Gloria M. Kent

Cardiac disease in diabetic end-stage renal disease

SummaryLittle 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.

Cardiac Function and Hematocrit Level

Patients on dialysis have an age-adjusted death rate 3.5 times that of the general population. The most common cause of death in patients on dialysis is cardiovascular disease. We prospectively followed a cohort of 433 patients in three centers for a mean of 41 months. Mean hemoglobin level at the beginning of dialysis was 8.39 (+/- 1.7) g/dL, and the mean hemoglobin level during follow-up was 8.84 (+/- 1.5) g/dL. Using Coxs regression model, we found that anemia predicted mortality independently of age, diabetes mellitus, cardiac failure, hypoalbuminemia, serum creatinine, mean arterial pressure, or echocardiographic heart disease. The independent relative risk (RR) of mortality was 1.18 per 1.0 g/dL decrease in hemoglobin level. Anemia also independently predicted the de novo occurrence of congestive heart failure when the same covariates were controlled for (RR, 1.49 per 1.0 g/dL decrease). Anemia was also independently predictive of heart failure at the start of dialysis (RR, 1.14 per 1.0 g/dL decrease) and heart failure recurrence (RR, 1.25 per 1.0 g/dL decrease). Left ventricular hypertrophy is present in 75% of patients on dialysis at the start of therapy for end-stage renal disease. It independently predicts mortality. Our prospective cohort study identified increasing age, hypertension, and anemia as risk factors for its development. One controlled study and several uncontrolled studies demonstrated improvement (but not complete regression) of elevated left ventricular mass in patients on dialysis treated with recombinant human erythropoietin (epoetin).

Long-term changes in left ventricular hypertrophy after renal transplantation.

Background. Concentric and eccentric left ventricular hypertrophy are common progressive disorders in dialysis patients and are associated with cardiac failure and death. Although partial regression of these abnormalities is known to occur during the first posttransplant year, their long-term evolution is unknown. Methods. A total of 143 of 433 dialysis patients participating in a long-term prospective cohort study received renal transplants. Laboratory parameters were assessed monthly. Echocardiography was performed annually. Left ventricular mass index (LVMI) and cavity volume index were calculated according to standard formulae. Multiple linear regression was used to model change in LVMI as a function of baseline clinical and laboratory variables. Results. LVMI fell from 161 g/m2 at 1 year to 146 g/m2 (P =0.009) g/m2 after 2 years. No further regression was seen in years 3 and 4. Left ventricular volume index showed similar trends, with a decline from year 1 to year 2 (P =0.05) followed by stabilization in years 3 and 4. Older age, long duration of hypertension, need for more than one antihypertensive, high pulse pressure in normal-size hearts, and low pulse pressure in dilated hearts were significantly associated with failure of regression of LVMI between the first and second years (MLR, P <0.000001, r2=0.57). Conclusions. Regression of left ventricular hypertrophy continues beyond the first year after renal transplantation, reaching a nadir at 2 years and persisting into the third and fourth posttransplant years. Failure to regress was associated with older age, hypertension, high pulse pressure in normal-size hearts and low pulse pressure in dilated hearts.

A Comparison of Nonionic, Low-Osmolality Radiocontrast Agents with Ionic, High-Osmolality Agents during Cardiac Catheterization

BACKGROUND Nonionic, low-osmolality radiocontrast agents are used frequently because they are believed to be safer than ionic, high-osmolality agents, but they are also more expensive. We conducted a randomized trial to compare the incidence of adverse events after the administration of ionic, high-osmolality and of non-ionic, low-osmolality radiocontrast agents during cardiac angiography. METHODS We compared the need to treat patients for adverse reactions and the frequency and severity of specific hemodynamic, systemic, and symptomatic side effects in two groups of patients randomly assigned to receive either ionic, high-osmolality or nonionic, low-osmolality radiocontrast material, and also in 366 patients who could not be randomized. RESULTS Treatment for adverse events was required in 213 of 737 patients who received high-osmolality contrast agents (29 percent) but in only 69 of 753 patients who received nonionic agents (9 percent) (95 percent confidence interval for the percent difference, 15.9 to 23.6 percent). Hemodynamic deterioration and symptoms also occurred more often in the high-osmolality group, as did severe or prolonged reactions (2.9 percent, as compared with 0.8 percent in the nonionic group; P = 0.035). The severe reactions were largely confined to patients with severe cardiac disease. Multivariate analysis showed that the presence of severe coronary disease and unstable angina were predictors of clinically important adverse reactions. If all the patients in our randomized trial had been given nonionic contrast material, the incremental cost per procedure would have been

The reliability and validity of echocardiographic measurement of left ventricular mass index in hemodialysis patients.

