Hypertension in primary immunoglobulin A nephropathy (Berger's disease): hemodynamic alterations and mechanisms

Twenty-two patients with primary IgA nephropathy (Berger's disease), 12 with normal and 10 with high blood pressure, were studied. The mean intra-arterial pressure was 88 +/- 6 mm Hg in the normotensive group and 113 +/- 10mm Hg in hypertensive patients; plasma renin activity was high in normotensives and normal in hypertensives. The glomerular filtration rate was 83 +/- 23 and 73 +/- 26 ml/m in 1.73 m2 in normotensive and hypertensive patients, respectively (p = n.s.). Blood volume was high in IgA nephropathy patients: 82 +/- 12 ml/kg body weight in normotensives and 96 +/- 7 ml/kg body weight in hypertensives. Mean arterial pressure was significantly correlated with blood volume (r = 0.541, p less than 0.01), but not with plasma renin activity and glomerular filtration rate. The cardiac index was high in both groups: 4.20 +/- 0.88 liters/min/m2 in normotensive and 3.95 +/- 0.87 liters/min/m2 in hypertensive patients. The total peripheral resistance index was significantly lower than normal in normotensives (1,659 +/- 387 dyn/s/cm-5/m2) and significantly higher (2,419 +/- 562 dyn/s/cm-5 m2) in hypertensives. The cardiac index did not correlate with blood volume and mean arterial pressure; a positive correlation was found between mean arterial pressure and peripheral vascular resistance (r = 0.630, p less than 0.01). No correlation was observed between blood volume and plasma renin activity. Our study indicates that hypertension in IgA nephropathy is primarily volume dependent, and that this increase in blood volume is not related to the deterioration of renal function. The role of the renin-angiotensin system in the maintenance of the hypertension is not well-defined.(ABSTRACT TRUNCATED AT 250 WORDS)     

Myocardial depression characterizes the fatal course of septic shock.

The relationship between cardiac and vascular abnormalities was studied in 68 patients with established septic shock. At time of hemodynamic evaluation, after initial resuscitation, there was no significant difference in arterial pressure, pulmonary artery pressure, cardiac filling pressures, and cardiac index between the 38 survivors of shock and the 30 patients who died of shock, but the left ventricular stroke work index and the right ventricular (RV) stroke work index were higher in survivors than in those who died (mean +/- SD: 25.0 +/- 9.1 vs 20.1 +/- 9.4 gm/m2 [p less than 0.05] and 6.6 +/- 3.6 vs 4.8 +/- 2.8 gm/m2 [p less than 0.05], respectively). Survivors had also higher thermodilution RV ejection fraction and lower RV end-diastolic volumes than had those who died (43.9% +/- 16.3% vs 31.1% +/- 13.7% [p less than 0.01] and 82 +/- 30 vs 99 +/- 31 ml/m2 [p less than 0.05], respectively). Calculated systemic vascular resistance was similar in the two groups, but vasopressors had been required in 22 (58%) of 38 survivors and 25 (83%) of 30 patients who died (p less than 0.01). Moreover, when the patients were separated into two groups according to their cardiac output, higher or lower than 3 L/min/m2, in both subgroups patients who died had lower blood pressure than had survivors. Blood lactate levels were significantly lower in survivors than in nonsurvivors (5.1 +/- 2.1 vs 8.1 +/- 4.7 mEq/L, p less than 0.01). Final data obtained before recovery of shock or death indicated that the survivors had higher arterial pressure, lower pulmonary artery pressure and right atrial pressure, higher stroke volume, and higher RV ejection fraction than had the patients who died. No survivors but all patients who died had been treated with vasopressors. These data therefore indicate that death as a result of septic shock is characterized by both myocardial depression and altered vascular tone and both are probably interrelated.     

Ultrafiltration method for measuring vascular access flow rates during hemodialysis.

