Thierry Petitclerc

End‐stage renal failure and cardiac mortality after heart transplantation

Abstract:  Background:  Coronary artery disease (CAD) is the leading cause of mortality after the first year of heart transplantation. End‐stage renal failure (ESRF) is more frequent because of long‐term survival. Impact of ESRF on cardiac mortality in heart transplant patients is unappreciated. The hypothesis of accelerated CAD in uremic patients has been suggested.

Sodium management in dialysis by conductivity.

The determination of dialysate sodium concentration is one of the challenges of dialysis prescription, because no accurate information on the predialytic sodium overload is available. Too low dialysate sodium is responsible for intradialytic intolerance symptoms, whereas too high sodium may lead to long-term water sodium overload with cardiovascular hazards (hypertension, left heart failure). We propose here a biofeedback system based on noninvasive repeated measures of ionic dialysance and plasma water conductivity used here as a surrogate of plasma water sodium. This system achieves a stable postdialytic sodium pool and subsequently a dialysate sodium concentration adapted to the inter dialytic sodium load. This new tool in dialysate sodium prescription aims at reducing the morbidity related to patient sodium balance impairment.

Ionic dialysance: principle and review of its clinical relevance for quantification of hemodialysis efficiency.

Ionic dialysance (D) is an online measured variable now available on several dialysis monitors to evaluate small‐solute clearance. Based on conductivity measurements in the inlet and outlet dialysate, the principle of the measurement and the different measurement methods are described. Studies that have evaluated the reliability of ionic dialysance to assess dialysis efficiency are discussed. These studies are divided into two groups: the first comparing ionic dialysance to urea clearance and the second comparing Dt/V to Kt/Vurea, in which the uncertainties of the measurement of Vurea could have misrepresented the relationship between Dt/V and Kt/Vurea. When Kt/Vurea via the Daugirdas second‐generation equation taking the rebound into account is considered, slight—even nonsignificant—differences are evidenced between Kt/Vurea and Dt/V. Therefore, ionic dialysance should be considered as a valid measure in future guidelines for dialysis efficiency.

Angiotensin-converting enzyme inhibitor-induced syndrome of inappropriate secretion of antidiuretic hormone: Case report and review of the literature

Seventeen cases of severe hyponatremia induced by angiotensin‐converting enzyme (ACE) inhibitor therapy have been reported in the literature. The mechanism of severe hyponatremia induced by ACE inhibitor is not clear. A 60‐year‐old white man with a history of idiopathic dilated cardiomyopathy was treated with enalapril, 20 mg daily, that had been started 2 weeks before heart transplantation. The serum sodium level was 138 mmol/L before initiation of enalapril therapy and 127 mmol/L just before cardiac surgery. In the post‐heart transplantation period, enalapril therapy was withdrawn for the perianesthesia period, and the serum sodium level increased from 127 to 140 mmol/L. One month later, viral myocarditis developed in the patient and enalapril was reintroduced at 20 mg daily. Two weeks later, natremia decreased. Enalapril was discontinued. Three days later the serum sodium level rose to 140 mmol/L. Severe symptomatic hyponatremia induced by the syndrome of inappropriate secretion of antidiuretic hormone should be considered a rare but possible complication associated with ACE inhibitor therapy.

Regional citrate anticoagulation during hemodialysis: a simplified procedure using Duocart biofiltration.

