The impact of the aortic pulse wave velocity on the cardiovascular outcomes of hemodialysis patients

Effect of Menaquinone-7 Supplementation on Arterial Stiffness in Chronic Hemodialysis Patients: A Multicenter Randomized Controlled Trial

BACKGROUND

There is a very high prevalence of subclinical vitamin K deficiency in patients requiring hemodialysis (HD), and this problem is associated with vascular calcification and arterial stiffness. Vitamin K2 (MK-7) supplementation can improve vitamin K status in HD patients. However, the benefits of vitamin K supplementation on arterial stiffness have still not been established. The present study was conducted to evaluate the efficacy of menaquinone-7 (MK-7) supplementation on arterial stiffness in chronic HD patients.

METHODS

This open-label multicenter randomized clinical trial was conducted in 96 HD patients who had arterial stiffness, defined by high carotid femoral pulse wave velocity (cfPWV ≥ 10 m/s). The patients were randomly assigned to receive oral MK-7 (375 mcg once daily) for 24 weeks (n = 50) or standard care (control group; n = 46). The change in cfPWV was the primary outcome.

RESULTS

Baseline parameters were comparable between the two groups. There was no significant difference in the change in cPWV at 24 weeks between the MK-7 group and standard care [-6.0% (-20.2, 2.3) vs. -6.8% (-19.0, 7.3), p = 0.24]. However, we found that MK-7 significantly decreased cPWV in patients with diabetes [-10.0% (-15.9, -0.8) vs. 3.8% (-5.8, 11.6), p = 0.008]. In addition, the MK-7 group had a lower rate of arterial stiffness progression, compared to controls (30.2% vs. 39.5%, p = 0.37), especially in diabetes patients (21.4% vs. 72.7%, p = 0.01). No serious adverse events were observed during the 24 weeks.

CONCLUSION

Vitamin K supplements provided a beneficial impact in lowering the rate of arterial stiffness progression in chronic hemodialysis patients with diabetes. Possible benefits on cardiovascular outcomes require further investigation.

Chronic Kidney Disease and Pulse Wave Velocity: A Narrative Review

Chronic kidney disease (CKD) is associated with excess cardiovascular mortality, resulting from both traditional and nontraditional, CKD-specific, cardiovascular risk factors. Nontraditional risk factors include the entity Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) which is characterised by disorders of bone and mineral metabolism, including biochemical abnormalities of hyperphosphatemia and hyperparathyroidism, renal osteodystrophy, and vascular calcification. Increased arterial stiffness in the CKD population can be attributed amongst other influences to progression of vascular calcification, with significant resultant contribution to the cardiovascular disease burden. Pulse wave velocity (PWV) measured over the carotid-femoral arterial segments is the noninvasive gold-standard technique for measurement of aortic stiffness and has been suggested as a surrogate cardiovascular end-point. A PWV value of 10 m/s or greater has been recommended as a suitable cut-off for an increased risk of cardiovascular mortality. CKD is a risk factor for an excessive rate of increase in aortic stiffness, reflected by increases in PWV, and increased aortic PWV in CKD shows faster progression than for individuals with normal kidney function. Patients with varying stages of CKD, as well as those on dialysis or with a kidney transplant, have different biological milieu which influence aortic stiffness and associated changes in PWV. This review discusses the pathophysiology of arterial stiffness with CKD and outlines the literature on PWV across the spectrum of CKD, highlighting that determination of arterial stiffness using aortic PWV can be a useful diagnostic and prognostic tool for assessing cardiovascular disease in the CKD population.