BACKGROUND: The vascular access blood flow rate (QA) has been shown to be an important predictor of vascular access failure; therefore, the routine measurement of QA may prove to be a useful clinical method of vascular access assessment. METHODS: We have developed a new ultrafiltration (UF) method for determining QA during HD from changes in arterial hematocrit (H) after abrupt changes in the UF rate with the dialysis blood lines in the normal (DeltaHn) and reverse (DeltaHr) configurations. This method accounts for cardiopulmonary recirculation and requires neither intravenous saline injections nor accurate knowledge of the dialyzer blood flow rate. Clinical studies were conducted in 65 chronic HD patients from three different dialysis programs to compare QA determined by the UF method with that determined by saline dilution using an ultrasound flow sensor. RESULTS: Arterial H increased (P<0.0001) after abrupt increases in the UF rate when the lines were in the normal and reverse configurations. An increase in the UF rate from the minimum setting to 1.8 liter/hr resulted in a DeltaHn of 0.3+/-0.2 (mean +/- SD) H units and a DeltaHr of 1.6+/-1.0 H units. Q(A) values determined by the UF method (1050+/-460 ml/min) were 16+/-25% higher (P<0.001) than those determined by saline dilution (950+/-440 ml/min); the calculated QA values by the UF and saline dilution methods correlated highly with each other (R = 0.92, P<0.0001). The average coefficient of variation for duplicate measurements of QA determined by the UF method in a subset of these patients (N = 21) was approximately 10% when assessed in either the same dialysis session or consecutive sessions. CONCLUSIONS: The results from this study show that changes in arterial H after abrupt changes in the UF rate can be used to assess Q(A).     

Measurement of fiber bundle volume in reprocessed dialyzers

BACKGROUND: Fiber bundle volume (FBV) is an important determinant of dialyzer re-use efficiency. This measurement is performed after the dialyzer has been pressure cleaned and may underestimate the degree of clotted fibers a patient actually encounters while on dialysis. METHODS: Real-time online measure of FBV has been validated using an ultrasound dilution method and the Transonic HD01 monitor (Ithaca, NY, USA). Thirty-one stable chronic hemodialysis patients were studied during the first hour and then during the last 30 minutes of a typical dialysis session. Ultrasound velocity curves using a saline bolus were recorded by flow dilution sensors placed directly on the blood tubing using methods described previously. Blood volume within the dialyzer compartment was determined using a mathematical extrapolation of the measured transit time for a bolus of saline to pass through the dialyzer. These data were compared to FBV obtained using a Seartronics DRS4 (Fresinius, Walnut Creek, CA, USA) reprocessing machine both before and after the same dialysis session. RESULTS: At onset of treatment mean FBV by ultrasound was 100.0 +/- 2.7 ml and was unchanged at the end of the session at 100.0 +/- 3.1 ml (p = 0.49). Before a dialysis session, mean FBV measured on the DRS4 reprocessing machine was 123.5 +/- 2.1 ml and was unchanged following cleaning after dialysis at 121.7 +/- 2.0 ml (p = 0.20). The correlation coefficient between methods was 0.78. CONCLUSIONS: FBV did not change during a dialysis session using an online real-time measure. The results of this study do not support concerns that hemodialysis patients may experience considerably less efficient dialysis than standard FBV determination would suggest due to undetected clotting.     

Brain natriuretic peptide and its relationship to left ventricular hypertrophy in patients on peritoneal dialysis or hemodialysis less than 3 years

An increase of brain natriuretic peptide (BNP) levels is commonly observed in patients on dialysis. Increased circulating levels of BNP are related to future cardiac events and associated with shorter survival in patients on chronic hemodialysis (HD). During the first 1 or 2 years on dialysis, patients on peritoneal dialysis (PD) have been shown to have an improvement in left ventricular hypertrophy, blood pressure, and volume status. This study compares BNP levels and cardiac status of PD and HD patients without cardiovascular disease and on dialysis for less than 36 months. The correlation between plasma BNP concentration and findings of echocardiography before HD scans were examined and compared with findings of PD. Twenty-two HD patients (15 men, 7 women; mean age, 52.5 +/- 13.9 years) and 19 PD patients (10 men, 9 women; mean age, 47.6 +/- 11.3 years) were studied. There were no significant differences between HD and PD patients with regard to age, gender, duration of dialysis, left ventricular mass, left ventricular mass index (p > 0.05). Plasma BNP levels were markedly greater in HD patients (467.8 +/- 466.5 pg/ mL) than those of PD patients (143.1 +/- 165.2 pg/mL). Urine output was significantly higher in PD patients compared with HD patients (p < 0.05). A positive correlation between systolic blood pressure, diastolic blood pressure, and plasma BNP in HD patients (r: 0.653, p: 0.001; r: 0.493, p: 0.023, respectively) was detected. Additional studies are needed to investigate whether lower BNP level in PD patients is an advantage.     

