Li-Jun Tang

Peking University Third Hospital, Peping, Beijing, China

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Publications (10)21.04 Total impact

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    ABSTRACT: In this study, we focused on whether volume overload plays a role in the development of arterial stiffness. Seventy-three prevalent hemodialysis patients were enrolled in a cross-sectional study. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (PWV), and volume overload was assessed by bioimpedance analysis. Patients were divided into a high PWV group and a low PWV group based on the median of PWV. Age, systolic blood pressure, pulse pressure (PP), extracellular water/total body water ratio (ECW/TBW), diabetic status (all p < 0.01), and history of cardiac events (p < 0.05) were significantly higher in the high PWV group (n = 37) than in the low PWV group. In the correlation analysis, PWV was positively associated with PP, systolic blood pressure, ECW/TBW, age, history of cardiac events, and diabetes (all p < 0.01). Multiple regression analysis showed that PWV was independently related to PP and ECW/TBW (p < 0.01). Volume overload plays an important role in the development of arterial stiffness in hemodialysis patients.
    Blood Purification 02/2009; 27(3):248-52. · 2.06 Impact Factor
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    ABSTRACT: While a high blood pressure (BP) in patients receiving maintenance ambulatory peritoneal dialysis (CAPD) is associated with congestive heart failure and an increased mortality, the relevance of diurnal variations in BP is unknown. In a prospective study, we enrolled 76 prevalent patients receiving stable CAPD (age 60.4 +/- 13.8 years; 37 males). BP was measured over 24 h using an automated device. We also performed routine clinical and biochemical measurements, as well as the Karnofsky index to evaluate physical activity. Volume status was assessed using bioimpedance analysis. 69 patients (with an average time on dialysis of 24.4 +/- 22.5 months) completed the study. Of these, 16 patients experienced a drop in BP >10% at night (dippers), while 53 patients did not (non-dippers). Comparing these two groups, dippers had significantly lower extracellular water (ECW) (13.8 +/- 2.1 vs. 15.9 +/- 3.3 l; p < 0.05), normalized extracellular water (nECW) (0.22 +/- 0.05 vs. 0.26 +/- 0.04 l/m; p < 0.05), and serum albumin (38.2 +/- 2.9 vs. 35.9 +/- 3.7 g/l; p < 0.05). Age, Karnofsky index, vintage, residual renal Kt/V and peritoneal Kt/V, total Kt/V, dose of antihypertensive drugs, mean systolic and diastolic BP did not significantly differ between these groups. Correlation analysis showed the coefficient of variation (CV) of BP positively correlated with E/T (r(2) = 0.292; p < 0.05), diabetic (r(2) = 0.267; p < 0.05), male (r(2) = 0.257; p < 0.05), nECW (r(2) = 0.278; p < 0.05) and ECW (r(2) = 0.249; p < 0.05) negatively correlated with albumin (r(2) = -0.280; p < 0.05). Furthermore, in a multivariate linear regression model, E/T, albumin and sex were independently associated with CV for BP. We show that reduced BP variation is common in CAPD patients and associated with volume overload and hypoalbuminemia. Furthermore, the relationship between nutritional, inflammatory status and dipping needs further studies.
    Blood Purification 08/2008; 26(5):399-403. · 2.06 Impact Factor
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    ABSTRACT: While cardiovascular disease accounts for 40-50% of the mortality in dialysis patients, and while a high peritoneal transport in continuous ambulatory peritoneal dialysis (CAPD) is an independent predictor of outcome, it is unclear if there are any links. Aortic stiffness has become established as a cardiovascular risk factor. We thus studied pulse wave velocity (PWV) in CAPD patients to explore the possible link between peritoneal small solute transport and aortic stiffness. CAPD patients (n = 76, 27 M/49 F) in our center were included in the present study. Aortic stiffness was assessed by brachial pulse pressure (PP) and carotid-femoral PWV. Patients' peritoneal small solute transport rate was assessed by D/P(cr) at 4 h. Extracellular water over total body water (E/T ratio) was assessed by means of bioimpedance analysis. C-reactive protein was also measured. Carotid-femoral PWV was positively associated with patients' age (r = 0.555; P < 0.01), time on peritoneal dialysis (r = 0.332; P < 0.01), diabetic status (r = 0.319; P < 0.01), D/P(cr) (r = 0.241; P < 0.05), PP (r = 0.475; P < 0.01), and E/T (r = 0.606; P < 0.01). In a multivariate regression analysis, carotid-femoral PWV was independently determined by E/T (P < 0.01), PP (P < 0.01), age (P < 0.01), and D/P(cr) (P < 0.05). D/P(cr), in addition to E/T, age, and PP, was an independent predictor of elevated carotid-femoral PWV in CAPD patients, suggesting that there might be a link between high aortic stiffness and increased peritoneal small solute transport rate.
