Ankle-brachial index: a simple way to predict mortality among patients on hemodialysis--a prospective study

The Prognostic Role of Serum β-Trace Protein Levels among Patients on Maintenance Hemodialysis

Cardiovascular (CV) diseases are the most commonly encountered etiology of mortality in patients having kidney failure. β-Trace protein (BTP) is a biomarker of glomerular filtration function as well as a potential predictor of adverse CV outcomes. This study aimed to determine the prognostic value of BTP in patients on chronic hemodialysis (HD). A total of 96 patients undergoing HD were enrolled. Baseline variables were collected, and the patients were tracked for 3 years. Twenty-five patients died at 3 years. Those who experienced mortality were noted to have higher serum concentrations of BTP and a higher incidence of diabetes mellitus (DM). The area under the receiver operating characteristic curve for serum BTP distinguishing mortality from survival was 0.659 (95% confidence interval [CI], 0.555-0.752; p = 0.027). After the adjustment of variables potentially affecting survival rates, BTP levels above the median (adjusted hazard ratio [aHR]: 2.913, 95% CI, 1.256-6.754; p = 0.013), the presence of DM (aHR: 2.474, 95% CI, 1.041-5.875; p = 0.040), and low serum albumin (aHR: 0.298, 95% CI, 0.110-0.806; p = 0.017) independently correlated with survival in HD patients. Serum BTP is a novel biomarker for predicting overall outcomes in HD patients.

Effects of a 16-week physical training on clinical outcomes in patients with hypertension and chronic kidney disease: NEPHROS post-trial follow-up

The NEPHROS is a randomized controlled trial which applied a 16-week aerobic and resistance training to patients with chronic kidney disease (CKD) and high blood pressure. This report describes a long-term post-trial follow-up, comparing survival, health-related quality of life (HRQoL), and estimated glomerular filtration rate (GFR) change between the intervention and control groups according to in-trial cardiovascular risk factors. Three years after the original trial, NEPHROS participants were re-evaluated. Cox proportional hazards model was used to compare survival time and linear regression for changes in GFR and physical and mental HRQoL summary scores between intervention and control groups according to age, sex, and in-trial GFR, C-reactive protein, glucose, lipids, ankle-brachial index (ABI), functional capacity, and blood pressure. Of the 150 participants of NEPHROS, 128 were included in the long-term analysis. The previous exercise training had no effects on survival, GFR, or HRQoL. Baseline in-trial GFR (HR = 0.95, 95%CI: 0.92; 0.98) and ABI (HR = 0.03, 95%CI: 0.002; 0.43) were positive independent predictors for survival. Lower ABI (coefficient = 9.00, 95%CI: 0.43; 17.5) and higher systolic blood pressure (coefficient = -0.13, 95%CI: -0.24; -0.03) were independent predictors for GFR decline. A 16-week exercise program had no long-term effect on survival, quality of life, or glomerular filtration in patients with CKD stages 2 to 4. Lower GFR and ABI and higher systolic blood pressure were associated with poorer prognosis among CKD patients.

Usefulness of Upstroke Time per Cardiac Cycle for Cardiovascular and All-Cause Mortality Prediction in Patients with Normal Ankle-Brachial Index

AIM

Abnormal ankle-brachial index (ABI) is regarded as peripheral artery disease and can be used to predict cardiovascular (CV) outcomes. However, the usefulness of ABI for the prediction of CV outcome in patients with normal ABI is limited. Upstroke time per cardiac cycle (UTCC) is recently reported to be associated with mortality in patients with acute myocardial infarction and the elderly. Therefore, we aimed to evaluate UTCC, left ventricular ejection fraction (LVEF), brachial-ankle pulse wave velocity (baPWV), and ABI for the prediction of mortality in patients with normal ABI.

METHODS

Patients arranged for echocardiographic examinations were enrolled, and 1076 patients with normal ABI were included. ABI, baPWV, and UTCC were measured by an ABI-form device.

RESULTS

The median follow-up to mortality was 95 months. There were 88 CV and 244 all-cause deaths. After multivariate analysis, UTCC was associated with increased CV and all-cause mortality (P ≤ 0.004). Age, diabetes, heart failure, left ventricular hypertrophy, baPWV, and LVEF were also independent predictors of CV and all-cause mortality, but ABI was not. Furthermore, UTCC had a better additive predictive value than ABI, baPWV, and LVEF for CV mortality ( P ≤ 0.012). It also had a better additive predictive value than ABI and LVEF for all-cause mortality (P ≤ 0.013).

CONCLUSIONS

UTCC is an independent predictor for CV and all-cause mortality in patients with normal ABI. It also has a better additive predictive value of CV and all-cause mortality than ABI and LVEF. Therefore, UTCC is a simple, novel, and useful parameter for identifying high-risk patients with normal ABI.