Impact of volume control on left ventricular hypertrophy in dialysis patients

BACKGROUND: Left ventricular hypertrophy (LVH), which strongly predicts cardiac mortality, is seen in more than 60% of end-stage renal disease patients. The aim of this study was to prospectively investigate the effect of salt restriction and strict volume control on blood pressure and LVH. METHOD: Nineteen hypertensive patients on chronic hemodialysis (HD) treatment (age 52 +/- 17 years, 7 women) were included in the study. Treatment consisted of 12-h HD per week, during which as much ultrafiltration (UF) was applied as possible without an excessive blood pressure (BP) drop. Special attention was given to dietary salt restriction. Predialysis mean BP (MBP), body weight (BW), cardio-thoracic index (CTI) and echocardiographic results were recorded at baseline and after 6 and 12 months. RESULTS: All patients reached acceptable BP (< 140/90 mmHg) within three months (10-75 days) with our strict volume control strategy. Mean pre-dialysis BP was 127 +/- 17/78 +/- 9 mm Hg at baseline, 120 +/- 9/75 +/- 6 mm Hg at the 6th month and 118 +/- 11/73 +/- 5 mm Hgat the 12th month. The incidence of symptomatic hypotension gradually decreased from a mean of 22% to 11% and 7%, respectively during follow-up. Left ventricular mass index decreased from 164 +/- 64 to 112 +/- 36 g/m2. CTI, left atrial, left ventricular systolic and diastolic diameters significantly decreased in all patients. Inter-dialytic weight gain was 930 +/- 70 g/day in the follow-up period. Hematocrit did not significantly differ at the first, second and last visits. CONCLUSION: Normal BP and improvement of cardiac structure, in particular a reduction of LVH could be reached in all our patients by intensifying salt restriction and UF.     

Plasma concentrations of immunoreactive-atrial natriuretic polypeptide in patients on hemodialysis

Plasma concentrations of immunoreactive (IR)-atrial natriuretic polypeptide (ANP) were measured before and after hemodialysis (HD) as well as isolated ultrafiltration (UF) in 9 patients with end-stage renal disease. There were significant falls in plasma concentrations of IR-ANP during both UF (from 78.6 +/- 109.7 to 45.4 +/- 56.8 pg/ml; mean +/- SD; p less than 0.025) and HDs (from 84.7 +/- 48.6 to 35.0 +/- 28.4 (p less than 0.01) on first HD; from 73.7 +/- 74.2 to 31.8 +/- 21.8 pg/ml (p less than 0.01) on later HD). There were distinct positive correlations between blood pressures and plasma concentrations of IR-ANP. These results support the view that ANP is secreted mainly by the expansion of blood volume. The fall in plasma concentrations of IR-ANP after HD seems to be caused by the decrease of blood volume, but not by removal due to dialysis of the peptide. However, the physiological role of ANP in patients with end-stage renal disease remains unknown.     

Ventricular pump performance during hypocalcemia: clinical and experimental studies.

We have compared indices of ventricular function during rapid transfusion of citrated (1.5 ml/kg/min) or heparinized (1.5 ml/kg/min) autologous blood in six patients following discontinuation of cardiopulmonary bypass. Infusion of citrated blood was associated with a lowering of plasma ionized calcium concentration ([Ca++], from 0.90 +/- 0.04 to 0.71 +/- 0.4 mM, p less than 0.001) and an increase in pulmonary artery balloon-occluded pressure (PA0, from 9.4 +/- 2.6 to 15.5 +/- 1.7 mm Hg, p less than 0.u1), without a change in left ventricular stroke work index, stroke index, or cardiac index. Transfusion of heparinized blood caused no change in plasma [Ca++]. A rise in PA0, which was similar in magnitude to that observed during citrated blood transfusion, was associated with increased left ventricular stroke work index, stroke index, cardiac index, and mean arterial pressure. Although data obtained during citrated blood transfusion suggest the presence of transient left ventricular dysfunction, its magnitude is not readily expressed in terms of ventricular function curves when accompanied by a simultaneous change in [Cized closed-chest dog by volume loading during hypocalcemia, when mean arterial pressure, heart rate, and [Ca++] were in a steady state, both prior to and following beta blockade with propranolol. Function curves obtained during severe hypocalcemia ([Ca++] = 0.43 +/- 0.02 mM) were shifted significantly to the right and downward, when compared to those obtained during normocalcemia ([Ca++] = 1.06 +/- 0.03 mM). Hypocalcemia combined with beta blockade resulted in severe left ventricular failure, as demonstrated by a flat ventricular function curve.     