    Artificial Organs 06/2008; 32(5):416-9. · 1.96 Impact Factor
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    ABSTRACT: Malnutrition is a predictor of cardiovascular disease in dialysis patients, but the mechanisms remain unknown. We investigated links between nutritional markers and arterial stiffness in continuous ambulatory peritoneal dialysis patients. We evaluated the relationship between arterial stiffness evaluated by pulse-wave velocity (PWV) and four estimates of nutritional status (serum albumin, handgrip strength [HGS], subjective global assessment [SGA], and bioelectrical impedance analysis phase angle [PA]) in 124 PD patients. Malnourished patients exhibited a significantly higher PWV than those classified as well-nourished by SGA (p < 0.05). Furthermore, PWV correlated negatively with albumin, HGS and PA (p < 0.001, respectively). PWV was also correlated with age, systolic blood pressure, and C-reactive protein. In multivariate regression analysis, albumin, HGS, SGA and PA were each independently associated with PWV after adjustment. The significant association between each nutritional marker and PWV in PD patients was independent of inflammation and diabetic state, suggesting that malnutrition may contribute to vascular dysfunction.
    Blood Purification 05/2008; 26(4):340-6. · 2.06 Impact Factor
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    ABSTRACT: The aim of this study was to validate whether differences in aortic stiffness are responsible for the differences in cardiovascular mortality among hypertension subtypes. Twenty hundred and fifty continuous ambulatory peritoneal dialysis patients were included in the present study. They were classified into four groups: normotensives (n=92) with systolic blood pressure (SBP) <140 mmHg and diastolic blood pressure (DBP) <90 mmHg; isolated systolic hypertensives (ISH, n=84) with SBP > or =140 mmHg and DBP <90 mmHg; isolated diastolic hypertensives (IDH, n=21) with SBP <140 mmHg and DBP > or =90 mmHg; and systolic-diastolic hypertensives (SDH, n=53) with SBP > or =140 mmHg and DBP > or =90 mmHg. Aortic stiffness was assessed by pulse pressure, central pressure parameters and pulse wave velocity. The IDH group had more male patients and a lower mean age than the other groups. The percentage of diabetes in the ISH group was higher than that in the other groups. The comparisons of aortic stiffness showed that the ISH and SDH groups had higher aortic stiffness than the normotension and IDH groups. The aortic stiffness in the ISH group was also higher than that in the SDH group, but there was no significant difference in aortic stiffness between the normotension and IDH groups. In conclusion, this study showed that aortic stiffness was significantly different among different hypertension subtypes, which might be an underlying cause of the differences in cardiovascular mortality among the hypertension subtypes.
    Hypertension Research 04/2008; 31(4):593-9. · 2.79 Impact Factor
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    ABSTRACT: A high peritoneal transport status in continuous ambulatory peritoneal dialysis (CAPD) patients is associated with a markedly increased morbidity and mortality. While the causes are as yet unknown, overall the proportion of deaths due to cardiovascular disease is estimated at 40-50% among dialysis patients. Arterial stiffness has been established as a cardiovascular risk factor, while the links between peritoneal transport status and aortic stiffness have not yet been investigated. We included 65 prevalent CAPD patients (24 males/41 females) from our center in a cross-sectional study. Arterial stiffness was assessed by brachial pulse pressure (PP) and carotid-femoral pulse wave velocity (C-F PWV). The patients' peritoneal fluid transport was assessed by kinetic modeling. The patients' peritoneal small solute transport rate was assessed by D/P(cr) at 4 h. Extracellular water to total body water (E/T) ratio was assessed by means of bioimpedance analysis. C-reactive protein was also measured. C-F PWV was positively correlated with patients' age (r = 0.489, p < 0.01), diabetic status (r = 0.327, p < 0.01), peritoneal fluid absorption rate (Ke; r = 0.251, p < 0.05), PP (r = 0.483, p < 0.01), and E/T (r = 0.517, p < 0.01). Multivariate regression analysis showed that C-F PWV was independently related to E/T (p < 0.01), PP (p < 0.01), age (p < 0.05), and Ke (p < 0.05). Peritoneal fluid transport (Ke), as well as E/T, age and PP were found to be independent predictors of elevated C-F PWV in CAPD patients, suggesting that there might be a link between high aortic stiffness and increased Ke rate, hypothetically through generalized vasculopathy.
