Acute effect of a peritoneal dialysis exchange on electrolyte concentration and QT interval in uraemic patients.

BACKGROUND: Hemodialysis (HD) sessions induce changes in plasma electrolytes that lead to modifications of QT interval, virtually associated with dangerous arrhythmias. It is not known whether such a phenomenon occurs even during peritoneal dialysis (PD). The aim of the study is to analyze the relationship between dialysate and plasma electrolyte modifications and QT interval during a PD exchange. METHODS: In 15 patients, two manual PD 4-h exchanges were performed, using two isotonic solutions with different calcium concentration (Ca++1.25 and Ca1.75++ mmol/L). Dialysate and plasma electrolyte concentration and QT interval (ECG Holter recording) were monitored hourly. A computational model simulating the ventricular action potential during the exchange was also performed. RESULTS: Dialysis exchange induced a significant plasma alkalizing effect (p < 0.001). Plasma K+ significantly decreased at the third hour (p < 0.05). Plasma Na+ significantly decreased (p < 0.001), while plasma Ca++ slightly increased only when using the Ca 1.75++ mmol/L solution (p < 0.01). The PD exchange did not induce modifications of clinical relevance in the QT interval, while a significant decrease in heart rate (p < 0.001) was observed. The changes in plasma K+ values were significantly inversely correlated to QT interval modifications (p < 0.001), indicating that even small decreases of K+ were consistently paralleled by small QT prolongations. These results were perfectly confirmed by the computational model. CONCLUSIONS: The PD exchange guarantees a greater cardiac electrical stability compared to the HD session and should be preferred in patients with a higher arrhythmic risk. Moreover, our study shows that ventricular repolarization is extremely sensitive to plasma K+ changes, also in normal range.

[Sodium balance and peritoneal ultrafiltration in refractory heart failure].

About 5% of patients with heart failure (HF) reach the end-stage of disease, becoming refractory to therapy. The clinical course of end-stage HF is characterized by repeated hospitalizations, severe symptoms, and poor quality of life. Peritoneal ultrafiltration (PUF), removing water and sodium (Na+), can benefit patients with end-stage HF. However, effects on fluid and electrolyte removal have not been fully characterized. In this pilot study in patients with chronic HF and moderate chronic renal failure, we evaluated the effects of water and sodium removal through PUF on ventricular remodeling, re-hospitalization, and quality of life. Patients with end-stage HF (NYHA class IV, ≥3 HF hospitalization/year despite optimal therapy), not eligible for heart transplantation underwent peritoneal catheter positioning and began a single-day exchange with icodextrin at night (n=6), or 1-2 daily exchanges with hypertonic solution (3.86%) for 2 hours with 1.5-2 L fill volume (n=3). At baseline, average ultrafiltration was 500±200 ml with icodextrin, and 700±100 ml with hypertonic solution. Peritoneal excretion of Na+ was greater with icodextrin (68±4 mEq/exchange) compared to hypertonic solution (45±19 mEq/exchange). After a median 12-month follow-up, rehospitalizations decreased, while NYHA class and quality of life (by Minnesota Living with HF questionnaire), improved. In end-stage HF patients, PUF reduced re-hospitalization and improved quality of life. It can be an additional treatment to control volume and sodium balance.

Spondylodiscitis in hemodialysis patients: a new emerging disease? Data from an Italian Center.

Hemodialysis (HD) patients are at high risk for infectious complications such as spondylodiscitis. The aim of this retrospective study was to evaluate the cases of infective spondylodiscitis occurred between May 2005 and October 2019 among HD patients at our center. In 14 years, there were 9 cases (mean age 69±12 years). The main comorbidities found were diabetes mellitus (55.6% of patients), hypertension (55.6%), bone diseases (22.2%), cancer (11.1%) and rheumatoid arthritis treated with steroids (11.1%). The clinical onset included back pain (100% of cases), fever (55.6%), neurological deficits (33.4%), leukocytosis (55.6%) and elevated CRP level (88.9%). Most cases were diagnosed by magnetic resonance imaging (66.7%) with more frequent involvement of lumbar region (77.8%). Blood cultures were positive in five patients (mostly for S. aureus); three of them used catheters as vascular access and, in two cases, their removal was necessary. The mean time interval between the onset of symptoms and the diagnosis was 34±42 days. All patients received antibiotic treatment for a mean duration of 6 weeks; most cases were initially treated with vancomycin or teicoplanin plus ciprofloxacin. Most patients (77.8%) recovered after a mean of 3.5 months; one patient had a relapse after 2 years and one patient had long-term neurologic sequelae. Infective spondylodiscitis in HD must be suspected in the presence of back pain, even in the absence of fever or traditional risk factors. An early diagnosis could improve the outcome. Close monitoring of vascular access, disinfection procedures and aseptic techniques are important to avoid this complication.

