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Biomedical subjects

V Wizemann

Publications and source records attributed to V Wizemann.

At least 37 records · Page 2Linked to original sources
PubMed1993

Effects of acetate on left ventricular function in hemodialysis patients.

Two approaches were chosen to assess the controversially debated influence of acetate on the heart in dialysis patients: (1) To separate acetate effects from influences of dialysis, acetate was infused in 12 chronic dialysis patients with normal systolic function on a dialysis-free day, and left ventricular (LV) function was assessed by LV pressure/volume loops. Hyperacetatemia (3-5 mmol/l) resulted in a decrease in LV preload (LV end-diastolic pressure decreased from 16 +/- 3 to 10 +/- 4 mm Hg, p < 0.01) but had no influence on LV contractility. (2) In 8 dialysis patients without cardiac disease, isovolemic acetate or bicarbonate dialysis was performed. During both procedures, there were comparable changes in serum electrolytes as well as in echocardiographic parameters. LV contractility measured by velocity of circumferential fiber shortening increased during acetate and bicarbonate dialysis (1.47 +/- 0.22 to 1.77 +/- 0.29, p < 0.01; 1.47 +/- 0.21 to 1.70 +/- 0.22 circ/s, p < 0.01). It is concluded that mild hyperacetatemia does not influence LV contractility and that dialysis-induced changes in serum electrolytes are responsible for the increase in LV contractility during dialysis. However, the pronounced acetate effect on LV preload implies considerable therapeutic implications.

Acetates↗
PubMed1993

Follow-up of cardiac changes induced by anemia compensation in normotensive hemodialysis patients with left-ventricular hypertrophy.

28 anemic [hematocrit (Hct) < 25%] and normotensive patients on maintenance hemodialysis with uremia-associated left-ventricular (LV) hypertrophy were treated with recombinant human erythropoietin. Before correction of anemia, after 4 months at a target Hct of 35% and 16 months (Hct still 35%) patients were assessed by echocardiography and physical stress testing. Partial correction of anemia resulted in a decrease in the LV end-diastolic diameter from 52.6 +/- 3.4 SD mm to 49.6 +/- 3.4 mm at 4 months (p < 0.01) and 47.9 +/- 2.9 mm at 16 months (p < 0.001). Concomitantly there was a slight decrease of LV end-systolic diameter (30.4 +/- 3.1 vs. 32.6 +/- 3.5 mm, p < 0.05) and LV posterior wall thickness (12.1 +/- 0.9 vs. 12.8 +/- 0.8 mm, p < 0.05) at 16 months. The calculated LV muscle mass index was reduced from 199 +/- 35 g/m2 to 173 +/- 34 g/m2 at 4 months (p < 0.01) and 160 +/- 28 g/m2 at 16 months (p < 0.001). Heart rate at rest was reduced significantly from 80 +/- 12 to 73 +/- 11 min (p < 0.01) at 4 and 16 months. LV ejection fraction, thickness of LV septum and blood pressure did not change. Partial correction of anemia led to an increase of maximal physical stress tolerance from 1.4 +/- 0.4 to 1.85 +/- 0.5 W/kg b.w. at 4 months (p < 0.01), which was maintained at 16 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Options in dialysis therapy: significance of cardiovascular findings.

Most patients receiving renal replacement therapy have cardiovascular disease. The most frequent conditions are left ventricular hypertrophy and coronary artery disease. Hemodialysis is associated with a characteristic spectrum of acute complications (such as hypotension, sudden death) that can be explained by typical dialysis-induced effects on the heart. With continuous ambulatory peritoneal dialysis (CAPD) some of those cardiovascular complications are ameliorated due to slow ultra-filtration and absence of an arteriovenous fistula. It is concluded that CAPD might be the preferable option in patients with cardiovascular disease when hemodialysis can only be performed in a standardized and often aggressive manner. However, achievement of medically-defined goals appears to be more important than technique in dialysis therapy.

Cardiovascular Diseases↗
PubMed1992

Effect of erythropoietin on ischemia tolerance in anemic hemodialysis patients with confirmed coronary artery disease.