No association between deletion-type angiotensin-converting enzyme gene polymorphism and left-ventricular hypertrophy in hemodialysis patients

Left-ventricular hypertrophy (LVH), a bad prognostic sign, is a common finding in hemodialysis patients. The aim of the study was to analyze factors, including angiotensin-converting enzyme (ACE) genotype that may have an effect on the development of LVH in hemodialysis patients. Seventy-nine hemodialysis patients (42 males, 37 females, mean age 37.7 +/- 13.1 years) and 82 age- and sex-matched normotensive healthy controls (40 males, 42 females, mean age 35.6 +/- 5.7 years) were included. Left-ventricular mass index (LVMI) was higher in the hemodialysis group compared to controls (170.1 +/- 69.3 versus 84.9 +/- 15.7 g/m(2), p < 0.001). Fourty-three hypertensive patients in the hemodialysis group had an increased LVMI compared to 36 normotensive hemodialysis patients (194.2 +/- 75.5 versus 141.2 +/- 48.0 g/m(2), p < 0.001). On univariate analysis, LVMI was found to be correlated with blood pressure (r = 0.38, p < 0.001), time spent on dialysis (r = 0.22, p = 0.02) and hemoglobin levels (r = -0.21, p = 0.03). No correlation was found between LVMI and age (r = 0.09, p = 0.22), predialytic creatinine (r = 0.09, p = 0.21) and albumin (r = -0.10, p = 0.18). On multivariate analysis for the predictors of LVMI, blood pressure, time spent on dialysis and hemoglobin levels were also found to be significant. LVMI in DD, ID and II genotypes were 155.0 +/- 71.2, 181.6 +/- 60.6, and 163.6 +/- 83.4 g/m(2), respectively (p > 0.05). No association between LVMI and DD genotype was found. ACE genotype distribution was similar in hemodialysis patients and healthy controls. It was concluded that LVH in hemodialysis patients was mainly related to hypertension, anemia and time spent on dialysis and the DD genotype had no effect on LVMI in hemodialysis patients.     

Hemodynamic effects of calcium chloride injection following cardiopulmonary bypass: response to bolus injection and continuous infusion

To determine the hemodynamic effects of intravenous injection of calcium chloride, 26 patients were studied immediately after termination of extracorporeal circulation. Eighteen patients (Group A) had injection of a single bolus of CaCl2; in the other 8 patients (Group B), the bolus injection was followed by infusion of CaCl2 at a rate of 1.5 mg/kg/min for 10 minutes. Myocardial contractile element velocity (Vpm), aortic blood flow, electrocardiograms, and left ventricular, systemic arterial, pulmonary arterial, and left atrial pressures were recorded continuously. The baseline ionized calcium level after bypass was 3.6 +/- 0.6 mg/100 ml (normal range, 3.9 to 4.5 mg/100 ml); this increased to 5.4 +/- 0.5 mg/100 ml 1 minute after CaCl2 injection. The ionized calcium level was 4.7 +/- 0.6 mg/100 ml 6 minutes after CaCl2 injection in Group A, and was 5.9 +/- 0.2 mg/100 ml and 6.4 +/- 0.2 mg/100 ml at 6 and 10 minutes, respectively, in Group B. There was significant early hemodynamic improvement after CaCl2 injection, including increases in Vpm (p less than 0.001), cardiac index (p less than 0.001), mean blood pressure (p less than 0.01), and stroke volume index (p less than 0.001). A similar pattern of hemodynamic response was observed in both groups. Approximately 1 minute after CaCl2 injection, cardiac index returned to control level, Vpm and mean blood pressure remained elevated, and heart rate declined (p less than 0.01). Systemic vascular resistance gradually increased and was significantly elevated (p less than 0.05) in Group B at 3 minutes and in Group A at 6 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison of nitroglycerin and nitroprusside: I. Treatment of postoperative hypertension

