Biomedical subjects

Irene Ma

Publications and source records attributed to Irene Ma.

4 recordsLinked to original sources

PubMed2005

Kidney function and mortality among patients with left ventricular systolic dysfunction.

Kidney disease has emerged as a risk factor for mortality in heart failure populations. The objective of this study was to determine the impact of different stages of kidney dysfunction (defined using the Kidney Disease Outcomes Quality Initiative [K/DOQI] classification system) and changes in kidney function on mortality in a cohort of patients with heart failure. A retrospective analysis was conducted of data from the randomized controlled trials Studies of Left Ventricular Dysfunction. A total of 6640 participants with asymptomatic and symptomatic heart failure were studied. Estimated GFR (eGFR) were calculated and then categorized according to the K/DOQI classification system into the following categories: > or =90, 60 to 89, 30 to 59, and 15 to 29 ml/min per 1.73 m2. Reduction in eGFR from baseline was calculated and subsequently categorized according to rate of decline (<5, 5 to 10, 11 to 15, and >15 ml/min per 1.73 m2 per year). Independent of baseline differences, lower levels of eGFR were associated with a higher total mortality compared with those with eGFR > or =90 ml/min (30 to 59 ml/min per 1.73 m2: hazard ratio [HR] 1.32, 95% confidence interval [CI] 1.10 to 1.59, P = 0.004; 15 to 29 ml/min per 1.73 m2: HR 2.54, 95% CI 1.54 to 4.19, P < 0.001). eGFR deteriorated rapidly (>15 ml/min per 1.73 m2 per year) in 12% of participants. This decline was associated with a significant increase in mortality compared with slower decline (<5 ml/min per 1.73 m2 per year), despite adjustments for baseline kidney function, baseline heart failure, or change in heart failure (HR 5.63; 95% CI 4.90 to 6.46; P < 0.0001). The levels of eGFR from the K/DOQI classification system are associated with mortality in a well-characterized heart failure population. Rate of decline in kidney function is a strong predictor of increased mortality in this population, independent of worsening heart failure and baseline kidney function.

Adult↗

PubMed2005

Cardiovascular events and investigation in patients who are awaiting cadaveric kidney transplantation.

The optimal strategy for cardiovascular (CV) disease surveillance in kidney transplant candidates is uncertain. In this observational study of 604 wait-listed patients in British Columbia, the risk for CV event in diabetic and nondiabetic candidates was 12.7 and 4.5% per year, respectively. CV event rates were relatively constant during the first 3 yr of wait-listing (5.3 to 6.6 per 100 patient-years; 95% confidence interval [CI], 3.7 to 9.3) but rose dramatically during the peritransplantation period (39.6/100 patient-years; 95% CI, 20.6 to 76.1) and remained high throughout the first posttransplantation year (4.0 per 100 patient-years; 95% CI, 2.2 to 7.5). The results of noninvasive cardiac investigations before wait-listing were not predictive of the time to CV event after wait-listing. The practice of surveillance cardiac investigation in wait-listed patients on the basis of ongoing clinical assessment of cardiac risk resulted in fewer investigations (n = 171) than with the recommended practice of periodic screening on the basis of waiting time alone (n = 530) and was not associated with an increased frequency of CV events (CV event rate in patients with and without the recommended frequency of investigation was 9.9 [95% CI, 7.1 to 13.7] and 6.7 [95% CI, 5.2 to 8.7] per 100 patient-years). It is concluded that transplant candidates are at high risk for CV events particularly during the perioperative period. Initial cardiac investigations have limited value in guiding the timing of patient reevaluation after wait-listing. Periodic surveillance cardiac investigation after wait-listing may be unnecessary and requires further study.

Adult↗

PubMed2003

Determinants of glomerular hypofiltration in aging humans.