Inter-leg systolic blood pressure difference predicts cardiovascular events and mortality in incident hemodialysis patients

BACKGROUND

High inter-arm blood pressure difference, a marker of vascular disease, may be difficult to assess in hemodialysis patients with arm arteriovenous fistulae. We investigated if high inter-leg systolic blood pressure difference associates with cardiovascular events and increased mortality in hemodialysis patients.

METHODS

Among 118 incident Japanese dialysis patients, bilateral leg blood pressure, arm blood pressure, brachial-ankle pulse wave velocity, and ankle-brachial index were measured, and the relative risk associated with inter-leg systolic blood pressure difference and other indices of vascular status was analyzed.

RESULTS

During follow-up (median, 46 months), 18 deaths and 75 cardiovascular events occurred in 38 patients. Kaplan-Meier curves showed that higher inter-leg systolic blood pressure difference was associated with overall (log-rank 9.35, p = 0.002) and cardiovascular (log-rank 5.81, p = 0.02) mortality. The period from the start of dialysis therapy to the first cardiovascular event was shorter as inter-leg systolic blood pressure difference increased (log-rank 23.7, p < 0.0001). In Cox hazard models, inter-leg systolic blood pressure difference greater than median independently predicted deaths (relative risk, 3.8; 95% confidence interval, 1.3-13.9) and cardiovascular events (relative risk, 3.9; 95% confidence interval, 1.9-9.21) after adjustments for age, sex, nutritional status, and diabetes, whereas other indices were not related to the risks. For well-nourished, moderately malnourished, and severely malnourished patients, the cumulative number of cardiovascular events in the high-inter-leg systolic blood pressure difference patients were 4.96, 31.44, and 55.18 events per 100 patient-years.

CONCLUSIONS

Higher inter-leg systolic blood pressure difference associated with increased risk of mortality and cardiovascular events suggesting that wider application of inter-leg systolic blood pressure difference measurements may be warranted in hemodialysis patients.

Increased prevalence of peripheral arterial disease in patients with obese sarcopenia undergoing hemodialysis

Background peripheral arterial disease (PAD) is a common complication in patients undergoing dialysis, which reduces the quality of life and increases the risk of mortality. Recent literature has documented an association between increased visceral fat (VF) content and a proatherogenic factors in end-stage renal disease. The present study investigated the prevalence of PAD in patients undergoing hemodialysis. PAD was determined as an ankle-brachial index <0.9. Additionally, VF content was determined using multiple frequency bioelectrical impendence analysis. The nutritional status of the patients was evaluated by subjective global assessment and endothelial function was measured by ultrasonographic brachial artery flow-mediated dilatation. Patients divided into two groups (malnourished and non-malnourished) with two further subgroups in each (high VF and low VF content). The prevalence of PAD was identified to be significantly higher in patients with a high VF mass compared with a low VF mass in non-malnourished patients. PAD was significantly more common in malnourished patients compared with non-malnourished patients (P<0.01). The presence of PAD in patients undergoing hemodialysis was identified to be significantly correlated with age, diabetes mellitus (DM) status VF content, malnutrition, serum albumin level, diastolic blood pressure and log C-reactive protein levels. Furthermore, logistic regression analysis determined that age, DM, VF content and malnutrition were significant independent risk factors for PAD in patients undergoing hemodialysis. In conclusion, the results of the present study indicated that obesity and malnutrition act synergistically to increase the risk of PAD in patients undergoing dialysis.

Ankle-Brachial Index as a Predictor of Mortality in Hemodialysis: A 5-Year Cohort Study

Background

Abnormal ankle-brachial index (ABI) has been found to be a strong predictor of mortality in some hemodialysis populations in studies with relatively short periods of follow-up, lower than 2 years.

Objective

This study aimed to assess the predictive value of abnormal ABI as a risk factor for death among patients on maintenance hemodialysis after a 5-year follow-up.

Methods

A total of 478 patients on hemodialysis for at least 12 months were included in the study. ABI measurement was performed using a mercury column sphygmomanometer and portable Doppler. Patients were divided into 3 groups according to ABI (low: <0.9; normal: 0.9 to 1.3; and high: >1.3) and followed for a 60-month period.

Results

The prevalence rates of low, normal and high ABI were 26.8%, 64.6% and 8.6%, respectively. The 5-year survival rate was lower in the groups with low ABI (44.1%, P<0.0001) and high ABI (60.8%, P= 0.025) than in the group with normal ABI (71.7%). Cox regression was used to evaluate the association between ABI and mortality, adjusting for potential confounders. Using normal ABI as reference, a low, but not a high ABI was found to be an independent risk factor for all-cause mortality (HR2.57; 95% CI, 1.84-3.57 and HR 1.62; 95% CI, 0.93-2.83, respectively).