From a total of 81 patients on maintenance hemodialysis who underwent coronary angiography, 8 patients fulfilled the criteria: significant coronary artery disease, hematocrit less than 27%, reproducible (ECG) positive treadmill test, no disturbance of repolarization in ECG at rest. Exercise stress testing was performed at a hematocrit of 25 +/- 2% and following erythropoietin therapy at a hematocrit of 34 +/- 0.5%. Symptom-limited exercise performance increased in all patients (1.10 +/- 0.3 W/kg b.w. vs. 1.44 +/- 0.31 W/kg b.w., p less than 0.01) as well as exercise duration (489 vs. 362 s, p +/- 0.01). ST segment depression during maximal exercise was reduced from a mean of 2.1 to 0.4 mm (p less than 0.01). It is concluded that amelioration of renal anemia by erythropoietin in dialysis patients with significant coronary artery disease reduces exercise-induced myocardial ischemia.

Adult↗
PubMed1991

Catecholamines and thrombocyte alpha 2-adrenoceptors in patients with acute myocardial infarction.

In 28 patients with first myocardial infarction plasma catecholamines and thrombocyte alpha 2-adrenoceptors were studied. The first determination (by HPLC and radioligand binding, respectively) was performed immediately after hospital admission and 6 weeks later. In the acute phase of myocardial infarction plasma adrenaline and noradrenaline levels were high. No significant differences in thrombocyte alpha 2-adrenoceptors and plasma concentrations of adrenaline and noradrenaline were observed between diabetic and non-diabetic patients. In three non-surviving patients only the affinity of the alpha 2-adrenoceptor to the radioligand was decreased (P less than 0.05), the relatively high catecholamine levels failed to reach statistical significance. Six weeks after hospital admission, adrenaline plasma levels were significantly decreased in diabetic and non-diabetic patients, while noradrenaline was only lowered in non-diabetic patients (P less than 0.05). Only in this group did the receptor number (BMAX) show a significant elevation 6 weeks after hospital admission. We conclude that, in acute myocardial infarction, alpha 2-adrenoceptors mainly interact with noradrenaline. Accordingly, no adrenoceptor alteration occurred in diabetic patients, who showed only a decrease in adrenaline but not in noradrenaline plasma concentrations 6 weeks following myocardial infarction. The different patterns in diabetic and non-diabetic patients suggest an alteration of catecholamine metabolism in diabetes mellitus.

Blood Platelets↗
PubMed1991

Abnormal diastolic left ventricular filling by pulsed Doppler echocardiography in patients on continuous ambulatory peritoneal dialysis.

To determine characteristics of diastolic left ventricular (LV) function in patients on continuous ambulatory peritoneal dialysis (CAPD), two groups of CAPD patients without (n = 23; group 1) vs with (n = 25; group 2) LV hypertrophy (greater than 13 mm) were compared with a group of untreated non-renal hypertensive patients with LV hypertrophy (n = 11; group 3) using Doppler-echocardiography. Age and body surface area were comparable in all three groups, mean CAPD-duration (32 +/- 28 vs 26 +/- 23 months; p = NS) was comparable in renal patients. LV systolic function in echocardiography (LVEF: 62 vs 64 vs 63%) and systolic time intervals were normal and comparable in all three groups. Atrial maximum filling velocities (96 +/- 25 vs 91 +/- 25 vs 67 +/- 8 cm/s) were comparably increased, the ratio of maximal early/atrial filling velocities was comparably decreased (0.73 +/- 0.25 vs 0.77 +/- 0.21 vs 0.99 +/- 0.05) in both groups of renal patients as compared to group 3 (p less than 0.05-0.01). Atrial filling fractions were increased in all three groups, more pronounced in group 1 than in group 3 (50 +/- 11 vs 40 +/- 7%; p less than 0.05). The normal correlation of Doppler parameters with age and with LV radius/thickness ratio was altered in renal patients such that high patient age tended to have an additional negative influence on LV diastolic function of hypertrophied, but not of normal myocardium. Isovolumic relaxation time was prolonged in all three groups (134 +/- 38 vs 131 +/- 34 vs 116 +/- 17 ms; p = NS). We conclude that in patients on CAPD, diastolic LV filling is impaired both in normal and hypertrophied myocardium. High age is a factor that further attributes to diastolic dysfunction of hypertrophied myocardium in CAPD.

Age Factors↗
PubMed1990

Cardiac structure and function in continuous ambulatory peritoneal dialysis: influence of blood purification and hypercirculation.