Nitroglycerin improves perfusion to ischemic myocardial regions and therefore has theoretical advantages over sodium nitroprusside to treat hypertension (mean arterial pressure [MAP] greater than 95 mm Hg) following coronary bypass operation. Thirty-three hypertensive patients were randomized to an initial infusion of either nitroglycerin or nitroprusside in a crossover trial designed to reduce MAP to 85 mm Hg. Thermodilution cardiac output measurements permitted calculation of left ventricular stroke work index (LVSWI), and nuclear ventriculograms permitted estimation of left ventricular ejection fraction, left ventricular end-diastolic volume index (LVEDVI), and left ventricular end-systolic volume index (LVESVI). Coronary sinus blood flow was measured by the continuous thermodilution technique, and arterial and coronary sinus lactate measurements permitted calculation of myocardial lactate flux (MVL). Both nitroglycerin and nitroprusside reduced MAP (-25 +/- 12 mm Hg and -20 +/- 10 mm Hg, respectively; not significant [NS]). Nitroglycerin reduced LVSWI more than did nitroprusside (-15 +/- 13 gm-m/m2 and -7 +/- 9 gm-m/m2, respectively; p less than 0.01). Both agents increased left ventricular ejection fraction (nitroglycerin, +8 +/- 8%, and nitroprusside, +10 +/- 7%; NS), and decreased LVEDVI (-20 +/- 22 ml/m2 and -11 +/- 17 ml/m2, respectively; NS) and LVESVI (-13 +/- 14 ml/m2 and -10 +/- 12 ml/m2, respectively; NS). Coronary sinus blood flow decreased with both drugs (NS), but MVL increased with nitroglycerin (+0.02 +/- 0.14 mmol/min) and decreased with nitroprusside (-0.02 +/- 0.02 mmol/min) (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Application of modified ultrafiltration to cardiac surgery in adults]

Modified Ultrafiltration (MUF) was developed for blood concentration and reduction of postoperative edema in cardiac surgery in children. Its beneficial effects on postoperative hemodynamics have been reported. We applied MUF to cardiac surgery in adults and evaluated its usefulness. Between August, 1995 and April, 1997, MUF was performed in 41 adult patients. MUF was carried out immediately after the cessation of cardiopulmonary bypass. The mean fluid volume removed was 1,135.9 +/- 274.1 ml. The patient's haematocrit significantly increased from 23.2 +/- 2.6% to 26.9 +/- 3.2% (p < 0.0001). The dose of inotropes administered was maintained constant during MUF, and no changes were observed in CVP and the heart rate. However, the systolic blood pressure increased from 99.5 +/- 14.7 to 113.2 +/- 16.2 mmHg (p < 0.0001) and cardiac index from 4.2 +/- 0.9 to 4.9 +/- 1.3 l/min/m2 (p = 0.0006). It was suggested that MUF was an useful technique of haemoconcentration and appeared to have beneficial effects on postoperative hemodynamics in adult cardiac surgery.     

Impact of volume status on blood pressure and left ventricle structure in patients undergoing chronic hemodialysis

In this study, we aimed to examine the impact of volume status on blood pressure (BP) and on left ventricular mass index (LVMI) in chronic hemodialysis (HD) patients. This study enrolled 74 patients (F/M: 36/38, mean age 53.5 ± 15.3 years, mean HD time 41.5 ± 41 months) that were on HD treatment for at least 3 months. Demographics, biochemical tests, hemogram and C-reactive protein levels, mean interdialytic weight gain (IDWG), mean percentage of ultrafiltration (UF), and intradialytic complications such as hypotension and cramps were determined. Mean values of predialysis and postdialysis BP measurements were recorded a month before echocardiographic examination. On the day after a midweek dialysis session, 24 h ambulatory BP monitoring (ABPM) and echocardiographic examination were made concurrently. The patients were classified into two groups according to volume status: normovolemic (group 1; 14F/24M, mean age 50 ± 16.7 years, mean dialysis time 47.7 ± 47.7 months) and hypervolemic (group 2; 15F/21M, mean age 57.3 ± 12.7 years, mean dialysis time 34.9 ± 32 months). HD duration, IDWG, UF, and interdialytic complication rates were similar between the two groups (p < 0.05). Eleven patients (28.9%) of group 1 and 8 patients (22.2%) of group 2 showed dipper (p?=?0.50). Valvular damage was more common in group 2 (p?=?0.002). Whereas 33 patients (91.7%) had left ventricular hypertrophy (LVH) in group 2, 21 patients of the group 1 (55.3%) had LVH (p < 0.001). Although LVMI showed a significant positive correlation with cardiothoracic index, predialysis and postdialysis BP, IDWG, UF, daytime and nighttime BP measurements of 24 h ABPM, a significant negative correlation was seen with Kt/V urea and serum albumin levels. In conclusion, increased IDWG and UF and elevated BP are independent predictors of LVH for HD patients. Increased volume status leads to IDWG and elevated BP and eventually causes severe LVMI increases.     

