Usefulness of left ventricular size and function in predicting survival in chronic dialysis patients with diabetes mellitus

The Diabetic Cardiorenal Nexus

The end-stage of the clinical combination of heart failure and kidney disease has become known as cardiorenal syndrome. Adverse consequences related to diabetes, hyperlipidemia, obesity, hypertension and renal impairment on cardiovascular function, morbidity and mortality are well known. Guidelines for the treatment of these risk factors have led to the improved prognosis of patients with coronary artery disease and reduced ejection fraction. Heart failure hospital admissions and readmission often occur, however, in the presence of metabolic, renal dysfunction and relatively preserved systolic function. In this domain, few advances have been described. Diabetes, kidney and cardiac dysfunction act synergistically to magnify healthcare costs. Current therapy relies on improving hemodynamic factors destructive to both the heart and kidney. We consider that additional hemodynamic solutions may be limited without the use of animal models focusing on the cardiomyocyte, nephron and extracellular matrices. We review herein potential common pathophysiologic targets for treatment to prevent and ameliorate this syndrome.

Echocardiography-based score to predict outcome after renal transplantation

BACKGROUND

Given the high cardiac mortality of renal transplant recipients, identification of high-risk patients is important to offer appropriate treatment before transplantation.

AIM

To determine patients with high mortality after renal transplantation despite selection according to current criteria.

METHODS

Preoperative parameters were collected from 203 renal transplant recipients over a follow-up time of 3.6 (1.9) years. The primary end point was all-cause mortality.

RESULTS

22 deaths (11%) and 12 cardiac failures (6%) were observed. Non-survivors were older (p< or =0.001), had larger left ventricular end-systolic diameter (LVSD) (p< or =0.001) and end-diastolic diameter (p = 0.002), and lower ejection fraction (p< or =0.001). Left ventricular mass index (p = 0.001), maximal wall thickness (p = 0.006) and the proportion with mitral annular calcification (p = 0.001) were significantly higher in the non-survivors. The risk factors for ischaemic heart disease and exercise test data were not significantly different between the two groups. Four independent predictors of mortality after renal transplantation were identified: age > or =50 years (p = 0.002), LVESD > or =3.5 cm (p = 0.002), maximal wall thickness > or =1.4 cm (p = 0.014) and mitral annular calcification (p = 0.036). The 5-year survival estimates for 0, 1, 2 and 3 prognostic factors were 96%, 86%, 69% and 38%, respectively. No patient had four prognostic factors. In patients > or =50 years, the 5-year survival estimates for 0, 1 and 2 additional prognostic factors were 73%, 45% and 18%, respectively.

CONCLUSION

In addition to selection according to current guidelines, age and three conventional echocardiography parameters may further improve risk stratification before renal transplantation.

Influence of fluid volume variations on the calculated value of the left ventricular mass measured by echocardiogram in patients submitted to hemodialysis

The left ventricular mass (LVM) measurement is of major importance for renal patients, as ventricular hypertrophy is an important prognostic index. The echocardiogram of the ventricular mass is larger before than it is after hemodialysis, which can confuse data interpretation. The aim of this work is to study the influence of alterations in fluid volume on the variations in measurements of ventricular mass observed during the course of a hemodialysis. Sixteen patients with chronic renal insufficiency in hemodialysis were evaluated at the Dialysis Unit of the University Hospital-UNESP, Botucatu, São Paulo State. The left ventricular mass was calculated from echocardiograms taken before and after hemodialysis and simultaneous ultra-filtration (12 patients: UF GROUP) and before and after hemodialysis isovolemic phase with sequential ultra-filtration (10 patients: ISO GROUP). Six of these patients were submitted to measurements of left ventricular mass before and after hemodialysis in both isovolemic and simultaneous ultra-filtration procedures. In the UF group, there was significant reduction in the following parameters before and after dialysis: diastolic diameter from 54.0 +/- 6.0mm to 45.6 +/- 7.6mm; left ventricular mass from 342 +/- 114 g to 265 +/- 117 g; and its respective index (IMVE) from 214 +/- 68 g/m2 to 168 +/- 71 g/m2. The ISO group showed no statistically significant variation. The behavior of the variables of six patients submitted to both observations confirm these results. In conclusion, the variations in echocardiogram measurements of the left ventricula mass relating to hemodialysis appear to be induced by alterations of the volemic condition.