Case report: the thoracoscopic surgery in peritoneal-pleural leakage. A valid therapeutic strategy.

Pleuro-peritoneal leakage is an uncommon complication of peritoneal dialysis (PD). In this study, we report the case of a male patient (age 83), treated with PD (daytime single-exchange). In October 2019, hospitalization was necessary due to dyspnoea and a reduction of peritoneal ultrafiltration. A right pleural leakage resulted at chest x-ray. A regression of the pleural leakage was immediately observed after interrupting PD. It was then performed a pleuro-peritoneal CT scan at baseline, followed by a second scan performed 4 hours after the injection of 2 L of isotonic solution with 100ml of contrast medium, which evidenced a pleuro-peritoneal communication. It was then decided to perform a video-assisted thoracoscopic surgery (VATS), that showed no evidence of diaphragm communication. It was then executed a pleurodesis using sterile talcum. The patient was released on the 3rd day, with a conservative therapy and a low-protein diet. After 2 weeks a new pleuro-peritoneal CT scan with contrast medium was executed. This time the scan evidenced the absence of contrast medium in the thoracic cavity. The patient then resumed PD therapy, with 3 daily exchanges with isotonic solution (volume 1.5 L), showing no complications. Concerning the treatment of pleuro-peritoneal leakage, VATS allows both the patch-repairing of diaphragmatic flaws and the instillation of chemical agents. In our case, VATS allowed the chemical pleurodesis which in turn enabled, in just 2 weeks of conservative treatment, the resuming of PD. In conclusion, this methodology is a valid option in the treatment of pleuro-peritoneal leakage in PD patients.

Association between aldosterone synthase (CYP11B2) polymorphism and left ventricular mass in human essential hypertension.

OBJECTIVES: The aim of our study was to evaluate the relationship between aldosterone synthase gene polymorphism and cardiac dimensions in essential hypertension. BACKGROUND: Higher aldosterone synthase messenger ribonucleic acid levels in the human heart are accompanied by increased intracardiac aldosterone production, a phenomenon that is associated with cardiac fibrosis and hypertrophy. Recent evidence suggests that a polymorphism (-344C/T) in the promoter region of the aldosterone synthase gene is associated with increased constitutive aldosterone production. METHOD: Relationships between M-mode echocardiographic cardiac dimensions and aldosterone synthase -344C/T polymorphism were studied in 210 never-treated, middle-aged patients (age 41.6 +/- 1.4 years) affected by mild to moderate essential hypertension. Among these patients, 48 had the genotype -C344C, 97 had -C344T, and 65 had -T344T. Patients in the three groups were similar in terms of age, gender, body mass index, and blood pressure. RESULTS: Left ventricular (LV) mass and thickness were positively correlated with the number of T alleles: LV mass (CC, CT, and TT, respectively: 168 +/- 6.9, 179 +/- 5.2, and 193 +/- 6.9 g; p = 0.03), LV septal thickness (0.99 +/- 0.02, 1.03 +/- 0.02, and 11.08 +/- 0.03 cm, p = 0.04), PWT (0.93 +/- 0.03, 0.95 +/- 0.01, and 1.03 +/- 0.02 cm; p = 0.002), and relative wall thickness (38.3 +/- 1.2%, 38.8 +/- 0.8%, and 42.8 +/- 1.1%; p = 0.004). This trend was confirmed by linear regression, suggesting a "major gene" behavior for the T allele. Multiple regression analysis showed that this effect was independent of anthropometric and clinical factors, including adrenal aldosterone. CONCLUSIONS: Our data suggest that -344C/T polymorphism affects LV mass and thickness in essential hypertension, independent of adrenal aldosterone. A role for intracardiac aldosterone synthesis is hypothesized.

Haplotype analysis of carnitine transporters and left ventricular mass in human essential hypertension.