Haemodynamic measurements during controlled hypotension by nitroglycerin (author's transl)

In nine patients undergoing neurosurgical operation for cerebral aneuryms haemodynamic measurements were made before, during and after continuous intravenous administration of Nitroglycerin at a mean dose of 6.5 micrograms/kg . min. Within 15 min of the start of the infusion mean arterial pressure fell from 94.2 +/- 10.5 to 73.4 +/- 11.1 mm Hg. A further decrease of mean arterial pressure even by a substantial raising of the Nitroglycerin dose was not possible. 15 min after the discontinuation of Nitroglycerin administration mean arterial pressure rose to the preinfusion level. The decrease of stroke volume index from 40.8 +/- 9.9 to 31.0 +/- 7.3 ml/m2 was partially compensated by an increase of heart rate from 65.9 +/- 9.6 to 77.7 +/- 19.4 beats/min. Consequently cardiac index fell only slightly from 2.9 +/- 0.6 to 2.5 +/- 0.5 ml/min . m2. The right atrial pressure decreased to 3.3 +/- 2.9 mm Hg, the mean pulmonary arterial pressure to 6.3 +/- 1.9 mm Hg and the pulmonary capillary wedge pressure to 2.3 +/- 2.1 mm Hg. The significant fall of total peripheral resistance to 983 +/- 194 dyn x s/cm5 (p less than 0.05) and the decrease of left ventricular stroke work index to 34.7 +/- 11.5 g . m/m2 contributed to reduce myocardial oxygen consumption. The authors conclude that, because of its effect on blood pressure, it reversibility of action and its absence of adverse side effects Nitroglycerin is a valuable agent for controlled hypotension.     

Increased plasma levels of immunoreactive human atrial natriuretic factor in primary IgA nephropathy

The plasma concentration of the immunoreactive (IR) human atrial natriuretic factor (hANF) was measured in 17 patients with primary IgA nephropathy (IgAN) (9 normotensive and 8 hypertensive subjects without impairment of renal function). Furthermore, correlations with the renin-angiotensin II-aldosterone system and hemodynamic alterations were studied. The mean value of IR-hANF was significantly (p less than 0.002) higher in normotensive IgAN patients (68.2 +/- 14.6 pg/ml) than in controls (48.8 +/- 11.5 pg/ml), while it was slightly and not significantly elevated in hypertensive IgAN patients (58.5 +/- 8.4 pg/ml). In the latter the mean plasma renin activity (PRA) was significantly increased (0.92 +/- 0.30 ng/ml/h; p less than 0.002), while in normotensive IgAN patients (0.68 +/- 0.58 ng/ml/h) no difference was observed. Plasma aldosterone levels showed the same behavior pattern as those of PRA. Hemodynamic studies showed that the mean values of the cardiac index (CI) were significantly (p less than 0.002) high in both normotensive (3.55 +/- 0.5 l/min/m2) and hypertensive (3.32 +/- 0.47 l/min/m2) patients, while a significant reduction in the total peripheral resistance index (TPRI) in normotensive (2171 +/- 349 dyn/s/cm-5/m2; p less than 0.02) and a significant increase in hypertensive (2959 +/- 440 dyn/s/cm-5/m2; p less than 0.05) patients were observed. The mean arterial pressure (MAP) had a positive correlation with the TPRI and an inverse correlation with the IR-hANF.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atrial natriuretic factor after heart operations in children. Relation to hemodynamic and renal parameters.

