There are currently near 400 000 patients on hemodialysis in the United States. More than 50% of those treated by chronic hemodialysis die because of a cardiovascular (CV) event. The majority of ...these patients have functional arteriovenous fistulas (AVFs). AVFs have an adverse effect on cardiac function, but their exact contribution to CV morbidity is not clear. It has long been known that a vascular access with an inappropriately high‐flow rate may cause high‐output heart failure. Paradoxically, there may be hemodynamic and cardiopulmonary benefits conferred by AVF particularly in severe chronic obstructive pulmonary disease. While Brescia‐Cimino`s basic idea of the AVF has saved millions of lives, we would like to stress that there are dangers from their often high blood flow rates, which unfortunately have proved difficult to evaluate.
Intradialytic hypotension (IDH) is a frequent and serious complication of chronic haemodialysis, linked to adverse long-term outcomes including increased cardiovascular and all-cause mortality. IDH ...is the end result of the interaction between ultrafiltration rate (UFR), cardiac output and arteriolar tone. Thus excessive ultrafiltration may decrease the cardiac output, especially when compensatory mechanisms (heart rate, myocardial contractility, vascular tone and splanchnic flow shifts) fail to be optimally recruited. The repeated disruption of end-organ perfusion in IDH may lead to various adverse clinical outcomes affecting the heart, central nervous system, kidney and gastrointestinal system. Potential interventions to decrease the incidence or severity of IDH include optimization of the dialysis prescription (cool dialysate, UFR, sodium profiling and high-flux haemofiltration), interventions during the dialysis session (midodrine, mannitol, food intake, intradialytic exercise and intermittent pneumatic compression of the lower limbs) and interventions in the interdialysis period (lower interdialytic weight gain and blood pressure-lowering drugs). However, the evidence base for many of these interventions is thin and optimal prevention and management of IDH awaits further clinical investigation. Developing a consensus definition of IDH will facilitate clinical research. We review the most recent findings on risk factors, pathophysiology and management of IDH and, based on this, we call for a new consensus definition of IDH based on clinical outcomes and define a roadmap for IDH research.
Conventional hemodialysis (HD) (a 4 h session three times a week) is not appropriate for everyone and is excessive in the presence of substantial residual kidney function (RKF). However, it can be ...safely replaced by a softer incremental approach guided by the urea kinetic model (UKM), starting with one or two sessions a week. Observational data suggest that RKF may be lost less quickly if dialysis is initiated less frequently than 3 times a week. Incremental HD means that, in the presence of substantial RKF, kidney replacement therapy can begin with low doses and/or frequencies, which, however, must be adequately increased to compensate for any subsequent losses of RKF, keeping the total clearance level (kidney + dialysis) always above the minimum levels of adequacy. In HD, there are complexities in combining the dialysis dose with RKF, but tools have been developed to facilitate this issue. The literature findings lend support to the safety of incremental HD and highlight the potential for this method to be implemented as a new standard of care in dialysis patients with substantial RKF. Ongoing and future trials will likely generate further evidence of the clinical and healthcare benefits of incremental HD in routine practice.
Symptomatic intradialytic hypotension is a common complication of hemodialysis (HD). The application of convective therapies to the outpatient setting may improve outcomes, including intradialytic ...hypotension. In this multicenter, open-label, randomized controlled study, we randomly assigned 146 long-term dialysis patients to HD (n = 70), online predilution hemofiltration (HF; n = 36), or online predilution hemodiafiltration (HDF; n = 40). The primary end point was the frequency of intradialytic symptomatic hypotension (ISH). Compared with the run-in period, the frequency of sessions with ISH during the evaluation period increased for HD (7.1 to 7.9%) and decreased for both HF (9.8 to 8.0%) and HDF (10.6 to 5.2%) (P < 0.001). Mean predialysis systolic BP increased by 4.2 mmHg among those who were assigned to HDF compared with decreases of 0.6 and 1.8 mmHg among those who were assigned to HD and HF, respectively (P = 0.038). Multivariate logistic regression demonstrated significant risk reductions in ISH for both HF (odds ratio 0.69; 95% confidence interval 0.51 to 0.92) and HDF (odds ratio 0.46, 95% confidence interval 0.33 to 0.63). There was a trend toward higher dropout for those who were assigned to HF (P = 0.107). In conclusion, compared with conventional HD, convective therapies (HDF and HF) reduce ISH in long-term dialysis patients.
