Comparative effects of acetate and bicarbonate hemodialysis on left ventricular function

To assess the comparative effects of hemodialysis with acetate versus bicarbonate base on left ventricular systolic function, we performed M-mode echocardiography on 36 patients prior to and immediately following 4-hr maintenance hemodialysis. Patients were initially dialyzed against either sodium acetate or sodium bicarbonate and 1 week later were dialyzed against the alternate base. The mean velocity of circumferential fiber shortening (mean Vcf, circumferences/s) was used to assess left ventricular systolic function. In patients with normal pre-dialysis mean Vcf hemodialysis with acetate produced no significant change in mean Vcf, whereas hemodialysis with bicarbonate produced a significant increase in mean Vcf. In patients with low pre-dialysis mean Vcf hemodialysis with either base produced a significant increase in mean Vcf. Mean Vcf values obtained after hemodialysis with bicarbonate were significantly higher than those obtained after hemodialysis with acetate, both in patients with normal and low pre-hemodialysis mean Vcf. We conclude that hemodialysis with bicarbonate produces a comparatively greater improvement in left ventricular systolic function than hemodialysis with acetate.     

Effect of hemodialysis on left ventricular systolic function in the presence and absence of beta-blockade: influence of left ventricular mass.

To assess the effect of hemodialysis on the left ventricular (LV) systolic function in the presence and absence of beta blockade, we performed echocardiography just prior to and immediately after 4-hour maintenance hemodialysis in 38 patients with end-stage renal disease. The LV systolic function was assessed in subgroups with normal and increased LV mass in both the beta blockade group (n = 19) and the non-beta blockade group (n = 19). There was a significant negative correlation between LV mass and the dialysis-induced change in the mean velocity of LV circumferential fiber shortening (mean Vcf) in both the beta blockade group (r = -0.93; p less than 0.0005) and in the non-beta blockade group (r = -0.82; p less than 0.0005). The mean dialysis-induced change in mean Vcf in the subgroup with increased LV mass in the beta blockade group (-0.02 +/- 0.11 circumferences/s) was significantly lower than the mean dialysis-induced change in mean Vcf in the non-beta blockade group (+0.12 +/- 0.04 circumferences/s; p less than 0.0005). Thus, the coexistence of increased LV mass and beta blockade significantly impedes the expected improvement of LV systolic function associated with hemodialysis.     

Left ventricular function studies in constrictive pericarditis

Left ventricular function studies were performed on five patients with constrictive pericarditis. Functional data were obtained from intracardiac pressure measurements and cineangiocardiographic films. Left ventricular end-diastolic volume(LVEDV), left ventricular end-systolic volume (LVESV), ejection fraction (EF), stroke work index (SWI), circumferential fiber shortening, and percent circumferencial shortening were significantly below normal values in the five cases. These changes are reflected mainly in the degree of pericardial restriction. Reduction in mean Vcf was also observed. Theoretically, the velocity of ventricular internal circumferential shortening is also affected by changes in ventricular volume or resting myocardial fiber length, however, in patients with constrictive pericarditis, reduction in mean Vcf suggests left ventricular dysfunction. Our clinical studies indicate that evaluation of mean Vcf is valuable in the assessment of postoperative prognoses.     

Fever in uremia: production of leukocytic pyrogen by chronic dialysis patients

Uremic patients frequently have low baseline temperatures and a blunted febrile response to infection. We investigated the first step in the generation of a febrile response, the production of leukocytic pyrogen (LP) by blood monocytes, in 12 patients on chronic hemodialysis, five patients on continuous ambulatory peritoneal dialysis (CAPD), and 17 control subjects. No significant differences were found in the amount of LP produced by hemodialysis patients, CAPD patients, and control subjects. Uremic serum did not decrease LP production by monocytes from control subjects. Hemodialysis patients who were consistently hypothermic (mean oral predialysis temperature less than or equal to 35.6 degrees F) produced as much LP as those with more normal oral temperatures (mean oral predialysis temperature greater than or equal to 36.8 degrees F). Decreased production of LP does not explain the blunted febrile response noted in patients with chronic renal failure.     