Background: Regional citrate anticoagulation during hemodialysis is promising, but its clinical implementation is routinely cumbersome because a continuous adjustment of calcium infusion at the dialyzer outlet is needed. Duocart biofiltration (DCB) is a new hemodialysis method using a calcium and magnesium-free dialysate containing only sodium chloride and bicarbonate combined with the infusion into the venous line of a solution containing the ionic complement (K, Ca, Mg) and glucose. Since the dialysate is calcium- and magnesium-free and infusion rate of the solution containing calcium is automatically determined by the dialysis delivery system according to the on-line measured value of ionic dialysance, DCB seems a technique especially suitable for citrate anticoagulation procedure. Methods: Thirty DCB sessions were performed in 10 patients with increased risk of bleeding. A commercially available mixture of trisodium citrate, citric acid and glucose was infused into the arterial line at a rate equal to 3% of dialyzer blood flow. The ionic complement (K: 48 mM, Ca: 42 mM, Mg: 14 mM, glucose: 110 mM) was infused at a rate equal to 1/24 ionic dialysance value automatically determined each 15 min by the dialysis monitor. DCB sessions were compared to 21 conventional bicarbonate hemodialysis (BHD) sessions with low-molecular-weight heparin anticoagulation. Results: Whole blood activated clotting time (WBACT) measured in the venous line (before infusion of ionic complement) was 200% of the WBACT value in the arterial line. Clotting and citrate-related adverse events were not observed. Postdialysis compression time of the arteriovenous access is significantly (p < 0.001) shorter after DCB sessions (3.9 ± 1.1 min) compared with BHD sessions (8.7 ± 4.6 min). Conclusion: Citrate anticoagulation during Duocart biofiltration is effective, safe and suitable for routine use because calcium infusion rate is automatically adjusted without the need of monitoring degree of anticoagulation and level of ionized calcium.

Effect of a plasma sodium biofeedback system applied to HFR on the intradialytic cardiovascular stability. Results from a randomized controlled study

Background Intradialytic hypotension (IDH) is still a major clinical problem for haemodialysis (HD) patients. Haemodiafiltration (HDF) has been shown to be able to reduce the incidence of IDH. Methods Fifty patients were enrolled in a prospective, randomized, crossover international study focussed on a variant of traditional HDF, haemofiltration with endogenous reinfusion (HFR). After a 1-month run-in period on HFR, the patients were randomized to two treatments of 2 months duration: HFR (Period A) or HFR-Aequilibrium (Period B), followed by a 1-month HFR wash-out period and then switched to the other treatment. HFR-Aequilibrium (HFR-Aeq) is an evolution of the haemofiltration with endogenous reinfusion (HFR) dialysis therapy, with dialysate sodium concentration and ultrafiltration rate profiles elaborated by an automated procedure. The primary end point was the frequency of IDH. Results Symptomatic hypotension episodes were significantly lower on HFR-Aeq versus HFR (23 ± 3 versus 31 ± 4% of sessions, respectively, P l= l0.03), as was the per cent of clinical interventions (17 ± 3% of sessions with almost one intervention on HFR-Aeq versus 22 ± 2% on HFR, P <0.01). In a post-hoc analysis, the effect of HFR-Aeq was greater on more unstable patients (35 ± 3% of sessions with hypotension on HFR-Aeq versus 71 ± 3% on HFR, P <0.001). No clinical or biochemical signs of Na/water overload were registered during the treatment with HFR-Aeq. Conclusions HFR-Aeq, a profiled dialysis supported by the Natrium sensor for the pre-dialysis Na+ measure, can significantly reduce the burden of IDH. This could have an important impact in every day dialysis practice.

Detection of Vascular Access Stenosis by Measurement of Access Blood Flow from Ionic Dialysance

Background/Aim: The measurement of the vascular access blood flow rate (Qa) in chronic hemodialyzed patients was proposed to predict access thrombosis. We have recently presented a new method based on the measurements of ionic dialysance at normal and reversed positions of the blood lines. We evaluate the reliability of the measurement of Qa by this method in detecting significant access stenoses. Methods: Twenty-five patients on chronic hemodialysis and having a vascular access cannulated with two needles were studied. The Qa was evaluated by the Diascan® ionic dialysance (Qa-id) method and by the ultrasound dilution technique (Qa-us; Transonic®) during the same dialysis session. The measurements were available for 23 patients. In addition, the patients had ultrasonography of their fistula followed by angiography, if a stenosis was detected. Results: Qa-id and Qa-us were not significantly different, showing a difference in Qa at 32 ± 469 ml/min. Qa-id was significantly different between patients with or without stenosis (508 ± 241 vs. 1,125 ± 652 ml/min, p < 0.05). Among patients with a Qa <500 ml/min by Qa-id, 5 had a stenosis detected by ultrasonography (sensitivity 83%), and 3 had no stenosis (false-positive rate 18%). Of these 3 patients, 2 had a thrombotic event at 1 and 3 months, suggesting that a more sensitive detection of stenosis for this range of Qa is needed and that a Qa <500 ml/min has a higher power to predict thromboses than a stenosis by ultrasonography. Conclusions: The measurement of the access flow rate by the Qa-id method has a clinical relevance to the detection of vascular access stenosis. An intervention program based on the Qa-id has to be evaluated.

