Pulmonary Hypertension and Right Heart Failure in Chronic Kidney Disease: New Challenge for 21st-Century Cardionephrologists.

Pulmonary hypertension is defined as an increased systolic pulmonary pressure of >30 mm Hg, and it shows a 40% prevalence in hemodialysis patients due to vascular access (both central venous catheter and arteriovenous fistula). Secondary pulmonary hypertension in chronic kidney disease patients is strictly related to pulmonary circulation impairment together with chronic volume overload and increased levels of cytokines and growth factors, such as FGF, PDGF, and TGF-ß, leading to fibrosis. Endothelial dysfunction, together with lower activation of NOS, increased levels of serum endothelin and fibrin storages, involves an extensive growth of endothelial cells leading to complete obliteration of pulmonary vessels. Pulmonary hypertension has no pathognomonic and distinctive symptoms and signs; standard transthoracic echocardiography allows easy assessment of compliance of the right heart chambers. The therapeutic approach is based on traditional drugs such as digitalis-derived drugs, vasodilatory agents (calcium channel blockers), and oral anticoagulants. New pharmacological agents are under investigation, such as prostaglandin analogues, endothelin receptor blockers, and phosphodiesterase-5 inhibitors.

[Comparison among ecography, scintigraphy and surgery in the localization of parathyroid glands in uremic patients undergoing parathyroidectomy]. / Confronto tra ecografia, scintigrafia e chirurgia nella localiz- zazione delle ghiandole paratiroidi nei pazienti uremici in dialisi sottoposti a paratiroidectomia.

BACKGROUND: Sensitivity and specificity of the most widely employed techniques of parathyroid glands localization, namely echography and scintigraphy, are mostly obtained with short-term follow-up data and do not underline the existence of a methodological problem. As a matter of fact, both methods identify only pathological glands, with no "normal" results; therefore "true negatives" cannot be obtained. Aim of our study was to compare, by means of a statistically appropriate approach, the results of echography, scintigraphy and surgery with the data obtained after a mid term follow-up period, enabling us to discover all parathyroid glands. METHODS: Twenty six consecutive dialysis patients (14M/12F; age 50+/-12 years) underwent echography and scintigraphy immediately before a total parathyroidectomy with autotransplantation and were followed-up for 6 months to recognize all the existing glands (PTH levels and scintigraphy). RESULTS: Total identified glands were: 73 by scintigraphy, 86 by echography, 99 by surgery and 103 by follow-up data. The concordance indexes (K0) between the number of glands effectively present in the individual patient (follow-up data) and those identified with each method were rather low with scintigraphy (0.071) and echography (0.218), and acceptable (0.578) with surgery. The number of patients correctly classified was: 9/26 (34,6%) with scintigraphy, 13/26 (50%) with echography and 22/26 (85%) with surgery. Finally, the number of wrongly identified glands (from zero to three) in each patient was similar with scintigraphy (65,4%) and echography (50%) and significantly better with surgery (15,6%; p<0.01). CONCLUSIONS: The most reliable technique to identify parathyroid glands in uremic subjects is surgery, nonetheless a meticulous clinical follow-up is necessary to recognize all of them.

Utilization of guidelines for the management of hypertension in cardiovascular risk scoring of renal patients.

BACKGROUND: Recent guidelines for the management of hypertension by the European Societies of Hypertension and Cardiology (ESH-ESC), consider, besides normal and normal high blood pressure, also early renal failure as a significant factor scoring the individual cardiovascular (CV) risk in each patient. Considering that the nephrologists have not yet adopted a similar system to score CV risk in renal failure, we believed reasonable to evaluate whether the ESH-ESC guidelines were applicable to renal patients and to what extent useful to estimate the CV risk in chronic renal disease. PATIENTS AND METHODS: According to the above-mentioned guidelines, CV risk score was evaluated in 386 ambulatory patients (212 M/174 F; aged 53 +/- 15 years) with the following clinical diagnosis: hypertension (n=48), lithiasis (n=49), chronic renal failure (n=182), transplantation (n=61) and dialysis (n=46). RESULTS: We obtained a "no score" group and five progressive risk classes graded from 1 to 5. Infact thirthyfour cases were not scored because of "optimal" blood pressure control, whilst the remaining 352 averaged a score of 3.9 +/- 1.1 ("high" CV risk condition). In these, all the scores were present and the distribution of cases evidenced a prevailing of score 4 and 5 in chronic renal failure (19 and 52% of the cases, respectively) and in transplantation (26% and 39%), but not in hypertension and lithiasis. In dialysis, only score 4 and 5 (35% and 59% respectively) occurred, while 4 cases (6%) were not scored due to "optimal" blood pressure values. Target organ damage, acquired clinical conditions, modifiable and non-modifiable risk factors had all a positive correlation with the risk score. CONCLUSIONS: Our study suggests that ESH-ESC guidelines for the management of hypertension can be used to obtain a global CV risk score also in chronic kidney diseases, with the exception of dialysis. In chronic renal failure, the risk of underestimating the real incidence of future CV events might be overcome, at least partially, by the possibility of highlighting in individual patients the concomitance of risk factors requiring a very early preventive and aggressive therapy.

D-Lactic acidosis in calves as a consequence of experimentally induced ruminal acidosis.

In order to test the hypothesis that ruminal drinking in calves can lead to D-lactic metabolic acidosis, ruminal acidosis was induced in nine calves by intraruminal application of untreated whole milk via a stomach tube. The amount of the daily force-fed liquid was 3 x 1 l. The experimental design called for an end of intraruminal applications if two or more of the following signs were observed: severe depression, estimated degree of dehydration >10%, absence of sucking reflex, lack of appetite for two consecutive feedings, severe metabolic acidosis with calculated Actual Base Excess (ABE) <-15 mmol/l. The procedure was scheduled to be discontinued on the 17th day of experiment. The onset of ruminal acidification occurred rapidly, and mean pH value fell from 6.70 (+/-0.48) to 4.90 (+/-0.38) after the first application. The following days the pH values varied between 4 and 5. Rumen acidity was characterized biochemically by a significant increase in both isomers of lactic acid. The effects of the intraruminal administration on the calves were detrimental; eight of nine calves showed an acute disease process. According to the pre-established clinical standard, seven of nine calves were removed from the intraruminal feeding schedule. All but one of the calves developed severe systemic acidosis. The increase in anion gap demonstrated the net acid load. In all the calves D-lactate levels were found to show a significant and rapid increase. On the contrary, L-lactate never deviated from physiological levels. These observations confirm that, in young calves as in adult cattle, ruminal acidosis may lead to a clinically manifested D-lactic metabolic acidosis.