高通量血液透析联合左卡尼汀对尿毒症心肌病的临床研究

目的 高通量血液透析联合左卡尼汀对尿毒症心肌病的影响.方法 选取81例于本院门诊和住院部透析的患者,随机分成两组:实验组41例,对照组40例,所有患者均每周3次血液透析,每次4h,实验组自2012年10月开始接受高通量血液透析联合左卡尼汀治疗,对照组进行单纯的高通量血液透析治疗,两组患者都观察8个月.治疗前后检测血红蛋白、血细胞比容,做常规超声心动图,观察左心室舒张期末内径(LVIDd)、左心室收缩末期内径(LVIDs)、室间隔舒张期末期厚度(IVSd)、左室心肌质量(LVM)、左室心肌质量指数(LVMI)、左室后壁厚度(PWTH)、射血分数(EF)、左心室的舒张功能(EPSS)等.结果 治疗8个月后,实验组患者的血红蛋白、血细胞比容与对照组比较明显升高(P＜0.05),超声心动图EF值明显升高,LVIDd、LVIDs、IVSd、PWTH、LVM、LVMI明显降低,差异均有统计学意义(P＜0.05).结论 高通量血液透析联合左卡尼汀在改善尿毒症心肌病患者心肌重构及心功能方面有较好的疗效.     

Serum bile acids and pruritus in hemodialysis patients

BACKGROUND: Chronic renal failure (CRF) patients usually suffer from pruritus. The pathophysiology of pruritus is still incompletely understood. SUBJECTS, MATERIALS AND METHODS: In this paper we determined serum total bile acids (STBA) in hemodialysis patients with advanced CRF (ACRF) in order to obtain STBA concentration in predialysis, to assess their probable relation among patients with pruritus and in postdialysis using a polysulfone membrane for dialysis. STBA were determined in 49 ACRF patients with chronic hemodialysis and values were compared to 20 control subjects. Hemodialysis patients were divided in two groups: with and without pruritus. In all these patients, month of renal replacement therapy, diabetic patients, dose of dialysis (Kt/V), viral markers, serum creatinine, serum glucose, aspartate and alanine aminotransferase, alkaline phosphatase, hematocrits and albumin were determined. The intensity of itching among pruritic patients was measured by a score system: mild (M), moderate (MO) and severe (S). RESULTS: No significant differences were found in patients with and without pruritus in months of renal replacement therapy, duration of dialysis or dose of dialysis (Kt/V). STBA were determined in all ACRF patients in predialysis and they showed significant differences compared to controls (p < 0.05), however, no differences were observed in the results obtained when control subjects were compared to ACRF patients without pruritus. Also in predialysis, pruritic patients showed significant differences in STBA compared to patients without pruritus (p < 0.001). STBA concentration showed a significant decrease in postdialysis using a polysulfone membrane in ACRF patients with and without pruritus. Finally, correlation with STBA and itch score of pruritus was significant (p < 0.02). CONCLUSION: Hemodialysis patients with ACRF and pruritus showed an increase of STBA in predialysis and a decrease in postdialysis.     

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.     

Subjective assessment of left ventricular preload using transesophageal echocardiography: corresponding pulmonary artery occlusion pressures.