Cardiac disease in diabetic end-stage renal disease

Little is known about the epidemiology of cardiac disease in diabetic end-stage renal disease. We therefore prospectively followed a cohort of 433 patients who survived 6 months after the inception of dialysis therapy for an average of 41 months. Clinical and echocardiographic data were collected yearly. At baseline, diabetic patients (n = 116) had more echocardiographic concentric left ventricular hypertrophy (50 vs 38%, p = 0.04), clinically diagnosed ischaemic heart disease (32 vs 18%, p = 0.003) and cardiac failure (48 vs 24%, p < 0.00001) than non-diabetic patients (n = 317). After adjusting for age and sex, diabetic patients had similar rates of progression of echocardiographic disorders, and de novo cardiac failure, but higher rates of de novo clinically diagnosed ischaemic heart disease (RR 3.2, p = 0.0002), overall mortality (RR 2.3, p < 0.0001) and cardiovascular mortality (RR 2.6, p < 0.0001) than non-diabetic patients. Mortality was higher in diabetic patients following admission for clinically diagnosed ischaemic heart disease (RR 1.7, p = 0.05) and cardiac failure (RR 2.2, p = 0.0003). Among diabetic patients older age, left ventricular hypertrophy, smoking, clinically diagnosed ischaemic heart disease, cardiac failure and hypoalbuminaemia were independently associated with mortality. The excessive cardiac morbidity and mortality of diabetic patients seem to be mediated via ischaemic disease, rather than progression of cardiomyopathy while on dialysis therapy. Potentially remediable risk factors include smoking, left ventricular hypertrophy, and hypoalbuminaemia.

Report from the 1995 Core Indicators for Peritoneal Dialysis Study Group

The 1995 Peritoneal Dialysis Core Indicators Study was conducted by the Health Care Financing Administration to ascertain standard practices and outcomes in chronic peritoneal dialysis patients. Data from 1,202 patients who did not receive hemodialysis but who were on chronic ambulatory peritoneal dialysis (CAPD) for at least part of the 6-month period between November 1, 1994, and April 30, 1995, are reported. The mean serum albumin level for this cohort was 3.5 g/dL by the bromcresol green method and 3.2 g/dL by the bromcresol purple method. Data sufficient to calculate a weekly Kt/V(urea) or weekly creatinine clearance were available for only 34% of patient submissions. In these patients, the median weekly Kt/V(urea) was 1.7 using a fixed value for V of 0.58 x body weight and was 2.0 using the Watson equation to calculate V; the median weekly creatinine clearance was 60.7 L/wk/1.73 m2. The mean hematocrit for this cohort was 32% and the average weekly recombinant human erythropoietin (rHmEPO) dose was 115 u/kg. Hematocrit values < or = 30% were found in 50% of black patients and 31% of white patients. The average blood pressure among peritoneal dialysis patients was 139/80 mm Hg, with 29% of patients having a systolic blood pressure exceeding 150 mm Hg and 18% a diastolic blood pressure greater than 90 mm Hg. In summary, serum albumin levels were significantly lower in peritoneal dialysis patients than in hemodialysis patients. Approximately one third of peritoneal dialysis patients did not have an adequacy measure obtained during the 6-month observation period. A significant minority of patients had either inadequately treated anemia of chronic renal disease or hypertension. There is an opportunity to substantially improve the medical care provided to chronic peritoneal dialysis patients.