Continuous ambulatory peritoneal dialysis (CAPD) is associated with obvious hemodynamic and blood purification advantages over intermittent hemodialysis. To determine whether this is reflected in favorable left ventricular (LV) structure and function, a group of 55 normotensive patients (aged 58.4 +/- 11.0 years) undergoing CAPD was analyzed by means of echocardiography. Characteristic findings were LV hypertrophy (158 +/- 50 gm/m2), mainly the result of septal thickening (13.3 +/- 2.8 mm), and left atrial dilatation (40.9 +/- 7.4 mm). Mean LV diameter in end diastole and end systole and posterior wall thickness were normal. Parameters of LV systolic function (ejection fraction [EF]: 62.0 +/- 13.0%; velocity of circumferential fiber shortening [Vcf]: 1.58 +/- 0.46 circ/sec) were in the upper normal range at a hyperdynamic circulatory state (cardiac index [CI] 4.67 +/- 1.82 L/min/m2. The amount of LV hypertrophy was related to the amount of hypercirculation (CI: p less than 0.001; hemoglobin: p less than 0.025) and quality of blood purification (creatinine, urea: p less than 0.02) but not to blood pressure, age, or duration of dialysis. Left atrial dilatation was inversely related to LV systolic function (EF, Vcf: p less than 0.001) and directly related to LV muscle mass (p less than 0.02). A low prevalence (13%) of pericardial effusion was independent of blood purification. We conclude that in normotensive patients receiving CAPD, a high prevalence of left atrial dilatation and asymmetric septal hypertrophy is found, the latter being related both to the amount of hypercirculation and the quality of blood purification.

Adult↗
PubMed1990

Time course of alpha 2-adrenoceptor desensitization induced by adrenaline infusion in man.

After a rapid increase in infusion rate of adrenaline to elevate the initial heart rate by more than 15%, a continuous infusion was sustained in order to maintain elevated adrenaline plasma levels. At the end of the first phase of the experiment, the thrombocyte alpha 2-adrenoceptor number (determined by radioligand binding) was significantly lowered. After the second part of the experiment, a further significant decrease in the density of binding sites was observed, while elevated adrenaline plasma levels were kept constant. The decrease in the number of binding sites was accompanied by a slight increase in affinity of the radioligand. Serum potassium concentration significantly decreased during the experiment, while other serum electrolytes showed no significant alterations.

Adult↗
PubMed1990

Effects of a modified hemodiafiltration method on low-molecular-weight protein composition in plasma.

To assess the biochemical effects of a hemodiafiltration procedure where low-molecular-weight proteins can be removed from the plasma, 7 patients with end-stage renal disease were studied during a 6-month period of high-flux dialysis as well as during a succeeding 6-month period of hemodiafiltration. Distinct changes in the plasma protein composition occurred during the hemodiafiltration period, which cannot be explained solely as a result of molecular-weight-dependent filtration. Low-molecular-weight proteins in the plasma were reduced but losses of larger proteins occurred simultaneously. It is concluded that by increasing the dose of diffusive and convective transport in hemodiafiltration the renal tubular function in the catabolism of low-molecular-weight proteins cannot be replaced. The main obstacle to achieve such a goal appears to be the low selectivity of current high-flux membranes for low-molecular-weight proteins.

Adult↗
PubMed1990

Plasma catecholamines and alpha 1-adrenoceptor function in hemodialysis-associated hypotension.

alpha 1-Adrenoceptor function and plasma catecholamine levels were investigated in chronically hemodialyzed patients with and without hemodialysis-induced hypotension. In the interdialytic period blood pressure responses as well as the mydriasis after topical application of the alpha 1-selective agonist phenylephrine were not significantly different in patients with or without hypotension during dialysis, although patients with hypotension were more susceptible to miosis induced by the muscarinergic agonist carbachol. In the normotensive group the blood pressure increasing effect of phenylephrine was attentuated after 120 min of hemodialysis therapy. Plasma noradrenaline levels were not significantly different in both groups and did not change significantly during hemodialysis, while plasma dopamine was significantly increased in the hypotensives. Thus, evidence for a pathophysiological role of a postsynaptic alpha-adrenoceptor dysfunction in hemodialysis-induced hypotension was lacking.

Blood Pressure↗
PubMed1990

Increased concentrations of a circulating sodium pump inhibitor in essential hypertension and uraemia and its partial purification from haemofiltrate.

Patients with essential hypertension have 3.2 fold and patients with chronic uraemia 11.7 fold higher serum concentrations of endogenous digitalis-like activity than normotensives (76.3 +/- 9.3 nM). Upon haemodialysis this serum activity drops to almost normal values. A low molecular factor could be partially purified from 4000 l haemofiltrate.

Aged↗