Ionized and total serum magnesium in hemodialysis: predictors and variability. A longitudinal cross-sectional study.

BACKGROUND: Ionized Magnesium (ion-Mg) represents the active biological fraction of the serum magnesium content. The assessment of total serum Mg (tot-Mg) might not accurately identify patients with hypo-or hyper-magnesaemie. In hemodialysis, serum tot-Mg levels in the upper part of the distribution, have been associated with reduced mortality and fewer vascular calcifications; thus, resulting in the tendency to increase the Mg concentration in the dialysate, traditionally set at 0.5 mmol/L. METHODS: Single-center study in chronic hemodialysis patients, designed in two phases, cross-sectional and longitudinal, aimed to investigate: (1) the sensitivity for pathological values of ion-Mg compared to tot-Mg (2) the predictors of ion-Mg developing ad hoc equations; (3) the inter- and intra-individual variabilities of ion-Mg; and (4) the risk factors for hypermagnesemia. Tot-Mg, ion-Mg, and covariates of 42 hemodialysis sessions, in 42 patients during the cross-sectional phase and of 270 sessions in 27 patients in the longitudinal one were analysed. RESULTS: Ion-Mg significantly correlates with tot-Mg: ß = 0.52; r = 0.88, p < 0.001. Multiple linear regressions in normo- and hypo-albuminemic patients gave the following results: ion-Mg = tot-Mg/2-K+/50 + Ca2+/5-HCO3-/100 and ion-Mg = tot-Mg/2 + albumin/100. Ion-Mg showed a high temporal variability in the longitudinal phase (between months p < 0.001; winter vs. summer, p < 0.027). A high intra-individual variability was also found: coefficient of variation 0.116. Comparing patients with high and low intra-individual variability, we found: age 67 vs. 77 years; p < 0.001; urea 26.3 ± 0.5 vs. 21.2 ± 0.4 mmol/L, p < 0.001; nPCR 0.92 ± 0.1 vs. 0.77 ± 0.1 g/kg day, p < 0.001; PTH 46.3 ± 4 vs. 28.5 ± 3 pmol/L, p < 0.001. CONCLUSIONS: Ion-Mg can be useful in unmasking unrecognized hyper- and hypo-magnesemic and false hyper-magnesemic patients. Ion-Mg is characterized by high intra- and inter-individual variabilities particularly in younger women and those with better nutrition. Patients with greater variability could potentially be at risk if exposed to higher concentrations of magnesium in the dialysate. An interventional study, with controlled increase of magnesium concentrations in the dialysate has been planned.

The ILAILL study: iloprost as adjuvant to surgery for acute ischemia of lower limbs: a randomized, placebo-controlled, double-blind study by the italian society for vascular and endovascular surgery.

SUMMARY BACKGROUND DATA: High rate of complications has been reported following revascularization for acute limb ischemia (ALI). No adjuvant pharmacologic treatment, apart from anticoagulation and standard perioperative care, has been shown clinically effective. OBJECTIVE: Aim of this study was to evaluate the effects of the prostacyclin analog iloprost as adjuvant to surgery for ALI. METHODS: A total of 300 patients were randomly assigned to receive perioperative iloprost (intra-arterial, intraoperative bolus of 3000 ng, plus intravenous infusion of 0.5-2.0 ng/kg/min for 6 hours/day for 4-7 days following surgery), or placebo. The primary endpoint was the combined incidence of death and amputation at 3-month follow-up. Secondary endpoints were the incidence of each single major complication, total event rate, symptomatology, and tolerability. RESULTS: The combined incidence of death and amputation was 19.9% in the placebo and 14.1% in the iloprost group (relative risk, 1.56; 95% confidence interval, 0.89-2.75, P = 0.12, Cox regression analysis). A statistically significant lower mortality (4.7%) was reported in patients receiving iloprost, compared with controls (10.6%; relative risk, 2.61; 95% confidence interval, 1.07-6.37, P = 0.03). The overall incidence of fatal plus major cardiovascular events was 33.1% and 22.8% in placebo and iloprost groups, respectively (relative risk, 1.61; 95% confidence interval, 1.04-2.49, P = 0.03). No serious adverse reactions occurred after iloprost administration, nor differences in the incidence of bleeding or hypotension between treatment groups. CONCLUSIONS: Although at lower levels than previously reported, our results confirm the severity of ALI. Iloprost as adjuvant to surgery significantly reduced mortality and overall major event rate. Further data are needed to support this finding, and to face a still open medical issue.

Is it possible to improve outcome in patients undergoing surgery for acute limb ischemia? Can iloprost, a prostacyclin analogue, be helpful?

Acute limb ischaemia (ALI) is a serious medical emergency leading to high rate of complications, being not only limb- but even life-threatening, often in spite of early successful revascularization. Concomitant underlying diseases, the metabolic derangement that seems a result of the acute insult and a possible reperfusion injury following revascularization may account for this severe prognosis. Only anticoagulation, fasciotomy and perioperative supportive treatment are established strategies in ALI patients. Possible benefit from chronic therapies active on vascular and cardiac side has been suggested. Moreover, several categories of compounds, potentially acting on pathophysiological mechanisms of ischemia-reperfusion syndrome, have been tested in experimental models, but none of them has as yet been proven effective in clinical studies. Prostanoids are drugs traditionally utilized in critical chronic limb ischaemia, and their pharmacological properties support a potential usefulness as adjuvant treatment in ALI. In a pilot double-blind placebo-controlled study it has been evaluated the effect of perioperative iloprost, a synthetic prostacyclin analogue, in 30 patients with ALI undergoing Fogarty's thromboembolectomy. The encouraging results of iloprost in this study (lower incidence of major clinical events, more evident metabolic improvement by means of transcutaneous tensiometry--statistically significant reduction in TcpCO2--suggested the opportunity of performing a larger, multicenter trial (ILAILL). In comparison with the pilot study, ILAILL included patients undergoing various types of surgical revascularization, and a longer period of experimental treatment and post-operative follow-up. Preliminary data from this study confirm the high morbidity and mortality of ALI (overall incidence of major events, 29%). Results of ILAILL trial, as for comparison of effects between iloprost and control group, will be available at the beginning of 2005.

Current role of the minimally invasive direct aortic surgery for 3-A repair (MIDAS-3A).

Open aneurysmectomy and aortic graft is still associated with a relatively high morbidity and mortality. To decrease this surgical stress, less invasive procedure, MIDAS-3A technique (Minimally Invasive Direct Aortic Surgery for AAA) was developed, utilizing a 5 cm abdominal incision and a video-laparoscopic assistance (gas-less) to reach the AAA retroperitoneally. From Nov. 1999 to Dec. 2002, 80 patients underwent surgery. This technique provides all the benefits of an open surgical approach, to be combined with the advantages derived from minimized tissue trauma. A comparison between MIDAS-3A and CL (Conventional Laparotomy) was performed, monitorizing-nasogastric drainage;--initial feeding;--pulmonary functions (Vital Capacity, and Forced Expiration Volume);--Intensive Care Unit recovery (long stay);--length of hospital stay;--operative time;--blood loss. The perioperative (30 days) mortality (2.5%), and the morbidity (7.5%) was equal in both groups. No conversion to conventional laparotomy occurred. MIDAS-3A has significantly reduced length of hospital stay (3.5 days), and pulmonary dysfunctions. This technique provides all the benefits of open surgical approach, to be combined with the advantages derived from minimized tissue trauma. MIDAS-3A reduced trauma and pain, which resulted in a shorter hospital stay, and so lower expense and better financial consequences.