = 0.599), clinical success rate (88.7% vs 97.1%, p = 0.068), complication rate (9.4% vs 13.0%, p = 0.373), and primary patency rates at 3 months (57.1% vs 70.1%, p = 0.106). Thrombosis-free survivals of the vascular access were 113.2 (35.3, 196) days versus 122 (84, 239) days (p = 0.168). Cumulative survivals were 239 (116, 320) vs 213 (110.5, 316.5) days (p = 0.801). Procedure time, fluoroscopy time, skin dose, and dose were significantly lower for pharmacomechanical thrombolysis using alteplase compared to urokinase (p = 0.045, p < 0.0001, p = 0.006, p = 0.001, respectively). Stenting was found to be associated with successful dialysis following thrombolysis on univariate analysis (odds ratio: 9.167, 95% confidence interval: 1.391-19.846, p = 0.021), although this was no longer significant in multivariate analysis (p = 0.078). CONCLUSION: Alteplase is an effective and safe alternative to urokinase for pharmacomechanical thrombolysis of clotted vascular access.

Metastatic pulmonary calcification: Experience from a single center in Singapore.

Metastatic pulmonary calcification (MPC) was seen in 79% of patients with end-stage renal disease (ESRD) during autopsy. However, it is not commonly diagnosed in vivo. Its pathogenesis is not fully understood. We report a retrospective series of 5 cases of MPC from a single center in Singapore. MPC were diagnosed using radiological or histological features. Mean onset of MPC from diagnosis of ESRD was 22.6 ± 3.1 years. One patient remains asymptomatic. Four patients died, one was related to MPC. All patients had calcifications at the lung apices on radiological studies. Three patients with MPC were diagnosed based on radiological features while 2 had histological features. Four patients underwent parathyroidectomy without radiological changes before parathyroidectomy. Median intact parathyroid hormone of this series was 5.6 pmol/L (IQR 1.3-139.4), alkaline phosphatase 74 U/L (IQR 62-461), calcium 2.10 mmol/L (IQR 1.85-2.40), and phosphate 1.30 mmol/L (IQR 0.87-1.63). The observed low iPTH suggests that MPC might occur in low iPTH. Our case series showed MPC might occur in low iPTH after parathyroidectomy, in contrast to existing literature that suggests MPC is diagnosed in patients with elevated iPTH. Parathyroidectomy does not prevent MPC.