BACKGROUND: The purpose of the present study was to confirm the extent to which glomerular filtration rate (GFR) is depressed in healthy, aging subjects and to elucidate the mechanism of such hypofiltration. METHODS: Healthy volunteers aged 18 to 88 years (N = 159) underwent a determination of GFR, renal plasma flow (RPF), afferent oncotic pressure, and arterial pressure. Glomeruli in renal biopsies of healthy kidney transplant donors aged 23 to 69 years (N = 33) were subjected to a morphometric analysis, so as to determine glomerular hydraulic permeability and filtration surface area. The aforementioned GFR determinants were then subjected to mathematical modeling to compute the glomerular ultrafiltration coefficient (Kf) for two kidneys and individual glomeruli. RESULTS: GFR was significantly depressed (P < 0.0001) by 22% in aging (>or=55 years old) compared to youthful subjects (<or=40 years old). Corresponding reductions of the following GFR determinants in the aging vs. youthful subsets were RPF by 28% (P < 0.0001), two-kidney Kf by 21% to 53% (P < 0.005), glomerular hydraulic permeability by 14% (P = 0.03), and the single-nephron Kf (SNKf) by 30% (P = 0.09). There were no significant differences between aging and youthful subsets for afferent oncotic pressure and filtration surface area per glomerulus. CONCLUSION: We conclude that a reduction in overall, two-kidney Kf contributes to GFR depression in aging subjects. We infer that this is due in part to structural changes that lower SNKf, and in part to the reduction in the actual number of functioning glomeruli that has been demonstrated by others at autopsy.

Adult↗

PubMedDate not supplied

Nosocomial MRSA infection in vascular surgery patients: impact on patient outcome.

Although methicillin-resistant Staphylococcus aureus (MRSA) infection is a worldwide problem, data on its significance among vascular surgery patients remain scant and conflicting. This study was designed to evaluate the association between nosocomial MRSA infection and patient outcome following vascular surgery procedures. Outcomes among patients with MRSA infection were also compared to those infected with methicillin-sensitive Staphylococcus aureus (MSSA). All patients admitted to a tertiary care Vascular Surgery ward during the year 2002 were included in this retrospective review. In addition to information on demographic and comorbid conditions, data on surgical interventions, nosocomial infection incidence rates as defined by the Center for Disease Control guidelines, and MRSA screening results were collected. Primary outcome was in-hospital death. Secondary outcomes measures included length of hospital stay, readmissions, or repeat surgeries, and ICU admissions. Of a total of 408 subjects, 110 were documented with a nosocomial infection (27.0%). Of these, 16 patients (3.9%) were colonized with MRSA on screening at time of admission, 22 (5.4%) had acquired MRSA infection during hospitalization, and 15 (3.7%) had MSSA infection. Patients with MRSA, MSSA, and non-MRSA infection had similar baseline characteristics except for hypertension and tobacco use. Age and MRSA infection were significant risk factors for in-hospital deaths (OR 1.07, 95% CI 1.01-1.13, p = 0.01 and OR 7.44, 95% CI 1.63-33.9, p = 0.01, respectively). Adjusted for the effects of age, MRSA infection remained a significant independent risk factor associated with in-hospital deaths (OR 4.38, 95% CI 1.09-17.7, p = 0.04). After adjustment for baseline risk factors, MRSA infection was also independently associated with secondary outcome measures. Although risks of non-MRSA infections were also associated with adverse outcomes in the multivariate analyses, MRSA posed higher risks, as reflected by higher odds ratio in all instances. The 22 patients with documented MRSA infection had significantly longer hospital stays than those with MSSA infection (median 24 days vs 8 days, p = 0.02). However, no significant differences were noted between the 2 groups in terms of secondary outcome. These results show that MRSA infection is a significant risk factor for adverse clinical outcomes among patients undergoing vascular surgery procedures. Infection with MRSA results in a greater risk of these outcomes when compared with non-MRSA infection. However, despite concerns regarding the virulence of this strain of staphylococcus, patients infected with MRSA had no higher rates of morbidity or mortality except for increased length of hospital stay when compared to patients with MSSA.

Aged↗