OBJECTIVE: To record pulmonary artery occlusion pressures (PAOPs) in patients whose left ventricular preload reserve was subjectively determined using transesophageal echocardiography (TEE). DESIGN: Prospective, blinded, nonrandomized. SETTING: University hospital. PARTICIPANTS: Twenty-three patients with well-preserved left ventricular function during nonemergent cardiac surgery. INTERVENTIONS: After separation from cardiopulmonary bypass, patients received repeated boluses of fluid volume through the aortic inflow cannula while being monitored with TEE. The endpoint for this fluid administration was a plateau in left ventricular fractional area change and end-diastolic area. This point at which additional fluid failed to cause noticeable increases in left ventricular end-diastolic area and fractional area change was defined as the preload reserve volume. After reaching the preload reserve volume, the PAOP was measured, as were the systolic blood pressure, left ventricular fractional area change, and end-diastolic area. MEASUREMENTS AND MAIN RESULTS: The mean PAOP for all patients at the time of achieving preload reserve volume was 18.6 +/- 2.9 mmHg. In 8 patients, the PAOP corresponding to preload reserve volume was elevated (20 to 25 mmHg). The remaining 15 patients had PAOPs ranging from 13 to 19 mmHg. When these 2 groups were compared with respect to left ventricular end-diastolic area, fractional area change, and systolic blood pressure, there were no significant differences between groups. The left ventricular wall thickness was significantly greater, however, in the group with elevated PAOP (1.37 +/- 0.04 cm) when compared with the group with normal ventricular filling pressures (1.05 +/- 0.15 cm) (p = 0.001). CONCLUSIONS: In patients with well-preserved left ventricular function and normal wall thickness, preload reserve volumes subjectively determined by TEE corresponded to a range of filling pressures historically targeted to maximize cardiac performance (13 to 19 mmHg). In a subset of patients with increased wall thickness, however, subjective determination of preload reserve was associated with filling pressures that were higher than traditionally considered optimal (20 to 25 mmHg). Similarities in left ventricular fractional area change and end-diastolic area between these 2 groups suggest that patients with elevated filling pressures had decreased ventricular compliance and were managed correctly with higher than usual PAOPs.     

Dialysis-induced alterations in left ventricular filling: mechanisms and clinical significance

Quantitative two-dimensional (2-D) and Doppler echocardiography were used to determine whether hemodialysis results in alterations in left ventricular (LV) diastolic filling that might contribute to dialysis-induced hypotension, as well as to assess whether any hemodynamic variables or indices of diastolic filling might be used to identify which patients were at the greatest risk of becoming hemodynamically unstable during dialysis. Sixteen male patients undergoing routine maintenance hemodialysis for end-stage renal disease were prospectively studied before and after hemodialysis. Following hemodialysis there was a significant prolongation (P less than 0.05) in LV isovolumetric relaxation time (IVRT), as well as a significant reduction in the rate and extent of early rapid ventricular filling (P less than 0.005); in contrast, late atrial-assisted filling did not change significantly. A multiple stepwise linear regression analysis of predialysis hemodynamic parameters and noninvasive indices of LV filling showed that there was a significant independent inverse relationship between the frequency of dialysis-related hypotensive episodes and the duration of early LV filling (r = -0.81; P less than 0.001). These results suggest that hemodialysis results in discrete alterations in early LV filling, with no significant compensatory increase in late atrial-assisted ventricular filling. Further, patients with the shortest early LV filling times appeared to have the greatest predilection for becoming hemodynamically unstable during dialysis.     

Uremic cardiomyopathy: potential role of vitamin D and parathyroid hormone

44 patients receiving regular hemodialysis therapy were investigated using M-mode echocardiography and systolic time intervals to examine the effects of parathyroid hormone (PTH) and vitamin D on left ventricular function. 12 patients were treated with 1 microgram daily of 1, alpha-hydroxycholecalciferol for 6 weeks, which produced a decrease in plasma PTH concentration from 1,883 +/- 226 to 1,123 +/- 289 ng/l. Fractional fibre shortening (FS) increased from 34.6 to 37.6% (p less than 0.025) and mean velocity of fibre shortening (Vcf) increased from 1.21 to 1.32 circ/s (p less than 0.01). A second group of 20 patients was studied before and after the plasma magnesium concentration was increased from 1.25 to 1.70 mmol/l, resulting in a fall in plasma PTH concentration from 546 to 418 ng/l (p less than 0.001). This was associated with an increase in both FS from 32.4 to 34.3%, and Vcf from 1.19 to 1.21 circ/s. A third group of 6 patients with severe hyperparathyroidism underwent total parathyroidectomy, FS increased from 34.9 to 36.3% and Vcf increased from 1.22 to 1.38 circ/s. In conclusion, our results indicate that vitamin D and PTH do influence left ventricular function in uremic patients on chronic hemodialysis, and that a reduction in plasma PTH levels is beneficial to the uremic heart.     