Conclusions

long-term survival rates of patients with either low or high ABI were lower than the one from those with normal ABI. However, after adjustment for potential confounders, only low ABI persisted as an independent risk factor for all-cause mortality among hemodialysis patients.

Predictive Factors of One-Year Mortality in a Cohort of Patients Undergoing Urgent-Start Hemodialysis

Background

Chronic kidney disease (CKD) affects 10–15% of adult population worldwide. Incident patients on hemodialysis, mainly those on urgent-start dialysis at the emergency room, have a high mortality risk, which may reflect the absence of nephrology care. A lack of data exists regarding the influence of baseline factors on the mortality of these patients. The aim of this study was to evaluate the clinical and laboratory characteristics of this population and identify risk factors that contribute to their mortality.

Patients and methods

We studied 424 patients who were admitted to our service between 01/2006 and 12/2012 and were followed for 1 year. We analyzed vascular access, risk factors linked to cardiovascular disease (CVD) and mineral and bone disease associated with CKD (CKD-MBD), and clinical events that occurred during the follow-up period. Factors that influenced patient survival were evaluated by Cox regression analysis.

Results

The patient mean age was 50 ± 18 years, and 58.7% of them were male. Hypertension was the main cause of primary CKD (31.8%). Major risk factors were smoking (19.6%), dyslipidemia (48.8%), and CVD (41%). Upon admission, most patients had no vascular access for hemodialysis (89.4%). Biochemical results showed that most patients were anemic with high C-reactive protein levels, hypocalcemia, hyperphosphatemia, elevated parathyroid hormone and decreased 25-hydroxy vitamin D. At the end of one year, 60 patients died (14.1%). These patients were significantly older, had a lower percentage of arteriovenous fistula in one year, and low levels of 25-hydroxy vitamin D.

Conclusions

The combined evaluation of clinical and biochemical parameters and risk factors revealed that the mortality in urgent-start dialysis is associated with older age and low levels of vitamin D deficiency. A lack of a permanent hemodialysis access after one year was also a risk factor for mortality in this population.

Peripheral artery disease and blood pressure profile abnormalities in hemodialysis patients

BACKGROUND

Patients undergoing chronic hemodialysis (HD) are at increased risk for peripheral artery disease (PAD). Both ankle-brachial index (ABI) and ambulatory blood pressure monitoring (ABPM) in the interdialytic period have been shown to be strong predictors of all-cause mortality.

METHODS

This cross-sectional study investigated the relationship between ABPM profile and ABI in 81 HD patients. ABPM was measured throughout a 44-h midweek interdialytic period. Pre-dialysis ABI was evaluated with a BOSO ABI device. An ABI value <0.9 or ≥1.3 was defined as abnormal.

RESULTS

In the whole study group (72 % males, mean age 67 ± 14 years), there was an increase in BP (p < 0.05) and in systolic BP night/day ratio (n/dSR, p = 0.01) during the interdialytic period. Patients with abnormal ABI (n = 29) more frequently had a positive history for cerebrovascular accident and PAD and higher proBNP values than those with normal ABI (n = 52). No difference was detected among ABPM-derived components except for the n/dSR (p = 0.02). Patients with abnormal ABI showed a significantly increased n/dSR (p = 0.02) and ambulatory arterial stiffness index (AASI) (p = 0.006) on the second day compared to the first. Patients with n/dSR >1 during day 2 (n = 34) were older, showed significantly higher proBNP and AASI and were more likely to reveal abnormal ABI compared to those with a lower n/dSR (p = 0.006).

CONCLUSIONS

Abnormal ABI in HD patients is associated to changes in interdialytic ABPM pattern, namely higher n/dSR on day 2. These data may indicate the pathophysiological mechanisms underlying the worse outcome observed in HD patients.

Coronary Artery Calcification Seen Through Chest Radiography

Patients with end-stage renal disease (ESRD) on dialysis have poor overall survival, and cardiovascular (CV) is the main cause of mortality among these patients. Coronary calcification is an independent predictor of mortality and CV events in dialysis patients and can be accessed by using a computerized tomography scanning. The high cost of this procedure, however, precludes routine implementation of this method for the purposes of risk stratification. Aortic arch calcification has been associated with CV mortality in the general population. Also, vascular calcification beyond the thoracic aorta has been shown to be associated with mortality in ESRD patients. We presented here a case of a young patient with ESRD in which the coronary calcification could be cleared seen through simple chest radiography. This is a 35-year-old man with a history of ESRD secondary to pyelonephritis, who was receiving conventional hemodialysis thrice a week for the last 5 years. He was submitted to chest radiography as part of routine annual cardiac screening. His blood pressure was within the target limits, although much higher in lower limbs, generating a high ankle brachial index of 1.3. He also had secondary hyperparathyroidism. His physical examination was unremarkable, except for the presence of non-functioning arteriovenous fistulas in both arms and a central venous catheter. The last routine blood test showed calcium 9.0 mg/dL, phosphate 5.7 mg/dL, potassium 4.7 mEq/L, creatinine 7.4 mg/dL, alkaline phosphatase 175 U/L, and parathyroid hormone 1,745 pg/mL. Surprisingly, the chest radiography revealed a calcified aortic valve and a calcified coronary artery. This patient had sudden cardiac death few months after this radiography had been taken. We present here a case of coronary calcification that can be seen through simple chest radiography. Such images are not usually seen, although the risk of vascular calcification is high in this population, and is closely related to CV risk. Chest radiographs, nearly universally available provide a method for assessing coronary artery calcification. Such a finding is intriguing and should alert nephrologists and cardiologists for the high risk of CV death in these patients.

