Increasing prevalence of peripheral artery occlusive disease in hemodialysis patients: a 2-year follow-up

Ca2+ Influx through TRPC Channels Is Regulated by Homocysteine-Copper Complexes

An elevated level of circulating homocysteine (Hcy) has been regarded as an independent risk factor for cardiovascular disease; however, the clinical benefit of Hcy lowering-therapy is not satisfying. To explore potential unrevealed mechanisms, we investigated the roles of Ca²⁺ influx through TRPC channels and regulation by Hcy-copper complexes. Using primary cultured human aortic endothelial cells and HEK-293 T-REx cells with inducible TRPC gene expression, we found that Hcy increased the Ca²⁺ influx in vascular endothelial cells through the activation of TRPC4 and TRPC5. The activity of TRPC4 and TRPC5 was regulated by extracellular divalent copper (Cu²⁺) and Hcy. Hcy prevented channel activation by divalent copper, but monovalent copper (Cu⁺) had no effect on the TRPC channels. The glutamic acids (E542/E543) and the cysteine residue (C554) in the extracellular pore region of the TRPC4 channel mediated the effect of Hcy-copper complexes. The interaction of Hcy-copper significantly regulated endothelial proliferation, migration, and angiogenesis. Our results suggest that Hcy-copper complexes function as a new pair of endogenous regulators for TRPC channel activity. This finding gives a new understanding of the pathogenesis of hyperhomocysteinemia and may explain the unsatisfying clinical outcome of Hcy-lowering therapy and the potential benefit of copper-chelating therapy.

Association between systemic sclerosis and peripheral arterial disease: a nationwide observation retrospective claim records cohort study in Taiwan

OBJECTIVES

Recent studies have proposed associations between systemic sclerosis (SSc) and atherosclerosis and between SSc and cardiovascular disease. However, in Asia, no large-scale studies have focused on the association between peripheral arterial disease (PAD) and SSc.

SETTING

A nationwide observation retrospective cohort study.

PARTICIPANTS

The National Health Insurance Research Database was used for selecting patients diagnosed with SSc from 2000 to 2011. Patients diagnosed with PAD before the index date were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

The SSc cohort comprised 1106 patients with SSc, and the non-SSc cohort comprised 4424 matched controls. The Cox proportional hazards regression model was used for analysing the adjusted risk of PAD between the case and control patients.

RESULTS

The SSc cohort exhibited a significantly higher risk (HR=2.15, 95% CI=1.47 to 3.14) of PAD than did the non-SSc cohort. Patients with heart failure exhibited the highest risk of PAD (adjusted HR=2.10, 95% CI=1.20 to 3.70). Moreover, even without any comorbidities, the SSc cohort exhibited a significantly higher risk (adjusted HR=4.17 fold, 95% CI=1.98 to 8.77) of PAD than did the non-SSc cohort.

CONCLUSION

SSc is associated with a significantly high risk of PAD. Further studies are required to reduce the PAD risk among patients with SSc.

Increased risk of developing peripheral artery disease in hemodialysis patients receiving statin treatments: a population-based cohort study in Taiwan

Background

Few investigations have evaluated the influences on peripheral arterial disease (PAD) risk of statin treatment in hemodialysis (HD) subjects with hyperlipidemia (HL).

Methods

From the National Health Insurance Research Dataset, we identified 3658 HD patients with statin therapy for HL as the statin cohort, and then selected, by 1:1 propensity score matching, 3658 HD patients with HL but without statin use as the nonstatin cohort in 2000–07. The cohorts were followed through until the end of 2011. We used Cox proportional hazards regression analysis to assess the hazard ratio (HR) of PAD development.

Results

The average follow-up period was 4.18 years; the incident PAD risk was 1.35-fold greater in statin users than in nonusers (16.87 versus 12.46/1000 person-years), with an adjusted HR (aHR) of 1.34 for PAD [95% confidence interval (CI) 1.12–1.62]. The PAD risk increases were significant for patients receiving fluvastatin (aHR 1.88; 95% CI 1.12–3.14) and atorvastatin (aHR 1.60; 95% CI 1.24–2.08). The risk increased with higher annual average statin dosage (P for trend <0.0001); the risk was higher for those receiving moderate-intensity statin treatment. The sensitivity test revealed similar findings.

Conclusions

HD patients with HL on statin medication were at increased PAD risk, which increased with cumulative statin dosage. Thorough considerations are needed before prescribing statins to HD patients.