Baroreceptor, not left ventricular, dysfunction is the cause of hemodialysis hypotension

Many patients with chronic renal failure experience profound hypotension during hemodialysis. This has been attributed both to autonomic and ventricular dysfunction. In an attempt to distinguish which, if either, is important in this role, we assessed both autonomic and left ventricular function in 10 such patients. Cardioactive medication was stopped 24 hours prior to the investigations. Autonomic function was assessed from day/night blood pressure and heart rate variation and from the hemodynamic response to tilting and the Valsalva maneuver using an intra-arterial ambulatory monitoring technique. Left ventricular function was assessed scintigraphically both before and during hemodialysis. Day/night variation was significantly reduced in the patients with chronic renal failure (BP 13/7 +/- 8/6 mmHg, HR 5 +/- 4) compared with a control population (BP 36/28 +/- 10/5 mmHg, HR 19 +/- 6). Nine patients had a "square wave" response to the Valsalva maneuver. Both of these abnormalities are usually seen in patients with heart failure and are attributed to volume overload and a consequent failure of baroreceptor response. Blood pressure fell during hemodialysis (mean fall 40/22 +/- 20/10 mmHg) in all patients, but heart rate did not change (-2 +/- 16) despite the hypotension. All patients had a normal or high resting ejection fraction (mean 66%, range 55-79%), and there was no change during dialysis. This indicates that the hypotension was not due to left ventricular dysfunction in this group of patients, but to a failure of the baroreceptor response to volume depletion during hemodialysis.     

Transesophageal echocardiographic dimensional analysis of four cardiac chambers during positive end-expiratory pressure

The authors examined the effects of positive end-expiratory pressure (PEEP) on cardiac function by dimensional analysis of the four heart chambers using M-mode transesophageal echocardiography (TEE). The accuracy of cardiac output (CO) calculated from TEE was confirmed by its close correlation (r = 0.97) with CO, determined by the thermodilution technique. The reliability of TEE also was confirmed by excellent correlation (r = 0.95) between left ventricular end-diastolic (LVEDD) and end-systolic (LVESD) dimensions measured by the two-dimensional precordial echocardiography and those by TEE. With 10 cmH2O PEEP LVEDD decreased from its level during zero end-expiratory pressure (ZEEP), and the calculated stroke volume also decreased. These decreases were greater during 15 cmH2O PEEP, where heart rate increased slightly but significantly. Ejection fraction (EF) and fractional shortening (FS), as a whole, did not change significantly. Mean velocity of circumferential fiber shortening (mean Vcf) significantly increased and LVESD significantly decreased with PEEP. Although systolic blood pressure (SBP) significantly decreased, the (SBP-PEEP value)/LVESD ratio was not changed with PEEP. Such measures of left ventricular systolic function as EF, FS, mean Vcf, and (SBP-PEEP value)/LVESD were not decreased. Right ventricular end-diastolic dimension decreased with PEEP. Right atrial end-diastolic dimension began to decrease immediately after PEEP was initiated, whereas left atrial end-diastolic dimension began to decrease a few seconds later, suggesting that left ventricular preload decreased as a result of a decrease in right ventricular preload. The authors therefore conclude that CO was decreased as a result of the decrease in right and left ventricular preloads.     