Background In bicarbonate-based hemodialysis, dialysate total calcium (tCa) concentration may have effects on mineral metabolism. Study Design Randomized crossover trial of 3 dialysate tCa ...concentrations (2.5, 2.75, and 3.0 mEq/L). Setting & Participants 22 stable anuric uremic patients underwent three 4-hour bicarbonate hemodialysis sessions with the 3 different dialysate tCa concentrations using a single-pass batch dialysis system. Outcomes Hourly measurements of plasma water ionized calcium (iCa) and plasma parathyroid hormone (PTH) concentrations. tCa mass balances were measured from the dialysate side. Results Hourly plasma water iCa concentrations were higher with a dialysate tCa concentration of 3.0 compared with 2.75 and 2.5 mEq/L ( P < 0.05), as were iCa concentrations at the end of dialysis sessions (2.66 ± 0.1, 2.56 ± 0.12, and 2.4 ± 0.08 mEq/L, respectively; P < 0.001). Mean tCa mass balance values (diffusion gradient from the dialysate to the patient) were positive with all dialysate tCa concentrations and increased progressively with dialysate tCa concentration (75 ± 122, 182 ± 125, and 293 ± 228 mg, respectively; P < 0.001). Plasma PTH levels increased during dialysis using dialysate tCa concentration of 2.5 mEq/L (mean increase, 225 ± 312 pg/mL) and decreased with dialysate tCa concentrations of 2.75 and 3.0 mEq/L (mean decreases, 68 ± 325 and 99 ± 432 pg/mL, respectively). Limitations Small sample size and lack of measurement of total-body calcium mass balances. Conclusions A dialysate tCa concentration of 2.75 mEq/L might be preferable to 2.5 or 3.0 mEq/L because it is associated with mildly positive tCa mass balance values, plasma water iCa levels in the reference range, and stable PTH levels during dialysis.
Acutely decompensated heart failure (HF) in patients with diuretic resistance is often treated with extracorporeal ultrafiltration. Peritoneal ultrafiltration (PUF) has been proposed for the ...long-term management of severe HF after resolution of the acute episode. The aim of the present study was to evaluate the use of PUF in the treatment of chronic refractory HF in patients without end-stage renal disease. ♢
This multicenter (10 nephrology departments throughout Italy) retrospective observational study included patients with severe HF refractory to maximized drug treatment. The patients were proposed for PUF because they had experienced at least 3 hospital admissions in the preceding year for acutely decompensated HF requiring extracorporeal ultrafiltration. ♢
Of the 48 study patients (39 men, 9 women; mean age 74 ± 9 years), 30 received 1 nocturnal icodextrin exchange, 5 required 2 daily exchanges, and 13 received 2 - 4 sessions per week of automated peritoneal dialysis. During the first year, renal function remained stable (initial: 20.8 ± 10.0 mL/min/1.73 m(2); end: 22.0 ± 13.6 mL/min/1.73 m(2)), while pulmonary artery systolic pressure declined to 40 ± 6.09 mmHg from 45.5 ± 9.18 mmHg (p = 0.03), with a significant concomitant improvement in New York Heart Association functional status. Hospitalizations decreased to 11 ± 17 days/patient-year from 43 ± 33 days/patient-year before the start of PUF (p < 0.001). The incidence of peritonitis was 1 episode in 45 patient-months. Patient survival was 85% at 1 year and 56% at 2 years. ♢
This study confirms the satisfactory results of using PUF for chronic HF in elderly patients.
PDF