Association of Pulse Volume Recording at Ankle with Total and Cardiovascular Mortality in Hemodialysis Patients

Pulse volume recording is an accurate modality for detecting arterial occlusion in the lower extremities. There are two indexes of pulse volume recording measured at ankle, percentage of mean arterial pressure (%MAP) and upstroke time (UT). The aim of the study was to examine the ability of %MAP and UT for the prediction of overall and cardiovascular mortality in hemodialysis (HD) patients. In 197 routine HD patients, ankle %MAP, ankle UT, and ankle-brachial index (ABI) were automatically measured by Colin VP-1000 instrument. Fourteen cardiovascular mortality and 29 overall mortalities were documented during 2.7 ± 0.6 years follow-up. In the univariate analysis, in addition to co-morbidities and traditional clinical parameters, increased total mortality was associated with decreased ABI, ABI < 0.9, increased %MAP and UT, %MAP > 50%, and UT > 169 ms (p < 0.041) and increased cardiovascular mortality was associated with increased UT and %MAP > 50% (p < 0.022). After multivariate analysis, increased %MAP and %MAP > 50% (p < 0.047) were still the predictors of total mortality and %MAP > 50% (p = 0.024) was still the predictor of cardiovascular mortality. In HD patients, we found that ankle %MAP and %MAP > 50% could predict total mortality and ankle %MAP > 50% could predict cardiovascular mortality in the multivariate analysis. Hence, assessment of %MAP from pulse volume recording at ankle might be helpful in identifying the high-risk group for poor prognosis in HD 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.

Peripheral Arterial Disease and Spinal Cord Injury: A Retrospective Nationwide Cohort Study

The aim of this study was to elucidate the relationship between spinal cord injury (SCI) and the risk of peripheral arterial disease (PAD) in a cohort study with a large representative sample.The National Health Insurance Database was used to select patients who were diagnosed from 2000 to 2010. Patients with a history of PAD were excluded. The SCI group comprised 42,673 patients diagnosed with SCI, and we enrolled 170,389 matched controls (non-SCI group). We used a Cox proportional hazards regression model to analyze the adjusted risk of PAD between the case and control patients.Patients with SCI exhibited a significantly higher risk (hazard ratio [HR] = 1.37; 95% confidence interval [CI] = 1.22-1.53) of PAD than patients without SCI. Patients with diabetes were at the highest risk of developing PAD (adjusted HR = 3.11, 95% CI = 2.80-3.44). Among patients without comorbidity, SCI patients exhibited a significantly higher risk of PAD than non-SCI patients. Furthermore, lumbar, sacral, or coccygeal spine, and multiple spine SCI were significantly associated with an increased risk of PAD (HR = 1.56, 95% CI = 1.33-1.84, HR = 2.11, 95% CI = 1.59-2.79, respectively).SCI is associated with an increased risk of PAD. Future studies should focus on modifying risk factors to reduce PAD risk among patients with SCI.

Hemodialysis Is Associated With Increased Peripheral Artery Occlusive Disease Risk Among Patients With End-Stage Renal Disease: A Nationwide Population-Based Cohort Study

To investigate the effect of different dialysis modalities on the incidence of peripheral artery occlusive disease (PAOD) among patients with end-stage renal disease (ESRD) in a large population-based cohort study. The cohort study included 26,927 ESRD patients who underwent hemodialysis (17,737 patients, hemodialysis [HD] cohort) or peritoneal dialysis (PD, 9190 patients, PD cohort), and 107,588 matched controls between 2000 and 2010. A Cox proportional hazards model was to evaluate the risk of PAOD in the ESRD underwent HD or PD. Based on a mean follow-up period of 2.92, 3.64, and 4.91 years in the PD, HD, and control cohorts, respectively, the incidences of PAOD were 18.1% and 8.10% higher in the HD and PD cohorts, respectively, compared with the control cohort (log-rank test P < 0.001). The patients who underwent HD or PD exhibited a higher risk of PAOD compared with the control cohort regardless of age, sex, and presence or absence of comorbidities. In addition, the incidence of PAOD in the PD cohort and the propensity score-matched HD cohort were 12.4 and 20.7 per 1000 person-years, respectively, with a hazard ratio of 1.92 (95% confidence interval = 1.62-2.28) in HD patients, compared with the PD cohort. This nationwide population-based cohort study suggested a significantly increased risk of PAOD among ESRD patients. Moreover, the PD patients have a lower risk of developing PAOD compared with the HD cohort, indicating the beneficial roles of PD in reducing PAOD risk in ESRD patients.

Invasively-treated incidence of lower extremity peripheral arterial disease and associated factors in Taiwan: 2000-2011 nationwide hospitalized data analysis

BACKGROUND

Lower extremity (LE) peripheral artery disease (PAD), which is associated with a reduced quality of life and increased mortality from atherosclerotic cardio-/cerebro-vascular occlusion, is a significant public health problem, especial for an aging society such as that of Taiwan.