    American Journal of Nephrology 02/2008; 28(1):128-32. · 2.62 Impact Factor
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    ABSTRACT: Hypoalbuminemia is a risk factor for cardiovascular events and mortality in dialysis patients, but the underlying mechanism remains unclear. Meanwhile, increased pulse wave velocity (PWV), the marker of arterial stiffness, has been proved to be an independent predictor of cardiovascular disease. The relationship between serum albumin and PWV in continuous ambulatory peritoneal dialysis patients (CAPD) was studied. Sixty-two CAPD patients were studied. The average age was 63 +/- 12 years and dialysis duration was 23 +/- 22 months. Serum albumin, C-reactive protein (CRP), and carotidfemoral PWV were measured. Among these patients, 43.5% were men. The mean serum albumin concentration was 37 +/- 4 g/L and PWV was 11.9 +/- 2.3 m/s. PWV positively correlated with age (r = 0.35, P < 0.01), diabetes (yes=1, no=0; r = 0.292, P < 0.05), systolic blood pressure (SBP; r = 0.493, P < 0.001) and CRP (r = 0.295, P < 0.05), but negatively correlated with serum albumin (r = -0.357, P < 0.01). In multiple regression analysis, SBP (beta = 0.615, P < 0.001), age (beta = 0.414, P < 0.01), albumin (beta = -0.315, P < 0.05) and total cholesterol (beta = 0.275, P < 0.05) were independent determinants of PWV. In a non-inflamed subgroup (CRP < 3 mg/L, n=30), albumin still negatively correlated with PWV (r = -0.66, P < 0.001). Serum albumin inversely correlated with increased PWV in CAPD patients, suggesting that increased arterial stiffness might be the link between hypoalbuminemia and increased cardiovascular mortality in dialysis patients.
    Vascular Health and Risk Management 02/2008; 4(4):871-6.
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    ABSTRACT: Volume overload is believed to play a pivotal role in the pathogenesis of hypertension in dialysis patients. Although the extracellular water (ECW) content in hypertensive dialysis patients was significantly higher than in normotensive dialysis patients on the whole, there was considerable overlap in ECW between the two groups. Little is known about the hemodynamic characteristics in subgroups of patients with normotension but a high volume (HV) status or with hypertension but a normal volume (NV) status. We investigate the overlap in ECW between controlled and uncontrolled hypertension in dialysis patients. Fifty-two patients (mean age 62 years, 26 males and 26 females) on peritoneal dialysis were enrolled into this study. The ECW was assessed by bioimpedance analysis and normalized by individual height in meters (NECW). The mean value of NECW in both sexes was arbitrarily set to define NV status (lower than mean value) or HV status (higher than mean value). All patients were thus divided into four subgroups: controlled hypertension with NV (CHT-NV), controlled hypertension with HV (CHT-HV), uncontrolled hypertension with NV (UHT-NV) and uncontrolled hypertension with HV (UHT-HV). The stroke volume, cardiac output and total peripheral resistance were echocardiographically measured and their respective indices were calculated. There were 12 (23%), 8 (15%), 14 (27%) and 18 (35%) patients in the CHT-NV, CHT-HV, UHT-NV and UHT-HV subgroups, respectively. The four subgroups were matched for sex, diabetes and age. The NECW in the CHT-HV group was higher than that in CHT-NV and UHT-NV groups (p < 0.01), but was comparable with that in the UHT-HV group. The stroke volume and cardiac output indices in the CHT-HV group were not significantly different from those in the CHT-NV and UHT-NV groups. The total peripheral resistance index in the CHT-HV group was lower than that in UHT-NV and CHT-NV groups (p < 0.05), but was comparable to that in the UHT-HV group. There was no difference in heart rate among the four groups. The overlap in ECW between controlled hypertension and uncontrolled hypertension in dialysis patients was related to a significant difference in total peripheral resistance index, but not to significant differences in stroke volume and cardiac output indices. The CHT-HV patients were characterized by lower total peripheral resistance indices.