The purpose of this study was to measure changes in serum atrial natriuretic factor concentrations immediately after heart operations in children under baseline conditions and in response to continuous infusion of dopamine (2.5 and 5.0 micrograms/kg/min). During control periods, levels of atrial natriuretic factor were elevated at 190 +/- 24 and 199 +/- 36 pg/ml. The cardiac index was 2.6 L/min/m2 and the renal plasma flow was decreased to 269 +/- 41 ml/min/1.73 m2, indicating a state of renal vasoconstriction (mean renal fraction of cardiac index of 10.0% +/- 1.0%). The mean sodium fractional reabsorption was 99.0% +/- 0.2%. During dopamine infusion, atrial natriuretic factor concentrations increased to 259 +/- 57 pg/ml and to 280 +/- 56 pg/ml, with dopamine 2.5 and 5.0 micrograms/kg/min, respectively (p = not significant), whereas left atrial pressure decreased from 11.7 +/- 0.9 mm Hg during the control period to 10.1 +/- 0.9 and to 9.9 +/- 1.0 mm Hg (p less than 0.05). No correlation was found between changes in left atrial pressure and atrial natriuretic factor levels. Dopamine at 5 micrograms/kg/min increased the cardiac index to 3.0 +/- 0.2 L/min/m2 (p less than 0.001) and the renal plasma flow to 406 +/- 61 ml/min 1.73 m2 (p less than 0.001), alleviating the renal vasoconstriction. The mean urinary sodium excretion increased to 0.33 +/- 0.08 mmol/kg/hr (p less than 0.01). The atrial natriuretic factor plasma concentrations were not related to the urinary sodium excretion, renal plasma flow, or glomerular filtration rate during the control period or during dopamine treatment. These data indicate that after heart operations in children, low urinary sodium excretion occurs despite high circulating atrial natriuretic factor levels. Atrial natriuretic factor concentrations were related neither to left atrial pressures nor to the renal changes induced by dopamine.     

Hemodynamic effects of DBcAMP in patients with low cardiac output syndrome following open-heart surgery

Hemodynamic effects of DBcAMP given at 0.05 to 0.3 mg/kg/min for 30 minutes to patients with low cardiac output less than 2.21/min/m2, to patients on IABP and on dopamine or dobutamine were investigated after open-heart surgery. Hemodynamic improvements were observed in cardiac index from 1.81 +/- 0.3 (mean +/- SD) to 2.56 +/- 0.401/min/m2 (p less than 0.001), stroke index from 20.5 +/- 5.2 to 26.4 +/- 5.2 ml/best/m2 (p less than 0.001). TRP decreased from 1963.8 +/- 682.8 to 1153.9 +/- 449.0 (p less than 0.001). These changes were similar to those of Groups II (3.0 greater than or equal to C1 greater than or equal to 2.21/min/m2) and of Group III (C1 greater than 3.01/min/m2). Increases were also observed in CI from 2.28 +/- 0.67 to 2.96 +/- 0.671/min/m2 (p less than 0.001) and in stroke index from 24.4 +/- 7.2 to 29.5 +/- 6.4 ml/best/m2 (p less than 0.001) and significant decreases were observed in TPR and PVR in patients receiving dopamine or dobutamine. These results strongly suggest the inotropic action of DBcAMP was independent on the beta receptor activity and could be a powerful adjunct in the treatment of low cardiac output patients on whom the dopamine or dobutamine was ineffective.     

Association between high ultrafiltration rates and mortality in uraemic patients on regular haemodialysis. A 5-year prospective observational multicentre study.

BACKGROUND: High ultrafiltration rate on haemodialysis (HD) stresses the cardiovascular system and could have a negative effect on survival. METHODS: The effect of ultrafiltration rate (UFR; ml/h/kg BW) on mortality was prospectively evaluated in a cohort of 287 prevalent uraemic patients in regular HD from 1 January 2000 to 31 December 2005. Patients: 165 men and 122 women, age 66 +/- 13 years, on regular HD for at least 6 months, median: 48 months (range 6-372 months). Mean UFR was 12.7 +/- 3.5 ml/h/kg BW, Kt/V: 1.27 +/- 0.13, body weight (BW): 62 +/- 13 kg, PCRn: 1.11 +/- 0.20 g/kg/day, duration of dialysis: median 240 min (range 180-300 min), mean arterial blood pressure (MAP) 99 +/- 9 mm/Hg. One hundred and forty nine patients (52%) died, mainly for cardiovascular reasons (69%). Multivariate Cox regression analysis was utilized to evaluate the effect on mortality of UFR, age, sex, dialytic vintage, cardiovascular disease (CVD), diabetes, dialysis modality, duration of HD, BW, interdialytic weight gain (IWG), body mass index (BMI), MAP, pulse pressure (PP), Kt/V, PCRn. RESULTS: Age (HR 1.06; CI 1.04-1.08; P < 0.0001), PCRn (HR 0.17, CI 0.07-0.43; P < 0.0001), diabetes (HR 1.81, CI 1.24-2.47; P = 0.007), CVD (HR 1.86; CI 1.32-2.62; P = 0.007) and UFR (HR 1.22; CI 1.16-1.28; P < 0.0001) were identified as factors independently correlated to survival. We estimated the discrimination potential of UFR, evaluated at baseline, in predicting death at 5 years, calculating the relative receiver operating characteristic (ROC) curves and the cut-off that minimizes the absolute difference between sensitivity and specificity. CONCLUSIONS: High UFRs are independently associated with increased mortality risk in HD patients. Better survival was observed with UFR < 12.37 ml/h/kg BW. For patients with higher UFRs, longer or more frequent dialysis sessions should be considered in order to prevent the deleterious consequences of excessive UFR.     