METHODS

Specific datasets of the 2000-2011 nationwide inpatient databases were analyzed. Two inclusion criteria, including one of the major diagnosis codes of PAD and one of three categorical invasive treatments of LE PAD, were used consecutively to select cases diagnosed as LE PAD and receiving invasive treatment. The epidemiology of invasively-treated PAD in Taiwan was estimated, and the influences of potential confounders on these invasively-treated methods were evaluated.

RESULTS

In general, the invasively-treated incidence of PAD in Taiwan doubled, from 3.73/10,000 (in 2000) to 7.48/10,000 (in 2011). On average, the total direct medical cost of one hospitalized and invasively-treated PAD case ranged from $US 4,600 to $US 5,900. The annual cases of bypass surgery for the PAD cases averaged 1,000 and the cases for limb amputation ranged from 4,100 to 5,100 annually. However, the number of percutaneous transluminal angioplasty (PTA) procedures remarkably increased by 15 times, from 600/year to 9,100/year, from 2000 to 2011. 51.3% of all the enrolled cases were treated with limb amputations, and female, young and middle-aged people (30-65 years of age), DM patients and those on a low income had a tendency to undergo amputation due to PAD. 37.6% of all the enrolled cases were treated with PTAs related to hypertension, cardiovascular disease, hyperlipidemia and catastrophic Illness. 2-year PTA failure rates of 22.13%, 11.91% and 10.61% were noted among the first (2000-2001), second (2004-2005) and the third (2008-2009) cohort groups, respectively.

CONCLUSIONS

In Taiwan, a gender difference and age and period effects on the invasively-treated incidence of LE PAD were observed. Female, young and middle-aged people (30-50 and 50-65 years of age), DM patients and those on a low income had a tendency to undergo amputation. The number of PTA procedures remarkably increased, but the 2-year failure rate of PTAs reduced from 2000 to 2011.

Prevalence of Asymptomatic Peripheral Arterial Disease and Related Risk Factors in Younger and Elderly Patients in Taiwan

We determined the prevalence of asymptomatic peripheral arterial disease (PAD) and cardiovascular risk factors in Taiwan. Ambulatory participants (n = 1915) without symptoms of PAD were enrolled (mean age of 61.2 years). The ankle-brachial index (ABI) was used to detect the PAD (ABI < 0.90). The overall prevalence of asymptomatic PAD was 5.4% (2.8% in the younger participants [<65 years of age, n = 1021] and 8.4% in the elderly participants [≥65 years of age, n = 894]). Younger participants with asymptomatic PAD had a significantly higher rate of hypertension (55.2% vs 30%) and obesity (31% vs 13.3%) than those without asymptomatic PAD ( P < .05). Elderly participants with asymptomatic PAD had a significantly higher rate of diabetes mellitus (36% vs 21.2%) and hypertension (69.3% vs 55.4%) than those without asymptomatic PAD ( P < .05). Asymptomatic PAD is prevalent among elderly Taiwanese individuals. Overall, age was the strongest risk factor for the development of asymptomatic PAD.

Decrease in ankle-brachial index over time and cardiovascular outcomes in patients with hemodialysis

INTRODUCTION

Abnormal ankle-brachial index (ABI) is associated with increased morbidity and mortality in hemodialysis patients. However, whether the decrease in ABI over time carries the prognostic value is unknown. The aim of this study was to assess whether the decrease in ABI over time was a good predictor of poor cardiovascular (CV) prognosis in hemodialysis patients.

METHODS

This study enrolled 234 routine hemodialysis patients and 173 patients completed the follow-up. The ABI was measured by an ABI-form device at baseline and at the first year follow-up. The ΔABI was defined as ABI measured at the first year follow-up minus ABI measured at baseline. Progressors of ABI were defined as patients with ΔABI < -0.3. CV events were defined as CV death, hospitalization for unstable angina, nonfatal myocardial infarction, hospitalization for arrhythmia, hospitalization for congestive heart failure and stroke.

RESULTS

The follow-up period was 37.8 ± 11.1 months. In the multivariate analysis, progressors of ABI (hazard ratio, 2.71; 95% confidence interval, 1.10-6.68, P = 0.03), decreased albumin and increased high-sensitivity C-reactive protein were associated with increased CV events.

CONCLUSIONS

This longitudinal study showed ΔABI < -0.3 was independently associated with an increase in CV events. Hence, a great decrease in ABI over time might be a useful indicator of poor CV prognosis in hemodialysis patients.