Clinical and pathologic characteristics of dilated cardiomyopathy in hemodialysis patients

BACKGROUND: Some dialysis patients have impaired left ventricular (LV) function without coronary artery disease. The pathologic changes and prognoses of these patients have not been well described. METHODS: We performed LV endomyocardial biopsies on 40 hemodialysis patients with dilated cardiomyopathy (DCM; an ejection fraction <50% and a left ventricular end-diastolic volume index >90 mL/m(2) without coronary artery disease), and on 50 nondialysis patients with idiopathic DCM as the control group. Following LV biopsies, the patients were followed-up for a mean of 3.1 +/- 2.3 years. RESULTS: The pathologic characteristics of the dialysis group were severe myocyte hypertrophy (the mean myocyte diameter across the nucleus: 37.6 +/- 10.5 mum vs. 25.6 +/- 7.7 mum, P= 0.001), myocyte disarray (30%), and extensive fibrosis (the mean percent area of left ventricular fibrosis: 22.3 +/- 18.4% vs. 21.3 +/- 14.6%, P= NS). These pathologic characteristics resembled the dilated phase of hypertrophic cardiomyopathy. In the dialysis group, a high percent area of LV fibrosis was the only significant predictor of cardiac death by multivariate analysis (P= 0.02). The 3-year cumulative event-free survival rate for cardiac death in dialysis patients with severe fibrosis (more than 30%) was 42%, while that for patients without severe fibrosis was 82% (P= 0.03). CONCLUSION: The pathologic characteristics of the heart in dialysis patients with DCM are interstitial fibrosis and severe myocyte hypertrophy with occasional disarray. The extent of LV fibrosis is a strong predictor of cardiac death. Careful follow-up and treatment are necessary for dialysis patients with a high percent area of LV fibrosis.     

Cardiac function and cardiovascular hormone balance during hemodialysis with special reference to atrial natriuretic peptide

Echocardiographically determined left ventricular function and cardiovascular hormone balance were assessed before and after hemodialysis in 10 patients who had been on hemodialysis for 4 months to 15 years. Plasma levels of atrial natriuretic peptide (ANP), antidiuretic hormone (ADH), renin activity and aldosterone were determined. All patients had vector- and echocardiographic evidences of slight to moderate left ventricular hypertrophy. The body weight decreased 2.0 kg (3.3 +/- 0.5%) with dialysis. Nine out of ten patients showed a slightly reduced ejection fraction that normalized after dialysis (p less than 0.05). Left atrial and ventricular systolic dimensions were around the upper reference limit before dialysis with a decrease after dialysis (p less than 0.05 and p less than 0.02, respectively). The levels of ANP decreased with dialysis from 2-17 times to 1 to 15 times the upper reference value in nine out of the ten patients. In the whole group the decrease was 117 +/- 35% (p less than 0.005). A significant regression was obtained between percentage decrease of body weight and percentage change of ANP (r = 0.67; p less than 0.05). The plasma concentration of ADH did not change following dialysis but the mean value was significantly higher than the mean value of the reference group of the laboratory (p less than 0.05 before and p less than 0.005 after dialysis). Renin activity and aldosterone levels were low and did not change during dialysis. In conclusion, the slight left ventricular hypertrophy may partly be a response to volume overload with hyperdynamic circulation and partly to metabolically depressed myocardial function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Echocardiographic assessment of left ventricular function in patients with chronic uremia