Change from conventional haemodiafiltration to on-line haemodiafiltration.

BACKGROUND: On-line haemodiafiltration (HDF) is a technique which combines diffusion with elevated convection and uses pyrogen-free dialysate as a replacement fluid. The purpose of this study was to evaluate the difference between conventional HDF (1-3 l/h) and on-line HDF (6-12 l/h). METHODS: The study included 37 patients, 25 males and 12 females. The mean age was 56.5 +/- 13 years and duration of dialysis was 62.7 +/- 49 months. Three patients dropped out for transplantation, three patients died and three failed to complete the study period. Initially all patients were on conventional HDF with high-flux membranes over the preceding 34 +/- 32 months. Treatment was performed with blood flow (QB) 402 +/- 41 ml/min, dialysis time (Td) 187 min, dialysate flow (QD) 654 +/- 126 ml/min and replacement fluid (Qi) 4.0 +/- 2 l/session. Patients were changed to on-line HDF with the same filtre and dialysis time, QD 679 +/- 38 ml/min (NS), QB 434 +/- 68 ml/min (P < 0.05) and post-dilutional replacement fluid 22.5 +/- 4.3 l/session (P < 0.001). We compared conventional HDF with on-line HDF over a period of 1 year. Dialysis adequacy was monitored according to standard clinical and biochemical criteria. Kinetic analysis of urea and beta2-micro-globulin (beta2m) was performed monthly. RESULTS: Tolerance was excellent and no pyrogenic reactions were observed. Pre-dialysis sodium increased 2 mEq/l during on-line HDF. Plasma potassium, pre- and post-dialysis bicarbonate, uric acid, phosphate, calcium, iPTH, albumin, total proteins, cholesterol and triglycerides remained stable. The mean plasma beta2m reduction ratio increased from 56.1 +/- 8.7% in conventional HDF to 71.1 +/- 9.1% in on-line HDF (P < 0.001). The pre-dialysis plasma beta2m decreased from 27.4 +/- 8.1 to 24.2 +/- 6.5 mg/l (P < 0.01). Mean Kt/V (Daugirdas 2nd generation) was 1.35 +/- 0.21 in conventional HDF compared with 1.56 +/- 0.29 in on-line HDF (P < 0.01), Kt/Vr (Kt/V taking into consideration post-dialysis urea rebound) 1.12 +/- 0.17 vs 1.26 +/- 0.20 (P < 0.01), BUN time average concentration (TAC) 44.4 +/- 9 vs 40.6 +/- 10 mg/dl (P < 0.05) and protein catabolic rate (PCR) 1.13 +/- 0.22 vs 1.13 +/- 0.24 g/kg (NS). There was a significant increase in haemoglobin (10.66 +/- 1.1 vs 11.4 +/- 1.5) and haematocrit (32.2 +/- 2.9 vs 34.0 +/- 4.4%), P < 0.05, during the on-line HDF period, which allowed a decrease in the erythropoietin doses (3861 +/- 2446 vs 3232 +/- 2492 UI/week), (P < 0.05). Better blood pressure control (MAP 103.8 +/- 15 vs 97.8 +/- 11 mmHg, P < 0.01) and a lower percentage of patients requiring antihypertensive drugs were also observed. CONCLUSION: The change from conventional HDF to on-line HDF results in increased convective removal and fluid replacement (18 l/session). During on-line HDF treatment, dialysis dose was increased for both small and large molecules with a decrease in uraemic toxicity level (TAC). On-line HDF provided a better correction of anaemia with lower dosages of erythropoietin. Finally, blood pressure was easily controlled.