Pulse wave velocity and central aortic pressure in systolic blood pressure intervention trial participants

Arterial stiffness, typically assessed as the aortic pulse wave velocity (PWV), and central blood pressure levels may be indicators of cardiovascular disease (CVD) risk. This ancillary study to the Systolic Blood Pressure Intervention Trial (SPRINT) obtained baseline assessments (at randomization) of PWV and central systolic blood pressure (C-SBP) to: 1) characterize these vascular measurements in the SPRINT cohort, and 2) test the hypotheses that PWV and C-SBP are associated with glucose homeostasis and markers of chronic kidney disease (CKD). The SphygmoCor^® CPV device was used to assess carotid-femoral PWV and its pulse wave analysis study protocol was used to obtain C-SBP. Valid results were obtained from 652 participants. Mean (±SD) PWV and C-SBP for the SPRINT cohort were 10.7 ± 2.7 m/s and 132.0 ± 17.9 mm Hg respectively. Linear regression analyses for PWV and C-SBP results adjusted for age, sex, and race/ethnicity in relation to several markers of glucose homeostasis and CKD did not identify any significant associations with the exception of a marginally statistically significant and modest association between PWV and urine albumin-to-creatinine ratio (linear regression estimate ± SE, 0.001 ± 0.0006; P-value 0.046). In a subset of SPRINT participants, PWV was significantly higher than in prior studies of normotensive persons, as expected. For older age groups in the SPRINT cohort (age > 60 years), PWV was compared with a reference population of hypertensive individuals. There were no compelling associations noted between PWV or C-SBP and markers of glucose homeostasis or CKD.

Clinical Trial Registration: NCT01206062.

Brachial-ankle pulse wave velocity predicts decline in renal function and cardiovascular events in early stages of chronic kidney disease

OBJECTIVE

In this study, we investigated the predictive capacity of the brachial-ankle aortic pulse wave velocity (baPWV), a marker of arterial stiffness, for the decline in renal function and for cardiovascular events in the early stages of chronic kidney disease (CKD).

METHOD

Two hundred forty-one patients who underwent a comprehensive check-up were included and were divided into two groups according to their estimated glomerular filtration rates (eGFR): patients with CKD categories G2, G3a and G3b (30 ≤ eGFR < 90 ml/min/1.73m(2), eGFR < 90 group; n=117) and those with eGFR ≥ 90 ml/min/1.73 m(2) (eGFR ≥ 90 group; n=124). The change in renal function, the eGFR change, was determined by the slope of eGFR against time. We analysed whether baPWV was associated with eGFR change or predicted cardiovascular events.

RESULTS

baPWV was independently associated with eGFR change in a multivariate analysis of the total patients (β=-0.011, p=0.011) and remained significantly associated with eGFR change in a subgroup analysis of the eGFR < 90 group (β=-0.015, p=0.035). baPWV was independently associated with cardiovascular events (odds ratio=1.002, p=0.048) in the eGFR < 90 group, but not in the eGFR ≥ 90 group. The receiver operative characteristic curve analysis showed that 1,568 cm/sec was the cut-off value of baPWV for predicting CV events in the eGFR < 90 group (area under curve=0.691, p=0.03) CONCLUSIONS: In patients with early stages of CKD, baPWV was independently associated with the decline in renal function and short-term cardiovascular events.

Arterial micro-calcification of vascular access is associated with aortic arch calcification and arterial stiffness in hemodialysis patients

Vascular calcification of the coronary arteries or aorta is an independent risk factor for cardiovascular outcome, but clinical significance of arterial micro-calcification (AMC) of vascular access is unclear in hemodialysis (HD) patients. Sixty-five patients awaiting vascular access operation were enrolled. We compared surrogate markers of cardiovascular morbidity such as aortic arch calcification (AoAC) by chest radiography, arterial stiffness by brachial-ankle pulse wave velocity (baPWV) and endothelial dysfunction by flow-mediated dilatation (FMD) between patients with and without AMC of vascular access on von Kossa staining. AMC of vascular access was detected in 36 (55.4%). The AMC-positive group had significantly higher incidence of AoAC (63.9% vs. 20.7%, p < 0.001) and higher baPWV (26.5 ± 9.4 m/s vs. 19.8 ± 6.6 m/s, p = 0.006) than the AMC-negative group. There was no significant difference in FMD between the two groups (5.4 ± 2.6% vs. 5.7 ± 3.5%, p = 0.764). The AMC-positive group had higher incidence of diabetes mellitus, higher systolic blood pressure and wider pulse pressure than the AMC-negative group. This study suggests that AMC of vascular access may be associated with cardiovascular morbidity via AoAC and arterial stiffness in HD patients.