    American Journal of Nephrology 01/2008; 28(3):508-16. · 2.62 Impact Factor
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    ABSTRACT: Although the augmentation index (AIx) is widely used to evaluate arterial stiffness in clinics and research, some conflicting data exist in regard to its validity. We therefore performed a series of studies to test the validity of AIx. The first study in 196 peritoneal dialysis patients showed that AIx in diabetics was lower than that in non-diabetic patients (p<0.05), which was in contradiction with the previous studies. Further analysis showed that AIx was just weakly correlated with pulse pressure (PP)-a known index of arterial stiffness. We also found that the increase of augmentation pressure (AP) was usually accompanied with increased central PP (C-PP). As AP and C-PP are used as the numerator and denominator in the AIx formula, an increase in the numerator (AP) would not necessarily result in an increase of the quotient (AIx) unless the denominator (C-PP) was stable. We then conducted a second study trying to test the validity of AIx through mathematical ratiocination. The increases in the central second peak (P2) and AP were assumed to represent increased arterial stiffness. Different values of AIx were obtained by varying the central initial systolic peak (P1) and diastolic pressure (DP). Mathematical ratiocination showed that AIx was dependent on multiple factors, F=(DeltaSP-DeltaDP)x(P1-P2)+(DeltaP2-DeltaP1)x(SP-DP), which suggested that a change of AIx would not always be attributable to changes in P2 and AP. This speculation was further proved by clinical data in our third study. In conclusion, through a series of studies and ratiocination, we showed that the augmentation index (AIx or AIx@75bpm) might not be a sensitive surrogate for a change in central pressure waveforms, which is a manifestation of change in large artery function. The limitation of AIx as an index of arterial stiffness is rooted in its formula, which has a clear mathematical flaw.
    Hypertension Research 08/2007; 30(8):713-22. · 2.79 Impact Factor
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    ABSTRACT: A seasonal variation in blood pressure (BP) has been observed in hemodialysis and renal transplant patients. However, this phenomenon in continuous ambulatory peritoneal dialysis (CAPD) patients, whose hemodynamics are different from hemodialysis patients, has not been reported before. In addition, the contribution of extracellular water (ECW) in the seasonal variation in BP is not clear. All stable CAPD patients (n = 122) dialyzed in a single center from January 1, 2003 to December 12, 2004 were studied. Systolic blood pressure (SBP), diastolic blood pressure (DBP), weight and ECW (by bioimpedance analysis) were measured in every patient. Climatic data were obtained from the Beijing Weather Bureau. These data were pooled together and grouped according to the calendar month. In general, an apparent seasonal variation in BP was observed in CAPD patients. BP began to decrease from spring and reached the lowest level in summer, then increased from autumn and reached its peak in winter. The seasonal variation in BP in male patients was similar to that in female patients, but in comparison to non-diabetic patients there was no apparent seasonal variation in the BP of diabetic patients. SBP and DBP negatively correlated with the average atmospheric temperature (r = -0.768, p < 0.001 and r = -0.764, p < 0.001, respectively). BP also negatively correlated with rainfall and humidity, but this correlation disappeared when temperature was controlled in partial correlation analysis. Weight and ECW fluctuated throughout the year but showed no seasonal variation. On the whole there was an apparent seasonal variation in blood pressure in CAPD patients. As opposed to non-diabetic patients, there was no apparent seasonal variation in BP in diabetic patients. The seasonal variation in BP was influenced more by temperature than rainfall and humidity, and the change in ECW was not seasonal, suggesting that other mechanisms such as total peripheral resistance might play a more important role in this phenomenon.
    Blood Purification 02/2006; 24(5-6):499-507. · 2.06 Impact Factor