89. CONCLUSIONS Nonionic, low-osmolality contrast material is better tolerated during cardiac angiography than ionic, high-osmolality contrast material. Since cost constraints may prevent the universal use of nonionic contrast material, its selective use in patients with severe cardiac disease could be considered.

Chapter 7 An Observational and Theoretical Synthesis of Magma Chamber Geometry and Crustal Genesis along a Mid-ocean Ridge Spreading Center

We assessed the reliability and validity of a formula, based on echocardiographically derived parameters, to calculate left ventricular mass index (LVMI) in a group of 15 chronic hemodialysis patients. All patients had M-mode echocardiography before and after a hemodialysis session. Echocardiograms were interpreted by 2 observers blind to each others measurements. Interobserver reliability for LVMI was high (r = 0.94, p < 0.0007). LVMI decreased in 11 of 15 patients during dialysis and increased in 4. The mean difference in LVMI between pre- and posthemodialysis was 26.2 +/- 15 g/m2 (p < 0.0001). End-diastolic diameter decreased from 53.5 +/- 5.9 to 49.5 +/- 7.5 mm (p = 0.0016). These data indicate that measurement of LVMI is highly reproducible in hemodialysis patients but that it changes significantly over the course of a hemodialysis session. Its use as an outcome measure in clinical trials in hemodialysis patients should be interpreted with caution.

Quality of medical care during and shortly after acute care restructuring in Newfoundland and Labrador

Publisher Summary This chapter reviews seismological evidence and other geophysical evidence that the axial magma chamber beneath a fast spreading ridge is a narrow, thin, magma lens that lies at the sheeted-dike/gabbro cumulate transition region roughly 1.2–1.5 km beneath the seafloor and overlies a broader region of hot rock with at most ∼3–5% of partial melt fraction. This axial magma chamber appears to contradict earlier ophiolite-based studies that used the dip and dip relations within the cumulate gabbro layer to argue for a broad, gabbro-layer-thickness magma body that deposited cumulates along its base and sides. However, it is compatible with an emerging theoretical paradigm that crustal accretion occurs by magma emplacement and solidification within this magma lens, with cumulates subsiding and flowing to form the lower crust. The chapter presents a theoretical thermal and mechanical model for the crustal genesis that incorporates this paradigm and successfully explains the observed depth dependence of the axial magma lens with spreading rate (and the fact that no axial magma lens has been seen in a ridge with a median valley morphology), as well as observed relationships among axial morphology, spreading rate, and magma supply. The depth (and existence) of an axial magma lens and the axial morphology along a spreading center share a common thermal origin, which is a function of spreading rate and magma supply.

Congestive heart failure in dialysis patients: Prevalence, incidence, prognosis and risk factors

Objectives To critically evaluate the quality of hospital medical care at the beginning, during and shortly after regionalization of health boards in Newfoundland and Labrador, and aggregation of hospitals in the StJohns region. Methods Retrospective chart audits for the years 1995/96, 1998/99 and 2000/01 (at the beginning, during and after restructuring) focused on outcomes in cardiology, respiratory medicine, neurology, nephrology, psychiatry, surgery andwomens health programmes. Where possible, quality of care was judged on measurable outcomes in relation to published statements of likely optimal care. Comparisons were made over time within the StJohns region, and separately for hospitals in the rest of the province. Results There was improvement in the use of thrombolytics and secondary measures post-myocardial infarction in both regions. Mortality and appropriateness of initial antibiotic choice for community-acquired pneumonia remained stable in both regions, with an improvement in admission appropriateness based on the severity in St Johns. Aspects of stroke management (referral and time to see allied health professionals, imaging and discharge home) improved in both regions, while mortality remained stable. There was improvement in fistula rate, quality of dialysis and anaemia management in haemodialysis patients, and improvement in the peritoneal dialysis patient peritonitis rate. Readmission rate for schizophrenia remained unchanged. Stable mortality rates were observed for frequently performed surgical procedures. The post-coronaryartery by pass grafting (CABG) morbid event rate improved, although access to CABG was not optimal. Conclusions Aggregation of acute care hospitals was feasible without attendant deterioration in patient care, and in some areas care improved. However, access to services continued to be a major problem in all regions.