Preliminary screening of the relationship of serum lipids to survival of chronic dialysis patients

To assess the predictive value of serum lipid measurements in dialysis patients once the initial decrease on early dialysis had occurred, we obtained random serum cholesterol and triglyceride levels in stable, chronic dialysis patients who were then followed up to 9 years. Derived LDL (DLDL) was estimated by the Friedewald formula, calculated for all HDL levels between 30 and 45 mg/dL, and evaluated statistically against a panel of vascular disease markers, including clinical assessment for coronary, peripheral, and cerebrovascular disease; ECG, both standard and ambulatory; two-dimensional echocardiogram; and medications. Survival was calculated from entry (not dialysis onset) for 58 hemodialysis and 33 peritoneal dialysis patients. The 91 patients (49 males, 74 diabetics) were divided by cholesterol level (> or = 175 mg/dL = 53, < 175 = 38), triglyceride (> or = 175 mg/dL = 55, < 175 = 36), and DLDL (> or = 75 = 58, < 75 = 24). High total cholesterol was present in a larger proportion of females than low cholesterol, but groups were not different with respect to all vascular determinants, including survival (mean = 33.4 months vs. 43.2, p = NS). High vs. low triglyceride groups were not different with respect to vascular indicators, except for both incidence of abnormal standard ECG (69% vs. 42%, p < 0.05) and survivals (mean = 42.0 vs. 30.7, p < 0.05; 1 year = 80% vs. 56%, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative evaluation for diabetic renal transplantation: impact of clinical, laboratory, and echocardiographic parameters on patient and allograft survival

OBJECTIVE

To assess the impact on renal transplant patients and graft survival of clinical, laboratory, and echocardiographic parameters commonly measured prior to surgery.

PATIENTS

Forty-seven consecutive diabetics with preoperative echocardiograms at the time of transplantation.

METHODS

Clinical history, standard chest roentgenogram, electrocardiogram, blood tests, echocardiograms, and HLA testing at baseline; follow-up from 2 to 7 years with periodic reassessment of graft function.

RESULTS

Patient survival did not appear to be influenced by age, sex, or type of allograft. A history of either myocardial infarction, congestive heart failure, or angina was present in 15 patients with 3-year survival of 50% (72% if not present, p less than 0.05). Histocompatibility testing did not impact on survival. Serum sodium, potassium, calcium, phosphate, and calcium-phosphate product did not discern different survival groups. A hematocrit greater than 30% was present in 15 patients with 3-year survival of 43% (73% if not present, p less than 0.05). Greater than 10% antibody sensitization of the recipient resulted in a 3-year survival of 38% in eight patients (68% if not present, p less than 0.05). Radiologic evidence of cardiomegaly or congestive heart failure and standard electrocardiographic evidence for left ventricular hypertrophy or strain did not impact on survival. Echocardiographic measurements of left ventricular end-diastolic diameter, posterior wall thickness, or ejection fraction were also not predictive. Increased end-systolic diameter (10 patients, 30% 3-year survival versus 69%, p less than 0.05) and decreased velocity of circumferential fiber shortening (11 patients, 45% 3-year survival versus 71%, p less than 0.05) both appeared to be related to survival. Increased accuracy of prediction could be obtained by adding risk factors so that a history of coronary artery disease and increased end-systolic diameter predicted 3-year survival of 42% versus 82% if neither was present. In terms of graft survival, no clinical, radiographic, or electrocardiographic result yielded predictive information. Among the laboratory tests, only highly antibody-sensitized patients (eight patients, 0% 3-year survival versus 66% 3-year survival, p less than 0.001) showed different survival patterns. Echocardiographic elevated end-systolic diameter predicted a significantly (p less than 0.001) decreased graft survival (3-year survival 33% versus 63%).

CONCLUSION

Preoperative prediction of patient and graft survival in diabetic renal transplantation may be enhanced by echocardiographic assessment of systolic load and function. For patients with normal systolic function, whose hematocrit is below 30%, with preformed antibodies less than 10%, renal transplantation has an excellent prognosis; invasive cardiac procedures are not likely required. Since these risk factors are likely additive, a high-risk group may be identified. These latter patients should undergo coronary angiography.