Sites of peripheral artery occlusive disease as a predictor for all-cause and cardiovascular mortality in chronic hemodialysis

Background

The ankle—brachial blood pressure (BP) index (ABI) not only indicates the presence of peripheral artery occlusive disease (PAOD) but predicts mortality in patients undergoing hemodialysis (HD). However, whether the site of PAOD can provide additional contribution to predicting mortality have not been investigated yet. Our primary objective was to determine the associations between the site of PAOD and all-cause and cardiovascular mortality in chronic HD (CHD) patients.

Methods

A retrospective cohort study was conducted to evaluate 444 Taiwanese CHD patients between December 2006 and June 2013. The site of PAOD together with other explanatory variables such as demographic data, body mass index, a history of cardiovascular diseases, HD vintage, biochemical data, and cardiothoracic ratio (CTR) were assessed by the Cox proportional hazards regression model.

Results

The frequency of PAOD was 14.6% in both legs, 4.9% in the right side only, and 5.1% in the left side only. During the study period, 127 all-cause and 93 cardiovascular deaths occurred. PAOD site was found to have significant predictive power for all-cause mortality with the order of 3.04 (95% CI: 1.56–5.90) hazard ratio on the right side, 2.48 (95% CI: 1.27–4.82) on the left side, and 4.11 (95% CI: 2.76–6.13) on both sides. The corresponding figures for cardiovascular mortality were 3.81 (95% CI: 1.87–7.76) on the right side, 2.76 (95% CI: 1.30–5.82) on the left side, and 3.95 (95% CI: 2.45–6.36) on both sides. After adjustment for other explanatory variables, only right-sided PAOD still remained to have significant predictive power for all-cause and cardiovascular mortality and bilateral PAOD kept the significant association with all-cause mortality.

Conclusions

The site of PAOD revealed various predictive powers for all-cause and cardiovascular mortality in CHD patients and only right-sided PAOD remained an independent predictor for both types of mortality making allowance for relevant confounding factors.

Observational multicenter study to evaluate the prevalence and prognosis of subclinical atheromatosis in a Spanish chronic kidney disease cohort: baseline data from the NEFRONA study

BACKGROUND

Cardiovascular events (CVE) are more prevalent in chronic kidney disease (CKD) than in general population, being the main cause of morbimortality. Specific risk factors related to CKD have been suggested, because traditional factors do not fully explain this increase in cardiovascular disease rates. However, the role of atheromatosis, its pathogenesis and evolution are still unclear. The potential use of diagnostic tests to detect subclinical atheromatosis has to be determined.

METHODS

NEFRONA is a prospective multicenter cohort study. 2445 CKD subjects were enrolled from 81 Spanish hospitals and dialysis clinics, from 2010 to 2012. Eligibility criteria included: 18 to 74 years old, CKD stage 3 or higher, and no previous CVE. 559 non-CKD controls were also recruited. Demographical, clinical and analytical data were collected. Carotid and femoral ultrasounds were performed by a single trained team to measure carotid intima-media thickness (cIMT) and detect atheromatous plaques. Ankle-brachial index (ABI) was measured.

RESULTS

Differences in age, sex and prevalence and control of cardiovascular risk factors were found between controls and CKD patients. These differences are similar to those described in epidemiological studies.No difference was found regarding cIMT between controls and CKD (when subjects with plaques in common carotid arteries were omitted); earlier CKD stages had higher values. CKD patients had a higher rate of atheromatous plaques, with no difference between stages in the unadjusted analysis. A group of patients had plaques in femoral arteries but were plaque-free in carotid arteries, and would have gone underdiagnosed without the femoral study. The percentage of pathologic ABI was higher in CKD, with higher prevalence in more advanced stages, and a higher rate of ABI >1.4 than <0.9, suggesting more vascular calcification.

CONCLUSIONS

NEFRONA is the first large study describing the actual prevalence of subclinical atheromatosis across different CKD stages. There is a very high rate of atheromatous plaques and pathologic ABI in CKD. Prospective data will add important information to the pathogenesis and evolution of atheromatosis in CKD, compared to non-CKD subjects.