Impact of Bioelectrical Impedance-Guided Fluid Management and Vitamin D Supplementation on Left Ventricular Mass in Patients Receiving Peritoneal Dialysis: A Randomized Controlled Trial.

RATIONALE & OBJECTIVE: Hypervolemia and vitamin D deficiency occur frequently in patients receiving peritoneal dialysis and may contribute to left ventricular (LV) hypertrophy. The effect of bioelectrical impedance analysis (BIA)-guided volume management or vitamin D supplementation on LV mass among those receiving peritoneal dialysis is uncertain. STUDY DESIGN: Two-by-two factorial randomized controlled trial. SETTING & PARTICIPANTS: Sixty-five patients receiving maintenance peritoneal dialysis. INTERVENTION: BIA-guided volume management versus usual care and oral cholecalciferol 50,000 U weekly for 8 weeks followed by 10,000 U weekly for 44 weeks or matching placebo. OUTCOME: Change in LV mass at 1 year measured by cardiac magnetic resonance imaging. RESULTS: Total body water decreased by 0.9 + 2.4 (SD) L in the BIA group compared with a 1.5 ± 3.4 L increase in the usual care group (adjusted between-group difference: -2.4 [95% CI, -4.1 to -0.68] L, P = 0.01). LV mass increased by 1.3 ± 14.3 g in the BIA group and decreased by 2.4 ± 37.7 g in the usual care group (between-group difference: +2.2 [95% CI, -13.9 to 18.3] g, P = 0.8). Serum 25-hydroxyvitamin D concentration increased by a mean of 17.2 ± 30.8 nmol/L in the cholecalciferol group and declined by 8.2 ± 24.3 nmol/L in the placebo group (between-group difference: 28.3 [95% CI, 17.2-39.4] nmol/L, P < 0.001). LV mass decreased by 3.0 ± 28.1 g in the cholecalciferol group and increased by 2.0 ± 31.2 g in the placebo group (between-group difference: -4.5 [95% CI, -20.4 to 11.5] g, P = 0.6). LIMITATIONS: Relatively small sample size with larger than expected variation in change in LV mass. CONCLUSIONS: BIA-guided volume management had a modest impact on volume status with no effect on the change in LV mass. Vitamin D supplementation increased serum vitamin D concentration but had no effect on LV mass. FUNDING: Unrestricted Baxter International extramural grant and the Kidney Foundation of Canada. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT01045980.

The fluid study protocol: a randomized controlled study on the effects of bioimpedance analysis and vitamin D on left ventricular mass in peritoneal dialysis patients.

OBJECTIVES: We will evaluate the effects of bioimpedance analysis-guided fluid management to reduce volume expansion, of vitamin D(3) supplementation, and of the combination of those techniques on decrease of left ventricular mass in peritoneal dialysis (PD) patients. DESIGN: This multicenter randomized controlled trial, with a 2 × 2 factorial design, will be conducted at PD clinics affiliated with 3 Canadian teaching hospitals. Consenting PD patients 18 years of age or older will be included. Patients will be excluded if they have contraindications to bioimpedance or magnetic resonance imaging, life or technique expectancy of less than 1 year, peritonitis within the preceding 3 months, or serum calcium above 2.55 mmol/L. INTERVENTION: The study will randomize 70 patients to bio-impedance-guided volume management or to usual care and to vitamin D(3) 50,000 U weekly for 8 doses, and then 10,000 U weekly or to matching placebo. MAIN OUTCOME MEASURES: The primary outcome will be change in left ventricular mass at 1 year as determined by cardiac magnetic resonance imaging. The secondary outcome will be a composite endpoint of death, nonfatal cardiovascular event, and transfer to hemodialysis for dialysis inadequacy or ultrafiltration failure. Other outcome measures will include blood pressure, quality of life, 6-minute walk test, inflammatory and fibrotic markers and their association with peritoneal membrane transport properties, and residual renal function. Patients will be followed for clinical outcomes for up to 3 years. CONCLUSIONS: This study will assess whether bioimpedance-directed volume management and vitamin D(3) supplementation can improve left ventricular mass in PD patients.

Non-invasive characterization of the area-at-risk using magnetic resonance imaging in chronic ischaemia.

AIMS: we investigated the performance of quantitative stress perfusion magnetic resonance imaging (MRI) as a basis for identifying and characterizing the area-at-risk subtending a chronic coronary artery (CA) stenosis. METHODS AND RESULTS: pigs underwent a percutaneous copper-coated stent implantation in the circumflex CA (n = 11) or a sham operation (n = 5). After 6 weeks, angiography and MRI were performed including cine (rest, low- and high-dose dobutamine stress), dual-bolus first-pass perfusion (rest and adenosine stress), and contrast-enhanced imaging to quantify myocardial infarction (MI). Myocardial blood flow (MBF) was quantified based on Fermi-model deconvolution and compared with microsphere measurements. On the basis of Evan's blue staining, MBF thresholds to define the area-at-risk were determined by receiver-operating characteristic (ROC) analysis. CA stenosis was 94 ± 7% and infarct size (IS) 7.3 ± 3.1% of left ventricular mass. Segmental thresholds of hyperaemic MBF yielded the best performance for detecting area-at-risk. There was a good correlation between MRI and microsphere perfusion (r(2) = 0.84, P < .0001). The area-at-risk presented a mixed substrate of non-infarcted (non-MI), <50% infarcted (MI+), and >50% infarcted (MI++) segments. MBF was reduced in at-risk vs. remote segments at rest (non-MI, 0.50 ± 0.21; MI+, 0.47 ± 0.14; MI++, 0.42 ± 0.14; remote, 0.84 ± 0.25 mL/min/g) and during stress (non-MI, 0.69 ± 0.09; MI+, 0.66 ± 0.14; MI++, 0.51 ± 0.11; remote, 1.70 ± 0.36 mL/min/g). Segmental wall thickening showed different responses to stress (remote, progressive increase during incremental stress; non-MI, increase at low-dose and discontinued at high-dose; MI+, initial increase and decrease at high-dose; MI++, progressive decrease). CONCLUSION: quantitative hyperaemic perfusion MRI accurately defines segments in the area-at-risk in chronic ischaemia, which present with different functional response to stress related to segmental IS.