OBJECTIVE: The carnitine-associated alteration of myocardial fatty acid metabolism may be one of the molecular mechanisms underlying left ventricular hypertrophy (LVH) in essential hypertension. We tested the hypothesis that polymorphisms of the genes involved in carnitine transport, OCTN2, CPT1A, CPT1B, and CPT2, might be associated with LVH. DESIGN: Haplotype-based association analysis in an observational study. SETTING: Outpatients from the Nephrology Division of the University Hospital. PATIENTS: A total of 215 never-treated, middle-aged patients with mild essential hypertension. METHODS: Relationships between left ventricular mass index (LVMI) (measured with m-mode echocardiography) and haplotype combinations for 13 common genetic variants selected from single nucleotide polymorphism database (dbSNPs). RESULTS: The SNPs were selected to cover the genomic region of the four loci, and a total of 23 haplotypes were identified: 8 for OCTN2 (H1 to H8), 8 for CPT1A (H9 to H16), 3 for CPT1B (H17 to H19), and 4 for CPT2 (H20 to H23). In a multilocus haplotype analysis, after adjusting for sex, age, systolic blood pressure, diastolic blood pressure, body mass index, and duration of hypertension, a significant effect on LVMI was seen for H13 (+8.9, P = .05), H14 (-5.63, P = .05), H15 (-18.79, P = .0006), H18 (-1.66, P = .03), and H22 (-3.42, P = .004). These significant haplotypes were respectively 3.7%, 1.6%, 1.6%, 39.3%, and 29.7% of the total population. CONCLUSIONS: These results identify the carnitine-transporter gene family as candidate modifiers of LVMI in human hypertension. The use of common SNPs to define informative haplotypes associated with the phenotype of interest is the starting point for progress toward identification of the trapped contributing SNP(s).

Home peritoneal ultrafiltration in patients with severe congestive heart failure without end-stage renal disease.

Congestive heart failure (CHF), mainly because of ischemic heart disease, is becoming a common medical problem. As CHF worsens and reaches New York Heart Association (NYHA) class IV, many patients can become refractory to medical therapy, especially those who are elderly or who have pre-existing non uremic chronic renal failure. For such patients, quality of life, morbidity, and mortality are expected to be bad. Our objective in the present study was to make a preliminary assessment of the usefulness of icodextrin administered in a single nocturnal peritoneal exchange to patients nonrespondent to the maximal conventional medical therapy. We studied two patients (aged 80 and 87 years), who were affected by severe dilatative cardiomyopathy and moderate-to-severe chronic renal failure. After at least 12 months of treatment, we observed a significant improvement in quality of life and a reduction in morbidity and hospitalization in both patients. Both patients also significantly increased their creatinine clearance. One patient maintained ejection fraction stability (22%-->27%); the other experienced an increase in ejection fraction to 50%from 25%. These preliminary observations suggest that a single nocturnal exchange with icodextrin can be an effective treatment in patients affected by refractory CHF and moderate-to-severe chronic renal failure.

Association of atrial natriuretic peptide and type a natriuretic peptide receptor gene polymorphisms with left ventricular mass in human essential hypertension.

OBJECTIVES: The goal of our study was to investigate the relationships between atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and type A natriuretic peptide receptor (NPRA) gene polymorphisms and left ventricular structure in human essential hypertension. BACKGROUND: Experimental evidence supports a key role for natriuretic peptides in the modulation of cardiac mass. This relationship has not yet been described in human disease. METHODS: A total of 203 hypertensive patients were studied by mono-bidimensional echocardiography. Three markers of the ANP gene (-C664G, G1837A, and T2238C polymorphisms) and a microsatellite marker of both NPRA and BNP genes were characterized. RESULTS: Patients carrying the ANP gene promoter allelic variant had increased left ventricular mass index (117.4 +/- 1.7 g vs. 95.7 +/- 1.7 g, p = 0.005), left ventricular posterior wall thickness (1.14 +/- 0.07 cm vs. 0.96 +/- 0.01 cm, p < 0.0001), left ventricular septal thickness (1.12 +/- 0.10 cm vs. 1.04 +/- 0.01 cm, p = 0.01), and relative wall thickening (47.5 +/- 4.1% vs. 39.4 +/- 5.3%, p = 0.001) as compared with the wild-type genotype. These associations were independent from anthropometric factors and major clinical features and were confirmed in a large subgroup of never-treated hypertensive patients (n = 148). Carrier status of the ANP gene promoter allelic variant was associated with significantly lower plasma proANP levels: 1,395 +/- 104 fmol/ml versus 3,110 +/- 141 fmol/ml in hypertensive patients carrying the wild-type genotype (p < 0.05). A significant association for NPRA gene variants with left ventricular mass index and left ventricular septal thickness was found. The analysis of BNP did not reveal any effect on cardiac phenotypes. CONCLUSIONS: Our findings show that the ANP/NPRA system significantly contributes to ventricular remodeling in human essential hypertension.