Cardiac function was determined non-invasively in 7 patients (average age 24 years) with chronic uremia. Each was on maintenance hemodialysis. Echocardiograms and carotid pulse tracings were recorded 30 minutes prior to dialysis, and again 30 minutes, 24 and 48 hours following hemodialysis. End-diastolic and end-systolic diameters averaged 5.4 +/- 0.2 and 3.4 +/- 0.1 cm, respectively before and 5.0 +/- 0.2 and 3.2 +/- 0.1 cm immediately after hemodialysis (P less than 0.05 for both). Calculated stroke volume fell from 92.1 +/- 8.8 to 76.7 +/- 10.5 ml (P less than 0.025). Heart rate increased minimally, and average cardiac output was not significantly increased. Following dialysis, body weight and systolic and diastolic blood pressures fell significantly. Thus preload as well as afterload declined. Because of the fall in both stroke volume and end-diastolic volume, a shift along the ventricular function curve downwards and to the left occurred implying diminished cardiac pumping function. Nonetheless the indices of myocardial contractility were normal and showed no change from pre-dialysis value. During the 48 hour interval following hemodialysis all measured and calculated values returned to pre-dialysis levels. Thus organic heart disease as evaluated by non-invasive techniques does not appear to be a necessary sequel to kidney failure, at least in young patients in a hemodialysis program. Gross abnormalities of myocardial function may be absent for at least seven years after the onset of chronic uremia.     

可调钠透析防治高危血液透析患者低血压研究

目的：观察可调钠透析（PHD）在高危人群（高龄、糖尿病肾病及心功能不稳定）血液透析中防治低血压的作用。方法：选择30例维持性血液透析中的高危患者透析，治疗分两阶段进行，第1月行普通透析（CHD）为A组，透析液钠浓度138mmol／L，第2月行可调钠透析（PHD）为B组，透析液钠离子浓度由148mmol／L，线性下降到135mmol／L，透析时间均4．5h，患者自身交叉对照，两者血流速相等，脱水量恒定，透析过程中监测透析前后血清钠浓度，监测透析过程中低血压发生率。结果：CHD组与PHI）组相比，透析前后血清钠浓度无明显差异（P〉0．05）。CHD组与PHD组相比，PHD组低血压发生率较CHD组明显降低（p〈0．01）。与CHD相比，PHD的作用以不增加患者的钠负荷为代价，不造成透析间期体重增长过多。结论：PHD组可明显减少维持血液透析中高危人群的低血压的发生率。     

The effects of reprocessing cuprophane and polysulfone dialyzers on beta 2-microglobulin removal from hemodialysis patients

To further define the relationship between dialyzer reuse and the removal of beta 2-microglobulin (beta 2M) during dialysis, 26 patients who received hemodialysis were studied. Thirteen patients were dialyzed with conventional cuprophane dialyzers, and thirteen patients were dialyzed with high-flux polysulfone dialyzers. Patients in each group were dialyzed with only new dialyzers during the primary-use phase of the study, and reprocessed dialyzers during the reuse phase. Dialyzers were used six times during the reuse phase. Serum beta 2M levels were measured both predialysis and postdialysis, and adjusted for fluid loss. Dialysis with conventional cuprophane new dialyzers during the primary-use phase of the study resulted in a 3.3% increase in serum beta 2M levels, and a 2.4% increase in serum beta 2M levels during the reuse phase. The difference in the change of the concentration of beta 2M between primary-use and reuse phases was not statistically significant. Dialysis with high-flux polysulfone new dialyzers during the primary-use phase was associated with a decrease of 59.5% in the mean postdialysis concentration of serum beta 2M compared with the predialysis level. A corresponding decrease of 62.6% in serum beta 2M levels was observed after dialysis with high-flux polysulfone reprocessed dialyzers during the reuse phase. These data show no evidence of an adverse effect on the clearance of beta 2M during dialysis from the reuse of dialyzers up to six times. The results confirm previous studies that have reported that high-flux dialysis with polysulfone dialyzers removes substantial amounts of beta 2M, and dialysis with conventional cuprophane dialyzers does not.     