Safe Use of Citric Acid-Based Dialysate and Heparin Removal in Postdilution Online Hemodiafiltration

Background: Anticoagulation of the blood circuit with heparin is essential for hemodialysis, but exposes patients to several risks (bleeding, thrombocytopenia, etc.). The use of citric acid-based dialysate (CitA-D) allows the reduction of heparin in conventional hemodialysis. We evaluated the feasibility of using CitA-D in postdilution online hemodiafiltration (OL-HDF) and of removing heparin. Methods: We prospectively compared chlorhydric acid-based dialysate with CitA-D in 10 patients treated by OL-HDF. First, we reduced heparin by half the dose and then we totally removed anticoagulation. Results: For all 120 sessions using heparin-free CitA-D, only one clotting episode related to an arteriovenous fistula stenosis was observed. No adverse clinical effect was observed. (Kt/V)sp, predialytic serum bicarbonate, calcium, phosphate, parathroid hormone, and β2-microglobulin remained the same in all cases. Conclusion: Our data suggest that the use of CitA-D in OL-HDF is safe and allows heparin removal in most patients.

Measuring Plasma Conductivity to Detect Sodium Load in Hemodialysis Patients

BACKGROUND Sodium thiosulfate therapy has been proposed for calcific uremic arteriolopathy and nephrogenic systemic fibrosis in hemodialysis patients. The treatment brings 3.7 g (161 mmol) of sodium. How to counterbalance this sodium load was studied. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Plasma conductivity (Cp) and mass balance index were compared for 20 sessions without thiosulfate and 20 sessions with thiosulfate infusion. Subsequently, the dialysate conductivity was set to 13.8 mS/cm during the entire session. Next, dialysate conductivity was set to 14 mS/cm for the first 3 h and to 13 mS/cm for the last hour of thiosulfate infusion (n = 25). RESULTS The Cp variation between beginning and end was equal to +0.005 +/- 0.13 mS/cm without thiosulfate, +0.24 +/- 0.13 mS/cm with thiosulfate, and 14 mS/cm dialysate conductivity (P < 0.001). The decrease in dialysate conductivity at 13.8 mS/cm did not counterbalance the sodium load. The last program adequately compensated the sodium load with a Cp increase of only +0.05 +/- 0.14 mS/cm (NS versus without thiosulfate). The total of the dialyzed sodium and the sodium load for this last program was equal to 603 mmol compared with 456 mmol for the sessions without thiosulfate, the difference of 147 mmol being close to the known content of 161 mmol in 25 g of infused thiosulfate. CONCLUSIONS Thiosulfate infusion requires a decrease of dialysate conductivity of -1 mS/cm during the infusion to counterbalance the added 3.7 g (161 mmol) sodium load.

Effect of mineralocorticoids on interdialytic weight gain in hemodialysis patients with perdialytic hypotension.

Fludrocortisone is recommended in patients with orthostatic hypotension and a benefit has been suggested in hemodialysis patients with severe hypokaliemia. We report 2 patients who suffered from chronic severe perdialytic hypotension resistant to midodrine and who were treated in a long‐term period with fludrocortisone. A rise of post‐dialytic BP was observed with a decrease of the interdialytic weight gain (IWG). We suggest that the IWG decrease is induced by a lessening of the renin angiotensin aldosterone system that could be less stimulated at the end of the dialysis session because of a better‐preserved arterial pressure. The decrease of angiotensin could lessen the feeling of thirst.