Asymmetric septal hypertrophy and left atrial dilatation in patients with end-stage renal disease on long-term hemodialysis

Some literature reports associate a reduced weekly duration of treatment (3 x 4 h/week) for patients on maintenance hemodialysis with an increased cardiovascular mortality. To determine whether the improved survival of patients on long weekly hemodialysis (LHD: 3 x 8 h/week) can be associated with different cardiac changes, the cardiac characteristics of a group of 50 patients on LHD were analyzed in a non-invasive assessment. The main findings were an increased left ventricular (LV) muscle mass (176 + 54 g/m2), mass/volume ratio (1.69 + 0.37 g/ml) and left atrial diameter (39.7 + 5.7 mm). The increase in LV muscle mass was due mainly to a high prevalence of asymmetric septal thickening. The ratio septum/LV posterior wall was directly correlated with the left atrial diameter (r = 0.52), LV end-diastolic diameters were inversely correlated with hemoglobin concentration (r = 0.62). LV dilatation and/or LV systolic dysfunction were not characteristic findings: Only 6% of patients had a moderately enlarged (less than 65 mm) LV diameter, LV ejection fraction was decreased in 12%. There was no significant correlation between the degree of LV hypertrophy or left atrial dilatation and patient age, total dialysis duration, interdialytic weight gain, hemoglobin concentration, parameters of blood purification, blood pressure before and after dialysis, history of hypertension. We conclude that cardiac characteristics in patients on LHD are comparable to those described for large patient groups on short hemodialysis. Our findings do not explain improved survival on LHD.     

Hemodynamic Changes During Acetate and Bicarbonate Hemodialysis

In a crossover, double-blind comparison, circulatory changes induced by hemodialysis with bicarbonate versus acetate dialysate were evaluated at the first exposure as well as after 2 weeks of acclimatization to each dialysate. Hemodialysis with bicarbonate dialysate resulted in only minor changes in blood pressure and left ventricular (LV) function as assessed by M-mode echocardiography. In contrast, the first exposure to acetate resulted in significant decreases in systolic (30 mm Hg) and diastolic (17 mm Hg) blood pressure as well as in LV end-diastolic and end-systolic dimensions (5-6 mm) and a rise in ejection fraction. After acclimatization, tolerance developed for the arterial vasodilatory effects of acetate, but not for the venous vasodilatory effect (persistent decrease in LV end-diastolic dimension). These results indicate that some of the circulatory changes induced by hemodialysis may be related more to the acetate infused than to fluid losses or relative autonomic insufficiency.     

Doppler echocardiographic findings in dialysis patients

We used Doppler echocardiographic techniques firstly to examine left ventricular (LV) filling patterns in dialysis patients, secondly to analyse whether Doppler echocardiographic left ventricular filling pattern is different in patients with recurrent intradialytic hypotension, and thirdly to study the relation between blood pressure decrease during volume subtraction and left ventricular filling pattern. Indices of left ventricular filling patterns of 47 dialysis patients were consistently different when compared to normotensive healthy controls. To further assess the relation of left ventricular filling pattern to blood pressure stability on dialysis, we first compared 24 patients with stable intradialytic blood pressure (BP) and 23 patients with one or more episodes or intradialytic hypotension per month. Patients with recurrent intradialytic hypotension had lower predialysis blood pressure (MAP 89 +/- 13 vs 96 +/- 14 mmHg), more severe concentric hypertrophy (left ventricular mass/volume ratio 2.7 +/- 1.4 vs 2.0 +/- 0.7), and impaired left ventricular filling (Doppler) as indicated by the ratio of early diastolic vs late (atrial) filling (0.66 +/- 0.2 vs 0.95 +/- 0.22). Subsequently we assessed by Doppler technique the effect of a predetermined rate of volume subtraction (during one dialysis session) in patients with or without recurrent intradialytic hypotension. Diastolic filling indices deteriorated consistently prior to the reduction in blood pressure (early diastolic filling 26.8 +/- 15.2 vs 45.4 +/- 10.9% of diastolic filling). It is suggested that impaired left ventricular filling, presumably reflecting disturbed left ventricular compliance, is common in dialysis patients. Findings by noninvasive Doppler techniques suggest a role of abnormal left ventricular distensibility in recurrent dialysis hypotension.